The Study On DC/AC Three Phase Soft Switching PWM For Inverter

The switch devices in the conventional PWM inverter turn on with high voltage and turn off with heavy current. It results in more consumed power, low frequency, and large volume, severe EMI etc.Based on external restrain devices, this paper will introduce Soft-switching technology into the inverter, which will solve the problem inside. Soft-switching technology produces zero voltage switching or zero current switching conditions by LC resonance, which decreases the switching loss, dv/dt, di/dt and EMI of switching devices.This paper focus on Soft-switching inverter, which includes resonant dc link inverter(RDCLI), active clamp resonant dc link inverter(ACRLI), parallel dc link inverter(PRDCLI). Analyzing the switching principle of these inverters, comparing the characteristics of the three kinds circuits and gaining the pulse wave of them. It was found that the switch loss, switching pulses decrease greatly.Based on this characteristic, this paper applies soft-switching inverter technology and PWM technology design the inverter circuit of V/F open control. The PWM integrate circuit chip and single chip micyoco are applied in this circuit. Some key circuits have been analyzed and gaining some run results.