JP2008043065A - Motor core phase adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor core phase adjusting method for rapidly executing exact phase adjustment by rotating and driving a motor core to a position other than an opposite phase of an excitation original point, preliminarily driving it to the excitation original point, and allowing an application current to be steep into a rectangular wave in a closing operation from a CW direction and a CCW direction. <P>SOLUTION: The motor core is rotated and driven in the position other than positive and opposite phases of the excitation original point, the motor core is rotated and driven to the excitation original point, the motor core is rotated and driven to the CW direction and the CCW direction symmetrically at the excitation original point from a predetermined angle, the rise of the application current at the time of rotary driving is made to be steep, and a mid-point of a driving distance of rotary driving is used as the excitation original point. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a motor core phase adjustment method for adjusting the phase of an electrical angle of a motor core based on the relationship between a coil and a magnetic pole wound around each phase of a brushless DC motor, and more particularly, to a motor core by passing a current through each phase coil. Based on the position at which no torque is generated based on the excitation origin, in the approaching operation to adjust the excitation origin, forward and reverse phase drive commands are given sequentially, and the waveform of the current applied to any coil is sharpened to drive at high speed. Therefore, the present invention relates to a motor core phase adjustment method that can set an accurate excitation origin quickly.

  The brushless DC motor detects the electrical phase of the motor core, and with the electrical angle origin (excitation origin) as a reference, the current flows through each phase coil in synchronization with the phase of the motor core (commutation). Torque can be output well. For this reason, it is necessary to detect the phase difference between the position detector and the motor core (rotor).

  Here, the structure and operation of the brushless DC motor will be described. FIG. 6 shows a cross-sectional structure of an inner rotor type three-phase brushless DC motor 10, and U-phase, V-phase, and W-phase coils 13, 14, and 15 are wound around the stator 11 with phases shifted by 120 °. The motor core 12 serving as a rotor is formed of four permanent magnets (N, S, N, S). Then, by passing an electric current through each phase coil 13-15, the motor core 12 is rotated by the attractive force between the magnetic field generated in each phase coil 13-15 and the permanent magnet 4 poles, and further in accordance with the phase of the motor core 12. The motor core 12 is continuously driven to rotate by performing commutation control on the currents of the phase coils 13 to 15. FIG. 7 shows the phase relationship of commutation of the U-phase coil 13, V-phase coil 14, and W-phase coil 15 in the case of sinusoidal drive. That is, the rotor of the motor core 12 is rotated by passing a sine wave current shifted by 120 ° through the coils 13 to 15.

  As described above, when the brushless DC motor 10 is rotationally driven by performing commutation control, torque can be generated most efficiently by flowing a three-phase current with the electric angle origin of the motor core 12 as a reference. It is necessary to know the phase difference between the position detector such as the motor core 12 accurately.

  Here, since the phase difference between the phase detector for detecting the phase of the motor core 12 and the motor core 12 does not change mechanically, the phase adjustment is performed again by adjusting the phase of the motor core 12 and setting an accurate parameter. There is no need. That is, the acquisition of the current position is normally calculated from two position signals of an absolute position resolver (coarse) and a relative position resolver (fine), and how far the phase of the motor core 12 is from the origin of the absolute position resolver. Defined as a parameter. If the phase position of the absolute position resolver and the motor core 12 is detected, it is not necessary to detect the phase position of the motor core 12 again. Similarly, when reading the pulse signal from the incremental encoder and controlling the motor core 12, it is not necessary to adjust the phase again by adjusting and setting the phase of the motor core 12. The phase adjustment of the motor core 12 when the power is turned on or when the control is started, or the phase adjustment of the motor core 12 manually is particularly important because it becomes a reference for current application in the subsequent rotation drive control. In addition, if there is no absolute position resolver or if there is a failure, if an error occurs between the absolute position resolver and the relative position resolver, or if the current application parameters have been lost, it is necessary to adjust the phase of the motor core. Become.

  As an apparatus for detecting and adjusting the phase difference between the position detector and the motor core, there is a drive unit 20 as shown in FIG. The drive unit 20 is mainly configured by a CPU 21 that performs overall control, and a drive control unit 22 controls the drive of the motor 10 based on parameters set in the setting unit 23, and the drive control unit 22 controls the three-phase coils 13 to 15. The motor 10 is driven by controlling the commutation of the current to flow. The phase of the motor core 12 of the motor 10 is detected by a resolver (absolute position resolver, relative position resolver) 18 attached to the motor 10, and the phase is measured by a measuring unit 24 based on a position signal from the resolver 18. Further, when the phase of the motor core 12 is adjusted, the measurement value measured by the measurement unit 24 is stored in the storage unit 25, the phase difference is calculated by the calculation unit 26 based on the storage data of the storage unit 25, and the calculated result is It is set as a parameter in the setting unit 23.

  Next, a conventional operation for adjusting the phase of the motor core 12 using the drive unit 20 will be described.

  As shown in FIG. 9, for example, a direct current is passed through the U-phase coil 13 by the drive control unit 22 of the drive unit 20 to rotationally drive the motor core 12, and the position where the torque generated by the motor core 12 becomes zero is the excitation origin of the motor core 12. It shows how to determine. FIG. 10 shows a state in which current flows in the coils 14 and 15 when current is passed through the U-phase coil 13 in FIG. When a current is passed through the U-phase coil 13 in this way, it should approach the excitation origin in the middle of the magnetic pole of the motor core 12, but due to the influence of the friction and rotation direction of the motor core 12, the excitation actually occurs as shown in FIG. You can only get close to the origin. For this reason, the drive control unit 22 performs an approaching operation of the motor core 12 from both the CW direction and the CCW direction, and the driving distance in each direction is measured by the measuring unit 24 and stored in the storage unit 25. The calculation unit 26 reads the driving distances from the CW direction and the CCW direction from the storage unit 25, sets the midpoint as the excitation origin, and ends the phase adjustment.

  Further, as shown in FIG. 11, the output torque when the phase of the motor core 12 is adjusted has the maximum centripetal force when the difference between the excitation origin and the current position is 90 °, and the current is reduced when the centripetal force is large. When the centripetal force is small, a large current is allowed to flow. FIG. 12 shows output torque characteristics (shaded portions) actually generated with respect to a sinusoidal applied current. The actually output torque is obtained by the product of the centripetal force and the current value, and the current is applied in a sine wave shape so that an average torque is output at any angle.

  The manner in which the phase of the motor core 12 is detected by the above-described approaching operation will be described in detail with reference to the flowchart of FIG. 13 and the schematic diagram of FIG.

  The example of FIGS. 13 and 14 is a case where the drive range of the approaching operation is set by the setting unit 23 so that the excitation origin is symmetrical and the electrical angle is 120 °. As shown in FIG. 13, assuming that the initial position of the motor core 12 is in the vicinity of an electrical angle of 20 ° (step S50), the motor core 12 is rotationally driven in the CW direction to an electrical angle of 120 ° (step S51), and from the electrical angle of 120 ° to the CCW direction. To the excitation origin (step S52). The driving distance A5 at this time is measured by the measuring unit 24 (step S53), stored in the storage unit 25, and further rotated to an electrical angle of 240 ° in the CCW direction from the excitation origin (step S54). The electrical angle is moved from the 240 ° position to the excitation origin in the CW direction (step S55). The driving distance A6 at this time is measured by the measuring unit 24 (step S56) and stored in the storage unit 25. The calculation unit 26 reads the driving distances A5 and A6 from the CW direction and the CCW direction from the storage unit 25 and calculates the midpoint (step S57), and sets the calculated midpoint of the excitation origin in the setting unit 23 ( Step S58), the phase adjustment of the motor core 12 is finished.

  However, in the brushless DC motor 10 composed of permanent magnets as described above, an electrical angle is generated when a drive command (for example, an electrical angle of 0 ° to an electrical angle of 180 °) is performed on the magnetic poles of the motor core 12 in the opposite phase. At 0 ° and an electrical angle of 180 °, the torque becomes 0, so that there is a problem that it cannot be rotated or is difficult to rotate. When power is turned on, when control is started, or when phase adjustment is performed manually, a drive command to the opposite phase may be included in the approaching operation from the CW direction and the CCW direction, which may cause a malfunction in the approaching operation. . This will be described with reference to the flowchart of FIG. 15 and the schematic diagram of FIG.

  The example of FIGS. 15 and 16 is a case where the drive range of the approaching operation is set by the setting unit 23 so that the excitation origin is symmetrically 120 °. As shown in FIG. 16, when the initial position of the motor core is at an electrical angle of 300 ° (step S60), the motor core cannot be rotationally driven to an electrical angle of 120 °, which is in the opposite phase from the CW direction (step S61). Therefore, the excitation angle is moved closer to the excitation origin from the CW direction at the electrical angle of 300 ° (step S62), and the driving distance A7 at this time is measured by the measurement unit 24 and stored in the storage unit 25 (step S63). The rotational angle is driven in the CCW direction from the origin to the electrical angle 240 ° position (step S64), and the rotationally driven electrical angle 240 ° position is brought close to the excitation origin in the CW direction (step S65). The driving distance A8 at this time is measured by the measuring unit 24 and stored in the storage unit 25 (step S66), but the calculating unit 26 sets an error because of the driving distances A7 and A8 only in the CW direction (step S67).

  Thus, in the conventional phase adjustment method, the calculated midpoint may not match the calculated electrical angle of 0 ° depending on the initial position. Furthermore, when adjusting the phase of a motor core with large frictional resistance, moment of inertia and cogging, if the close-up operation is performed when the current applied to the coil is insufficient and the output torque is not sufficient, the effects of errors due to friction etc. In some cases, it becomes large and accurate measurement cannot be performed.

  For this reason, there has been a demand for the emergence of a method for always promptly obtaining an accurate excitation origin.

  The present invention has been made under the circumstances as described above, and an object of the present invention is to position the motor core excluding the excitation origin and the excitation origin in reverse phase when adjusting the phase of the motor core with a conventional hardware configuration. After pre-driving to rotate the motor core to the excitation origin, the approaching operation from the CW direction and the CCW direction is surely performed, and the rising waveform of the current applied to any coil during the approaching operation is made steep. Accordingly, it is an object of the present invention to provide a motor core phase adjustment method capable of performing phase adjustment with high accuracy and speed.

  The present invention relates to a motor core phase adjustment method for adjusting a phase of the motor core by flowing a current through a motor coil having a motor core having a plurality of magnetic poles. The above object of the present invention is a position excluding the normal and reverse phases of the excitation origin. The motor core is rotated and driven to the excitation origin, the excitation origin is symmetrical, the motor core is rotated from a predetermined angle in the CW direction and the CCW direction, respectively, and the applied current during the rotation drive This is achieved by making the rise of the steep rise and setting the midpoint of the driving distance of the rotational drive as the excitation origin.

  Further, by setting the average value of the driving distance 1 in the CW direction and the driving distance 2 in the CCW direction as the middle point, or by making the rising of the applied current into a rectangular wave shape, or the motor is a brushless DC motor. This is achieved more effectively.

  According to the motor core phase adjustment method of the present invention, when performing the approaching operation for adjusting the phase of the motor core, considering that the motor core may not be rotationally driven in the opposite phase, the motor core is moved to the excitation origin and the opposite phase of the excitation origin. After pre-driving to rotate to the position excluding, and rotating to the excitation origin, a close-up operation from the CW direction and CCW direction is performed, and the waveform of the current applied to any coil is steep and sufficient output By adjusting the phase of the motor core based on the torque, an accurate excitation origin can always be obtained. In addition, since the rising of the applied current at the time of rotational driving is steep, high-speed driving is possible and quick phase adjustment is possible. Further, the adjustment can be easily performed by using conventional hardware as it is and changing the software.

  In the motor core phase adjustment method according to the present invention, in the case of performing a close-up operation by adjusting the phase of the motor core (rotor), an arbitrary coil is considered in consideration of a problem caused by giving a drive command to the opposite phase to the motor core. The position that approaches the excitation origin (electrical angle origin) of the motor core, which is close to the magnetic force generated by passing a current through the motor, is rotated once to a position excluding the opposite phase with respect to the excitation origin, and further driven to the excitation origin. After that, the accurate excitation origin is always obtained by measuring each driving distance of the approaching operation from both the CW and CCW directions that is reliably performed. In addition, by making the rise of the applied current flowing in any coil steep during the approaching operation, the drive distance is measured based on sufficient output torque that is output quickly, so that an accurate excitation origin can be obtained. ing.

  The method of the present invention will be described below with reference to the drawings. Further, the configuration of the apparatus for carrying out the present invention is the same as that of the conventional apparatus (FIG. 8), and the description thereof is omitted.

  An example of the operation of the present invention is as shown in the flowchart of FIG. 1 and the schematic diagram of FIG. 2. In the example of FIG. 1 and FIG. 2, the preliminary drive is rotated to an electrical angle of 300 ° and then rotated to the excitation origin. The approaching operation when the drive range of the approaching operation is set to an electrical angle of 60 ° symmetrically with respect to the excitation origin is shown.

  First, as shown in FIG. 2, preliminary driving is performed from a state where the initial position of the motor core 12 is in the vicinity of an electrical angle of 210 ° (step S10). Preliminary driving is performed by rotating the electrical angle in the CW direction to an electrical angle of 300 ° (step S11), rotationally driving from the electrical angle of 300 ° to the excitation origin (step S12), and performing an approaching operation. Next, it is rotationally driven from the excitation origin to the electrical angle 60 ° position in the CW direction (step S13), and is moved closer to the excitation origin in the CCW direction from the rotationally driven electrical angle 60 ° position (step S14). The driving distance A1 is measured by the measuring unit 24 and stored in the storage unit 25 (step S15). Then, it is rotationally driven from the excitation origin to the electrical angle 300 ° position in the CCW direction (step S16), and is moved closer to the excitation origin in the CW direction from the rotationally driven electrical angle 300 ° position (step S17). The distance A2 is measured by the measuring unit 24 and stored in the storage unit 25 (step S18). The calculation unit 26 reads the driving distances A1 and A2 from the storage unit 25 to calculate the midpoint (step S19), sets the calculated midpoint as the excitation origin in the setting unit 23 (step S20), and the phase of the motor core 12 Finish the adjustment.

  On the other hand, in the examples of FIGS. 3 and 4, the initial position is 120 ° position, and as a preliminary drive, after rotating to an electrical angle of 300 °, further rotating to the excitation origin to drive the approaching operation. The operation when the range is set to an electrical angle of 60 ° symmetrically with respect to the excitation origin is shown.

  First, as shown in FIG. 4, preliminary driving is performed from a state where the initial position of the motor core is in the vicinity of an electrical angle of 120 ° (step S30). Preliminary drive is rotationally driven at an electrical angle of 300 ° in the CCW direction. However, since it is in an opposite phase, it cannot be rotationally driven (step S31). It performs (step S32). Then, it is rotationally driven from the excitation origin to an electrical angle of 60 ° in the CW direction (step S33), and moved from the rotationally driven electrical angle of 60 ° to the excitation origin in the CCW direction (step S34). The distance A3 is measured by the measuring unit 24 and stored in the storage unit 25 (step S35). Further, it is rotationally driven from the excitation origin to the 300 ° electrical angle position in the CCW direction (step S36), and is moved closer to the excitation origin in the CW direction from the rotationally driven electrical angle position of 300 ° (step S37). Is measured by the measurement unit 24 and stored in the storage unit 25 (step S38). The calculation unit 26 reads the driving distances A3 and A4 from the storage unit 25 to calculate the midpoint (step S39), sets the calculated midpoint as the excitation origin in the setting unit 23 (step S40), and the phase of the motor core 12 Finish the adjustment.

  However, as described above, the output torque at the time of adjusting the phase of the motor core 12 is output on average regardless of the distance between the current position and the excitation origin. As you can see, it increases or decreases sinusoidally. The driving torque also increases and decreases sinusoidally, which is problematic in terms of high-speed driving. Therefore, in the present invention, the driving is performed in a rectangular wave shape with a steep rise. A characteristic example of the applied current and output torque of the present invention will be described with reference to FIG.

  The output torque and driving speed of the motor core 12 can be changed from the outside in consideration of loads and states such as the motor 10 type, friction resistance, inertia moment and cogging of the motor core 12, and the rise time (tilt angle) of the applied current. it can. For example, as shown in FIG. 5, when the applied current rises sharply in a rectangular wave shape, the output torque is also rapidly increased. As described above, when the rising of the applied current is made steep, the output torque is rapidly increased, so that the motor core 12 can be rotated rapidly, and the effective current can be increased, but abnormal heat generation can be suppressed within the rated current range. . Then, the phase adjustment of the motor core 12 can be performed at a high speed by applying the current steeply at the time of each approaching operation of FIGS.

  As described above, according to the present invention, the rotation is driven to the position excluding the excitation origin and the reverse phase of the excitation origin of the motor core that is rotationally driven based on the output torque that is sufficiently output, and then the rotation is driven to the excitation origin. After the preliminary drive, the close-up operation is performed at high speed from the CW direction and the CCW direction, and the midpoint of the drive distance is set as the electrical angle origin, so that accurate phase adjustment can always be performed quickly. .

  It should be noted that there may be one or a plurality of phases in which a current is passed in performing the pre-driving and the approaching operation as long as it acts on a specific magnetic pole of the motor core and the torque of the motor core can be made zero. Even if the positive phase is the excitation origin but the opposite phase is the origin, the motor core torque can be reduced to zero, so the same effect can be obtained. If it is multiphase, the same effect can be obtained, and it can be detected not only in U phase but also in V phase and W phase, and the number of magnetic poles of the motor core is exemplified as 4 poles. The same effect can be obtained. Further, although the inner rotor type has been described as an example of the brushless DC motor, the same effect can be obtained even with the outer rotor type.

It is a flowchart which shows the example of the motor core phase adjustment method which concerns on this invention. It is a schematic diagram which shows the example of the motor core phase adjustment method which concerns on this invention. It is a flowchart which shows the other example of the motor core phase adjustment method which concerns on this invention. It is a schematic diagram which shows the other example of the motor core phase adjustment method which concerns on this invention. It is a figure which shows the example of a characteristic of the electric current applied to the motor core which concerns on this invention, and an output torque. It is sectional drawing of the axial direction of a three-phase brushless DC motor. It is a figure which shows the phase difference of each phase of a three-phase brushless DC motor. It is a figure which shows the structural example of a drive unit. It is sectional drawing of the axial direction which shows the error which arises in a three-phase brushless DC motor. It is an equivalent circuit diagram of a three-phase brushless DC motor. It is a figure which shows the output characteristic example of the centripetal force which changes with the phase difference of a motor core. It is a figure which shows the example of a characteristic of the output torque with respect to the electric current applied to a motor core. It is a flowchart which shows an example of the phase adjustment method by the conventional close-in operation | movement. It is a schematic diagram which shows the mode of the phase adjustment by the conventional close-in operation | movement. It is a flowchart which shows the other example of the phase adjustment method by the conventional close-in operation | movement. It is a schematic diagram which shows the other example of the mode of the phase adjustment by the conventional close-in operation | movement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motor 11 Stator 12 Motor core 13 U phase coil 14 V phase coil 15 W phase coil 18 Resolver 20 Drive unit 21 CPU
22 drive control unit 23 setting unit 24 measurement unit 25 storage unit 26 calculation unit

Claims (4)

In a motor core phase adjustment method for adjusting a phase of the motor core by flowing a current through a coil of a motor having a motor core having a plurality of magnetic poles, the motor core is rotationally driven to a position excluding the normal / reverse phase of the excitation origin, and then the excitation Drive rotationally to the origin, rotate the motor core from a predetermined angle in the CW direction and the CCW direction with the excitation origin symmetrical, and steeply rise the applied current during the rotational drive to drive the rotational drive A motor core phase adjusting method, wherein a midpoint of a distance is set as the excitation origin. The motor core phase adjustment method according to claim 1, wherein an average value of the driving distance 1 in the CW direction and the driving distance 2 in the CCW direction is the midpoint. The motor core phase adjusting method according to claim 1 or 2, wherein the rising edge of the applied current is rectangular. The motor core phase adjusting method according to claim 1, wherein the motor is a brushless DC motor.

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