An Active DC-Link Stabilization Strategy for Permanent Magnet Synchronous Motor Drive System Based on Inverter Voltage Compensation

Dc-link oscillation in electromechanical equipment drive system with film capacitor is a common problem when system impedance mismatch. For this problem, an inverter voltage compensation (IVC) strategy is proposed in this article to suppresses the oscillation of dc-link voltage. This method improves the motor input impedance by designing a damping compensation link so that the input and output impedances of the system can meet the stability conditions. It injects the damping signal into the inverter reference voltage of PWM modulation, which avoids the influence of current loop bandwidth and does not directly affect the motor speed or motor current. Moreover, the compensation impedance of this method is related to the motor voltage, which can compensate system damping dynamically according to the motor operating conditions, and the effect of the compensation link on the motor dynamic performance is reduced. Furthermore, the selection of compensation coefficients in this method is more intuitive and it simplifies the system design. Finally, experimental results demonstrate the effectiveness of the proposed method after building an experimental platform.