Patent ID: 7443120

Claim:
A field weakening vector controller which calculates a d-axis current command value so that the output voltage of a power converter which drives a permanent magnet synchronous motor may be a preset value, wherein: said filed weakening vector controller comprises a stabilization calculator, a d-axis current command calculator, a q-axis current command calculator, and a phase calculator; said d-axis current command calculator corrects the d-axis current command value using a difference between the d-axis current command value and the d-axis current detection value; said stabilization calculator calculates a product of a phase error or a sine signal of the phase error which is the difference between the reference axis of control calculated by said phase calculator and a reference axis of the motor, and the d-axis current command value or the d-axis current detection value; and said q-axis current command calculator corrects the q-axis current command value using the product.