Summary of the invention
The objective of the invention is to overcome the above-mentioned defective of tandem control; provide that a kind of protection equipment is not damaged, departure is little, have good man-machine interface, flexibly means of communication, easy to use, can realize remote monitoring and management, and digitized degree is high and the middle voltage electromotor chopper speed governing digital intelligence control system with stalling protection with low cost.
For achieving the above object; the present invention adopts has the middle voltage electromotor chopper speed governing digital intelligence control system of stalling protection; comprise electric motor system and governing system; described governing system comprises the uncontrollable rectifier that is connected on successively in the main circuit; boost chopper and thyristor inverter; also comprise the inversion stalling protection device that is connected between described boost chopper and the described thyristor inverter; a digital signal processor and the interior circular current controller and the programmable controller that link to each other with described digital signal processor; and by the interior circular current of interior circular current controller enforcement to described boost chopper; thyristor inverter and inversion stalling protection device are controlled; by the outer shroud speed control of described digital signal processor enforcement to governing system; by the program control of described programmable controller enforcement, the steps include: governing system and electric motor system
(1) described digital signal processor starts initialization subroutine and self is carried out initialization, and system is in the preparation state;
(2) user is by interface input operation information such as touch-screens;
(3) call parameters input subroutine, input technology type, technological parameter determine to adopt any one control algolithm in fuzzy control, PID control and the fuzzy control;
(4) start the running of programmable controller controls electric motor system; Described digital signal processor judges by acquired signal whether described governing system is in normal operating conditions, if undesired then described governing system is not worked, motor enters full speed running, in case normally enter speed regulating control at any time;
(5) start interior circular current control, described interior circular current controller output is to the control signal of described boost chopper;
(6) start the outer shroud speed control, control given motor speed by fuzzy control/PID, the control electromotor velocity steadily rises or descends;
(7) phase place of detection of grid produces fixedly the trigger impulse of phase angle by circular current controller in described and controls described thyristor inverter, makes described thyristor inverter feedback electrical power;
(8) described digital signal processor is patrolled and examined described thyristor inverter generation inversion and is overturned, then inside circular current controller output overcurrent signal, interior circular current controller starts inversion stalling protection circuit by logic gates output control signal thyristor inverter is protected, information is overturned in the demonstration inversion, and switches to full speed running by the speed governing state;
(9) described digital signal processor is patrolled and examined described governing system and whether is had overcurrent, overvoltage, overheated, open-phase fault, then can not keep speed governing operation if having; If above-mentioned fault takes place, then described governing system is protected, show dependent failure information, and the speed governing state switches to full speed running;
(10) described digital signal processor is implemented protection control to described electric motor system and environment corollary equipment.
The present invention has the middle voltage electromotor chopper speed governing digital intelligence control system of stalling protection, and wherein said interior circular current controller comprises differential amplifier, D/A converter, down counter, comparator and output trigger; Described governing system is provided with that the pulse code-disc directly tests the speed or rotor current voltage acquisition system tests the speed indirectly, and lime sensor acquisition rotor rectified current, high impedance difference channel are gathered rotor commutating voltage, dc inversion voltage in rotor current voltage acquisition system; In described the 6th step, described digital signal processor provide clock, fuzzy/pid control algorithm is given, the minimum service time of chopper and minimum turn-off time, above-mentioned acquired signal is carried out after the logical operation Current limited Control pulse with the current peak two point form by circular current controller in described, control the switching tube of described boost chopper, duty ratio is regulated in requirement according to speed governing, thereby changes dc inversion voltage.
The present invention has the middle voltage electromotor chopper speed governing digital intelligence control system of stalling protection; wherein said digital signal processor stores input-output subprogram; can realize man-machine interaction by interfaces such as touch-screens, the setting, controller type of carrying out technological parameter selected, the preservation of technological parameter and revise some operations.
The present invention has the middle voltage electromotor chopper speed governing digital intelligence control system of stalling protection; wherein said digital signal processor stores to be handled described governing system overcurrent, overvoltage, overheated, open-phase fault and inversion and overturns fault, and the warning subprogram of described electric motor system and environment corollary equipment fault.
The present invention has the middle voltage electromotor chopper speed governing digital intelligence system of stalling protection; wherein said digital signal processor stores the telemanagement subprogram; by RS232/RS485 communication interface and/or CAN fieldbus and/or the computer-implemented telemanagement of IP interface and Surveillance center, described Surveillance center computer directly carries out remote monitoring to the state of described governing system.
The present invention has the middle voltage electromotor chopper speed governing digital intelligence system of stalling protection, and wherein said digital signal processor replaces with single-chip microcomputer.
Middle voltage electromotor chopper speed governing digital intelligence control system with stalling protection provided by the invention; its beneficial technical effects is: when keeping the existing whole advantages of chopped mode cascade adjustable-speed system; utilize the turn-off capacity of insulated door based transistor; the inversion stalling protection that cut off its direct current main circuit Shi Now when the thyristor inverter inversion is overturned, Xie Jue Now have thyristor inverter that system the exists problem at electrical network Gu Zhang Time damage equipment.Simultaneously, owing to adopt current peak relatively to realize two point form control in the circular current control, replace current regulator and duty ratio D generator in chopper, be not subjected to the boost chopper non-linear effects, error is little, need not to adjust dynamic parameter, and is easy to use.At underloading Dian stream Duan Xu Time, controller endure.Owing to adopt the Fuzzy Logic in Intelligent control technology; the digital Control Technology that digital signal processor DSP combines with interior circular current controller and programmable controller; the digital intelligent degree height of governing system; solved the non-linear problem that maybe can't set up precise control model of electric machine speed regulation well; and have good man computer interface and a means of communication flexibly; can select suitable control algolithm and technological parameter according to technological requirement and field condition; realize the communication of governing system and upper managing computer by RS232/RS485 or CAN fieldbus; or directly connect with the center monitoring computer by built-in IP interface module; carry out remote monitoring and management; by the rich data acquisition interface, speed governing and electric system and blower fan and pump class etc. are carried out on-site supervision and protection.
The present invention is described in detail with reference to accompanying drawing below in conjunction with embodiment.
Embodiment
The present invention has the middle voltage electromotor chopper speed governing digital intelligence system of stalling protection, and with reference to Fig. 1, MD is an electric motor system, comprises motor M and auxiliary devices such as start-up control switch and distribution.Governing system MSR comprises that chopper speed governing main circuit and DSP (or single-chip microcomputer) with stalling protection are main digital intelligent control section.In main circuit, the uncontrollable rectifier DR among the governing system MSR switches through sub-winding (the normal Gong Zuo of Zheng Time K by the brush and the slip ring of motor
1Disconnected liter, K
2Closed), the thyristor inverter TI in the system gets access to grid by transformer TF.BC among the governing system MSR is that boost chopper is (by L
DR, V
1, D
1Form with C), IFP is that inversion stalling protection device is (by V
2And D
2Form), FR is starting frequency sensitive trheostat, K
1And K
2Be three-phase contactor.Digital control part comprises digital signal processor DSP (Digital Signal Processor), interior circular current controller NFC and programmable controller PLC (Programmable Logic Controller), wherein interior circular current controller NFC realizes that it is made up of D/A conversion, comparator C P and on-site programmable gate array FPGA (Field Programmable GateArray).
Since process control technology by the discrete component in past, simple integrated circuit develops into single-chip microcomputer, DSP, on-site programmable gate array FPGA, programmable controller PLC is the Digital Control circuit of core, promptly develop to the digitlization direction.
In the present invention, the structure of FPGA mainly is divided into three parts: configurable logic block CLB (Configurable LogicBlocks), programmable I/O module and interconnector able to programme.FPGA clock frequency height, inner time delay is little; All control logic is finished by hardware, and speed is fast, the efficient height; Composition form is flexible, can integrated peripheral control, decoding and interface circuit.These speed regulating device adopt two closed-loop control, i.e. current inner loop and speed outer shrouds.Wherein current inner loop is to realize recently that by the duty of control chopping switch device V1 it is all higher to the speed and the reliability requirement of control circuit.In addition, opening of inversion stalling protection device V2 and inverter switching device pipe V3 also all requires control circuit that good antijamming capability is arranged.Therefore the low layer control circuit of this governing system selects FPGA circuit at a high speed to be realized.FPGA can adopt the series of products of the leading Xilinx company in this field, as XC3000, XC4000 to Spartan-II E and VirtexII Pro etc., FPGA can couple together logic array according to the field programming that requires of controlled function, and the logic array scale that FPGA comprised can be selected flexibly.
Single-chip microcomputer is Complex Instruction Set Computer (CISC), needs in the computing to take the more instruction cycle, and execution speed is slow, but single-chip microcomputer has very strong external interface ability.Present 16 single-chip microcomputers of development are enhanced on speed as the 80C196KC of Intel.DSP belongs to Reduced Instruction Set Computing (RISC), and most of instructions can both be finished in one-period, and can pass through parallel processing technique, finishes many instructions in an instruction cycle; Simultaneously, DSP adopts improved Harvard structure, has the program and the data/address bus of separation, allows stored program and data simultaneously; Adopt multi-stage pipeline and built-in high-speed hardware multiplier, make it have data operation ability at a high speed, the chip of representative has TMS320LF24x series.In speed regulation process, carry out the given adjusting of speed according to technological parameter, rate integrating computing in electric motor starting and the moderating process, the fault alarm of governing system, electric machine and controlling object blower fan and pump class etc., these occasions are had relatively high expectations to control strategy and control algolithm, so governing system adopts DSP to cooperate software programming technique to realize above-mentioned control.The DSP that governing system is used can select the Motor Control special chip TMS320C24xx of American TI Company or high-end TMS320C28xx, 16 products such as 80C196KC of the optional Intel Company of single-chip microcomputer.
That PLC has is easy, reliable, be easy to advantage such as use, and in governing system, the strict follow procedure of the action need of machinery and electric device cooperates execution, so that control system and PLC are used is very necessary.The major control step of PLC is as follows: (1) speed-adjusting start process.Before the K closure, the K1 and the K2 of former primary state open; Before the K closure, K1 is earlier closed, and K2 opens, K close and and a period of time of delaying time after, motor speed rises to a certain degree K2 closure; Delay time a period of time, motor speed is higher again, and all are normal for governing system, and K1 opens, and governing system puts into operation; If there is abnormality governing system inside in the start-up course, K1 does not open, and governing system does not put into operation, the motor constant-speed operation.(2) governing system is in service when breaking down, the K1 closure, and K2 opens, and motor quickens from low to high; After time-delay a period of time, the K2 closure, motor changes constant-speed operation over to.When (3) stopping in emergency, the K1 closure, K2, K open.
With reference to Fig. 5, in chopper and inversion stalling protection circuit, adopt full controlled tr tube IGBT (Insulated Gate BipolarTransistor) or IGCT (Integrated Gate Commutated Thyristor), IGBT is the insulated door bipolar transistor, IGCT is an integrated gate commutated thyristor, also can adopt other can turn-off power electronic device, as high power transistor GTR etc.; Inverter adopts thyristor SCR.Since carry out the low pressure speed governing in rotor-side, low to the requirement of withstand voltage of switching device, can adopt price to hang down the complete switching device of description.
With reference to Fig. 6, in the present invention, the digital intelligent hardware control system is a double-layer structure, and the upper strata is DSP, and lower floor mainly is made up of FPGA and PLC.DSP mainly finishes the control of outer shroud speed, for circular current control in the FPGA offers value data.Jointly governing system and electric system are directly controlled by FPGA and PLC, wherein FPGA finishes the adjustment of chopper output voltage U D and overturns switching tube for inverter TI and inversion provides trigger impulse, PLC finishes the startup to electric motor system and governing system, and when governing system breaks down, the automatic switchover motor is to the full speed running state, in governing system just often, make motor put into speed governing operation fast again.
With reference to Fig. 7, in interior circular current control, the current peak two point form control of chopper BC, the control of inversion stalling protection pipe IGBT and the generation of inverter TI thyristor start pulse signal select for use a slice FPGA of appropriate scale to realize.Wherein D/A is a digital to analog converter, and CP is a comparator, and MC is a down counter.
The generation of the input/output signal of current peak two point form control: the lime transducer LEM among the rotor current voltage acquisition UIM of system gathers rotor rectified current I
DR, the high impedance difference channel is gathered rotor commutating voltage U
DR, the dc inversion voltage U
DDSP provides clock for FPGA, the fuzzy/given I of pid control algorithm among the DSP
DR *After the current peak two point form processing of circuit of above-mentioned signal by D/A, CP and FPGA composition, obtain the pwm control signal of chopper switches pipe IGBT, and regulate duty ratio, thereby change the dc inversion voltage U according to the requirement of speed governing
DThe minimum service time t of chopper is provided by DSP (or single-chip microcomputer)
OnWith minimum turn-off time t
Off, produce and these two corresponding pulses of time by pulse generator, and carry out exporting the needed Current limited Control pulse of chopper after the logical operation with normal pulse signal.
The trigger impulse of inverter TI thyristor produces: by the phase place of detection of grid, produce fixedly phase angle trigger impulse control thyristor inverter TI by FPGA, make inverter feedback electrical power.
The process of inversion stalling protection: set upper current limit in FPGA, sensed current signal in inverter TI input DC loop is judged and is delivered in the logic gates of FPGA by DSP (or single-chip microcomputer).When overcurrent takes place, send control impuls by FPGA and drive IGBT inversion stalling protection pipe V
2Open-minded, thus thyristor inverter TI is played a protective role, prevent the generation that inversion is overturned.
With reference to Fig. 8 a) and Fig. 8 b), in the oscillogram of current peak two point form control, when rotating speed is low, I
DRThe rate of rise little, and Δ U
cThan higher, U
cThe slope height that descends is like this by I
DRAnd U
cChange procedure in meet and can obtain an intersection point clearly; Opposite rotor voltage U
DRRelatively lower high, I
DRThe rate of rise big, and Δ U
cLower, U
cThe slope that descends is low, like this by I
DRAnd U
cProcess in meet and equally also can obtain an intersection point clearly.So just can guarantee that no matter governing system is to be in low speed and high speed stage can both guarantee that speed regulation process carries out reliably.
With reference to Fig. 9, be controlled to be example with the hydraulic pressure of water pump, the speed regulating control process of motor is described.In two loop control theories of governing system, interior ring is a Current Control, adopts the control of current peak two point form to realize by FPGA, and the speed outer shroud adopts fuzzy control/pid control algorithm to realize by DSP.Wherein, fuzzy control/pid control algorithm is stored among the DSP in advance, comprises FUZZY ALGORITHMS FOR CONTROL, pid algorithm and self-adjusting parameter fuzzy pid control algorithm, and which kind of control algolithm is system adopt according to the technology type and the duty parameter decision of input.The step of water pump hydraulic pressure control procedure is as follows: (1) is detected relatively by the hydraulic pressure of given hydraulic pressure and feedback, and consider parameters such as other technological parameter such as feedwater flow, steam flow, steam water-level, obtain the hydraulic pressure controlled quentity controlled variable by fuzzy logic, and obtain the given rotating speed of motor by fuzzy control/PID controller.(2) electromotor velocity curve RAMP is slope control, changes at motor speed adjusting process medium velocity and adopts the mode that slowly rises and slowly descend, and makes the rate of change di/dt of motor current and voltage and du/dt all not too large.(3) ASR is an automatic speed regulator, by integral element speed regulation process is steadily carried out, and sets upper current limit.(4) ACR is an automatic current regulator, adopts current peak two point form control method.(5) by the switch I GBT of FPGA output PWM control chopper, adjust the size of chopper output current and voltage, thereby realize speed governing.(6) by the phase place of detection of grid, produce the fixedly trigger impulse control thyristor inverter TI of phase angle, make inverter feedback electrical power by FPGA.
With reference to Figure 10, the DSP of governing system possesses communication interface, RS232/RS485 is for to be used to realize the conversion to RS-485 by RS-232 by special industrial control module, can monitor the operation conditions of many governing systems simultaneously by industrial computer, can discern each governing system by address code.Can design an IP interface module with the DSP communication, make this governing system possess direct remote communications capability.Intranet is an enterprises lan, can realize the large-scale communication of enterprises by optical fiber and Ethernet technology, and the state that so just can directly exchange speed system at monitoring system center carries out remote monitoring.
With reference to Figure 11; have among the embodiment of middle voltage electromotor chopper speed governing digital intelligence system of stalling protection in the present invention; implement the interior circular current of IGBT chopper BC is controlled by interior circular current controller NFC; the control of thyristor inverter TI and inversion stalling protection; by the outer shroud speed control of digital signal processor DSP enforcement to governing system; by the program control of programmable controller PLC enforcement to governing system MSR and electric motor system MD; the step of governing system work is described in detail as follows: after the start of (1) governing system powers on; DSP starts initialization subroutine self is carried out initialization, makes control system be in the preparation state.(2) screen displaying is started working, and the user can input operation information.(3) system program is transferred the parameter input subroutine, input technology type, technological parameter etc., and which kind of control algolithm is system adopt by integrated decision-making, as fuzzy control, PID control and fuzzy control.(4) by the entry into service of PLC control electric motor system; DSP judges by the digital signal that the A/D change-over circuit collected analog signal, PLC and obtain and the digital signal of other switching device output whether governing system is in normal operating conditions, if undesired then governing system is not worked, motor enters full speed running, in case normally can enter the speed governing state at any time.(5) after entering the speed governing state, control given motor speed I by fuzzy control/PID
*, steadily rise or descend by electromotor velocity curve RAMP control electromotor velocity.(6) interior circular current control system work, the LEM sensor acquisition rotor current I among the current/voltage acquisition system UIM
DR, the high impedance difference channel is gathered rotor voltage U
DR(or directly test the speed by the pulse code-disc), dc inversion voltage U
D, respectively with I
*With I
DR, U
DRWith U
DCompare, control the PWM of given chopper by current regulator ACR by the peak current two point form.(7) by the phase place of detection of grid, produce trigger impulse control inverter TI, make inverter feedback electrical power by FPGA.(8) DSP patrols and examines governing system, overturns fault if inversion takes place, and starts inversion stalling protection switching tube thyristor inverter is implemented protection, and the speed governing state is switched to full speed running.(9) DSP patrols and examines governing system, and whether the system of seeing exists faults such as overcurrent, overvoltage, overheated and phase shortage, then can not proceed speed governing operation if having; If break down, then governing system is protected, and the speed governing state is switched to full speed running.(10) DSP also can provide protection to electric system and environment corollary equipment.
Have among the embodiment of middle voltage electromotor chopper speed governing digital intelligence control system of stalling protection in the present invention, governing system outer shroud speed control can adopt fuzzy control, PID control and self-adjusting parameter fuzzy PID controller.To be fuzzy control that dynamic response characteristic is good combine with the good PID control of steady-state response characteristic fuzzy controller, can give full play to advantage separately.Utilize Fuzzy parameter optimization technology, to the proportional gain k of PID controller
p, integration time constant k
iWith derivative time constant k
dCarry out online adjustment, thereby realize the Optimal Control of electric machine speed regulation process.With reference to Figure 12 a) and Figure 12 b), be controlled at the example that is applied as on the water pump hydraulic pressure with self-adjusting parameter fuzzy PID, this governing system control principle and software flow have been described.Can import technological parameter and select fuzzy controller by touch-screen; By the given motor speed curve of integrator Ramp, make slow liter of motor speed or slow falling; Measure rotating speed of motor or electric resistance partial pressure detection rotor voltage and infer the actual speed of motor by the pulse code-disc; Relatively give stator and rotor current by speed regulator ASR in the back with given rotating speed and actual speed, record the rotor actual current by the LEM transducer, by relatively drawing the rotor current regulated quantity.Here mainly utilize the parameter of the online adjustment of fuzzy controller PID, can give full play to fuzzy control and PID control advantage separately.
The embodiment that the present invention has the middle voltage electromotor chopper speed governing digital intelligence system of stalling protection has made full use of the powerful internal memory extended capability of DSP, and the fuzzy controller and the parameter of passing through the relevant controlled device of technological experiment acquisition is stored in the ROM program area.As to blower fan, pump class etc. by the research that experimentizes of different size capacity, can obtain fuzzy controller and parameter under the different technology conditions, can select suitable controller and parameter according to the Be Controlled object in the control at the scene, make system can enter running status more stably at the very start.
With reference to Figure 13, in the parameter input-output subprogram of this governing system, can realize man-machine interaction by touch-screen, carry out the operations such as setting, selection control type, preservation and modification technological parameter of technological parameter.
With reference to Figure 14, in the troubleshooting and warning subprogram of this governing system, the overcurrent of governing system, overvoltage, overheated, phase shortage and inversion are overturned etc. the fault of fault and motor and auxiliary system and handle, and demonstrate warning message.
Have among other embodiment of middle voltage electromotor chopper speed governing digital intelligence system of stalling protection in the present invention, wherein digital signal processor DSP can replace with single-chip microcomputer.
The embodiment that the present invention is had a middle voltage electromotor chopper speed governing digital intelligence system of stalling protection is described in further details below.
Be suitable for the present invention and with the drive motor of governing system four classes arranged: middle pressure conventional wound asynchronous motor, middle pressure internal feedback wire wound asynchronous motor, middle pressure are around cage brushless double-fed motor and middle pressure cage internal feedback motor.
Embodiment 1:
With reference to Fig. 1, in the present embodiment, motor M is middle pressure conventional wound asynchronous motor.Need a peripheral hardware transformer TF for connecting inverter TI and medium voltage network.
Uncontrollable rectifier DR in the governing system switches through sub-winding (the normal Gong Zuo of Zheng Time K by the brush and the slip ring of motor
1Disconnected liter, K
2Closed), the thyristor inverter TI in the system gets access to grid by transformer TF.BC in the governing system is a boost chopper, and IFP is an inversion stalling protection device, and FR is starting frequency sensitive trheostat, K
1And K
2Be three-phase contactor.
Cascade adjustable-speed system is connected on rotor side, rotor voltage
U
R=sU
R0
In the formula: s=(n
0-n)/n
0----slippage; U
R0For motor does not change, the rotor voltage of s=1 Time.
Piezoelectricity machine U in existing
R0<1000V is when speed adjustable range is restricted to 50% (s≤0.5) Time, U
Rmax≤ 500V is so governing system is a low pressure.
The cascade adjustable-speed system main circuit is in the circuit of cover uncontrollable rectifier DR, a boost chopper BC, inversion stalling protection device IFP and thyristor inverter TI composition, as the normal Gong Zuo of the Zheng of system Time insulated door based transistor V
2Conducting does not always influence inverter TI work.Work as electric network fault, U
AwReduce too much or Xiao Shi Time, inversion takes place overturn thyristor inverter TI output current I
AwGreater than the overcurrent set point, insulated door based transistor V
2Turn-off, thyristor inverter TI quits work, and originally the electric current in the inversion circuit inductance is through diode D
2Afterflow reduces to zero gradually, and the high voltage of avoiding inducting damages the insulated door based transistor.Inversion is overturned Xin Tong Time and is delivered to contactor K
1And K
2Control circuit, make K
1Closure, short circuit rectifier DR input, motor changes constant speed work automatically over to.
The normal Gong Zuo of Zheng Time, governing system of the present invention is the same with existing chopped mode cascade adjustable-speed system, and it is constant that the triggering phase shift advance angle β of thyristor inverter TI is fixed on minimum value (about 30 °), and dc inversion voltage is fixed (U
DThe ≈ constant), change rotor voltage U after uncontrollable rectifier DR rectification by the duty ratio D that changes boost chopper BC
DR
U
DR=(1-D)U
D
Realize speed governing.Thyristor inverter TI and transformer TF capacity P
TIAnd P
TFBy the maximum rotor power output
Choose, for blower fan and the load of pump class quadratic form, I
R∝ n
2, rotation speed n Gao Time, I
RGreatly, U
RLittle, P
RNot quite; Rotation speed n Di Time, I
RLittle, U
RGreatly, P
RAlso little; Maximum P
RAppear at n=(2/3) n
0(s=1/3) time, P
Rmax=0.1 5P
N, consider that load is not strict quadratic form relation, stay certain abundant putting, get P
TI=P
TF=(0.2~0.3) P
N, with (0.2~0.3) P
NThe low pressure inverter of power and transformer control 100%P
NThe middle piezoelectricity machine speed governing of power.Because thyristor inverter power is little, and the β angle is fixed on 30 °, and it is idle little that inverter produces, and the governing system total power factor improves many than traditional cascade adjustable-speed system, and the harmonic wave that brings to electrical network is also little.
In realizing speed closed loop control, the control of boost chopper is by speed outer shroud and electric current I
DRInterior ring two parts constitute.Because at different rotating speeds (different U
DR) under, the duty ratio D of boost chopper and dc inversion voltage U
DBetween relation be non-linear, usually, adopt current regulator to realize current inner loop control, cause the current response difference of the fast Time of different commentaries on classics, regulator parameter is adjusted difficult.If adopt the current hysteresis ring bang-bang controller realizes current inner loop control, can overcome non-linear effects, but the chopper switches frequency will change with rotation speed change, and underloading Dian stream Duan Xu Time bang-bang controller cisco unity malfunction.In an embodiment of the present invention, then adopt a kind of new Dian Liu Mine value two point form controller to realize electric current I
DRInterior ring control, it both can overcome the non-linear effects of boost chopper, need not to adjust dynamic parameter, and switching frequency is fixed, and Dian stream Duan Xu Time also can work.
With reference to Fig. 7 and Fig. 8, control in the oscillogram of k switch periods at the current peak two point form, each switch periods Kai Shi Time carves, and the triggering input S of R-S trigger FF receives a pulse signal, and R-S trigger FF output Q exports high level, copped wave pipe V
1Conducting, rectified current I
DRIncrease it and control voltage U
CIn comparator C P, compare,
U
c=I
*+ΔU
c
In the formula: U
DRAnd U
DBe respectively commutating voltage and dc inversion voltage
L
DRIt is rectifying and wave-filtering inductance value (containing the motor leakage inductance)
I
*It is the electric current set-point
T is a switch periods
τ is Zhong the k switch periods between De Time, as t=kT Time, and τ=0; As t=(k+1) T Time, τ=T.
Work as I
DRIncrease to I
DR=U
cTime, comparator C P exports high level, delivers to the RESET input R of R-S trigger FF, and R-S trigger FF resets, copped wave pipe V
1Turn-off, finish until this switch periods.By this method control, electric current I in a switch periods
DRMean value equal electric current set-point I
*
With reference to Fig. 7, voltage differential signal U
D-U
DRFrom differential amplifier DA.Time clock signal clock delivers to down counter MC, and then the number in counter is 1-τ/T.After the number among the MC reduced to zero, its carry end sent a carry signal, and with its triggering input signal st as R-S trigger FF, MC Tong Time is back to full position, prepares the counting of the next switch periods of beginning.Number among the down counter MC and voltage difference analog signal U
D-U
DRMultiply each other in the D/A converter, D/A exports through the potentiometer dividing potential drop, if the dividing potential drop coefficient is T/2L
DR, then potentiometer is output as signal delta U
cΔ U
cWith the given signal I of electric current
*Addition gets control signal U
c, with U
cDeliver to comparator C P
1With current signal I
DRRelatively, comparator C P output reseting input signal rst to R-S trigger FF.
Embodiment 2:
With reference to Fig. 2, in the present embodiment, motor M is middle pressure internal feedback wire wound asynchronous motor.The additional winding of one cover three-phase is arranged, output 50Hz fixed voltage U in the internal feedback wire wound asynchronous motor stator
Aw,, accept the feedback electric current I for inverter usefulness
Aw, do not need peripheral hardware inverter transformer.Its governing system is identical with accompanying drawing 1, and uncontrollable rectifier DR switches through sub-winding by the brush and the slip ring of motor, but thyristor inverter TI connects the auxiliary winding in the motor stator, no-reverse change power transformer TF.
Embodiment 3:
With reference to Fig. 3, in the present embodiment, motor M is that middle pressure is around the cage brushless double-fed motor.The rotor winding of this motor is not drawn, brushless and slip ring, and two cover stator winding, a cover gets access to grid, and another set of function is equivalent to coiling electric motor rotor winding, meets the uncontrollable rectifier DR of governing system.Governing system is identical with Fig. 1, and thyristor inverter TI gets access to grid by transformer TF.
Embodiment 4:
With reference to Fig. 4, in the present embodiment, motor M is middle pressure cage internal feedback motor.The rotor winding of this motor is not drawn, and brushless and slip ring, stator are provided with internal feedback winding winding, two cover stator winding are arranged, draw the slip power of motor from a cover winding wherein, be rectified into direct current through the uncontrollable rectifier DR of governing system, inverter INV becomes to exchange and is connected with electrical network.Its governing system is identical with embodiment 1.
Middle voltage electromotor chopper speed governing digital intelligence control system with stalling protection provided by the invention has the following advantages:
1) means of communication flexibly: give full play to the numerically controlled ability to communicate of DSP, carry out communication, or built-in IP interface is realized telecommunication by its RS-232/RS485 serial port and upper management computer.In the communication that utilizes the RS232/RS-485 bus to carry out, a upper industrial computer IPC can carry out communication with many governing systems simultaneously, industrial computer IPC can realize telecommunication by intranet Intranet, thereby the state information at speed governing scene is passed to Surveillance center.In addition, consider the rapid enforcement at home and abroad of Ipv6 technology, this governing system has also designed the IP interface module, module adopts the universal industrial Ethernet chip, make the built-in IP function of module by Java embedded programming technology, thereby can make this governing system directly carry out telecommunication by Intranet.So just can carry out remote control, remote signalling, remote measurement to this governing system, unattended operation can directly monitor the running status of this governing system in Surveillance center.
2) good man computer interface: because DSP has user-machine interface flexibly, can carry out the parameter input and output by touch-screen etc. and show, as: the input technological parameter, select fuzzy Control and parameter, revise technological parameter, preserve result selected and that revise; Running status is replied, as starting, move and the arrival set-point; The dynamic demonstration of parametric plot in service is reported to the police and error message shows; The inquiry of governing system and motor data.
Various faults such as 3) perfect defencive function: in the governing system running, may run into load changing, it is too low motor speed to occur, and inverter output phase shortage, short circuit and inversion are overturned, and have a power failure suddenly, and the inverter heating is serious.After in this governing system, using the DSP Digital Control, can make full use of its powerful signals collecting and abundant digital I/O mouth, governing system and electric system are comprehensively monitored and protected.Adopting DSP also can make full use of its CAN fieldbus comes field apparatus to monitor.In the design of the failure diagnosis of DSP, by the running status of timing cruising inspection system monitor the overcurrent, overvoltage of inverter in real time, overheated and inversion is overturned, and motor ventilation, lubricates ambient condition etc.When governing system broke down, DSP called corresponding troubleshooting subprogram, and transferred display subroutine to provide fault message.
The invention has the beneficial effects as follows:
A. the whole advantages that kept existing chopped mode cascade adjustable-speed system:
● with piezoelectricity machine rotating speed in the control of low pressure governing system.
● inverter TI and transformer TF capacity are little, and for the quadratic form load of blower fan and pump class, they only are 20%~30% of motor power (output).
● because brilliant lock inverter power is little, and the β angle is fixed on 30 °, and it is idle little that inverter produces, and the governing system total power factor improves many than traditional cascade adjustable-speed system, and the harmonic wave that brings to electrical network is also little.
B. set up inversion stalling protection device, the thyristor inverter that Xie Jue Now has system to exist is overturned the damage equipment problem in electrical network Gu Zhang Time inversion.
C. new current peak two point form controller is adopted in circular current control in the chopper, is characterized in:
● realize two point form control with the electric current peakedness ratio, replace current regulator and duty ratio D generator, be not subjected to the boost chopper non-linear effects, need not to adjust dynamic parameter, easy to use.
● electric current I in a switch periods
DRMean value equal electric current set-point I
*
● in the underloading electric current I
DRWhen interrupted, the controller endure.
● with zigzag control signal U
cAnd I
DRRelatively, all intersection point is clear and definite in whole ranges of speeds, and error is little.
D. adopt the Fuzzy Logic in Intelligent control technology, and the digitizing technique that combines with FPGA, PLC of DSP, its outstanding feature is:
● built-in Fuzzy Logic in Intelligent control algolithm can solve the non-linear problem that maybe can't set up precise control model of electric machine speed regulation well;
● have good man computer interface, can select suitable control algolithm and technological parameter according to technological requirement and field condition;
● means of communication flexibly, the communication of governing system and upper managing computer be can realize by RS232/RS485, or directly remote monitoring and management connected with the center monitoring computer by built-in IP interface module;
● perfect defencive function, can pass through the rich data acquisition interface, speed governing and electric system and blower fan and pump class etc. are carried out on-site supervision and protection.