Improved specified sub-harmonic current compensation control method for active power filter

Abstract

The present invention relates to an improved specified sub-harmonic current compensation control method for an active power filter. Based on the harmonic current control of a conventional shunt activepower filter with extracted each sub-harmonic current as a harmonic current command, the PI closed-loop control on each sub-harmonic current is carried out. At the same time, after a fundamental wavecurrent command value and a harmonic wave current command value are superimposed, a switch signal of a power switch tube is obtained through a deadbeat controller, the tracking of harmonic command current is achieved, thus the high accuracy compensation of specified sub-harmonic current can be ensured, and the dynamic performance of the system can be ensured.

Description

technical field [0001] The invention relates to the technical field of harmonic current compensation control of an active power filter, in particular to an improved active power filter harmonic current compensation control method of a specified order. Background technique [0002] At present, non-linear devices such as uncontrollable rectifying loads are widely used in industrial and civil applications, and the resulting grid pollution problem is becoming more and more significant. Active Power Filter (APF) is one of the effective methods to suppress harmonics. [0003] The compensation performance of the APF is determined by the harmonic current extraction algorithm and the harmonic current compensation control method. However, limited by the delay caused by factors such as sampling and digital control, there is more or less a certain degree of phase difference between the sampled value and the actual value of the harmonic current of different frequencies. For example, in...

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Problems solved by technology

For example, in the prior art, a specified harmonic extraction algorithm based on a multi-synchronous rotating coordinate system is used to solve the problem of delay in the extraction of each harmonic current, but this algorithm only extracts the harmonic current directly as The harmonic current command is not closed-loop controlled, and the compensation accuracy is lacking; another example: the harmonic current and the compensation current are both rotated and coordinately transformed and the harmonic current PI regulator is designed, but this algorithm is developed based on FPGA , the program design is complex and difficult to implement; as another example: the PI closed-loop adjustment of each harmonic current based on the multi-synchronous rotating coordinate system is used to ensure the compensation accuracy of the harmonic current, and the current adjustment adopts decoupling control; another example is proposed: A dead-beat control method has been developed. This control method has the advantages of no overshoot and quick response, and is very suitable for transient control. However, because this control method has no integral function, it cannot eliminate the static error. To sum up, it is currently in The following problems need to be improved in the harmonic current steady-state control accuracy: poor dynamic performance of the system, low steady-state accuracy, etc.

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