JP6463183B2 - Motor control device and rotor position detection device - Google Patents

Description

  The present invention relates to a motor control device and a rotor position detection device that are used in a motor that has a saliency rotor and a stator with excitation windings and rotates by switching excitation current.

  One of the motors having a saliency rotor and a stator with exciting windings is a switched reluctance motor (hereinafter referred to as “SR motor”). Since the SR motor has a simple structure and does not require a permanent magnet, it is suitable for high speed operation and operation in a high temperature environment. The rotation principle of the SR motor is as follows. When the salient poles of the stator and the salient poles of the rotor are aligned while facing each other (the salient pole alignment state), the magnetic impedance is reduced and the inductance of the winding is maximized. Therefore, when an exciting current flows through the salient pole windings in a salient pole non-aligned state where magnetic flux does not easily flow, the rotor rotates so that the salient pole is aligned most easily. Therefore, by supplying an exciting current to a specific phase based on the position information of the rotor, a continuous magnetic attraction force can be generated and the rotor can be rotated.

  Conventionally, a rotor position detection sensor has been used as a means for obtaining rotor position information. However, such a sensor is not suitable for use under severe operating conditions such as high-speed operation and high-temperature environments described above.

  Therefore, in recent years, there has been proposed a motor control device that detects the rotational position of the rotor without using a position detection sensor and performs control for switching the supply destination of the excitation current based on the detection result. An example of such a motor control device is described in Patent Document 1 below. In the so-called salient pole alignment state in which the motor control device described in Patent Document 1 is used in an SR motor including a stator having three sets of phases, and the salient poles of the excitation phase face the salient poles of the rotor, Utilizing the fact that the induced voltages appearing in the other two sets of non-excitation phases become equal, the SR motor is driven by switching the excitation phase at the timing when this voltage difference becomes less than a predetermined value.

JP 2001-309691 A

  However, in many conventional motor control devices, the position is estimated based on the magnitude of voltage, current, and current ripple that supply driving power to the motor, and the influence of various noises such as spike noise of the motor supply current. As a result, there has been a problem that accurate position detection cannot be performed. That is, since accurate position detection cannot be performed, the switching timing of the excitation current cannot be optimized, and it has been difficult to achieve higher speed and higher rotation efficiency than ever.

  It is also known that when the SR motor is rotated at a high speed, a delay in current due to inductance causes a problem. In such a case, it is appropriate to advance the excitation phase, that is, to accelerate the switching timing of the excitation current. Therefore, it is more important to improve the accuracy of position detection in order to realize this.

  The present invention has been made in view of the above problems, and the object thereof is to detect the position of the rotor with high accuracy without being affected by noise included in the motor supply current. Motor control device and rotor position detection device that achieves higher speed and improved rotation efficiency, and does not require a complicated manufacturing process for the motor, and avoids a decrease in S / N. Is to provide.

  In order to achieve the object, the present invention takes the following means.

  That is, the motor control device of the present invention includes a plurality of salient poles constituting two or more phases and a stator in which excitation windings are provided in parallel on each salient pole, and a plurality of salient poles arranged in the stator. A motor control device for use in a motor that rotates a rotor by switching a phase to which an excitation current is applied, and uses the excitation winding of any phase as an induction winding. An induction circuit for injecting a specific voltage signal into the winding, and an excitation winding of the phase in which the injection circuit injects the voltage signal or a phase different from the phase is used as the induction winding, and is induced from the voltage signal. A detection circuit that detects an inductance from a current or an induced voltage, and a rotor position estimation unit that estimates a rotor position based on the inductance obtained by the detection circuit. At least one of the above is provided with a closed core that magnetically cancels a voltage change induced by the excitation current in the induction winding using the excitation winding, and through this core, the induction winding is connected to the induction winding. It is configured to inject a specific voltage signal or detect inductance from the induction winding, and to switch the phase for applying the excitation current based on the rotor position estimated by the rotor position estimation unit. It is characterized by.

  In this configuration, a voltage signal is injected from the injection circuit to the induction winding, and the detection circuit detects the inductance from the electromagnetic induction current or induced voltage that appears in the induction winding. Thus, the motor can be controlled while estimating the position of the rotor. In addition, since at least one of the detection circuit and the injection circuit is provided with a canceling unit, it is possible to cancel the voltage change induced by the excitation current required to rotate the rotor, thereby causing noise or the like due to the excitation current. Therefore, the disturbance of the waveform of the detection signal can be suppressed and the rotor position detection accuracy can be improved.

  Moreover, since the induction windings or excitation windings provided on the salient poles of each phase may be in parallel, for example, between the closed circuit connecting the neutral point and both ends by connecting the induction windings (excitation windings) in series. Compared with the case where the currents are canceled by a differential choke coil or the like, the excitation winding can be made thinner, and the motor can be manufactured easily and the cost can be reduced. Further, by using the core, a capacitor that separates the excitation current and the high-frequency signal component is not required, so that the differential element can be eliminated and the S / N ratio can be effectively improved.

  In this case, in order to easily configure the canceling unit, inductive windings that are arranged in parallel in each phase are provided in the core of the canceling unit, and a reverse magnetic flux is generated inside the core by the current flowing in each induction winding. It is desirable to engage with each other so as to generate the voltage signal generating means for generating the voltage signal or the inductance detecting means for detecting the inductance through the auxiliary winding.

  In order to make the injection circuit and the detection circuit common and to have a simple configuration, the injection circuit and the detection circuit are configured as a common injection detection circuit, and the voltage can be changed by switching a switch provided inside. It is effective to be configured to be selectively connected to voltage signal generating means for generating a signal or inductance detecting means for detecting the inductance.

  In addition, in order not to be affected even if the reference voltage supplied from the power source to the motor fluctuates, the rotor position is estimated only by comparing a plurality without obtaining the absolute value of the detected induced voltage. For this purpose, the detection circuit is configured to function in a phase different from that of the injection circuit, and the rotor position estimator is different in mutual inductance obtained from the induced voltage detected by each detection circuit or It is preferable that the configuration is such that the position of the rotor is estimated based on the magnitude relationship.

  For the same purpose, the detection circuit is configured to function in the same phase as the injection circuit, and the rotor position estimation unit is based on the difference or magnitude relationship of the self-inductance obtained from the current detected by each detection circuit. The rotor position may be estimated.

  According to the present invention described above, it is possible to detect the position of the rotor with high accuracy without being affected by noise included in the motor supply current while having a simple configuration. New and useful motor control apparatus and rotor that can improve the performance of the motor, and the solution for the motor does not require a complicated manufacturing process for the motor, and the S / N can be prevented from decreasing. A position detection device can be provided.

The schematic diagram which shows the cross section of SR motor which concerns on embodiment of this invention. The figure which shows the rotation principle of SR motor. The circuit diagram which shows the injection | pouring detection circuit which comprises the motor control apparatus which concerns on embodiment of this invention with an excitation circuit. 1 is a block diagram of a motor control device according to an embodiment of the present invention. The graph which shows the self-inductance of A phase and the mutual inductance of A phase, B, and C phase. The schematic diagram which shows one of the switching states of the excitation phase which concerns on embodiment of this invention. The schematic diagram which shows one of the switching states of the excitation phase different from FIG. The schematic diagram which shows one of the switching states of the excitation phase different from FIG.6 and FIG.7. The graph which shows the self-inductance of A phase which concerns on the modification of this invention, B phase, and C phase. The circuit diagram which shows the injection | pouring detection circuit which comprises the motor control apparatus which concerns on the modification with an excitation circuit. The figure which shows an example of the interference prevention in the injection | pouring detection circuit using a self-inductance. The figure which shows the other example of interference prevention in the injection | pouring detection circuit using a self-inductance.

  Hereinafter, a motor control device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a simplified diagram showing a configuration of an SR motor provided with a motor control device of the present invention. An SR motor (switched reluctance motor) 10 shown in FIG. 1 includes a stator 12 having six salient poles 11 projecting from an inner wall surface, and a rotor having four salient poles 13 rotating inside the stator 12. 14, the salient poles 11 of the stator 12 are installed at equal intervals every 60 degrees, and the salient poles 13 of the rotor 14 are installed at equal intervals every 90 degrees. Excitation windings 15a and 15a, 15b and 15b, and 15c and 15c are wound around the salient poles 11a and 11a, 11b and 11b, and 11c and 11c of the stator 12, respectively. A pair of salient poles 11a and 11a wound with 15a is A phase, a pair of salient poles 11b and 11b around which excitation windings 15b and 15b are wound is B phase, and excitation windings 15c and 15c are wound. A three-phase stator 12 having a salient pole pair 11c, 11c as a C phase is configured. An excitation circuit 28 (see FIG. 3) is connected to each of the excitation windings 15a to 15c so that an excitation voltage can be selectively applied to any of the A to C phases.

  Excitation windings 15a and 15a, 15b and 15b, and 15c and 15 forming a pair of salient poles are connected in parallel to the excitation circuit 28, respectively. Specifically, in the pair of power supply paths from the excitation circuit 28, the excitation windings 15a and 15a, 15b and 15b, and 15c and 15c that are paired before the first node N1 and the second node N2, respectively. Are connected in parallel.

  Here, the principle of rotation of the SR motor 10 will be described with reference to FIG. FIG. 2A shows the position of the rotor 14 in a salient pole non-aligned state in which the salient poles 11a to 11c and 13a to 13b of the stator 12 and the rotor 14 are not opposed to each other and the magnetic flux hardly flows. Then, the exciting winding 15a of the stator 12, that is, the A phase is excited. At this time, torque is generated in the rotor 14 so that the salient pole alignment state in which the magnetic flux flows most easily, that is, the salient pole 11a and the salient pole 13a of the rotor 14 are aligned, and the rotor 14 rotates. Then, when the phase to be excited is switched to the B phase at the timing at which the rotor 14 is rotated until the salient pole alignment state shown in FIG. 2B is reached, the salient pole 11b of the stator 12 and the salient pole 13b of the rotor 14 are aligned. Torque is generated. Thereafter, when the phase to be excited is switched to the C phase at the timing when the salient pole 11b of the stator 12 and the salient pole 13b of the rotor 14 are aligned, the salient pole 11c of the stator 12 and the salient pole 13a of the rotor 14 are now aligned. Torque is generated. Thus, by switching the excitation phase based on the position of the rotor 14, torque due to continuous magnetic attraction force is generated, and the SR motor 10 rotates.

  Next, FIG. 3 is a circuit diagram of the injection detection circuit 22 constituting the motor control device according to the present embodiment. The circuit shown in this figure is an injection detection circuit 22 that is used for both injection and detection of a high-frequency signal as a specific voltage signal, and includes induction windings 15x and 15y, and a closed core made of a magnetic material. A toroidal core 18 a, high frequency generation means 19, voltage detection means 20, and a switch 21 are included.

  The induction windings 15x and 15y constituting the single injection detection circuit 22 are also used as the excitation windings 15a (15b and 15c) and 15a (15b and 15c) (see FIG. 1) constituting one phase. Therefore, a simpler configuration is realized.

  Since the induction windings 15x and 15y also use the induction windings 15a and 15a {(15b, 15), (15c, 15c)}, the first and second nodes in the power supply path Are connected in parallel.

  A canceling unit 18 using a toroidal core 18a is provided between one end of each of the pair of excitation windings 15a and 15a (induction windings 15x and 15y) in the A phase and the second node N2, and the B phase Similarly, the C phase is provided with a canceling portion 18 using a toroidal core 18a. The A-phase canceling unit 18 engages a pair of excitation windings 15a and 15a (induction windings 15x and 15y) in the opposite direction with respect to the toroidal core 18a. Specifically, one excitation winding 15a (induction winding 15x) enters from one side in the axial direction of the toroidal core 18a and exits to the other, and the other excitation winding 15a (induction winding 15y). ) Is inserted through the other of the toroidal core 18a in the axial direction so as to come out from the other. The same applies to the B phase and the C phase.

  An auxiliary winding 18b is wound around the toroidal core 18a, and a high-frequency signal injected from the high-frequency generating means 19 is injected into the induction windings 15x and 15y via a magnetic flux generated in the toroidal core 18a. Alternatively, the induced voltage appearing in the induction windings 15x and 15y is detected by the voltage detecting means 20 which is an inductance detecting means via a magnetic flux generated in the toroidal core.

  The three injection detection circuits 22 are connected to the A phase, the B phase, and the C phase, respectively. Among the three phases, the excited phase is the injection circuit 23, and the remaining two non-excited phases are the detection circuit 24. When the switch 21 is operated, either the injection circuit 23 or the detection circuit 24 is switched.

  FIG. 4 shows a block diagram of the motor control device according to the embodiment of the present invention. The rotor position estimation unit 25 estimates the rotor position based on the detection voltage detected by any two of the A-phase injection detection circuit 22a, the B-phase injection detection circuit 22b, and the C-phase injection detection circuit 22c. 14 (see FIG. 2) transmits a switching signal to the injection detection switching unit 27 and the excitation phase switching unit 26 at the timing when the salient pole alignment state is reached. The injection detection switching unit 27 receives the switching signal, operates the switch 21 (see FIG. 3) of the injection detection circuit 22, and selects and switches one of the functions of the injection circuit 23 and the detection circuit 24. The excitation phase switching unit 26 receives the switching signal and switches the phase to which the excitation voltage is applied from the excitation circuit 28.

  And in this embodiment, it connects with the injection | pouring circuit 23 so that the phase by which a high frequency signal is inject | poured and the phase to be excited become the same (refer FIG. 6). The high frequency generation means 19 generates a high frequency signal having a frequency sufficiently higher than the excitation current.

  Next, an operation when the above embodiment is adopted will be described.

  When the injection detection circuit 22 functions as the injection circuit 23, the high frequency signal generated by the high frequency generation means 19 generates a magnetic flux in the toroidal core 18a around which the auxiliary winding 18b is wound, and thereby the induction windings 15x, 15y. A high frequency signal is superimposed on each of the exciting windings 15a and 15b as indicated by an arrow V in the figure through a magnetic coupling portion between the magnetic core and the toroidal core 18a. On the contrary, when the injection detection circuit 22 functions as the detection circuit 24, the current induced in the induction windings 15x and 15y is toroidal as indicated by the arrow V (the solid line and the broken line are for alternating current). It is detected as an induced voltage by the voltage detection means 20 through a magnetic coupling part with the core 18a. The current of the induction winding 15x and the current of the induction winding 15y at the time of detection are inflow and outflow as shown by arrows V at the nodes N1 and N2, respectively. Is avoided or reduced. Similarly, the high-frequency signal at the time of injection is avoided or reduced by disappearing at the nodes N1 and N2 and passing through the excitation circuit 28.

  Therefore, the injected high frequency signal is supplied to the windings 15x and 15y without loss, and the induced voltage generated in the windings 15x and 15y is detected without loss.

  On the other hand, the excitation current I0 for driving the motor output from the excitation circuit 28 is the currents I1 and I2 in the excitation windings 15a and 15a (15b and 15b, 15c and 15c) connected in parallel before the nodes N1 and N2, respectively. Become. By aligning the characteristics of the two exciting windings connected in parallel, I1 and I2 have substantially the same value.

  I1 and I2 generate magnetic fluxes φ1 and φ2 in the toroidal core 18a, respectively, but flow in opposite directions with respect to the toroidal core 18a, so φ1 and φ2 cancel each other. If I1 = I2, φ1 + φ2 = 0, and no magnetic flux is generated in the toroidal core 18a.

  For this reason, it is avoided that the excitation current affects the high-frequency signal injected from the high-frequency generation means 19, and the influence of the induced voltage detected by the voltage detection means 20 is also avoided.

  From the above, the injection circuit 23 and the detection circuit 24 reduce the influence of the excitation voltage supplied to the windings 15x and 15y and the noise caused by switching, while outputting high-frequency signals to the windings 15x and 15y. The voltage induced in the windings 15x and 15y can be taken out. That is, it is possible to suppress the influence on the high-frequency signal and the induced voltage due to spike noise generated due to switching of the excitation voltage or voltage fluctuation applied to the excitation voltage itself.

  Next, operation | movement of the rotor position estimation part 25 is demonstrated using FIGS.

  First, as shown in FIG. 6, a case where the phase A is excited is considered as state 1. At this time, the A phase circuit is connected to the high frequency generation means 19 by the switch 21, and the B phase and C phase circuits are connected to the voltage detection means 20 by the switch 21. That is, when the A phase is energized, the injection detection circuit 22 connected to the A phase operates as the injection circuit 23 and a high frequency signal is injected into the A phase, and the injection detection circuit connected to the B phase and the C phase. 22 operates as a detection circuit 24. At this time, whether the amplitudes of the high-frequency signals induced in the B phase and the C phase detected by the voltage detection unit 20 of the detection unit 24 coincide with each other by the comparator 29 constituting the rotor position estimation unit 25. Judgment is made. When the rotor 14 rotates and the two high-frequency signals coincide with each other, it is determined that the salient pole alignment state in which the A-phase salient pole 11a and the salient pole 13a or 13b of the rotor 14 are aligned is reached.

  This will be described in detail using the graph of FIG. 5 with reference to FIG. The graph of FIG. 5 shows the self-inductance La generated in the A-phase windings 15a and 15a, the mutual inductance Mab generated between the A-phase and the B-phase when the rotor angle is changed with a certain rotational position as a reference, and A An analysis example of the value of the mutual inductance Mac generated between the phase and the C phase is shown. The mutual inductances Mab and Mac are obtained on the basis of the detected induced voltage, and the change of the induced voltage and the mutual inductance detected by the voltage detecting means 20 is almost the same. Looking at the values on the graph where the rotor angle is around 90 degrees and on the straight line ls, the self-inductance value La of the A-phase windings 15a, 15a takes the maximum value, and the mutual inductance value Mab between the A-phase and the B-phase The mutual inductance value Mac between the A phase and the C phase is equal. This is due to the symmetry of the stator 12 and the rotor 14. By utilizing this property, it is determined that the salient pole alignment state is obtained when the high-frequency signals induced in the B phase and the C phase coincide with each other.

  Then, while the magnitudes of the amplitudes (x and y) of the voltages detected by the B-phase and C-phase voltage detection means 20 are different, the rotor position estimation unit 25 that has maintained the state 1 has the position of the rotor 14 When it is determined that the salient pole alignment state has been reached, that is, when x = y and z = 1 in FIG. 6, the phase to be excited is switched to the B phase (state 1 → state 2). The same applies when the B phase is excited (state 2 in FIG. 7) and when the C phase is excited (state 3 in FIG. 8), and the voltages detected in the two non-excited phases in each state. The amplitude changes to the next state at the same timing.

  Thereafter, while the B phase is energized, the A phase and the C phase operate as the detection circuit 24, and the comparator 29 constituting the rotor position estimation unit 25 operates in the same manner as when the A phase is energized. Estimate the position. In this way, by sequentially switching the exciting phase and the phase for injecting the high-frequency signal in order, the rotor 14 can be rotated while the position of the rotor 14 is estimated, and the motor can be driven sensorlessly. By configuring the rotor position to be estimated using the comparator 29 as described above, it is possible to detect the rotor position at a high speed while using a simple configuration that does not involve advanced calculations.

  As described above, the motor control device of the present embodiment includes the stator 12 having the plurality of salient poles 11 constituting two or more phases, and the respective salient poles 11 provided with the excitation windings 15a to 15c, and the plurality of salient poles. A motor control device for a motor 10 including a pole 13 and a rotor 14 disposed in the stator 12 and rotating the rotor 14 by switching a phase to which an excitation current is applied. An injection circuit 23 for injecting a specific voltage signal into the induction windings 15x and 15y using the lines 15a and 15a as induction windings 15x and 15y, and a phase in which the injection circuit 23 injects a voltage signal A detection circuit for detecting the inductance from the induced voltage induced by the voltage signal using the induction windings 15b, 15b, 15c and 15c of different phases as the induction windings 15x and 15y. 24 and a rotor position estimation unit 25 that estimates the position of the rotor 14 based on the inductance obtained by the detection circuit 24. The detection circuit 24 and the injection circuit 23 are provided with excitation windings 15a, 15b, and 15c. In the used induction windings 15x and 15y, a canceling unit 18 that magnetically cancels the voltage change induced by the excitation current is provided in the closed core 18a, and through the cancellation unit 18 to the induction windings 15x and 15y. Specific voltage signal injection or inductance detection from the induction windings 15x and 15y, and switching of the phase for applying the excitation current based on the rotor position estimated by the rotor position estimation unit 25. It is configured to do.

  With this configuration, a voltage signal is injected from the injection circuit 23 to the induction winding 15a, and the detection circuit 24 detects the inductance from the induced voltage caused by electromagnetic induction appearing in the induction windings 15b and 15c. Thus, it is possible to control the motor while estimating the position of the rotor 14 based on the detected inductance. In addition, since the canceling unit 18 is provided in the detection circuit 24 and the injection circuit 23, the influence of noise caused by the excitation current is canceled by canceling the voltage change induced by the excitation current required to rotate the rotor 14. This can reduce the disturbance of the voltage waveform and improve the rotor position detection accuracy, so that the excitation current can be switched at a more appropriate timing to increase the motor speed and the rotation efficiency. It can be realized.

  In addition, the induction windings 15x and 15y provided on the salient poles 11 of each phase, that is, the excitation windings 15a and 15a {(15b, 15b), (15c, 15c)} may be arranged in parallel. 15y, that is, exciting windings 15a, 15a {(15b, 15b), (15c, 15c)} are connected in series so that the current is canceled by a differential choke coil or the like between the closed circuit connecting the neutral point and both ends. Compared with the case where it comprises, etc., excitation winding 15a, 15b, 15c can be made thin, motor can be manufactured easily and cost reduction can be aimed at, such as enabling automatic winding. Furthermore, by using the core 18a, a capacitor that separates the excitation current and the high-frequency signal component is not necessary, so that the differential element can be eliminated and the S / N ratio can be effectively improved.

  In this case, inductive windings 15x and 15y that are parallel in each phase are applied to the core 18a of the canceling unit 18, and currents I1 and I2 that flow through the induction windings 15x and 15y are reversed in the core 18a. The cores 18a are engaged with each other so as to generate φ1 and φ2, and the voltage signal generating means 19 for generating a voltage signal through the auxiliary winding 18b and the voltage detecting means 20 for detecting the induced voltage are magnetically coupled to the core 18a. Therefore, the canceling unit 18 can be configured easily.

  In addition, the injection circuit 23 and the detection circuit 24 are configured as a common injection detection circuit 22, and by switching a switch 21 provided therein, a high frequency generation means 19 as a voltage generation means or an inductance detection By being configured to be selectively connected to the voltage detection means 20 for detecting the induced voltage, the injection circuit 23 and the detection circuit 24 can be made common and a simple configuration can be achieved. .

  Further, the detection circuit 24 is configured to function in a phase different from that of the injection circuit 23, and the comparator 29 constituting the rotor position estimation unit 25 is based on the induced voltage detected by each detection circuit 24, that is, based on the difference in mutual inductance. Since the position of the rotor 14 is estimated, the absolute value of the detected induced voltage is obtained so that the reference voltage supplied from the power source to the motor is not affected even if the reference voltage fluctuates. The rotor position can be estimated only by comparing a plurality.

  Furthermore, since a toroidal core 18a, which is generally used as a noise countermeasure, is used as a core, a core with a proven track record with little magnetic flux leakage is adopted and effectively adapted to the special purpose and application of the present invention. Can do.

  The specific configuration of each unit is not limited to the above-described embodiment.

  For example, although the mutual inductance is used as the characteristic to be measured for detecting the rotor position in the above embodiment, the self-inductance may be used.

  FIG. 9 shows an example of the self-inductance of each phase as viewed from the voltage signal generating means 19. In FIG. 4, the rotor is aligned with the A-phase stator at 0, 90, and 180 deg. At this time, the B-phase and C-phase self-inductances coincide. Similarly, when the rotor is aligned with the B-phase stator, the C-phase and A-phase self-inductances coincide with each other, and when the rotor is aligned with the C-phase stator, the A-phase and B-phase self-inductances coincide.

  Therefore, as shown in FIG. 10, the injection detection circuit 22 is connected in series with the voltage signal generation means 19 and the current detection means 120 as the inductance detection means so that the detection circuit 24 functions in the same phase as the injection circuit 23. Thus, the self-inductance can be measured from the current detected by the current detection means 120, and the rotor position estimation unit 25 can detect the difference in self-inductance obtained from each detection circuit 24 in two phases other than the excitation phase or The position of the rotor can be estimated based on the magnitude relationship. That is, the self-inductance L is calculated from the voltage V, current I, and frequency f of the signal to be injected.

L = V / (2 × π × f × I)
Such a self-inductance L is measured for each phase as shown in FIG. When the two-phase self-inductances coincide with each other, it is determined that the salient poles of the rotor 12 and the stator 12 of the phase not being measured are aligned, and if the measurement is switched, the same motor control as in the above embodiment is possible. .

  In this case, if a signal is injected into two phases in order to measure the two-phase self-inductance, the signal interferes inside the motor. Therefore, as shown in FIG. 11, the frequency of the signal injected from the voltage signal generating means 19 is changed to f1, f2, and f3 for each motor phase, and a bandpass filter BPF is provided in the current detection unit 120 for inductance detection. By configuring so as to extract only the signal component injected into the own phase, it is possible to remove the influence of signals of other phases.

  Further, even if the rotor position detection signal is time-divided and injected into the motor, signal interference can be avoided. FIG. 12 shows the circuit configuration. A switch 121 is provided at the end of the injection detection circuit 22, and by switching the switch 121, the phase for signal injection and inductance measurement is switched. For example, in the section of rotor positions 60 to 90 deg shown in FIG. 9, interference can be avoided by injecting signals alternately into the B phase and the C phase and measuring the self-inductance.

  Examples of modifications other than the above include the following.

  For example, the motor control device of the present embodiment is applied to a switched reluctance motor that does not have a magnet in the rotor 14. However, if the rotor 14 has a salient pole, the motor control device is applied to another motor including the rotor 14 having a magnet. It is also possible.

  In the above-described embodiment, the configuration in which the phase to be excited is synchronized with the phase in which the high-frequency signal is injected has been described, but the switching timing of the high-frequency signal injection / detection and the switching timing of the excitation phase to the windings 15a to 15c are asynchronous. It is also possible to take the configuration described in (1). Therefore, even when the excitation phase is advanced with respect to the delay of the current change due to the inductance of the motor during high-speed rotation, the phase advance control can be easily performed.

  Further, by increasing the frequency of the high-frequency signal to be injected, it is possible to drive the sensorlessly up to ultra high-speed rotation.

  Further, the motor control device described in the present embodiment may be configured such that PWM (Pulse Width Modulation) control can be further performed. Specifically, the excitation circuit 28 generates a rectangular pulsed excitation voltage according to the PWM signal, and the rotor speed can be adjusted by changing the duty ratio of the PWM signal.

  Further, the voltage signal injected from the injection circuit 23 is a high frequency signal. However, as long as sufficient resolution can be obtained with respect to the rotational speed of the rotor, it is possible to use a voltage signal of another form in addition to the high frequency signal. It is.

  Further, in the case where the injection circuit 23 and the detection circuit 24 are provided independently, the accuracy of the high-frequency signal or detection signal to be injected can be increased as long as a canceling unit is provided on either one, and the above is similar. An effect can be obtained.

  Further, in the above embodiment, the comparator 29 is introduced as the position estimation unit 21 and the excitation phase is switched by the difference in the detection voltage in the non-excitation phase. By detecting this, it is possible not only to determine the salient pole alignment state but also to detect that the rotor is positioned at a specific angle. By doing so, it is possible to perform phase advance control corresponding to the delay of magnetic flux generation and to further increase the rotational efficiency of the motor.

  Further, the portion excluding the excitation phase switching unit 26 and the excitation circuit 28 from the motor control device described above can be used as a position detection device for the rotor 14 similar to a resolver, an encoder, or the like. Also in this case, like the motor control device, the injection circuit 23 injects a voltage signal into the induction winding 15a, and the detection circuit 24 converts the inductance due to electromagnetic induction appearing in the mutual induction windings 15b and 15c to the induced voltage or By detecting through the current, the position of the rotor 14 can be estimated. In addition, since the canceling unit 18 using the core 18a is provided in the detection circuit 24 and the injection circuit 23, the voltage change induced by the excitation current required to rotate the rotor 14 can be canceled to obtain the excitation current. The influence of noise caused by the noise can be reduced, and the disturbance of the voltage waveform can be suppressed. The rotor position detection accuracy can be improved while avoiding the decrease of S / N ratio. It is possible to use a roll that is easy to manufacture and inexpensive.

  Other configurations can be variously modified without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Switch reluctance motor 11a, 11b, 11c ... Stator pole of stator 12 ... Stator 13 ... Salient pole of rotor 14 ... Rotor 15a, 15b, 15c ... Excitation winding 15x, 15y ... Mutual induction winding 18 ... Counterbalance part 18a ... Toroidal core 18b ... Auxiliary winding 19 ... Voltage signal generating means (high frequency generating means)
20: Inductance detection means (voltage detection means)
DESCRIPTION OF SYMBOLS 21 ... Switch 22 ... Injection detection circuit 23 ... Injection circuit 24 ... Detection circuit 25 ... Rotor position estimation part 120 ... Inductance detection means (current detection means)
L ... Self inductance M ... Mutual inductance

Claims (5)

A stator having a plurality of salient poles constituting two or more phases, each having a salient pole provided in parallel with each of the salient poles, and a rotor having a plurality of salient poles arranged in the stator, A motor control device used for a motor that rotates a rotor by switching a phase to be applied,
An injection circuit that injects a specific voltage signal into the induction winding using an excitation winding of any phase as an induction winding, and a phase in which the injection circuit injects a voltage signal or a phase thereof is different A detection circuit for detecting an inductance from a current or an induced voltage induced from the voltage signal using a phase excitation winding as an induction winding, and a position of the rotor based on the inductance obtained by the detection circuit A rotor position estimation unit for estimating
At least one of the detection circuit and the injection circuit is provided with a canceling unit that magnetically cancels the voltage change induced by the exciting current in the induction winding using the exciting winding in the closed core,
It is configured to inject a specific voltage signal into the induction winding or detect the inductance from the induction winding through this canceling unit,
A motor control device characterized in that a phase for applying an excitation current is switched based on a rotor position estimated by the rotor position estimation unit.   Inductive windings in parallel in each phase are engaged with the core of the canceling unit so as to generate a reverse magnetic flux in the core by the current flowing through each induction winding, and the auxiliary windings are connected to the core. The motor control device according to claim 1, wherein a voltage signal generating means for generating the voltage signal or an inductance detecting means for detecting an inductance is magnetically coupled to each other.   The injection circuit and the detection circuit are configured as a common injection detection circuit, and are selected as a voltage signal generation unit that generates the voltage signal or an inductance detection unit that detects the inductance by switching an internal switch. The motor control device according to claim 1, wherein the motor control device is configured to be connected to each other.   The detection circuit is configured to function in a phase different from the injection circuit, and the rotor position estimation unit is based on a difference or magnitude relationship of mutual inductances obtained from induced voltages detected by the detection circuits. The motor control device according to claim 1, wherein the motor control device is configured to estimate a position of the rotor. The detection circuit is configured to function in the same phase as the injection circuit, and the rotor position estimation unit is configured based on the difference or magnitude relationship of the self-inductance obtained from the current detected by each detection circuit. The motor control device according to claim 1, wherein the motor control device is configured to estimate a position.

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