CN2262306Y

CN2262306Y - Exciting cabinet for high efficiency energy saving synchronous motor

Info

Publication number: CN2262306Y
Application number: CN 96234487
Authority: CN
Inventors: 邱进; 韦伟平
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-03-27
Filing date: 1996-03-27
Publication date: 1997-09-10
Anticipated expiration: 2006-03-27

Abstract

The utility model relates to a high efficiency and energy saving excitation cabinet for synchronous motors, which is an excitation device for synchronous motors. The utility model solves the problems of multiple fault and low stability in existing excitation devices. The utility model is characterized in that the output of a full bridge inverter circuit connected with a rectification and filtering circuit is connected with a motor excitation winding through the rectification and filtering circuit and an excitation loop; a main control circuit outputs four control signals to respectively control four switch pipes of the inverter circuit; an excitation throwing circuit tests the voltage signal of the excitation winding and outputs excitation throwing signals to a gate closing loop of a main switch. The utility model has the advantages of simple structure, low cost, stable operation, and energy saving. The utility model is suitable for various synchronous motors for excitation.

Description

Energy-efficient synchronous machinery excitation cabinet

The utility model relates to a kind of excitation unit of synchronous machine.

Synchronous motor uses in industrial enterprise in a large number at present, it is the important motivity equipment in the industries such as chemical fertilizer, petrochemical industry, machinery, metallurgical building materials, pharmacy, coal gas and running water, and these synchronous machines in using damage mainly be since the too poor institute of supporting with it excitation unit performance extremely, the present excitation cubicle that uses, consistent employing linear transformation technology over 40 years, frequency is lower, the cabinet heaviness, the performance extreme difference, efficient is too low, therefore the too big and high factor that heats up of power consumption causes operating frequency to be in the noise range, and operation is unstable.

The purpose of this utility model is to provide a kind of energy consumption low, reliable energy-efficient synchronous machinery excitation cabinet.

The utility model is finished with following mode: energy-efficient synchronous machinery excitation cabinet, it comprises current rectifying and wave filtering circuit, the full bridge inverter output that is connected to current rectifying and wave filtering circuit connects the synchronous electric motor rotor winding through current rectifying and wave filtering circuit and magnetism elimination circuit, full bridge inverter is by the control signal control of governor circuit output, throwing is encouraged control circuit and is connect the synchronous electric motor rotor winding through sample resistance Rx, throws the closing circuit of encouraging control circuit output control signal control synchronous machine main power switch.Full bridge inverter is made up of insulated gate bipolar transistor T1, T2, T3, the T4 of controlled break-make, be parallel with fly-wheel diode on the collector electrode of the insulated gate bipolar transistor of each controlled break-make and emitter, its base stage connects the control signal of governor circuit output.Governor circuit is that the output of integrated circuit (IC) 2 connects the base stage of two switch triodes respectively by input termination sample circuit and the protective circuit of integrated circuit (UPC494) IC2, exports four tunnel control signals through two transformer B3, B4.Throwing is encouraged after shaping circuit that circuit is made up of integrated amplifier IC5 accepts the signal of telecommunication of synchronous electric motor rotor winding, output through with door IC4 input to monostable trigger-action circuit IC6 and through not gate IC8 to door IC9, the input and output of monostable trigger-action circuit IC6 connect and constitute a frequency detection circuit with door IC4 and export single stabilization delay circuit IC7 to and input to and a door IC9 again, export the base stage that meets switch transistor T R with door IC9, the collector series relay TL of switch transistor T R, the normal opened contact of relay TL is connected to the switch closing circuit.

The energy-efficient synchronous machinery excitation cabinet of the utility model is owing to adopt the insulated gate bipolar transistor composition full bridge inverter adjusting exciting current that governor circuit is controlled controlled break-make, so its volume is little, in light weight, its full-bridge inverting frequency reaches 20KHZ, noise is low, temperature rise is little, but the efficient of complete machine device this more than 85%, and need not any additional heat equipment, this excitation cubicle is stable, reliably, voltage stabilized range is wide, and convenient for maintaining is compared with old-fashioned excitation cubicle, its economize on electricity can reach 30%-60%, it has simple in structure, and cost is low, and it is a kind of comparatively ideal synchronous machinery excitation cabinet.

Fig. 1 is the utility model circuit theory diagrams.

Fig. 2 is that circuit theory diagrams are encouraged in the utility model throwing.

Fig. 3 is the utility model governor circuit schematic diagram.

Fig. 4 is the utility model out-of-step protection circuit schematic diagram.

Below in conjunction with accompanying drawing the utility model is described in further detail:

The energy-efficient synchronous machinery excitation cabinet of the utility model is applicable to synchronous motor and synchronous generator.When being used for synchronous motor, when closing synchronous motor electric power loop main switch, synchronous motor enters the asynchronous starting process, excitation winding has positive and negative alternation induced voltage, in this process, throwing is encouraged circuit and by testing circuit motor is detected, when motor enters metasynchronism, circuit operation is encouraged in throwing, electric network source obtains DC power supply after by current rectifying and wave filtering circuit, obtain the 20KHZ alternating voltage through full bridge inverter then, obtain DC power supply for the synchronous electric motor rotor exciting current through rectifying and wave-filtering again.When as the field power supply of synchronous generator, only need that the testing circuit that circuit is encouraged in throwing is connected to generator speed testing circuit output in addition and get final product.

As shown in Figure 1, close a switch behind the K, when motor stator ring current switch closes, relay HZJ contact, main switch auxiliary contact DLJ is closed simultaneously, synchronous motor TD enters the asynchronous starting process, contactor CJ3 coil electricity, excitation winding has induced voltage to produce, by contact CJ3 and resistance R _ f, obtain the alternation induced current, throwing this moment is encouraged circuit and by resistance R x the motor induced voltage is detected, when motor reaches metasynchronism, circuit operation is encouraged in throwing, relay TL normal opened contact closure, relay TLJ adhesive, contactor CJ1 and CJ2 adhesive subsequently, CJ3 opens, and the asynchronous starting process finishes, and motor enters the synchronous operation state, this moment, electric network source was through contactor CJ1 contact, by rectifier bridge ZL1, and obtain DC power supply behind filter capacitor C1 and the direct rectifying and wave-filtering of C2, offer Golden Bridge's inverter circuit, full bridge inverter is by switch transistor T 1, T2, T3, T4 and the corresponding parallel diode D1 of difference, D2, D3, D4, the elementary serial connection capacitor C 3 of transformer B2 is as the load of full bridge inverter.The switch transistor T 1 of full bridge inverter, T2, T3, T4 is controlled break-make insulated gate bipolar transistor, its control utmost point base stage is connected in series the output of governor circuit respectively, main control circuit is exported two groups of pulse width variabilities, the pulse signal P1 that the phase phasic difference is 180 °, P2, P3, P4 controls T1 respectively, T2, T3, the opening and turn-offing of T4 pipe, by T1, T4 pipe and T2, T3 pipe exchange conducting obtains the 20KHZ alternating voltage, the secondary serial connection diode D5 of transformer B2 and D6 constitute commutating circuit through inductance L filtering, obtain DC power supply, the magnetism elimination circuit through contactor contact CJ2 and CJ3 composition connects the synchronous electric motor rotor winding again.Main control circuit as shown in Figure 3, it is to be exported+the 5V reference voltage by 14 pin of integrated circuit (UPC494) IC2, through resistance R 22,2 pin that offer IC2 after the R23 dividing potential drop are sent into the negative input end of the error amplifier of IC2, by sample circuit R6, W, R7 series connection dividing potential drop inputs to the A end (i.e. 1 pin) of IC2, be fed through the positive input terminal of the error amplifier of IC2, sampled voltage signal and reference voltage signal compare and enlarge in the error amplifier of IC2, output error voltage, size according to error, change the width of IC2 output driving pulse, thereby change the pulse duration of his exciting converter, and obtain different output voltages.Resistance R 17 serial connection R20 dividing potential drops are supplied with fixed voltage of 4 pin of IC2, determine the time in dead band, guarantee that switch transistor T 1, T4 and T2, T3 do not have common ON time, and 3 pin of IC2 connect capacitor C 3, C4 and resistance, are used for weakening and proofread and correct usefulness.Output 8 pin of IC2 and the output of 11 pin connect the base stage of switch transistor T 5 and T6 respectively, the collector electrode of switch transistor T 5 and T6 is the primary coil of series transformer B3 and B4 respectively, B3 and B4 secondary have respectively two groups of two groups of windings output control signal P1, P4 and P3, P2 mutually the pulse signal of 180 ° of phasic differences connect the control utmost point of switch transistor T 1, T4 and T3, T2.Throwing is encouraged circuit as shown in Figure 2, it forms shaping circuit by voltage-stabiliser tube DW, resistance R 7, R8 and diode D2 and integrated operational amplifier IC5 (LM393), alternating voltage signal via the detected motor excitation winding of Rx is carried out the square wave that shaping obtains frequency change, by resistance R 15, R14, capacitor C 1 and not gate IC3 (40106) form closed circuit link, when the HZJ adhesive, IC3 input current potential becomes electronegative potential by high potential, becomes high potential through the IC3 not gate and inputs to and door IC4 (4071).Remove to throw and encourage circuit interlocking, the square-wave signal warp of shaping circuit output and door IC4 input to by monostable integrated circuit (IC) 6 (4538) and capacitor C 21 and resistance R 30 reaches and a door IC42 (4071) constitutes frequency detection circuit, after inputing to delay circuit after the detection frequency by monostable integrated circuit (IC) 7 (4538) and capacitor C 31 and resistance R 31 formations, through exporting the base stage of switch transistor T R to door IC9 (4071), square wave after the shaping inputs to and door IC9, the collector electrode of relay TL coil tandem switch transistor T R through not gate IC8 (40106).Electric circuit inspection is encouraged in throwing, and to differentiate the course of work of synchronous machine frequency be through the rising along with motor speed of the alternation square wave of IC4 shaping output, its frequency is more and more littler, setting-up time when alternation rectangle wave period greater than frequency detection circuit IC6, the Q end of IC6, just export high level, otherwise output low level then, the setting-up time of IC6 is 0.3 second to 0.5 second.When IC6 exports high potential and IC42 and exports high potential behind the door, through single stabilization delay circuit delay time broad pulse of output to door IC9, the alternation square wave of the output of IC4 shaping simultaneously inputs to and a door IC9 behind the door through IC8 is non-, when the high potential of the alternation square wave of not gate IC8 output, with the base stage of door IC9 output high potential to switch transistor T R, TR conducting, TL adhesive, its contact TL throws the process of encouraging and finishes to the control loop that closes a floodgate.

The protection loop is provided with overcurrent protection, overvoltage protection, loss of synchronism protection.Overcurrent protection such as Fig. 1, shown in Figure 3; BC two ends from current transformer TEST output detectable voltage signals to main control loop are when the BC both end voltage increases; input to 5,6 pin of IC2; the control amplifier output voltage of IC2 is raise; the pulse duration of IC2 output is reduced greatly, limited the rising of electric current.Overvoltage protection such as Fig. 1, shown in Figure 3 are connected to the control utmost point of voltage stabilizing didoe DW1 minute crimping controllable silicon KG from the D point, and after voltage raise, DW1 punctured, and the KG conducting makes the switch transistor T conducting, and the 4 pin current potentials of IC2 are raise, and make power remove.Loss of synchronism protection such as Fig. 1, shown in Figure 4; the exciting voltage that measures from Rx; through the G point to main control circuit F point; promptly through voltage-stabiliser tube DW2; resistance R 35; capacitor C 9; resistance R 36, capacitor C 10 be to the negative terminal of operational amplifier IC10, when voltage is lower than resistance R 26 serial connection potentiometer W dividing potential drops and exports the positive terminal voltage of IC10 to; show motor desynchronizing; IC10 output high potential is to switch transistor T 7 base stages, and the T7 conducting is connected in series the relay TZ adhesive of its collector electrode; its normal opened contact TZJ is closed to major loop switch trip loop, the protection motor.

Claims

1. energy-efficient synchronous machinery excitation cabinet, it comprises current rectifying and wave filtering circuit, it is characterized in that the full bridge inverter output that is connected to current rectifying and wave filtering circuit connects the synchronous electric motor rotor winding through current rectifying and wave filtering circuit and magnetism elimination circuit, full bridge inverter is by the control signal control of governor circuit output, throwing is encouraged control circuit and is connect the synchronous electric motor rotor winding through sample resistance Rx, throws the closing circuit of encouraging control circuit output control signal control synchronous machine main power switch.

2. according to the energy-efficient synchronous machinery excitation cabinet of claim 1 speed, it is characterized in that full bridge inverter is made up of insulated gate bipolar transistor T1, T2, T3, the T4 of controlled break-make, be parallel with fly-wheel diode on the collector electrode of the insulated gate bipolar transistor of each controlled break-make and emitter, its base stage connects the control signal of governor circuit output.

3. according to the described energy-efficient synchronous machinery excitation cabinet of claim 1; it is characterized in that governor circuit is input termination sample circuit and the protective circuit by integrated circuit (UPC494) IC2; the output of integrated circuit (IC) 2 connects the base stage of two switch triodes respectively, exports four tunnel control signals through two transformer B3, B4.

4. according to the described energy-efficient synchronous machinery excitation cabinet of claim 1, it is characterized in that throwing and encourage after shaping circuit that circuit is made up of integrated amplifier IC5 accepts the signal of telecommunication of synchronous electric motor rotor winding, output through with door IC4 input to monostable trigger-action circuit IC6 and through not gate IC8 to door IC9, the input and output of monostable trigger-action circuit IC6 connect and constitute a frequency detection circuit with door IC4 and export single stabilization delay circuit IC7 to and input to and a door IC9 again, export the base stage that meets switch transistor T R with door IC9, the collector series relay TL of switch transistor T R, the normal opened contact of relay TL is connected to the switch closing circuit.