Suppression of Velocity Pulsations with Resonant Controllers in Sensorless Vector Control of Permanent Magnet Synchronous Motors

This paper proposes control methods to suppress periodic velocity pulsations caused by load torque in a rotary compressor during sensorless field-oriented control (FOC) of an interior permanent magnet synchronous motor (IPMSM). A primary contribution of this work is the introduction of two types of resonant controllers into the speed control system. These controllers effectively mitigate the periodic velocity pulsations caused by the fundamental and second harmonic components of the compressor's load torque. Stability analysis, where the dominant poles of the proposed sensorless control systems are determined at various speeds, demonstrates that the systems are internally stable over a wide speed range. Experimental results validate the suggested systems' effectiveness in suppressing the periodic velocity pulsations by evaluating both steady-state and transient responses.