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energies Article Design and Application of a Power Unit to Use Plug-In Electric Vehicles as an Uninterruptible Power Supply Gorkem Sen 1 , Ali Rifat Boynuegri 2 , Mehmet Uzunoglu 2, *, Ozan Erdinc 2,3 and João P. S. Catalão 3,4,5 1 2 3 4 5 * Department of Electronics and Automation, Ipsala Vocational School, Trakya University, Ipsala, Edirne 22400, Turkey; [email protected] Department of Electrical Engineering, Faculty of Electric-Electronics, Yildiz Technical University Davutpasa Campus, Esenler, Istanbul 34220, Turkey; [email protected] (A.R.B.); [email protected] (O.E.) Instituto de Engenharia de Sistemas e Computadores—Investigação e Desenvolvimento (INESC-ID), Inst. Super. Tecn., University of Lisbon, Av. Rovisco Pais, 1, Lisbon 1049-001, Portugal; [email protected] Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, Porto 4200-465, Portugal Department of Electromechanical Engineering, University of Beira Interior, R. Fonte do Lameiro, Covilhã 6201-001, Portugal Correspondence: [email protected]; Tel.: +90-212-383-5807 Academic Editor: K. T. Chau Received: 8 January 2016; Accepted: 26 February 2016; Published: 7 March 2016 Abstract: Grid-enabled vehicles (GEVs) such as plug-in electric vehicles present environmental and energy sustainability advantages compared to conventional vehicles. GEV runs solely on power generated by its own battery group, which supplies power to its electric motor. This battery group can be charged from external electric sources. Nowadays, the interaction of GEV with the power grid is unidirectional by the charging process. However, GEV can be operated bi-directionally by modifying its power unit. In such operating conditions, GEV can operate as an uninterruptible power supply (UPS) and satisfy a portion or the total energy demand of the consumption center independent from utility grid, which is known as vehicle-to-home (V2H). In this paper, a power unit is developed for GEVs in the laboratory to conduct simulation and experimental studies to test the performance of GEVs as a UPS unit in V2H mode at the time of need. The activation and deactivation of the power unit and islanding protection unit are examined when energy is interrupted. Keywords: grid-enabled vehicles; distributed generation; plug-in electric vehicles; plug-in hybrid electric vehicles; vehicle-to-home; uninterruptible power supply 1. Introduction The world faces an environmental crisis as the volatile prices of petroleum meet rising concerns regarding each nation’s energy independence and global warming issues due to greenhouse gas (GHG) emissions. In this regard, the transportation sector plays a crucial and growing role in world energy use and, accordingly, GHG emissions, accounting for approximately 15% of overall GHG emissions [1,2]. These factors contribute to increase interest in alternative vehicle technologies. Nowadays, electrification of transportation has become an important, supported industry trend. Along the past few years, grid-enabled vehicles (GEVs) such as plug-in electric vehicles (PEVs) and plug-in hybrid electric vehicles (PHEVs) are growing in popularity due to increasing governmental regulations on industries and public will to reduce GHG emissions [3]. Given GEVs’ popularity, different types are estimated to constitute 35% of the automotive market by 2025 [4]. For this reason, Energies 2016, 9, 171; doi:10.3390/en9030171 www.mdpi.com/journal/energies Energies 2016, 9, 171 2 of 17 many automotive manufacturers have already started to expand their productions to benefit from the growing GEV market. In the near future, increasing number of GEVs will be connected to power distribution systems for charging their batteries [5]. In [6], Electric Power Research Institute (EPRI) estimates new vehicle market shares of conventional vehicles (CVs) and PHEVs using a choice-based market modeling of customer choice. Results of this report suggest that CVs will have a market share of 56%, 14%, and 5% and PHEVs will have a market share of 20%, 62%, and 80% by 2050 in low, medium, and high penetration scenarios, respectively. In Morgan Stanley’s report [7], specific information is used to forecast sales of GEVs. Market demand of GEV is forecasted to reach one million by 2020. The study of Pacific Northwest National Laboratory (PNNL) [8] examines GEV market penetration scenarios. Yearly market penetration ratios for PHEVs are estimated from 2013 to 2045 for three scenarios: hybrid technology-based assessment, R&D goals achieved, and supply constrained scenarios, in which PHEV market penetration is estimated to reach 9.7%, 9.9%, and 26.9% by 2023, and 11.9%, 29.8%, and 72.7% by 2045, respectively. The study of Oak Ridge National Laboratory (ORNL) [9] estimates that the demand for GEVs will be almost one million by 2015 [9]. It is clear that massive integration of GEVs on the power distribution system will result in a significant increase in electric energy demand and will raise load values at peak times [10]. Also, various studies have already been carried out to predict the effects of GEVs on the power distribution system. As a result of these studies, GEVs have been observed to cause some special effects such as phase imbalance, power quality issues, grid stability, transformer degradation and failure, and circuit breaker and fuse blowout on the power distribution systems [11–15]. All these problems can be prevented with well-designed GEV battery chargers and intelligent charging as part of the smart grid technologies. Massive integration of batteries of GEVs into the power grid can create some opportunities. With smart grid technologies, the function of the GEVs as a mobile energy storage unit in the power grid includes some opportunities such as reactive power compensation, harmonic filtering, voltage support, reducing frequency fluctuations, functioning as an emergency power supply such as an uninterruptible power supply (UPS) which is often named as vehicle-to-home (V2H), improving the effectiveness of home renewable energies by using GEV as storage, load balancing, peak shaving unit [16–23]. However, the design and control of a GEV on-board battery charger is important to perform specified operating conditions. As it is well known, an energy storage unit that provides the required power for a vehicle is employed in GEVs. This energy storage unit must be recharged at charging points. Nowadays, the interaction of a commercial GEV with the grid is generally unidirectional—the charging process. However, GEVs can be operated bi-directionally by modifying the design of power units of GEV. Thus, the storage units can be supplied to small isolated systems such as single households without the power grid in V2H mode. Due to the large amount of energy stored in batteries of GEVs, they can supply the demand of the consumption center. The general scheme of the V2H operating condition is illustrated in Figure 1. V2H operating conditions would offer the possibility of using a GEV as a domestic back-up power as a UPS [24,25]. Instead, a power unit that can be utilized for the consumption center connection of vehicular systems is important for the realization of this operating condition. Energies 2016, 9, 171 Energies 2016, 9, 171 3 of 17 3 of 15 Figure 1. Block scheme of the V2H operating condition. Figure 1. Block scheme of the V2H operating condition. The simulation studies are performed in MATLAB & Simulink environments. For the The mainstudies, idea presented in this formed paper isby using GEVsgroup, as a power supply the consumption experimental a test platform a battery a power unit, to measurement units, center when needed. The proposed study contributes to the relevant literature regarding the fact an islanding protection unit, a load unit, a dead-time generation unit, and a dSPACE control unit is that both the simulation and the experimental analyses have been conducted for use of GEVs as UPS. configured to test V2H operating conditions—different from the existing literature, which considers The concept of using GEVs aspoint a UPSofunit is different from the regular UPS structures. Firstly, the GEVs the topic a solely theoretical view. are not continuously available at the residential as Section the GEV2 owners usethe their GEVs during The remainder of this paper is organized premises as follows: describes V2H simulation daily forhas traveling to work, etc. of GEVs for such purposes should be limited modellife that been developed and Besides, explains the the use physical configuration of the test platform as well by comfort conditions as the GEV owner requiring a minimum level of charge for his/her GEV for as the testing methodology; Section 3 demonstrates the simulation and experimental results; and possible unexpected GEV use during the evening, etc. Moreover, such systems should be continuously finally, conclusions are made in Section 4. controlled regarding the fact that battery charge/discharge lifetime is limited and uncontrolled daily use of GEVs for such purposes will present drawbacks in this regard. However, the GEVs can be 2. System Description and Methodology considered as a mobile UPS unit readily available during energy outages, etc. for supplying at least the In order to test and improve the effectiveness of the proposed methodology, an initial analysis minimum level of electrical energy for sustaining daily activities at home, work, etc. as GEVs are also is performed in a simulation environment before conducting experimental studies. In this simulation mostly idle during the daytime (at work, etc.) even when the GEV is not at home. A limitation for the study, the modeling and analysis of the prepared system are realized using MATLAB & Simulink, minimum State-of-Charge (SoC) is implemented within the control structure. In addition, an islanding Sim Power Systems. Afterwards, a test platform is established in order to use GEV as a UPS if unit is designed specifically for the mentioned type of use for GEVs in this study. necessary. The parameters of the components used in the test platform are normalized to real GEV The simulation studies are performed in MATLAB & Simulink environments. For the experimental specifications. The concept of the simulation model and test platform, control algorithms, and the studies, a test platform formed by a battery group, a power unit, measurement units, an islanding principle of the operation as well as the general structure of the V2H are explained in detail in the protection unit, a load unit, a dead-time generation unit, and a dSPACE control unit is configured to following subsections. test V2H operating conditions—different from the existing literature, which considers the topic a solely theoretical point of view. 2.1. Simulation Model The remainder of this paper is organized as follows: Section 2 describes the V2H simulation allbeen subsystems of the structure in theconfiguration performed simulation areas prepared modelFirstly, that has developed andgeneral explains the physical of the test study platform well as separately. The simulation study consists of four units: Battery, DC-DC converter, DC-AC converter the testing methodology; Section 3 demonstrates the simulation and experimental results; and finally, (inverter), and load conclusions are the made in model. Section The 4. block diagram of the prepared system is shown in Figure 2 and the simulation model is given in Figure 3. Also, the parameter values used in the simulation are given in Table1. In this simulation study, the charging process of the GEV is not included in order to reduce the complexity in a model that mainly focuses on the V2H operating mode. For this reason, the power grid and the islanding protection unit are not modeled and used in the simulation study. Energies 2016, 9, 171 4 of 17 2. System Description and Methodology In order to test and improve the effectiveness of the proposed methodology, an initial analysis is performed in a simulation environment before conducting experimental studies. In this simulation study, the modeling and analysis of the prepared system are realized using MATLAB & Simulink, Sim Power Systems. Afterwards, a test platform is established in order to use GEV as a UPS if necessary. The parameters of the components used in the test platform are normalized to real GEV specifications. The concept of the simulation model and test platform, control algorithms, and the principle of the operation as well as the general structure of the V2H are explained in detail in the following subsections. 2.1. Simulation Model Firstly, all subsystems of the general structure in the performed simulation study are prepared separately. The simulation study consists of four units: Battery, DC-DC converter, DC-AC converter (inverter), and the load model. The block diagram of the prepared system is shown in Figure 2 and the simulation model is given in Figure 3. Also, the parameter values used in the simulation are given in Table 1. In this simulation study, the charging process of the GEV is not included in order to reduce the complexity in a model that mainly focuses on the V2H operating mode. For this reason, Energies 2016, 9, 171 4 of 15 the power grid and the islanding protection unit are not modeled and used in the simulation study. Under operation is is important for safety Under normal normal conditions, conditions, islanding islanding operation important for safety as as it it separates separates the the power power grid grid Energies 2016, 9, 171 center. Thus, the electrical energy generated by the GEV is only consumed 4 of 15 and the consumption by the and the consumption center. Thus, the electrical energy generated by the GEV is only consumed by consumption center in the V2H operation mode by this way the staff of the grid operator can safely the consumption in the V2H operation by this the of thethe grid operator Under normal center conditions, islanding operation mode is important forway safety as staff it separates power grid can rectify the fault. Also even when the power grid isgrid powered up again the GEV is temporarily kept safelyand rectify the fault. Also even when the power is powered up again the GEV is temporarily the consumption center. Thus, the electrical energy generated by the GEV is only consumed by mechanically isolated to protect the power converters from transient effects that may occur. kept the mechanically isolated to the protect powermode converters transient that may occur. consumption center in V2H the operation by thisfrom way the staff ofeffects the grid operator can safely rectify the fault. Also even when the power grid is powered up again the GEV is temporarily kept mechanically isolated to protect the power converters from transient effects that may occur. Figure 2. 2. General scheme of of the the simulation simulation model. model. Figure General scheme Figure 2. General scheme of the simulation model. Figure3. 3. Simulation Simulation model. Figure model. Figure 3. Simulation model. Table1.1.Parameters Parameters of of the Table thesimulation simulationsystem. system. Parameters Parameters Battery Voltage (V) Battery Voltage (V) Battery Ah Value (Ah) Battery AhSoC Value Battery (%) (Ah) Battery SoC (%) DC/DC Converter Type DC/DC Converter DC/DC ConverterType Output Voltage (V) DC/DC ConverterOutput Switching Frequency DC/DC Converter Voltage (V) (kHz) DC/AC Converter Type DC/DC Converter Switching Frequency (kHz) DC/AC ConverterType Control Method DC/AC Converter DC/AC Converter Switching Frequency (kHz) DC/AC Converter Control Method Filter Inductance Value (mH) DC/AC Converter Switching Frequency (kHz) Filter Capacitor Value (µ F) Values Values 240 240 10 10 100 100 Bidirectional Bidirectional 450 15450 Full 15Bridge Sinusoidal PWM Full Bridge 10Sinusoidal PWM 0.03 10 100 Energies 2016, 9, 171 5 of 17 Table 1. Parameters of the simulation system. Parameters Values Battery Voltage (V) Battery Ah Value (Ah) Battery SoC (%) DC/DC Converter Type DC/DC Converter Output Voltage (V) DC/DC Converter Switching Frequency (kHz) DC/AC Converter Type DC/AC Converter Control Method DC/AC Converter Switching Frequency (kHz) Filter Inductance Value (mH) Filter Capacitor Value (µF) 240 10 100 Bidirectional 450 15 Full Bridge Sinusoidal PWM 10 0.03 100 In this study, as the first unit in simulation, the existing battery model within the Simulink library was selected. The type of battery is lithium-ion and the battery values determined as 240 V, 10 Ah, and initial SoC of 100%. The second unit is a load model that models the consumption center in the simulation study. This load model consists of a controlled voltage source, resistor, and the control block of the controlled voltage source. As the basic operating principle of this system, control block of the load model generates the reference voltage value of the controlled voltage source and current is drawn through 1 ohm virtual resistance. The control inputs of the load unit are active power (P), reactive power (Q), and the instantaneous value of the voltage at the load connection point (V) is used as a feedback signal to calculate reference current value. The mentioned P and Q values of a three-story office building are used. The output of the load model is the voltage signal generated for the controlled voltage source. The signal method for the controlled voltage source is shown in Figure 4. Energies 2016,production 9, 171 5 of 15 Figure 4. Control block of load model. Figure 4. Control block of load model. First, as in Figure 4, angle (φ) is calculated in the unit of radians. The power factor (cos φ) value First, as in Figure 4, angle is calculated in the unit radians. powerthe factor (cosdifference ϕ) value is calculated with φ. Also, φ is(ϕ) converted to seconds fromofradians forThe creating phase is calculated with ϕ. and Also, ϕ voltage. is converted to seconds phase difference between the current the Afterwards, thefrom RMSradians value offor thecreating currentthe is calculated so that between the current and the voltage. Afterwards, the RMS value of the current is calculated so wave that the the peak value of the current can be specified. After all of these processes, a pure sine is peak valuewith of the current can beangle specified. all of these processes, a pure sine wave is generated generated the same phase with After the voltage of load connection point. This reference wave with same phase angleand with the voltage point. This reference wave form is form the is shifted to φ angle multiplied by of theload peakconnection value of the current and the reference current shifted to ϕ angle and multiplied by the peak value of the current and the reference current signal signal is produced. Finally, the measured current signal is subtracted from the voltage value on the is produced. Finally, measured current signal is subtracted from thesource voltage on the load load connection point.the Thus, the control signal for the voltage controlled is value produced. connection point. Thus, the control signal for the voltage controlled source is produced. The third unit is a DC–DC converter, which generates an appropriate DC voltage for the The input. third unit a DC–DC converter, whichbi-directional generates an operation appropriate DC voltage the inverter inverter ThisisDC–DC converter requires (charging andfor discharging of input. This DC–DC converter requires bi-directional operation (charging and discharging of the the battery). In this simulation study, the bi-directional DC–DC converter is operated only for battery). In this study, the bi-directional is operated for discharging discharging thesimulation battery. The charging of the GEV DC–DC battery converter is not in the scope of only this study; relevant the battery. The charging the GEV in battery is not in the scope of this study;converter relevant control charging charging methodologies areofpresented [24]. Therefore, a bi-directional DC–DC is methodologies are presented in [24]. Therefore, a bi-directional DC–DC converter control is realized realized just for the boost operating state. In control unit of the converter, the reference and just for the values boost operating state. In control unit of theFirst, converter, the reference values of measured of DC bus voltage are required. the control unit ofand themeasured DC–DC converter receives the information of the DC bus voltage in the DC–DC converter output. Then, the reference voltage information is compared with the measured voltage in the PI controller. The DC reference voltage value is chosen as 425 VDC for resembling the voltage value at load connection to the grid voltage value. After this process, a pulse width modulation (PWM) signal is obtained by comparison of a saw tooth signal, with the signal received from the output of PI controller. Afterward, zero The third unit is a DC–DC converter, which generates an appropriate DC voltage for the inverter input. This DC–DC converter requires bi-directional operation (charging and discharging of the battery). In this simulation study, the bi-directional DC–DC converter is operated only for discharging the battery. The charging of the GEV battery is not in the scope of this study; relevant charging methodologies are presented in [24]. Therefore, a bi-directional DC–DC converter control Energies 2016, 9, 171 6 of 17is realized just for the boost operating state. In control unit of the converter, the reference and measured values of DC bus voltage are required. First, the control unit of the DC–DC converter DC bus voltage are required. First, of the DC–DC converter receives thethe information receives the information of the DCthe buscontrol voltageunit in the DC–DC converter output. Then, reference of the DC bus voltage in the DC–DC converter output. Then, the reference voltage information is voltage information is compared with the measured voltage in the PI controller. The DC reference compared withisthe measured the PI controller. The DC reference valuetoisthe chosen voltage value chosen as 425voltage VDC forinresembling the voltage value at loadvoltage connection grid as 425 V for resembling the voltage value at load connection to the grid voltage value. After this DC voltage value. After this process, a pulse width modulation (PWM) signal is obtained by comparison process, a pulse width modulation (PWM) signal is obtained by comparison of a saw tooth signal, with of a saw tooth signal, with the signal received from the output of PI controller. Afterward, zero the signal received from the output controller. zero is S1 given S1 switch signal is given to the S1 switch and of thePIPWM signalAfterward, is sent to the S2signal switch. andto S2the switches are and the PWM signal is sent to the S2 switch. S1 and S2 switches are shown in Figure 3. In order to shown in Figure 3. In order to maintain the DC bus voltage, the control algorithm presented in maintain the DC bus voltage, the control algorithm presented in Figure 5 is used. Figure 5 is used. Figure 5. Control algorithm of DC–DC converter during V2H operation mode. Figure 5. Control algorithm of DC–DC converter during V2H operation mode. The fourth and the last unit is the power unit. This unit includes an inverter and the LC filter, The the last unit is the power unit. Thispulse unit width includes an inverter and thecontrol LC filter, which is fourth locatedand in the inverter output. A sinusoidal modulation (SPWM) is which is located in the inverter output. A sinusoidal pulse width modulation (SPWM) control is applied at the aforementioned inverter. Due to the SPWM method, the switching elements (IGBT, applied at are the entered aforementioned Due to the SPWM method, the switching elements MOSFET) in cutoffinverter. mode and transmission mode to generate a sinusoidal wave(IGBT, form MOSFET) areperiod. enteredThus, in cutoff mode and transmission modesignal to generate sinusoidalAwave form during each the variable amplitude sinusoidal can bea obtained. sinusoidal during period. Thus, thewith variable amplitude sinusoidal signal can for be obtained. sinusoidal control each signal is compared a higher frequency triangle wave achievingAthe desired control signal is compared with a higher frequency triangle wave for achieving the desired frequency frequency of SPWM. In this comparison result, the SPWM signals required for cross-arms of the of SPWM. thisobtained. comparison the SPWM signals for cross-arms power unitInare An result, LC passive filter is used required to filter the harmonics of onthe thepower outputunit of are the obtained. An LC passive filter is used to filter the harmonics on the output of the inverter. The filter’s inverter. The filter’s inductance and capacitor values are selected as 0.03 mH and 100 μF, inductance and capacitor are and selected as 0.03 mH 100 µF,the respectively. The filter is designed respectively. The filter is values designed implemented toand minimize system harmonics. and implemented to minimize the system harmonics. All subsystems in the simulation study are prepared separately, as mentioned before. Then, the All subsystems in the simulationisstudy are prepared mentioned before. Then, the interconnection of these subsystems performed and theseparately, simulationas results are obtained. interconnection of these subsystems is performed and the simulation results are obtained. 2.2. Test Platform An experimental test platform is built to verify the controller system design and to implement a successful connection between the GEV and the end-user premise. The parameters of the components used in the test platform are normalized to certain values in order to reduce high costs, minimize the size of the components, and achieve flexible controllability. This test platform consists of a battery, a power unit (inverter), measurement units, an islanding protection unit, a dead-time generation unit, and a dSPACE control unit. The block diagram of the mentioned system is given in Figure 6. The test platform for experimental studies is shown in Figure 7. Also, the values of components used in the test platform are given in Table 2. components used in the test platform are normalized to certain values in order to reduce high costs, minimize the size of the components, and achieve flexible controllability. This test platform consists of a battery, a power unit (inverter), measurement units, an islanding protection unit, a dead-time generation unit, and a dSPACE control unit. The block diagram of the mentioned system is given in Figure 6.9,The Energies 2016, 171 test platform for experimental studies is shown in Figure 7. Also, the values7 of of 17 Figure 6. General scheme of the test platform. components used in the test platform are given in Table 2. Table 2. Parameters of the test platform. Parameters Values Battery Voltage (V) 24 Battery Ah Value (Ah) 18 Battery SoC (%) 100 Power Unit Type Inverter Power Unit Control Method Sinusoidal PWM Power Unit Switching Frequency (kHz) 10 Filter Inductance Value (mH) 1 Filter Capacitor Value (µ F) 15 Figure 6. General scheme of the test platform. Figure 6. General scheme of the test platform. Load (Ω) 17 Table 2. Parameters of the test platform. Parameters Battery Voltage (V) Battery Ah Value (Ah) Battery SoC (%) Power Unit Type Power Unit Control Method Power Unit Switching Frequency (kHz) Filter Inductance Value (mH) Filter Capacitor Value (µ F) Load (Ω) Values 24 18 100 Inverter Sinusoidal PWM 10 1 15 17 Figure 7. Photograph of the test platform. Figure 7. Photograph of the test platform. Table 2. Parameters of the test platform. Parameters Values Battery Voltage (V) 24 Battery Ah Value (Ah) 18 Battery SoC (%) 100 Power Unit Type Inverter Power Unit Control Method Sinusoidal PWM Power Unit Switching Frequency (kHz) 10 Filter Inductance Value 1 Figure(mH) 7. Photograph of the test platform. Filter Capacitor Value (µF) 15 Load (Ω) 17 2.2.1. Control Algorithm The control algorithm was developed utilizing MATLAB & Simulink and SimPowerSystems. A dSPACE embedded control unit is used as the controller in experimental studies. The control algorithm of the test platform, as illustrated in Figure 8, includes eight input and two output signals. Five of the input signals are measurement data taken from sensors. At first, these measurement data enter the calibration block and signals are converted to the actual values. Then, the calibrated signals enter the data storage block. The grid voltage information is sent to the grid monitoring block from The control algorithm was developed utilizing MATLAB & Simulink and SimPowerSystems. A dSPACE embedded control unit is used as the controller in experimental studies. The control algorithm of the test platform, as illustrated in Figure 8, includes eight input and two output signals. Five of the input signals are measurement data taken from sensors. At first, these measurement data Energies 2016, 9, 171 8 of 17 enter the calibration block and signals are converted to the actual values. Then, the calibrated signals enter the data storage block. The grid voltage information is sent to the grid monitoring block from the of of incoming gridgrid voltage is checked if it isifinit the voltage range the data datastorage storageblock. block.The Theinformation information incoming voltage is checked is in the voltage specified by the grid block. Accordingly, the islanding the protection signal is generated. Also, range specified by monitoring the grid monitoring block. Accordingly, islanding protection signal is some data are sent to the V2H block, which provides safe system operation. These data are generated. Also, some data are control sent to the V2H control block, which provides safe system operation. the battery the terminal of the powervoltage unit, respectively. Furthermore, the V2H These datavoltage are theand battery voltagevoltage and the terminal of the power unit, respectively. control block receives confirmation signal ofthe theconfirmation end-user, SoC limit,of the price of electricity, and the Furthermore, the V2Hthe control block receives signal the end-user, SoC limit, the islanding protectionand signal the grid monitoring block. Depending on these inputsV2H operation price of electricity, thefrom islanding protection signal from the grid monitoring block. Depending is by generating SPWM signal. The signalSPWM generated by dSPACE is applied to the power onstarted these inputsV2H operation is started bySPWM generating signal. The SPWM signal generated by unit through the dead-time generation unit in order to perform the energy transfer from the battery dSPACE is applied to the power unit through the dead-time generation unit in order to perform the to the load. In addition this generated signal, the dSPACE unitsignal, transmits another control energy transfer from thetobattery to the load. In addition to thiscontrol generated the dSPACE control signal to the islanding protection for commissioning andprotection decommissioning Lastly,and the unit transmits another control unit signal to the islanding unit forprocedures. commissioning decommissioning procedures. Lastly, SPWM block operates to the confirmation signal SPWM block operates according to thethe confirmation signal of theaccording end-user and generates the driving of the required end-userfor and generates the In driving signal required forthe theSPWM powerblock unit. for In this experimental signal the power unit. this experimental study, the power unit is study, theatSPWM block for the power unit is operated at 10 kHz. operated 10 kHz. Figure 8. 8. The The control control algorithm algorithm of of the the test test platform. platform. Figure 2.2.2. Operation Operation of of the the Test Test Platform Platform 2.2.2. Initially, the the battery battery group group and and the the power power unit unit representing representing aa GEV GEV are are connected connected to to the the grid grid Initially, connectionpoint pointvia viaaatransformer. transformer.However, However, this study, GEV is operated a UPS therefore connection inin this study, GEV is operated as aasUPS andand therefore the the charging of the battery is not included in the experimental study and the power unit is employed charging of the battery is not included in the experimental study and the power unit is employed only only for discharging the battery. The reason for using a transformer theplatform test platform the quite for discharging the battery. The reason for using a transformer in theintest is theisquite low low level of battery voltage according togrid the grid voltage. At beginning the beginning of experimental the experimental study, level of battery voltage according to the voltage. At the of the study, the the grid supplies the load and GEV is in standby depending the of status of the grid. power grid. grid supplies the load and GEV is in standby mode,mode, depending on the on status the power After a After a while, the power failure occurs on the grid side and the load does not remain energized. As while, the power failure occurs on the grid side and the load does not remain energized. As a result ofa result of this the recommended V2H operating mode will take action. Frommoment, this moment, the power this fault, thefault, recommended V2H operating mode will take action. From this the power unit unit requires the formation of the necessary conditions to operate as an UPS. Those conditions are: requires the formation of the necessary conditions to operate as an UPS. Those conditions are: the initial initial SoC SoC of of the the battery batteryisisgreater greaterthan thanthe thereference referenceSoC SoClimit, limit, ‚ IfIf the the end-user end-user gives gives permission permissionfor forV2H, V2H, ‚ IfIf the If the islanding protection process is realized (the grid is isolated from loads and power unit), ‚ If the islanding protection process is realized (the grid is isolated from loads and power unit), If the voltage value of the power unit is approximately zero regarding the measurement unit signal, ‚ If the voltage value of the power unit is approximately zero regarding the measurement unit signal, If the price of electricity is greater than the reference price value (optional). ‚ If the price of electricity is greater than the reference price value (optional). If all of the foregoing conditions are met, the control system formed by dSPACE allows GEV to be operated as a UPS. In this V2H operating mode, the power unit is operated as voltage-controlled and the power flow is provided from the battery to the loads. The last step is the termination of this operation mode. There are several conditions for the termination of this operation mode. The mentioned conditions for operation termination are: If all of the foregoing conditions are met, the control system formed by dSPACE allows GEV to be operated as a UPS. In this V2H operating mode, the power unit is operated as voltage-controlled and the power flow is provided from the battery to the loads. The last step is the termination of this operation mode. There are several conditions for Energies 2016, 9, 171 9 ofthe 17 termination of this operation mode. The mentioned conditions for operation termination are: ‚ ‚ ‚ If the the SoC SoC of of the the battery battery is is lower lower than than the the reference reference SoC SoC limit, limit, If If the the end-user end-user cancels cancels the the operation operation status, status, If If the measurement signals of the grid side show show existence If the measurement signals of the grid side existence of of energy energy (if (if the the voltage voltage value value of of the the power grid is within appropriate values for standards), power grid is within appropriate values for standards), ‚ If the the price price of of grid grid electricity electricity is is more more than than the the reference reference value value (optional). (optional). If As a result of the provision of one or more termination conditions, dSPACE terminates sending As a result of the provision of one or more termination conditions, dSPACE terminates sending signals to the power unit through the dead-time generation unit. After that, dSPACE receives and signals to the power unit through the dead-time generation unit. After that, dSPACE receives and evaluates data coming from sensors. As a result of this evaluation, dSPACE interrupts the signal of evaluates data coming from sensors. As a result of this evaluation, dSPACE interrupts the signal of the the islanding protection unit (contactor) when there is no problem in terms of security islanding protection unit (contactor) when there is no problem in terms of security (approximately two (approximately two cycles). Consequently, the grid-load connection can be realized again. cycles). Consequently, the grid-load connection can be realized again. 3. 3. Results Results In In this this section, section, the the behavior behavior of of the the GEV GEV in in V2H V2H operation operation mode mode is is examined examined firstly firstly by by the the simulation studies (results presented in Section 3.1). After the simulation results are evaluated, simulation studies (results presented in Section 3.1). After the simulation results are evaluated, experimental are shown shown and and discussed discussed in in Section Section 3.2. 3.2. experimental results results are 3.1. Simulation Results The load demand of a three-story office building located in Istanbul was used in the simulation study. On the theday dayofofmeasurement, measurement,building buildingrenovation renovation work was in progress. Therefore, some of study. On work was in progress. Therefore, some of the the electrical loads were continuously engaged or disengaged. In the simulation study, these power electrical loads were continuously engaged or disengaged. In the simulation study, these power values valuesused were as the load demand values active and power reactivedrawn powerfrom drawn from GEV, as were asused the load demand values for activefor and reactive GEV, as shown in shown inIn Figure order show the results, simulation results, a period of 10 s was the Figure 9. order9.toIn show thetosimulation a period of 10 s was selected whenselected the loadwhen demand load at demand was at the maximum. was the maximum. Figure Figure 9. 9. The The load load demand demand values values and and power power values values drawn drawn from from the the GEV. GEV. The load demand and the power values drawn from the GEV coincide with each other The load demand and the power values drawn from the GEV coincide with each other successfully. successfully. An abrupt change was observed at the time of an instant power change due to the An abrupt change was observed at the time of an instant power change due to the instantaneous instantaneous response of the mathematical operations performed in the simulation study. response of the mathematical operations performed in the simulation study. Eventually, proper Eventually, proper functioning of the prepared load model and accuracy of the control of the functioning of the prepared load model and accuracy of the control of the converters can be observed converters can be observed from Figure 9. from Figure 9. It is necessary to maintain the DC bus voltage at the reference voltage value for maintaining the RMS value of the terminal voltage of the load model the same as the power grid. The mentioned DC bus voltage variation is presented in Figure 10. As seen, some fluctuations can be observed in DC Energies 2016, 9, 171 9 of 15 Energies 2016, 9, 171 Energies 2016, 9, 171 10 of 17 9 of 15 It is necessary to maintain the DC bus voltage at the reference voltage value for maintaining the RMS value of the terminal voltage of the load model the same as the power grid. The mentioned DC It is necessary to maintain the DC bus voltage the reference voltage value maintaining the bus voltage variation is presented in Figure 10. Asatseen, some fluctuations can for be observed in DC bus voltage as the load powervoltage demand varies. During periods of lower power demand, the DC DC bus RMS value of the terminal of the load model the same as the power grid. The mentioned bus voltage as the load power demand varies. During periods of lower power demand, the DC bus voltage can successfully be maintained at the reference voltage value. As the power demand increases, bus voltage variation isbe presented in Figure 10. As seen, some fluctuations can be observed in DC voltage can successfully maintained at the reference voltage value. As the power demand increases, the fluctuations of the DC bus voltage increase as well. However, the controller keeps the mentioned bus voltage as the load power demand varies. During periods of lower power demand, the DC bus the fluctuations of the DC bus voltage increase as well. However, the controller keeps the mentioned voltage can successfully be maintained at the reference voltage value. As the power demand increases, fluctuations within acceptable limits and therefore ensures the successful operation of the system. fluctuations within acceptable limits and therefore ensures the successful operation of the system. the fluctuations of the DC bus voltage increase as well. However, the controller keeps the mentioned fluctuations within acceptable limits and therefore ensures the successful operation of the system. Figure 10. The voltage of the DC bus. Figure 10. The voltage of the DC bus. Figureof 10.the Thepower voltageunit of the bus. in Figure 11. The RMS value of The terminal voltage fluctuations areDC shown the voltage at the end offluctuations load is maintained to 220 V are in spite of high power values drawn The terminal voltage of theclose power unit shown in Figure 11. The RMSfrom value of The terminal voltagefluctuation fluctuations of the power unit areand shown in Figure 11. voltage The RMS value of the battery. This voltage is within the standards therefore proper regulation the voltage at the end of load is maintained close to 220 V in spite of high power values drawn from theprovided. voltage at the end of load is maintained close to 220 V in spite of high power values drawn from is the battery. This voltage fluctuation is within the standards and therefore proper voltage regulation the battery. This voltage fluctuation is within the standards and therefore proper voltage regulation is provided. is provided. Figure 11. The terminal voltage fluctuations of the power unit. Figure 11. The terminal voltage of the power unit.drawn by the load in Finally, the change load voltage valuefluctuations and the current Figureof11.the The terminal voltage fluctuations of thevariation power unit. Figure 12 show that the whole system is operating successfully. It is important to notice whether the Finally, the change of acceptably the load voltage and thedemand current variations. variation drawn by the of load in voltage waveform is kept steadyvalue during load The change load Finally, change ofwhole the load voltage value successfully. and the current variation by the the load in Figure 12the show that the system is operating It is important to drawn notice whether voltage waveform is kept acceptably duringsuccessfully. load demand It variations. The change of load Figure 12 show that the whole system steady is operating is important to notice whether the voltage waveform is kept acceptably steady during load demand variations. The change of load terminal voltage when the highest change of active load occurs in the eighth second, shown in Figure 12, indicates the change of the current drawn by the load at the same time range. After the change of the Energies 2016, 9, 171 Energies 2016, 9, 171 10 of 15 11 of 17 terminal voltage when the highest change of active load occurs in the eighth second, shown in 10 of 15 Figure 12, indicates the change of the current drawn by the load at the same time range. After the load values at the eighth second, the prepared system has been successfully adapted to this change change of the load values at the eighth second, the prepared system has been successfully adapted to terminal voltage when highest change of active load occurs in the eighth second, shown in and has continued into the the current study. this change and has continued into the current study. Figure 12, indicates the change of the current drawn by the load at the same time range. After the change of the load values at the eighth second, the prepared system has been successfully adapted to this change and has continued into the current study. Energies 2016, 9, 171 Figure 12. The waveform of the terminal voltage of load model and load current. Figure 12. The waveform of the terminal voltage of load model and load current. Eventually, all units of the simulation system operate successfully, as claimed by the data obtained Figure 12. The waveform of the terminal voltage of load model and load current. from all figures. Theseofresults show that the GEVs can successfully be used as an UPS necessary. Eventually, all units the simulation system operate successfully, as claimed byifthe data obtained from all figures. These results show that thesystem GEVsoperate can successfully used asby anthe UPS if obtained necessary. Eventually, all units of the simulation successfully,be as claimed data 3.2. Experimental Results from all figures. These results show that the GEVs can successfully be used as an UPS if necessary. 3.2. Experimental Once theResults simulation results validated the control algorithms and V2H operation mode, the test 3.2. Experimental Results platform was built to support the obtained simulation results. At the beginning of the experimental Once the simulation results validated the control algorithms and V2H operation mode, the test study, the grid voltage is within specified limits and the grid supplies the load in this process. At the the simulation results validated simulation the control algorithms operation the test platform Once was built to support the obtained results. Atand theV2H beginning ofmode, the experimental same time, the GEV is awaiting at full charge depending on the grid. After that, the time of the grid was built to support the obtained simulation results. At the beginning ofinthe experimental study,platform the grid voltage is within specified limits and the grid supplies the load this process. At the voltage is decreasing outside of the specified limits is shown in Figure 13. The dSPACE unit receives study, the grid voltage is within specified limits and the grid supplies the load in this process. At the samethe time, GEV is awaiting full charge on the the time of the gridthe voltage and current at values from thedepending measurement unitgrid. at theAfter grid that, side and ensures the grid same time, the GEV is awaiting at full charge depending on the grid. After that, the time of the grid voltage is decreasing outside of the specified limits is shown in Figure 13. The dSPACE unit receives opening of the contactor through sending a signal to the islanding protection unit. The islanding voltage is decreasing outside of the specified limits is shown in Figure 13. The dSPACE unit receives the grid voltagesignal, and current values from theRMS measurement the grid and ensures the13. opening protection the waveform, and the value of theunit gridatvoltage areside illustrated in Figure the grid voltage and current values from the measurement unit at the grid side and ensures the of theopening contactor through sending a signal to the islanding protection unit. The islanding protection of the contactor through sending a signal to the islanding protection unit. The islanding signal, the waveform, and the RMSand value thevalue grid of voltage are illustrated in Figure protection signal, the waveform, the of RMS the grid voltage are illustrated in 13. Figure 13. Figure 13. The waveform of the grid voltage when the power grid fails. (a) Grid voltage [V] (b) Grid voltage [Vrms] (c) Islanding protection signal. Figure 13. The waveform of the grid voltage when the power grid fails. (a) Grid voltage [V] (b) Grid Figure 13. The waveform of the grid voltage when the power grid fails. (a) Grid voltage [V] (b) Grid voltage [Vrms] (c) Islanding protection signal. voltage [Vrms] (c) Islanding protection signal. Energies 2016, 9, 171 Energies 2016, 9, 171 12 of 17 11 of 15 The signal shown in Figure 13c is the control signal sent from dSPACE to the islanding protection The signal shown in Figure 13c is the control signal sent from dSPACE to the islanding unit. protection The islanding unit is disabled the control signal value is 0.value Thus, the energy unit. protection The islanding protection unitwhen is disabled when the control signal is 0. Thus, the flow from energy the power thepower loads grid is realized. The islanding unitprotection is activated and mechanically flowgrid fromtothe to the loads is realized.protection The islanding unit is activated separates loads and power grid from thepower moment that the control signal is signal 1. Furthermore, and mechanically separates loads and grid from the moment that thevalue control value is 1. the RMS Furthermore, value of gridthe voltage is reduced zero after a period waveforms; thisofsituation is shown RMS value of gridtovoltage is reduced to of zero after a period waveforms; this in situation is main shownreasons in Figure The main are reasons for measuring this situation are that the Figure 13b. The for 13b. this situation that the equipment canmeasuring measure RMS equipment measure values afterreduction one periodisand the displayed is within values after onecan period andRMS the displayed within a period reduction of the power grid.a period of the grid. of the experimental study, the waveform of the terminal voltage of the power In thepower first stage In the first stage of the experimental study, the waveform of the terminal voltage of the power unit is shown in Figure 14a and the RMS value of voltage of the power unit is shown in Figure 14b. unit is shown in Figure 14a and the RMS value of voltage of the power unit is shown in Figure 14b. After the islanding protection unit is activated, GEV begins to supply loads after a short time. This After the islanding protection unit is activated, GEV begins to supply loads after a short time. situation presented in Figurein14c. Approximately one-period delay is set by dSPACE to secure This is situation is presented Figure 14c. Approximately one-period delay is set by dSPACE to the operating status of the test platform, which was expressed previously in Section 2. secure the operating status of the test platform, which was expressed previously in Section 2. Figure 14. The waveform of the terminal voltage of the power unit when the power grid fails. (a) Terminal Figure 14. The waveform of the terminal voltage of the power unit when the power grid fails. voltage of the power unit [V] (b) Terminal voltage of the power unit [Vrms] (c) Islanding protection signal. (a) Terminal voltage of the power unit [V] (b) Terminal voltage of the power unit [Vrms] (c) Islanding protection signal. Lastly, the change of the battery voltage is shown in Figure 15 at the time of the islanding protection signal received. Initially, the fully charged battery is in standby mode until the islanding protection process is performed. After the islanding protection process, the battery voltage remains at the same value while the inverter is waiting for the provision of the necessary conditions for operation. When the power unit starts, the battery supplies the load and the battery voltage value decreases slightly. Figure 15. The change of the battery voltage when the power grid fails. (a) Battery voltage [V] (b) Islanding protection signal. Figure 14.9,The Energies 2016, 171waveform of the terminal voltage of the power unit when the power grid fails. (a) Terminal 13 of 17 voltage of the power unit [V] (b) Terminal voltage of the power unit [Vrms] (c) Islanding protection signal. Energies 2016, 9, 171 12 of 15 Lastly, the change of the battery voltage is shown in Figure 15 at the time of the islanding protection signal received. Initially, the fully charged battery is in standby mode until the islanding protection process is performed. After the islanding protection process, the battery voltage remains at the same value while the inverter is waiting for the provision of the necessary conditions for operation. When the power unit starts, the battery supplies the load and the battery voltage value decreases slightly. In the last stage of the experimental study, the response of the test platform is examined when the power grid is powered up again. When the voltage value of the grid is within standard limits again, the flow of energy from GEV to the load is terminated and load demand is satisfied by the grid again. These situations are illustrated in Figures 16–18. Figure 15. 15. The The change change of ofthe thebattery battery voltagewhen when thepower power grid fails. Battery voltage Figure fails. (a)(a) Battery voltage [V] [V] (b) The waveform of the grid voltagevoltage and its RMSthe value aregrid shown in Figure 16a,b respectively, (b) Islanding protection signal. Islanding protection signal. when the power grid is online again. As seen in Figure 16c, the value of the islanding protection signal is 0 shortly after the grid voltage is within specified limits. Thus, the islanding protection unit In the last stage of thethe experimental study, response of the platform is of examined the remains inactivated and grid supplies the the loads. Despite the test improvement the gridwhen voltage, power grid powered upprotection again. When theisvoltage value of the grid istime. within standard limitsfor again, the value ofisthe islanding signal zero again after a certain The main reason this the flow of energy from GEV to the load is terminated and load demand is satisfied by the grid again. is that dSPACE waits for the realization of the previously mentioned security requirements in These are safety illustrated in Figuresensure 16–18.the safe and effective operation of the whole system. Sectionsituations 2.2.2. These requirements Figure 16. The waveform of the grid voltage when the power grid is powered up again. (a) Grid Figure 16. The waveform of the grid voltage when the power grid is powered up again. (a) Grid voltage [V] (b) Grid voltage [Vrms] (c) Islanding protection signal. voltage [V] (b) Grid voltage [Vrms] (c) Islanding protection signal. Figure 17 shows the change of the terminal voltage of the power unit and the islanding protection signal when the power grid is online again. After receiving the information indicating that the grid voltage is within specified limits, the operation of the power unit is terminated. Before islanding operation is terminated, the RMS value of the output voltage of the power unit reaches nearly zero in terms of security. Thus, the grid can be used to supply the load again. Lastly, the change of the battery voltage is shown in Figure 18. Primarily, the grid voltage reaches the specified limit. Then, dSPACE stops the operation of the power unit. From this moment on, the battery voltage is restored to the initial values. After obtaining all the safety requirements, dSPACE terminates the islanding protection. The results of the experimental study show that all the units of the test platform perform successfully under the normalized conditions. Consequently, GEVs can be used as a UPS if the electrical infrastructure and power unit control are prepared properly. Energies 2016, 9, 171 14 of 17 Energies 2016, 9, 171 Energies 2016, 9, 171 13 of 15 13 of 15 Figure 17. The The waveform of the terminal voltage of the power unit when the power grid is powered Figure Figure 17. 17. The waveform waveform of of the the terminal terminal voltage voltage of of the the power power unit unit when when the the power power grid grid is is powered powered up again. (a) Terminal voltage of the power unit [V] (b) Terminal voltage of the power unit up again. (a) (a) Terminal Terminal voltage voltage of of the the power power unit unit [V] [V] (b) (b) Terminal Terminal voltage of the the power power unit unit [Vrms] [Vrms] up again. voltage of [Vrms] (c) Islanding Islanding protection protection signal. signal. (c) (c) Islanding protection signal. Figure 18. Change of the battery voltage when the power grid is powered up again. Figure 18. Change of the battery voltage when the power grid is powered up again. Figure 18. Change voltage when the power grid is powered up again. (a) Battery voltage (a) Battery voltage of [V]the (b)battery Islanding protection signal. (a) Battery voltage [V] (b) Islanding protection signal. [V] (b) Islanding protection signal. 4. Conclusions 4. Conclusions The waveform of the grid voltage and have its RMS value are shown Figurewhich 16a,b respectively, when Recently, a great number of studies been performed oninGEVs, are considered to Recently, aisgreat number of studies have been performed on GEVs, which are considered the power grid online again. As seen in Figure 16c, the value of the islanding protection signal isto 0 provide zero emissions. In these studies, it is declared that this GEV technology will gradually provideafter zerothe emissions. In these studies, it is declared that the thisislanding GEV technology will gradually shortly grid voltage is within specified limits. Thus, protection unit remains become widespread in the near future. As it is well known, an energy storage unit that provides the become widespread in the near future. As it Despite is well known, an energy storage unitvoltage, that provides the inactivated and the supplies the loads. the improvement the should grid the value required power for agrid vehicle is employed in GEVs. This energy storageofunit be recharged at required power for a vehicle is employed in GEVs. energy storage should befor recharged at of the islanding signal is zero afterThis certain The unit main reason this can is that charging points. protection Also, another reason foragain this type ofa GEV to time. be popular is that the vehicle be charging points. Also, another reason for this type of GEV to be popular is that the vehicle can be dSPACE waits forgrid. the realization of the the interaction previously mentioned security requirements in Section connected to the Nowadays, of GEV with the grid is bi-directional, as is2.2.2. the connected torequirements the grid. Nowadays, the interaction of GEV with the grid is bi-directional, as is the These safety ensure the safe and effective operation of the whole system. charging process. However, GEVs can be operated bi-directionally by modifying the design of a charging process. However, GEVs can be operated bi-directionally by modifying the design of a Figure 17 shows change the terminal voltage of the power the islanding vehicle’s power unit the or units. Inofsuch operating condition, a GEVunit can and be operated as aprotection UPS and vehicle’s power unit or units. In such operating condition, a GEV can be operated as a UPS and signal when the power gridofisthe online again. After receiving the information indicating that the grid supply the energy demand consumption center. supply the energy demand of the consumption center. Before starting the study, it was assumed that battery of a GEV can supply a portion of an Before starting the study, it was assumed that battery of a GEV can supply a portion of an end-user premise’s load. The test system was prepared primarily in a simulation environment for end-user premise’s load. The test system was prepared primarily in a simulation environment for Energies 2016, 9, 171 15 of 17 voltage is within specified limits, the operation of the power unit is terminated. Before islanding operation is terminated, the RMS value of the output voltage of the power unit reaches nearly zero in terms of security. Thus, the grid can be used to supply the load again. Lastly, the change of the battery voltage is shown in Figure 18. Primarily, the grid voltage reaches the specified limit. Then, dSPACE stops the operation of the power unit. From this moment on, the battery voltage is restored to the initial values. After obtaining all the safety requirements, dSPACE terminates the islanding protection. The results of the experimental study show that all the units of the test platform perform successfully under the normalized conditions. Consequently, GEVs can be used as a UPS if the electrical infrastructure and power unit control are prepared properly. 4. Conclusions Recently, a great number of studies have been performed on GEVs, which are considered to provide zero emissions. In these studies, it is declared that this GEV technology will gradually become widespread in the near future. As it is well known, an energy storage unit that provides the required power for a vehicle is employed in GEVs. This energy storage unit should be recharged at charging points. Also, another reason for this type of GEV to be popular is that the vehicle can be connected to the grid. Nowadays, the interaction of GEV with the grid is bi-directional, as is the charging process. However, GEVs can be operated bi-directionally by modifying the design of a vehicle’s power unit or units. In such operating condition, a GEV can be operated as a UPS and supply the energy demand of the consumption center. Before starting the study, it was assumed that battery of a GEV can supply a portion of an end-user premise’s load. The test system was prepared primarily in a simulation environment for testing and improving the accuracy of the planned system and algorithm and the system was tested with the real measured power data of a building. The voltage, frequency, etc., values remained within standards and the building could be supplied with high-quality energy. The results of the simulation study showed that the proposed test system can be used successfully in daily life as a UPS. Afterwards, the test platform was established to present the verification of the controller system design and to implement a successful vehicle–home connection. The experimental results showed that the established test platform performed successfully under normalized conditions and can be practically implemented. The activation and deactivation of the power unit and islanding protection unit were realized in as rapid (approximately two cycles) and safe a way as possible when energy was interrupted on the test platform. To this end, it should be noted that the idea of the V2H operating conditions has been confirmed by successful simulation and experimental studies. It is expected that the developed test platform can also be adapted to any GEV and end-user type, thus enabling GEVs to be employed for other purposes apart from transportation. In addition, this concept can also be used in different situations, such as emergency disasters such as earthquakes and blackouts. Acknowledgments: This work was supported in part by the Istanbul Chamber of Industry research projects fund. Besides, this work was supported by FEDER funds through COMPETE and by Portuguese funds through FCT, under FCOMP-01-0124-FEDER-020282 (Ref. PTDC/EEA-EEL/118519/2010), UID/CEC/50021/2013 and SFRH/BPD/103744/2014. Also, the research leading to these results has received funding from the EU Seventh Framework Programme FP7/2007-2013 under grant agreement no. 309048 (project SiNGULAR). Author Contributions: Gorkem Sen and Ali Rifat Boynuegri mainly contributed by realizing the simulation and experimental analyses. Besides, all co-authors contributed by significant technical suggestions and improvements through the research steps and also contributed to the writing of the final research paper. Conflicts of Interest: The authors declare no conflict of interest. Abbreviations The following abbreviations are used in this manuscript: CV conventional vehicle Energies 2016, 9, 171 EPRI GEV GHG ORNL PEV PHEV PNNL SoC UPS V2H 16 of 17 Electric Power Research Institute grid-enabled vehicle greenhouse gas Oak Ridge National Laboratory plug-in electric vehicle plug-in hybrid electric vehicle Pacific Northwest National Laboratory state of charge uninterruptible power supply vehicle-to-home References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Plug-in Hybrid Electric Vehicles. Available online: http://ns.umich.edu/Releases/2009/Oct09/PHEV_Curtin.pdf (accessed on 7 January 2016). Reducing Transport Greenhouse Gas Emissions: Trends & Data 2010. Available online: http://www. internationaltransportforum.org/Pub/pdf/10GHGTrends.pdf (accessed on 7 January 2016). Tarroja, B.; Eichman, J.D.; Zhang, L.; Brown, T.M.; Samuelsen, S. 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