A DSP Based Digital Control Strategy for ZVS Bidirectional Buck+Boost Converter

ABSTRACT:

 The non-isolated and bidirectional DC-DC converters are the most famous topology for low or medium power of the hybrid electric vehicle (HEV) or fuel cell vehicle (FCV) applications. These type of converters have the benefit of simple circuit topology, and bidirectional flows, zero-voltage switching (ZVS), and high efficiency, and high power density.

The turned-on ZVS for all MOSFETs is reach by the negative offset of the inductor current at the beginning and the end of each switching duration. To do this, the converter want a involved switching method which is chosen to be implemented by the digital signal processing (DSP) . This paper now the digital implementation of the switching design to provide the ZVS condition for such converter. A 5kW prototype is implement to verify the capability of such control scheme.

KEYWORDS:

  1. DC-DC converter
  2. Bidirectional converter
  3. Digital control
  4. Phase shift control

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig1. Bidirectional dc dc converter

EXPECTED SIMULATION RESULTS:

 Fig. 2. Inductor current waveforms of (a) boost mode and (b) buck mode

Fig. 3. ZVS turn on of switch S1

Fig. 4. Overall efficiency of both boost and buck operating modes

 CONCLUSION:

 A DSP located digital control method because the bidirectional DC-DC converter is prepared in this paper. The new control method produce a negative inductor current at the beginning of each pulse period that, in conjunction with just the parasitic MOSFET output capacitances but no additional element, admit ZVS with the full voltage and load range.

The DSP chip TMS320F28035 from Texas tool is employed to do this control algorithm. The experimental results not only show the ZVS because four switches but also produce an excellent overall efficiency at least 96% at the power range.

REFERENCES:

 [1] S. S. Williamson, S. M. Lukic, and A. Emadi, “Comprehensive drive train efficiency analysis of hybrid electric and fuel cell vehicles based on motor controller efficiency modeling,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 730-740, May 2006.

[2] K. Wang, C. Y. Lin, L. Zhu, D. Qu, F. C. Lee, and J. Lai, “Bidirectional dc to dc converters for fuel cell systems,” in Conf. Rec. 1998 IEEE Workshop Power Electronics in Transportation, pp. 47-51.

[3] A. Emadi, S. S. Williamson, and A. Khaligh, “Power electronics intensive solutions for advanced electric, hybrid electric, and fuel cell vehicular power systems,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 567-577, May 2006.

[4] D. Patel Ankita, “Analysis of bidirectional Buck-Boost converter by using PWM control scheme,” ISSN: 2321-9939, Electronics and Communication, Marwadi Education Foundation Group of Institute, Rajkot, India.

[5] Texas Instruments, “Modeling of bidirectional Buck/Boost converter for digital control using C2000 microcontroller,” Application report SPRABX5, January 2015.

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