PDM and PSM Hybrid Power Control of a Series-Resonant Inverter for Induction Heating Applications

This paper presents a high-frequency series-resonant inverter for induction heating applications, which is characterized by the pulse-density-modulation (PDM) and phase-shift-modulation (PSM) hybrid power control strategy. The inverter is kept to work at load resonant state for all load conditions and achieves zero-current-switching or zero-voltage-switching (ZCS ZVS) for switches of the inverter. Compared with PDM only schemed inverters, the PDM/PSM hybrid control schemed inverters present many advantages, such as: more steady output current, continuous power regulation, and operating in continuous current mode (CCM); When compared with PSM only schemed inverters, they achieve smaller phase-shift as well as hardly any distortion in output current. Even working under light load status, the inverter can realize quasisinusoid output current waveform with less fluctuation in peak value