Method of controlling three-phase PWM inverter based on second-order sliding mode and disturbance observer

Abstract

The invention discloses a method of controlling a three-phase PWM (Pulse Width Modulation) inverter based on a second-order sliding mode and a disturbance observer. The method is applicable to the high-performance control of the three-phase AC (alternating current) inverter and comprises the steps: firstly, decoupling a three-phase AC inverter system into two single-phase second-order sub-systems in the use of 3 / 2 coordinate transformation; secondly, designing the two second-order sub-systems on this basis and designing the disturbance observer to observe matched and non-matched disturbances under the condition of considering the load transformation of the system; and thirdly, designing the compound control method of the second-order sliding mode and the disturbance controller on the basis of acquiring disturbance estimation values so as to improve the anti-load-disturbance ability of the system. The method is simple to realize and has less regulation of parameters; the voltage output harmonic waves of the three-phase AC inverter system can be reduced effectively, so that the purpose of improving stability precision of the AC inverter system is achieved and the application of the high-performance AC inverter system in the voltage output field is satisfied.

Description

technical field [0001] The invention relates to a three-phase power electronic inverter control technology, in particular to a three-phase PWM inverter control method based on second-order sliding mode control and a disturbance observer. Background technique [0002] With the increasingly prominent environmental problems and the gradual depletion of fossil energy, new energy power generation has received more and more attention. As the main interface device, the inverter brings the most important power quality problem is harmonic pollution. Low-performance inverters will threaten the safety of load equipment and affect the use of electric energy on the user side. Controlling the inverter to reduce harmonic pollution through advanced control algorithms plays an important role in improving power quality and maintaining grid stability. [0003] To this end, a variety of control methods have been proposed: PID control, linear feedback control, repetitive control, resonance con...

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Problems solved by technology

[0006] However, the inherent discontinuous switching characteristics of the sliding mode variable structure control will cause chattering problems in the system

Traditional sliding mode control often requires a large switching gain to eliminate external disturbances and uncertainties. Therefore, external disturbances and uncertainties are the main sources of chattering in sliding mode control, especially when faced with unmatched disturbances. Sliding mode appears powerless

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