A phase and an amplitude improving method includes performing a model establishing step, a phase compensating step, an amplitude compensating step and a compensation information generating step. The model establishing step includes establishing an inverter model. A voltage command is inputted to the inverter model to generate an actual voltage information. The voltage command includes a phase command information and an amplitude command information. The phase compensating step includes computing the phase command information and the actual voltage information to generate a compensating phase information. The amplitude compensating step includes computing the amplitude command information and the actual voltage information to generate a compensating amplitude information. The compensation information generating step includes generating a compensating voltage command. The compensating voltage command is inputted to the inverter model to generate a compensating actual voltage information. |