Analysis on voltage oscillation of a mid-frequency series resonant inverter for DRMP coils on J-TEXT

• The reason of high-voltage oscillation of a series resonant inverter for DRMP coils is analyzed.
• The condition or method for reduction of high-voltage oscillation is discussed.
• The considerations of dead time and switch frequency for reduction of high-voltage oscillation are discussed.

This paper deals with the voltage oscillation of an AC power supply for generating dynamic magnetic perturbation (DRMP) on J-TEXT. The power supply is a series resonant inverter with a matching transformer. It was noted that the high-voltage oscillation at transformer primary side is caused by an interaction between the line inductance and the stray capacitance of the matching transformer at switching transitions. In order to reduce the high-voltage oscillation and consider the requirement for soft-switching technique simultaneously, the switching frequency should be chosen properly by fine-tuning. The dead time should be chosen according to the relative size of minimum required dead time for protection and the optimal dead time.