High frequency inverter and DC-DC converter with ZCS-ZVS mode

A family of single-ended current resonant high-frequency inverters (SECR-HF-INV) using static induction transistors (SITs) is proposed which enables operation in ZCS-ZVS (zero-current switching-zero-voltage switching) or ZCS modes to reduce the switching loss and noise. SECR-HF-INV in which only a small resonant inductance is connected in series with SIT to preform ZCS-ZVS operation is derived from the conventional single-ended voltage resonant type high frequency inverter. In the ZCS operation region of the SECR-HF-INV, the voltage stress is suppressed and no high voltage generates without the snubber. The ZCS technique is applied to the SECR-HF-link DC-DC power converter and the ZCS operation region is elucidated in the normalized μ-λ plane. From the results, the ZCS-ZVS operation region as the boundary between ZCS and no-ZCS is clarified. ZCS operation of the main active switch and quasi-ZCS-ZVS operation of the rectifying diode are investigated. It is shown that the SECR DC-DC converter enables one to operate with ZCS mode in the steady-state, even in the case when the ZCS mode is not guaranteed in the transient state