Output voltage isolation sampling circuit of high-voltage inverter

Abstract

The invention discloses an output voltage isolation sampling circuit of a high-voltage inverter. The isolation sampling circuit is composed of a resistor and divider sampling circuit, a differential amplifier conditioning circuit, an optocoupler isolation sampling circuit, and an operational amplifier conditioning circuit. The input terminal of the resistor and divider sampling circuit is connected with a voltage output terminal of a high-voltage inverter; the differential amplifier conditioning circuit is connected with the resistor and divider sampling circuit electrically; and the operational amplifier conditioning circuit is connected with the optocoupler isolation sampling circuit electrically. The voltage after processing is a voltage meeting a digital-analog signal converter sampling pin of a digital signal processing chip and is sent into a digital-analog signal converter sampling pin of a digital signal processing chip; and the digital signal processing chip carries out sampling and computing processing, so that the system is controlled to monitor the output voltage of the high-voltage inverter in real time and overvoltage protection, undervoltage protection, phase-locked bypass and other functions can be realized.

Description

technical field [0001] The invention relates to the technical field of output voltage control of high-frequency transformers, in particular to a high-voltage frequency converter output voltage isolation sampling circuit. Background technique [0002] A high-voltage inverter is a power control device that converts power frequency voltage into another frequency by using the on-off function of power semiconductor devices. As the core equipment of the electric drive system, the high-voltage frequency converter has high requirements for reliability and stability, and also has high requirements for the control algorithm of the high-voltage frequency converter, the detection and protection of each input and output. Among them, the high-voltage frequency converter's Since the output voltage detection involves 10KV high voltage, the detection method should not only ensure the accuracy, but also pay attention to the isolation of high and low voltage circuits, so as to protect the subs...

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Problems solved by technology

[0003] The most conventional method of sampling the output voltage of the high-voltage inverter is to use a voltage transformer to measure, but this method has the following disadvantages: 1. The detection accuracy is low, because the output voltage frequency of the high-voltage inverter is adjustable within the range of 0 to 50Hz , which will cause the measurement accuracy of the voltage transformer to deteriorate and affect the calculation and control of the main control unit; 2. The voltage transformer used for high-voltage measurement is generally large in size and weight. In general, this will also increase the size of the inverter accordingly, and it is not easy to install; 3. The three-phase output needs a voltage transformer to detect, and the cost is relatively high

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