Wind power generation double winding generator system common-mode voltage suppression method

Abstract

The invention relates to a wind power generation double winding generator system common-mode voltage suppression method. Each set of winding of a double winding wind power generator is connected witha generator side converter to convert variable-frequency AC electric energy into DC electric energy, then the DC electric energy is converted into the fixed-frequency AC electric energy through a network side converter and finally the fixed-frequency AC electric energy is boosted through the transformer and transmitted to the power grid. The double winding wind power generator is provided with twosets of windings. Four converters are controlled by the voltage pulse width modulation PWM signals. The common-mode voltage of the system is reduced by the method that the two generator side converters control reversal of the carrier phase selected for generating the PWM signals and the two network side converters control reversal of the carrier phase selected for generating the PWM signals. According to the method, the motor structure or any other hardware of the manufactured large motor and converters does not need to be changed, and the common-mode voltage of the system can be reduced, theinsulation service life of the motor windings can be prolonged, the harm of the electromagnetic interference of the system can be reduced and the requirements of the electromagnetic compatible standard can be met.

Description

technical field [0001] The invention relates to a motor control technology, in particular to a common-mode voltage suppression method for a wind power generation double-winding generator system. Background technique [0002] With the development of wind power generation technology, the power of a single wind turbine is getting bigger and bigger, and the current requirement is increasing proportionally at the same voltage level. By designing a generator with double windings, the average current distribution can be kept within the allowable capacity under the condition of power increase. [0003] A typical dual-winding wind turbine control system such as figure 1 As shown in Fig. 1, each set of windings is connected with two converters with similar hardware structure and different software functions, which are called generator-side converter and grid-side converter respectively. First, the wind turbine captures wind energy through the blades and converts it into rotating mec...

AI Technical Summary

Problems solved by technology

[0005] For megawatt-scale wind turbine and converter systems, the common mode voltage of the system is high due to the use of voltage pulse width modulation (PWM), causing excessive shaft current, which is likely to cause electrical corrosion damage to the bearings; Cause damage to the motor winding insulation, affecting the life and failure rate of the motor winding insulation

Excessive common-mode voltage may also cause electrical system electromagnetic interference (EMI) and electromagnetic compatibility (EMC) problems; if there is a large amount of zero-sequence current flowing, it will also cause unnecessary system zero-sequence current loss

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