Inverter Nonlinearity Compensation of Discontinuous PWM Considering Voltage Drop of Power Semiconductor and Dead Time Effect

Abstract

This paper proposes a method to compensate for the nonlinearity of an inverter, which generally exists regardless of PWM schemes. The nonlinearity originates from the on-state voltage drop of the semiconductor switches and the dead time effect. The effect of the dead time to the control of the inverter has a strong dependency on PWM scheme because the dead time effects occur only at the switching instant of the inverter and the switching is solely decided by PWM scheme. Thus, for the accurate compensation of the nonlinearity, the effect of the dead time should be analyzed with different PWM schemes. The proposed method considers the difference of dead time effect according to different PWM schemes, namely Continuous PWM and Discontinuous PWM. In addition, to implement the proposed method, a new nonlinearity effect identification is introduced, which can separate the on-state voltage drop from the dead-time effect. Several experimental tests are carried out to verify the validity of the proposed method.