A phase and amplitude improving method is proposed. The phase and amplitude improving method includes a model establishing step, a phase compensating step, an amplitude compensating step and a compensation information generating step. The model establishing step is performed to establish an inverter model corresponding to an inverter circuit. A voltage command is inputted to the inverter model to generate an actual voltage information. The phase compensating step is performed to compute a phase command information of the voltage command and the actual voltage information to generate a compensating phase information. The amplitude compensating step is performed to compute an amplitude command information of the voltage command and the actual voltage information to generate a compensating amplitude information. The compensation information generating step is performed to generate a compensating voltage command, and the compensating voltage command is inputted to the inverter model to generate a compensating actual voltage information. Thus, the phase and amplitude improving method of the present disclosure can decrease an error between the voltage command and the actual voltage information. |