Predictive control with variable amplitude of voltage vector of interior PMSM direct torque control system

Based on stator flux and torque's expressions of interior permanent magnet synchronous motor (PMSM) direct torque control (DTC) system in stator flux frame, voltage vector with variable amplitude and fixed angle is used as candidate output voltage vector. The amplitude of stator flux and torque at next sampling point after applying voltage vector with different amplitude are obtained. A one-step selection algorithm is established based on the cost function of stator flux and torque's errors, which can choose voltage vector to minimize the cost function. More candidate voltage vectors will lead to better control performance, but it will cause heavier calculation burden. In this paper, control performances of interior PMSM DTC system are compared using 10 different methods to divide voltage vector. Considering control performance and calculation burden, dividing voltage vector into five equal parts to get the aggravate of 5 candidate voltage vectors is an ideal way. And system performance tends to be stable.