Automatic constant current pure resistive alternating current load

Abstract

The invention relates to an automatic constant current pure resistive alternating current load. The load comprises a voltage transformer, a sampling current transformer, a rectifier bridge, a first resistor, a second resistor, a variable power resistor, a multiplier, an operational amplifier and a linear full-wave rectifier. The secondary voltage output of the voltage transformer is connected to the input of the rectifier bridge through the primary coil of the sampling current transformer. The one end of the output of the rectifier bridge is grounded and the other end is connected to one end of the second resistor through the first resistor. The other end of the second resistor is connected to the drain electrode of the variable power resistor. The grid electrode of the variable power resistor is connected to the output end w of the multiplier. The input end x of the multiplier is connected to the output of the rectifier bridge. The input end y of the multiplier is connected to the secondary coil of the sampling current transformer through the operational amplifier and the linear full-wave rectifier. Compared with the prior art, by using the load of the invention, there are the following advantages that a circuit is simple and practical; and reliability is high and so on.

Description

technical field [0001] The invention relates to the field of voltage transformer precision, in particular to an automatic constant current pure resistive AC load. Background technique [0002] In the process of realizing high-precision voltage transformer measurement, there is a close relationship between the voltage accuracy delivered by the voltage transformer and the load of the voltage transformer. In the current voltage transformer application, generally by ensuring the voltage accuracy within a reasonable range within a reasonable load range, due to the uncertainty of the load, although the work within the accuracy range can be achieved, the dispersion within the accuracy range is also objective existing. Even in the case of light load, the voltage accuracy is out of tolerance because the working load exceeds the reasonable load range; especially at present, the digital energy meter is widely used, and its working load is much smaller than one-tenth of the traditional...

AI Technical Summary

Problems solved by technology

Even in the case of light load, the voltage accuracy is out of tolerance because the working load exceeds the reasonable load range; especially at present, the digital energy meter is widely used, and its working load is much smaller than one-tenth of the traditional inductive energy meter, which solves the problem of secondary The voltage drop problem also leads to high output voltage of the voltage transformer. Choosing a reasonable secondary load is an effective means to improve the accuracy of the voltage transformer and reduce the dispersion in the statistical line loss.

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