A control method and system of a three-phase lcl type grid-connected inverter

Abstract

The invention discloses a control method and system for a three-phase LCL type grid-connected inverter, which includes obtaining grid current i G‑a,b,c and grid voltage u G‑a,b,c ; get i G‑a,b,c * and i in the two-phase stationary coordinate system Gα i Gβ , u Gα , u Gβ i Gα * i Gβ * ; the first ADRC according to i Gα , u Gα i Gα * Get the actual control quantity u α , the first virtual control quantity u' of the first state feedback control rate output in the first ADRC α with i Gα There is a pure series integral relationship between them; the second ADRC is based on i Gβ , u Gβ i Gβ * Get the actual control quantity u β , the second virtual control quantity u' of the second state feedback control rate output in the second ADRC β with i Gβ There is a pure series integral relationship between them; the SVPWM controller is based on u α and u β Generate pulse width modulation PWM signal and output to grid-connected inverter. The control algorithm of the invention is simple, and the parameters can be set by engineering, and the cost is low.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverters, in particular to a control method and system for a three-phase LCL type grid-connected inverter. Background technique [0002] New energy power generation is the main way to solve the contradiction between human's ever-increasing energy demand and less and less traditional fossil energy. The grid-connected utilization of new energy power generation is the main way for large-scale promotion and utilization of new energy power generation. The grid-connected inverter is the interface between the electric energy generated by the new energy source and the grid. In order to suppress harmonics generated by PWM (Pulse Width Modulation, pulse width modulation) chopping of the grid-connected inverter, a filter needs to be added between the inverter and the common point of the grid. Among them, commonly used filters include L-type filters and LCL-type filters, but since the high-frequency ...

AI Technical Summary

Problems solved by technology

The existing state observer-based methods are only used to observe the required current and voltage state variables, and then use the observed state variables as inner loop feedback variables for control, still need to combine PID controllers, PR controllers, and repetitive controllers It is also difficult to control parameters, and it is impossible to simplify the complexity of the control algorithm while reducing the number of sensors.

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