Three-ring control method of three-phase PWM (Pulse-Width Modulation) rectifier for LCL (Lower Control Limit) filtering

The invention relates to a three-ring control method of a three-phase PWM (Pulse-Width Modulation) rectifier for LCL (Lower Control Limit) filtering and belongs to the field of rectifier control. The three-ring control method is characterized in that an output voltage of a rectifier, a grid-side inductive current, an inductive current at the side of a rectifier bridge are respectively sampled by using a group of voltage detection transmitters and two groups of current detection transmitters so as to control an output direct-current voltage and a grid-side power factor of the three-phase PWM rectifier. The control method provided by the invention has the outstanding advantages that the output direct-current voltage of the three-phase PWM rectifier is controlled with high precision and good stability; the grid-side power factor is high; the capability of resisting voltage distortion interference of a power grid is strong; and a bridge arm switching tube is convenient to protect, the control method has high reliability and the like. Therefore, the control method provided by the invention is very suitable for controlling the three-phase PWM rectifier for the LCL filtering.