A Novel Zero-Voltage-Switching PWM Full Bridge Converter

A Novel Zero-Voltage-Switching PWM Full Bridge Converter

ABSTRACT

Introducing resonant inductance and clamping diodes into the full-bridge converter can eliminate the voltage oscillation across the rectifier diodes and increase the load range for zero-voltage-switching (ZVS) achievement. The resonant inductance is shorted and its current keeps constant when the clamping diode is conducting, and the clamping diode is hard turned-off, causing significant reverse recovery loss if the output filter inductance is relatively larger. This paper improves the full-bridge converter by introducing a reset winding in series with the resonant inductance to make the clamping diode current decay rapidly when it conducts. The reset winding not only reduces the conduction losses, but also makes the clamping diodes naturally turn-off and avoids the reverse recovery. The operation principle of the proposed converter is analyzed. The design of the turns ratio of transformer is discussed. A 1 kW prototype converter is built to verify the operation principle and the experimental results are also demonstrated.

KEYWORDS

      1.  Clamping diodes

        2.    Full bridge converter

        3.    Reset winding

        4.    Zero-voltage-switching (ZVS)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1. Proposed ZVS PWM full bridge converter.(a) T_r_ _lag  type. (b) T_r_ _lead  type.

CONCLUSION:

A new ZVS PWM full-bridge converter is proposed in this   paper, it employs an additional reset winding to make the clamping diode current decay rapidly when the clamping diode conducts, thus the conduction losses of the clamping diodes, the leading switches and the resonant inductance are reduced and the conversion efficiency can be increased. In the meanwhile, the clamping diodes can be turned off naturally without reverse recovery over the whole input voltage range, and the output filter inductance can be designed to be large to obtain small current ripple, leading to reduced filter capacitance. Compared with the traditional full bridge converter [14]–[16], the proposed circuit provides another simple and effective approach to avoid the reverse recovery of the clamping diodes. The operation principle, features and comparisons are illustrated. The Experimental results from the prototype are shown to verify the feasibility of the proposed converter.

REFERENCES:

[1] X. Ruan and Y. Yan, “Soft-switching techniques for pwm full bridge converters,” in Proc. IEEE Power Electron. Spec. Conf. (PESC’00), 2000, pp. 634–639.

[2] D. M. Sable and F. C. Lee, “The operation of a full-Bridge, zero voltage- switched pwm converter,” in Proc. Virginia Power Electron. Center (VPEC’89), 1989, pp. 92–97.

[3] J. A. Sabate, V. Vlatkovic, R. B. Ridley, F. C. Lee, and B. H. Cho, “Design considerations for high-voltage, high power full-bridge zero voltage- switched pwm converter,” in Proc. IEEE Appl. Power Electron. Conf. (APEC’90), 1990, pp. 275–284.

[4] G. C. Hua, F. C. Lee, and M. M. Jovanovic, “An improved zero-voltage-switched pwm converter using a saturable inductor,” in Proc. IEEE Power Electron. Spec. Conf. (PESC’91), 1991, pp. 189–194.