Power grid voltage phase detection method based on optocoupler

Abstract

The invention is applicable to the field of voltage phase detection, and provides a power grid voltage phase detection method based on an optocoupler, which comprises the following steps: S1, detecting a time difference between two adjacent rising edges of the optocoupler by using a capture timer, and calculating the power grid frequency of alternating voltage; S2, detecting a time difference between two adjacent rising edges and falling edges of the optocoupler by using a capture timer, and calculating a power grid phase offset between the phase of the power grid and the rising edges of the optocoupler by using two points on a sine function; and S3, smoothing the calculated voltage phase through a phase-locked loop, and taking a phase angle obtained through the phase-locked loop as a final detection result to obtain a final estimation angle. The defects that in the prior art, an analog-to-digital converter method is used, cold and hot ground separation cannot be achieved, an analog-to-digital converter is needed, the operand is large, and the disturbance rejection capacity is poor are overcome; an optical coupling method is used for detecting phase delay, and the adaptability to amplitude and frequency changes of an alternating current power grid is poor.

Description

technical field [0001] The invention belongs to the field of grid voltage phase detection, in particular to an optocoupler-based grid voltage phase detection method. Background technique [0002] The grid is an AC power source characterized by periodic changes in magnitude and direction over time. In practical applications, in order to achieve the purpose of adjusting the output power, it is necessary to perform chopping processing such as partial cutoff and periodic cutoff of the AC grid. Thyristors and relays are common electronic components used for chopping, which have the advantages of simple driving, low cost and wide adaptability. However, when the AC voltage peak is turned on or off, a relatively large current impact will be generated on the thyristor and the relay, causing damage to the thyristor and the relay, shortening their service life, and even causing them to burn out. Therefore, it is necessary to perform chopping processing near the zero-phase point of th...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a grid voltage phase detection method based on optocouplers, which aims to solve the problem that the AC voltage phase detection methods in the prior art are mainly divided into two categories, one is the analog-to-digital converter method, and this method has problems Realize the separation of hot and cold, require analog-to-digital converters, large amount of calculation, poor anti-disturbance ability and other shortcomings; one is the use of optocoupler method, which has detection phase delay and poor adaptability to the amplitude and frequency changes of the AC power grid technical issues

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