Voltage Clamp Circuits for a Power MOSFET PWM Inverter

Power MOSFETs are fast-switching devices suitable for high-frequency operations. However, high-speed switching and circuit inductance may cause voltage spikes to appear across the device and damage it. Three types of voltage clamp circuits that can be used with power MOSFETs are considered, and their essential features and characteristics are studied. The different modes of operation with these clamp circuits are discussed, and the design equations to determine these parameters in each clamp circuit are presented. The losses in the three clamp circuits are evaluated and compared. One clamp circuit is shown to offer outstanding advantages and is found to be suitable for high-frequency applications such as PWM inverters.