Modeling and Digital Control of 100kV/50kW High Voltage Power Supply based on PPSS-LCC for X-ray generator

For the high-voltage (HV) DC power supply feeding X-ray generator, LCC resonant converter with primary-parallel-secondary-series (PPSS) configuration is commonly adopted due to low switching losses and high output capability. In this paper, an analytical state-space model of the PPSS-LCC is derived with the diode-rectified output capacitor filter taken into consideration. Based on extended describing function (EDF) method, the high-order non-linear system is linearized by small-signal approximation for frequency control, and steady-state working point is solved. Simulation and experiments on a practical 100kV-50kW digital controlled PPSS-LCC serving an X-ray generator are carried out. The operation of the PPSS-LCC system on varying loads verifies the effectiveness of proposed model and control scheme.