Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
  • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
  • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
  • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation

Definitions

• the invention relates to a circuit arrangement for an asynchronous motor drive of controlled stepping, i.e. for the control of the number of revolutions of asynchrous squirrel-cage motors,braking and the realization of highly accurate driving units.
• control of the motor may be performed with characteristics,which are well suitable fee the optimal control-technical and energetic adjustment of the drive unit.
• the aim of the invention is to eliminate the above mentioned drawbacks by providing an expedient circuitarrangement.
• control of the motor may be performe ⁇ l by the aid of simple means and with high accuracy.
• the essence of the invention is represented by the pulse- width modulator on sine basis,provided with current control according to figure 1, which is delivering the signals needed for pulse-width control;
• the invention relates to a circuit arrangement for an asynchronous motor drive of controlled stepping and the control of the number of revolutions of asynchronous squirrel-cage motors,respectively, braking and the realization of highly accurate driving units.
• the solution can be characterized in,that to the output of the supply unit one of the connecting points of the potentiometer is connected,while to the same potentiometer the common terminal of adjusting resistors has been connected.
• the other terminal of the first resistor is connected to one of the inputs of the switch - inductance, while to the otlier output of the same the collector of the transistor is connected.
• the emitter of the transistor is connected to the negative pole of the supply unit, while one of the switch points of the outcoupling coil of the switch-inductance is connected to one of the inputs of the NAND - gate having several inputs,while the other terminal of the outcoupling coil is connected to the earthpoint and in the magnetic coupling being common for the switch- inductance and the outcoupling coil, there is a pre- magnetizing inductive coil arranged.
• the system contains circuit arrangements consisting of the switch-inductance, the resistor,as well as the transistor of analogue lay out and connected in series,built into the system in a proper number,at last the N-AND-gate is connected through the switch-amplifier to the control input of the inverter.
• Figure 1 is showing the pulse-width modulator
• FIG. 2 the entire block-schematic of the drive
• Figure 4 illustrates a further preferable embodiment of the circuit arrangement according to the invention.
• one of the connecting points of the .potentiometer P is connected to the output of the D.C.supply unit T, whereas the other connecting point of the potentiometer P is connected to one of the common terminals of the adjusting resistors R 1 ,R 2 ,R 3 , R 4, R 5 and R 6 .
• the other connecting point of the resistor R 1 is connected to one of the outputs of the switch- inductance L 1 , while the collector of the transistor T 1 is connected to the other input of said switch inductance L 1 .
• the emitter of the transistor T 1 is connected to the negative terminal of the supply unit T. Simultaneously one of the switching points of the outcoupling coil of the switch-inductance L 1 has been connected to one of the inputs of the NAND-gate N provided with more inputs.
• the o ther output, of the outcoupling coil is connected to the earthpoint.
• the control coil E 1 belongs also to the switch-inductance L 1 .
• the task of said coil is to bring the switch-inductance L 1 into a magnetized state being proportional to the current of the motor.
• the system contains as many circuits being analogue in respect to layout and consisting of the resistor R 1 , the switch-inductance L 1 and the transistor T 1 connected in series,as many pulses are needed for inducing the half-wave of the phase voltage of the motor.
• These circuits - being absolutely identical with each other - are connected to the first circuit arrangement in such a manner,that the common points of the single resistors R 1 . . . .R n are connected to one of the terminals of the potentiometer, while the common emitter points of the transistors of the previously mentioned circuits connected in series are connected to the negative terminal of the supply unit T.
• One of the outputs of the outcoupling coils of the single switch-inductances L 1 .... L n is connected to the negative terminal of the supply unit T, while the other output is connected to an, input each of the NAND -gate N with several inputs. Simultaneously the output of the NAND-gate N is connected to the input of the switch- amplifier K, the output of which having been connected to the control input of the pulse-width modulator I.
• the premagnetizing inductive coils belonging to the single switch - inductance are connected in series.
• the main characteristics of the resistors R 1 ,R 2 ??R 6 applied therein lies in,that their values are changing in dependence of the amplitude of the sine function.
• the resistors may be of the same value.
• the premagnetizing inductive coils E 1 ,E 2 ,E 3 ,E 4 , E 5 E 6 are induced by an signal being proportional to current-signal of the motor current.
• the switch-amplifier which is serving for the drive of the bridge-branch of the pulse-width modulator,is connected to the output of NAND-gate N with six inputs.
• three units are to be formed from the pulse-modulator consistsing of the switch-inductance L 1,the resistor R 1 and the transistor T 1 ,the schematical arrangement is best seen in figure 2, wherein is shown that three AND- gates each with several inputs are connected to the previously described pulse-width modulator I.
• a three-phase generator H To one of the inputs of the AND-gates a three-phase generator H and altogether three time-genarators J 1 ,J 2, J 3 are connected.
• the signals of the three-phase generator H, as well as the signals of the time- generator J 1 ,belonging to the first phase, of the three-phase generator are to be seen in figure 3.
• a further preferred embodiment of the circuit arrangement according to the invention is shown in figure 4.
• the single phases of the three-phase mains are connected to the input of the three-phase mains rectifier E 1 .
• the output of the rectifier E 1 is connected to the input of a transistored chopper C,while the output of the same chopper is connected via the choke-coil F to the heavy-current input of the inverter Iv and after having been branched before said input, it is fed back via, the diode D 1 to the positive output of the rectifier Ei.
• the output of the dual driving circuit Y is connected to the control input of the chopper C and to the input of the driving circuit Y the current transformers /shunt-resistors/— having been connected to the output of the inverter Iv - are connected via the amplifier Er.
• the driving circuit V is built up,as follows:
• the output of the constant frequency timebasis- generator 5 is connected to the input of the flip-flop circuit Ik,whereas one of the outputs of the same is , connected to the input of the pulse-width modulator I.
• the output of said modulator is connected through the OR-gate to the previously mentioned switch - amplifier K, while the other output is connected via the level- translator Sz to the input of a further pulse-width modulator I, being absolutely identical with the previous one, whereas the output thereof is connected to the other input of the switch - amplifier K via the same OR-gate.
• the circuit arrangement according to the invention functions,as follows: In the usual way D.C. voltage is generated from the three-phase mains and led onto the chopper C.After having left the chopper C, the voltage,is supplied into the system through the choke-coil F. In the present circuit arrangement the voltage needed for the inverter Iv and defined by the parameters of the motor is generated by controlling the chopper. The operation of the chopper is controlled by the signal formed from the motor current.
• the timebasis-generator G generates the constant pulse frequency f 0 ,from which a signal being identical with the flip-flop circuit Ik with two outputs and an anti phase signal are formed /see figure 4/. The two signals appear at the outputs Q and Q of the flip-flop circuit.
• the signal of the output Q is transformed into a signal with a level similar to that of the original signal.
• the pulse-width modul ator I is operatdd with the previously mentioned signals; the modulator is driving the switch -amplifier K via the OR-gate,wheyeby the control of the chopper C is also taking place.
• the circuit arrangement consisting of the resistor R 1 ,the inductance L 1 is switched to the voltage - attenuated by the potentiometer P - whereby the intensity of the current will increase in the circuit arrangement with a slope depending on the choice of the elements as long as the inductance L 1 becomes saturated.
• the voltage attenuated by the po tentiometer arrives in its entj ⁇ ?ety to the resistor R 1 , accordingly , on the outcoupling coil a voltage- pulse depending on the saturation time of the iron will be generated.
• the inductive premagnetizing coils E 1 E 6 are induced by a current signal being proportional to the current-signal of the motor current.
• the driving circuit is connected to the output of the NAND-gate with six inputs and serves for driying the bridge- branch of the pulse-width modulator.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Stepping Motors (AREA)
• Control Of Electric Motors In General (AREA)
• Control Of Motors That Do Not Use Commutators (AREA)
• Control Of Ac Motors In General (AREA)
• Inverter Devices (AREA)
• Control Of Multiple Motors (AREA)
• Electromechanical Clocks (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10996901

Family Applications (1)

Country Status (7)

Citations (7)

Family Cites Families (7)

• 1979
  • 1979-10-02 HU HU79GO1459A patent/HU180770B/hu not_active IP Right Cessation
• 1980
  • 1980-10-02 WO PCT/HU1980/000004 patent/WO1981001084A1/en active IP Right Grant
  • 1980-10-02 AT AT80901888T patent/ATE18618T1/de not_active IP Right Cessation
  • 1980-10-02 JP JP50222780A patent/JPS56501310A/ja active Pending
  • 1980-10-02 DE DE8080901888T patent/DE3071487D1/de not_active Expired
• 1981
  • 1981-04-21 EP EP80901888A patent/EP0036424B1/en not_active Expired
  • 1981-05-29 DK DK237281A patent/DK237281A/da not_active Application Discontinuation

Patent Citations (7)

Non-Patent Citations (1)

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