Novel Compensation Method for Current Distortion in IPMSM With PWM Carrier-Synchronized Voltage Injection

A high-frequency signal voltage injection method synchronized with the carrier wave of pulse-width modulation (PWM) can be used to estimate the rotor position of interior permanent magnet synchronous motors (IPMSM) by the accompanying high-frequency current. In the signal voltage injection method, the sampled current differs from the actual instantaneous current at the instance of switching. However, the inverter output voltage error strongly depends on the output current amplitude and polarity. In this article, we propose a method to compensate for the inverter output voltage error in each half of the PWM carrier period. Moreover, a technique for estimating the instantaneous current values based on the mathematical model of IPMSMs ensures that the proposed method can be combined with the signal voltage injection method. The proposed method was verified experimentally, and it resulted in a reduction in the low-order current distortion even when the output current has a large current ripple.