Three-phase synchronous motor control device, three-phase synchronous motor drive system using the same, integrated motor system, pump system, compressor system, and three-phase synchronous motor control method

摘要

PROBLEM TO BE SOLVED: To provide a drive system of a synchronous motor which allows for stable driving from a very low speed area near zero speed by adjusting the individual difference of each motor, in phase estimation means used for phase estimation by detecting a variation in the neutral point potential, caused by unbalance in the three-phase inductance of a three-phase synchronous motor.SOLUTION: A drive system of a three-phase synchronous motor includes two phase estimation means, i.e., a first phase estimation means based on the neutral point potential and second phase estimation means based on the speed induced voltage, and phase correction means for storing the phase difference between two phase estimation means in a high speed area, and correcting the output from the first phase estimation means in low speed area by using the phase difference thus stored.