Download Automotive system CONCLUSION

DC–DC CONVERTER FOR DUAL-VOLTAGE AUTOMOTIVE SYSTEMS BASED ON
BIDIRECTIONAL HYBRID SWITCHED-CAPACITOR ARCHITECTURES
ABSTRACT:
Automotive embedded electronic systems have been increasing in power and complexity
and, therefore, more advanced power electronic converters are necessary in these vehicles.
Several dual-voltage (42 V/14 V) bidirectional converter architectures have been proposed for
automotive systems in recent years. However, most of them have low efficiency or are based in
series and parallel configurations with large number of semiconductors and magnetics devices.
Therefore, in this paper, we propose a bidirectional high-efficiency converter with lower number
of components. This converter was created by merging a switched-capacitor converter and a
conventional bidirectional converter, resulting in a hybrid topology. The voltage across the
semiconductors of the proposed converter is equal to half of the highest voltage source value.
Furthermore, the topology is composed of only one inductor to control the power flow between
the two voltage sources. To verify all the mentioned features, a prototype was implemented
experimentally, reaching a maximum efficiency of 97.5%.
INTRODUCTION:
The Automotive industry has benefited from permanent technological advances that have
been increasing the need for more advanced power electronics devices. While electric loads on
vehicles are nowadays set around 2 kW, in the next few years, the electric power consumed may
overcome 5 kW for internal combustion engine vehicles and 40 kW for fully electric vehicles.
This increase in energy demand is due to the massive use of electronic systems, which allows
more comfort and flexibility.
Thus, it will be unviable to maintain the 14 V in automotive systems, due to the high current
levels through the electronic devices. Therefore, 42-V systems have been increasingly used in
automotive applications. Studies show the benefits of using a 42-V system in vehicles. Some of
these benefits are the improvement of electronics efficiency and, consequently, lower losses.
In addition, the boost converter has relatively high switch voltage stress which is equal to the
output voltage. Also, the boost rectifier has some practical drawbacks, such that, input–output
isolation cannot easily be implemented, the startup inrush current is high, and there is a lack of
current limiting during overload conditions.
Furthermore, it is well known that the boost converter operating in discontinuous current mode
(DCM) can offer a number of advantages, such as inherent PFC function, very simple control,
soft turn-on of the main switch, and reduced diode reversed-recovery losses.
However, the DCM operation requires a high-quality boost inductor since it must switch
extremely high peak ripple currents and voltages. As a result, a more robust input filter must be
employed to suppress the high-frequency components of the pulsating input current, which
increases the overall weight and cost of the rectifier.
In addition, several PFC topologies based on flyback, buck-boost, and Cuk converters have been
published. However, these topologies have an inverting output. On the other hand, SEPIC
rectifier has several advantages such as: Step up and step down capabilities in addition to
magnetic coupling that will lead to reduction in input current ripple a wide static gain SEPIC
converter operating in continuous conduction mode (CCM) have been proposed to increase the
static gain at low input voltage without extreme switch duty-cycle and with reduced switch
voltage stress. This has been achieved by inserting a voltage multiplier cell (DM and CM) in the
conventional SEPIC converter
EXISTING SYSTEM:
In this configuration, the 42-V bus will supply high-power loads, whereas the 14-V bus
will provide energy for the low-power components. Several dual-voltage converter architectures
have been proposed in recent years. A conventional solution to designing the electronic interface
for a dual-voltage system is a bilateral dc–dc converter. This topology is composed of a buck and
a boost converter separated in two different stages sharing the same magnetic core. As an
advantage, this topology has low number of components. However, when it is designed for high
power applications (>1 kW), it requires high-voltage and high current semiconductors.
PROPOSED SYSTEM:
In this paper, we propose a bidirectional high-efficiency converter with lower number of
components. This converter was created by merging a switched-capacitor converter and a
conventional bidirectional converter, resulting in a hybrid topology. The voltage across the
semiconductors of the proposed converter is equal to half of the highest voltage source value.
Furthermore, the topology is composed of only one inductor to control the power flow between
the two voltage sources
ADVANTAGES:

The current ripple is low.

Adding more capacitors modules at the output, increasing even more the static gain,
preserving the same low voltage across the switches
BLOCK DIAGRAM:
TOOLS AND SOFTWARE USED:

MPLAB – microcontroller programming.

ORCAD – circuit layout.

MATLAB/Simulink – Simulation
APPLICATIONS:

Automotive system
CONCLUSION:
This paper has presented a detailed study of a bidirectional hybrid SC dc–dc converter for
a dual-voltage automotive system. The proposed converter is composed of four switches, three
capacitors, and one inductor. As in the conventional dc–dc boost converter, at the low voltage
and high current side, the proposed converter has low current ripple, in opposition to most of the
previously reported topologies, which is a suitable feature in automotive applications. The
steady-state and dynamic analyses were carried out using state-space averaging methods due to
the complexity of the system when the nonidealities of the circuit are considered. Using this kind
of representation, the RMS and average currents through capacitors and switches were
determined and plotted for different duty cycles. From this analysis, it was found that switch S1
is the component, which has the highest current and, consequently, the highest power losses in
the circuit.
REFERENCES:
[1] A. Consoli, M. Cacciato, G. Scarcely, and A. Testa, “Compact, reliable efficiency,” IEEE
Ind. Appl. Mag., vol. 10, no. 6, pp. 35–42, Nov./Dec. 2004.
[2] B. K. Bose, “Global energy scenario and impact of power electronics in 21st century,” IEEE
Trans. Ind. Electron., vol. 60, no. 7, pp. 2638, 2651, Jul. 2013.
[3] M. A. Shrud, A. Bousbaine, A. S. Ashur, R. Thorn, and A. Kharaz, “42 V power system
architecture development,” in Proc. 3rd Inst. Eng. Technol. Conf. Autom. Electron., Jun. 28/29,
2007, pp. 1, 17.
[4] F. Z. Peng, F. Zhang, and Z. Qian, “A magnetic-less DC-DC converter for dual-voltage
automotive systems,” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 511, 518, Mar./Apr. 2003.
[5] F. Zhang, L. Du, F. Z. Peng, and Z. Qian, “A new design method for high-power highefficiency switched-capacitor DC-DC converters,” IEEE Trans. Power Electron., vol. 23, no. 2,
pp. 832, 840, Mar. 2008.