Synchronous motor control device, compressor drive device, air-conditioner, and method for controlling synchronous motor

摘要

A synchronous motor control device equipped with a DC power source 1, an inverter main circuit 2, a three-phase synchronous motor 3 driven by converting the direct current from the DC power source 1 to an alternating current using the inverter main circuit 2, and an inverter control unit 6 to which an angular velocity command value, a phase current value from the three-phase synchronous motor 3, and a DC voltage value from the DC power source 1 are inputted, and which outputs a PWM signal for controlling the inverter main circuit 2, wherein the inverter control unit 6 is provided with: a PWM signal generation unit 10; a startup control unit 8 for outputting a startup voltage command value that corresponds to the phase current value to the PWM signal generation unit 10 at the time of startup; a regular control unit 13 for calculating a regular voltage command value at a time of regular operation by using a voltage equation, and outputting the same to the PWM signal generation unit; and a regular control parameter initial value calculation unit 12 for outputting a control parameter initial value for the regular control unit 13 to the regular control unit 13, in a manner such that the output voltage vector from the inverter main circuit 2 to the three-phase synchronous motor 3 is identical before and after switching, when switching from starting up to regular operation. Thus, stable startup is possible.