Inverter output voltage state stabilizing method based on sliding mode control

Abstract

The invention discloses an inverter output voltage state stabilizing method based on sliding mode control. The method comprises the following steps: step 1, a reference voltage vref is set, an operation model is established according to an inverter circuit, and the difference between an output voltage V and the reference voltage vref is defined as the error signal value s of a sliding mode variable; step 2, a dynamic parameter value Beta is set, wherein s<=Beta sM, s>=Beta sm, and a controller structure is composed of four states S<M><+>, S<m><+>, S<M><-> and S<m><-> and an initial state; step 3, the error signal value s and the derivative thereof S(.) are converged to a sliding mode surface s=0 and S(.)=0 through a control algorithm according to real-time update of the dynamic parameter value; and step 4, the output voltage V=vref+s is output.

Description

technical field [0001] The invention relates to the field of automatic control, in particular to a method for steady-state output voltage of an inverter based on sliding mode control. Background technique [0002] Inverters are usually used to invert DC power into AC power to power AC loads. At present, the most widely used are UPS power supply and photovoltaic power generation system. As the connection point between the photovoltaic power generation system and the public grid, the photovoltaic inverter's output voltage and output current can track the external reference sinusoidal signal through the control method. The research on this control method has become the research focus at home and abroad. [0003] At present, the control output methods of the inverter include natural switching method, high-frequency pulse width modulation (PWM) and sliding mode control. The natural switching method has good dynamic performance because it requires only one switch control to achi...

AI Technical Summary

Problems solved by technology

The sliding mode control technology has been proposed as a PWM control strategy in the Dc-Dc switching controller. The sliding mode control technology has strong robustness to the system uncertainty and the change of the load, so that the output signal can track the upper Reference signal, but the sliding mode control scheme also has shortcomings in the design process, such as the transition process established under the sliding mode condition and the trade-off analysis between the sliding mode is difficult, and because the inductor voltage and capacitor current output by the inverter Usually is not easy to measure, so it increases the complexity of the controller design

Images