Nonlinear control method of Buck-Boost converter system

Abstract

The invention discloses a nonlinear control method of a Buck-Boost converter system. The nonlinear control method of the Buck-Boost converter system is characterized by comprising the following steps that first, an input voltage, an inductive current, a capacitor voltage and a state average model of a Buck-Boost converter main circuit are obtained; then, the cooperative control law of the Buck-Boost converter system is obtained; afterwards, the expectation value of the inductive current is obtained; at last, the cooperative passive control law of the Buck-Boost converter system is obtained, and therefore nonlinear control over the Buck-Boost converter system is achieved. By means of the nonlinear control method of the Buck-Boost converter system, the transient overshoot of the inductive current of the Buck-Boost converter system can be effectively removed, the steady state error of the capacitor voltage is reduced, and thus the stability of the Buck-Boost converter system is improved.

Description

technical field [0001] The invention relates to a DC-DC converter control system, more specifically to a nonlinear control method of a Buck-Boost converter system with boost and step-down functions. Background technique [0002] The Buck-Boost converter has been widely used in the field of power electronics due to its advantages of simple structure, wide input voltage range and flexible implementation of step-up and step-down control. [0003] The Buck-Boost converter usually adopts the classic double-closed-loop PI control of the current inner loop and the voltage outer loop. Closed-loop PI control often cannot obtain satisfactory system dynamic and static control performance, and even the phenomenon of unstable operation of the system may occur, so it is still necessary to find a high-performance nonlinear control strategy. [0004] For Buck-Boost converters, commonly used nonlinear control strategies include sliding mode control, passive control and cooperative control. ...

AI Technical Summary

Problems solved by technology

In order to improve the performance of the system, on the basis of cooperative control, the selection of macro variables in the cooperative control is improved to reduce but not completely eliminate the transient overshoot of the inductor current at the cost of increasing software overhead. Searching for a Control Method to Effectively Suppress Transient Overshoot of Inductor Current

On the basis of cooperative control, the genetic algorithm is introduced to optimize the parameters of the cooperative controller. Because the macro variable selection includes an integral link, the Buck-Boost converter system can be stabilized to Balance point, but the inductor current of the Buck-Boost converter still has a transient overshoot, and the integration link is introduced in the cooperative control strategy, and the genetic algorithm is used to optimize the controller parameters, which leads to a complex control strategy, increases software overhead, and is not easy to control the algorithm real-time implementation of

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