采用参数辨识及新型主动阻尼控制的LCL滤波脉宽调制整流器

PWM Rectifier With LCL Filter Based on Parameter Identification and a New Active Damping Control

采用LCL滤波器的脉宽调制整流器一般需要检测电网电压、电流及直流母线电压,为抑制谐振还需检测交流滤波电容支路电压或电流。过多的传感器增加了整流器成本,且检测所得电网电压实际易受电网内感抗干扰,影响整流器稳定运行。首先提出一种基于电网参数辨识的虚拟磁链定向控制方法。在整流器启动之前,采用遗传算法辨识电网感抗、频率、幅值和初始相位角等参数,以获得虚拟磁链及其初值的精确观测。为抑制LCL滤波器谐振,提出一种通过一阶高通滤波器回馈整流器侧电流高频分量的新型有源阻尼控制方法,建立频域模型,分析高通滤波器参数对谐振抑制效果的影响。所提控制策略只需检测直流母线电压及整流器侧两相电流,省去了电网电压传感器及交流滤波电容支路电压或电流传感器。仿真和实验分析证实了该控制策略有效性。

To control pulse width modulation （PWM） rectifier with LCL filter, not only grid voltages, currents and DC bus voltage, but also voltages or currents on capacitor branch should be detected in order to eliminate resonance. So many sensors cause high cost of the rectifier. And because the detected power grid voltage contains influence of the actual impedance of the grid, the stability of the rectifier is affected. In this paper, a control strategy based on parameter identification of power and virtual flux oriented was studied. To achieve accurate virtual flux observation, considering the particular complexity of the LCL filter, before starting the rectifier, Genetic Algorithms was used to identify grid inductance, frequency, amplitude and initial phase ang!e. And for resonance problem of the LCL filter, a new active damping control method was proposed, which gave directly feedbacks of high. frequency component of the current on rectifier side through a first-order high-pass filter. The frequency domain model was set to analyze the high-pass filter parameters on the resonant inhibiting effect. This strategy only detected the DC bus voltage and the rectifier side of the two-phase current, eliminating power grid voltage sensors and voltage or current sensors on capacitive branch. Finally, simulation and experimental results prove the effectiveness of the proposed control strategy.