电流源型PWM整流器带容性负载的解耦控制方法

Decoupling Control Strategy of Current-Source PWM Rectifier with Capacitive Load

应用于不间断电源(UPS)时,三相电流源型整流器(CSR)因其直流输出端存在大电容而使得数学模型的阶数提高,增加了控制器的设计难度。针对带电容性负载的PWM型CSR建立了dq旋转坐标系中的数学模型,通过将d轴定向于交流滤波电容电压矢量,使得数学模型简化为相互解耦的直流侧和交流侧模型,进而可实现直流侧和交流侧的独立控制。进一步提出了在直流侧采用状态反馈控制来稳定直流母线电压,在交流侧引入虚拟阻抗进行网侧电流有源阻尼的控制方法,消除直流侧和交流侧之间由PWM调制过程所产生的相互影响,实现了直流侧和交流侧的解耦控制。基于40k V·A的UPS仿真和样机实验结果表明,该方法具有良好的动态性能和稳态性能。

In the uninterruptible power supply （UPS） system, the bulk capacitors installed in the DC bus of current-source PWM rectifier （CSR） lead to a higher order of system model, which adds complexity in the system control. This paper establishes a model for CSR with the capacitive load under dq rotation coordinate. With the dq coordinate to the AC side capacity voltage vector, the proposed model is simplified into DC side model and AC side model, and then the independent control of DC side and AC side can be realized. This paper further proposes the state feedback control in DC side and the active damping control in AC side, which can eliminate the interaction between DC side and AC side. Thus decoupling control of DC side and AC side can be realized. Experimental results for 40kV.A UPS prototype verify the proposed control strategy.