基于预测功率模型的级联整流器均压新方法

New Voltage Balancing Method for Cascaded Rectifier Based on Predictive Power Model

基于二阶广义积分构造虚拟电压和电流正交分量来建立dq旋转坐标系,以有功和无功占空比为控制对象,结合瞬时功率理论推导出预测功率模型,构造级联H桥整流器主控制系统。然后,针对其直流侧电压不平衡问题,提出了一种新型均压控制策略,即通过电压平衡控制器计算得出耦合效应目标函数取得最小值时有功占空比的修改量,重新构造了各H桥模块有功占空比,调节有功功率分配,从而在保持各H桥模块直流侧电压平衡的基础上,减小了电压平衡控制器与主控制系统之间的耦合效应。仿真和实验结果证明了所提方法的正确性和可行性。

The dq synchronous system was built by constructing virtual orthogonal voltage and current based on second order generalized integrator. The predictive power model was derived to construct main control system of cascaded H-bridge rectifier combining the instantaneous power theory, which took the duty cycle of active and reactive power as control object. Then, a new voltage balancing control strategy was proposed dealing with the problem of DC voltage imbalance in cascaded H-bridge rectifier. The modification of active power was obtained by the voltage balance controller when the objective function of coupling effect achieves minimum and the active power was distributed by reconstructing the duty cycle of active power in each modular, which eliminated the coupling effect between the voltage balance controller and the main control system on the basis of ensuring the DC voltage balance. The correctness and effectiveness of the proposed method was verified by simulation and experimental results.