A Control Strategy for Inverter Type High Voltage Power Supply for NBI

An inverter type high voltage power supply has been designed for the acceleration of ITER NBI system. This type of power supply can regulate the output voltage rapidly by the duty cycle modulation of the inverter switches. However, when the duty cycle is too small, the output ripple will be lager. This paper studies a new control strategy of the power supply, the output voltage is regulated by inverter duty cycle, also by adjusting the DC-link voltage. The front rectifier of this power supply is constructed by thyristor bridges, while the inverter is a three phase three level inverter. Control system for this power supply is designed in this paper. Simulation results is given, and the results demonstrate that the topology and control strategy can limit the voltage ripple while maintain the rapid voltage response.