Linearized optical signal transmission system of electronic transformer

Abstract

The invention discloses a linearized optical signal transmission system of an electronic transformer, and belongs to the technical field of electrical engineering measurement. The high-voltage side and the low-voltage side are connected through a transmission optical fiber, and the system is characterized in that an electro-optical conversion module comprises a feedback control module; the feedback control module controls a transmission light-emitting diode and a feedback light-emitting diode to flow through driving currents with the same magnitude, and an optical signal emitted by the transmission light-emitting diode is connected with an interface, located on the high-voltage side, of the transmission optical fiber; a feedback loop is further arranged on the high-voltage side, optical signals emitted by the feedback light-emitting diode are converted into feedback voltage through the feedback loop, and the feedback voltage is connected with the other input end of the feedback controlmodule. According to the linearized optical signal transmission system of the electronic transformer, the feedback control module and the feedback loop connected with the feedback control module arearranged, so the size to be measured on the high-voltage side is linearly expressed through the luminous intensity of the light emitting diode, the complexity of the system is reduced, and the reliability is higher.

Description

technical field [0001] The invention relates to a linearized optical signal transmission system of an electronic transformer, which belongs to the technical field of electrical engineering measurement. Background technique [0002] In the field of electrical measurement, due to the advantages of optical fiber with good insulation performance, wide frequency band, and anti-interference, the electrical information (such as voltage and current) collected on the high-voltage side is converted into optical signals and transmitted to the low-voltage side by optical fiber. In the current technical application, there are mainly two ways to transmit optical signals through optical fibers: digital optical signal mode and analog optical signal mode. The analog optical signal method has the following advantages over the digital optical signal: First, since there is no need for A / D sampling on the high voltage side, it can completely retain the waveform information of the high voltage to...

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Problems solved by technology

and further by Image 6 It can be seen that the method directly drives the light-emitting diode, which is limited by the light-emitting mechanism of the light-emitting diode, and there is a light-emitting dead zone, so the input current of the light-emitting diode has a nonlinear relationship with the output optical power, so this scheme has not been realized. Linear Transmission of Signals

[0004] (2) The technical solution disclosed in the Chinese patent with the application number 201410379248.3 and the patent name "Analog Electrical Signal Transmission Method Applied to Current Transformers" also adopts the design of directly driving light-emitting diodes to emit light, and discloses that a DC reference The signal processing method that the signal is transmitted together with the signal to be measured is used to correct the influence of attenuation and external factors on the analog optical signal to improve the measurement accuracy, but these methods do not consider solving the nonlinear problem of light emitting diodes, so it is difficult to achieve high precision

[0005] (3) The application number is 201410379248.3, the patent name is "analog electrical signal transmission method applied to current transformer", the application number is 201510102017.2 and the patent name is "a signal transmission method for current transformer" Chinese patent document In the disclosed technical method, the design scheme of directly driving the light-emitting diode to emit light is also adopted. In addition to not realizing the linear transmission of the signal, the technical scheme also needs to measure and calibrate each set of devices in advance, and the workload is relatively large. Therefore, its application It is difficult to achieve high measurement accuracy when

The common disadvantage is that it is necessary to design a light-emitting diode device with monitoring function, which leads to high system cost, and the method of increasing the compensation amount of the DC reference signal makes the realization of the system difficult

This method has the following disadvantages: 1) This scheme needs to realize relatively accurate compensation control, the accuracy of analog / digital conversion and digital / analog conversion must be high, so the number of digits of A / D and D / A conversion must be high, ordinary 8-bit A / D and D / A cannot meet the requirements, which will lead to higher cost of CPU or peripheral A / D and D / A

2) In this method, the CPU needs to perform synchronous sampling of the two signals, and the price of the synchronous sampling A / D chip is relatively high

3) This method involves the CPU's least squares fitting operation, division operation, size comparison operation, and loop operation including the above operations for multiple sets of sampling data points, so the CPU has a large amount of calculation

Since the measurement requirement of the current transformer in the power system is to measure each cycle, this method requires the CPU to perform the above calculations in each cycle, and the CPU must complete the above operations at a high speed. Ordinary single-chip microcomputers are not competent and must be used. Realized by high-performance single-chip microcomputer or DSP processor

This will result in a system with very high cost and power

4) This scheme is used in the design of active electronic current transformers. In the design of active electronic current transformers, the power supply design technology on the high-voltage side is also a difficult technology to overcome. It is required that the power consumption of the high-voltage side circuit be as low as possible. The problem of power consumption on the high-voltage side is not only related to cost, but also related to the reliability of the system, and it is difficult to meet the low power consumption requirements when implementing this solution

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