Direct-current energy meter

Abstract

The invention relates to a direct-current energy meter. The direct-current energy meter comprises a direct-current sampling module (1) for collecting a current signal when the electric energy meter works; a direct-current voltage sampling module (2) for acquiring a voltage signal of the energy meter; a metering module (4) for receiving the acquired current signal and the voltage signal and analyzing and converting the current signal and the voltage signal; a control module (5) which is connected with the metering module (4), and receives information transmitted by the metering module (4) and performs bidirectional data communication; and a liquid crystal display module (9) for displaying power consumption data according to the information transmitted by the control module (5). The direct-current energy meter further comprises a voltage and current isolation module (3) for isolating the sampling voltage signals and the current signals and reducing interference between the sampling voltage signals and the current signals. Compared with the prior art, the direct-current energy meter is advantageous in that an isolation chip is arranged between a voltage sampling module and a current sampling module, so that the isolation of the two can be effectively realized, and the interference between the current signal and the voltage signal is effectively reduced. The metering accuracy of the energy meter is improved. When the voltage is reversely connected, the energy meter is intact, and the safety and the universality are ensured.

Description

technical field [0001] The invention relates to the technical field of direct current measurement, in particular to a direct current electric energy meter. Background technique [0002] With the development of science and technology, DC energy meters play an increasingly important role in the fields of solar photovoltaics, electric vehicles, and trams. However, the existing DC energy meters have large errors and weak anti-interference capabilities. Once the voltage, current Misoperation and reverse connection will cause excessive voltage inside the meter, burn out the meter, and cause safety accidents in severe cases. [0003] Specifically, the DC voltage sampling module and the DC current sampling module of the existing DC electric energy meter are as follows: figure 1 As shown, the overall external wiring of the meter is as follows figure 2 As shown, under normal circumstances, the voltage loaded on the resistor R20 is about 0.6V of the turn-on voltage drop of the diode...

AI Technical Summary

Problems solved by technology

[0002] With the development of science and technology, DC energy meters play an increasingly important role in the fields of solar photovoltaics, electric vehicles, and trams. However, the existing DC energy meters have large errors and weak anti-interference capabilities. Once the voltage, current Misoperation and reverse connection will cause excessive voltage inside the meter, burn out the meter, and cause safety accidents in severe cases.

[0003] Specifically, the DC voltage sampling module and the DC current sampling module of the existing DC electric energy meter are as follows: figure 1 As shown, the overall external wiring of the meter is as follows figure 2 As shown, under normal circumstances, the voltage loaded on the resistor R20 is about 0.6V of the turn-on voltage drop of the diode VD5, and the ammeter works normally, but when the voltage is reversed by a wrong operation, the voltage loaded on the resistor R20 is far away. The voltage far exceeds its own ability to withstand, causing R20 to burn out, the meter cannot work normally, and may even cause a fire

[0004] At the same time, all DC electric energy meters need to be calibrated before leaving the factory. When the existing table body manufacturers perform calibration, there is no isolation between each meter. The calibration principle is as follows: image 3 As shown, the voltage and current of the two gauges are respectively connected in parallel and then connected to the voltage source and current source. At this time, because there is no isolation between the gauges, the voltage terminal and the current terminal of the electric energy meter are connected by resistors R11 and R12, and the corrected The more meter positions, the more resistances connecting the voltage terminal and the current terminal, and the problem of inconsistent calibration standards of each meter position due to the influence of the connection resistance R11, R12, R13, ..., R1N is more serious, that is, the difference between the meter positions of each electric energy meter is more serious. The non-isolation has a serious calibration error problem

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