New low‐noise sensorless control strategy for permanent magnet synchronous motor drives based on variable‐frequency voltage signal injection

Abstract This paper proposes a new low‐noise sensorless control strategy for the permanent magnet synchronous motor (PMSM) drives to tackle audible noise caused by high‐frequency injection method. The traditional noise reduction methods face limitation in improving estimated accuracy of rotor position due to the signal delay with fixed frequency signal. To overcome this issue, a low‐noise sensorless control strategy is developed, which consists of two parts. First, with the injection of the proposed variable‐frequency voltage signal, significant noise reduction can be achieved due to its characteristics of multi‐frequency switching and multi‐modal amplitude tuning. Secondly, a delayed effects‐aware demodulated signal is designed to reduce the impact of system delay, which can further improve the estimation accuracy of rotor position. As a result, the proposed low‐noise sensorless control scheme can suppress audible noise and further improve position estimation accuracy. Also, the steady‐state and dynamic performances of the motor drive system can be enhanced. Finally, comparative experiments under steady‐state and dynamic conditions demonstrate the superiority of the proposed method in PMSM.