PWM strategy for high frequency carrier inverters eliminating current clamps during switching dead-time

The switching dead time to protect the inverter main transistors from the arm shortage is investigated. The dead time causes not only waveform distortion, but also zero clamping phenomena. The zero clamping phenomena increase as the switching frequency increases. The inductance model was used to clarify the mechanism of the zero-clamping phenomena, and the dependencies of the phenomena on dead time and load power factor were investigated. A pulse width modulation (PWM) strategy to avoid the phenomena is proposed. The new PWM strategy is combined with the split-zero-vector method. The control scheme is discussed in detail, and experimental results are presented.<>