A variable frequency soft commutated voltage source inverter delivering sinusoidal waveforms

A comparison of the rugged soft commutated pulse width modulation inverter (RSCPI) and the soft switched resonant pole inverter (SSRPI) is presented. These two converters have been introduced as alternatives to the resonant DC link inverter (RDCLI) and they are intended for use in variable speed drives. Based on the zero-voltage switching technique, both converters can operate at high switching frequency. A well-known pulse width modulation (PWM) strategy is adopted for the RSCPI. The performance results are compared with those obtained from the SSRPI using adaptive hysteresis control. This control is especially effective for- reducing conduction losses. It is shown that the RSCPI has reliability due to its inherent overload protection, but the SSRPI configuration is more practical in the sense that it reduces the losses and increases the system efficiency.<>