KR830001750A - Inverter circuit protection system for AC motor drive - Google Patents

Abstract

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Description

Inverter circuit protection system for AC motor drive

This content is subject to disclosure, so the full text is not included.

1 is a functional block diagram of an embodiment according to the present invention. 2 is a detailed circuit diagram of an overcurrent protection device according to the present invention. Fig. 3 is a schematic diagram showing waveforms related to various parts of the overcurrent protection device of Fig. 2;

Claims (7)

It includes an inverter circuit for converting direct current into a rectangular waveform polyphase AC by a switch action of a transistor, and an inverter driving circuit for adjusting the output frequency of the inverter circuit to a predetermined value, and the AC motor is connected to the inverter circuit. In the speed control system rotated by the alternating current supplied by the inverter, a first current detection means for detecting a maximum rated current passing through a transistor constituting an inverter circuit and a second current for detecting a predetermined overcurrent value less than the maximum rated current value It is composed of a detection means, and the operation of the inverter circuit is terminated when the first current detection means responds to the maximum rated current detection, and the current flowing through the inverter circuit is determined by the second current detection means to detect the determined overcurrent value. The protection system of the inverter circuit for driving an AC motor characterized by being improved to be limited to less than a specified overcurrent value when responding. The protection system according to claim 1, wherein the first current detection means is provided on the input side of the inverter circuit, and the second current detection means is provided on the output side of the inverter circuit. The first current detection means comprises a high current value setting device, a comparator for comparing an output voltage generated by the overcurrent value setting device with a voltage proportional to a current passing through the input side of the inverter circuit, and an output signal transmitted by the comparator. A protection system according to claim 4 including a flip-flop circuit set by. The second current detection means comprises an overcurrent value setting device and a comparator for comparing an output voltage generated by the overcurrent setting position with a voltage proportional to a voltage proportional to the current passing through the output side of the inverter circuit. Protection system according to scope 1. After the inverter circuit has a first gate circuit at its input side, a second gate circuit whose input is connected to the output side of the first gate circuit, and the first gate circuit are closed, repeatedly opening the first gate circuit A patent claim comprising a hazard setting means, wherein the second gate circuit is controlled by an output signal from a first current detection means, and the first gate circuit is controlled by an output signal from a second current detection means. Protection system according to clause 1 of the scope of. The protection system according to claim 5, wherein the first gate circuit and the second gate circuit are composed of logical multiplication gates, and the setting means for repeatedly opening the first gate circuit is a combination of a pulse generator and a flip-flop. . ※ Note: It is disclosed according to the contents of the initial application.