High-precision anti-interference fixed-point computer three-phase voltage frequency measurement phase-locking algorithm

Abstract

The invention discloses a high-precision anti-interference fixed-point computer three-phase voltage frequency measurement phase-locking algorithm. The algorithm includes the following steps that: virtual discrete sinusoidal signals are constructed; sampling is performed to obtain a three-phase alternating current voltage sampling sequence, and a corresponding reference angle is recorded; the instantaneous D component value and Q component value of voltage are obtained based on 3S / 2R transformation; a feedback function is constructed, with making Q be equal to 0 as an objective, an angle correction value is mapped into a computer timing break point, a timing interruption number where a corrected angle is located and the relative positions of precise time during two times of interruption are solved; an operation result is mapped into the virtual sinusoidal signals, so that a phase-locking angle can be obtained; phase compensation is performed for the angle; the integer part and fractional part of a zero-crossing point generated by the operation result are recorded, a frequency operation counter is updated until a next zero-crossing point is generated, the difference of the integer parts and the difference of the fractional parts of the two zero-crossing points are calculated, and the difference of the integer parts and the difference of the fractional parts are multiplied by a timing interruption period, so that accurate frequency can be obtained. The high-precision anti-interference fixed-point computer three-phase voltage frequency measurement phase-locking algorithm of the invention has the advantages of wide application range, accurate calculation result and high calculation speed.

Description

technical field [0001] The invention discloses a three-phase voltage frequency measurement phase-locking algorithm for a high-precision anti-interference fixed-point computer, which relates to the technical field of three-phase AC voltage phase-locking and frequency acquisition, and more specifically, relates to a fast phase-locking method suitable for a high-precision fixed-point computer and frequency acquisition methods. Background technique [0002] Existing AC phase-locked frequency measurement methods usually include the following: [0003] 1. The hardware phase-locked loop frequency measurement circuit method, which is limited by the hardware design capability, often requires an external circuit with a high attenuation value and a low-pass filter, and also requires a high-demand power circuit, which requires high circuit design and increases cost. [0004] 2. Fourier decomposition method. Phase and frequency results can be obtained based on discrete Fourier decompos...

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Problems solved by technology

[0003] 1. The hardware phase-locked loop frequency measurement circuit method, which is limited by the hardware design capability, often requires an external circuit with a high attenuation value and a low-pass filter, and also requires a high-demand power circuit, which requires high circuit design and increases cost

[0004] 2. Fourier decomposition method, based on discrete Fourier decomposition algorithm, can obtain phase and frequency results, but discrete Fourier decomposition requires a lot of calculations, and ordinary cheap fixed-point single-chip microcomputers / DSPs are difficult to achieve fast calculations, so there are great limitations

[0005] 3. Software zero-crossing detection, the circuit is simple and the algorithm is simple, but when encountering interference, the zero-crossing point is easily disturbed, and it is difficult to be widely used in practical applications

[0006] There is a lack of a fast phase-locking and frequency acquisition method for high-precision fixed-point computers in the prior art

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