Method to enhance the short-circuit running reliability of current-controlled two-stage inversion power supply

On aviation and other high-reliablity required occasions, specific requirements of short-circuit running ability are put forward to the inversion power supply. As the inverter is running with short-circuit current which cannot decrease, and the switching frequency is at the maximum when using hysteretic current control because the output voltage is zero. Both conduction and switching dissipations of power switches are much greater than those of normal operation. This leads to overheating which is a major killer to the power switches. To enhance short-circuit running reliability, the traditional approach is to increase the switches´ power rating and the volume of heat sink, but its cost is greatly increased. In this study, a new method enhancing the short-circuit running reliability of current controlled two-stage inversion power supply is proposed. It can increase short-circuit running reliability effectively. What is more, the cost also decreases because of the non-increasing of both power rating of switches and the volume of heat sink. The key issues of this method are theoretically analysed in detail. A 200´W two-stage inversion power supply with a dual Buck inverter as its inverter part is made. The validity of this method is verified by its simulation and experimental results.