三相电流型整流器及其控制策略的研究

Study on three-phase current rectifier and its control strategy

分析了用于蓄电池充电的电流型整流器(Current Source Rectifier,CSR)主电路拓扑结构,采用了三值逻辑空间矢量调制,建立了dq坐标系下三相CSR多环路直接电流控制的线性大信号数学模型。针对模型中d、q轴的耦合影响问题,采用了一种前馈解耦控制方法,消除了系统的非线性、耦合特性,从而简化了控制环路的设计。其次,针对LC滤波器的谐振问题,引入了一种基于电容电压反馈的有源阻尼控制策略,Bode图分析结果验证了控制策略的有效性。研究结果表明,三相CSR直流侧输出电流、交流侧输入电流均能保证快速动态响响应,网侧电压电流实现了单位功率因数,同时电流内环引入的前馈有源阻尼控制有效抑制了LC滤波器的谐振,使网侧电流的THD值由4.55%降到了2.17%。

Aiming at topology of three-phase current source PWM rectifier which is used for battery charging,a tri-logic space vector modulation technology is adopt to establish a linear large signal mathematic model with three-phase CSR multi closed-loop direct current control method under dq coordinate system.For the coupling effect of d axis and q axis in model,a feed-forward decoupling control method is used to eliminate the non-linearity and coupling characteristic,thus the design control loop is simplified.In view of the resonance of LC filter,the passive damping control strategy is introduced,which is based on the series resistance of capacitor voltage feedback,and the analysis result of Bode plot verifies the effectiveness of the proposed control strategy.Finally,simulation and experimental results demonstrate that the DC side output current and AC side output current of three-phase CSR can guarantee the fast dynamic response,and voltage current of network side achieves the unity power factor.Meanwhile,the feed-forward active damping control introduced by current inner-loop effectively suppresses the resonance of LC filter,and the THD value of network side current is reduced from 4.55%to 2.17%.