In this paper, a new single soft switched forward converter with a self driven synchronous rectification (SDSR) is introduced. In the proposed converter, a soft switching condition (ZCS turn on and ZVS turn off) is provided for the switch, by an auxiliary circuit without any extra switch. In additional, this auxiliary circuit does not impose high voltage or current stresses on the converter. Since the proposed converter uses SDSR to reduce conductive loss of output rectifier, the rectifier switches are switched under soft switching condition. So, the conductive and switching losses on the converter reduce considerably. Also, implementing control circuit of this converter is very simple, due to the self-driven method employed in driving synchronous rectification and the converter is controlled by pulse width modulation (PWM). The experimental results of the proposed converter are presented to confirm the theoretical analysis.

This paper deals with a simple and practical power loss analysis simulator, which can actually estimate the total power losses of three phase voltage-fed Auxiliary resonant commutation pole snubber assisted soft switching inverter as well as hard-switching inverter. In order to estimate the switching power losses and conduction power losses of switching semiconductor power devices (IGBTs), which are incorporated into the inverters, the proposed practical simulator is making use of feasible switching power loss data tables and conduction power loss data tables, which are accumulated from the measured voltage and current operating waveforms of power semiconductor switching devices. The practical effectiveness of feasible simulation technique and power loss evaluations for power electronic conversion circuits and systems are confirmed by the simulation and experimental results basis under the conditions of soft switching and hard switching sinusoidal PWM schemes.

This paper describes the circuit design procedure of the zero-current soft switching (ZCS) high frequency inverter for induction heating uses. Its output power can be regulated from its maximum to minimum by the instantaneous current vector control scheme using phase shift control between switching units at a fixed frequency. In addition, it can be safely operated since no extraordinarily high voltage or current results even at a short-circuit period at the load. Also, its overall efficiency reaches 90%. The detailed load and frequency characteristics of the inverter are elucidated by the computer-aided simulation. Then, the circuit design procedure is presented, and practical numerical examples are obtained according to this procedure which reveal that the inverter is highly practical and the design procedure is effective. The trial inverters yielding 2 kW or 4 kW were actually prepared. The observed values of the voltages and currents of the inverters were found to be in good agreement with the calculated ones. These facts certificate the validity of the proposed design procedure.