Improved dead-beat control method for pulse width modulation (PWM) rectifier at unbalance of voltage of power grid

Abstract

The invention discloses an improved deadbeat control method of a PWM rectifier when the grid voltage is unbalanced. The key points of the technical solution of the present invention are: an improved dead-beat control method for a PWM rectifier when the grid voltage is unbalanced, the calculated input active power and reactive power are passed through a band-pass filter and a PI controller, and are compensated The voltage calculation obtains active power and reactive power double frequency voltage compensation items respectively, and takes this voltage compensation item as the input of the established voltage reference value calculation model to obtain the reference value of the converter input voltage, and then uses the grid voltage position angle as the transformation The reverse Park transformation is performed on the angle to obtain the input voltage in the two-phase stationary coordinate system. After the voltage signal is modulated by the space vector pulse width, the switching signal for controlling the power device is generated. The invention can perform real-time compensation on the model of the PWM rectifier, can effectively restrain the input active power and reactive power pulsation of the PWM rectifier, and reduce the voltage fluctuation of the DC bus.

Description

technical field [0001] 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, in particular to an improved deadbeat control method of a PWM rectifier when the grid voltage is unbalanced. Background technique [0002] For the operation and control of power converters, scholars in related fields have proposed many advanced control algorithms, such as single-cycle control, predictive current control, adaptive control, sliding mode variable structure control and deadbeat control, etc., based on space voltage vector The PWM current deadbeat control method has constant switching frequency and good regulation performance, and its application in power electronics has shown great advantages. The deadbeat control method is based on the mathematical model of the control object, and calculates the control output in the current control cycle by sampling the feedback variable values, so th...

AI Technical Summary

Problems solved by technology

Under the unbalanced condition of the power grid, the input and output power of the three-phase voltage-type PWM rectifier based on the traditional deadbeat control method will be unstable, the DC bus voltage will fluctuate, and the power electronic equipment will flow a large negative sequence current, which will affect the power. Safe operation of devices and quality control of rectifiers

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