Capacitor voltage single sensor-based LCL-type gird-connected inverter control method

Abstract

The invention provides a capacitor voltage single sensor-based LCL-type gird-connected inverter control method, relates to an inverter control method, and aims at solving the problems that an active damping control sensor of an LCL-type gird-connected inverter is high in cost and a traditional observer method is complicated. The control method comprises the following steps: (1) collecting a capacitor voltage uC in an LCL filter; (2) inputting the collected capacitor voltage uC into an extended state observer to obtain a virtual state quantity; (3) converting the obtained virtual state quantity, and obtaining a real state quantity estimation value as shown in the specification and a network voltage estimation value as shown in the specification, wherein the state quantity estimation value comprises a network current estimation value as shown in the specification and an inverter current estimation value as shown in the specification; and (4) generating a drive signal of the inverter according to the obtained network current estimation value as shown in the specification, inverter current estimation value as shown in the specification and network voltage estimation value as shown in the specification, and controlling the inverter by the drive signal. The capacitor voltage single sensor-based LCL-type gird-connected inverter control method is applied to control on the LCL-type gird-connected inverter in the occasions of renewable energy conversion and the like.

Description

technical field [0001] The invention relates to a control method, in particular to a control method of an LCL type grid-connected inverter based on a capacitor voltage single sensor. Background technique [0002] The large-scale utilization of renewable energy represented by photovoltaics and wind power is one of the ways to solve the contradiction between energy, environment and resources, and realize the sustainable development of human beings. The grid-connected inverter plays the role of converting the electric energy generated by the renewable energy into the alternating current acceptable to the grid. In order to suppress the harmonics generated by the PWM chopping of the grid-connected inverter, a filter needs to be added between the inverter and the grid. Common filter types for grid-connected inverters include L-type and LCL-type. The L-type filter is easy to control and has good stability. It is widely used in inverter products. Its disadvantage is that it needs ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of high cost of active damping control sensors for LCL grid-connected inverters and the complexity of traditional observer methods. The present invention provides a control method for LCL grid-connected inverters based on a capacitor voltage single sensor

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