Voltage-type PWM (pulse width modulation) rectifier power compensation control method under asymmetrical power grid faults

Abstract

The invention discloses a voltage-type PWM (pulse width modulation) rectifier power compensation control method under asymmetrical power grid faults. The technical scheme mainly includes that the voltage-type PWM rectifier power compensation control method under the asymmetrical power grid faults includes: enabling input reactive power and input active power which are obtained by computation to pass through band-pass filters and controllers so that second harmonic compensation voltages are obtained, compensating the second harmonic compensation voltages into output voltage subjected to traditional vector control, and finally, obtaining reference voltages under a two-phase static coordinate system. After voltage signals are subjected to space vector pulse width modulation, switching signals for controlling power devices are generated, and stable control of reactive power and active power is achieved. Under the condition of the asymmetrical power grid faults, computation and decomposition of a positive sequence component and a negative sequence component in a system are not needed, power pulses of the voltage-type PWM rectifier can be compensated directly, stable control of reactive power and active power is achieved, operating capability of the voltage-type PWM rectifier under the condition of the asymmetrical power grid faults can be improved effectively, and the method is simple in algorithm and easy to implement.

Description

[0001] technical field [0002] The invention relates to a control method of a voltage-type PWM rectifier, which belongs to the control field of power electronic power conversion devices, and in particular to a power compensation control method of a voltage-type PWM rectifier under an asymmetric fault of a power grid. Background technique [0003] When an asymmetrical fault occurs in the power grid, the grid voltage will drop asymmetrically, and the DC side of the PWM rectifier using the vector control strategy will have second harmonic power, resulting in fluctuations in the DC bus voltage and a large number of harmonics at the input side of the grid, seriously affecting the PWM output quality of the rectifier. [0004] When the grid is asymmetrically faulted, the grid voltage will drop asymmetrically. At this time, the more classic PWM rectifier control method is to use the symmetrical component theory to decompose the positive and negative sequence of the system, and re...

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Problems solved by technology

This method requires positive and negative sequence decomposition operations in the current inner loop, which will increase the complexity of the controller and reduce the dynamic response of the system

In order to avoid positive and negative sequence decomposition calculations in the current loop and improve system response speed, some scholars use a resonant controller to uniformly adjust the positive and negative sequence currents. Although this method avoids the positive and negative sequence calculations in the current inner loop , but in order to calculate the given value of positive and negative sequence current, it is necessary to decompose the positive and negative sequence of each component in the system, which increases the calculation amount of the control scheme

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