An improved maximum torque control with DC link voltage disturbance

In this paper, an improved maximum torque control strategy is presented for IPMSM drives under the condition of VSI dc link voltage disturbance. Voltage disturbance can not be avoided in IPMSM drives especially for battery-supplied electric-driven application. As the result, the deterioration of control performance will happen, and even the system stability will be threatened in field-weakening region. Although this disturbance can be resisted by introducing the dc link voltage in calculation of SVPWM normally, the method also reduces the robust and stability in the whole control region. In view of the problem, by introducing the virtual voltage defined as ratio of maximum voltage and electrical angle frequency, the currents command are obtained based on the virtual limit described by virtual voltage, so as to achieve accuracy torque control with dc voltage disturbance in constant torque limit region and field-weaken region. Based on the proposed method, the online rapid algorithm is given by using the second order least square error approximation method. The simulation control system is constructed to verify the proposed control strategy. And the results have been found in good agreement with theoretical analysis.