CN205681357U - A kind of novel stepper motor drive system - Google Patents

Abstract

The utility model discloses a kind of novel stepper motor drive system, including host computer, DSP control chip, D/A change-over circuit, motor drive module, power circuit and stepper motor, motor drive module includes power driving circuit.Host computer is for sending instruction to DSP control chip, D/A change-over circuit is for being converted to analog quantity by the digital quantity of the Design of Stepper Motor Subdivision value from DSP control chip, and this analog quantity is sent into power driving circuit, motor drive module rotates according to the signal controling stepping motor of DSP control chip, and power circuit is for providing operating voltage to DSP control chip.The Multi-level microstep system that the utility model uses not only increases the precision of stepper motor, solve low-frequency oscillation, degradation problem under high speed torque, and it has the advantages such as low cost, volume is little, response is fast, use is safe compared with the drive system that traditional single-chip microcomputer, FPGA control chip control, and can well adapt to the demand of various occasion.

Description

A kind of novel stepper motor drive system

Technical field

The utility model relates to motor-drive technique field, is specifically related to a kind of novel stepper motor drive system.

Background technology

With developing rapidly of digital technology and electronic computer, the application of stepper motor is more and more extensive.Accordingly, walk The shortcoming entering motor is also more and more obvious, although stepper motor is without cumulative errors, but the step angle of stepper motor is relatively big and solid Fixed constant so that it is there is step resolution relatively low, low frequency easily vibrates, frequency characteristic difference, other micro machines of noise ratio are big, flexibility Poor, the shortcoming such as physical unit fatiguability.Stepper motor is different from traditional AC and DC motor, it must with special purpose driver, Dc source composition system can be properly functioning.So the performance of stepper motor is heavily dependent on the excellent of its drive system Bad, the quality of drive system is mainly relevant with type of drive.Still have many users to continue to use on domestic market abroad to be washed in a pan The type of drive that the univoltage string resistance eliminated etc. fall behind, the discrete component using in drive circuit is in the majority, poor reliability, and respectively The actuation techniques specification of producer, industrial grade, production technology are uneven.

Traditional type of drive has high-low pressure driving, univoltage driving, chopped mode constant current driving and frequency modulation and voltage modulation to drive, high Low-voltage driving mode can not solve low-frequency resonance phenomenon, and univoltage drive efficiency is low, and chopped mode constant current driving and frequency modulation and voltage modulation drive Dynamic circuit is all excessively complicated.By the analysis to several conventional ADS driving modes above, it is known that traditional type of drive Under, motor running stability difference, vibration and noise easily occur, most importantly resolution ratio is low, it is impossible to meet some high performance Control.

During motor control, the selection of control chip generally has following two scheme: the first chooses special Stepper motor motion-control module, this module has quick advantage easy to use, but its shortcoming is that cost is higher, Er Qiezhuan Decrease the scope of application of controller by module, affect the widespread adoption of product.The control chip that first scheme selects is then Outside being 8 single-chip microcomputers, from unlike the first scheme, program cost is low, but it does not match with motor control (if such as A/D conversion equipment, the PWM passage etc. with more than three tunnels), and Motor Control bothers very much, for meeting fortune at a high speed The requirement calculated uses sophisticated vocabulary so that the arithmetic speed of system is relatively low.

Content of the invention

For solving the problems referred to above, the utility model provides a kind of novel stepper motor drive system, this drive system energy Enough realizing stepper motor even running, running precision is high, solves stepper motor low-frequency oscillation, mistake present in prior art Torque drop problem when step, high-speed cruising.

To achieve these goals, the technical solution adopted in the utility model is: a kind of novel stepper motor drive system, Including host computer, DSP control chip, D/A change-over circuit, motor drive module, power circuit and stepper motor, described motor drives Dynamic model block includes power driving circuit；

Described host computer is bi-directionally connected with DSP control chip, and the output of described power circuit is defeated with DSP control chip Entering end to connect, the output of described DSP control chip connects motor drive module and the input of D/A change-over circuit, institute respectively The output stating D/A change-over circuit connects the input of power driving circuit in motor drive module, described motor drive module Output connect stepper motor input；

Described host computer is for sending instruction to DSP control chip, and described D/A change-over circuit is used for will be from DSP control The digital quantity of the Design of Stepper Motor Subdivision value of chip is converted to analog quantity, and this analog quantity is sent into power driving circuit, described electricity Machine drives module to rotate according to the signal controling stepping motor of DSP control chip, and described power circuit is for DSP control chip Operating voltage is provided.

Described motor drive module also includes logic synthesis circuit, for by task manager EVA life in DSP control chip The phase sequential signal of the two-way becoming PWM ripple complementary respectively and stepper motor carries out logic synthesis, described logic synthesis circuit defeated Entering end and connecting the output of DSP control chip, its output is by the input phase of photoelectric isolating circuit and power driving circuit Even.

Described logic synthesis circuit includes logic gate device 74HC08.

Also include tachometer circuit, be used for testing the speed of stepper motor and turn to, and test result is shown by host computer Illustrating, the input of described tachometer circuit connects the output of stepper motor, and its output connects the input of DSP control chip End.

Described tachometer circuit includes the photoelectric encoder of a two-phase.

Described photoelectric encoder model is E6A2-CW3C.

Also include over-current detection circuit, be used for preventing stepper motor fault from burning, the input of described over-current detection circuit Connecting stepper motor, its output connects DSP control chipPin.

Described power circuit includes two voltage conversion chip connected, for supply voltage conversion is controlled core to DSP Operating voltage needed for piece.

The model of described DSP control chip is TMS320F2812, and described power driving circuit includes that L298N bridge of enjoying a double blessing drives Dynamic chip.

Compared with prior art, the utility model at least has the advantages that.

The utility model sends instruction by host computer to DSP control chip, and will be from DSP by D/A change-over circuit The digital quantity of the Design of Stepper Motor Subdivision value of control chip is converted to analog quantity, is turned according to DSP control chip by motor drive module The analog quantity Driving Stepping Motor of the instruction changed and the conversion of D/A change-over circuit rotates, thus realizes the driving to stepper motor. The Multi-level microstep system that the utility model uses not only increases the precision of stepper motor, solves low-frequency oscillation, high speed torque Lower degradation problem, and it has low cost, volume compared with the drive system that traditional single-chip microcomputer, FPGA control chip control The advantages such as little, response is fast, use safety, can well adapt to the demand of various occasion.

Further, the utility model passes through logic circuit by the comparing unit of task manager EVA in DSP control chip The phase sequential signal of the two-way generating PWM ripple complementary respectively and stepper motor carries out logic synthesis, uses proprietary logic gate device 74HC08 realizes logic synthesis, and such circuit design is relatively simple, is easier to realize.74HC08 is 4 inputs and gate device, by two-way The phase sequential signal phase of respectively complementary PWM ripple and control stepper motor with after, generate the phase sequential signal with copped wave.After chopped Phase sequential signal be input to power driving circuit, the break-make of control switching tube, use the phase sequential signal after copped wave be possible to prevent because of The motor oscillating causing for energy accumulating.Furthermore, by PWM ripple and 4 tunnel phase sequential signal phases with after, by changing accounting for of PWM ripple Empty ratio, equivalence generates staircase waveform form (i.e. dutycycle different staircase waveform), such that it is able to changed flexibly by DSP control chip Become the on off operating mode of each phase winding of stepper motor.

Further, because the PWM ripple of DSP control chip output is data signal, its frequency is very high, but voltage and electricity Flowing very low, its driving force is relatively low, and it also requires level conversion, it is impossible to directly drive the driving core in power driving circuit Piece, otherwise has interference, it is impossible to work normally, thus need to carry out DSP control chip and power driving circuit photoelectricity every From, thus avoid that (i.e. the PWM ripple of DSP control chip output and be input to the PWM ripple of driving chip, side is DSP control because of both sides Coremaking piece, side is drive circuit) the signal potential problem not mating and driving chip cannot be driven, it is thus also avoided that unlike signal Between crosstalk, it is ensured that whole stability of control system.

Further, the utility model is connected current foldback circuit between stepper motor with DSP control chip, to prevent Stepper motor fault is burnt, and when current foldback circuit detects that stepper motor winding current is too high, comparator (LM358) exports High level, is input to DSP control chip through NAND gatePin, processor will block all of comparison and deposit Device so that PWM output channel is all converted to high-impedance state, motor quits work so that system is well protected, thus protects Protect stepper motor.

Further, the utility model use 2000 series DSP control chip TMS320F2812, this chip be for The motion control of motor and design, have that On-Chip peripheral resource is many, built-in motor control special hardware circuit, control function The advantages such as software implementation realizes and equipment is simple and convenient.

Brief description

Fig. 1 is theory diagram of the present utility model；

Fig. 2 is TMS320F2812 power circuit；

Fig. 3 is that DSP control chip is connected figure with 74HC08；

Fig. 4 is the structural representation of optical coupling isolation circuit；

Fig. 5 is the connection circuit diagram of DAC0832；

Fig. 6 is power driving circuit；

Fig. 7 is over-current detection circuit.

Detailed description of the invention

For being better understood from the utility model, make to retouch in detail further to the utility model with embodiment below in conjunction with the accompanying drawings State.

As it is shown in figure 1, a kind of novel stepper motor drive system, including host computer the 1st, DSP control chip the 2nd, D/A conversion electricity Road the 9th, motor drive module, power circuit the 10th, over-current detection circuit the 7th, photoelectric encoder 8 and stepper motor 6, wherein motor drives Module includes logic synthesis circuit the 3rd, photoelectric isolating circuit 4 and the power driving circuit 5 being sequentially connected with, and tachometer circuit includes two-phase Photoelectric encoder 8.

Stepper motor 6 is powered by dc source 11, and host computer 1 is bi-directionally connected with DSP control chip 2, power circuit 10 Output is connected with the input of DSP control chip 2, and the output of DSP control chip 2 connects logic synthesis circuit and D/ respectively The input of A change-over circuit 9, the output of D/A change-over circuit 9 connects power driving circuit 5 input, power driving circuit 5 Output connect the input of stepper motor 6, the input of photoelectric encoder 8 connects the output of stepper motor 6, its output End connects the input of DSP control chip 2, and the input of over-current detection circuit 7 connects stepper motor 6, and its output connects DSP The input of control chip 2.

DSP control chip 2 selects TMS320F2812DSP control chip, and E6A2-CW3C selected by the photoelectric encoder 8 of two-phase Encoder, logic synthesis circuit 3 selects 74HC08 logic gate device, and photoelectric isolating circuit 4 selects HCPL-0631 high speed photo coupling, Power driving circuit 5 selects L298N to enjoy a double blessing bridge driving chip, and D/A change-over circuit 9 selects DAC0832 chip, over-current detection circuit 7 selection LM358 dual operational amplifiers, power circuit 10 selects the power supply electricity of two AMS1117 series to change chip.

The present embodiment uses 2000 series DSP control chips, and this chip is to design for the motion control of motor , have that On-Chip peripheral resource is many, built-in motor control special hardware circuit, control functional software realization and equipment simple The advantages such as convenience.

Host computer 1 provides a personal-machine interface, sends instruction to DSP control chip 2 and shows the work shape of stepper motor 6 Condition.The photoelectric encoder 8 of two-phase exportable two group pulse signals when rotating, are used for testing the speed of stepper motor 6 and turn to, and Shown by host computer 1.

General DSP control chip 2 all uses multiple feed because the core voltage of DSP control chip 2 be 1.8V or 1.9V, and I/O port voltage is 3.3V, and usual supply voltage is all the 5V power supply of standard, the therefore power supply electricity in the present embodiment Road 10 needs voltage conversion chip to carry out step-down voltage stabilizing, as in figure 2 it is shown, AMS1117-3.3 power conversion chip is by 5V electricity Pressure is converted to 3.3V voltage stabilizing chip, and AMS1117-1.8 power conversion chip is the voltage stabilizing chip that 3.3V voltage is converted to 1.8V.

Logic synthesis circuit 3 is the two-way difference generating the comparing unit of task manager EVA in DSP control chip 2 The phase sequential signal of complementary PWM ripple and stepper motor 6 carries out logic synthesis, and the present embodiment uses proprietary logic gate device 74HC08 Realize, make circuit design relatively simple, be easier to realize.74HC08 is 4 inputs and gate device, by two-way PWM ripple complementary respectively With the phase sequential signal phase of control stepper motor 6 with after, generate and there is the phase sequential signal of copped wave.Phase sequential signal input after chopped To power driver module, the break-make of control switching tube, the phase sequential signal after copped wave is possible to prevent to cause because of energy accumulating Stepper motor 6 vibrates.Furthermore, PWM ripple and 4 tunnel phase sequential signal phases with after, by changing the dutycycle of PWM ripple, equivalence generates rank Ladder waveshape, and the PWM generating is passed through power driver module, thus realize changing each phase flexibly by DSP control chip 2 The on off operating mode of winding.

As it is shown on figure 3, logic synthesis circuit 3 receives the signal of DSP control chip 2, PWM1, PWM2, PWM3, PWM4 are respectively Being produced by the GPIOA0-GPIOA4 pin of DSP control chip TMS320F2812, A phase ,/A phase, B phase, the phase sequential signal of/B phase make With GPIOG0, GPIOG1, GPIOG2, GPIOG3 pin of TMS320F2812.Logical device 74HC08 in logic synthesis circuit 3 Four road signal Y1, Y2, Y3, Y4 of output correspond respectively to IN1, IN2, IN3, IN4 of L298N chip in power driving circuit 5 Pin.

Because the PWM ripple of DSP control chip 2 output is data signal, its frequency is very high, but voltage and current is very Low, driving force is low, and it also requires level conversion, it is impossible to directly drive L298N, otherwise have interference, make stepper motor 6 not Can normally work, it is therefore desirable to 74HC08 and L298N is carried out Phototube Coupling, so can avoid because of both sides (i.e. DSP control The PWM ripple of chip 2 output and the PWM ripple being input to driving chip, side is DSP control chip 2, and side is drive circuit) letter The problem that number current potential does not mates and cannot drive L298N, it is thus also avoided that the crosstalk between unlike signal, it is ensured that whole control system System stability.As shown in Figure 4, the present embodiment uses HCPL-0631 high speed photo coupling to isolate, in figure 4, it can be seen that electric capacity It is decoupling capacitor that C5 connects power end, and its effect is to ensure that the stability of input voltage, because switch can cause power supply electricity repeatedly Pressure fluctuation, and with the electric capacity that supply voltage is directly connected, the magnitude of voltage in the stable moment is the same with supply voltage, works as electricity When source voltage is less than theoretical value 5V, electric capacity charges to HCPL-063.Due to this circuit 5V voltage, electric capacity value 0.1uf, Ji Keman Foot requires.The 1st, the 4th, the 6th, 7 pin pull-up resistor R2, R3, R4, R5 of HCPL-0631 high speed photo coupling, its effect is to improve output level, The antijamming capability of intensifier circuit, the general value of pull-up resistor is 470 Ω-10k Ω.

D/A change-over circuit 9 is the major part realizing stepper motor 6 stepper angle fraction, in D/A change-over circuit 9 8 bit digital quantity of the segmentation value from DSP control chip 2 are converted to the analog quantity of stepper motor 6 electric current by DAC0832 chip, It is made stepped to rise or fall.The output of DAC0832 chip is current value, and what power driving circuit 5 needed that it exports is Therefore output be changed into magnitude of voltage at the external operational amplifier of DAC0832 chip by magnitude of voltage.As it is shown in figure 5, D0-D7 in DAC0832 chip is digital quantity input, and correspond respectively to be solidificated in the EPROM of DSP control chip is just remaining The digital quantity of the segmentation value in string function table, i.e. the D0-D7 input of the corresponding D/A module of GPIOD0-GPIOD7, the VrefA of output It is sent to power driving circuit 5.

As shown in Figure 6, the L298N that power driving circuit 5 uses enjoys a double blessing bridge driving chip, identical by two groups inside it Full-bridge circuit composition.Each full-bridge circuit is made up of four MOSFET and TTL logic circuits again, by logic level The different TTL logic level of input IN1, IN2, IN3, IN4 and Enable Pin EnA, EnB input, just can open different MOSFET, completes the forward and reverse energising control to motor winding.1 pin of L298N and 15 pins receive current sensing resistance R6 and R7 is upper is used for current sample.The two-way PWM ripple being produced by DSP control chip 2 be separately input to L298N chip Enable Pin EnA, EnB, in order to control the break-make of motor winding input voltage.By the logic level of the I/O mouth output of DSP control chip 2 through patrolling Four road signal Y1, Y2, Y3, the Y4 collecting circuit output are input to IN1, IN2, IN3, IN4 end of L298N for determining motor winding The direction of voltage.Using precision resistance R6 and the R7 measurement motor two-phase winding current of two 0.5 Ω/2W, sample rate current passes through ADC00, ADC01 deliver to the A/D modular converter of DSP control chip after treatment.Interface J6 receives on stepper motor, eight big work( Rate diode D1-D8 here functions as afterflow effect.

For preventing stepper motor 6 fault from burning, it is necessary to stop when machine winding current is too high powering motor, so It is designed with current foldback circuit between stepper motor 6 and DSP control chip 2.As it is shown in fig. 7, in circuit overcurrent protection LM358, by two divider resistance R9 and R10 by+5V voltage to 1V, delivers to comparator in-phase end, and R11 is positive and negative feed Resistance.A, B biphase current signal sent here by current sampling circuit send comparator end of oppisite phase through two diode D9 and D10, than Deliver to DSP control chip compared with device output PINTA end signal after level conversionPin.Comparator is reverse at ordinary times The voltage of end is relatively low, so its output PINTA end is all high level.Owing to the pressure drop of D10 and D9 forward conduction is about 0.7V, institute To trigger with the comparator when any one voltage of ADC00, ADC01 is more than 1.7V, export a low level at PINTA end. This low level signal will produce the interruption the highest of a grade inside DSP control chip, makes DSP control chip stop output PWM ripple, so that stepper motor power-off.Resistance R8 constitutes a filtering link together with electric capacity C6, and anti-locking system is done because of the external world Disturb false triggering.Owing to machine winding current sampling resistor is 0.5 Ω, the trigger voltage of corresponding 1.7V, current of electric is 3.4A, also I.e. when current of electric is more than 3.4A system by protection act.

The utility model is for two-phase hybrid stepping motor, and the core concept of its micro-stepping control controls motor exactly A, B two electric current of phase winding so that it is exporting corresponding electric current under the segmentation number designing, model is the DSP of TMS320F2812 Control chip output is stored in the corresponding segmentation i.e. TMS320F2812 of current sinusoidal table in EEPROM and produces Design of Stepper Motor Subdivision value Digital quantity, the utility model employs GPIOB least-significant byte output stepper motor segmentation value, the highest segmentation number be 256, And removing, according to the segmentation value producing, table look-up (the sin cos functions table being solidificated in EEPROM), EEPROM is DSP control chip Part.

The utility model employs two D/A conversion module, and therefore DSP control chip is also required to produce the selection of D/A module Signal, the DAC0832 of the double buffer mode that this module uses, the segmentation value of input determines the step-length of sine and cosine table, and DSP controls These digital quantities in sine and cosine table are converted into again the grading current value of stepper motor by chip, so that the electricity mutually of stepper motor Flowing stepped raising and lowering, being also achieved that the purpose of segmentation electric current, its result is the intrinsic step angle of stepper motor It is subdivided into some small steps, the problems such as torque drop during with regard to overcoming low-frequency oscillation, step-out and high-speed cruising.

In sum, the Multi-level microstep system that the utility model uses not only increases the precision of stepper motor, solves Degradation problem under low-frequency oscillation, high speed torque, also makes the utility model and driving that traditional single-chip microcomputer, FPGA control chip control Dynamic system is compared has the advantages such as low cost, volume is little, response is fast, use is safe, can well adapt to the demand of various occasion.

Claims (9)

1. a novel stepper motor drive system, it is characterised in that: include host computer, DSP control chip, D/A change-over circuit, Motor drive module, power circuit and stepper motor, described motor drive module includes power driving circuit；

Described host computer is bi-directionally connected with DSP control chip, the input of the output of described power circuit and DSP control chip Connecting, the output of described DSP control chip connects motor drive module and the input of D/A change-over circuit, described D/A respectively The output of change-over circuit connects the input of power driving circuit in motor drive module, the output of described motor drive module End connects the input of stepper motor；

Described host computer is for sending instruction to DSP control chip, and described D/A change-over circuit is used for will be from DSP control chip The digital quantity of Design of Stepper Motor Subdivision value be converted to analog quantity, and this analog quantity is sent into power driving circuit, described motor drives Dynamic model block rotates according to the signal controling stepping motor of DSP control chip, and described power circuit is for providing to DSP control chip Operating voltage.

2. novel stepper motor drive system according to claim 1, it is characterised in that: described motor drive module also wraps Include logic synthesis circuit, the PWM ripple complementary respectively of the two-way for generating task manager EVA in DSP control chip and step The phase sequential signal entering motor carries out logic synthesis, and the input of described logic synthesis circuit connects the output of DSP control chip, Its output is connected with the input of power driving circuit by photoelectric isolating circuit.

3. novel stepper motor drive system according to claim 2, it is characterised in that: described logic synthesis circuit includes Logic gate device 74HC08.

4. novel stepper motor drive system according to claim 1, it is characterised in that: also include tachometer circuit, be used for Test the speed of stepper motor and turn to, and test result being shown by host computer, the input of described tachometer circuit Connecting the output of stepper motor, its output connects the input of DSP control chip.

5. novel stepper motor drive system according to claim 4, it is characterised in that: described tachometer circuit includes one The photoelectric encoder of two-phase.

6. novel stepper motor drive system according to claim 5, it is characterised in that: described photoelectric encoder model is E6A2-CW3C。

7. novel stepper motor drive system according to claim 1, it is characterised in that: also include over-current detection circuit, For preventing stepper motor fault from burning, the input of described over-current detection circuit connects stepper motor, and its output connects DSP Control chipPin.

8. novel stepper motor drive system according to claim 1, it is characterised in that: described power circuit includes two The voltage conversion chip of series connection, for changing supply voltage to operating voltage needed for DSP control chip.

9. novel stepper motor drive system according to claim 1, it is characterised in that: the type of described DSP control chip Number being TMS320F2812, described power driving circuit includes that L298N enjoys a double blessing bridge driving chip.