Saliency investigation of PM brushless AC motors for high-frequency carrier signal injection-based sensorless control

Machine saliency level is a critical concern for high frequency carrier signal injection-based sensorless control of permanent magnet brushless AC (BLAC) motors. To describe the machine saliency level during the whole operation range, machine incremental inductances are required in conventional concepts. To avoid it for machine saliency investigation, a simple experimental method is developed in this paper for practical application, which could easily obtain the machine saliency information without any machine parameters. Based on the measured machine saliency information, Sensorless Safety Operation Area (SSOA) can be obtained, which is in a good agreement with the calculation results. Experimental results confirm the effectiveness of proposed method.