Control method of SVG dynamic reactive power compensation and harmonic management based on PI feedforward decoupling

Abstract

The invention discloses a control method of SVG dynamic reactive power compensation and harmonic management based on PI feedforward decoupling. The method comprises a step of inputting a difference value between DC side reference voltage and capacitor voltage to a DC side PI controller, a step of sampling three-phase load current through a current transformer, carrying out adc/dq conversion on signals and sending the signals to a low-pass filter LPF, adjusting dq axis components outputted by the LPF to be reference command current of a PI feedforward decoupling controller, comparing the reference command current and grid current under a dq coordinate system, and sending an error signal to the PI feedforward decoupling controller, a step of carrying out dq/abc conversion on an output signalof the PI feedforward decoupling controller, inputting the signal into an SVPWM driving module to generate a switching signal to control a three-phase full-bridge inverter, and allowing the three-phase full-bridge inverter to generate a compensation signals to realize the dynamic reactive compensation and harmonic management. According to the control method, a complex controller is not needed, aharmonic compensation effect can be achieved by using the PI controller, the control method is simple and easy to implement, and the compensation effect is better than that of a conventional control method.

Description

technical field [0001] The invention belongs to the field of power electronics, and in particular relates to a control method for SVG dynamic reactive power compensation and harmonic control based on PI feedforward decoupling. Background technique [0002] With the wide application of non-linear and asymmetrical loads, the problem of reactive power and harmonic pollution in the power system is becoming more and more serious. The traditional reactive power compensation and harmonic suppression methods have been difficult to meet the needs of modern power systems. Static var generator (SVG) has attracted extensive attention as a new reactive power compensation and harmonic control device. [0003] Traditional SVG research focuses on the detection and control of load reactive and harmonic currents, and many reactive and harmonic current detection algorithms and control methods have been proposed. However, the advantages and disadvantages of reactive power and harmonic current ...

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Problems solved by technology

However, the advantages and disadvantages of reactive power and harmonic current detection methods will significantly affect the compensation effect of active power filters, and it is also a major difficulty to realize the control of load reactive power and harmonic current.

For example, although the hysteresis control is simple to implement and has good dynamic response, the unfixed switching frequency is a serious shortcoming. Of course, some scholars have proposed a hysteresis control method with a fixed frequency, but most of them have the practical problem that it is difficult to control the load; another example Cascade proportional resonance control, since the nonlinear asymmetrical loads are mostly rectifier loads, the harmonic current order is mainly 6k±1 times, so a large number of resonant controllers are cascaded to achieve reactive power and harmonic compensation, but the control accuracy The higher the number of cascaded resonant controllers, the more cascaded resonant controllers. The more cascaded resonant controllers, the higher the requirements for the digital processor, and the more difficult it is to realize. In addition, there are other orders of harmonic currents in practical applications. Therefore, cascaded proportional resonant controllers are also difficult to achieve reactive power and harmonic current compensation well, and most other similar control methods also have such problems

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