JPH11235083A - Rotor position detection device of sensorless switched-reluctance motor and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the rotor position detection device of a sensorless SR motor and a method thereof which can detect the position of a rotor without using a rotational position detection sensor and having an influence on the driving chracteristics of an SR motor. SOLUTION: This rotor position detection device is provided with a regenerative period termination detection circuit 31 for detecting the termination of a regenerative period generated at a stator winding 3, a step functional signal generation circuit 17 for generating a step functional signal, a switch 14 which applies voltage applied from a power source 19 to the stator winding 3 as a step functional voltage based on the step functional signal, an inductance detection circuit 16 for detecting voltage or current at the time of transient response generated at the stator winding 3 by the step functional voltage, and a rotational position detection circuit which detects the position of a rotor salient pole based on predetermined voltage or current so as to meet the detected voltage or current detected by the inductance detection circuit 16, and the position of the rotor salient pole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting the position of a rotor of a sensorless switched reluctance motor (hereinafter, referred to as a sensorless SR motor) which operates without a rotational position sensor. The present invention relates to detecting the position of a rotor while avoiding the influence of a regenerative current generated in a stator winding from a change in inductance of a stator winding that changes depending on a positional relationship between a stator and a stator.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional general SR motor and its driving circuit. 1 is a stator, 3 is a winding, 5
Is a rotor that rotates about the rotation shaft 4. The stator 1 includes six stator salient poles 2 and three sets of windings 3 (only a pair of U phases U1 and U2 are shown for simplicity). The rotor 5 is made of a laminated steel plate, extends radially outward from the rotation shaft 4 of the rotor 5, and has four rotor protrusions at uniform intervals in the circumferential direction around the periphery of the rotor 5. Pole 6
Is composed. Like the rotor 5, the stator 1 is also made of a laminated steel plate.

The windings 3 of the stator salient poles 2 facing each other in the diameter direction are connected in series so as to generate a magnetic field in the same direction to form a phase winding, and the number of windings is three (U, U). V,
W). Although V and W of the coil set are not shown for simplicity, the stator salient poles combined with the phase windings are denoted by “V” and “W”.

[0004] Reference numeral 7 denotes a drive circuit for driving the SR motor, and shows only a basic electric circuit used for exciting the U-phase windings U1 and U2 of the SR motor. 8
a and 8b are a pair of transistors for turning on and off the current flowing through the U-phase winding 3, and 9a and 9b are transistors 8a and
A diode for flowing back electromotive force generated when 8b is turned off in a regenerative direction, 10 is a bus voltage which is a power supply for supplying a current for driving an SR motor, and 11 is a rotational position of the rotor 5. A position detection sensor 12 is a control circuit for controlling ON / OFF of the pair of transistors 8a and 8b.

Next, the operation will be described with reference to FIGS. In the case of the SR motor, since the rotor salient pole 6 is magnetically attracted and rotated in a direction in which the magnetic resistance is minimized by exciting the stator salient pole 2, the excited stator salient pole 2 It does not depend on the magnetic pole. Therefore, the current supplied from the drive circuit 7 only needs to be a current in one direction.
Then, the phase windings U, V and W are sequentially excited, and the rotor salient poles 6 are excited.
Is rotated in synchronization with the salient poles 2 of the stator that are excited.

First, when the transistor pair 8a, 8b is turned on to the U-phase winding 3, a current flows in the order of the power supply 10, the transistor 8a, the windings U1 and U2, and the transistor 8b. When the transistor pair 8a, 8b is turned off, back electromotive force is generated in the windings U1 and U2. The energy of this back electromotive force is regenerated through the diode 9a → the winding U1 and U2 → the diode 9b. This excitation operation is sequentially performed on each of the windings U, V, and W to perform a rotation operation as a motor. The ON / OFF switching timing of the transistor pairs 8a and 8b is determined by the control circuit 12 based on information from the position detection sensor 11 that detects the rotational position of the rotor 5.
Done by

FIGS. 9A to 9D show the positional relationship between the stator salient poles 2 and the rotor salient poles 6. FIG. Explaining with reference to the U-phase, when a voltage is applied to the U-phase when the stator salient pole 2 and the rotor salient pole 6 are separated as shown in FIG. 9A, the stator salient pole 2 is excited and magnetized. The rotor salient pole 6 closest to the stator salient pole 2 is magnetically attracted by the attraction force. Due to the magnetic attraction, the rotor salient pole 6 approaches the stator salient pole 2 as shown in FIG. 9B. Further, the rotor salient poles 6 approach the stator salient poles 2, and the stator salient poles 2 and the rotor salient poles 6 face each other as shown in FIG. At this time, the suction force acting on the rotor salient pole 6 is only in the diameter direction, and no torque for rotating the rotor 5 is generated. Further, as shown in FIG.
Is rotated, a force in the rotational direction acts on the rotor salient pole 6 again, and a rotational torque is generated on the rotor 5. The rotation torque generated at this time is in the direction opposite to the directions shown in FIGS. Assuming that the rotor 5 is rotating clockwise, it becomes a braking force for stopping the rotation.

In order to rotate the rotor 5 in one direction,
The torque must always be generated in the same direction. Therefore, as shown in FIG. 9C, the excitation of the stator salient poles 3 must be stopped before the stator salient poles 3 and the rotor salient poles 6 face each other. As described above, in order to rotate the SR motor in a certain direction, it is necessary to switch the timing of energizing the stator winding 3 in synchronization with the position of the stator salient pole 2 with respect to the rotor salient pole 6. For this reason, conventionally, in order to detect the position of the rotor 4, the position of the rotor 5 is detected by a position detection sensor 11 such as a resolver, and the rotor position signal is fed back to the control circuit 12, thereby obtaining the stator. The salient pole winding 3 was energized in synchronization with the position of the rotor 5.

[0009]

However, by providing the position detection sensor 11 as in the conventional SR motor driving device, the number of connections coming out of the SR motor increases.
For example, when moving in a special space like a compressor,
The number of terminals for connecting the inside and the outside increases, and the shape and cost are restricted. Therefore, it is desirable that the position detection sensor 11 be unnecessary.

In the case of the SR motor, since there is no magnet in the rotor 5 as in the case of the DC motor, it is not possible to use the change in the magnetic flux linked to the stator winding 3. Therefore, the position of the rotor salient pole 6 is detected by utilizing the characteristic of the SR motor that the inductance of the winding 3 of the stator salient pole 2 changes depending on the position of the rotor salient pole 6 with respect to the stator salient pole 2. Can be.

FIG. 10 shows a general change in the inductance of the stator salient pole winding with respect to the rotation angle of the rotor salient pole. The rotation angle θ1 in FIG. 10 has the minimum inductance, and the positional relationship between the stator salient poles and the rotor salient poles is as shown in FIG. 9A. Then, when the clockwise rotation is performed as shown in FIG. 9B, the inductance of the stator salient pole winding increases as shown by θ2 in FIG. At the position shown in FIG. 9C, the maximum value is obtained as indicated by θ3 in FIG. Further FIG.
When rotated as shown in (d), the inductance decreases as shown by θ4 in FIG. As described above, the magnitude of the winding inductance of the stator salient pole depends on the position of the rotor salient pole with respect to the stator salient pole, as shown in FIG. SR that the inductance of the winding 3 of the stator salient pole 2 changes depending on the position
The position of the rotor salient pole 6 can be detected using the characteristics of the motor.

Accordingly, the position of the rotor salient pole with respect to the stator salient pole when exciting the stator winding is determined in advance, and the inductance of the stator winding at that time is determined. If the timing for exciting the stator salient poles is made, the stator salient poles can be excited in synchronization with the rotor salient poles without providing the position detection sensor 11 of FIG.

As described above, if the value of the inductance is known, the position of the rotor salient pole with respect to the stator salient pole can be estimated, but as can be seen from FIG. 10, it is symmetric about the rotor salient pole angle θ3. Therefore, the position of the rotor salient pole cannot be uniquely detected from the inductance value. However, when an arbitrary stator salient pole is excited due to the drive timing of the SR motor, the winding inductance of the stator salient pole that was excited immediately before is reduced. If the value is detected, the position of the rotor salient pole with respect to the stator salient pole is uniquely determined.

Thus, taking advantage of the characteristics of the SR motor,
As the detection of the position of the rotor salient pole by detecting the inductance of the stator salient pole winding, for example, a switching reaction motor without a shaft position sensor described in Japanese Patent Application Laid-Open No. H8-501920 is disclosed. The rotor position sensing device applies a continuously fluctuating signal to the non-excited stator salient pole windings of the SR motor, and as a result, detects the amplitude and phase of the output current to detect the position of the rotor. Has been detected. However, a continuously fluctuating signal and a circuit for amplifying the signal are required, and a switching circuit for connecting those signals to a stator salient pole winding that is not excited is required. However, there was a problem that it became complicated.

In the case of an SR motor, when a driving voltage is applied to the stator winding 3, magnetic energy is stored in the stator winding 3, and when the application of the driving voltage is cut off thereafter,
There is a regeneration period during which current is regenerated to bus voltage 10 through diode pairs 9a, 9b to consume the stored magnetic energy. This regenerative period may have an effect when detecting the inductance of the stator salient pole windings and detecting the position of the rotor salient poles.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a simple circuit can be used to reduce a regenerative current generated in a stator winding without using a dedicated rotational position detecting sensor. It is an object of the present invention to obtain a rotor position detecting device and a method of a sensorless SR motor that detects a rotor position while avoiding the influence.

[0017]

SUMMARY OF THE INVENTION A rotor position detecting device for a sensorless SR motor according to the present invention is configured such that when a drive voltage applied to a stator winding is cut off, a regenerative period in which a regenerative current flows ends. A step function signal generating circuit that generates a step function signal, and a resistor that is connected between a power supply and the stator winding and determines a time constant during a transient response;
A switch applied to the stator winding and the resistor as a step function voltage based on the voltage applied from the power supply based on the step function signal, and a voltage generated in the stator winding and the resistor by the step function voltage. Based on an inductance detection circuit that detects a voltage or a current at the time of a transient response, based on a detection voltage or a detection current detected by the inductance detection circuit and a voltage or a current that is predetermined according to the position of the rotor salient pole. A rotation position detection circuit for detecting the position of the rotor salient pole.

Further, when the drive voltage applied to the stator winding is cut off, a regeneration period end detection circuit for detecting the end of a regeneration period in which a regenerative current flows, and an output signal from the regeneration period end detection circuit. A step function signal generating circuit that generates a step function signal, and a resistor that is connected between a power supply and the stator winding and determines a time constant during a transient response;
A switch applied to the stator winding and the resistor as a step function voltage based on the voltage applied from the power supply based on the step function signal, and a voltage generated in the stator winding and the resistor by the step function voltage. Based on an inductance detection circuit that detects a voltage or a current at the time of a transient response, based on a detection voltage or a detection current detected by the inductance detection circuit and a voltage or a current that is predetermined according to the position of the rotor salient pole. A rotation position detection circuit for detecting the position of the rotor salient pole.

Further, a step function signal generating circuit for generating a step function signal, a resistor connected between the power supply and the stator winding and for determining a time constant during a transient response, and a voltage applied from the power supply, A switch applied to the stator winding and the resistor as a step function voltage based on a step function signal, and a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage is detected. An inductance detection circuit that compares a regenerative voltage or a current generated when the drive voltage applied to the stator winding is cut off with a predetermined level and outputs a detection signal; Based on the detection signal output by and the value of the voltage or current predetermined corresponding to the position of the rotor salient pole, A rotation position detection circuit that detects the position of the trochanter salient pole, and a control circuit that determines the end of a regeneration period of the regenerative voltage or current based on an output signal from the inductance detection circuit and drives the step function signal generation circuit. , Is provided.

Further, a step function signal generating circuit for generating a step function signal, a resistor connected between the power supply and the stator winding and for determining a time constant during a transient response, and a voltage applied from the power supply, A switch applied to the stator winding and the resistor as a step function voltage based on a step function signal, and a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage is detected. Detecting the position of the rotor salient pole based on a detection signal output by the inductance detecting circuit and a voltage or current value determined in advance corresponding to the position of the rotor salient pole. And a drive voltage applied to the stator winding to which a second drive voltage is applied after the drive voltage applied to the stator winding is cut off. When but it applied, and a control circuit for driving the step function signal generating circuit.

Further, the method for detecting the rotor position of the sensorless SR motor is characterized in that, when the drive voltage applied to the stator winding is cut off, the regenerative period in which the regenerative current flows ends.
Generating a step function signal, applying a voltage applied from a power supply as a step function voltage based on the step function signal to the stator winding via a resistor that determines a time constant during a transient response, The position of the rotor salient pole based on a voltage or current at the time of transient response generated in the stator winding and the resistor by a voltage and a voltage or current predetermined corresponding to the position of the rotor salient pole. Is to be detected.

Further, after the driving voltage applied to the stator winding is cut off, a step function signal is generated when the driving voltage is applied to the stator winding to which the driving voltage is applied second. As a step function voltage based on the step function signal, the voltage applied from the power supply is applied to the stator winding via a resistor that determines a time constant during a transient response,
Based on a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage and a voltage or current predetermined in accordance with the position of the rotor salient pole, the rotor salient The position of the pole is detected.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, Embodiment 1 will be described with reference to the drawings. FIG. 1 is a configuration diagram of a drive device for a sensorless SR motor including a rotor position detection device according to the first embodiment, and illustrates one phase for ease of description. FIG. 2 is an operation waveform diagram for explaining a relationship between a regeneration period and a step signal by a driving voltage of the stator winding, and FIG. 3 is a driving voltage applied to the stator winding, a driving current flowing through the stator winding, and a regeneration period. FIG. 5 is a waveform diagram of input / output voltages of an end detection circuit. In FIG. 1, 8a is a transistor connected between one end of the stator winding 3 and the bus voltage 10, 8b is a transistor connected between one end of the stator winding 3 and GND, and 9a is one end of the stator winding 3. 9b is a diode connected between the other end of the stator winding 3 and the bus voltage 10b.
, A detection power supply, 18
Is a control circuit for turning on / off the transistor pairs 8a and 8b by a stator winding excitation signal.

Numeral 25 denotes a rotor position detecting device for detecting the position of the rotor of the SR motor. The resistor 13 is connected between one end of the stator winding 3 and the detecting power supply 19 in parallel with the transistor 8a. A step function signal generating circuit 17 for generating a step function signal is connected to the other end of the stator winding 3 in parallel with the transistor 8b, and connected in series with the resistor 13 and the stator winding 3 to generate a step function signal. Circuit 1
ON-O based on the step function signal output from
The transistor 14 is a switching element that applies the detection power supply 19 as a step function voltage to the stator winding as a step function voltage, a regeneration period end detection circuit 31 that detects the end of the regeneration period from the input voltage V, and a resistor 13. Detecting circuit 16 which is connected from a connection point of the stator winding 3 and a voltage corresponding to the inductance of the stator winding 3 by a step function voltage, and is set in advance to a voltage output from the inductance detecting circuit 16. A rotation position detection circuit 15 that outputs a signal indicating the position of the rotor salient pole 6 based on a voltage corresponding to the position of the rotor salient pole 6, and a detection power supply 19 to eliminate the influence of the bus voltage 10. It is composed of a commutator 20 for preventing a current from flowing.

Next, the operation will be described with reference to FIGS. First, when the output voltage of the step function signal generation circuit 17 turns on, the transistor 14 turns on, and a current flows from the detection power supply 19 to the transistor 14 through the resistor 13, the stator winding 3, and the diode 20. The voltage V input to the inductance detection circuit 16 and the regeneration period end detection circuit 31 by the current flowing at this time is as follows: V = Vcc × exp (−R × t / L) (1) Here, Vcc is the voltage value of the detection power supply 19,
R is the resistance value of the resistor 13 connected between the detection power supply 19 and the stator winding 3, t is the elapsed time since the transistor 14 was turned on, and L is the inductance of the stator winding 3.

From the equation (1), the voltage Vcc of the detection power supply 19, the resistance value R of the resistor 13, and the transistor 14
If the elapsed time t after N is known, the inductance L of the stator winding 3 can be estimated from V.

The elapsed time t is defined as the detection time, and the value of the voltage V at this time is defined as the transient voltage Vsens. Then, the positional relationship between the stator salient pole 2 and the rotor salient pole 6 and the relationship between Vsens at that time are determined in advance.

Here, the effects of the regenerative current and the step function signal generated when the application of the drive voltage is cut off after the application of the drive voltage to the stator winding 3 will be described with reference to FIG. FIG. 2A shows a stator winding driving voltage waveform diagram, and FIG.
2 (b) is a stator winding driving current waveform chart when there is no step function signal generation circuit signal, and FIG. 2 (c) is a stator winding driving current waveform chart when there is a step function signal generation circuit signal. (D) is a waveform diagram of the stator winding inductance.

In the SR motor, when the transistor pair 8a, 8b is turned on, the drive current for the stator winding 3 of any one phase of U, V, W is changed to the bus voltage 10 → transistor 8a → fixed winding 3 → transistor. Current flows in the order of 8b, and magnetic energy is stored in the stator winding 3. Thereafter, when the transistor pair 8a, 8b is turned off, a back electromotive force is generated in the stator winding 3 to consume the stored magnetic energy. The energy of this back electromotive force is regenerated to the bus voltage 10 through the diode 9a → the fixed winding 3 → the diode 9b. When the regeneration is completed, the diodes 9a and 9b become O
The state becomes the FF state, and a circuit of the detection power supply 19 → the resistor 13 → the diode 20 → the stator winding 3 → the transistor 14 is formed.

As described above, the transistor pair 8 of the driving circuit
a, 8b, and the diodes 9a, 9b are all in the OFF state, and the period in which the inductance of the stator winding 3 detected during the period in which the stator winding is in a floating state is a detectable period. is there.

During this regeneration period, a step function signal is applied from the step function signal generation circuit 17 and when a step function voltage based on the step function signal is applied to the stator winding 3, the step function voltage is fixed. When the magnetic energy is stored in the slave winding and the step function signal is applied more times, the regenerative period is changed as shown in FIG. 2C, and the step function signal generating circuit signal shown in FIG. If not, it will be longer than the regeneration period.

For this reason, a regenerative current flows even during a period (braking period) in which no current is supplied to smoothly rotate the SR motor, so that the SR motor is braked and the position is detected. It is conceivable that the detectable period for performing the operation becomes short.

This embodiment has been made in order to avoid such an influence, and will be described with reference to FIG. FIG.
3A is a stator winding driving voltage waveform diagram, FIG. 3B is a stator winding inductance waveform diagram, FIG. 3C is a stator winding driving current waveform diagram, and FIG. 3D is a regeneration period. FIG. 3E is an output voltage waveform diagram of the end detection circuit, and FIG. 3F is a step function signal waveform diagram.

First, when a driving voltage is applied to the stator winding 3, as shown in FIG. 3A, even when the driving voltage of the stator winding is not driven, the stator winding 3 is not driven. 3C, the magnetic energy stored in the stator winding 3 is regenerated through the diode pairs 9a and 9b as shown in FIG. The period during which this current is flowing is the regenerative period, and the detectable period that can be detected avoiding this period is the period during which the stator winding drive voltage is OFF and the inductance changes as shown in FIG. It is.

Next, while the SR motor is being driven, it is input to the regeneration period end detection circuit 31, and the input voltage is as shown in FIG. 3 (d). That is, while the drive voltage is being applied to the stator winding 3, the voltage Vb of the drive voltage 10 is normally higher than the voltage value Vcc of the detection power supply 9, so that the regeneration period end detection circuit 31 The voltage is the voltage value Vcc of the detection power supply 19. When the drive voltage applied to the stator winding 3 is cut off, the regenerative current flows from the diode 9a to the stator winding 3 to regenerate the accumulated magnetic energy.
And is regenerated to the bus voltage 10 from the diode 9b.
At this time, since the diode 9a is ON, almost G
ND voltage (0 V). When the regeneration ends and the regenerative current stops flowing, the diode 9a is turned off, so that the voltage of the regeneration period end detection circuit 31 becomes the voltage value Vcc of the detection power supply 19.

Here, a current value at which the regeneration period can be determined to be determined is set, and a detection level corresponding to the current value is set. By detecting that the detection level has been reached, the end of the regeneration period is determined. it can. Thus, if the step function signal generation circuit 17 is driven, the position of the rotor can be detected by the step function voltage without extending the regeneration period.

That is, the regeneration period end detection circuit 31
FIG. 3 shows the relationship between the input voltage to the regeneration period end detection circuit 31 and
As shown in FIG. 3D, when the detection level corresponding to the current value at which the regeneration period can be determined to be ended is set to Vs, the output voltage of the regeneration period end detection circuit 31 becomes Vs as shown in FIG.
When it becomes s, it becomes a rising edge. Then, it detects this rising edge and outputs a detection signal to the control circuit 18. The control circuit 18 transmits a transmission enable signal for causing the step function signal generation circuit 17 to transmit a step function signal. Then, the step function signal generation circuit 1
7 outputs a step function signal as shown in FIG.

Next, in the inductance detecting circuit 16,
The voltage Vsens after the detection time from the input voltage V is output. The output voltage Vsens has a value corresponding to the position of the rotor salient pole 6 with respect to the stator salient pole 2. In the rotation position detection 15, the voltage Vsens output from the inductance detection circuit 16 is compared with a voltage corresponding to a predetermined positional relationship between the stator salient poles 2 and the rotor salient poles 6, and a predetermined fixed A position corresponding to the positions of the child salient pole 2 and the rotor salient pole 6 is detected, and a position detection signal is sent to the control circuit 18.

Then, the control circuit 18 calculates the timing for exciting the stator salient poles from the sent position detection signal, and outputs a signal for turning on or off the transistor pair 8a, 8b to the transistor pair 8a, 8b. Similarly, the same applies to the V phase and the W phase.

As described above, the influence on the regenerative current can be obtained simply by adding a simple and inexpensive circuit for comparing the value of the voltage V with the detection level without using the rotational position detection sensor. It is possible to detect the position of the rotor with high reliability without changing the characteristics of the SR motor by avoiding the extension of the regeneration period).

Embodiment 2 Hereinafter, the second embodiment will be described with reference to the drawings. FIG. 4 is a configuration diagram of a driving device for a sensorless SR motor including the rotor position detection device according to the first embodiment, and FIG. 5 is a configuration diagram of the inductance detection circuit of FIG. 4, which is a general detection circuit. FIG. 6 is a waveform diagram of the driving voltage and current of the stator winding and an operation waveform diagram of the inductance detection circuit. 4 and 5, the same or corresponding parts as those in FIG. 1 shown in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 21 denotes an OP amplifier. 22, 23, 2
4 is connected to the OP amplifier 21 and the inductance circuit 1
Reference numeral 29 denotes a resistor for setting the detection level, and reference numeral 29 denotes an inverter that outputs the output of the OP amplifier 21 after waveform shaping and signal inversion. A control circuit 32 detects the end of the regeneration period based on an input signal from the inductance detection circuit 16 and outputs a stator winding excitation signal.

Next, the operation will be described with reference to FIGS. FIG. 6A is a waveform diagram of a stator winding driving voltage, and FIG.
(B) is a stator winding inductance waveform diagram, and FIG.
FIG. 6 (d) is an inductance detection circuit input voltage waveform diagram, FIG. 6 (e) is an inductance detection circuit output voltage waveform diagram, and FIG. 6 (f) is a step function signal waveform diagram. is there.

The sensorless SR motor receives a pair of transistors 8a and 8b based on a stator winding excitation signal from the control circuit 18.
Is turned ON, and current is supplied from the bus voltage 10 to the stator winding. At this time, the drive voltage and the drive current of the stator winding 3 are shown in FIGS.
6C, the drive current flowing through the stator winding 3 has a regenerative period during which the regenerative current flows, and the detectable period is such that the stator winding is not driven. Time, which is a period during which the inductance changes as shown in FIG.

During the detectable period, the position of the rotor is detected by detecting a change in the inductance of the stator winding 3. First, when the output voltage of the step function signal generation circuit 17 is turned on, the transistor 14 is turned on. Is turned ON, and a step function voltage is applied to the stator winding 3 from the detection power supply 19. The voltage at the time of transient response generated in the stator winding 3 by this step function voltage is input to the inductance circuit 16. This input voltage is shown in FIG.

The detection level of the inductance detection circuit 16 is set to a value Vs corresponding to the rotor position, and when the input signal is higher than the detection level, the output of the OP amplifier 21 becomes L
(Low-volt), and H (Hig)
h-volt). This signal is subjected to waveform shaping and signal inversion by the inverter 29, and the rotation position detection circuit 15
And output to the control circuit 18.

The detection level Vs needs to be a level for detecting the end of the regenerative period. It is sufficient to detect that the voltage of the regenerative current has reached a certain level or less. Does not flow, diode 9
Set to a voltage at which a is turned off. That is, the voltage may be set to a value higher than the voltage drop when the diode 9a is turned on.

The output voltage of the inductance detecting circuit 16 has a rising edge when the input voltage becomes Vs as shown in FIG. The control circuit 32 detects the rise of the output voltage, determines the end of the regeneration period, and transmits a transmittable signal for causing the step function signal generation circuit 17 to transmit a step function signal. Then, the step function signal generation circuit 17 outputs a step function signal as shown in FIG.

Next, the rotational position detecting circuit 15 detects the rotor position by detecting that the output voltage of the inductance detecting circuit 16 has become L after the control circuit 32 detects the end of the regeneration period.

As described above, if the position of the rotor corresponding to the value higher than the ON voltage of the diode 9a is set to the detection level, the influence on the regenerative current (regenerative period ), And the position of the rotor can be detected with high reliability without changing the characteristics of the SR motor.

Embodiment 3 Since the rotor position detecting device of the sensorless SR motor according to the present embodiment has the same configuration as that of FIG. 3 shown in the second embodiment and operates differently, the operation will be described. FIG. 7 is an operation waveform diagram. FIG.
(A), (b), and (c) show an example of the drive voltage pattern of the SR motor. FIG. 7 (a) is a U-phase stator winding drive voltage waveform diagram, and FIG. FIG. 7C is a V-phase stator winding driving voltage waveform diagram, and FIG. 7C is a W-phase stator winding driving voltage waveform diagram. 7 (d), (e) and (f) show the operation of the present embodiment. FIG. 7 (d) is a U-phase stator drive current waveform diagram, and FIG. 7F is a waveform diagram of the stator winding inductance, and FIG. 7F is a waveform diagram of the step function signal.

As shown in FIGS. 7A, 7B, and 7C, when the V-phase stator winding driving voltage is turned on while the U-phase stator winding driving voltage is turned on, The U-phase stator winding drive voltage is turned off. Further, when the W-phase stator winding drive voltage is turned ON, the V-phase stator winding drive voltage becomes OF
F. Thus, the SR motor rotates the rotor by sequentially turning on the stator winding drive voltage.

In the SR motor, a torque for rotating the rotor is generated by applying a drive voltage to the stator winding while the inductance of the stator winding is increasing. Also, if a driving voltage is applied during a period in which the inductance of the stator winding decreases while the rotor is rotating, a braking force acts on the stator winding. When a drive voltage is applied to the stator winding, a time lag occurs between the application of the drive voltage and the flow of a predetermined current due to the inductance of the stator winding. In order to secure a drive current at a predetermined position, the drive current is usually applied earlier.

As shown in FIG. 7D, there is a regenerative period from when the drive voltage is turned off to when the current is reduced to 0. In this period, the magnetic energy accumulated in the stator winding 3 is regenerated. Therefore, a regenerative current flows through the stator winding. If this regenerative current flows until the stator winding inductance is reduced, the rotor will be braked. Therefore, the regenerative current must be reduced to zero before the stator winding inductance decreases. The driving voltage is turned off at the moment. In the figure, the detectable period is when the stator winding is not driven, and the stator winding 3
This is a period during which the inductance of the changes.

Next, a U-phase stator winding will be described to simplify the operation in the present embodiment. The regenerative period after the U-phase stator winding drive voltage is turned off is normally set to zero before the U-phase stator winding inductance starts to decrease. This is shown in FIG.
As can be seen from (c) and (d), the operation is completed during the ON period (t1 to t3) of the V-phase stator winding drive voltage that is being driven next. Further, when the W-phase stator winding driving voltage to be turned on next is ON (t3 to t5), it is understood that the regenerative current is 0.

When the W-phase stator winding drive voltage is ON (t3 to t5), the U-phase stator winding inductance is minimized as shown in FIG. 7 (e).
As described above, in order to turn ON early, as shown in FIG.
There is a detectable period (t3 to t4) during the phase driving, and a change in the U-phase stator winding inductance can be sufficiently detected.

As described above, in order to detect the U-phase stator winding inductance, the timing of outputting the step function signal from the step function signal generating circuit 17 while avoiding the regenerative period is as shown in FIG. Applied next to
It can be seen that the operation should be performed during the period in which the phase stator winding drive voltage is ON (t3 to t5). Accordingly, the control circuit 32 shuts off the drive voltage applied to the stator winding, and then, when the drive voltage is applied to the stator winding to which the drive voltage is applied second, the step function signal generation circuit 17 to supply a step function voltage to each phase sequentially,
The position of the rotor is detected from the response signal of the step signal.

As described above, even if the end of the regenerative period is not detected, the effect on the regenerative current (extending the regenerative period) is avoided, the characteristics of the SR motor are not changed, the reliability is high, and the position of the rotor is high. Can be detected.

In the first and second embodiments, the inductance detecting circuit 16 detects the voltage at the transient response generated in the stator winding 3 by the step function voltage. Good.

[0059]

Since the present invention is configured as described above, it has the following effects.

The rotor position detecting device of the sensorless SR motor according to the present invention generates the step function signal after the regenerative period in which the regenerative current flows when the drive voltage applied to the stator winding is cut off. A step function signal generating circuit, which is connected between a power supply and the stator winding,
A resistor for determining a time constant at the time of transient response, a voltage applied from the power supply as a step function voltage based on the step function signal, a switch applied to the stator winding and the resistor, and the step function voltage An inductance detection circuit for detecting a voltage or a current at the time of a transient response generated in the stator winding and the resistance, and a detection voltage or a detection current detected by the inductance detection circuit and a position of the rotor salient pole. A rotation position detection circuit that detects the position of the rotor salient pole based on a predetermined voltage or current, so that the stator can be configured by a simple circuit without using a rotation position detection sensor. The position of the rotor can be detected without affecting the regenerative current generated in the winding.

Further, when the drive voltage applied to the stator winding is cut off, a regeneration period end detection circuit for detecting the end of a regeneration period in which a regenerative current flows, and an output signal from the regeneration period end detection circuit. A step function signal generating circuit that generates a step function signal, and a resistor that is connected between a power supply and the stator winding and determines a time constant during a transient response;
A switch applied to the stator winding and the resistor as a step function voltage based on the voltage applied from the power supply based on the step function signal, and a voltage generated in the stator winding and the resistor by the step function voltage. Based on an inductance detection circuit that detects a voltage or a current at the time of a transient response, based on a detection voltage or a detection current detected by the inductance detection circuit and a voltage or a current that is predetermined according to the position of the rotor salient pole. And a rotation position detection circuit for detecting the position of the rotor salient pole, so that the characteristics of the SR motor can be reduced by using a simple circuit without using a rotation position detection sensor and avoiding the influence on the regenerative current. Without changing, the position of the rotor can be detected with high reliability.

Further, a step function signal generating circuit for generating a step function signal, a resistor connected between the power supply and the stator winding and for determining a time constant at the time of transient response, and a voltage applied from the power supply, A switch applied to the stator winding and the resistor as a step function voltage based on a step function signal, and a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage is detected. An inductance detection circuit that compares a regenerative voltage or a current generated when the drive voltage applied to the stator winding is cut off with a predetermined level and outputs a detection signal; Based on the detection signal output by and the value of the voltage or current predetermined corresponding to the position of the rotor salient pole, A rotation position detection circuit that detects the position of the trochanter salient pole, and a control circuit that determines the end of a regeneration period of the regenerative voltage or current based on an output signal from the inductance detection circuit and drives the step function signal generation circuit. , The reliability and the position of the rotor can be detected with high reliability without changing the characteristics of the SR motor by avoiding the influence on the regenerative current and using a simple circuit with few constituent means.

Further, a step function signal generating circuit for generating a step function signal, a resistor connected between the power supply and the stator winding and for determining a time constant during transient response, and a voltage applied from the power supply, A switch applied to the stator winding and the resistor as a step function voltage based on a step function signal, and a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage is detected. Detecting the position of the rotor salient pole based on a detection signal output by the inductance detecting circuit and a voltage or current value determined in advance corresponding to the position of the rotor salient pole. And a drive voltage applied to the stator winding to which a second drive voltage is applied after the drive voltage applied to the stator winding is cut off. And a control circuit for driving the step function signal generation circuit when is applied, without detecting the end of the regenerative period, avoiding the influence on the regenerative current and without changing the characteristics of the SR motor. It has high reliability and can detect the position of the rotor.

The method of detecting the rotor position of the sensorless SR motor is such that when the drive voltage applied to the stator winding is cut off, the regenerative period in which the regenerative current flows ends.
Generating a step function signal, applying a voltage applied from a power supply as a step function voltage based on the step function signal to the stator winding via a resistor that determines a time constant during a transient response, The position of the rotor salient pole based on a voltage or current at the time of transient response generated in the stator winding and the resistor by a voltage and a voltage or current predetermined corresponding to the position of the rotor salient pole. Therefore, the position of the rotor can be detected by using a simple circuit without using the rotational position detection sensor and avoiding the influence on the regenerative current generated in the stator winding.

After the drive voltage applied to the stator winding is cut off, a step function signal is generated when the drive voltage is applied to the stator winding to which the drive voltage is applied second. As a step function voltage based on the step function signal, the voltage applied from the power supply is applied to the stator winding via a resistor that determines a time constant during a transient response,
Based on a voltage or current at the time of transient response generated in the stator winding and the resistor by the step function voltage and a voltage or current predetermined in accordance with the position of the rotor salient pole, the rotor salient Since the position of the pole is detected, even if the end of the regenerative period is not detected, the reliability is high without changing the characteristics of the SR motor by avoiding the effect on the regenerative current.
The position of the rotor can be detected.

[Brief description of the drawings]

FIG. 1 is a sensorless SR according to a first embodiment of the present invention;
FIG. 3 is a configuration diagram of a drive circuit of a sensorless SR motor including a motor rotor position detection device.

FIG. 2 is an operation waveform diagram for explaining a relationship between a regeneration period based on a driving voltage of a stator winding and a step signal.

FIG. 3 is a sensorless SR according to the first embodiment of the present invention;
FIG. 5 is a diagram illustrating operation waveforms of the motor rotor position detection device.

FIG. 4 is a sensorless SR according to a second embodiment of the present invention;
FIG. 3 is a configuration diagram of a drive circuit of a sensorless SR motor including a motor rotor position detection device.

FIG. 5 is a sensorless SR according to a second embodiment of the present invention;
FIG. 3 is a diagram illustrating an inductance detection circuit of the motor rotor position detection device.

FIG. 6 is a sensorless SR according to a second embodiment of the present invention.
FIG. 5 is a diagram illustrating operation waveforms of the motor rotor position detection device.

FIG. 7 is a sensorless SR according to a third embodiment of the present invention.
FIG. 5 is a diagram illustrating operation waveforms of the motor rotor position detection device.

FIG. 8 is a configuration diagram of a conventional general SR motor and its driving circuit.

FIG. 9 is a diagram showing a positional relationship between a stator and a rotor of a conventional general SR motor.

FIG. 10 is a diagram showing a change in inductance of a stator winding of a conventional general SR motor.

[Explanation of symbols]

3 Stator winding, 8a, 8b, 14 transistor, 9
a, 9b diode, 13 resistor, 15 rotation position detection circuit, 16 inductance detection circuit, 17 step function signal generation circuit, 18, 32 control circuit, 20 detection power supply, 25 rotor position detection device, 31 regeneration period end detection circuit .

Claims (6)

[Claims] 1. A step function signal generating circuit for generating a step function signal after a regenerative period in which a regenerative current flows when a drive voltage applied to a stator winding is cut off, a power supply and the stator. A resistor connected between the windings and determining a time constant during a transient response; and applying a voltage applied from the power supply to the stator winding and the resistor as a step function voltage based on the step function signal. A switch; an inductance detection circuit for detecting a voltage or a current at the time of a transient response generated in the stator winding and the resistance by the step function voltage; a detection voltage or a detection current detected by the inductance detection circuit; A rotation position detection circuit for detecting the position of the rotor salient pole based on a voltage or current predetermined in accordance with the position of the salient pole; Sensorless Switched reluctance motor rotor position detecting device characterized by comprising a. 2. A regenerating period end detecting circuit for detecting an end of a regenerating period in which a regenerative current flows when a driving voltage applied to a stator winding is cut off, and an output signal from the regenerating period end detecting circuit. A step function signal generating circuit for generating a step function signal, a resistor connected between a power supply and the stator winding and determining a time constant at the time of transient response, and a voltage applied from the power supply to the step function signal. A switch to be applied to the stator winding and the resistor as a step function voltage based on: and an inductance detection for detecting a voltage or current at the time of a transient response generated in the stator winding and the resistor by the step function voltage. Circuit, and a detection voltage or current detected by the inductance detection circuit and a predetermined voltage corresponding to the position of the rotor salient pole. Others based on the current, rotor position detecting apparatus of sensorless switched reluctance motor for the rotational position detecting circuit, comprising the detecting the position of the rotor salient poles. 3. A step function signal generating circuit for generating a step function signal, a resistor connected between a power supply and a stator winding, the resistor determining a time constant during a transient response, and a voltage applied from the power supply. A switch that is applied to the stator winding and the resistor as a step function voltage based on a step function signal; and detects a voltage or current at the time of a transient response generated in the stator winding and the resistor by the step function voltage. An inductance detection circuit that compares a regenerative voltage or current generated when the drive voltage applied to the stator winding is cut off with a predetermined level and outputs a detection signal; On the basis of a detection signal output by the controller and a voltage or current value predetermined in accordance with the position of the rotor salient pole. A rotation position detection circuit that detects the position of the child salient pole, a control circuit that determines the end of the regeneration period of the regenerative voltage or current based on an output signal from the inductance detection circuit, and drives the step function signal generation circuit; A rotor position detecting device for a sensorless switched reluctance motor, comprising: 4. A step function signal generating circuit for generating a step function signal, a resistor connected between a power supply and a stator winding and determining a time constant during transient response, and a voltage applied from the power supply. A switch that is applied to the stator winding and the resistor as a step function voltage based on a step function signal; and detects a voltage or current at the time of a transient response generated in the stator winding and the resistor by the step function voltage. An inductance detection circuit for detecting the position of the rotor salient pole based on a detection signal output by the inductance detection circuit and a voltage or current value predetermined in accordance with the position of the rotor salient pole. A rotational position detection circuit, and after shutting off the drive voltage applied to the stator winding,
A control circuit for driving the step function signal generation circuit when a drive voltage is applied to a stator winding to which a drive voltage is applied secondly, a sensorless switched reluctance motor comprising: Rotor position detector. 5. When a drive voltage applied to a stator winding is cut off, a step function signal is generated after a regenerative period in which a regenerative current flows, and a voltage applied from a power supply is applied to the step function signal. Is applied to the stator winding via a resistor that determines a time constant during transient response as a step function voltage based on the voltage during transient response generated in the stator winding and the resistor by the step function voltage. Or a rotor position of the sensorless switched reluctance motor, wherein the position of the rotor salient pole is detected based on a current and a voltage or current predetermined in accordance with the position of the rotor salient pole. Detection method. 6. A step function signal is generated when a drive voltage is applied to a stator winding to which a second drive voltage is applied after the drive voltage applied to the stator winding is cut off, A voltage applied from a power supply is applied as a step function voltage to the stator winding via a resistor that determines a time constant during a transient response as a step function voltage based on the step function signal. And detecting the position of the rotor salient pole based on a voltage or current at the time of a transient response generated in the resistor and a voltage or current predetermined in correspondence with the position of the rotor salient pole. Of detecting the rotor position of a sensorless switched reluctance motor.