Simple Current Phase Control for Current Sensor-less Sinusoidal Drive System of Permanent Magnet Synchronous Motor with Low-resolution Position Sensor

Abstract

Recently, the sinusoidal drive of a permanent magnet synchronous motor has been actively researched because of its low noise and low vibration. Moreover, the sinusoidal drive system which uses only a low-resolution position sensor without utilizing the current sensor is researched. This paper proposes the method for deciding the lead angle of the impressed voltage by an easy expression for current sensor-less sinusoidal drive system of a permanent magnet synchronous motor with a low-resolution position sensor. The method is a technique for indirectly controlling the current phase without the dq axis transformation. First, the control method of adjusting the current of d axis to almost 0 and the control method of the weakening magnetic flux were shown. And, the methods were examined in numerical analyses. Next, the effectiveness of the proposed phase control method was verified using an actual motor. In the control method of adjusting the d-axis current to almost 0, the locus of the current vector was confirmed and an excellent transient response for controlling the current of d axis was obtained. Moreover, it was confirmed that the increase of applied voltage was controlled and the range of the drive had expanded in the method of the flux-weakening control.