Average current mode control of high voltage DC power supply for pulsed load application

High voltage power supplies with pulse load (125 kHz and 10 % duty cycle) are investigated which are of interest for applications like radar power supplies with an output voltage of 22 kV. The performance specifications with this type of power supplies are very stringent demanding tight regulation (<0.01 %) and high efficiency (>85 %). This paper proposes a methodology to tackle the problems associated with this type of application. A phase-modulated series resonant converter with ZVS is used as the power converter. Average value of the rectified tank current is controlled to regulate the output voltage. Synchronization of converter switching with load pulses enables the converter to switch at half the load switching frequency. Low switching frequency helps in ensuring safety of HV transformer insulation and reduction of losses due to skin & proximity effect. Average current mode control gives excellent dynamic response with simple closed loop design.