Compound control method for parallel hybrid active power filters

Abstract

The invention discloses a compound control method for parallel hybrid active power filters, comprising the following steps: (1) acquiring state information of a power grid and a parallel hybrid active power filter; (2) extracting a voltage instruction from the current of the power grid; (3) calculating a voltage error signal; (4) carrying out repetitive control and PI adjustment on a voltage difference signal to obtain a modulation signal; and (5) constructing a PWM signal, wherein the parallel hybrid active power filter includes a passive part and an active part. Through the scheme, the invention can provide a compound control method for parallel hybrid active power filters. In order to overcome the defects of the existing parallel hybrid active power filter controller, a compound control method is provided. A double-loop compound control algorithm, including PI adjustment at the inner loop and repetitive control at the outer loop, is adopted. Odd harmonic, even harmonic and fundamental negative-sequence harmonic can be compensated at high precision. Moreover, the complexity of the system is greatly reduced, the cost is reduced, and the method can be easily used in engineering practice.

Description

technical field [0001] The invention relates to a composite control method, in particular to a composite control method of a parallel hybrid active power filter. Background technique [0002] The parallel hybrid active power filter consists of two parts, PF (passive part) and APF (active part), such as figure 1 Shown: [0003] By detecting the load or the harmonic components in the grid, the active power filter APF is controlled as a controlled current source I APF or voltage source U APF , a single-phase equivalent circuit such as figure 2 Shown: [0004] Among them, the strategy of using the APF to control the controlled current source makes the APF (active part) bear the fundamental voltage, resulting in a large active capacity, and it is difficult to reflect the cost advantage. Therefore, at present, the APF is mostly used to control the controlled voltage source. Strategy, and adopt the voltage control of grid side current, the principle is as follows: [0005] A...

AI Technical Summary

Problems solved by technology

[0007] Conventional PI controllers can only achieve static error-free tracking when the reference signal is DC

In the hybrid active power filter, its reference and feedback voltages are formed by the superposition of multiple harmonics, and the PI regulator cannot accurately track

In addition, because the switching frequency of the device is limited, in order to ensure the attenuation of the switching frequency ripple, the bandwidth of the PI regulator cannot be too large.

Therefore, conventional PI controllers are greatly limited in the application of hybrid active filters,

[0008] Proportional sine integral control and integral control in multi-rotating coordinate systems are based on the idea of ​​selective harmonic compensation, so it is necessary to embed a controller for compensation at each harmonic frequency. In practical applications, the program implementation is cumbersome, and Unable to achieve harmonic compensation within the full bandwidth

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