PWM/PDM dual mode controlled soft switching multi resonant high-frequency inverter

In this paper, a novel type auxiliary active resonant capacitor snubber assisted zero current soft switching pulse modulation single-ended push pull (SEPP) series load resonant inverter with two auxiliary resonant lossless inductor snubbers is proposed for consumer high-frequency induction heating (IH) appliances. Its operating principle in steady state is described by using each mode equivalent circuits. The new multi resonant high-frequency inverter can regulate its output power under a condition of a constant frequency zero current soft switching (ZCS) commutation principle on the basis of asymmetrical PWM control scheme. The consumer brand-new IH products using proposed ZCS-PWM series load resonant SEPP high-frequency inverter is evaluated and discussed as compared with conventional high-frequency inverter on the basis of experimental results. In order to extend ZCS operation ranges under a low power setting PWM, the pulse density modulation (PDM) strategy is demonstrated for high frequency multi resonant inverter. Its practical effectiveness is substantially proved from an application point of view.