Parallel frequency converter control circuit of high-power compressor motor

Abstract

The parallel frequency converter control circuit of the high-power compressor motor comprises a first frequency converter and a second frequency converter which are arranged in parallel, the output sides of the first frequency converter and the second frequency converter are respectively connected with the input side of a parallel reactor, and the output side of the parallel reactor is connected with the motor; a third circuit breaker is arranged between the shunt reactor and the motor; a standby bypass is further connected between the bus and the motor, and a fourth circuit breaker is installed on the standby bypass. By means of synchronous control of the first frequency converter and the second frequency converter, normal production can be guaranteed under the condition of light faults of the frequency converters, the mode of switching bypass power frequency operation control is achieved, normal operation of a compressor can still be guaranteed when one frequency converter breaks down heavily, the shutdown time or load reduction operation of a production system is shortened to the maximum extent, and the production efficiency is improved. And production safety and equipment safety are ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of frequency converter control, specifically relates to a parallel frequency converter control circuit of high -power compressor motor. BACKGROUND

[0002] In the methanol synthesis, the role of methanol synthesizer compressor is to send to the methanol synthesizer after the raw material gas pressurization to certain pressure, and its power is 19000KW. Generally, the compressor motor uses soft starter to start, and uses guide vane to adjust raw material gas flow, which needs a large amount of electric energy to drive, and cannot meet the large flow change in the sudden situation in production, so as to ensure that the large flow change in production can be met, at present, frequency converter is used to drive the motor, but once the frequency converter fails, the compressor cannot work, if light failure occurs, the frequency converter will reduce 14% load, therefore, the normal operation of frequency converter or the reduction of frequency converter load rate has great significance to production. UTILITY MODEL CONTENTS

[0003] The utility model discloses a parallel frequency converter control circuit of high -power compressor motor.

[0004] The utility model discloses the following technical scheme implementation:

[0005] A parallel frequency converter control circuit of high -power compressor motor, including the parallelly connected first frequency converter and second frequency converter, the input side of first frequency converter and second frequency converter all are connected with bus, the output side of first frequency converter and second frequency converter are connected with the input side of shunt reactor respectively, the output side of shunt reactor is connected with motor;

[0006] First circuit breaker is installed between the first frequency converter and the bus, second circuit breaker is installed between the second frequency converter and the bus, third circuit breaker is installed between the shunt reactor and the motor;

[0007] The bus and the motor are also connected with standby bypass, and fourth circuit breaker is installed on the standby bypass.

[0008] Preferably, the first circuit breaker and the first frequency converter are connected with the excitation inrush current suppression cabinet, and the second circuit breaker and the second frequency converter are connected with the excitation inrush current suppression cabinet.

[0009] Preferably, the first frequency converter and the second frequency converter contain multiple power modules and are equal in number.

[0010] The utility model discloses a advantage: through the first frequency converter and the second frequency converter synchronous control, ensure that frequency converter light failure can guarantee normal production under, and have the switching bypass power frequency operation control mode, still can ensure compressor normal operation when one frequency converter occurs heavy failure, maximum degree reduces the parking time or the load reduction operation of production system, ensures production safety and equipment safety. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is the structural schematic diagram of the utility model;

[0012] Figure 2 It is the structural schematic diagram of the power unit in the first frequency converter and the second frequency converter.

[0013] In the drawing: first frequency converter 1, second frequency converter 2, bus 3, shunt reactor 4, motor 5, first circuit breaker 6, second circuit breaker 7, third circuit breaker 8, standby bypass 9, fourth circuit breaker 10, excitation inrush current suppression cabinet 11. DETAILED DESCRIPTION

[0014] As Figure 1 And Figure 2 Shown in the drawing, a kind of parallel connection frequency converter control circuit of high-power compressor motor, including the parallel connection of first frequency converter 1 and second frequency converter 2, the input side of first frequency converter 1 and second frequency converter 2 are connected with bus 3, the output side of first frequency converter 1 and second frequency converter 2 are connected with the input side of shunt reactor 4 respectively, and the output side of shunt reactor 4 is connected with motor 5;First circuit breaker 6 is installed between first frequency converter 1 and bus 3, second circuit breaker 7 is installed between second frequency converter 2 and bus 3, and third circuit breaker 8 is installed between shunt reactor 4 and motor 5;Standby bypass 9 is also connected between bus 3 and motor 5, and fourth circuit breaker 10 is installed on standby bypass 9;First frequency converter 1 and second frequency converter 2 include multiple power modules and equal in number in it.

[0015] Under normal operation, first circuit breaker 6, second circuit breaker 7 and third circuit breaker 8 are all closed state, and fourth circuit breaker 10 is open state, and motor 5 is driven to operate by first frequency converter 1 and second frequency converter 2, and taking 12500KW compressor as an example, the power of motor 5 is 12500KW, and after being driven by parallel connection first frequency converter 1 and second frequency converter 2, the driving power can reach 12500KW*2 at most;

[0016] The phase-shifting transformers of the first frequency converter 1 and the second frequency converter 2 and the eight power units of the A phase, the B phase and the C phase work simultaneously, when the module of any power unit of the first frequency converter 1 fails, the power units of the same position of the first frequency converter 1 are shielded together, for example, when the module of the phase-shifting transformer APVa4 of the first frequency converter 1 fails, the phase-shifting transformer APVa4 of the second frequency converter 2 is shielded together with the module, that is, when the power unit module of the first frequency converter 1 sends a light failure alarm, at this time the frequency converter should bear 7%, by shielding the corresponding power unit modules of the two together, so the load reduction is 2x12500KW under the condition of 7% load reduction, therefore the synthetic compressor can still output 100% load, which can ensure the production requirement;

[0017] When one of the first frequency converter 1 or the second frequency converter 2 has a heavy failure such as frequency converter overheating, heavy failure of the frequency converter power unit, etc., the soft start function of the frequency converter is used to start, after the motor 5 is started, the first circuit breaker 6, the second circuit breaker 7 and the third circuit breaker 8 are all disconnected, the fourth circuit breaker 10 is closed, so that the motor is changed to work at the power frequency, the guide vane opening of the compressor is adjusted according to the production load condition, and the production requirement can still be met.

[0018] The parallel reactor 4 is used to prevent the electric energy impact of the two frequency converters when the frequency difference between the first frequency converter 1 and the second frequency converter 2 is large.

[0019] The excitation inrush current suppression cabinet 11 is connected between the first circuit breaker 6 and the first frequency converter 1 and between the second circuit breaker 7 and the second frequency converter 2, the inrush current suppressor is installed in the excitation inrush current suppression cabinet 11, and the excitation inrush current suppression cabinet 11 is used to suppress the excitation inrush current generated when the circuit is switched on and off, and the frequency converter and the motor 5 are protected.

[0020] The above only describes the preferred embodiments of the utility model, and does not limit the utility model, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A parallel inverter control circuit for a high power compressor motor, characterized by, The first frequency converter and the second frequency converter are connected with a bus at input sides, and the output sides of the first frequency converter and the second frequency converter are connected with input sides of a parallel reactor respectively, and the output side of the parallel reactor is connected with a motor; A first circuit breaker is installed between the first frequency converter and the bus, a second circuit breaker is installed between the second frequency converter and the bus, and a third circuit breaker is installed between the parallel reactor and the motor; A standby bypass is further connected between the bus and the motor, and a fourth circuit breaker is installed on the standby bypass.

2. A parallel variable frequency drive control circuit for a high power compressor motor as set forth in claim 1, characterized in that, A magnetizing inrush current suppression cabinet is connected between the first circuit breaker and the first frequency converter and between the second circuit breaker and the second frequency converter.

3. A parallel variable frequency drive control circuit for a high power compressor motor as set forth in either of claims 1 or 2, characterized by, The first frequency converter and the second frequency converter contain an equal number of power modules.

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