KR100445656B1 - Operating circuit of switched reluctance motor including low price type current limiting circuit - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit of a switched reluctance motor (hereinafter referred to as SRM) including a low-cost current limiting circuit. The current limiting unit is a comparison unit for generating a signal according to the signal generated from the current detection unit when the magnitude of the current detected from the current detection unit is greater than the reference value, and the continuous pulse signal generated from the control unit And a switch unit for blocking input from the modulator to the modulator, and a charging unit formed between the comparator and the switch to charge a predetermined voltage by a signal generated by the comparator. Even in the case of SRM sensing, the overcurrent can be blocked for more than a certain time. It is inexpensive to implement the SRM having a stability without having to use expensive equipment, and there is an effect that it is possible to prevent the malfunction or damage to the SRM.

Description

Operating circuit of switched reluctance motor including low price type current limiting circuit}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive circuit of a switched reluctance motor (hereinafter referred to as SRM) including a low-cost current limiting circuit, and in particular, is supplied to the motor so that the motor can be operated according to a plurality of phases having a set order. The present invention relates to a driving circuit of an SRM including a low-cost current limiting circuit which senses a magnitude of a current to prevent damage to a motor.

As shown in FIG. 1, the driving circuit of a general SRM includes a controller 10 in which a plurality of sequential pulse signals having a set phase difference and a continuous pulse signal continuously generated with a constant duty are generated, and the controller Compared to the magnitude of the sequential pulse signal and the continuous pulse signal generated from (10), when the magnitude of the continuous pulse signal is large, the modulator 20 and the signal generated from the modulator 20 generate a high signal. The inverter unit 30 controls the current supplied to the SRM 2 by the plurality of transistors Q1 to Q9 turned on and off, and the current is supplied to the SRM 2 by the inverter unit 30. The power supply unit 40 and the current sensing unit 50 for sensing the magnitude of the current supplied from the power supply unit 40 to the motor 2.

Here, the control unit 10 is the first, second and third pulse terminals (11, 12, 13) for generating the plurality of sequential pulse signals and the fourth pulse terminal (14) for generating the continuous pulse signal The modulator 20 receives the sequential pulse signals generated from the first to third pulse terminals 11, 12, and 13 and the continuous pulse signals generated from the fourth pulse terminal 14. When the continuous pulse signal is large, pulse width modulation (PWM) is performed through the plurality of comparators 21, 22, and 23 to output a high signal.

The modulator 20 is connected to the first to third pulse terminals 11, 12, 13 to prevent a reverse flow of a signal, and a plurality of diodes D1, D2, D3, and the plurality of diodes D1. , D2 and D3 and a plurality of resistors R1 to R6 connected in parallel between the comparators 21, 22, and 23, respectively, the plurality of comparators 21, 22, and 23, and the fourth pulse terminal. First to third pulses by supplying power to the resistors R7 and R8 connected between the plurality of resistors 14 and the plurality of resistors R1 to R6 respectively connected to the plurality of diodes D1, D2 and D3. A level power supply stage 23 for allowing the level of the sequential pulse signals generated from the terminals 11, 12, and 13 to be adjusted, and an operating power supply stage for supplying the operating power of the plurality of comparators 21, 22, and 23; 24) more.

On the other hand, the inverter unit 30 includes a plurality of transistors Q1 to Q6 turned on / off according to signals from the plurality of comparators 21, 22, and 23, the plurality of transistors Q1 to Q6, and a resistor. And a plurality of field effect transistors Q7, Q8, and Q9 connected through the R12, R13, and R14 to control the current supplied from the power supply 40 to the SRM 2. Q1 to Q6 are supplied with the operating power through the resistors R9, R10, and R11 from the operating power supply stage 24 that supplies the operating power to the plurality of comparators 21, 22, and 23 in the modulator 20. .

The power supply unit 40 includes a plurality of resistors R15 to R26, capacitors C1, C2 and C3, diodes D4 to D9, and the power supply unit 40 to supply an external power supply 41 to the SRM 2. The external power supply 41 is composed of a plurality of transistors Q10, Q11, Q12 that can be selectively supplied according to the phase in which the SRM 2 operates.

On the other hand, the current sensing unit 50 is composed of a plurality of resistors (R27, R28, R29) connected to the field effect transistors (Q7, Q8, Q9) connected to the power supply unit 40 from the inverter unit 30 When the field effect transistors Q7, Q8 and Q9 are turned on by the generated high signal, the current supplied to the SRM 2 is connected to the field effect transistors Q7, Q8 and Q9. , R28, R29 also flows, so that the magnitude of the supplied current can be confirmed.

The operation of the driving circuit of the general SRM configured as described above is as follows.

First, a plurality of sequential pulse signals having a phase difference set according to a plurality of phases in which the SRM 2 operates from the controller 10 are generated at the first to third pulse terminals 11, 12, 13, The continuous pulse signal from which the pulse signal having a constant duty is continuously generated is generated from the fourth pulse terminal 14.

The sequential pulse signal and the continuous pulse signal are input to the plurality of comparators 21, 22, and 23 through a plurality of diodes D1, D2, and D3 and resistors R1 to R8, respectively, and the continuous pulse signal is large. In this case, a high signal is output from the plurality of comparators 21, 22, and 23.

The plurality of transistors Q1 to Q6 are turned on / off according to the signals output from the plurality of comparators 21, 22, and 23 and accordingly, the plurality of field effect transistors Q7 and Q8 connected to the power supply 40. , Q9 is turned on / off so that a current is supplied from the power supply unit 40 along the phase of the SRM 2.

In this case, the current supplied to operate the SRM 2 also flows to the current sensing unit 50, so that the magnitude of the current supplied to the SRM 2 can be detected.

However, the driving circuit of the general SRM senses only the magnitude of the current corresponding to the set value when a current exceeding a set value is supplied when a current is supplied from the power supply unit 40 to the SRM 2. Because the discontinuous sensing is performed, it is not easy to block the supply of current to the SRM 2 when the current is supplied above the set value and does not fall below the set value for a predetermined time. There is a problem that may be malfunction or breakage due to this overcurrent.

In addition, in order to detect that the current above the set value does not fall below the set value for a predetermined time, an expensive device such as a hall sensor capable of continuously detecting the magnitude of the current must be used, thereby increasing the cost.

The present invention has been made to solve the above problems of the prior art, the object of which is to continuously detect the current in the case of configuring the SRM motor without expensive equipment that can continuously detect the magnitude of the current, such as a Hall sensor Therefore, when the current exceeding the set value is supplied for a certain period of time, the overcurrent can be effectively cut off, so it is stable at low cost, thereby preventing the continuous inflow of overcurrent, thereby preventing damage and malfunction of the SRM. To provide a driving circuit of the SRM.

1 is a circuit diagram showing a driving circuit of a general switched reluctance motor;

2 is a circuit diagram showing a current limiting part of a switched circuit of a switched reluctance motor of a switched reluctance motor including a low-cost current limiting circuit according to the present invention;

FIG. 3 is a graph showing normal operation waveforms of a drive circuit switched reluctance motor of a switched reluctance motor including a four-switch element 41 in accordance with the present invention;

4 is a graph showing an operating waveform in which current is cut off when an overcurrent is supplied according to a current limiting part of a driving circuit of a switched reluctance motor including a low-cost current limiting circuit according to the present invention.

<Explanation of symbols on main parts of the drawings>

60: comparator 61: comparator

70: charging unit D10: diode

C4: Capacitor 80: Switch Section

Q10: transistor

According to the characteristic of the driving circuit of the SRM including the low-cost current limiting circuit according to the present invention for solving the above problems, a plurality of sequential pulse signals and a constant duty having a phase difference set for driving the motor A control unit for generating a continuous pulse signal that is continuously generated, and a modulation unit for outputting a high signal when the continuous pulse signal is large by comparing the voltage magnitude of the continuous pulse signal and the sequential pulse signal generated by the controller; An inverter unit that is turned on / off according to an output signal of the modulation unit to turn on / off power supplied to the motor, a power supply unit supplying current to the motor by the inverter unit, and the motor by the power supply unit The current sensing unit for sensing the current supplied to the, and the magnitude of the current detected from the current sensing unit In a driving circuit of a switched reluctance motor, which includes a current limiting unit that blocks current from the power supply unit from being supplied to the motor in case of a stationary abnormality, the current limiting unit is provided when the magnitude of the current detected from the current sensing unit is greater than or equal to a reference value. A comparator for generating a corresponding signal, a switch unit which is turned on according to a signal generated from the comparator and blocks the continuous pulse signal generated from the controller from being input to the modulator, between the comparator and the switch unit And a charging unit which is formed at and is charged with a predetermined voltage by a signal generated by the comparison unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing a driving circuit of a general SRM, and FIG. 2 is a circuit diagram showing a configuration of a current limiting unit according to the present invention.

The current limiting unit of the SRM according to the present invention is a high signal is generated when the magnitude of the current sensed by the current sensing unit 50 for sensing the magnitude of the current supplied to the SRM (2) is greater than the set value The comparison unit 60, the switch unit 80 that is turned on / off according to the signal generated by the comparison unit 60, and is formed between the comparison unit 60 and the switch unit 80 and the comparison unit ( The charging unit 70 is configured to charge a predetermined voltage by the high signal generated at 60.

Here, reference numerals not described in FIG. 2 use the same reference numerals as in FIG. 1.

The comparator 60 inputs a voltage having a magnitude detected from the current sensing unit 50 to a non-inverting (+) terminal, and a comparator 61 to which a voltage corresponding to the set value is supplied to an inverting (-) terminal. And a set power supply terminal 62 for supplying power so that the set voltage is supplied to the comparator 61, and connected to the set power supply terminal 62 so that the set current is inverted in the comparator 61 ( The plurality of resistors R30 and R32 and the voltage sensed by the current sensing unit 50 have hysteresis and may be input to the non-inverting (+) terminal of the comparator 61. A plurality of resistors (R31, R33, R34) formed between the set power supply terminal 62 and the current sensing unit 50 so that the input terminal 91 formed in the comparison unit 60 is Even when a current flows through any one of the plurality of resistors R27, R28, and R29 of the current sensing unit 50, It can be parallel connected to the plurality of resistors (R27, R28, R29) to jihal.

On the other hand, the charging unit 70 and the diode (D10) to prevent the reverse flow of the signal generated from the comparator 61, the capacitor (C4) is charged with a predetermined voltage by the signal passing through the diode (D10) and The resistor R35 is connected between the diode D10 and the switch unit 80.

The switch unit 80 is connected to the transistor Q10 that is turned on when a signal is generated from the comparator 61, the transistor Q10, and the resistor R34 to supply bias power to the transistor Q10. The bias power supply stage 81 is formed.

Looking at the operation of the current limiting unit in the driving circuit of the SRM according to the present invention configured as described above are as follows.

3 is a graph showing the current 101 sensed by the current sensing unit, the waveform 102 in which the field effect transistor operates, and the current 103 supplied according to the phase of the SRM in the power supply unit.

First, when the current sensing unit 50 senses the magnitude of the current supplied to the SRM 2 and the sensing current is less than or equal to the set current magnitude, as shown in FIG. 3, the current sensing unit 50 The field effect transistors Q7, Q8, and Q9 are turned on / off by the current sensed by the current, and thus the current is supplied from the power supply 40 according to the phase in which the SRM 2 operates.

4 is a graph showing the current 104 sensed by the current sensing unit, the waveform 105 in which the field effect transistor operates, and the current 106 supplied according to the phase of the SRM in the power supply unit.

If the magnitude of the current sensed by the current sensing unit 50 is supplied over the set value, as shown in FIG. 4, the current having the magnitude sensed by the current sensing unit 50 is supplied to the comparator 61. When input, since the current input to the comparator 61 is larger than the set value, a high signal is output from the comparator 61, and the high signal passes through the diode D10 to charge the capacitor C4. At the same time, the transistor Q10 is turned on to turn off the field effect transistors Q7, Q8, and Q9.

Therefore, the power supply unit 40 does not supply the current according to the phase of the SRM (2), and as a result, the current sensed by the current sensing unit 50 is lost, so that the high in the comparator 61 No signal is generated.

At this time, the discharge starts from the capacitor C4 charged by the high signal of the comparator 61 to maintain the transistor Q10 in the on state.

That is, the current supplied to the SRM (2) forcibly by the capacitor (C4) until the current supplied from the power supply unit 40 to the SRM (2) is supplied above the set value and falls below the set value again Will be blocked.

As a result, when the magnitude of the current supplied from the power supply unit 40 to the SRM 2 is greater than or equal to the set current, it is forcibly forced by the power charged in the capacitor C4 until the magnitude becomes smaller than the set current again. Since the current is blocked from being supplied from the power supply unit 40 to the SRM 2, the SRM 2 is prevented from being damaged or malfunctioned due to overcurrent.

In the SRM driving circuit including the low-cost current limiting circuit of the present invention configured as described above, in the SRM discontinuously detecting the magnitude of the current supplied from the power supply unit, the overcurrent is blocked from being supplied to the SRM and the magnitude of the current is By inexpensively implementing a current limiting unit for blocking the current supplied to the SRM until it falls below the set value, there is an effect that can prevent the SRM is damaged and malfunction in advance because the overcurrent is supplied to the SRM.

Claims (5)

A control unit for generating a plurality of sequential pulse signals sequentially generated to drive a motor and a sequential pulse signal and a predetermined duty to generate a continuous pulse signal continuously generated, the continuous pulse signal generated by the controller and the A modulator that outputs a high signal when the continuous pulse signal is large by comparing the voltage magnitude of the sequential pulse signal, and an inverter unit that is turned on / off according to the output signal of the modulator and on / off power supplied to the motor; A power supply unit supplying current to the motor by the inverter unit, a current sensing unit sensing a current supplied to the motor by the power supply unit, and a magnitude of a current detected from the current sensing unit is greater than or equal to a set value. Consists of a current limiting unit to block the supply of current from the power supply to the motor In the drive circuit of a switched reluctance motor, The current limiter is a comparator for generating a signal according to the signal generated when the magnitude of the current sensed from the current detector is greater than or equal to a reference value, and the continuous pulse signal generated from the controller is turned on according to the signal generated from the comparator. A low-cost current limiting circuit comprising a switch unit for blocking input to the modulation unit, and a charging unit formed between the comparison unit and the switch unit and charged with a predetermined voltage by a signal generated from the comparison unit. SRM drive circuit included. delete The method of claim 1, The comparator includes: a comparator for inputting a voltage having a magnitude corresponding to the magnitude and a reference value detected by the current sensing unit; A reference power supply terminal for supplying a voltage having a magnitude corresponding to the reference value to the comparator; SRM drive circuit including a low-cost current limit circuit, characterized in that consisting of a plurality of resistors connected to the comparator and the reference power supply terminal. The method of claim 1, The switch unit is a transistor that is turned on / off according to the signal generated from the comparison unit; A power supply stage for supplying bias power to the transistor; SRM drive circuit including a low-cost current limiting circuit, characterized in that consisting of a plurality of resistors connected to the transistor. The method of claim 1, The charging unit and the diode to prevent the reverse flow of the signal generated from the comparison unit; A capacitor charged with a predetermined voltage by a signal from the comparison unit passing through the diode; SRM drive circuit including a low-cost current limiting circuit, characterized in that consisting of a resistor connected between the diode and the switch.