Method for fixed-time ring-width-variable current control of three-phase three-wire system SAPF (Shunt Active Power Filter)

Abstract

The invention discloses a method for fixed-time ring-width-variable current control of a three-phase three-wire system SAPF (Shunt Active Power Filter). The method comprises the following steps of: decoupling a three-phase current; carrying out single-phase analysis to obtain a calculation formula for ring-width-variable hysteresis control; and discretizing the obtained calculation formula for the ring-width-variable hysteresis control, and introducing a fixed-time control time Ts. The method retains the advantages of high tracking precision and rapid dynamic response of the traditional current hysteresis control method, simultaneously effectively limits the maximal switching frequency and fluctuation range of a switching device, reduces switching loss and mechanical noise, and facilitates the design of a filter circuit at an outlet side of the SAPF; and the invention provides the discretization control method for ring-width-variable current control based on a fixed time principle, and the discretization control method is applicable to an SAPF system taking DSP (Digital Signal Processor) as a core control chip and has a good engineering application prospect.

Description

technical field [0001] The invention relates to a method for timing and variable loop width current control of a three-phase three-wire active power filter (SAPF), which is suitable for the output current control of the SAPF inverter side. Disadvantages of unfixed frequency, a new inverter modulation method designed based on DSP digital control system, belongs to the field of inverter control technology. Background technique [0002] In recent years, the rapid development of power electronics technology and the widespread use of various nonlinear power electronic devices have injected a large amount of harmonic current into the public power system. These harmonic currents will seriously affect the power quality of the grid, causing a series of problems such as device overheating, excessive neutral point current, and low power factor. Compared with the traditional passive power filter, the shunt active power filter (Shunt Active Power Filter, SAPF) has many advantages: excel...

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Problems solved by technology

[0006] Purpose of the invention: In order to solve the problem that the switching frequency is not fixed and the design of the output filter is difficult in the traditional hysteresis control method, the present invention designs a timing variable loop width current control method applied to the active power filter, which can ensure the device's The switching frequency is fixed at the set value, which facilitates the design of the output port filter of the SAPF

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