Common-mode voltage suppression method for wind power dual-winding generator system

Abstract

The invention relates to a common-mode voltage suppression method for a wind power generation double-winding generator system. Each set of windings of a double-winding wind power generator is connected to a machine-side converter, and the frequency-changing AC power is converted into DC power, and then passed through the grid-side converter. The DC power is converted into AC power with a fixed frequency by a transformer, and finally it is boosted and transmitted to the power grid through a transformer. The double-winding wind turbine has two sets of windings, and the four converters use voltage pulse width modulation PWM signals to control the converters. , through two machine-side converters to control the phase inversion of the carrier phase used to generate the PWM signal; two grid-side converters to control the phase inversion of the carrier phase used to generate the PWM signal to reduce the common mode voltage of the system. This method can reduce the common-mode voltage of the system, prolong the insulation life of the motor windings, and reduce the harm of electromagnetic interference in the system without changing the structure of the motor and any other hardware for the large-scale motors and converters that have been manufactured. EMC standard requirements.

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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