Current optimization control system and method of grid-connected photovoltaic inverter

Abstract

The invention discloses a current optimization control system and method of a grid-connected photovoltaic inverter. The system comprises a data acquisition module, a signal converter, a weighted average current controller, a cross coupling compensation controller, a dead beat controller and a PWM (pulse-width modulation) generator, wherein an output end of the data sampling module is connected with the signal converter, and an output end of the signal converter is connected with the weighted average current controller and the cross coupling compensation controller; outputs of the weighted average current controller and the cross coupling compensation controller are connected with an adder; an output end of the adder, the dead beat controller and the PWM generator are sequentially connected. Compared with conventional single-loop control systems, the system has the advantages that a dead beat current control system with feed-forward compensation feedback is designed, and introduced static errors of weighed current control models can be eliminated, so that output current is more accurate to control; besides, the tracking speed is higher and the control effect is better.

Description

technical field [0001] The invention belongs to the field of photovoltaic grid-connected power generation, and in particular relates to a current optimization control system and method of a grid-connected photovoltaic inverter. Background technique [0002] The core component of the photovoltaic solar grid-connected power generation system is a grid-connected inverter composed of power electronic switching devices. In order to eliminate the huge amount of harmonics brought by the switching devices, the inverter will be equipped with an LCL filter with a large-capacity high-frequency absorption capacitor. device. Although the introduction of capacitors reduces the voltage output ripple and makes the output of the inverter smoother, it also introduces some control problems, especially when connecting to the grid, it enhances the resonance of the LCL filter and reduces the current Tracking control accuracy, resulting in static tracking error, in severe cases, the inverter will...

AI Technical Summary

Problems solved by technology

Although the introduction of capacitors reduces the voltage output ripple and makes the output of the inverter smoother, it also introduces some control problems, especially when connecting to the grid, it enhances the resonance of the LCL filter and reduces the current Tracking control accuracy, resulting in static tracking error, in severe cases, the inverter will be out of control, and the system will go off-grid.

Images