New Method of Vector Control in PMSM Motors

The paper introduces a new method for vector control of PMSM (Permanent Magnet Synchronous Motor) motors called theta-FOC. This method combines the advantages of simple sinusoidal control and Field Oriented Control (FOC). The paper proposes introducing an additional parameter that determines the electrical angle between the motor’s voltage space vector and rotor magnetic flux axis. The classical Field Oriented Control was modified to reduce the number of necessary calculations. The proposed method allows for decoupling the calculations from the cyclic PWM (Pulse Width Modulation) signal, enabling calculations to be performed at a frequency different from PWM. This results in the possibility of achieving a higher frequency of the PWM signal. Additionally, the proposed method minimizes the influence of deviation between the actual PWM voltage and the voltage command generated from the controller at high PWM frequencies, leading to better operation of the system in terms of field weakening. This method has been tested under typical operating conditions and has performed similarly to the FOC method, but with a reduced number of calculations, and therefore reduced control time.