A PWM Method of H-Bridge Converter With Temperature Rise Balancing and Minimization Based on Periodically Alternating Employment of Power Devices

Aiming at the temperature rise and thermal control issues of power devices in H-bridge converters under conventional pulsewidth modulation (PWM) methods, a novel PWM method of H-bridge converter with temperature rise balancing and minimization based on periodically alternating employment of power devices is proposed. In the proposed method, two novel operation mechanisms of power devices are alternately applied into the eight regions with the identical and opposite polarities of reference voltage and input current, which are composed of two fundamental frequency periods. All active switches and antiparallel diodes in H-bridge converters are made to work alternately in these eight regions, each of them is designed to keep in
on
-state in one region, operate in switching state in another two regions, and inactive in the left other five regions. This way, the power dissipation and temperature rise of all the devices are balanced and minimized, and H-bridge converters no longer suffer from the dead-time effect on current quality and dc-bus voltage utilization. The implementation strategy of the proposed modulation method is discussed in detail. Simulation and experimental results are presented that verify the effectiveness of the proposed method and the corresponding implementation strategy at different operating points.