一种无谐波检测的三相并网逆变器谐波灵活控制方法

为了简化三相并网逆变器的谐波补偿控制,同时提高并网逆变器对电网背景谐波电压的抗干扰性能,提出一种无谐波检测的三相并网逆变器谐波灵活控制方法,该方法将本地谐波补偿和抗电网背景谐波电压扰动在三相并网逆变器控制中予以统一考虑。所提控制方法可根据控制目标的不同,在谐波抑制和谐波补偿两种模式下灵活切换。谐波补偿模式,在不需要进行谐波电流检测的前提下,可实现对本地负载谐波电流的有效补偿,简化了谐波补偿时并网逆变器的控制操作;谐波抑制模式,可抑制电网背景谐波电压对逆变器输出电流的负面影响,从而提高并网逆变器的抗干扰能力。通过对同步旋转坐标系下控制器到静止坐标系的等效变换,建立了整个控制系统在静止坐标系的频域模型,分析了系统的频域跟踪特性和稳定性。仿真与实验结果证明了所提方法的有效性。

A Flexible Harmonic Control Method for Three-Phase Grid-Connected Inverter without Harmonic Detection

In order to simplify the harmonic compensation control and improve anti-interference ability to grid background harmonic voltage, a flexible harmonics control method for three-phase grid-connected inverter without harmonic detection is proposed. Herein, the local harmonic current compensation and the resistivity against grid background harmonic voltage disturbances are considered together in the controller. The proposed control method can switch between harmonic suppression mode and harmonic compensation mode depending on control targets. In the harmonic compensation mode, this method can achieve effective compensation for local load harmonic current without harmonic current detection. It will simplify the control operation of grid-connected inverter in case of harmonic compensation. In the harmonic suppression mode, this method can suppress the negative impacts of grid background harmonic voltage on the output current of the inverter, so as to improve anti-jamming capability of the inverter. By the equivalent transformation of controller from synchronous rotating reference frame to stationary reference frame, the frequency-domain model of the entire control system in stationary reference system has been established. The frequency-domain tracking characteristics and system stability have been analyzed. The simulation and experimental results have demonstrated the effectiveness of the proposed method.