Generalized Predictive dc-Link Voltage Control for Grid-Connected Converter

The main function of the grid-connected converter in many applications is to control the dc-link voltage with high performance, i.e., strong disturbance rejection capability and good dynamic response. Take the grid-connected pulsewidth modulation (PWM) rectifier of a motor drive system as an example, good disturbance rejection capability is essential for the dc-link voltage control to address the varying loads on the motor side, and the dynamic process of the dc-link voltage control is preferred to be fast and overshoot-free, so as to adaptively adjust the dc-link voltage according to the motor speed and reduce the switching losses. However, the performance of the conventional proportional-integral (PI)-based dc-link voltage control is not always satisfying and can be further improved. In this article, the generalized predictive control (GPC) method is applied to the dc-link voltage control of a grid-connected converter for the first time, which can provide both good disturbance rejection capability and satisfying dynamic performance. Moreover, stability analysis of the proposed GPC-based dc-link voltage control strategy is theoretically studied, and a parameter tuning guideline is provided. The effectiveness and advantages of the proposed method are validated with experimental results.