Method of amending phase position collecting error caused by frequency variation in phased rectifier control

Abstract

The invention discloses a method of amending a phase position collecting error caused by frequency variation in phased rectifier control. The method of amending the phase position collecting error caused by frequency variation in phased rectifier control includes the following steps. Firstly, a synchronous transformer is used to achieve isolation of a power source. A network voltage signal is isolated by the synchronous transformer and waves of an obtained power source signal are filtered and undergo zero-cross detection and reforming. Higher harmonic and direct component are removed. Secondly, for a wave filtering circuit with fixed parameters and a fixed form, phase shift deviation and frequency of an input signal form a fixed function relationship, namely, a deviation value of phase shift can be fixedly determined based on the frequency of the input signal. Thirdly, according to the deviation value, a synchronous zero reference is amended so that an authentic zero-cross signal can be restored, namely, a synchronous square wave signal is obtained after calculation in a zero-cross amending method. The method of amending the phase position collecting error caused by frequency variation in phased rectifier control has the advantages of being simple in principle, simple and convenient to operate, wide in application range, capable of eliminating zero-cross errors caused by continuous frequency variation and the like.

Description

technical field [0001] The invention mainly relates to the field of thyristor phase-shift trigger control, in particular to a method for correcting phase acquisition errors caused by frequency changes in phase-controlled rectification control. Background technique [0002] The change of the output voltage and power in the thyristor phase-shift trigger control rectification system is realized by changing the control angle of the thyristor. Phase-controlled rectification uses the turn-on controllable characteristics and unidirectional conductivity of the thyristor, a semi-controlled switching device, to control the trigger phase angle of the thyristor (pulse application is deep), and controls the initial moment when the power supply voltage is sent to the load, thereby controlling the rectified voltage. . In order to meet the conduction condition of the thyristor and calculate the control angle correctly, it is necessary to obtain the zero-crossing signal when the two-pole vo...

AI Technical Summary

Problems solved by technology

However, this method has the following disadvantages: 1. The synchronous transformer is heavy and takes up a large space in the equipment; 2. The filter circuit is affected by the power frequency change and has poor versatility; 3. When the phase changes, the zero-crossing detection The method has to wait until the next zero-crossing point to detect the phase at each subsequent moment, so its dynamic performance cannot meet the requirements in some specific applications

However, this method also has the following disadvantages: 1. Although the subsequent synchronous square wave signal can be digitally filtered, it lacks a multi-phase reference comparison for single-phase control applications. If there is serious power waveform distortion, it is easy to cause excessive Zero signal is inaccurate or even wrong

2. For ultra-high voltage power supply systems, the requirements of the withstand voltage of the isolated optocoupler and response sensitivity have caused great difficulties in the selection of devices

3. Affected by the dispersion of device parameters, it is difficult to correct the zero-crossing phase error through effective means

4. It cannot meet the control applications that need to obtain other signals such as power supply amplitude

5. Due to the same zero-crossing detection method, the dynamic performance cannot meet the requirements in some specific applications

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