JP5206619B2 - Drive method and drive control apparatus for brushless three-phase DC motor - Google Patents

Description

  The present invention relates to a method for driving a brushless three-phase DC motor and a drive control device for a brushless three-phase DC motor that controls the driving of the motor.

  Conventionally, in brushless three-phase DC motors, the inverter circuit determines the commutation timing and performs synchronous operation to control the energization phase to the armature, and the rotor position is detected when the number of rotations that can detect the rotor position is reached. Then, motor drive control for controlling the energization phase is performed. And in the said motor drive control, the positioning process of the rotor in motor stop states, such as before synchronous operation, is an important control process. Conventional brushless three-phase DC motors are known that employ a sensorless system that does not include a Hall element in order to detect the magnetic pole position of the rotor (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, in a sensorless brushless three-phase DC motor, a fixed phase as a first positioning is energized at start-up to rotate the rotor to a certain position and then energize the remaining phases as a second positioning. And the technique which fixes a rotor to the position different from the stop position determined by 1st positioning and starts a driving | operation is disclosed.

  Next, in Patent Document 2, based on an induced voltage generated by applying a startup current according to a startup pattern selected for the armature in a stopped state of the rotor and moving the rotor in response to the startup current. A forward / reverse determination of the rotation direction of the rotor is performed. Then, when it is determined that the rotation direction of the rotor is normal rotation, the position of the rotor is detected based on the induced voltage, and the armature is applied to the rotor according to the detected position. Closed loop drive with a duty of 100% is performed to drive the rotor while determining the currents to flow in the U phase, V phase and W phase. Then, after the rotor reaches a predetermined rotational speed by closed-loop driving with a duty of 100%, the rotational speed of the rotor is controlled by controlling the duty to complete the start-up control.

  On the other hand, when it is determined that the rotor is reverse, the rotation of the rotor is stopped. Next, a startup current is applied to the armature according to the startup pattern selected again, and the forward / reverse determination of the rotational direction of the rotor is performed again based on the induced voltage as described above.

JP-A-4-31390 JP 2002-78376 A

  In the technique of the above-mentioned patent document 1, since the rotor positioning process is performed substantially twice, there is a problem that it takes time until the rotor positioning is completed before starting the motor. Moreover, the positioning process described in Patent Document 1 may increase the rotational movement range of the rotor depending on the initial position of the rotor.

  Further, in the technique of Patent Document 2, when it is determined that the rotation is reverse in the above-described forward / reverse rotation determination of the rotor, the energization is performed according to the re-selected activation pattern. There is a problem that it takes time to complete the start-up of the motor due to the repetition.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a brushless three-phase DC motor drive method and a brushless three-phase DC motor drive control device that can shorten the time required to start the motor. There is to do.

The invention according to claim 1 is an invention relating to a driving method of a brushless three-phase DC motor including an armature having a three-phase winding and a rotor having a permanent magnet,
Prior to starting the brushless three-phase DC motor from the stopped state, the rotor magnetic poles are based on the result of comparing the reference voltage with the induced voltage generated in the non-energized phase winding when the three-phase winding is energized in two phases. A position detecting step for detecting a position;
A position determining step for determining a positioning angle of the rotor based on the magnetic pole position of the rotor detected in the position detecting step;
A positioning process step for energizing the phase winding to be energized in order to position the rotor at the positioning angle determined in the position determining step,
In the position detection step, according to the comparison result between the induced voltage and the reference voltage, when the comparison result has a negative induced voltage polarity , the electrical angle is π / 2 radians in the rotation direction from the reference position where the non-energized phase winding is located. This is the range up to the position where the angular displacement occurs , and in the comparison result where the induced voltage polarity is positive, from the reference position where the non-energized phase winding is located to the position where the electrical angle is displaced by π / 2 radians in the reverse rotation direction detecting a first angular range in the range, the estimation range consisting of a second angular range in a relationship of the first angle range and the point symmetry about the center of rotation as the magnetic pole position of the rotor,
In the position determination step, the positioning angle of the rotor is determined within an angle range that is not included in the estimation range detected in the position detection step and is an angle of electrical angle within π / 2 radians. Features.

  According to the present invention, in the position detecting step, the estimated range including the predetermined angle range defined with reference to the position corresponding to the non-energized phase winding is detected as the magnetic pole position of the rotor, and the position determining step In order to determine the positioning angle of the rotor within an angle range that is not included in the estimation range and is within π / 2 radians, stop the positioning angle for positioning the rotor before starting. The rotation angle can be determined to be less than a half rotation with respect to the magnetic pole position of the rotor in the state. As a result, the angular displacement amount of the rotor from the initial position in the stopped state to the positioning position before startup can be suppressed, and the angular displacement amount can be small, so that the positioning operation of the rotor is easy to converge. . Therefore, it is possible to provide a method for driving a brushless three-phase DC motor that can shorten the time required to start the motor.

According to the second aspect of the present invention, in the position determination step, the positioning angle is changed from the position corresponding to the magnetic pole formed in the armature when the two-phase energization is performed to the electrical angle in either the rotational direction or the reverse rotational direction. The position is determined to be displaced by π / 6 radians.

  According to this invention, the positioning angle of the rotor in the position determination step is displaced by π / 6 radians from the position corresponding to the magnetic pole of the armature when the two-phase energization is performed in either the rotational direction or the reverse rotational direction. Determine the position. As a result, the magnetic poles of the rotor are positioned at the magnetic pole positions that are easily formed by energizing the three-phase windings, so that the convergence of the rotating operation is improved and the time until convergence to the positioning positions is increased. Further, it can be shortened. Therefore, it is possible to further shorten the time required for starting the motor.

  According to the third aspect of the invention, prior to the two-phase energization performed before the position detection step, the energization performed in the positioning processing step is the pre-energization for flowing current in a predetermined direction to the three-phase winding. It has a preliminary energization step that is performed in a shorter time than the time.

  According to the present invention, preliminary energization is performed before the two-phase energization and the rotor is rotated from the stopped state even a little, so that the rotor rotates with a large rotational load at the start of the two-phase energization. Even in a difficult case, the rotor starts to rotate by pre-energization and the rotational load is reduced, so that the induced voltage of the non-energized phase can be reliably detected during two-phase energization. Therefore, the detection accuracy of the magnetic pole position of the rotor is improved, which can contribute to shortening the time until the motor is started.

  According to the fourth aspect of the present invention, the preliminary energization in which current is supplied to the three-phase winding in a predetermined direction before the positioning process step is performed in a shorter time than the energization time performed in the positioning process step. It has an energization step.

  According to the present invention, preliminary energization is performed before the positioning process, and the rotor is rotated as little as possible from the stopped state, so that the rotor load is large at the start of the two-phase energization and the rotor is difficult to rotate. Even in this case, the rotor starts to rotate due to the preliminary energization and the rotational load is reduced. Therefore, the rotor can be rotated reliably and smoothly during the positioning process. Therefore, the speed of the rotor positioning process and the positioning accuracy are improved, which can contribute to shortening the time until the motor is started.

  According to the invention described in claim 5, in the position detection step, when the two-phase energization is performed by the pulse width modulation control, the induced voltage is detected after a predetermined time has elapsed since the pulse width modulation control was turned on. It is characterized by that. According to the present invention, since the induced voltage can be detected while avoiding the vibration waveform that is likely to occur immediately after the PWM control is turned on, the rotor position can be detected smoothly and quickly.

  According to the invention described in claim 6, in the position detection step, when the two-phase energization is performed by the pulse width modulation control, the induced voltage is applied immediately after the gate signal based on the pulse width modulation control is turned off. It is characterized by detecting. According to the present invention, since the induced voltage can be detected while avoiding the response delay of the actual terminal voltage waveform with respect to the gate signal, the rotor position can be detected smoothly and quickly.

  According to the invention described in claim 7, the reference voltage is a virtual neutral point voltage or a voltage corresponding to half of the power supply voltage.

The invention according to claim 9 is an invention relating to a drive control device for a brushless three-phase DC motor that controls the driving of a brushless three-phase DC motor including an armature having a three-phase winding and a rotor having a permanent magnet. There,
Prior to starting the brushless three-phase DC motor from the stopped state, the rotor magnetic poles are based on the result of comparing the reference voltage with the induced voltage generated in the non-energized phase winding when the three-phase winding is energized in two phases. Position detecting means for detecting the position; position determining means for determining the rotor positioning angle based on the magnetic pole position of the rotor detected by the position detecting means; and the rotor at the positioning angle determined by the position determining means. Positioning processing means for energizing the phase winding to be energized for positioning, and
In accordance with the comparison result between the induced voltage and the reference voltage, the position detection means is π / 2 radians in electrical rotation direction from the reference position where the non-energized phase winding is positioned when the comparison result has a negative induced voltage polarity. This is the range up to the position where the angular displacement occurs , and in the comparison result where the induced voltage polarity is positive, from the reference position where the non-energized phase winding is located to the position where the electrical angle is displaced by π / 2 radians in the reverse rotation direction An estimated range consisting of a first angle range that is a range and a second angle range that is point-symmetric with the first angle range with respect to the rotation center, is detected as the magnetic pole position of the rotor;
The position determining means determines the positioning angle of the rotor within an angular range that is not included in the detected estimated range and is an electrical angle within a range of π / 2 radians.

  According to this invention, the position detecting means detects the estimated range including the predetermined angle range defined with reference to the position corresponding to the non-energized phase winding as the magnetic pole position of the rotor, and the position determining means The positioning angle of the rotor is determined within an angle range that is not included in the estimation range and is an angle range within π / 2 radians. For this reason, the positioning angle for positioning the rotor before activation can be determined to be a rotation angle that is less than half a rotation with respect to the magnetic pole position of the rotor in the stopped state. As a result, the angular displacement amount of the rotor from the initial position in the stopped state to the positioning position before startup can be suppressed, and the angular displacement amount can be small, so that the positioning operation of the rotor is easy to converge. . Therefore, it is possible to provide a drive control device for a brushless three-phase DC motor that can shorten the time required to start the motor.

According to the tenth aspect of the present invention, the position determining means sets the positioning angle from the position corresponding to the magnetic pole formed in the armature when the two-phase energization is performed to the electrical angle in either the rotational direction or the reverse rotational direction. The position is determined to be displaced by π / 6 radians.

  According to this invention, the positioning angle of the rotor by the position determining means is displaced by π / 6 radians in either the rotational direction or the reverse rotational direction from the position corresponding to the magnetic pole of the armature when the two-phase energization is performed. Determined to position. As a result, the magnetic poles of the rotor are positioned at the magnetic pole positions that are easily formed by energizing the three-phase windings, so that the convergence of the rotating operation is improved and the time until convergence to the positioning positions is increased. Further, it can be shortened. Therefore, it is possible to further shorten the time required for starting the motor.

  According to invention of Claim 8 or Claim 11, a brushless three-phase DC motor is an actuator of a fuel pump, It is characterized by the above-mentioned.

It is a circuit diagram which shows schematic structure of the drive control apparatus of the brushless three-phase DC motor in 1st Embodiment of this invention. It is a circuit diagram which shows the other example of the drive control apparatus of the brushless three-phase DC motor shown in FIG. It is a flowchart explaining the starting control process of the brushless three-phase DC motor in 1st Embodiment. It is a figure explaining an example of rotor magnetic pole position detection (when the estimated range is 60 degrees to 150 degrees) and positioning processing (when the positioning angle ranges are 330 degrees to 360 degrees and 0 degrees to 60 degrees), (A) is explanatory drawing which shows the estimation range and positioning angle of the rotor position in this case, (b) is explanatory drawing which shows the relationship between the induced voltage of an open phase, and a reference voltage, (c) is positioning processing It is explanatory drawing which shows the behavior of the rotor in. It is a figure explaining an example of rotor magnetic pole position detection (when the estimation range is 240 degrees to 330 degrees) and positioning processing (when the positioning angle ranges are 330 degrees to 360 degrees and 0 degrees to 60 degrees), (A) is explanatory drawing which shows the estimation range and positioning angle of the rotor position in this case, (b) is explanatory drawing which shows the relationship between the induced voltage of an open phase, and a reference voltage, (c) is positioning processing It is explanatory drawing which shows the behavior of the rotor in. It is a figure explaining an example of rotor magnetic pole position detection (when the estimated range is 330 degrees to 360 degrees and 0 degrees to 60 degrees) and positioning processing (when the positioning angle range is 240 degrees to 330 degrees), (A) is explanatory drawing which shows the estimation range and positioning angle of the rotor position in this case, (b) is explanatory drawing which shows the relationship between the induced voltage of an open phase, and a reference voltage, (c) is positioning processing It is explanatory drawing which shows the behavior of the rotor in. It is a figure explaining an example of a rotor magnetic pole position detection (when the estimation range is 150 degrees to 240 degrees) and positioning processing (when the positioning angle range is 240 degrees to 330 degrees), (a) in this case (B) is an explanatory view showing the relationship between the induced voltage of the open phase and the reference voltage, and (c) shows the behavior of the rotor in the positioning process. It is explanatory drawing shown. It is a table | surface explaining the corresponding | compatible relationship between various two-phase electricity supply, the estimation range of a rotor, and the range of a positioning process. It is a voltage waveform which shows the relationship of 1/2 voltage of the terminal voltage VW of the open phase when not implementing PWM control, the virtual neutral point voltage VN, and DC voltage VDC. (A) is a figure which shows the terminal voltage waveform of the open phase in the case of implementing PWM control, (b) is a figure which expanded a part of (a). It is a flowchart explaining the starting process of the brushless three-phase DC motor in 2nd Embodiment. It is a flowchart explaining the starting process of the brushless three-phase DC motor in 3rd Embodiment.

  A plurality of modes for carrying out the present invention will be described below with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also a combination of the embodiments even if they are not clearly shown unless there is a problem with the combination. It is also possible.

(First embodiment)
FIG. 1 is a circuit diagram showing a schematic configuration of a drive control device for a brushless three-phase DC motor in the first embodiment. The drive control device for the brushless three-phase DC motor of this embodiment can be used for various actuators, but here it is used for the actuator of an in-vehicle fuel pump.

  As shown in FIG. 1, a brushless three-phase DC motor drive control device 1 (hereinafter also simply referred to as “brushless motor drive control device 1”) includes a voltage application unit 20 that applies a voltage to a motor 10, and an inverter circuit 70. A drive circuit 30 for driving the switching element, a control circuit 50 for controlling the inverter circuit 70 via the drive circuit 30, and a position detection means 40 for detecting the magnetic pole position of the rotor 15.

  The voltage application unit 20 includes a power source 60 and an inverter circuit 70. The voltage application unit 20 applies a voltage to the motor 10, and, for example, energizes a phase winding to be energized before the motor 10 is started, thereby rotating the rotor. It is also a positioning processing means for positioning 15. The power source 60 is a vehicle-mounted battery.

  The motor 10 is a three-phase brushless DC motor, which includes an armature 14 and a rotor 15 that rotates with respect to the armature 14, and a sensorless system that does not include a hall element or the like for detecting the position of the rotor 15. Motor. The rotor 15 is a disk-shaped member having a magnetic pole, and a permanent magnet is stuck on the surface, for example. An inverter circuit 70 is connected to the three phases (the U-phase winding 11, the V-phase winding 12, and the W-phase winding 13) of the brushless DC motor formed on the armature 14.

  The inverter circuit 70 is a three-phase inverter circuit, and switches application of the voltage on the power supply 60 side to each of the three phases of the motor 10. The inverter circuit 70 includes six MOSFETs (metal-oxide-semiconductor field-effect transistors) 71, 72, 73, 74, 75, 76 (hereinafter simply referred to as “FETs 71, 72, 73, 74”). , 75, 76 "). These FETs 71 to 76 function as switching elements, and are turned on or off between the drain and the source depending on the potential of the gate to be conducted or cut off. Hereinafter, the FETs 71, 72, 73, 74, 75, and 76 may be expressed as SU +, SV +, SW +, SU−, SV−, and SW−, respectively. Each gate of the FETs 71 to 76 is connected to the output terminal of the drive circuit 30. With these configurations, the control circuit 50 can switch ON / OFF of the FETs 71 to 76 via the drive circuit 30.

  The position detection means 40 includes three comparators 41, 42, 43 and resistors 44, 45, 46, 47, 48, 49, and outputs a signal for detecting the magnetic pole position of the rotor 15 to the control circuit 50. To do. One end of each phase winding 11, 12, 13 of the motor 10 is connected to resistors 44, 45, 46. The resistor 44 is connected to the input terminal (+ side terminal) of the comparator 41, and the resistor 45 is connected to the comparator 42. A resistor 46 is connected to the input terminal (+ side terminal) of the comparator 43 and the input terminal (+ side terminal). Further, one end of each phase winding 11, 12, 13 of the motor 10 is connected to one common point via resistors 47, 48, 49, and this common connection point becomes a virtual neutral point. Yes. The inverting input terminals of the comparators 41, 42, and 43 are connected to this virtual neutral point. Each of the comparators 41, 42, and 43 compares the induced voltage of each phase input to the input terminal with the voltage of the virtual neutral point used as the reference voltage, and compares the comparison result (induced voltage and reference voltage). Is output as a position detection signal of the rotor 15. With this configuration, when so-called two-phase energization is performed, the comparator corresponding to the open phase that is not energized is either positive or negative obtained as a result of subtracting the reference voltage from the induced voltage generated in the open phase. The polarity (induced voltage polarity) is output to the control circuit 50 as a position detection signal.

  The control circuit 50 controls the output of the motor 10 by controlling the switching of the FETs 71 to 76 of the inverter circuit 70 via the drive circuit 30. The control circuit 50 estimates the magnetic pole position of the rotor 15 based on the position detection signal of the rotor 15 input from the comparators 41, 42, and 43 of the position detection means 40 before starting the motor 10 from the stopped state. Is detected. Further, the control circuit 50 determines the position of the rotor 15 before starting the motor at a positioning angle associated in advance according to the estimated range. As described above, the control circuit 50 functions as a position detection unit that detects the estimation range of the magnetic pole position of the rotor 15 and also functions as a position determination unit that determines the positioning angle of the rotor 15 before starting the motor. Further, a detection signal indicating a current flowing through the inverter circuit 70 (that is, the motor 10) is input to the control circuit 50.

  Further, in the above configuration, when the rotor 15 is stopped, no induced voltage is generated from the windings 11 to 13 of the armature 14, so that the position of the rotor 15 cannot be detected. For this reason, the control circuit 50 performs forced commutation at a certain fixed period. When the rotor 15 starts to rotate, position detection signals are output from the comparators 41 to 43 based on the induced voltages generated from the phase windings 11 to 13 of the armature 14, and the control circuit 50 The next commutation timing, that is, the switching timing of the energized phase, is determined based on this position detection signal, and commutation is executed at this timing, so-called sensorless drive control is performed. Further, the control circuit 50 increases the rotational speed of the motor 10 by increasing the duty of PWM control (pulse width modulation control). The control circuit 50 can control the rotation speed by controlling the duty of the PWM control. The control circuit 50 detects the rotational speed based on the position detection signal, and feedback-controls the duty of the PWM control so that the motor 10 becomes the set rotational speed.

  As another example of the drive control device 1 for the brushless motor described above, a drive control device 1A for a brushless three-phase DC motor as shown in FIG. 2 (hereinafter, also simply referred to as “brushless motor drive control device 1A”). It may be adopted. In this case, unlike the brushless motor drive control device 1, the brushless motor drive control device 1A employs ½ VDC, which is half the power supply voltage VDC, as the reference voltage, and as shown in FIG. The position detection unit 40A is provided.

  The position detection means 40A includes three comparators 41, 42, and 43, resistors 44, 45, and 46, and a voltage dividing circuit including two resistors 81 and 82 having the same resistance value. The resistor 81 is connected to the positive DC power supply bus, the resistor 82 is connected to the negative DC power supply bus, and the voltage dividing point between the resistors is connected to a common point (common connection point). . This common connection point is connected to each inverting input terminal of the comparators 41, 42, and 43, and a voltage value (1 / 2VDC) that is half the DC voltage VDC applied by the power supply 60 is used as the reference voltage. Is output to the inverting input terminal. Each comparator 41, 42, 43 compares the induced voltage of each phase input to the input terminal with the above-mentioned 1/2 VDC adopted as the reference voltage, and compares the comparison result (the induced voltage and the reference voltage (Difference) is output as a position detection signal of the rotor 15. The brushless motor drive control device 1 </ b> A is the same as the brushless motor drive control device 1 with respect to other components, their operations, and activation processing described later.

  Next, start control performed prior to the start of the motor 10 in the brushless motor drive control devices 1 and 1A of the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart for explaining start-up control processing of the brushless three-phase DC motor. The start-up control executed mainly by the control circuit 50 starts when the ignition switch is turned on, and first, two-phase energization is executed for a predetermined two-phase winding (step 10). The two-phase energization executed in step 10 energizes a predetermined phase winding stored in the control circuit 50 or the like. The two-phase energization described below is an example of two-phase energization (hereinafter also referred to as “U → V two-phase energization”) in which a current flows from the U-phase winding 11 to the V-phase winding 12. In the two-phase energization process of U → V, the control circuit 50 performs switching control via the drive circuit 30 so that the FET 71 (SU +) is turned on and the FET 75 (SV−) is turned on. Thus, for example, as shown in FIG. 4A, the armature 14 has an angle of 330 degrees (11π / 6 radians) in the rotation direction X in which the U phase, the V phase, and the W phase are angularly displaced in order from the U phase. An S pole is formed at the displaced position. Due to the magnetic field generated by this energization, the rotor 15 rotates and an induced voltage is generated in the W phase, which is a non-energized open phase.

  Next, at step 20, the control circuit 50 acquires the induced voltage polarity obtained by the difference between the induced voltage generated in the open phase and the reference voltage (virtual neutral point voltage or 1/2 VDC) as a position detection signal. Specifically, the comparator 43 outputs the induced voltage polarity resulting from the difference between the induced voltage generated in the W phase and the reference voltage to the control circuit 50 as a position detection signal.

  The control circuit 50 detects the magnetic pole position of the rotor 15 (step 25). The detection of the magnetic pole position is obtained on the assumption that the magnetic pole position is in an estimated range determined in advance according to the induced voltage polarity. For example, when the induced voltage polarity is negative, the magnetic pole position is the first from the reference position where the open phase (W phase) is located to the position where the angular displacement is 90 degrees (π / 2 radians) in the rotation direction X. 5 (a hatched portion in FIG. 5A, that is, a range of θ between 240 degrees and 330 degrees) and a second angle range (point of symmetry with respect to the rotation center) that is point-symmetric with the first angle range. (A) is detected as being present in an estimated range consisting of the shaded portion, that is, θ is in the range of 60 degrees to 150 degrees. In addition, when the induced voltage polarity is positive, the magnetic pole position is from the reference position where the open phase (W phase) is located to the position where it is angularly displaced 90 degrees (π / 2 radians) in the reverse rotation direction Y. A first angle range (the hatched portion in FIG. 7A, that is, a range where θ is 150 degrees to 240 degrees) and a second angle range (point-symmetrical to the first angle range with respect to the rotation center) In FIG. 6A, it is detected as existing in the hatched portion, that is, in an estimation range consisting of θ in the range of 0 to 60 degrees and 330 to 360 degrees.

  Next, at step 30, determination of the magnetic pole position range of the rotor 15 (positive / negative determination of induced voltage polarity) and a positioning angle corresponding to the determination are determined. Next, the control circuit 50 executes a positioning process for energizing the phase winding to be energized in order to position the rotor 15 at the determined positioning angle (steps 40 and 50 corresponding to the positioning process steps). ).

  If it is determined in step 30 that the induced voltage polarity is negative, the control circuit 50 controls switching of the FETs 71 to 76 via the drive circuit 30 to control the energization state of each phase winding, thereby causing the The south pole is formed at an arbitrary angle included in the positioning angle in the range of 360 degrees and in the range of 0 to 60 degrees. This positioning angle is an angle range that is not included in the estimated range that is obtained when the induced voltage polarity is negative, and is set to a range that includes an angle within 90 degrees (π / 2 radians). As an example of the energization process that satisfies the determined positioning angle, the control circuit 50 energizes the current so that the current flows from the U-phase winding 11 to the V-phase winding 12 and the W-phase winding 13 in Step 40 (hereinafter, “ From the viewpoint of early convergence of the magnetic pole position of the rotor 15, it is preferable to form the S pole at 0 degree (position corresponding to the U-phase winding 11). . In the energization process of U → V, W, the control circuit 50 performs switching control to turn on the FET 71 (SU +), the FET 75 (SV−), and the FET 76 (SW−) via the drive circuit 30.

  On the other hand, if it is determined in step 30 that the induced voltage polarity is positive, the control circuit 50 controls the switching of the FETs 71 to 76 via the drive circuit 30 to control the energization state of each phase winding, thereby 240. The south pole is formed at an arbitrary angle included in the positioning angle in the range of degrees to 330 degrees. This positioning angle is an angle range that is not included in the estimated range that is obtained when the induced voltage polarity is positive, and is set to a range that includes an angle within 90 degrees (π / 2 radians). As an example of energization processing that satisfies the determined positioning angle, the control circuit 50 energizes the current so that current flows from the U-phase winding 11 and the W-phase winding 13 to the V-phase winding 12 in Step 50 (hereinafter, “ The magnetic pole position of the rotor 15 is that the S pole is formed at a position displaced by 300 degrees (5π / 3 radians) in the rotation direction X from the position of the U phase. This is preferable from the viewpoint of early convergence. In the energization process of U, W → V, the control circuit 50 performs switching control so that the FET 71 (SU +), the FET 73 (SW +), and the FET 75 (SV−) are turned on via the drive circuit 30.

  Each processing of Step 40 and Step 50 is performed for a predetermined time in consideration of the time until the rotor 15 which continues to rotate due to inertia is locked at the determined positioning angle. Note that the estimated range and the positioning angle obtained when the U → V two-phase energization process is executed as in the control process of FIG. 3 are as described in the upper part of the chart shown in FIG. In the start control, by determining the estimation range and the positioning angle, the useless behavior of the rotor 15 is suppressed and the time until the start of the motor 10 is shortened.

  After performing the positioning process of the rotor 15 as in step 40 or 50, in step 60, the inverter circuit 70 determines the commutation timing and starts the synchronous operation for controlling the energization phase to the armature 14. When the number of rotations at which the position of the rotor 15 can be detected is reached, the position of the rotor 15 is detected (step 70) and the energization phase is controlled. After the rotational speed of the rotor 15 reaches a predetermined value, the rotational speed control is executed by duty control to start sensorless drive control (step 80), and the start control of the motor 10 is finished.

  Next, the behavior of the rotor 15 during the magnetic pole position detection and positioning process of the rotor 15 will be described with reference to FIGS. The simulation conditions shown in FIGS. 4B, 5B, 6B, and 7B are as follows: the power supply voltage is 12 V, the energization time is 5 msec, and the reference voltage is 1/2 voltage of the DC voltage VDC. It is what.

  4A and 4C show the case where the induced voltage polarity is negative when U → V two-phase energization is performed, and the estimated range is 60 degrees to 150 degrees (π / 3 to 5π / 6). 5A and 5C show the behavior of the rotor 15 in the case of radians), and FIGS. 5A and 5C show the case where the induced voltage polarity is negative and the estimated range is 240 degrees to 330 degrees (4π / 3 to 11π / 6). The behavior of the rotor 15 at radians) is shown. Further, during the two-phase energization of U → V, as shown in FIGS. 4A and 5A, the armature 14 positioned outside the rotor 15 has an N pole of 150 degrees and an S pole of 330 degrees. Formed. Then, by the two-phase energization of U → V, the N pole of the rotor 15 in FIG. 4A rotates from the position included in 60 degrees to 150 degrees away from the W phase in the reverse rotation direction Y, and FIG. As shown in FIGS. 4B and 5B, the N pole of the rotor 15 in FIG. 4A rotates away from the W phase in the rotation direction X from a position included in 240 to 330 degrees. A negative induced voltage polarity in which the reference voltage is larger than the induced voltage of the open phase (W phase) is detected.

  Next, since the positioning angle of the rotor 15 is determined in the range of 0 to 60 degrees and 330 to 360 degrees, the S pole of the armature 14 is formed at this positioning angle, so that FIG. The rotor 15 continues to rotate in the reverse rotation direction Y, and the rotor 15 in FIG. 5C continues to rotate in the rotation direction X. In particular, in FIGS. 4 (c) and 5 (c), U → V and W are energized to set the positioning angle to the 0 degree position, so the rotor 15 in FIG. 4 (c) is reversed during the positioning process. The rotor 15 in FIG. 5C rotates by the broken arrow in the rotation direction Y during the positioning process. Therefore, the magnetic pole (N pole) of the rotor 15 indicated by the black circle is positioned by a rotational movement of 150 degrees at the maximum in the case of FIG. 4A, and 120 degrees at the maximum in the case of FIG. Positioning is performed by rotational movement.

  Next, in the case where U → V two-phase energization is performed, FIGS. 6A and 6C are when the induced voltage polarity is positive, and the estimated ranges are 330 degrees to 360 degrees and 0 degrees to 60 degrees. FIG. 7A and FIG. 7C show the behavior of the rotor 15 when the induced voltage is positive (11π / 6 to 2π radians and 0 to π / 3 radians). The behavior of the rotor 15 when the estimated range is 150 degrees to 240 degrees (5π / 6 to 4π / 3 radians) is shown. Further, during U → V two-phase energization, as shown in FIGS. 6A and 7A, the armature 14 positioned outside the rotor 15 has an N pole of 150 degrees and an S pole of 330 degrees. Formed. Then, due to the two-phase energization of U → V, the N pole of the rotor 15 in FIG. 6A rotates from the position in the estimated range so as to approach the W phase in the reverse rotation direction Y, and in FIG. The N pole of the rotor 15 rotates from the position in the estimated range so as to approach the W phase in the rotation direction X, and the reference voltage is set to the open phase (W as shown in FIGS. 6B and 7B). A positive induced voltage polarity smaller than the induced voltage of the phase is detected.

  Next, since the positioning angle of the rotor 15 is determined in the range of 240 degrees to 330 degrees, the S pole of the armature 14 is formed at this positioning angle, so that the rotor 15 in FIG. Rotating in the reverse rotation direction Y, the rotor 15 in FIG. 7C continues to rotate in the rotation direction X. In particular, in FIGS. 6 (c) and 7 (c), U, W → V are energized and the positioning angle is set to a position of 300 degrees. Therefore, the rotor 15 in FIG. 6 (c) is reversed during the positioning process. The rotor 15 in FIG. 7C is rotated and moved by the broken arrow in the rotational direction X during the positioning process. Therefore, the magnetic poles (N poles) of the rotor 15 indicated by black circles are positioned by a rotational movement of 120 degrees at the maximum in the case of FIG. 6A, and 150 degrees at the maximum in the case of FIG. Positioning is performed by rotational movement.

  When the two-phase energization of U → V is performed, if the N pole of the rotor 15 is at a position near 150 degrees, the induced voltage polarity is determined as either positive or negative. When the induced voltage polarity is determined to be positive in step 30, the positioning process of step 50 is performed, and when the induced voltage polarity is determined to be negative, the positioning process of step 40 is performed. Is surely done. In the positioning process described in Patent Document 1, the rotational movement range of the rotor may be increased depending on the initial position of the rotor. On the other hand, in this embodiment, the rotor 15 has a maximum of 150 degrees (5π / 6 radians), an efficient positioning process that suppresses the rotational movement range of the rotor 15 is performed.

  So far, as an example of two-phase energization, the estimated range and positioning angle when the U-phase winding 11 is energized from the V-phase winding 12 and the open phase is the W-phase have been described. Needless to say, the method of driving the phase DC motor is a method that can be implemented by other two-phase energization modes. The chart shown in FIG. 8 shows the correspondence between various two-phase energizations that can be performed, the estimated range of the rotor 15, and the range of the positioning process.

  As shown in FIG. 8, in the case of U → W two-phase energization, the S pole formed in the armature 14 is at a position of 30 degrees, the open phase is the V phase, and the estimation when the induced voltage polarity is positive is assumed. The ranges are 300 to 360 degrees, 0 to 30 degrees, and 120 to 210 degrees, and the positioning angle is set to a range of 30 to 120 degrees. The estimated ranges when the induced voltage polarity is negative are 30 to 120 degrees and 210 to 300 degrees, and the positioning angles are set to the ranges of 300 to 360 degrees and 0 to 30 degrees.

  In the case of two-phase energization of V → W, the S pole formed in the armature 14 is at a position of 90 degrees, the open phase is the U phase, and the estimated range when the induced voltage polarity is positive is 90 degrees to The positioning angle is set in the range of 0 degrees to 90 degrees at 180 degrees and 270 degrees to 360 degrees. Further, the estimated ranges when the induced voltage polarity is negative are 0 ° to 90 ° and 180 ° to 270 °, and the positioning angle is set to a range of 90 ° to 180 °.

  In the case of two-phase energization of V → U, the S pole formed in the armature 14 is at a position of 150 degrees, the open phase is the W phase, and the estimated range when the induced voltage polarity is positive is 60 degrees to The positioning angle is set in the range of 150 degrees to 240 degrees at 150 degrees and 240 degrees to 330 degrees. In addition, the estimated ranges when the induced voltage polarity is negative are 330 degrees to 360 degrees, 0 degrees to 60 degrees, and 150 degrees to 240 degrees, and the positioning angle is set to a range of 60 degrees to 150 degrees.

  In the case of W → U two-phase energization, the S pole formed in the armature 14 is at a position of 210 degrees, the open phase is the V phase, and the estimated range when the induced voltage polarity is positive is 30 degrees to The positioning angle is set in the range of 120 degrees to 210 degrees at 120 degrees and 210 degrees to 300 degrees. In addition, the estimated ranges when the induced voltage polarity is negative are 300 degrees to 360 degrees, 0 degrees to 30 degrees, and 120 degrees to 210 degrees, and the positioning angle is set to a range of 210 degrees to 300 degrees.

  Further, in the case of W → V two-phase energization, the S pole formed in the armature 14 is at a position of 270 degrees, the open phase is the U phase, and the estimated range when the induced voltage polarity is positive is 0 degree to The positioning angle is set in the range of 270 degrees to 360 degrees at 90 degrees and 180 degrees to 270 degrees. The estimated ranges when the induced voltage polarity is negative are 90 to 180 degrees and 270 to 360 degrees, and the positioning angle is set to a range of 180 to 270 degrees.

  As described above, the brushless three-phase DC motor driving method and the driving control apparatus can perform the six types of two-phase energization processes. The start control described with reference to FIG. 3 can be applied to any of the above-described six two-phase energization processes on the condition that the estimated range and positioning angle shown in FIG. 8 are followed.

  FIG. 9 is a voltage waveform showing the relationship between the terminal voltage VW of the open phase, the virtual neutral point voltage VN, and a half voltage of the DC voltage VDC when the PWM control is not performed. In the present embodiment, various two-phase energizations are performed by PWM control. For example, when PWM control is not performed, the induced voltage and the reference voltage in step 20 described above are obtained from each voltage waveform shown in FIG. There is no problem even if detection is performed at an arbitrary timing.

  On the other hand, when the PWM control is performed in the two-phase energization, the induced voltage and the reference voltage can be detected at an arbitrary timing as long as the reference voltage is a virtual neutral voltage. However, since ringing (vibration waveform) occurs immediately after the PWM control is turned on, the comparator detects the induced voltage and the reference voltage after a predetermined time has elapsed since the PWM control was turned on in Step 20, and the control circuit The processing is executed so as to output the position detection signal to 50. The predetermined time is set within a range from the time when the oscillation of the terminal voltage converges until the time when the PWM control changes to OFF after the PWM control is turned on. According to this, since the induced voltage can be detected while avoiding the vibration waveform that is likely to occur immediately after the PWM control is turned on, the position of the rotor 15 can be detected smoothly and quickly.

  In the case of PWM control, ringing occurs immediately after the gate signal PWM-controlled by the inverter circuit 70 is turned on. For this reason, as shown in FIG. 10B, immediately after the gate signal is switched from ON to OFF in step 20 (immediately after switching from ON to OFF), the comparator detects the induced voltage and the reference voltage and is positioned in the control circuit. It is preferable to execute processing so as to output a detection signal. This is because the terminal voltage can be detected immediately after the gate signal is turned on, so that the terminal voltage can be detected immediately after the gate signal is turned off. Therefore, the induced voltage can be detected while avoiding the response delay of the actual terminal voltage waveform with respect to the gate signal, so that the position of the rotor 15 can be detected smoothly and quickly.

  When the PWM control is performed in the two-phase energization and the half voltage of the DC voltage VDC is adopted as the reference voltage, the induced voltage and the reference voltage can be detected only when the terminal voltage of each phase is ON. However, similarly to the above, when PWM control is performed, ringing (vibration waveform) occurs immediately after the PWM control is turned on. Therefore, after the predetermined time elapses after the PWM control is turned on in Step 20, The comparator detects the induced voltage and the reference voltage, and executes processing so as to output a position detection signal to the control circuit 50. The predetermined time is set within a range from the time when the oscillation of the terminal voltage converges until the time when the PWM control changes to OFF after the PWM control is turned on. Further, when the voltage of ½ of the DC voltage VDC is adopted as the reference voltage, the comparator immediately after the gate signal is turned from ON to OFF in Step 20 (immediately after switching from ON to OFF), as described above. It is preferable to detect the induced voltage and the reference voltage and execute processing so as to output a position detection signal to the control circuit 50.

  The effects brought about by the first embodiment will be described below. In the brushless three-phase DC motor driving method, in the position detection step corresponding to steps 20 and 25, the non-energized phase winding (W-phase winding 13) is positioned according to the comparison result between the induced voltage and the reference voltage. A first angle range from the reference position to a position where the rotation angle is displaced by π / 2 radians in either the rotation direction X or the reverse rotation direction Y, and a second angle that is point-symmetric with the first angle range about the rotation center Is estimated as the magnetic pole position of the rotor 15. Furthermore, in the position determination step corresponding to step 30, the positioning angle of the rotor 15 is determined within an angle range that is not included in the detected estimation range and is an angle that is within π / 2 radians.

  According to this, in the position detection step, the estimated range including the predetermined angle range defined with reference to the position corresponding to the non-energized phase winding is detected as the magnetic pole position of the rotor 15, and the position determination step The positioning angle of the rotor 15 is determined within an angle range that is not included in the estimation range and is an angle that is within an angle of π / 2 radians. For this reason, the positioning angle for positioning the rotor 15 before activation is determined to be a rotation angle that is less than a half rotation with respect to the magnetic pole position of the rotor 15 in a stopped state (for example, 150 degrees at the maximum). Can do. Thereby, the amount of angular displacement of the rotor 15 from the initial position in the stopped state to the positioning position before activation can be suppressed. Thus, since the angular displacement amount of the rotor 15 is small, the positioning operation of the rotor 15 is quickly converged. Therefore, a driving method that can shorten the time required to start the motor 10 is obtained.

  In addition, according to the prior art described in Patent Document 1, since the positioning process is performed twice, the rotational angle amount of the rotor in the positioning process may increase. Therefore, according to the present embodiment, in order to determine an appropriate positioning angle based on the estimated range, as described above, the amount of rotation angle of the rotor in the positioning process is small and can be suppressed to about 150 degrees at the maximum. Therefore, the processing time before starting the motor can be significantly shortened.

  In addition, when the initial position of the rotor 15 in the stopped state is shifted by 180 degrees with respect to the position to be positioned (in the case of a dead point), the rotor 15 has a certain rotational load and is difficult to rotate. In addition, the positioning process of the rotor 15 can be performed by a rotational displacement amount of a rotation angle (in this embodiment, a maximum of 150 degrees) less than a half rotation from the initial position.

  Further, in the position determination step described above, the positioning angle is displaced by π / 6 radians from the position corresponding to the magnetic pole formed in the armature when the two-phase energization is performed in either the rotational direction X or the reverse rotational direction Y. The position is determined. In addition, although the magnetic pole formed in the said armature 14 is a south pole in the above-mentioned embodiment, it may be a north pole.

  According to this, the positioning angle of the rotor 15 in the position determination step is either the rotational direction X or the reverse rotational direction Y from the position corresponding to the magnetic pole (S pole or N pole) of the armature 14 when the two-phase energization is performed. On the other hand, the position is determined to be displaced by π / 6 radians. As a result, the magnetic pole of the rotor 15 is positioned at the magnetic pole position that is easily formed by energizing the three-phase winding, so that the rotation operation can be quickly converged, and the time required for convergence to the positioning position. Can be further shortened.

  The drive control device 1, 1A for the brushless three-phase DC motor includes an induced voltage generated in the non-energized phase winding when the three-phase winding is energized in two phases prior to starting the brushless three-phase DC motor from a stopped state. Position detection means (control circuit 50) for detecting the magnetic pole position of the rotor 15 based on the result of comparison with the reference voltage, and positioning angle of the rotor based on the magnetic pole position of the rotor 15 detected by the position detection means. Position determining means (control circuit 50) for determining the position, and positioning processing for energizing the phase windings 11, 12, 13 to be energized in order to position the rotor 15 at the positioning angle determined by the position determining means Means (voltage application unit 20).

  Further, the position detection means (control circuit 50) changes π / in either the rotational direction X or the reverse rotational direction Y from the reference position where the non-energized phase winding is located according to the comparison result of the induced voltage and the reference voltage. An estimated range including a first angle range up to a position where the angle is displaced by 2 radians and a second angle range that is point-symmetric with the first angle range about the rotation center is detected as the magnetic pole position of the rotor 15. To do. Further, the position determining means (control circuit 50) determines the positioning angle of the rotor 15 within an angle range that is not included in the detected estimation range and is an angle range within π / 2 radians.

  According to this, the position detecting means detects the estimated range including the predetermined angle range determined with reference to the position corresponding to the non-energized phase winding as the magnetic pole position of the rotor 15, and the position determining means The positioning angle of the rotor 15 is determined within an angle range that is not included in the estimation range and is an angle that is within an angle of π / 2 radians. For this reason, the positioning angle for positioning the rotor 15 before activation can be determined to be a rotation angle that is less than a half rotation of 150 degrees at the maximum with respect to the magnetic pole position of the rotor 15 in the stopped state. Thereby, the angular displacement amount of the rotor 15 from the initial position in the stopped state to the positioning position before starting is suppressed with respect to the rotational displacement amount of the rotor when the half rotation by the technique of the above-mentioned Patent Document 1 is exceeded. In addition, the amount of angular displacement may be smaller than that of the prior art, and the positioning operation of the rotor 15 is likely to converge. Therefore, according to the drive control devices 1 and 1A for the brushless three-phase DC motor, it is possible to shorten the time required for starting the motor.

  Further, the position determining means (control circuit 50) sets the positioning angle to either the rotational direction X or the reverse rotational direction Y from the position corresponding to the magnetic pole formed on the armature 14 when two-phase energization is performed. The position is determined to be displaced by / 6 radian angle. In addition, although the magnetic pole formed in the said armature 14 is a south pole in the above-mentioned embodiment, it may be a north pole.

  According to this, the positioning angle of the rotor 15 by the position determining means is either the rotational direction X or the reverse rotational direction Y from the position corresponding to the magnetic pole (S pole or N pole) of the armature 14 when the two-phase energization is performed. On the other hand, the position is determined to be displaced by π / 6 radians. As a result, the magnetic pole of the rotor 15 is positioned at the magnetic pole position that is easily formed by energizing the three-phase winding, so that the rotation operation can be quickly converged, and the time required for convergence to the positioning position. Can be further shortened.

(Second Embodiment)
In the second embodiment, a modification to the startup control process of the brushless three-phase DC motor described in the first embodiment according to FIG. 3 will be described with reference to FIG. FIG. 11 is a flowchart for explaining start-up processing of the brushless three-phase DC motor in the second embodiment.

  The start control flow of the present embodiment differs from the flow described with reference to FIG. 3 in the first embodiment in that step 5 which is a preliminary energization process is executed before the two-phase energization process of step 10. Yes. In FIG. 11, steps denoted by the same numbers as those in FIG. 3 execute the same processing.

  As shown in FIG. 11, step 5 is a preliminary energization process that is performed before the two-phase energization process (step 10). In this pre-energization process, the U-phase winding 11 and the V-phase winding 12 are formed so that the S pole is formed at a position that is displaced by 60 degrees (π / 3 radians) in the rotation direction X from the U-phase. Energization (U, V → W energization) is performed to pass a current from W to the W-phase winding 13. In the energization process of U, V → W, the control circuit 50 performs switching control to turn on the FET 71 (SU +), FET 72 (SV +), and FET 76 (SW−) via the drive circuit 30. Due to the magnetic field formed by this energization, the magnetic pole (N pole) of the rotor 15 starts to rotate toward the position of 60 degrees from the initial position in the stopped state. Furthermore, the energization time in step 5 is shorter than the energization time associated with the positioning process in steps 40 and 50 and is as short as possible. The reason why the process is performed in such a short time is that the step 5 is a pre-process that is performed to facilitate the rotation of the rotor 15 toward a predetermined position of the south pole formed by the subsequent two-phase energization. Accordingly, the preliminary energization in step 5 plays a role if the rotor 15 starts to rotate even a little.

  Note that the ON / OFF control of the switching element in the preliminary energization in step 5 is set so that the rotor 15 is directed to the position of the S pole corresponding to the position of the S pole set in the subsequent two-phase energization. Is. Further, the preliminary energization as in step 5 before the two-phase energization may be performed a plurality of times and in a shorter time per one time.

  According to the driving method of the brushless three-phase DC motor of the second embodiment, prior to the two-phase energization process (step 10), the pre-energization for supplying a current in a predetermined direction to the three-phase winding is performed in the positioning process step ( There is a preliminary energization step (step 5) performed in a shorter time than the energization time performed in step 40 and step 50).

  According to this, by carrying out preliminary energization before the two-phase energization processing and rotating the rotor 15 even a little from the stopped state, the rotational load of the rotor 15 becomes large at the start of the two-phase energization, and the rotor becomes Even when it is difficult to rotate (for example, when the magnetic pole position is at a dead point where the magnetic field is difficult to work), the rotor 15 starts to rotate by the pre-energization process and the rotational load is reduced. The child 15 can be rotated reliably and smoothly. Therefore, the speed of the position detection process of the rotor 15 and the positioning accuracy are improved, which can contribute to shortening the time until the motor is started.

(Third embodiment)
In the third embodiment, a modification to the startup control process of the brushless three-phase DC motor described in the first embodiment according to FIG. 3 will be described with reference to FIG. FIG. 12 is a flowchart for explaining start-up processing of the brushless three-phase DC motor in the third embodiment.

  The activation control flow of the present embodiment is the same as the flow described with reference to FIG. 3 in the first embodiment, except that step 31 which is a preliminary energization process is executed before the positioning process of step 40 and the positioning of step 50 is performed. The difference is that step 32, which is a preliminary energization process, is executed before the process. In FIG. 12, steps denoted by the same numbers as those in FIG. 3 execute the same processing.

  As shown in FIG. 12, step 31 is a preliminary energization process performed before the positioning process (step 40). In the pre-energization process in step 31, the U-phase winding 11 and the V-phase winding are formed so that the S pole is formed at a position where the armature 14 is angularly displaced by 60 degrees (π / 3 radians) from the U phase in the rotation direction X. Energization (U, V → W energization) is performed such that a current flows from the wire 12 to the W-phase winding 13. In the energization process of U, V → W, the control circuit 50 performs switching control to turn on the FET 71 (SU +), FET 72 (SV +), and FET 76 (SW−) via the drive circuit 30. Due to the magnetic field formed by this energization, the magnetic pole (N pole) of the rotor 15 starts to rotate toward the position of 60 degrees from the initial position in the stopped state. Furthermore, the energization time in step 31 is shorter than the energization time associated with the positioning process in step 40 and is as short as possible. The reason why the process is performed in such a short time is that the step 31 is a pre-process for starting the rotation of the rotor 15 toward a predetermined position of the S pole formed in the subsequent positioning process. Accordingly, the preliminary energization in step 31 plays a role if the rotor 15 starts to rotate even a little. The preliminary energization as in step 31 before the positioning process may be performed a plurality of times and in a shorter time per time.

  Similarly, step 32 is a preliminary energization process performed before the positioning process (step 50). In the pre-energization process in step 32, the U-phase winding 13 is wound from the W-phase winding 13 so that the S pole is formed at a position displaced by 240 degrees (4π / 3 radians) in the rotational direction X from the U-phase. Energization (W → U, V energization) is performed to pass current through the wire 11 and the V-phase winding 12. In the energization process of W → U, V, the control circuit 50 performs switching control so that the FET 73 (SW +), the FET 74 (SU +), and the FET 75 (SV−) are turned on via the drive circuit 30. Due to the magnetic field generated by this energization, the magnetic pole (N pole) of the rotor 15 starts to rotate from the initial position in the stopped state toward a position of 300 degrees. Furthermore, the energization time in step 32 is shorter than the energization time associated with the positioning process in step 50 and is as short as possible. The reason why the process is performed in such a short time is that the step 32 is a pre-process that is performed in order to start turning the rotor 15 toward a predetermined position of the south pole formed in the subsequent positioning process. Therefore, the preliminary energization in step 32 plays a role if the rotor 15 starts to rotate even slightly. The preliminary energization as in step 32 before the positioning process may be performed a plurality of times and in a shorter time per time.

  According to the driving method of the brushless three-phase DC motor of the third embodiment, prior to the positioning process steps (steps 40 and 50), the preliminary energization for passing a current in a predetermined direction to the three-phase winding is positioned. There is a preliminary energization step (steps 31 and 32) that is performed in a shorter time than the energization time performed in step (b).

  According to this, preliminary energization is performed before the positioning process, and the rotor 15 is rotated even a little from the stopped state, so that the rotation load of the rotor 15 is large at the start of the positioning process, and the rotor is difficult to rotate. Even in a case (for example, when the magnetic pole position is at a dead point where the magnetic field is difficult to work), the rotor 15 starts to rotate by pre-energization and the rotational load is reduced. Therefore, the rotation operation of the rotor 15 is performed during the positioning process. It can be performed reliably and smoothly. Therefore, speeding up of the positioning process of the rotor 15 and positioning accuracy are improved, which can contribute to shortening the time until the motor is started.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The brushless three-phase DC motor described in the above embodiment is applied to various electric fans, air conditioner blowers, hard disk drives, CD (compact disc) drives, DVD (digital versatile disc) drives, etc. in addition to fuel pumps. Can do.

  In the fuel pump, it is necessary to increase the fuel pressure before the crankshaft rotates 90 degrees in order to start from the ignition switch ON and restart from the idling stop. In a brushless three-phase DC motor that performs sensorless drive control, if positioning before starting fails, it takes time to start the engine. Therefore, according to the brushless three-phase DC motor driving method and drive control apparatus of the above embodiment, positioning can be performed in a short time and with certainty, and appropriate fuel pump activation and restart from an idling stop can be realized.

  In various electric fans and blowers of air conditioners, low noise and stable starting are required. Therefore, according to the brushless three-phase DC motor driving method and drive control apparatus of the above embodiment, positioning can be performed in a short time and with certainty, and requirements for low noise and stable starting can be satisfied.

  A hard disk drive, a CD drive, and a DVD drive are required to drive with high responsiveness. Therefore, according to the brushless three-phase DC motor drive method and drive control apparatus of the above embodiment, positioning can be performed in a short time and with high reliability, and high responsiveness and high-speed processing performance can be achieved.

  Note that the brushless motor driving method and the like according to the above embodiment refer to a three-phase DC motor, but the same technical idea can be applied to a motor having four or more phases. As described above, when applied to a motor having four or more phases, in the position detection step, energization is performed for two or more phase windings among the four or more windings and energization for the remaining one or more phases. The estimated range of the magnetic pole position of the rotor can be detected based on the result of comparing the induced voltage generated in the non-energized phase winding and the reference voltage. Furthermore, in the position determination step, the positioning angle of the rotor can be determined to an angle within a predetermined range based on the estimated range.

10 ... Motor (Brushless three-phase DC motor)
11 ... U-phase winding (three-phase winding)
12 ... V-phase winding (three-phase winding)
13 ... W phase winding (three phase winding)
DESCRIPTION OF SYMBOLS 14 ... Armature 15 ... Rotor 20 ... Voltage application part (positioning process means)
40: position detection means 50 ... control circuit (position detection means, position determination means)

Claims (11)

A method for driving a brushless three-phase DC motor comprising an armature having a three-phase winding and a rotor having a permanent magnet,
Prior to starting the brushless three-phase DC motor from a stopped state, the rotation is based on a result of comparing a reference voltage with an induced voltage generated in a non-energized phase winding when the three-phase winding is energized in two phases. A position detecting step for detecting the magnetic pole position of the child;
A position determining step for determining a positioning angle of the rotor based on the detected magnetic pole position of the rotor;
A positioning process step of energizing the phase winding to be energized to position the rotor at the determined positioning angle;
Have
Wherein in the position detecting step, in response to said induced voltage and the reference voltage the comparison result, when the induced voltage polarity of the comparison result is negative electricity rotational direction from a reference position phase windings of the non-energized is located In the case of the comparison result in which the induced voltage polarity is positive in the range up to the position where the angle is displaced by π / 2 radians , the electrical angle is π / in the reverse rotation direction from the reference position where the non-energized phase winding is located. An estimated range consisting of a first angle range that is a range up to a position where the angle is displaced by 2 radians and a second angle range that is point-symmetric with the first angle range with respect to the rotation center is a magnetic pole of the rotor Detect as position,
In the position determining step, the positioning angle of the rotor is determined within an angular range that is not included in the detected estimation range and is an electrical angle within an angle of π / 2 radians. The brushless three-phase DC motor drive method. In the position determination step, the positioning angle is π / 6 radian angle in electrical angle from the position corresponding to the magnetic pole formed in the armature when the two-phase energization is performed to either the rotation direction or the reverse rotation direction. The method for driving a brushless three-phase DC motor according to claim 1, wherein the position is determined to be displaced.   Prior to the two-phase energization performed before the position detection step, preliminary energization for flowing a current in a predetermined direction to the three-phase winding is performed in a shorter time than the energization time performed in the positioning processing step. 3. The method of driving a brushless three-phase DC motor according to claim 1, further comprising a preliminary energization step.   Before the positioning process step, there is a preliminary energization step in which pre-energization for flowing a current in a predetermined direction to the three-phase winding is performed in a shorter time than the energization time performed in the positioning process step. The brushless three-phase DC motor driving method according to claim 1 or 2.   The position detecting step detects the induced voltage after a predetermined time has elapsed since the pulse width modulation control was turned on when the two-phase energization is performed by pulse width modulation control. The method for driving a brushless three-phase DC motor according to any one of claims 1 to 4.   In the position detection step, when the two-phase energization is performed by pulse width modulation control, the induced voltage is detected immediately after the gate signal based on the pulse width modulation control is turned off from on. The driving method of the brushless three-phase DC motor according to any one of claims 1 to 4.   The method for driving a brushless three-phase DC motor according to any one of claims 1 to 6, wherein the reference voltage is a voltage corresponding to half of a virtual neutral point voltage or a power supply voltage.   The method of driving a brushless three-phase DC motor according to any one of claims 1 to 7, wherein the brushless three-phase DC motor is an actuator of a fuel pump. A drive control device for a brushless three-phase DC motor for controlling the driving of a brushless three-phase DC motor comprising an armature having a three-phase winding and a rotor having a permanent magnet,
Prior to starting the brushless three-phase DC motor, the magnetic pole position of the rotor is based on the result of comparing the induced voltage generated in the non-energized phase winding and the reference voltage when the three-phase winding is energized in two phases. Position detecting means for detecting
Position determining means for determining a positioning angle of the rotor based on a magnetic pole position of the rotor detected by the position detecting means;
Positioning processing means for energizing a phase winding to be energized to position the rotor at the positioning angle determined by the position determining means;
With
Said position detecting means, in response to the comparison result of the induced voltage and the reference voltage, when the induced voltage polarity is negative is that the comparison result electrically in the direction of rotation from the reference position phase windings of the non-energized is located In the case of the comparison result in which the induced voltage polarity is positive in the range up to the position where the angle is displaced by π / 2 radians , the electrical angle is π / in the reverse rotation direction from the reference position where the non-energized phase winding is located. An estimated range consisting of a first angle range that is a range up to a position where the angle is displaced by 2 radians and a second angle range that is point-symmetric with the first angle range with respect to the rotation center, Detect as magnetic pole position,
The position determining means determines the positioning angle of the rotor within an angular range that is not included in the detected estimation range and is an electrical angle within an angle of π / 2 radians. A brushless three-phase DC motor drive controller. The position determining means sets the positioning angle to an electrical angle of π / 6 radians from the position corresponding to the magnetic pole formed in the armature when the two-phase energization is performed in either the rotational direction or the reverse rotational direction. The drive control device for a brushless three-phase DC motor according to claim 9, wherein the position is determined to be displaced.   The brushless three-phase DC motor drive control device according to claim 9 or 10, wherein the brushless three-phase DC motor is an actuator of a fuel pump.

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