单相级联H桥整流器电压平衡与纹波抑制策略研究

Study on Voltage Balance and Ripple Suppression Strategy of Single-Phase Cascade H-bridge Rectifier

对传统单相级联H桥整流器主电路加以改进,增加了功率解耦桥臂,建立了数学模型,并对电压平衡和纹波抑制策略进行了研究。首先,整体回路采用双闭环控制,通过二阶广义积分方法优化了基波信号的提取方案;其次,对系统功率平衡关系进行推导,建立网侧电流和电容电压平方的一次关系模型,并引入可变比例环节,有效提升系统抵御参数变化的鲁棒性;然后,采用独立式Buck型有源功率解耦控制策略,通过运算实时分配解耦桥臂开关管占空比,设计自适应选频器分离二次纹波信号,实现对直流母线二次纹波电压脉动的抑制。最后,基于Matlab/Simulink软件进行试验验证,所提方法能够有效地解决电压平衡和二次纹波功率抑制问题。

The main circuit of the traditional single-phase cascade H-bridge rectifier is improved,the power decoupling arm is added,the mathematical model is established,and the voltage balance and ripple suppression strategies are studied.Firstly,the whole loop is controlled by double closed-loop,and the extraction scheme of fundamental signal is optimized by the second-order generalized integration method.Secondly,the power balance relationship of the system is derived,the primary relationship model of the grid-side current and the capacitance voltage squared is established,and the variable proportion link is introduced to effectively improve the robustness of the system to resist parameter changes.Then,the independent Buck-type active power decoupling control strategy is adopted,and the duty cycle of the decoupled bridge arm switch tube is distributed in real time by calculation,and an adaptive frequency selector is designed to separate the secondary ripple signal to realize the suppression of the secondary ripple voltage ripple of the DC bus.Finally,the experimental verification based on Matlab/Simulink software shows that the proposed method can effectively solve the problems of voltage balance and secondary ripple power suppression.