CN100464492C

CN100464492C - Constant current driver for step motor

Info

Publication number: CN100464492C
Application number: CNB031243983A
Authority: CN
Inventors: 何伟斌
Original assignee: 何伟斌
Current assignee: Dalian Tianyuan Electrical Machinery Co., Ltd.
Priority date: 2003-05-07
Filing date: 2003-05-07
Publication date: 2009-02-25
Anticipated expiration: 2023-05-07
Also published as: CN1484373A

Abstract

A step machine constant current driver includes chopper drive circuits and a controller among which the chapper drive circuits contain multiple same independent drive circuits having the same phase with the machine provided by independent power source and each connecting to a phase winding, the phase winding ends are mutually connected, no current-limiting resistor is set with the hopper circuit. The said controller uses a time delay circuit to regalate rate of output pulse so as to suit the input pulse rate to output pulse.

Description

The stepping motor constant-flow driver

Technical field

The present invention relates to driving source for step motor, particularly, the three-phase and four-line stepper motor driver of numerically controlled wire cutting machine.

Background technology

In the prior art, numerically controlled wire cutting machine is extensive use of stepping motor, particularly the three-phase and four-line stepping motor is as controlled driving power, adopt current-limiting resistance in its drive circuit, when its supply power voltage is 24V, when phase current was 2-3A, there was waste of electric energy in every power consumption that 48W-70W is arranged approximately when working mutually on this current-limiting resistance.Secondly, come its pulse period of signal of self-controller to alter a great deal, in order to improve control precision, the assurance stepping motor is not lost the step, and drive circuit will provide enough power headroom and limit running frequency at reduced levels, thereby makes motor torque very little.Moreover, in the constant current chopper circuit of prior art, each phase winding of stepping motor can not be connected into has common port, gives the repacking of wire cutting machine tool driving power like this and upgrade to involve the whole winding joints of motor, thereby make troubles, be not suitable for using the three-phase four-wire system stepping motor.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of stepping motor constant-flow driver, its drive circuit overcomes being not suitable for the three-phase four-wire system stepping motor, having bigger waste of energy, running frequency to be limited in shortcomings such as reduced levels, torque be little of existing in the prior art, each is by independently copped wave drive circuit driving, by independently power supply power supply, its controller output pulse period is done gradually long or gradually short the variation according to the cycle of input pulse.

For reaching above purpose, technical scheme of the present invention is:

A kind of stepping motor constant-flow driver comprises copped wave drive circuit and power supply; Described copped wave drive circuit provides the constant current chopper electric current for the stepping motor phase winding, comprises power amplifier and current detecting and control circuit; It is characterized in that having a plurality of identical described copped wave drive circuits, the number of phases of its number and stepping motor is consistent, each drive circuit is by the independently power supply power supply mutually of same number, each phase winding of stepping motor inserts in the power amplifier of a described drive circuit, and another termination of each winding of stepping motor is connected to each other together.

A kind of stepper motor driver according to a further aspect in the invention comprises drive circuit and power supply, it is characterized in that comprising controller CPU, and its signal input part is connected with pulse signal source, and output is connected with drive circuit; Described controller comprises counter, timer, and described counter is counted according to the forward and reverse rotation of input pulse; Described timer is in CPU inside, and it provides many grades of delay time constants, and CPU increases, subtracts the delay time constant step by step according to the counting of above-mentioned counter in the break in service work of timer, regulating impulse output.

Effect of the present invention is that constant current chopper drives the three-phase and four-line stepping motor, makes the rotation of stepping motor level and smooth, and driving moment is big, and the assurance stepping motor is not lost the step, improves the power utilization rate, improves control rate.

Description of drawings

Fig. 1 is the circuit diagram of the embodiment of the invention.

Fig. 2 is the master control workflow diagram of embodiment of the invention middle controller.

Fig. 3 is interruption, the services flow chart of embodiment of the invention middle controller.

Embodiment

Describe embodiment in detail below with reference to accompanying drawing.

Fig. 1 is driver embodiment physical circuit figure of the present invention.Driver drives three-phase and four-line reaction stepping motor in this example, drive circuit comprise three independently identical voltage source UA, UB, UC of waiting, and give three separate constant current chopper drive circuitry.These three groups of power supplys are not established common junction, export about 24V.LA, LB, LC are three groups of phase windings of stepping motor, because chopper circuit is independent mutually, do not have the tie point of electricity, so stepping motor can have common junction O, are applicable to the three-phase four-wire system stepping motor.

Be the work of example explanation copped wave drive circuit with control step motor A phase winding LA below: the copped wave drive circuit comprises the current detecting and the control circuit of power amplifier, control circuit, power amplifier is connected in series by second switch pipe QA2, stepping motor one phase winding LA, the first switching tube QA1 and current sampling resistor RA1 and forms the leakage resistance of not limiting.And current detecting and control circuit comprise: make voltage ratio by the Shi Mite circuit that operational amplifier ICA2 and RA9 form, and make current detecting and output control signal, ICA1 is an AND circuit, and QA3 is the prestage of second switch pipe.The concrete course of work is as follows:

The first switching tube QA1 can manage with Darlington transistor or VMOS, second switch pipe QA2 is the Darlington transistor of PNP, DA2 is a fly-wheel diode, the electric energy that DA1 discharges coil when QA1 closes reclaims to the power supply discharge, RA1 is a current sampling resistor, RAW is the current settings potentiometer, and ICA2 and resistance R A9 constitute the Shi Mite circuit.When photocoupler OA1 no signal, its receiving tube is an open-circuit condition, and switching tube QA1 does not have forward bias and closes, with the P2 pin of door ic chip A1 be low level, the P3 pin is output as low level, QA3 is operated in cut-off region, QA2 also is operated in cut-off region.Therefore there is not electric current among the coil LA.When OA1 had input, its receiving tube was a conducting state, and the P2 pin of ICA1 is a high level, and switching tube QA1 obtains forward bias current, the QA1 conducting.During the firm conducting of QA1, sample resistance RA1 voltage is 0V, and the integrated P3 pin of operational amplifier ICA2 has been connected to setting voltage, the P3 pin is higher than P2 pin level, P1 pin output high level, and promptly the P1 pin of ICA1 is high, the P2 pin has been high, thereby P3 pin output high level, and QA3 obtains positive bias and conducting, QA2 is conducting also, the LA coil current rises, and the last electric current of RA1 rises, simultaneously, the P2 pin current potential of integrated ICA2 rises, when P2 pin current potential is higher than the P3 pin, the upset of Shi Mite circuit, P1 pin output low level, P3 pin output low level with door ICA1 integrated package, QA3 ends, and QA2 also ends, after ending, the magnetic energy that has had among the motor coil L A passes through DA2, LA and QA1 continue discharge and afterflow, electric current begins to descend, and the sampling current potential descends, and promptly ICA2 integrated package P2 pin current potential descends, when being lower than P3 pin current potential, the upset of Shi Mite circuit, the QA2 conducting, power supply is powered to LA again, go round and begin again, finish the process that constant current chopper drives like this.When OA1 did not have input signal, QA1, QA2 closed, and the magnetic energy in the coil reclaims to the power supply discharge by DA2 and DA1.The LA winding drive circuit has independent current source, input signal is isolated, thereby does not have common junction with LB winding drive circuit and LC winding drive circuit, isolates mutually, therefore three-circuit get each winding an end as the common junction end, the work of entire circuit is not influenced.

The work of description control device now.

Three-phase signal A, the B of clock, C import CPU, its pulse period of this signal is changeable, in CPU, establish tape symbol counter D counting is given in this pulse, and open timer at CPU, timer is established many grades of delay time constants, and delay time is established 16 grades from long to short in this example, the time constant pointer gets 0-15, and the delay time constant is got between 0.02S-0.7MS.The main program intercourse is according to the selected delay time constant of the value of counter D, the pulse of output three-phase six-beat, unison counter D reverse count.When counter D absolute value equals pointer value, pointer is constant, and selected time constant is constant.When the counting absolute value of pointer value greater than counter D, pointer value is subtracted 1, increase time constant and slow down output speed, otherwise, when pointer value during, pointer value is added 1 less than the counting absolute value, reduce time constant and accelerate output.Like this, stepping motor is 50-1428HZ with operating frequency, gradually quickens step by step or decrescence speed rotation with the speed of input pulse, and stability of rotation is not lost the step.

The workflow of controller is seen Fig. 2,3.Fig. 2 represents CPU main program control flow, and Fig. 3 represents that its timer interrupts, the service routine flow process.

Referring to Fig. 2, CPU judges whether to exist A, B, C signal (S1), whether has turn signal (S2), judges its forward and backward (S3), when just changeing, and pulse of every input, counter adds 1, and starts timer, and jumps to the S1 program of carrying out.During counter-rotating, counter subtracts 1 and start timer, and jumps to the S1 program of carrying out.

Interrupt, service routine be the CPU timer then, interrupt main program, outage, service routine, its course of work flow chart is seen Fig. 3.At first CPU judges that when the count value of counter D is zero (S10), expression does not have input pulse, and program is returned main program.Otherwise relatively there are three kinds of situations in the pointer of time-delay setting and the absolute value (S20) of count value, when equating, pointer is constant, and pointer value hour should be accelerated output, and pointer adds 1 (S201), when pointer value was big, then opposite, pointer subtracted 1, with the output speed that slows down (S202).Subsequently by the selected delay time constant (S30) of pointer value, CPU judges the positive and negative of count value, promptly judges to turn to positive and negative (S40), when count value is that one of timing output is rotated in the forward pulse signal, the count value of counter D is subtracted 1 (S41), return main program then.After judgement turns to when negative, export an anti-rotational pulse signal, on its negative counting, add 1 (S42), return main program then.

At any time follow the tracks of input signal with suitable speed through output pulse after the above process, stepping motor guarantees machining accuracy with gradually acceleration or decrescence speed ground steady operation step by step.

The action of button K1, K2 detects by CPU, and is effective when no A, B, C pulse input, this moment, turn signal was gradually quickened in output, for example: from 500HZ to 10000HZ along or contrary (just or instead) three-phase six-beat signal, change the fast moving work top soon for stepping motor.

Claims

1. a stepper motor driver comprises copped wave drive circuit and power supply; Described copped wave drive circuit provides the constant current chopper electric current for the stepping motor phase winding, comprises power amplifier and current detecting and control circuit; It is characterized in that having a plurality of identical described copped wave drive circuits, the number of phases of its number and stepping motor is consistent, each drive circuit is by the independently power supply power supply mutually of same number, each phase winding of stepping motor inserts in the power amplifier of a described drive circuit, and another termination of each winding of stepping motor is connected to each other together.

2. driver according to claim 1 is characterized in that: described stepping motor is a phase reaction formula stepping motor, and lead-out wire is a three-phase and four-line.

3. driver according to claim 1 and 2 is characterized in that: the power amplifier in the described copped wave drive circuit is by first (QA1) and second (QA2) switching tube, and sample resistance (RA1) and a phase winding (LA) polyphone are formed.

4. driver according to claim 1 and 2, it is characterized in that described current detecting and control circuit comprise: made voltage comparator, reached AND circuit by the Shi Mite circuit that operational amplifier constitutes, two inputs of described voltage comparator are imported the sampling voltage of expression winding current and the voltage that presets that current value is set in expression respectively.

5. driver according to claim 3, it is characterized in that described current detecting and control circuit comprise: made voltage comparator, reached AND circuit by the Shi Mite circuit that operational amplifier constitutes, two inputs of described voltage comparator are imported the sampling voltage of expression winding current and the voltage that presets that current value is set in expression respectively.

6. a stepper motor driver comprises drive circuit and power supply, it is characterized in that also comprising controller CPU, and its signal input part is connected with pulse signal source, and output is connected with drive circuit; Described controller comprises counter, timer, and described counter is counted according to the forward and reverse rotation of input pulse; Described timer is in CPU inside, and it provides many grades of delay time constants, and CPU increases, subtracts the delay time constant step by step according to the counting of above-mentioned counter in the break in service work of timer, regulating impulse output.

7. driver according to claim 6, it is characterized in that described many grades of delay time constants arrange from long to short, and give corresponding pointer value, the count value of described counter is corresponding to the pulse difference of input and output, the absolute value of the count value of more described pointer value of CPU and counter when the absolute value of the count value of counter during greater than described pointer value, increases described pointer value, when the absolute value of the count value of counter during, reduce described pointer value less than described pointer value.