Inverter Dead Time Compensation Method using On-Line tuning

Abstract

In this paper, a method for dead time voltage compensation is proposed. The dead time is a period for preventing short circuits in the semiconductor power devices incorporated in inverters. Owing to this dead time, an error occurs in the output voltage of the inverter with respect to the voltage command. To suppress this error, a dead time compensation signal is generally added to the voltage command. However, the accuracy of the above-mentioned compensation control may be reduced because of the switching characteristics of the power device, transmission delay of the switching command, and so on. In the proposed method, to achieve highly accurate dead time compensation, the waveform of the compensation signal is formed based on a circuit model that assumes a virtual capacitor is connected to the semiconductor power device in parallel. In addition, an automatic adjustment method was proposed for parameters such as the capacitance of the virtual capacitor. The proposed method is validated experimentally.