JP2008043066A - Motor core phase adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor core phase adjusting method for 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, rapidly and positively executing a closing operation from a CW direction and a CCW direction at a high speed, and preventing an overheat of a motor. <P>SOLUTION: The motor core is rotated and driven to 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, and the motor core is rotated and driven in the CW direction and the CCW direction symmetrically at the excitation original point from a predetermined angle. In this case, the rotary driving is executed while switching usual driving for applying a current of not more than a rated current of the motor and high-speed driving for applying a current more than the rated current, and a mid-point of a driving distance of the 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. The excitation origin is set at a position where no torque is generated based on the excitation origin, and a current exceeding the motor rated current is applied to the close-up operation for adjusting the excitation origin, so that the excitation origin is set accurately and quickly without overheating. The present invention relates to a motor core phase adjustment method that can be set.

  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.

  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. 11 and the schematic diagram of FIG.

  The example of FIGS. 11 and 12 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.

  Normally, such an approaching operation of the motor 10 is performed by applying a current to an arbitrary coil of the motor 10 within a range of the rated current.

  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. 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 symmetrically 120 °. As shown in FIG. 14, assuming that 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 ° that 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.

  In addition, when adjusting the phase of a motor core that is greatly affected by frictional resistance, moment of inertia and cogging, if a close-up operation is performed when the current applied to the coil is insufficient and the output torque is not sufficient, errors due to friction, etc. In some cases, accurate measurement cannot be performed. For this reason, in situations where it is necessary to adjust the current more than the rated current at high speed and accurately, if a current exceeding the rated current is applied continuously, the motor will generate heat, and overheating will cause a malfunction. .

  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. It is to provide a motor core phase adjusting method that reliably and rapidly moves from the CW direction and the CCW direction after the preliminary driving of rotating the motor core to the excitation origin and performing the approaching operation from the CW direction and the CCW direction.

  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. When the motor core is rotated and driven to the excitation origin, the excitation origin is symmetric, and the motor core is rotated from a predetermined angle in the CW direction and the CCW direction, respectively. This is achieved by switching between normal driving for applying a current and high speed driving for applying a current exceeding the rated current, and setting the midpoint of the driving distance of the rotational drive as the excitation origin.

  Further, by performing the high-speed driving with respect to the approaching operation to the excitation origin, or 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 midpoint, or This is achieved more effectively when the motor is a brushless DC motor.

  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 drive to the excitation origin and rotating to the excitation origin, perform the approach operation from the CW direction and CCW direction, and apply a current higher than the motor rated current only when approaching the excitation origin. In other cases, it is possible to suppress the heat generation of the motor by applying a current equal to or lower than the rated current and always obtain the excitation origin accurately and at high speed. 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 approached by the magnetic force generated by passing a current through the motor, is rotated once to a position excluding the reverse 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 adjusting the applied current, only when it is moved closer to the excitation origin, a more accurate excitation origin can be set based on sufficient output torque that applies a current higher than the rated current and a movement operation that suppresses heat generation. I want to ask.

  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 electrical angle 300 ° 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 300 ° position (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, when the frictional resistance, the moment of inertia and the cogging of the motor core 12 are large, the accurate driving distance cannot be measured if the output torque is insufficient. In order to obtain torque, the driving is performed at a high speed that applies a current exceeding the rated current, and the applied current is kept within the rated current range for normal driving that does not require measurement accuracy. Switching between high-speed driving and other normal driving during the approaching operation of the present invention will be described with reference to the characteristic diagram of FIG.

  In FIG. 5, as an example, only for high-speed driving that rotates to the excitation origin, the applied current is doubled the motor rated current, and all driving other than rotation driving to the excitation origin is kept within the rated current range. This shows how to suppress excessive heat generation. Also, as an example, a current that is twice the motor rated current is applied to all rotational drives (one-dot chain line), and a current that is twice the motor rated current is applied only to high-speed driving that is rotationally driven to the excitation origin. (Solid line) is shown. Next, the operation will be described below with reference to steps S11 to S17 of the flowchart of FIG. 1 and the schematic diagram of FIG.

  From the state near the initial position of 210 °, it is rotationally driven in the CW direction to an electrical angle of 300 ° (step S11). At this time, heat generation is suppressed by applying a rated current to the V phase. Then, it is rotationally driven from the position of 300 ° electrical angle to the excitation origin (step S12). At this time, a current twice as large as the rated current is applied to the U phase, and it is brought close to the excitation origin reliably and at high speed. Then, it is rotationally driven from the excitation origin to an electrical angle position of 60 ° in the CW direction (step S13), and heat generation is suppressed by applying the rated current at this time to the W phase. Close to the excitation origin in the CCW direction from the rotationally driven electrical angle of 60 ° (step S14). At this time, twice the rated current is applied to the U phase, and it is reliably and rapidly brought close to the excitation origin. The driving distance A1 is measured by the measuring unit 24 and stored in the storage unit 25. Then, it is rotationally driven from the excitation origin to the electrical angle 300 ° position in the CCW direction (step S16), and at this time, the rated current is applied to the V phase to suppress heat generation. Close to the excitation origin in the CW direction from the rotationally driven electrical angle position of 300 ° (step S17), and apply a current twice the rated current at this time to the U phase to reliably and quickly approach the excitation origin. The driving distance A2 is measured by the measuring unit 24 and stored in the storage unit 25.

  In other words, current that exceeds the rated current is applied for high-speed driving that requires a large output torque, and current that is lower than the rated current is applied for normal driving that is sufficient even if the output torque is small, thereby minimizing heat generation. Try to suppress. As described above, by controlling the magnitude of the applied current when adjusting the phase of the motor core, it is possible to output an output torque corresponding to the situation. Note that the current during high-speed driving does not have to be twice the motor rated current, and may be any current that exceeds the rated current.

  As described above, according to the present invention, the motor core is rotationally driven to a position excluding the excitation origin and the reverse phase of the excitation origin, and then the preliminary drive for rotationally driving to the excitation origin is performed, and then from the CW direction and the CCW direction. In addition to performing the close-up operation, the current applied during the close-up operation is output to exceed the rated current when necessary, and when it is not necessary, it is output within the rated current range to suppress heat generation and always accurate. Phase adjustment can be performed.

  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 an example of the characteristic of the electric current applied based on this invention. 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 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 When rotating the motor core from a predetermined angle in a CW direction and a CCW direction with the excitation origin being symmetric with respect to the excitation origin, normal driving for applying a current equal to or less than the motor rated current and exceeding the rated current are performed. A motor core phase adjustment method characterized by switching between high-speed driving for applying current and switching, and using the midpoint of the driving distance of the rotational driving as the excitation origin. The motor core phase adjustment method according to claim 1, wherein the high-speed driving is performed with respect to an approaching operation to the excitation origin. The motor core phase adjustment method according to claim 1 or 2, 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, wherein the motor is a brushless DC motor.

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