JP2011030385A - Motor drive and method of determining relative position of rotor equipped in motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform sensorless control in the low speed zone at a lower cost as compared with prior art. <P>SOLUTION: A first voltage, i.e., a phase voltage of the nonenergized phase of a motor winding, when a driving power is supplied to the motor winding of a pair of energized phases in a first direction, and a second voltage, i.e., a phase voltage of the nonenergized phase of a motor winding, when a driving power is supplied to the motor winding of a pair of energized phases in a second direction are detected (110, 114), and then the position of the rotor relative to the stator is determined based on a change in the relationship of magnitude of the first and second voltages (116). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor drive device and a method for determining a relative position of a rotor provided in a motor.

  Conventionally, as a sensorless control of a brushless motor, a method for detecting an induced voltage during driving and estimating a position is known (for example, see Patent Document 1). However, with the technology described in Patent Document 1, the induced voltage cannot be detected unless the motor speed is increased to some extent, and Patent Document 1 does not describe any sensorless control in the stop and low speed regions.

  Therefore, as a method for realizing this stop and low-speed sensorless control, a method for estimating the position from the winding inductance that changes depending on the rotor position has been proposed (for example, see Non-Patent Document 1).

Japanese Examined Patent Publication No. 58-025038

IEEJ Transaction D vol.126 No.3 “High-performance sensorless IPM motor control system by harmonic current injection”

  However, the technique described in Non-Patent Document 1 requires a highly accurate three-phase current detector (current sensor), and there is a problem that the cost increases.

  The present invention has been made to solve the above-described problems, and is sensorless control in a low speed region (for example, control including processing for determining the relative position of the rotor with respect to the stator) as compared with the prior art. It is an object of the present invention to provide a motor drive device and a method for determining the relative position of a rotor provided in the motor.

  In order to achieve the above object, a motor driving apparatus according to claim 1 is a stator having a plurality of phase motor windings each generating a magnetic field, and a magnetic field generated by each of the plurality of phase motor windings. A motor including a rotor that is rotationally driven by the first motor winding of a pair of energized layers to which driving power is supplied among the motor windings of the plurality of phases based on a relative position of the rotor to the stator; Drive power from a drive power supply means for supplying drive power to each motor winding is alternately supplied in a direction opposite to the first direction and a second direction that is opposite to the first direction. Drive power is supplied to the motor windings of the pair of energized phases in the first direction and control means for controlling the drive power supply means so as to rotate in a predetermined direction relative to the stator. A first voltage which is a phase voltage of a motor winding of a non-energized phase and a motor of the non-energized phase when driving power is supplied to the pair of energized phase motor windings in the second direction Detection means for detecting a second voltage, which is a phase voltage of the winding, and a relative position of the rotor with respect to the stator based on a change in the magnitude relationship between the first voltage and the second voltage And discriminating means.

  According to the first aspect of the present invention, the driving power is alternately supplied to the motor windings in the first direction and the second direction, and the motor windings of the pair of energized phases are driven in the first direction. The first voltage, which is the phase voltage of the motor winding of the non-conduction phase when power is supplied, and the non-conduction phase when drive power is supplied to the motor winding of the pair of conduction phases in the second direction The second voltage, which is the phase voltage of the motor windings, is detected. Then, the relative position of the rotor with respect to the stator is determined based on the change in the magnitude relationship between the first voltage and the second voltage. Therefore, according to the first aspect of the present invention, the relative position of the rotor with respect to the stator can be determined without using an expensive current sensor. That is, the relative position of the rotor with respect to the stator can be determined without cost as compared with the prior art.

  According to a second aspect of the present invention, there is provided the motor driving device according to the first aspect, wherein the control means is arranged in the first direction and the motor windings of the pair of energized layers. Driving power from the driving power supply means is alternately supplied in the second direction for a time corresponding to the predetermined relative position, and the rotor rotates in a predetermined direction relative to the stator. The drive power supply means is controlled to drive.

  According to a third aspect of the present invention, there is provided the motor driving device according to the second aspect, wherein the control means is configured such that, when the rotation of the rotor is stopped, the pair of energized phases. The driving power times in the first direction and the second direction supplied alternately to the motor windings are made the same. Thereby, even when the rotation of the rotor is stopped, the relative position of the rotor with respect to the stator can be detected by the first voltage and the second voltage in the non-energized phase.

  According to a fourth aspect of the present invention, there is provided the motor drive device according to any one of the first to third aspects, wherein the detection means is connected to the pair of energized phase motor windings. The first voltage is detected after a lapse of a predetermined period from the start of the driving power supply in the first direction, and the driving power supply in the second direction is applied to the pair of energized phase motor windings. The second voltage is detected after a lapse of a predetermined period from the start. As a result, the phase voltage of the non-energized phase motor winding with the stable voltage value is not the voltage of the non-energized phase motor winding immediately after the supply of drive power whose voltage value is not stabilized due to ringing. It can be detected as a voltage of 1 and a second voltage.

  In order to achieve the above object, a method for determining a relative position of a rotor provided in a motor according to a third aspect of the present invention includes a stator having a plurality of phases of motor windings each generating a magnetic field, and the plurality of phases. A pair of motor windings of the plurality of phases that are supplied with driving power based on the relative position of the rotor with respect to the stator of a rotor having a rotor that is rotationally driven by a magnetic field generated by each of the motor windings Drive from drive power supply means for supplying drive power to each motor winding in a first direction and a second direction opposite to the first direction to the motor windings of the energization layer The drive power supply means is controlled so that electric power is alternately supplied and the rotor is rotationally driven in a predetermined direction relative to the stator, and the motor windings of the pair of energized phases in the first direction. A first voltage that is a phase voltage of a motor winding in a non-energized phase when driving power is supplied to the motor, and a driving power supplied to the pair of energized phase motor windings in the second direction A second voltage, which is a phase voltage of the motor winding of the non-conduction phase, is detected, and based on the change in the magnitude relationship between the first voltage and the second voltage, the rotor relative to the stator This is a method for discriminating the correct position.

  According to the third aspect of the present invention, the relative position of the rotor with respect to the stator can be determined based on the same principle as that of the first aspect of the present invention as compared with the prior art without cost. it can.

It is a block diagram which shows the outline of a structure of the brushless motor drive device which concerns on embodiment of this invention. It is a figure which shows the magnetic flux amount of each armature winding of U phase, V phase, and W phase. It is a figure for demonstrating 120 degree | times electricity supply. It is a figure which shows the change of the inductance of an armature winding. It is a figure for demonstrating an example of the detection method of the inductance ratio in embodiment of this invention. It is a figure for demonstrating an example of the detection method of the inductance ratio in embodiment of this invention. It is a figure for demonstrating an example of the position signal in embodiment of this invention. It is a figure for demonstrating the flow of the process in embodiment of this invention. It is a figure for demonstrating an example of the voltage waveform of U phase, V phase, and W phase.

  Hereinafter, an example of an embodiment of a motor drive device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a brushless motor driving apparatus according to an embodiment of the present invention.

  In the brushless motor 12, U-phase, V-phase, and W-phase armature windings ((stator) in FIG. 1, the phase type (U, V, W) is indicated on the short diameter frame) is star-connected (Y-connected). The three-phase armature winding and the rotor (rotor) are included. The phases U, V, and W of the three-phase armature windings are arranged at a pitch of 120 °, and switching that constitutes a pulse width modulation (PWM) type inverter of the brushless motor driving device 10. Connected to the output terminal of the element group 14, power is supplied from the switching element group 14 to the terminal A via the conductor A ′, to the terminal B via the conductor B ′, and to the terminal C via the conductor C ′.

  The switching element group 14 is connected to a DC power source (battery) 16 and a capacitor C is connected in parallel. The three-phase armature winding is energized and switched to each phase of the three-phase armature winding by a transistor of the switching element group 14 at a predetermined timing, thereby forming a rotating magnetic field.

  Three pairs (six in total) of transistors TR1 to TR6 as switching elements constituting the switching element group 14 are connected in a three-phase bridge, and a diode D is connected in parallel to each transistor.

  Further, the brushless motor driving apparatus 10 is provided with a controller 18 for controlling the driving of the brushless motor 12 and an observer 20 for determining (detecting) the relative position of the rotor with respect to the stator of the brushless motor 12.

  The controller 18 is connected to each of the transistors TR1 to TR6 connected in a three-phase bridge, and is also connected to an observer 20. The position of the rotor of the brushless motor 12 determined by the observer 20 (with respect to the armature winding). The drive of the brushless motor 12 is controlled by controlling each transistor according to the relative position (angle) of the rotor.

  The observer 20 is connected to the armature windings (terminals A, B, and C) of each phase of the brushless motor 12, and converts analog data indicating the voltages at the terminals A, B, and C into digital data. The voltage of the armature winding (terminals A, B, C) is detected. Then, by detecting the voltage of the armature winding, the relative position of the rotor with respect to the three-phase armature winding is determined, and the determination result is output to the controller 18.

  By the way, since the brushless motor switches energization to each phase of the three-phase armature winding in synchronization with the magnetic pole position of the rotor, it is necessary to determine the position of the rotor. Therefore, in the present embodiment, when determining the position of the rotor, the relative position between the three-phase armature winding and the rotor is determined without using an expensive current sensor.

  Here, a method for determining the relative position of the rotor with respect to the stator in the brushless motor driving apparatus 10 according to the present embodiment will be described. In the present embodiment, in the driving method in which the three-phase brushless motor 12 is energized 120 degrees, two phases (energized phases) to which a 120-degree energization voltage is applied are applied by complementary energization (that is, Driving power for supplying driving power to each motor winding in the first direction and the second direction opposite to the first direction to the armature winding that is the motor winding of the energization layer Driving power is alternately supplied from a DC power source 16 as supply means, whereby the rotor of the brushless motor 12 is rotationally driven in a predetermined direction relative to the stator. A non-energized phase to which no voltage is applied is in an open state (a state in which the DC power supply 16 is not electrically connected), and the terminal voltage of the armature winding of the non-energized phase in the open state is detected, whereby the rotor with respect to the stator The relative position of is determined.

  When the amount of magnetic flux is as shown in FIG. 2 in the U-phase, V-phase, and W-phase armature windings, as shown in FIG. 3, the 120-degree energization has a 90-degree phase difference from the magnetic flux. Made. That is, as shown in FIG. 3, the controller 18 controls on / off of the transistors TR1 to TR6 so that voltages are applied to the U-phase, V-phase, and W-phase armature windings.

  Incidentally, the inductance of each armature winding changes as shown in FIG. 4 depending on the amount of magnetic flux of the brushless motor 12. As shown in the figure, when the absolute amount of magnetic flux increases, the inductance decreases, and when the absolute amount of magnetic flux decreases, the inductance increases. In this embodiment, in order to detect the inductance that changes depending on the relative position of the rotor, a voltage (pulse voltage) having an AC component is applied to a pair of armature windings of the energized phase, and the divided voltage value is used. Detect the inductance ratio.

  Here, an example of a method for detecting the inductance ratio will be described. For example, in a section of 150 to 210 degrees in electrical angle, the energized phase is a V-phase armature winding and a W-phase armature winding, and the non-energized phase is a U-phase armature winding. In this case, as shown in FIG. 5 and FIG. 6, the controller 18 puts the U-phase armature winding in an open state (no connection) and supplies a DC power to the V-phase armature winding (terminal B). Application of positive voltage of 16 and connection of negative terminal to W-phase armature winding (terminal C), application of positive voltage of DC power supply 16 to W-phase armature winding (terminal C) and V-phase The connection of the minus terminal to the armature winding (terminal B) is alternately repeated. The application time of each positive voltage in the case of repeating alternately is a value obtained in advance by an experiment for each section of a predetermined angle of 60 degrees so that the rotor appropriately rotates. Here, the section of 60 degrees means, for example, −30 degrees to 30 degrees, 30 degrees to 90 degrees, 90 degrees to 150 degrees, 150 degrees to 210 degrees, 210 degrees to 270 degrees, 270 degrees to 330 degrees ( -30 degrees). Accordingly, the motor windings (armature windings) of the pair of energization layers are provided with a first direction (for example, V phase to W phase) and a second direction (for example, W direction opposite to the first direction). The driving power from the DC power source 16 for supplying driving power to each motor winding is alternately supplied from the phase to the V phase), and the rotor is driven to rotate in a predetermined direction relative to the stator. In addition, when the rotor is stopped, the position detection is possible by the voltage of the non-energized phase even in the stopped state by applying each positive voltage repeatedly repeated for the same time. When the rotor starts to rotate, each plus voltage is alternately applied for an application time obtained in advance by experiments.

  In FIG. 5, the application time of the positive voltage of the DC power supply 16 is substantially the same between the V phase and the W phase in order to reduce the inter-winding voltage so that the brushless motor 12 is driven to rotate at a low speed. . As shown in the following formula (1), the motor rotation speed R is represented by the product of the motor rotation constant K and the voltage V.

  R = K × V Formula (1)

  At this time, for the U-phase armature winding (terminal A), the positive voltage of the DC power supply 16 is divided into the voltage division value of the winding inductance by the V-phase armature winding and the W-phase armature winding, A voltage obtained by adding the induced voltage appears. In FIG. 5A, a voltage is applied from the V phase to the W phase, and in FIG. 5B, a voltage is applied from the W phase to the V phase. At this time, the phase voltage U ′ of the U phase, which is a non-energized phase when a voltage is applied from the V phase to the W phase, can be detected according to the following equation (2).

  U-phase phase voltage U ′ = (plus voltage B of DC power supply 16) × (W-phase inductance) ÷ ((V-phase inductance) + (W-phase inductance)) + U-phase induced voltage (2)

  In addition, the phase voltage U ″ of the U phase, which is a non-conduction phase when voltage is applied from the W phase to the V phase, can be detected according to the following equation (3).

  U-phase phase voltage U ″ = (plus voltage B of DC power supply 16) × (V-phase inductance) ÷ ((V-phase inductance) + (W-phase inductance)) + U-phase induced voltage Equation (3)

  When detecting the U-phase voltage, as shown in FIG. 5C, analog data indicating the voltage at a position where the voltage is stable is converted into digital data, so that the armature winding (terminal A, The voltage B, C) may be detected. More specifically, for example, immediately after the voltage is applied, the U-phase voltage U is not stabilized by ringing. Therefore, the phase voltage U is detected at a position where the ringing is settled and the voltage is stabilized. Since this ringing period (time) is substantially determined by the motor, the phase voltage U may be detected after a predetermined period has elapsed after the positive voltage is applied.

  Since the phase voltage U ′ and the phase voltage U ″ are detected within the same carrier period, it can be considered that the rotor hardly rotates and is included in the phase voltage U ′ and the phase voltage U ″. It can be considered that the magnitudes of the induced voltages are the same. Therefore, as shown in the following equation (4), the value of ((phase voltage U ′) − (phase voltage U ″)) is calculated as a position signal that is a signal indicating the relative position of the rotor with respect to the stator. Thus, the influence of the induced voltage can be ignored.

  Position signal = ((phase voltage U ′) − (phase voltage U ″)) (4)

  Here, the value of the position signal in the section of 0 to 360 degrees in electrical angle is shown in FIG. It can be seen that the position signal of V-W crosses 0 in the 150-210 degree section where the voltage is applied between the V-phase and the W-phase while the U-phase is open. A position signal when the energized phases are the K phase and the L phase is referred to as a KL position signal. Since the zero cross of the position signal indicates that the magnitude relationship of the winding inductances of the V phase and the W phase is reversed, this zero cross is an accurate position detection (position determination) point. From this, accurate position information of an electrical angle of 180 degrees can be obtained in a section of 150 to 210 degrees. Based on the same principle, accurate position information can be obtained even in sections of 30 to 90 degrees, 90 to 150 degrees, 210 to 270 degrees, 270 to 330 degrees, and 330 to 30 degrees. In the present embodiment, examples of accurate position information include 60 degrees, 120 degrees, 240 degrees, 300 degrees, and 360 degrees, respectively. In this way, it is possible to determine an accurate position for every electrical angle of 60 degrees. Further, in 120-degree energization, if position information for every electrical angle of 60 degrees is determined, it can be energized appropriately.

  Next, operation | movement of the brushless motor drive device 10 of this Embodiment is demonstrated with reference to the flowchart of FIG.

  First, in step 100, it is determined whether or not the motor is stopped. If it is determined in step 100 that the motor is stopped, the relative position of the rotor with respect to the stator is detected in the next step 101 (relative position detection). In this step, the relative position of the rotor in a stopped state is detected using a conventionally known technique. Then, the process returns to step 100.

  If it is determined in step 100 that the motor is not stopped, it is determined in step 102 whether the motor rotation speed is low (for example, 1200 rpm or less). Determine.

  If it is determined in step 102 that the speed is not low, the induced voltage is detected in the next step 103, the relative position of the rotor to the stator is detected based on the induced voltage, and the motor is detected based on the detected relative position of the rotor. A conventionally well-known sensorless control for controlling the rotational drive is performed. Then, the process returns to step 102. If it is determined in step 102 that the speed is low, the process proceeds to the next step 106.

  In the next step 106, it is determined whether or not the relative position of the rotor with respect to the stator is in a range from 0 degrees to less than 30 degrees, from 150 degrees to less than 210 degrees, and from 330 degrees to 360 degrees.

  If it is determined in step 106 that the relative position of the rotor with respect to the stator is within the range of 0 ° to less than 30 °, 150 ° to less than 210 °, and 330 ° to 360 °, the next step Proceed to 108.

  In step 108, the U-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the V-phase armature winding (terminal B), and the W-phase armature winding is set. Connect the negative terminal to the line (terminal C). The positive voltage application time is a value obtained in advance by experiments every 60 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor. For example, the voltage waveforms of the U phase, V phase, and W phase when the relative position of the rotor is 180 to 210 degrees are as shown in FIG. 9A, and the U phase and V when the relative position of the rotor is 0 to 30 degrees. The voltage waveforms of the phase and the W phase are as shown in FIG. When the relative position of the rotor is 150 to 180 degrees, the magnitude relationship between the voltage application times of the V phase and the W phase is the same as that shown in FIG. 9A, and the magnitude relationship of the U phase voltage is as shown in FIG. Reverses that shown in

  In the next step 110, the U-phase voltage is detected.

  In step 112, the U-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the W-phase armature winding (terminal C), and the V-phase armature winding is set. Connect the negative terminal to the line (terminal B). The positive voltage application time is a value obtained in advance by experiments every 60 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor.

  In the next step 114, the U-phase voltage is detected and the process proceeds to step 116.

  In the first step 116, the U-phase voltage detected in step 110 and the U-phase voltage detected in step 114 are compared to determine the magnitude relationship.

  In the second and subsequent steps 116, first, the U-phase voltage detected in step 110 and the U-phase voltage detected in step 114 are compared to determine the magnitude relationship. Then, the magnitude relation determined in the previous step 116 is compared with the magnitude relation determined this time to determine whether the magnitude relation has changed. For example, in the previous magnitude relationship, the U-phase voltage detected in step 110 was greater than the U-phase voltage detected in step 114, whereas in the current magnitude relationship, the U-phase voltage was detected in step 114. If the U-phase voltage is greater than the U-phase voltage detected in step 110, it is determined that the magnitude relationship has changed.

  If it is determined in step 116 that the magnitude relationship has not changed, the process proceeds to step 108 described above. On the other hand, if it is determined in step 116 that the magnitude relationship has changed, the rotation speed of the brushless motor 12 is calculated in the next step 118. For example, in step 118, a value obtained by dividing 60 degrees by the time from when it is determined that the magnitude relationship has changed last time until it is determined that the magnitude relationship has changed this time is calculated as the rotation speed of the brushless motor 12. It may be. Then, the process proceeds to the next step 120. In step 120, since it is determined that the magnitude relationship has changed this time, a time indicated by a value obtained by dividing a predetermined electrical angle (for example, 30 degrees) by the rotation speed calculated in step 118 (hereinafter, this time is referred to as a standby time). Is determined). When it is determined in step 120 that the standby time has not elapsed since it was determined that the magnitude relationship has changed this time, the process returns to step 106. If it is determined in step 120 that the magnitude relationship has been changed this time and the standby time has elapsed, the process proceeds to the next step 122. This is because there is a phase difference of 30 degrees in electrical angle between the point where the magnitude relationship changes and the energization switching point, and this is processing for making the energization phase switching timing appropriate in the next step 122. .

  In the next step 122, the controller 18 controls each transistor so as to switch the energized phase. Then, the process returns to step 100 above.

  On the other hand, if a negative determination is made in step 106 (when it is determined that the relative position of the rotor with respect to the stator is not within the range of 0 ° to 30 °, 150 ° to 210 °, and 330 ° to 360 °) ) Go to the next step 126.

  In the next step 126, it is determined whether or not the relative position of the rotor with respect to the stator is within a range of 30 degrees or more and less than 90 degrees, or 210 degrees or more and less than 270 degrees.

  If it is determined in step 126 that the relative position of the rotor with respect to the stator is within the range of 30 degrees or more and less than 90 degrees, or 210 degrees or more and less than 270 degrees, the process proceeds to the next step 128.

  In step 128, the V-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the W-phase armature winding (terminal C), and the U-phase armature winding is set. Connect the negative terminal to the line (terminal A). The positive voltage application time is a value obtained in advance by experiments every 30 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor.

  In the next step 130, the V-phase voltage is detected.

  In step 132, the V-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the U-phase armature winding (terminal A), and the W-phase armature winding is set. Connect the negative terminal to the line (terminal C). The positive voltage application time is a value obtained in advance by experiments every 30 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor.

  In the next step 134, the V-phase voltage is detected, and the process proceeds to step 136.

  In the first step 136, the magnitude relationship is determined by comparing the V-phase voltage detected in step 130 with the V-phase voltage detected in step 134.

  In step 136 after the second time, first, the magnitude relationship is determined by comparing the V-phase voltage detected in step 130 with the V-phase voltage detected in step 134. Then, the magnitude relation determined in the previous step 136 is compared with the magnitude relation determined this time to determine whether the magnitude relation has changed. For example, in the previous magnitude relationship, the V-phase voltage detected in step 130 was greater than the V-phase voltage detected in step 134, whereas in the current magnitude relationship, the V-phase voltage was detected in step 134. If the V-phase voltage is greater than the V-phase voltage detected in step 130, it is determined that the magnitude relationship has changed.

  If it is determined in step 136 that the magnitude relationship has not changed, the process proceeds to step 128. On the other hand, if it is determined in step 136 that the magnitude relationship has changed, the process proceeds to the next step 118.

  On the other hand, when a negative determination is made at step 126 (when it is determined that the relative position of the rotor with respect to the stator is not within any range of 30 degrees to less than 90 degrees and 210 degrees to less than 270 degrees), the next step Go to 138.

  In the next step 138, it is determined whether or not the relative position of the rotor with respect to the stator is within a range of 90 degrees to less than 150 degrees and 270 degrees to less than 330 degrees.

  If it is determined in step 138 that the relative position of the rotor with respect to the stator is within any range of 90 degrees to less than 150 degrees and 270 degrees to less than 330 degrees, the process proceeds to the next step 140.

  In step 140, the W-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the V-phase armature winding (terminal B), and the U-phase armature winding is set. Connect the negative terminal to the line (terminal A). The positive voltage application time is a value obtained in advance by experiments every 30 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor.

  In the next step 142, the W-phase voltage is detected.

  In step 144, the W-phase armature winding is opened (not connected), the positive voltage of the DC power supply 16 is applied to the U-phase armature winding (terminal A), and the V-phase armature winding is set. Connect the negative terminal to the line (terminal B). The positive voltage application time is a value obtained in advance by experiments every 30 degrees so that the rotor rotates appropriately, and is determined according to the relative position of the rotor.

  In the next step 146, the W-phase voltage is detected, and the process proceeds to step 148.

  In the first step 148, the magnitude relationship is determined by comparing the W-phase voltage detected in step 142 with the W-phase voltage detected in step 146.

  In the second and subsequent steps 148, first, the magnitude relationship is determined by comparing the W-phase voltage detected in step 142 and the W-phase voltage detected in step 146. Then, the magnitude relationship determined in the previous step 148 is compared with the magnitude relationship determined this time to determine whether the size relationship has changed. For example, in the previous magnitude relationship, the W-phase voltage detected in step 142 is greater than the W-phase voltage detected in step 146, whereas in the current magnitude relationship, the W-phase voltage is detected in step 146. If the W-phase voltage is greater than the W-phase voltage detected in step 142, it is determined that the magnitude relationship has changed.

  If it is determined in step 148 that the magnitude relationship has not changed, the process proceeds to step 140 described above. On the other hand, if it is determined in step 148 that the magnitude relationship has changed, the process proceeds to the next step 118.

  On the other hand, when a negative determination is made at step 138 (when it is determined that the relative position of the rotor with respect to the stator is not within any range of 90 degrees to less than 150 degrees and 270 degrees to less than 330 degrees), the process proceeds to step 106. Return.

  As described above, the brushless motor driving apparatus 10 according to the present embodiment includes a stator having a plurality of motor windings each generating a magnetic field and a rotor that is rotationally driven by a magnetic field generated by each of the plurality of motor windings. The first direction and the first direction are a pair of energized layer motor windings to which driving power is supplied among the motor windings of a plurality of phases based on the relative position of the rotor of the brushless motor 12 provided to the stator. In the second direction, which is the opposite direction, the driving power from the DC power source 16 as the driving power supply means for supplying the driving power to each motor winding is alternately supplied so that the rotor is relative to the stator. The DC power supply 16 is controlled so as to be rotated in a predetermined direction.

  The first voltage, which is the phase voltage of the motor winding of the non-conduction phase when drive power is supplied to the motor winding of the pair of energization phases in the first direction, and the pair of energizations in the second direction Detecting a second voltage, which is a phase voltage of the non-energized motor winding when drive power is supplied to the phase motor winding, and based on a change in the magnitude relationship between the first voltage and the second voltage Thus, the relative position of the rotor with respect to the stator is determined. Therefore, according to the brushless motor driving apparatus 10 of the present embodiment, the relative position of the rotor with respect to the stator can be determined without using an expensive current sensor. That is, the relative position of the rotor with respect to the stator can be determined without cost as compared with the prior art.

  It should be noted that the present invention is not limited to such embodiments, and it will be apparent to those skilled in the art that other various embodiments are possible within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Brushless motor drive device, 12 ... Brushless motor, 14 ... Switching element group, 16 ... DC power supply, 18 ... Controller, 20 ... Observer

Claims (5)

Based on the relative position of the rotor with respect to the stator of a motor comprising a stator having a plurality of phase motor windings each generating a magnetic field and a rotor driven to rotate by the magnetic field generated by each of the plurality of phase motor windings. In the motor windings of the pair of energization layers to which driving power is supplied among the motor windings of the plurality of phases, the first direction and the second direction opposite to the first direction, The drive power supply means is arranged such that drive power from drive power supply means for supplying drive power to the motor windings is alternately supplied so that the rotor is rotationally driven in a predetermined direction relative to the stator. Control means for controlling;
A first voltage that is a phase voltage of a motor winding in a non-conduction phase when drive power is supplied to the pair of energization phase motor windings in the first direction, and the pair in the second direction. Detecting means for detecting a second voltage that is a phase voltage of the non-energized phase motor winding when drive power is supplied to the energized phase motor winding;
Discrimination means for discriminating a relative position of the rotor with respect to the stator based on a change in a magnitude relationship between the first voltage and the second voltage;
A motor driving device.   The control means is configured such that the driving power from the driving power supply means is alternately determined in advance in the first direction and the second direction on the motor windings of the pair of energization layers. 2. The motor drive device according to claim 1, wherein the drive power supply means is controlled so that the rotor is rotationally driven in a predetermined direction relative to the stator.   When the rotation of the rotor is stopped, the control means has the same driving power time in the first direction and the second direction supplied alternately to the motor windings of the pair of energized phases. The motor driving device according to claim 2.   The detecting means detects the first voltage after a lapse of a predetermined period from the start of supply of driving power in the first direction to the pair of energized phase motor windings, and detects the pair of energized phases. 4. The motor driving device according to claim 1, wherein the second voltage is detected after a predetermined period has elapsed since the supply of driving power in the second direction to the motor winding is started. Based on the relative position of the rotor with respect to the stator of a motor comprising a stator having a plurality of phase motor windings each generating a magnetic field and a rotor driven to rotate by the magnetic field generated by each of the plurality of phase motor windings. In the motor windings of the pair of energization layers to which driving power is supplied among the motor windings of the plurality of phases, the first direction and the second direction opposite to the first direction, The drive power supply means is arranged such that drive power from drive power supply means for supplying drive power to the motor windings is alternately supplied so that the rotor is rotationally driven in a predetermined direction relative to the stator. Control
A first voltage that is a phase voltage of a motor winding in a non-conduction phase when drive power is supplied to the pair of energization phase motor windings in the first direction, and the pair in the second direction. A second voltage that is a phase voltage of the non-energized phase motor winding when driving power is supplied to the energized phase motor winding;
Determining a relative position of the rotor with respect to the stator based on a change in a magnitude relationship between the first voltage and the second voltage;
A method for determining a relative position of a rotor provided in a motor.

Images