三相四开关变换器直流侧分离电容电压不平衡,将降低其并网电能质量,缩短电解电容寿命。针对该问题,提出了一种直流侧分离电容电压均衡的模型预测功率控制策略。基于αβ两相静止坐标系分析电压矢量,建立功率预测模型。由于直流侧电容中点电压偏差值含有交流分量和直流分量,使用低通滤波器提取直流分量后计算功率补偿值,并计入给定功率,进行模型预测功率控制,实现直流侧分离电容电压均衡。该控制策略无需锁相环和PWM调制,易于实现。通过仿真和试验对其动、静态特性进行分析,验证了所提出控制策略的有效性和可行性。

The unbalanced capacitor voltage of three-phase four-switch converter reduces the grid-connected power quality and lifetime of the electrolytic capacitor. In order to balance the DC-link capacitor voltage, a model predictive power control strategy was proposed. Based on the analysis of the voltage vector in the αβtwo-phase stationary coordinate system, the power predictive model was established. As the DC-link midpoint voltage deviation contains the AC component and DC component, low-pass filter was used to extract the DC component to calculate the power compensation value. Then, the power compensation value was added to the reference power, the cost function to select the optimal voltage vector to achieve grid-connected power control and the capacitor voltage banlance was used. The control strategy does not require phase-locked loop or PWM modulation, and was easy to implement. The dynamic and static characteristics were analyzed by simulation and experiment, and the feasibility of the proposed control strategy were verified.

TN 624

国家自然科学基金项目(51607159)；河南省科技攻关项目(172102410068)；河南省高校科技创新人才支持计划(18HASTIT025)；青年骨干教师资助计划(2015GGJS-180)