SPACE-VECTOR ANALYSIS AND MODULATION ISSUES OF PASSIVELY CLAMPED QUASI-RESONANT INVERTERS

The passively clamped quasi-resonant de-link (PCQRL) inverter basic to pology and other quasi-resonant inverters have been shown to be only p artially compatible with pulsewidth modulation (PWM), due to a minimum dwell time created by the clamping mode in the inverter operation. Th is paper addresses this kind of modulation nonlinearity, employing the space-vector approach as a modeling tool, closed-form expressions are obtained, defining the inverter linear modulation range in terms of t he dwell time and other inverter and load parameters and characteristi cs. An alternative implementation of the resonant snubber that elimina tes the low-order harmonics in the output voltages is presented. Exper imental and simulation results are presented to support the theoretica l analysis.