Double Integral Sliding Mode Sensorless FOC For Improved Dynamics in IPMSM Driven Refrigerators

Considering the requirement of improved dynamics and noise-free operation in domestic refrigeration systems, this work proposes a double integral sliding mode vector control (DISMVC) strategy for the sensorless operation of interior permanent magnet synchronous motor (IPMSM). Addressing the peak overshoots due to the limited operational range in the conventional control strategies, the proposed DISMVC offers smooth control over the extended range of speed variations. The proposed double-integral sliding surface ensures instantaneous speed reference tracking and reduced peak overshoots. Further, to handle the chattering phenomena in conventional sliding mode control, a sigmoidal function is introduced instead of the traditional signum function in coherence with the double integral sliding mode control. The proposed control, along with the sigmoidal function, significantly reduces the current chattering and, thereby, torque ripple helps minimize the vibrational noise in refrigeration systems. The performance of the proposed sensorless IPMSM drive is validated through extensive MATLAB/Simulink simulations, followed by experimental testing on a refrigeration setup to demonstrate its effectiveness in real-world applications.