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REDUCED-CAPACITY SMART CHARGER FOR ELECTRIC VEHICLES ON SINGLE-PHASE THREE-WIRE DISTRIBUTION FEEDERS WITH REACTIVE POWER CONTROL ABSTRACT: In this paper, we propose a new control algorithm to reduce the capacity of a previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders with reactive power control. The basic principle of the proposed control algorithm is discussed in detail. It is shown that controlling the reactive power on the source side reduces the capacity of the previously proposed smart charger. A digital computer simulation is implemented to confirm the validity of the proposed control algorithm using PSIM software. A prototype experimental model is also constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of 0.9, which is acceptable for Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during both the battery charging and discharging operations in EVs. The capacity of dc capacitor CDC is also reduced by 37% with the proposed reactive power control algorithm. INTRODUCTION: The charger, which uses the PWM rectifier with a bidirectional dc–dc converter, can support the grid in the following ways: 1) time-of-day-based coordination of the charging power; 2) regulation of the reactive power when connected to the grid; and 3) returning power to the grid when there is a need for peak shaving. Various studies analyzing the value and the potential impact of these effects on the utility grid have been reported. The analysis of the reactive power operation in a charger was described in detail. The operation modes of the proposed battery charger were divided into quadrants based on the active and reactive power on the ac side. Then, the control method, the dc capacitor design, the ac inductor design, and the loss evaluation were discussed. Other small-capacity loads are connected to each feeder with a neutral line, and their voltage rating is 105 Vrms. The load conditions are always unbalanced. If the charger is connected to single-phase three-wire distribution feeders, perfect reactive power compensation for each feeder with a power factor of unity cannot be achieved on the low voltage side. Moreover, unbalanced conditions remain on the secondary side of the pole-mounted distribution transformer. This imbalance causes an imbalance in the feeder voltages. It is well known that this imbalance of the source current on the secondary side of the distribution transformer increases the loss in the distribution transformer. Balancing the currents on the two feeders is effective for balancing the feeder voltages and reducing the losses. EXISTING SYSTEM: A charger with a three-leg-structured PWM rectifier with a bidirectional dc–dc converter for a split-phase transformer in single-phase three-wire feeders has been proposed. However, the third leg is controlled by fixed 50% duty to keep the two output voltages of 120 Vrms balance. Thus, unbalanced active and reactive currents cannot be compensated on the secondary side of the pole-mounted distribution transformer. The proposed smart charger, reducing the capacity of the three-leg PWM rectifier, which performs as the smart charger, is strongly required. A sourceside power factor of 0.9 is acceptable. Thus, controlling the reactive power on the source side is effective for reducing the capacity of the proposed smart charger. In this paper, we propose a new control algorithm for the previously proposed smart charger to reduce the capacity of the three-leg PWM rectifier, which performs as the smart charger, with reactive power control on the source side. PROPOSED SYSTEM: The proposed smart charger consists of four-leg insulated-gate bipolar transistors (IGBTs). The first and second legs are connected to Feeder1 and Feeder2, respectively. The third leg is connected to the neutral line. These three legs are used as a single-phase PWM rectifier, which converts power from ac to dc during the battery charging operation or from dc to ac during the battery discharging operation. This PWM rectifier can compensate reactive and unbalanced active currents on single phase three-wire distribution feeders by connecting the third leg to the neutral line. When EVs are not connected to the proposed charger, the power quality is also improved on the secondary side of the pole-mounted distribution transformer. ADVANTAGES: The capacity of dc capacitor CDC is reduced by 37% with the proposed reactive power control algorithm. BLOCK DIAGRAM: PASSIVE FILTER THREE PHASE CONVERTER DC TO DC CONVERTER 12V DC DRIVER CIRCUIT 5V DC PIC CONTROLLER WITH BUFFER BATTERY TOOLS AND SOFTWARE USED: MPLAB – microcontroller programming. ORCAD – circuit layout. MATLAB/Simulink – Simulation APPLICATIONS: Electric vehicles (EVS ) CONCLUSION: In this paper, we have proposed a new control algorithm to reduce the capacity of the previously proposed smart charger with reactive power control. The smart charger consists of fourleg structured IGBTs. Three legs are used for a single-phase PWM rectifier, where two legs are connected to each feeder and the third leg is connected to the neutral line. This PWM rectifier can compensate reactive and unbalanced active currents on single-phase three-wire distribution feeders. The fourth leg is used as a bidirectional dc–dc converter for battery charging and discharging operations. The authors have shown theoretically that controlling the reactive power on the source side can reduce the capacity of the previously proposed smart charger. The basic principle of the proposed control algorithm was discussed in detail and then confirmed by digital computer simulation using PSIM software. REFERENCES: [1] Y. Mitani, “Method and system leveling power load,” Japan Patent Office, 4862 153 (P4 862 153), Jan. 25, 2012. [2] Nissan Motor Corporation. [Online]. com/EN/NEWS/2011/_STORY/110802-01-e.html Available: http://www.nissanglobal.