A Resonant DC-Link Inverter and Its Voltage Compensation Strategy

In order to solve the output voltage loss problem caused by the zero-voltage notch of resonant dc-link (RDCL) inverter and improve system efficiency, this article proposes an RDCL inverter and its voltage compensation method. The topology of this auxiliary circuit is simpler, and the resonant current is separated from the load current by parallel auxiliary switch, which reduces the current stress of the main switches. At the same time, the method is based on the conventional sinusoidal pulsewidth modulation (SPWM); this method first calculates the operation time of the auxiliary circuit based on the magnitude of the phase current, second adjusts the position of the triangular carrier according to the calculation results, and finally generates the driving signals for early turn-on and delayed turn-off, which solves the voltage loss problem and improves the voltage utilization, the output voltage is the same as that of the ideal SPWM. The working principle, parameter design conditions, and voltage compensation method are analyzed in detail in the article. Finally, a 5-kW/16 kHz prototype is created with insulated gate bipolar transistor (IGBT) as switching device, which verifies the novel resonant dc-link inverter and its modulation strategy is effective.