A current clamping circuit for a PWM series resonant DC link power converter

This paper presents a PWM current clamping circuit for improving a series resonant DC link converter. This circuit is capable of reducing current peaks to about 1.2-1.4 times the DC bias current. When desired, resonant transition creates notches in the DC link current, allowing the converter´s switches to synchronize with external PWM strategy. A regulated DC current source may be obtained-by using a conventional rectifier source-to feed a DC load or a current source inverter. The phase plane approach makes it easy to understand the operation, control and design procedure of the circuit. Another topology is derived and its features compared to the first circuit. Simulation results for the simplified circuit and for a three-phase induction motor driven by such an inverter are presented. Moreover, the principle is corroborated by experimental results