Multiple – Input Bidirectional DC -DC Power Converter with Renewable Energy Source



A novel multiple–input converter with bidirectional power flow capability is proposed in this paper. By using bidirectional power flow approch, not only the buck mode but also the boost mode of operation can be possible. Moreover, by establishing single power converter for different sources we can reduce the components and so the size of overall system and cost can be reduced. In this topology independent of voltage level interconnection of voltage sources can be possible. One of the source used is solar panel which holds the predominant place for satsfying the futur enegry demand. In fuel cell vehicles different sources which having unequal voltage rating is needed with bidirectional power flow. Thus the proposed topology finds application in fuel cell vehicles (FCVs)/hybrid electric vehicles (HEVs).The operation principle, theoretical analysis, and design of the proposed converter are presented in this paper. Simulation results are used to verify both the exactness and feasibility of the proposed converter.


  1. DC –DC power converter
  2. Multiple input converter



Fig. 1. Functional block diagram of a FCV system



 Fig. 2. Simulation result of mode E inductor currents, voltages and dc link current

Fig. 3. Simulation result of mode F inductor currents, voltages and

dc link current

Fig. 4. Simulation result of mode G inductor currents, voltages and

dc link current


This paper has proposed a multiple-input bidirectional dc–dc converter to interface more than two sources of power/energy operating at different voltage levels. The converter can be operated either in buck mode or boost mode in either directions of power flow. It is possible to control the power flow between each pair of sources independently when more than two sources are active. This paper gives detailed analysis and operation of the converter for various modes. In each mode, the relationship between the sources is derived which assists in the implementation of the controller. Simulations are done with three sources. Results obtained from these systems have been presented and match very well with the analytically expected waveforms. This converter not only finds application in FCVs but also can be utilized in distributed energy resources, smart grid and microgrid, battery management systems, etc., where more than two dc sources need to be interfaced with bidirectional power flow capability


[1] S. Aso, M. Kizaki, and Y. Nonobe, “Development of hybrid fuel cell vehicles in Toyota,” in Proc. IEEE PCC, 2007, pp. 1606–1611

[2] K. Rajashekhara, “Power conversion and control strategies for fuel cell vehicles,” in Proc. IEEE IECON, 2003, pp. 2865–2870.

[3] C. Chan, “The state of the art of electric and hybrid vehicles,” Proc. IEEE, vol. 90, no. 2, pp. 247-275, Feb. 2002

[4] B. Ozpineci, L. M. Tolbert, D. Zhong, “Multiple input converters for fuel cells,” in proc. Industry Applications Conference, 2004, vol. 2, pp. 791-797, 3-7 Oct. 2004

[5] Y.M. Chen, Y.C. Liu, and S.H. Lin, “Double-input PWM DC-DC converter for high/low voltage sources,” 25th International Telecommunications Energy Conference, 19-23 Oct. 2003, pp. 27–32.

An Efficient High-Step-Up Interleaved DC–DC Converter with a Common Active Clamp



This paper presents a high-efficiency and high-step up non isolated interleaved dc–dc converter with a common active clamp circuit. In the presented converter, the coupled-inductor boost converters are interleaved. A boost converter is used to clamp the voltage stresses of all the switches in the interleaved converters, caused by the leakage inductances present in the practical coupled inductors, to a low voltage level. The leakage energies of the interleaved converters are collected in a clamp capacitor and recycled to the output by the clamp boost converter. The proposed converter achieves high efficiency because of the recycling of the leakage energies, reduction of the switch voltage stress, mitigation of the output diode’s reverse recovery problem, and interleaving of the converters. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed, and its experimental results are presented for validation.


  1. Active-clamp
  2. Boost converter
  3. Coupled-inductor boost converter
  4. Dc–dc power converter
  5. High voltage gain
  6. Interleaving




 Fig. 1. (a) Parallel diode clamped coupled-inductor boost converter and (b) proposed interleaved coupled-inductor boost converter with single boost converter clamp (for n = 3).



Fig. 2. (a) Drain-to-source voltage of the switch in a coupled-inductor boost converter without any clamping and (b) output voltage, clamp voltage and drain to- source voltage of the switch in a coupled-inductor boost converter with the proposed active-clamp circuit.


Fig. 3. (a) From top to bottom: total input current of the converter, input currents of the interleaved coupled-inductor boost converters, and (b) primary current, secondary current, and leakage current in a phase of the interleaved coupled-inductor boost converters.


Fig. 4. (a) Gate pulses to the clamp boost converter and (b) inductor current of the clamp boost converter.


Fig. 5. Gate pulses to the interleaved coupled-inductor boost converters (10 V/div).


 Coupled-inductor boost converters can be interleaved to achieve high-step-up power conversion without extreme duty ratio operation while efficiently handling the high-input current. In a practical coupled-inductor boost converter, the switch is subjected to high voltage stress due to the leakage inductance present in the non ideal coupled inductor. The presented active clamp circuit, based on single boost converter, can successfully reduce the voltage stress of the switches close to the low-level voltage stress offered by an ideal coupled-inductor boost converter. The common clamp capacitor of this active-clamp circuit collects the leakage energies from all the coupled-inductor boost converters, and the boost converter recycles the leakage energies to the output. Detailed analysis of the operation and the performance of the proposed converter were presented in this paper. It has been found that with the switches of lower voltage rating, the recovered leakage energy, and the other benefits of an ideal coupled-inductor boost converter and interleaving, the converter can achieve high efficiency for high-step-up power conversion. A prototype of the converter was built and tested for validation of the operation and performance of the proposed converter. The experimental results agree with the analysis of the converter operation and the calculated efficiency of the converter.


 [1] L. Solero, A. Lidozzi, and J. A. Pomilio, “Design of multiple-input power converter for hybrid vehicles,” IEEE Trans. Power Electron., vol. 20, no. 5, pp. 107–116, Sep. 2005.

[2] A. A. Ferreira, J. A. Pomilio, G. Spiazzi, and de Araujo Silva, “Energy management fuzzy logic supervisory for electric vehicle power supplies system,” IEEE Trans. Power Electron., vol. 20, no. 1, pp. 107–115, Jan. 2008.

[3] A. Emadi, K. Rajashekara, S. S. Williamson, and S. M. Lukic, “Topological overview of hybrid electric and fuel cell vehicular power system architectures and configurations,” IEEE Trans. Veh. Technol., vol. 54, no. 3, pp. 763–770, May 2007.

[4] J. Bauman and M. Kazerani, “A comparative study of fuel cell-battery, fuel cell-ultracapacitor, and fuel cell-battery-ultracapacitor vehicles,” IEEE Trans. Veh. Technol., vol. 57, no. 2, pp. 760–769, Mar. 2008.

[5] Q. Zhao and F. C. Lee, “High-efficiency, high step-up DC–DC converters,” IEEE Trans. Power Electron., vol. 18, no. 1, pp. 65–73, Jan. 2003.