CN-116470471-B - Frequency converter protection circuit and frequency converter

CN116470471BCN 116470471 BCN116470471 BCN 116470471BCN-116470471-B

Abstract

The invention relates to the field of frequency converters. The invention discloses a frequency converter protection circuit and a frequency converter, wherein the frequency converter protection circuit is connected between the frequency converter and a power supply, a contactor KM1 is connected in series in a starting circuit, the input end of a fault reporting circuit is connected with a first terminal K1 of the frequency converter, the output end of the fault reporting circuit is connected with a power supply N line, the input end of the starting circuit is connected with a second terminal K2 of the frequency converter, the output end of the starting circuit is connected with the power supply N line, the starting circuit and the fault reporting circuit are connected in parallel, when the fault reporting circuit receives a fault signal, the first terminal K1 is closed, the second terminal K2 is opened, a normally open contact of the contactor KM1 is opened, and the frequency converter is stopped. According to the invention, by arranging the contactor KM1, when a fault occurs, normally open contacts of the contactor KM1 are all disconnected, so that the connection between an external circuit and the frequency converter can be cut off, and the fault voltage is prevented from entering the frequency converter, so that the damage of internal elements of the frequency converter is avoided.

Inventors

YANG XULONG
HE JIANFENG
ZHONG LIANG
DENG ZONGQUAN

Assignees

华能安源发电有限责任公司

Dates

Publication Date: 20260512
Application Date: 20230427

Claims (7)

1. A frequency converter protection circuit is connected between a frequency converter and a power supply, and is characterized in that, The device comprises a contactor KM1, a starting circuit and a fault reporting circuit; the contactor KM1 is connected in series in the starting circuit; The input end of the fault reporting circuit is connected with a first terminal K1 of the frequency converter, and the output end of the fault reporting circuit is connected with a power N line; The input end of the starting circuit is connected with the second terminal K2 of the frequency converter, the output end of the starting circuit is connected with a power N line, and the starting circuit and the fault reporting circuit are connected in parallel; When the starting circuit receives a starting signal, the first terminal K1 is opened, the second terminal K2 is closed, the normally open contact of the contactor KM1 is closed, and the frequency converter is started; when the fault signal is received by the fault reporting circuit, the first terminal K1 is closed, the second terminal K2 is opened, the normally open contact of the contactor KM1 is opened, and the frequency converter is stopped; The starting circuit comprises a pre-starting module; The first end of the second terminal K2 of the frequency converter is connected with a power supply L line, the second end of the second terminal K2 of the frequency converter is connected with the input end of the pre-starting module, the output end of the pre-starting module is connected with the power supply N line, the second terminal K2 of the frequency converter, the first normally open contact of the contactor KM1 and the coil of the contactor KM1 are connected in series, and the second end of the coil of the contactor KM1 is used as the output end of the pre-starting module; the pre-starting module comprises a first switch SA1; The first normally open contact of the contactor KM1 is connected with the first switch SA1 in parallel to form a first self-locking circuit; the starting circuit comprises a starting module; the input end of the starting module is connected with a power supply L line, the output end of the starting module is connected with a power supply N line, and the second normally open contact of the contactor KM1 is connected in series in the starting module; the output end of the frequency converter is connected with the input end of the motor; the third normally open contact of the contactor KM1 is connected in series in a connection circuit of the frequency converter and the motor.
2. The frequency converter protection circuit of claim 1, wherein, The pre-starting module further comprises a second switch SB1; the second terminal K2 of the frequency converter, the first normally open contact of the contactor KM1, the second switch SB1 and the coil of the contactor KM1 are connected in series.
3. The frequency converter protection circuit of claim 1, wherein, The starting module further comprises a relay KA1 and a third switch SA2; The first normally open contact of the relay KA1, the second normally open contact of the contactor KM1 and the coil of the relay KA1 are connected in series, and the second end of the coil of the relay KA1 is used as the output end of the starting circuit; the first normally open contact of the relay KA1 is connected with the third switch SA2 in parallel to form a second self-locking circuit; the frequency converter further comprises an internal starting module, wherein the input end and the output end of the internal starting module are respectively connected with two starting terminals of the frequency converter; the second normally open contact of the relay KA1 is connected in series in the internal starting module.
4. A frequency converter protection circuit according to claim 3, wherein, The starting module further comprises a fourth switch SB2; the first normally open contact of the relay KA1, the fourth switch SB2, the second normally open contact of the contactor KM1 and the coil of the relay KA1 are connected in series.
5. The frequency converter protection circuit of claim 1, wherein, The fault reporting circuit further comprises a relay KA2; The first end of the first terminal K1 of the frequency converter is connected with a power supply L line, the second end of the first terminal K1 of the frequency converter is connected with the input end of the fault reporting circuit, and the output end of the fault reporting circuit is connected with the power supply N line; The second end of the first terminal K1 is connected with the coil of the relay KA2 in series, the second end of the coil of the relay KA2 is used as the output end of the fault reporting circuit, and the relay KA2 is used for reporting fault indication to the DCS.
6. A frequency converter to which a frequency converter protection circuit according to any one of claims 1-5 is connected.
7. The frequency converter according to claim 6, wherein the frequency converter comprises, The frequency converter is connected with the motor; The motor is connected with an electromagnetic braking device; the electromagnetic braking device is connected with a power supply through a rectifier.

Description

Frequency converter protection circuit and frequency converter Technical Field The invention relates to the field of frequency converters, in particular to a frequency converter protection circuit and a frequency converter. Background The frequency converter is used for adjusting the voltage and frequency of the output power supply by switching on and off the internal IGBT, and providing the required power supply voltage according to the actual requirement of the motor, so as to achieve the purposes of energy saving and speed regulation. Along with the continuous improvement of the industrial automation degree, the frequency converter is widely applied. However, in the process of implementing the invention, at least the following problems are found in the prior art that when the frequency converter itself fails or other electrical components connected with the frequency converter fail, the failure voltage still enters the frequency converter, so that the internal components of the frequency converter are damaged. Disclosure of Invention In view of the above, the present invention provides a protection circuit for a frequency converter and the frequency converter. Specifically, the method comprises the following technical scheme: In one aspect, a frequency converter protection circuit is provided, connected between a frequency converter and a power supply, The device comprises a contactor KM1, a starting circuit and a fault reporting circuit; the contactor KM1 is connected in series in the starting circuit; The input end of the fault reporting circuit is connected with a first terminal K1 of the frequency converter, and the output end of the fault reporting circuit is connected with a power N line; The input end of the starting circuit is connected with the second terminal K2 of the frequency converter, the output end of the starting circuit is connected with a power N line, and the starting circuit and the fault reporting circuit are connected in parallel; When the starting circuit receives a starting signal, the first terminal K1 is opened, the second terminal K2 is closed, the normally open contact of the contactor KM1 is closed, and the frequency converter is started; When the fault signal is received by the fault reporting circuit, the first terminal K1 is closed, the second terminal K2 is opened, the normally open contact of the contactor KM1 is opened, and the frequency converter is stopped. Preferably, the starting circuit comprises a pre-starting module; The first end of the second terminal K2 of the frequency converter is connected with a power supply L line, the second end of the second terminal K2 of the frequency converter is connected with the input end of the pre-starting module, the output end of the pre-starting module is connected with the power supply N line, and the second terminal K2 of the frequency converter, the first normally open contact of the contactor KM1 and the coil of the contactor KM1 are connected in series; the pre-starting module comprises a first switch SA1; the first normally open contact of the contactor KM1 and the first switch SA1 are connected in parallel to form a first self-locking circuit. Preferably, the pre-starting module comprises a second switch SB1; the second terminal K2 of the frequency converter, the first normally open contact of the contactor KM1, the second switch SB1 and the coil of the contactor KM1 are connected in series. Preferably, the starting circuit comprises a starting module; the input end of the starting module is connected with a power supply L line, the output end of the starting module is connected with a power supply N line, and the second normally open contact of the contactor KM1 is connected in series in the starting module. Preferably, the starting module comprises a relay KA1 and a third switch SA2; the first normally open contact of the relay KA1, the second normally open contact of the contactor KM1 and the coil of the relay KA1 are connected in series; the first normally open contact of the relay KA1 is connected with the third switch SA2 in parallel to form a second self-locking circuit; The frequency converter comprises an internal starting module, and the input end and the output end of the internal starting module are respectively connected with two starting terminals of the frequency converter; the second normally open contact of the relay KA1 is connected in series in the internal starting module. Preferably, the starting module further comprises a fourth switch SB2; the first normally open contact of the relay KA1, the fourth switch SB2, the second normally open contact of the contactor KM1 and the coil of the relay KA1 are connected in series. Preferably, the fault reporting circuit comprises a relay KA2; The first end of the first terminal K1 of the frequency converter is connected with a power supply L line, the second end of the first terminal K1 of the frequency converter is connected with the input end of the fault