Sensorless Control with Switching Frequency Square Wave Voltage Injection for SPMSM with Low Rotor Magnetic Anisotropy

High-frequency signal injection sensorless algorithms are widely studied and used for rotor angle estimation in PMSM at low speed or standstill. One of the main drawbacks such methods is acoustic noise connected to voltage injection. In order minimize this problem, it advisable increase frequency injected signal. Thus, many studies focus on square-wave switching frequency, which maximum theoretical frequency. Since these exploit magnetic anisotropy, relatively easy use them interior PMSMs, where anisotropy high. On contrary, hard surface have an almost symmetric rotor, although a still present. paper, algorithm with developed PMSMs. To signal-to-noise ratio, current oversampling exploited. The benefits technique demonstrated experimental results 2 Nm SPMSM.