Multi-channel power grid voltage synchronous signal extraction device and method

Abstract

The invention provides a multi-channel power grid voltage synchronous signal extraction device. The device comprises an [alpha]-[beta] stationary coordinate system transformation circuit T[alpha][beta], positive and negative sequence d-q synchronous rotating coordinate system transformation circuit e<j[omega]t>, e<-j[omega]t>, e<j5[omega]t> and e<-j7[omega]t> of different frequencies, a subtracter, a PI adjuster, an integrator and a proportion arithmetic unit. The multi-channel power grid voltage synchronous signal extraction device has the advantages that under the condition that an input voltage has different-frequency harmonic waves, the device is capable of extracting synchronous signals of fundamental waves and can also extracting different-frequency positive and negative sequence components under the [alpha]-[beta] coordinate system and the d-q coordinate system, and frequency adaptivity is realized; in addition, negative sequence decoupling or instant symmetric component separation is not needed, only a d-q synchronous rotating coordinate system transformation circuit Tdq and feedback are needed, the separation and extraction of fundamental wave positive and negative sequence components are realized under a single synchronous reference coordinate system, the structure is simpler, and the operation amount is smaller.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a multi-channel grid voltage synchronous signal extraction device and method. Background technique [0002] A converter is an electrical device that changes the voltage, frequency, number of phases, and other power or characteristics of the power system. There are many types of converters, which are widely used in various working machines. Among them, for three-phase grid-connected converters The most important step in inverter control is to extract the synchronous signal of the grid voltage, that is, the amplitude, phase and frequency of the fundamental wave and each harmonic voltage. Since grid voltage asymmetry is a common phenomenon, it has a great impact on the operation of the three-phase grid-connected converter; therefore, in order to meet the needs of the asymmetric control strategy of the three-phase grid-connected converter, the synchronous signal The extraction also ...

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Problems solved by technology

This structure can effectively filter the influence of grid voltage asymmetry on synchronous signal extraction, but the operation of instantaneous symmetric components increases the computational complexity of the system and the complexity of the system structure

[0009] Therefore, the existing power grid voltage synchronization signal extraction devices are mainly aimed at the fundamental wave signal extraction of the power grid, and cannot provide multi-frequency positive and negative sequence signals, nor can they quickly and accurately extract synchronization signals under the condition of grid voltage asymmetry. Due to the requirements of frequency adaptability and simplicity of implementation, a new grid voltage synchronization signal extraction technology is urgently needed to overcome the above defects

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