Nonlinear control method of inverter and equipment thereof

Abstract

The invention provides a nonlinear control method of an inverter and equipment thereof. The nonlinear control method comprises the steps of: acquiring a deviation of an output voltage, wherein the deviation of the output voltage is a difference between a given voltage reference value and an output voltage of an inverter; when the deviation of the output voltage increases in a positive direction, continuously reducing an inner-right feedback coefficient of an inverter inductor current to a first preset value; and the deviation of the output voltage increases in a negative direction, continuously increasing the inner-right feedback coefficient of the inverter inductor current to a second preset value. When a load reduces suddenly, the output voltage of the inverter increases; the deviation of the output voltage increases in the negative direction; the inertia of the current inner ring increases; the gain reduces; and action of the current inner ring slows, thereby performing a function of weakening voltage increase. When the output voltage reduces, the deviation of the output voltage increases in the positive direction; the inertia of the current inner ring reduces; the gain increases; and action of the current inner ring quickens, thereby performing a function of reducing voltage reduction. The nonlinear control method of the inverter further has functions of: improving adaptability of the inverter to the load, enlarging damping to oscillation, and improving system stability.

Description

technical field [0001] The invention relates to the technical field of inverter closed-loop control, in particular to a nonlinear control method and equipment for an inverter. Background technique [0002] In order to enhance the ability of the inverter to adapt to sudden changes in load, the existing voltage source inverter generally adopts a double closed-loop control method of the current inner loop and the voltage outer loop. [0003] The function of the current inner loop is to reduce the inertia of the system through feedback to improve system performance. The current inner loop is divided into two types: the inductive current inner loop and the capacitive current inner loop. Among them, the use of the inductor current inner loop control is convenient for current limiting protection, because many electrical devices in the inverter system can withstand the maximum voltage and current is limited, through the inductor current inner loop control can effectively avoid the o...

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Problems solved by technology

Inverters with dual-mode operation generally adopt load current feed-forward control or capacitor current feedback control in order to have good load adaptability when operating in independent inverter mode, but these methods undoubtedly increase the consumption of hardware resources. It also reduces the reliability of the system

[0005] If the dual closed-loop controllers in the independent inverter mode of the inverter are all fixed parameter PI controllers, then the parameters of the PI controller should be designed according to the no-load operation of the inverter when designing the PI controller. The inverter is equivalent to an underdamped second-order system, and the voltage overshoot is large, so the gain of the voltage PI controller cannot be too large, otherwise the stability of the inverter will be reduced

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