Performance Analysis of Field Oriented Control Under Temperature Variations in a Synchronous Motor

This study investigates the effects of temperature variations on the dynamic performance of a field oriented control (FOC) in a synchronous motor. A typical FOC with torque optimization using maximum torque per ampere (MTPA) and maximum torque per volt (MTPV), space-vector modulation (SVM), and feedforward estimator, with typical gain tuning based on motor parameters, was experimentally evaluated at multiple operating points, including the field-weakening region. Although heat-induced changes in parameters have been quanti-fied, experimental research on their specific effect on controller performance is still scarce. Most existing studies limit their focus to only a few operational points and often disregard the full torque-speed map, notably overlooking the critical field-weakening region. Some studies even propose that these variations are negligible for control. The performance of the FOC was evaluated using the rise time, settling time, and overshoot percentage in each operation point jump. The results revealed that higher temperatures lead to increased rise time and reduced overshoot in the constant torque region, while both decrease in the field-weakening region. A 45°C variation led to rise time and overshoot changes of 39% and 50.89% in the constant torque region, and 21.5% and 99.56% in the field-weakening region.