Positive and negative sequence impedance measuring module, system and method for new energy grid-connected converter

Abstract

The invention provides a positive and negative sequence impedance measuring module, a positive and negative sequence impedance measuring system and a positive and negative sequence impedance measuringmethod for a new energy grid-connected converter. The positive and negative sequence impedance measuring module comprises a disturbance voltage injection unit, a grid-connected point voltage / currentacquisition unit, an impedance calculation unit and an impedance bode map generating unit. The positive and negative sequence impedance measuring system comprises a controller, I / O interface equipmentand a real-time simulation system which are sequentially connected, wherein the real-time simulation system comprises the positive and negative sequence impedance measuring module. Compared with theprior art, the positive and negative sequence impedance measuring module, the positive and negative sequence impedance measuring system and the positive and negative sequence impedance measuring method for the new energy grid-connected converter are provided by the invention, the positive and negative sequence impedance measuring module can control and disturb phases, amplitude values and waveforms of a voltage signal flexibly; the controller, the I / O interface equipment and the real-time simulation system in the positive and negative sequence impedance measuring system form a hardware-in-loopcontrol real-time simulation system, real-time simulation and positive and negative sequence impedance measurement can be carried out on the new energy grid-connected converter, and the precision ofimpedance measurement of the new energy grid-connected converter is improved.

Description

technical field [0001] The invention relates to the technical field of wind power generation, in particular to a positive and negative sequence impedance measurement module, system and method of a new energy grid-connected converter. Background technique [0002] Wind turbines, photovoltaic power generation units and energy storage devices are connected to the grid through grid-connected converters, so as to realize grid-connected operation of new energy power generation. However, the interaction between the grid-connected converter and the grid and its own interaction will affect the stability of the grid-connected new energy power generation system. Therefore, the stability of new energy grid-connected converters must be considered in the design and operation of large-scale new energy power plants, and the stability of new energy grid-connected converters is closely related to the impedance of the converter in the wide frequency range . Among them, the harmonic voltage i...

AI Technical Summary

Problems solved by technology

Conventional impedance measurement devices can only measure the impedance of new energy grid-connected converters with a capacity of tens of kilowatts, and the measurement time is long and the measurement accuracy is not enough

The off-line simulation measurement device can measure the impedance of megawatt-level new energy grid-connected converters, but the measurement results are greatly affected by the simulation model, and the measurement results are inaccurate

Especially in the impedance measurement of the three-phase AC converter, the positive-sequence impedance of the converter needs to be measured, and neither the conventional impedance measurement device nor the off-line simulation measurement device can inject a three-phase AC fan converter modulated by multiple signals. The complex signals together, so the positive and negative sequence impedance of the new energy grid-connected converter cannot be accurately measured

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