Research on High-Frequency Square Wave Control for Sensorless Motor Drives

The rotor position information, which is typically obtained through encoders or rotating transformers, is relied upon by the traditional motor vector control system to achieve precise field-oriented control. Given considerations such as cost and installation position, sensorless vector control technology has emerged as a new research focus. The cost and algorithmic complexity of traditional sine wave injection motor control are relatively high. To address these issues, a sensorless control technique is introduced in this article, which utilizes high-frequency square wave signals for injection, departing from the conventional practice of employing sine wave injections. This effectively eliminates the need for filters in traditional control and significantly streamlines the process of signal processing for estimating rotor positions. The results of hardware testing experiments indicate that sensorless control, with the introduction of elevated-frequency rectangular waveforms, is more dynamic and easier to implement, achieving accurate motor speed control with small position errors.