Sliding-mode variable structure control method of single phase grid-connected inverter based on multi-resonant sliding mode surface

Abstract

The invention discloses a sliding-mode variable structure control method of a single phase grid-connected inverter based on a multi-resonant sliding mode surface. The method comprises the steps of: firstly, building a linear sliding mode surface according to detected current i1 of an inverter side filter inductor of the single phase grid-connected inverter, the voltage vc of a filter capacitor, the current i2 of a network side filter inductor, and the target output current i1* of a grid-connected inverter system, the target voltage vC* of the filter capacitor and the grid-connected target current i2*; adding a resonant item into the linear sliding mode surface so as to obtain the multi-resonant sliding mode surface; designing a sliding-mode variable structure controller by the multi-resonant sliding mode surface, leading a linear state feedback controller to an original nonlinear controller to obtain a final control quantity modulation wave d(s), and finally comparing the modulation wave with a carrier wave to generate a driving signal for driving a switch tube to act. According to the control method disclosed by the invention, the robustness and dynamic response ability of the grid-connected inverter system are improved; the tracking accuracy of grid-connected current is also improved; the harmonic content is removed, and the control method is simple and easy to achieve.

Description

technical field [0001] The invention belongs to the application field of new energy power generation system control technology, and in particular relates to a sliding mode variable structure control method based on a multi-resonant sliding mode surface for a single-phase grid-connected inverter. Background technique [0002] With the development of new energy sources, grid-connected inverters have been extensively studied. Among them, the stability control of grid-connected inverter is a research hotspot nowadays. Its control objectives: fast tracking capability, strong robustness to external disturbance, zero steady-state error and low total harmonic distortion. [0003] For the control problem of grid-connected inverter, the existing control methods can be divided into two categories: linear control and nonlinear control. The former includes PI control, PR control, deadbeat control, and repetitive control, etc.; the latter includes hysteresis control, Bang-Bang control, ...

AI Technical Summary

Problems solved by technology

[0006] 1. In the actual sliding mode control system, due to the influence of non-ideal switches and other factors, the sliding mode produces high-frequency chattering, which is the unique "chattering" phenomenon in the sliding mode variable structure control system

[0007] 2. In the actual system, the system modeling cannot be completely accurate, and there will be many defects in the system model, such as: inaccurate power component parameters, unknown external disturbances, etc.

Although the sliding mode variable structure control can maintain the stability and robustness of the system well, it cannot effectively guarantee the control accuracy of the system.

Integral sliding mode control can effectively reduce the DC steady-state error, but the ability to suppress the AC steady-state error and total harmonic distortion is very limited, and needs to be further improved

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