Grid-voltage-sensor-free vector control method of synchronous PWM (Pulse Width Modulation) rectifier

Abstract

The invention discloses a grid-voltage-sensor-free vector control method of a synchronous PWM (Pulse Width Modulation) rectifier. The method comprises the following steps: estimating an initial phase angle of grid voltage before a PWM rectifier starts; adopting synchronous coordinate transformation to obtain active current and reactive current under a grid synchronous coordinated system; giving active current through the deviation PI (Proportional Integral) regulation of direct current busbar voltage, and giving reactive current through giving reactive power; adopting active current deviationPI and reactive current deviation PI to obtain a phase angle of grid voltage and output voltage of the rectifier; and controlling switch components through the output voltage of the rectifier. According to the invention, the vector control method has good performance for a three-phase symmetrical / asymmetric grid without a neutral point. The rectifier can work stably under the unit power factor byestimating the initial phase angle of the grid voltage, and the reactive power can be adjusted freely, thus the same control performance when a grid voltage sensor is used is achieved.

Description

technical field [0001] The invention relates to a vector control technology of a synchronous PWM rectifier without a grid voltage sensor, in particular to a vector control method of a synchronous PWM rectifier without a grid voltage sensor. Background technique [0002] With the extensive application of power electronic devices, especially rectification equipment, the rectification equipment will inject a large amount of harmonic and reactive current into the grid, causing serious pollution to the grid. At the same time, regenerative energy cannot be fed back to the grid, resulting in a significant waste of resources. The PWM rectifier has the characteristics of good sinusoidal input current and bidirectional flow of energy, and has been widely used in wind power generation and reactive power compensation and other fields. At present, the voltage-type PWM rectifier is widely used, and the voltage-oriented vector control method is mainly used. At this time, it is necessary to...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a synchronous PWM rectifier vector control method without a grid voltage sensor, which not only solves the problems of high cost and complexity caused by the need for numerous sensors and signal processing circuits in the PWM rectifier in the prior art, but also Also solved the problem of PWM rectifier not starting due to inaccurate initial angle observation

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