KR950010666B1 - Switched reluctance motor driving circuit - Google Patents

Abstract

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Description

Switched Reluctance Motor Drive Circuit

1 is a configuration diagram of a rotor and a sensor of a conventional switched reluctance motor.

FIG. 2 (a) is a structural diagram of a stator and a rotor of a conventional switched reluctance motor, and FIG. 2 (b) is a structural diagram of a sensor disk of a conventional switched reluctance motor.

3 is a waveform diagram of each part of FIG.

4 is an excitation signal waveform diagram output from the logic circuit of FIG.

5 is a circuit diagram of a switched reluctance motor of the present invention.

6 is a modified circuit diagram of the circuit of the present invention.

7 is another modified circuit diagram of the circuit of the present invention.

8 is a waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: rotor 2: sensor disk

3: light emitting sensor 4: light receiving sensor

6 stator 8 stator stimulation

11-13, 40-45: switch part 17, 19, 20: freewheeling part

28, 30, 32: synthesis section 34, 36, 38: low pass filter

S ₁ , S ₂ , S ₃ : Position detection sensor

R ₁ to R ₆ , R ₁₄ to R ₁₆ , R ₁₇ to R ₂₂ : current detection resistance

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switched reluctance motor. In particular, the position of the rotor can be accurately detected without using a position detection sensor by detecting the position of the rotor using a current flowing in the switched reluctance motor winding. The invention relates to a switched reluctance motor driving circuit which can be detected.

The rotor and sensor configuration of the conventional switched reluctance motor are shown in FIG. 1, and the rotor 1 rotates when a magnetic field is generated by the stator stimulation, and is installed on the shaft of the rotor 1 and rotates. A sensor disk 2 that rotates simultaneously with the electron 1 and a position detection sensor S ₁ to S that detects a state of light blocked or passed by the sensor disk 2 when the sensor disk 2 rotates. ₃ ) and a logic circuit 5 for outputting the excitation signals PH-a, PH-b, and PH-c when the position detection signal is inputted from the position detection sensors S ₁ to S ₃ . .

The operation of the conventional switched reluctance motor rotor and sensor will be described in detail with reference to FIGS. 1 to 4 as follows.

Second, the sensor disk (2) having the projection (9) and the opening 10, such as b0, is manufactured and installed on the rotor 1, and rotating the rotor 1 also rotates the sensor disk (2) at the same time do.

When the sensor disk 2 is rotated, the light generated by the light emitting sensors _{3 of} the position detection sensors S ₁ , S ₂ , and S ₃ passes through the protrusion 9 and the opening of the sensor disk 2. It is interrupted by (10), and the signal of the waveform shown in FIG. 3 is output as it is detected by the light receiving sensor 4.

As such, the signals output from the position detection sensors S ₁ , S ₂ , and S ₃ are inputted from the logic circuit 5 of FIG. PH-b and PH-c are outputted, and the phase excitation signals PH-a, PH-b, and PH-c are inputted to the terminals INa, INb, and INc of FIG. The rotor La is rotated by exciting the winding La, the B-phase winding Lb, and the C-phase winding Lc in turn.

However, in the driving circuit of the conventional switched reluctance motor, the position detection sensor must be mounted on the motor, so various mechanical processings are required, and a space for installing the position detection sensor must be secured, and the inside of the motor has a high temperature or a compressor. There was a problem that the position detection sensor malfunctions when splashing the refrigerant lubricating flow causing congestion.

In view of such a conventional problem, the present invention detects a current flowing through a winding of a switched reluctance motor as a voltage without using a position detection sensor, and obtains the position information of the rotor from the detected voltage to switch the reluctance motor. Created a switched reluctance motor driving circuit used as a drive signal, which will be described in detail with reference to the accompanying drawings.

FIG. 5 is a circuit diagram of a switched reluctance motor according to the present invention. As shown in FIG. 5, when a pulse width modulation signal PWM is input to the base, the switch is switched on and off according to the pulse width modulation signal PWM. A switching unit 11 for controlling a current flowing through the current, and a current flowing toward the A-phase winding La through the current detecting resistor R ₁ and the diode D ₁ during the off period of the switching unit 11. After inverting the voltage detected by the wheeling unit 17 and the freewheeling unit 17 through the analog inverter 26, the voltage detected by the switching unit 11 and the analog adder 27 are output. And a low pad filter 34 for low-passing the signal synthesized and output from the synthesizer 28. The switching unit 11 is configured to provide a positive terminal of the DC voltage Vdc. the pulse width modulated signal applied to the transistor receiving (PWM) to the base (Q ₁₎ a phase winding (La), Pearl Through width modulation signal transistor receives is the (PWM) to the base (Q ₂₎ and a current detecting resistor (R ₂₎ are sequentially connected to the negative terminal of the DC voltage (Vdc), and the A-phase winding (La) and a transistor The collector connection point (Q ₂ ) is connected to the positive terminal of the DC voltage Vdc through the diode D ₂ , and the freewheeling unit 17 connects the negative terminal of the DC voltage Vdc to the current detection resistor. It is configured by connecting to the connection point of the emitter and the A-phase winding La of the transistor Q ₁ through (R ₁ ) and diode D ₁ . The switching section 12, 23, freewheeling section 19, 20, combining section 30, 32, and low pass filter 36 are also applied to the B and C phases in the same manner as described above. And (38).

FIG. 6 is a modified circuit diagram of the circuit of the present invention described with reference to FIG. 5, and as shown therein, a transistor Q ₁ and a current to which a plus end of the DC voltage Vdc is applied to the base of the pulse width modulation signal PWM. The detection resistor R ₁₄ , the A-phase winding La, and the transistor Q ₂ receiving the pulse width modulation signal PWM are sequentially connected to the negative terminal of the DC voltage Vdc. The collector connection point of the A-phase winding La and the transistor Q ₂ is connected to the positive terminal of the DC voltage Vdc through the diode D ₂ , and the negative terminal of the DC voltage Vdc is connected to the diode D _1. Is connected to the connection point of the emitter and current detection resistor R ₁₄ of the transistor Q ₁ to form a switching unit 40, and the switching units 41 and 42 for the B and C phases are also Configured in the same manner as the switching unit 40, the current detection resistors R ₁₄ , R ₁₅ , and R of the switching units 40, 41, and 42 are The voltage signal detected by R ₁₆ is configured to be input to the low pass filters 34, 36, and 38.

FIG. 7 is another modified circuit diagram of the circuit of the present invention described with reference to FIG. 5, in which the positive end of the DC voltage Vdc is applied to the winding L ₁ and the pulse width modulation signal PWM is applied to the base. through the receiving transistor (Q ₁₎ and the current detection resistor (R ₁₇₎ connected to the negative terminal of the DC voltage (Vdc), and the resistance to the negative terminal of the DC voltage (Vdc) (R _18), winding (L ₂₎ And a connection point of the emitter of the transistor Q ₁ and the current detecting resistor R ₁₇ to the input side of the analog adder 27 by connecting to the positive terminal of the DC voltage Vdc through the diode D ₁ . And a connection point of the resistor (R ₁₈ ) and the winding (L ₂ ) to the input side of the analog inverter (26) to form a switching unit (43), and the switching unit (44) for B and C phases. ) And (45) are also configured in the same manner as the switching unit 43.

The operational effects of the present invention configured as described above will be described in detail with reference to the waveform diagram of FIG.

In FIG. 5, when the pulse width modulation signal PWM is input to the bases of the transistors Q ₁ and Q ₂ of the switching unit 11 as shown in FIG. 8A, the pulse width modulation signal PWM is measured. The transistors Q ₁ and Q ₂ are conducted in the high potential section, and the operations of turning off the transistors Q ₁ and Q ₂ in the low potential section of the pulse width modulation signal PWM are repeated. Therefore, while the transistors Q ₁ and Q ₂ are conducting, the transistor Q ₁ , the A-phase winding La, the transistor Q ₂ , and the current detection resistor R ₂ at the positive end of the DC voltage Vdc. ) it is a voltage equal to the negative end, because the current flows to the voltage drop generated in the current detection resistor (R ₂₎ a connection point (b) help to claim 8 (b) of the DC voltage (Vdc) is generated through.

That is, at this time, the current increases by the inductance of the A-phase winding La during the period in which the transistors Q ₁ and Q ₂ are conducting, and the diode D ₂ and the current detection resistor R ₁ during the period in which the transistors Q ₁ and Q ₂ are turned off. ) And through the diode D ₁ .

Therefore, during the period in which the transistors Q ₁ and Q ₂ are turned off, the current detection resistor R ₁ , the diode D ₁ , the A-phase winding La, and the diode ( Since a current flows through D ₂ ), a voltage drop occurs at the current detection resistor R ₁ to generate a voltage equal to the eighth (c) degree at the connection point a.

As a result, as the transistors Q ₁ and Q ₂ repeat the on / off operation by the pulse width modulated signal PWM, the emitter and the current detecting resistor R of the transistor Q ₂ due to the direction of current flow. ₂ ) A positive potential as shown in (b) of FIG. 8 is generated at the connection point (b) of FIG. 8, and a negative point as shown in FIG. 8 (c) to the connection point (a) of the current detection resistor R ₁ and the diode D ₁ . Of electric potential occurs.

As such, the voltage Va generated at the connection point a is inverted by the analog inverter 26 and then applied to the analog adder 27 through the resistor R ₇ and at the same time, the voltage Vb generated at the connection point b. ) Is commonly applied to the analog adder 27 through the resistor R ₈ and synthesized, so that a signal like the eighth (c) is output from the analog adder 27.

In order to drive the switched reluctance motor without using a sensor, the shape of the current flowing through the switched reluctance motor winding is important information and the low pass of the output voltage V ₃ of the synthesis unit 28 so as not to have a discontinuity point. When the filter is filtered through the filter 34, the voltage V _{3 of the} waveform shown in FIG. 8 (e) is output. The voltage V ' ₃ of the output waveform is differentiated by the differentiator, and then the zero crossing point is detected, and the detection signal is utilized as position information of the rotor for controlling the motor.

In the modified circuit of the present invention shown in FIG. 6, current detection resistors R ₁₄ and R in series with the A phase winding La, the B phase winding Lb and the C phase winding Lc of the switched reluctance motor ₁₅ ) and (R ₁₆ ), the current waveforms flowing through the windings La, Lb, and Lc of each phase can be detected as voltage even with one current detection resistor (R ₁₄ , R ₁₅ , R ₁₆ ). In addition, the detection voltage of the waveform passes through the low pass filters 34, 36, and 38 to be used as position information of the rotor for driving control of the switched reluctance motor.

Another modified circuit of the present invention shown in FIG. 7 has the same function as the circuit of the present invention of FIG. 5, that is, the transistor according to the pulse width modulation signal PWM applied to the base of the transistor Q ₁ . (Q ₁ ) repeats the on / off operation, so that while the transistor (Q ₁ ) is conducting, the positive voltage at the connection point (b) of the emitter and resistor (R ₁₇ ) of transistor (Q ₁ ) Vb is generated, and while turned off, a negative voltage Va is generated at the connection point a of the resistor R ₁₈ and the winding L ₂ , and this negative voltage Va is generated by the analog inverter 26. After inverting through), the positive voltage Va and the analog adder 27 are synthesized, and the synthesized voltage is filtered through the low pass filter 34, so that the position information of the rotor for the controlled reluctance motor driving control is obtained. It can be used as.

As described in detail above, the present invention detects a current flowing through a winding of a switched reluctance motor as a voltage without using a position detection sensor in an environment where a high temperature or a refrigerant lubricating oil such as a compressor splashes and causes a crowded pattern. Since the position information of the rotor can be obtained from the detected voltage, it is possible to reliably drive control the switched reluctance motor, and the structure thereof becomes simpler and smaller.

Claims (5)

Switch units 11, 12 for receiving the pulse width modulation signal PWM and controlling the flow of current in each phase winding La, Lb, Lc by repeating the on / off operation according to the pulse width modulation signal PWM. 13 and the phase windings La through the current detection resistors R ₁ , R ₃ , R ₅ and diodes D ₁ , D ₃ , D ₅ during the off periods of the switching units 11, 12, 13. , The freewheeling parts 17, 19, and 20 for flowing a current to La, Lc, and the voltage detected by the flow of current in the freewheeling parts 17, 19, and 20 to the analog inverter 26. Synthesizing unit 28, 30, 32 for synthesizing and outputting the voltage detected by the current flow in the switching unit 11 and the analog adders 27, 25, 33 after inverting, and the synthesis unit 28, A switched reluctance motor drive circuit comprising a low pass filter (34, 36, 38) for low-passing an output signal of 30, 32. 2. The switching unit 11 of claim 1, wherein the switching unit 11 applies a positive terminal of the DC voltage Vdc to the base of the transistor Q ₁ , the A-phase winding La, and the pulse width modulation. The transistor Q ₂ and the current detecting resistor R ₂ receiving the signal PWM to the base are sequentially connected to the negative terminal of the DC voltage Vdc, and the collector side connection point of the transistor Q ₂ is connected. Switched reluctance motor drive circuit, characterized in that connected to the positive terminal of the DC voltage (Vdc) via a diode (D ₂ ). 3. The transistor Q ₁ emitter of the switching unit 11 according to claim 2, wherein the freewheeling unit 17 connects the negative terminal of the DC voltage Vdc through the current detection resistor R ₁ and the diode D ₁ . And a connected reluctance motor driving circuit configured to be connected to a connection point of the A-phase winding La. 2. The switching unit 11 according to claim 1, wherein the switching unit 11 is a transistor Q ₁ , a current detecting resistor R ₁₄ , and an A-phase winding in which a positive end of the DC voltage Vdc is applied to the base of the pulse width modulation signal PWM. (La) and the transistor (Q ₂ ) to which the pulse width modulated signal (PWM) is applied to the base are sequentially connected to the negative terminal of the DC voltage (Vdc) and the connection point is connected through the diode (D ₁ ). The connection point of the transistor Q ₁ and the current detection resistor R ₁₄ and the collector side connection point of the transistor Q ₂ are connected to the positive terminal of the DC voltage Vdc through the diode D ₂ . The voltage detected by the current detection resistor R ₁₄ is directly input to the low pass filter 34, and the switching units 12 and 13 are configured in the same manner as the switching unit 11. Switched reluctance motor drive circuit. 2. The switching unit 11 of claim 1, wherein the switching unit 11 applies a winding L ₁ of the positive terminal of the DC voltage Vdc, a transistor Q ₁ , and a current detection resistor (R) to which the pulse width modulation signal PWM is applied to the base. R ₁₇ ) is sequentially connected to the negative terminal of the DC voltage Vdc, and the negative terminal of the DC voltage Vdc is connected to the current detecting resistor R ₁₈ , the winding L ₂ , and the diode D ₁ . The voltages detected by the current detection resistors R ₁₇ and R ₁₈ are sequentially connected to the positive terminal of the DC voltage Vdc through the analog adder 27 and the analog inverter of the combiner 28. And a switching unit (12, 13) are configured in the same way as the switching unit (11).