Simplified predictive torque control for permanent magnet synchronous motor with discrete duty cycle control

Abstract

Here, a simplified predictive torque control strategy based on discrete duty cycle technology is proposed for the voltage source inverter permanent magnet synchronous motor drive system. Combining the discrete duty cycle technology, the candidate vectors are synthesised by two adjacent active vectors and zero vectors, and meanwhile, the duty cycles of the two adjacent active vectors and zero vectors are generated directly. Afterwards, an extended control set is constructed to improve the control accuracy of torque and flux. An inverted triangular matrix is constructed to store the duty cycle information, which corresponds to the row and column number of the elements. Also, the inverted triangle matrix is divided into three subregions according to the value of duty ratios. A cost function containing only the stator voltage vector error term is constructed and based on the geometric position of the reference voltage vector, the target region in the inverted triangle matrix is determined and the optimal vector is selected. So, the optimal vector prediction process and the duty cycle calculation process are combined into one, reducing the complexity of obtaining the optimal vector. Finally, the feasibility and effectiveness of the proposed algorithm are verified by experiments.