Using High-Control-Bandwidth FPGA and SiC Inverters to Enhance High-Frequency Injection Sensorless Control in Interior Permanent Magnet Synchronous Machine

A high-frequency injection (HFI) sensorless control for interior permanent magnet synchronous motors with enhanced precision and widened speed range is proposed in this paper. The injection frequency reaches up to 2 kHz under a 50~100 kHz silicon carbide (SiC)-based three-phase inverter. In addition to the high switching frequency, the field-programmable gate array (FPGA) is utilized to achieve high control bandwidth (>200 kHz) when implementing the field-oriented control algorithm. The benefits of high switching frequency and high control bandwidth in senseless controls are explained theoretically, i.e., leaving enough room for the injection frequency by using SiC while tuning down the noise-to-signal ratio by using the FPGA. Experimental results verified that such manners improved the position estimation and lifted the injection frequency effectively, which further allows us to widen the motor speed range under the HFI sensorless control from 0 to 500 r/min with the conventional Si+DSP design to 0~1200 r/min with the proposed SiC+FPGA.