Method for realizing a feedback linearization double hysteresis composite controller of active power filter

Abstract

The invention discloses a method for realizing a feedback linearization double hysteresis composite controller of an active power filter, and the method comprises the following steps of: building a mathematical model which is connected with an active power filter system in parallel in a rotating coordinate system, calculating a reference value of a compensating current, decoupling the model into a pseudo-linear system, taking controlled variables of a main circuit switch function as input variables of the model, determining a reference voltage vector and an error current vector at the alternating current side of a main circuit as well as space regions at which the two vectors are located by virtue of the main circuit switch function, selecting a double hysteresis pulse width modulation method for an output voltage space vector to control the change rate of the error current vector, and adopting a DSP (digital signal processer) chip to realize the feedback linearization double hysteresis composite controller of the active power filter. By adopting the method disclosed by the invention, the problem of parameter coupling in a compensating current component in a system model is solved, thus a system can still rapidly respond under the condition that load parameters are disturbed or suddenly changed; meanwhile, the switching frequency of a main circuit inverter can be effectively reduced, and the switching loss can be reduced.

Description

technical field [0001] The invention relates to a feedback linearization double hysteresis loop composite control method of an active power filter, in particular to a feedback linearization double hysteresis loop composite controller of an active power filter and its realization. Background technique [0002] With the increasingly widespread application of power electronic devices, the grid load is also becoming more and more complex. The nonlinear, impulsive and unbalanced power consumption characteristics of electric loads make the harmonic pollution in the power grid more and more serious, and also bring additional reactive power burden to the power grid. The voltage provided by the ideal public grid should be the power frequency fundamental wave voltage. The emergence of harmonic voltage and harmonic current is a kind of pollution to the public grid, which deteriorates the environment in which the electrical equipment is used, and also brings harm to the surrounding com...

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Problems solved by technology

Hysteresis tracking control has high precision and fast response, but the switching frequency is unstable, which is easy to cause pulse current and switching noise; triangular wave comparison control has constant switching frequency, high device safety, but slow response and low precision

In addition, the deadbeat control strategy has the advantages of strict mathematical derivation, no overshoot in tracking, and good dynamic performance, but the control effect is not good under load disturbance and nonlinear load.

As a nonlinear control method, one-cycle control has the duality of modulation and control, but requires a fast reset integral circuit, and has poor ability to suppress load disturbances

At the same time, none of the above-mentioned control methods can solve the nonlinear and parameter coupling problems of the mathematical model of the active power filter system.

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