WO2019159311A1 - Dcモータの制御装置 - Google Patents
Dcモータの制御装置 Download PDFInfo
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- WO2019159311A1 WO2019159311A1 PCT/JP2018/005399 JP2018005399W WO2019159311A1 WO 2019159311 A1 WO2019159311 A1 WO 2019159311A1 JP 2018005399 W JP2018005399 W JP 2018005399W WO 2019159311 A1 WO2019159311 A1 WO 2019159311A1
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- phase
- motor
- hall element
- rotation
- absolute
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
- G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
- G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
- H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
- H02K11/21—Devices for sensing speed or position, or actuated thereby
- H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/12—Monitoring commutation; Providing indication of commutation failure
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
- H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
Definitions
- the present invention relates to a DC motor control device, and more particularly to a DC motor control device suitable for servo control that operates a DC motor that drives a driven body at a target speed and a target position.
- DC motors have a relatively simple structure and stable performance, and are inexpensive, they are widely used in a variety of fields as drive sources for various control systems such as automotive accessories. ing.
- Patent Document 1 as a DC motor control device invented by the present inventor, MR is applied to a rotating shaft based on the relationship between positioning information from an MR sensor unit having a pair of MR sensors and a motor drive signal. Acquires the sensor origin position (Z ⁇ ) information, sets the absolute origin position of the motor rotation axis, and converts all data of the A phase, B phase, and relative origin position information into absolute signal data Thus, an invention for recording in an EEPROM is disclosed.
- Patent Document 2 includes, as an absolute position encoder, a permanent magnet and first and second magnetic sensors opposed to the permanent magnet, and the first magnetic sensor is provided with two holes provided at a mechanical angle of 90 degrees apart.
- the second magnetic sensor has three hall elements for U, V, and W phases that are separated by 30 degrees in mechanical angle, and detects the absolute angular position of the rotating shaft. Disclosed inventions are disclosed.
- the invention of Patent Document 2 further includes an incremental encoder positioned on the outer side in the radial direction of the rotating shaft.
- Patent Document 3 includes two sets of Hall ICs provided with a pair of Hall elements whose output values have an inverse correlation, a control device and a communication unit, and an added value of the pair of Hall elements.
- a sensor device capable of determining an abnormality of the Hall element from the state is disclosed.
- Patent Document 1 since a pair of MR sensors are used as encoders, the reliability of the sensors is high, but the cost is higher than when only Hall elements are used as encoder sensors. There is a problem.
- the invention described in Patent Document 2 includes, as an absolute angular position detection device, an absolute position encoder provided on the end surface side of the rotating shaft, and an incremental encoder provided on the radially outer side of the rotating shaft. As a result, the configuration is complicated.
- the output values of the four Hall elements are calculated, and the torsion angle of the torsion bar is calculated based on at least one of them.
- Patent Document 3 does not disclose consideration for compensating for the low reliability of the Hall element as a sensor.
- An object of the present invention is to provide a DC motor control device capable of generating highly accurate position information as an multi-turn / absolute position encoder using an output signal of an inexpensive Hall element.
- Another object of the present invention is to provide a DC motor control device that can continue backup control with relatively high accuracy by the output of the Hall element even when the multi-rotation / absolute position encoder fails.
- a control unit that generates and outputs a drive signal and controls power supplied to each of the three-phase stator coils of the U-phase, V-phase, and W-phase of the brushless DC motor;
- a control device for a brushless DC motor having one encoder for detecting rotation of a rotor having a multipolar permanent magnet, The encoder is fixed to one end of the rotating shaft of the rotor and is a pair of radially magnetized flat magnets having an N-pole region and an S-pole region, and the motor at a position facing the magnet.
- the two sets of Hall element groups include a first Hall element group in which three Hall elements are arranged at equal intervals on a single circumference centered on the rotation center of the rotation axis, and the first Hall element group.
- the control unit uses the position on the boundary line between the N-pole region and the S-pole region of the magnet as a magnet origin position, and based on the outputs of the two sets of Hall element groups, the A phase associated with the rotation of the rotating shaft, A function for generating and outputting a B phase signal, a function for generating information on the origin position of the magnet, and a function for generating each phase information of the U phase, V phase, and W phase in accordance with the number of poles of the rotor And the drive signal based on the synchronous relationship between the relationship between the magnetic poles and currents of each field coil of the stator of the brushless DC motor and the rising phase of the A-phase or B-phase output signal corresponding to zero of the drive signal
- the Hall elements of the first and second Hall element groups have the same specifications, and the control unit performs the first operation for each rotation of the rotating shaft.
- An average value (h 1 -avg.) Of the outputs of the three Hall elements constituting one Hall element group is calculated and outputted, and the output of the three Hall elements constituting the second Hall element group is calculated.
- the average value of the output of the first Hall element group, and the average value of the output of the second Hall element group, respectively It has a function of generating and outputting A-phase and B-phase signals accompanying rotation.
- the hall elements of the first and second hall element groups have the same specifications, and the control unit is configured to make the hall elements H per rotation. If any one of the output pulses 1 -H 3 is outside the preset threshold range, it is determined that the Hall element is abnormal, a function of outputting a sensor abnormality signal, and the normal Hall element group If there is, there is a function of performing backup control based on the output.
- control unit compares the absolute signals based on the outputs of the first and second Hall element groups, and if a difference value between the two absolute signals exceeds an allowable value. And a function of determining that the motor is abnormal and a function of performing backup control based on an output of the Hall element group when there is a normal Hall element group.
- these features make it possible to generate relatively high-precision position information consisting of two sets of multi-rotation absolute signals having substantially the same value. Therefore, it is possible to provide an inexpensive and highly reliable DC motor control device that can smoothly perform backup control even when the first Hall element group or the second Hall element group of the rotation sensor fails.
- the present invention can also be applied to a DC motor with a brush.
- a DC motor control device that is inexpensive, highly reliable, and easy to determine the failure of a brushed DC motor.
- control apparatus for a DC motor that can generate information on multi-rotation / absolute position at a low cost and with high reliability while using an output signal of an inexpensive Hall element as an encoder.
- FIG. 2B is a cross-sectional view taken along the line BB of FIG. 2A, showing a configuration example of a stator and a rotor of the brushless DC motor.
- FIG. 2A shows the structural example of an encoder.
- FIG. 2A shows the structural example of an encoder.
- FIG. 2A shows the structural example of an encoder.
- FIG. 2A shows the structural example of an encoder.
- FIG. 2A shows the structural example of the drive circuit of the brushless DC motor in 1st Example.
- FIG. 2B It is a flowchart which shows the detail of the absolute rotation information generation process at the time of the initialization process shown in FIG. It is a figure which shows the concept of the relationship between a PWM signal and the output of an encoder at the time of an initialization process, and a synchronous process. It is a figure which shows the relationship between the magnetic pole of each field coil of a stator, the electric current, and the relationship of a counter electromotive force in the motor provided with the rotor of FIG. 2B. It is a time chart for explaining the process of determining the absolute origin position of the rotation axis (Z 0) for the motor drive signal. It is a flowchart which shows the detail of the absolute rotation information generation process at the time of normal operation mode in 1st Example.
- FIG. 1 is a functional block diagram of a laciless DC motor provided with a control device according to the first embodiment of the present invention.
- the brushless DC motor 10 (hereinafter simply referred to as the motor 10) is an inner rotor type three-phase brushless DC servo motor.
- As the motor main body 100 a permanent magnet type rotor integrally formed with the rotary shaft 13, a motor The rotating shaft 13 is rotatably held by a bearing provided in the housing. Inside the motor housing of the motor 10, an encoder 20, a motor control unit 30, and a motor drive circuit 40 provided on one end side of the rotary shaft 13 are disposed.
- Reference numeral 42 denotes a main power source.
- the motor control unit 30 and the motor drive circuit 40 are, for example, a dedicated ASIC (Application Specific Integrated Circuit) in which a plurality of necessary functions are integrated into a single chip in the form of a logic circuit, or a general-purpose single-chip microcomputer. It is realized as a chip of an IC circuit using Alternatively, it is realized as a part of the function of the computer. Below, the specific structural example using a single chip microcomputer is demonstrated.
- a single-chip microcomputer has a CPU, a memory, an oscillation circuit, a timer, an I / O interface, and a communication function (such as a serial I / F) integrated in one LSI.
- the functions of the motor control unit 30 and the motor drive circuit 40 of the brushless DC motor are realized by executing a specific program held in the memory on the CPU.
- the other end of the rotating shaft 13 of the brushless DC motor 10 is provided with a pinion that constitutes a speed reducer. That is, the rotation of the rotating shaft 13 is decelerated by the reduction gear and is transmitted to the driven member 50 directly or via a clutch.
- the driven member 50 include an automobile door opener, a water pump, and a wiper. Needless to say, the use of the motor 10 is not limited to automobiles.
- An encoder 20 that outputs a signal associated with the rotation of the rotary shaft 13 is provided inside the motor housing.
- the encoder 20 has a flat magnet 21 fixed to one end surface of the rotary shaft 13 and a change in magnetic field resistance caused by switching between the N-pole and S-pole of the magnet provided in the motor housing opposite to the magnet 21. And a magnetic sensor for detecting and outputting as an analog signal.
- the magnet 21 is fixed to one end surface of the rotating shaft 13 via a fixing member 126 and a fixing pin 127.
- the magnetic sensor includes a first Hall element group 22 composed of three Hall elements (H 1 -H 3 ), a second Hall element group 23 composed of three Hall elements (H 4 -H 6 ), A hall element power supply 24 for applying a common voltage Vcc to each hall element, and amplifiers 25 and 26 corresponding to the hall elements (H 1 to H 6 ) are provided.
- the Hall ICs having the same specifications are used for each Hall element (H 1 -H 6 ) of the magnetic sensor (in this specification, the Hall IC is simply referred to as “Hall element” unless it is necessary to distinguish between them). ).
- the first Hall element group (H 1 -H 3 ) 22 of the magnetic sensor is arranged on a single circumference centered on the rotation center of the rotary shaft 13 at equal intervals, that is, at 120 ° (mechanical angle) intervals. Has been placed.
- the second Hall element group (H 4 -H 6 ) 23 has a phase in the middle of the first Hall element group, that is, 60 degrees (mechanical angle) each on the same circumference as the first Hall element group. It is arranged at a position shifted. If the first and second Hall element groups are arranged on concentric circles having different radii, the voltage waveforms of the output signals detected by the first and second Hall element groups are different even at the same rotation angle. The outputs of the first and second Hall element groups cannot be easily compared, which is not practical.
- the motor control unit 30 and the motor drive circuit 40 include first and second absolute rotation information generation units 310 and 320, a memory 330, a motor 330, and the analog outputs 28 and 29 of the first and second Hall element groups, respectively.
- a control unit 340, a motor abnormality determination processing unit 350, and a communication control unit 360 are provided.
- the memory 330 includes a ROM, a RAM, and at least one rewritable (overwrite) non-volatile memory, and is connected to the CPU via a bus.
- Reference numeral 500 denotes a host control device such as an ECU (Electric Control Unit), a portable terminal, or a server connected via a network.
- the motor 10 In the motor control unit 340 of the motor control unit 30, the motor 10 according to the external command from the control device 500, the rotation information from the encoder 20, the current value of the motor main body 100, the information from the driven device 50, and the like. Drive signal is generated.
- the controlled electric power is supplied from the power supply terminal 48 to each of the three-phase (U-phase, V-phase, W-phase) stator coils of the motor 10 via the motor drive circuit 40.
- the ROM stores programs and constants that are executed when the power is turned on or reset.
- the RAM retains program variables, various external command values, control target values, absolute rotation information data to be described later, and the like.
- an EEPROM an FRAM (registered trademark) (Ferroelectric Random Access Memory), or the like may be employed as a non-volatile memory that can be rewritten (overwritten).
- a memory is simply referred to as an EEPROM.
- each analog signal input from the encoder 20 is converted into a digital signal, and an incremental signal (A, B) is generated. Further, based on the A-phase and B-phase signals, absolute rotation information of the Z-phase signal, U, V, and W-phase signals is generated, and the absolute rotation information is sequentially stored in a nonvolatile memory (such as an EEPROM) of the memory 330. Recorded / updated. That is, the first and second absolute rotation information obtained and generated under the same conditions except that only the rotation phase is different by 60 degrees are recorded and updated in the nonvolatile memory. In this embodiment, the first absolute rotation information is used as main rotation information for motor control, and the second absolute rotation information is used as backup information.
- the motor control unit 30 rotates the brushless DC motor that drives the driven member 50 based on command values from the outside stored in the memory 330 and various signals from the encoder 20, and consequently the driven member 50. Rotation position is calculated, and inverter drive signal information that supplies current to the U-phase, V-phase, and W-phase coils of the brushless DC motor is generated so that the driven member 50 operates at a predetermined target position. To do. Information on an inverter drive signal for DC motor drive based on these signals is output from the motor control unit 30 of the brushless DC motor to the motor drive circuit 40 via a serial communication line.
- a backup power source may be attached to the encoder 20, the control unit 30, and the memory (EEPROM) 330.
- the backup power source include a button battery and a lithium battery.
- This backup power supply is normally charged using the main power supply 42 as a power supply in a state where the key switch of the automobile is on. When the battery power is lost, it functions as a power source for the encoder, the motor control unit, and the EEPROM. Thereby, even if the battery power supply is lost due to an unexpected situation, the absolute position signal accompanying the driving of the driven member at the time of abnormal stop is recorded in the EEPROM.
- FIG. 2A is a longitudinal sectional view of the brushless DC motor based on the first embodiment
- FIG. 2B is a sectional view taken along line BB of FIG. 2A
- 2C is a cross-sectional view taken along the line CC of FIG. 2A.
- a three-phase stator coil 11 is fixed inside a cup-shaped motor housing constituting the motor body 100.
- the stator coil 11 includes nine field iron cores 112 arranged at equal intervals in the circumferential direction, and a field coil 111 wound through an insulating member 113 in a slot around each field iron core. .
- the field coil 111 wound around each field iron core 112 is a U-phase, V-phase, or W-phase, that is, a U-phase field coil (11U1), depending on the phase of the voltage applied from the motor drive circuit 40.
- U-phase field coils 11V1 to 11V3
- W-phase field coils 11W1 to 11W3
- the rotor 12 having an 8-pole permanent magnet is formed integrally with the rotary shaft 13, and these are provided in the first end cover 18 constituting a part of the motor housing of the motor 10 and the motor housing.
- a pair of bearings 16 and 17 are rotatably held.
- the rotor 12 is an 8-pole rotor having a rotor yoke 121 fixed to the rotary shaft 13 and eight permanent magnets 122 fixed to the outer periphery thereof.
- the outer peripheral surface of the rotor 12 faces the teeth of the stator core 11 via a gap.
- the specific configuration of the brushless DC motor 10 such as the number of slots, the number of magnet poles, the motor housing, and the cover is not limited to the embodiment.
- the encoder 20 and the motor control unit 30 are provided on a common substrate 27.
- the substrate 27 is made of a non-magnetic and electrically insulating resin plate or the like, and each Hall element (H 1 -H 6 ) is opposed to the magnet 21 by a plurality of, for example, three columns 125, and Each Hall element and each rotation center of the magnet 21 and the axis of the rotary shaft 13 are in a relationship that coincides with each other, and is fixed to the side surface of the motor housing and covered with a second end cover 19 made of a nonmagnetic material.
- the fixing member 126 is a cup-shaped member made of a non-magnetic material, such as a resin, and the magnet 21 is integrally molded at one end thereof, for example.
- the fixing member 126 is rotatable in the circumferential direction with respect to the rotating shaft 13 in a state where the rotating shaft 13 is inserted into the cup-shaped hollow portion, and the fixing member 126 is rotated by a fixing pin 127 or an adhesive. It is fixed with respect to the shaft 13.
- the relationship between the diameter of the rotating shaft 13, the diameter of the magnet, and the diameter of the circle in which each Hall element is arranged may be set as appropriate so that the same size or either side is slightly larger.
- the diameter of the circle on which each Hall element is arranged is 12 mm with respect to the diameter of the rotating shaft 13 being 10 mm.
- the magnet origin position (T 0 ) is defined as the position of one end of the flat magnet 21 on the boundary line between the N-pole region and the S-pole region. Also, a specific position on the rotation axis on the rotation axis corresponding to a position on the rotation axis synchronized with zero of the drive signal of the brushless DC motor, for example, a rising point of the A-phase pulse synchronized with zero of the drive signal. Is defined as the absolute origin position (Z 0 ).
- the magnet origin position (T 0 ) in FIG. 2C indicates a temporary origin position. This position should be the same as the absolute origin position (Z 0 ) on the rotation axis.
- the brushless DC motor is initially set so that the temporary origin position (T 0 ) of the magnet matches the absolute origin position Z 0. Is fixed to the rotation axis.
- T 0 temporary origin position
- the stator and rotor of the motor are assembled, an absolute origin position Z 0 on the rotation shaft with respect to the motor drive signal is obtained.
- the magnet 21 is temporarily fixed to the rotating shaft, and the brushless DC motor is driven to thereby generate a specific Hall element.
- This initial setting work is processed using, for example, an arm of a work robot with a camera function or by the worker himself. A specific method of this initial setting will be described in detail later.
- FIG. 3 is a diagram illustrating a configuration example of a drive circuit of the brushless DC motor in the first embodiment.
- each of the field coils 11U to 11W includes U1, U2, and U3 coils in series, V1, V2, and V3 coils in series, and W1, W2, and W3 coils in series. Connected. One end of each of these three coil groups is connected at a neutral point.
- the motor drive circuit 40 includes an inverter 400 including six switching elements FET1 to FET6 composed of FET transistors, an inverter drive control unit 410 that applies a voltage, that is, an inverter drive signal, between the gate and source of each of the switching elements FET1 to FET6, and current control.
- One end of each of the switching elements FET1 to FET6 is connected to one of the U-phase, V-phase, and W-phase coils 11U to 11W of the main body 100 of the brushless DC motor, and the other end is a direct current that is a main power source via a switch. Connected to a power source 42.
- the motor control unit 30 includes an operation command, a control signal generated based on the normal operation mode motor control signal (iu, iv, iw), and first and second absolute rotation information. Based on the above, the operation of the main body 100 of the brushless DC motor, for example, sinusoidal driving is continued. Thereby, the driven member 50 performs an operation based on a predetermined operation pattern within a predetermined operation range.
- the motor control unit 30 is mounted on a single substrate 27 together with the motor drive circuit 40.
- the substrate 27 is fixed to the inner surface of the motor housing and the second end cover 19 and at a position close to the encoder 20.
- the substrate 27 may be installed outside the brushless DC motor depending on the environment in which the brushless DC motor is installed.
- FIG. 4A shows a configuration example of the first absolute rotation information generation unit 310 and the second absolute rotation information generation unit 320.
- the first absolute rotation information generation unit 310 includes a first Hall element output processing unit 311, a sensor abnormality output unit 312, a first absolute rotation information conversion / recording unit 313, an origin position setting unit 314, a phase synchronization processing unit 315, and a Z phase.
- a signal and width signal generation unit 316 and a memory control unit 317 are provided.
- the second absolute rotation information generation unit 320 includes a second Hall element output processing unit 321, a sensor abnormality output unit 322, a first absolute rotation information conversion / recording unit 323, an origin position setting unit 324, and a phase synchronization processing unit 325.
- a Z-phase signal / width signal generation unit 326 and a memory control unit 327 are provided.
- the phase synchronization processing units 315 and 325 determine whether or not there is a phase shift between the first and second absolute rotation information.
- the motor control unit 340 and the motor abnormality determination processing unit 350 include a motor control signal generation unit 341, a drive signal generation unit 342, a self-initialization processing unit 343, a servo control unit 344, and a sensor / motor abnormality process.
- the motor control signal generation unit 341 generates a motor control signal based on a command from the motor control unit 30, drives the motor drive circuit 40 based on the signal generated by the drive signal generation unit 342, and is supplied to each stator coil. To control the phase of the current to rotate the rotor.
- the self-initialization processing unit 343 performs a self-initialization process of the control unit 30 when the motor is started, generates an initialization drive signal, outputs it to the motor drive circuit, drives the motor, and performs absolute rotation information necessary for initial setting. Processing such as generation and recording.
- the servo control unit 344 performs servo control of the brushless DC motor 10 based on a preset operation command value, an operation condition instructed from the outside, first and second absolute rotation information of the encoder 20, and the like. Further, the motor control unit 30 controls the maximum power and current supplied to the inverter drive control unit 410 via the current control unit 440 based on the current detected by the current detection / limitation unit 450.
- Reference numeral 460 denotes a current phase detector, which detects the back electromotive force (V BU , V BV , V BW ) of the coils of each phase of the brushless DC motor 10 at the initial setting, as will be described in detail later. 30. Further, the sensor / motor abnormality processing unit 345 executes processing when the sensor or motor is abnormal based on the first and second absolute rotation information from the encoder 20.
- FIG. 5 shows a configuration example of the first Hall element output processing unit 311 in the first absolute rotation information generation unit 310.
- the processing circuit unit 311 includes an AD converter 3111, an axis deviation correction processing unit 3112, a sensor abnormality determination unit 3113, an amplitude / angle conversion processing unit 3114, an average angle value (h 1 -avg.) Calculation unit 3115, and an average angle value.
- the output of the temperature sensor 318 is also input to the first hall element output processing unit 311 as necessary.
- the processing circuit unit 311 is realized by, for example, executing a specific program on a microcomputer with a memory, and sequentially, based on the analog input of the first Hall element group, the average angle value ( h 1- avg.) and the like.
- the second Hall element output processing unit 321 also has a similar configuration and has a function of calculating an average angle value (h 2 -avg.).
- the initial setting is to start a program related to the initial setting of the motor control unit 30, that is, the self-initialization processing unit 343, and set necessary parameters from the external terminal device 700. Is started (S601).
- the magnet 21 is temporarily fixed to the rotor (rotating shaft 13) of the motor at an arbitrary position (magnet origin position (T 0 )) (S603), and a pair of Hall element groups 22, 23 And the processing circuit (absolute rotation information generating units 310 and 320) are fixed to the side surface of the motor housing (S604), and the second end cover 19 is not yet fixed to the right side surface of the motor housing.
- the motor control unit 30 generates an arbitrary (predetermined) initialization drive signal for initial setting in response to the start of a program related to the initial setting (S602), and generates a three-phase stator coil (stator winding) of the motor.
- Drive power is supplied to start the motor (S605).
- the rotor 12 and the magnet 21 are rotated at a predetermined rotational speed in both forward and reverse directions (S606), and the encoder 20 (Hall element group) and the processing circuit (first and second absolute rotation information generating units) 1.
- a pulse signal based on the average angle values (h 1 -avg.) And (h 2 -avg.) Of the second Hall element group is generated (S607).
- a signal (T 0 ) of the magnet origin position is also generated and output.
- the motor control unit 30 generates an incremental A-phase / B-phase signal based on the average output values of the first and second hole groups, and assigns an EEPROM address to each A-phase and B-phase signal data. Then, a temporary absolute signal is generated (S608).
- FIG. 7 shows a concept of processing the analog signals of the hall elements output from the encoder 20 by the first and second absolute rotation information generation units 310 and 320 of the motor control unit 30.
- the Hall element group (H 1 -H 6 ) is provided such that the characteristic in which the electric resistance value varies with the direction of the acting magnetic field. For this reason, when the magnet 21 rotates positively (clockwise) by an angle ⁇ and the direction of the magnetic field acting on each Hall element rotates, the electrical resistance value of each Hall element, in other words, the output signal of each Hall element The voltage of fluctuates. That is, as shown in FIG. 7A, for each rotation 360 ° (mechanical angle) of the rotating shaft 13, an analog signal of a SIN wave for one cycle from each Hall element (H 1 -H 6 ). Is output.
- Each analog signal of the Hall element group passes through the corresponding analog input terminal of the microcomputer constituting the motor control unit 30, the multiplexer, and the sample hold circuit, and then each A of the first and second absolute rotation information generation units 310 and 320 / D converter 3111 is input, where each is converted into a digital signal.
- a digital signal obtained from each Hall element may include an error (mainly an axis deviation error) due to production errors, installation errors, temperature effects, and the like of each sensor.
- the axis deviation correction processing unit 3112 extracts the rotation center of each Hall element based on the data for one rotation of the rotating shaft 13, detects the presence or absence of signal distortion with respect to the rotation angle ⁇ , and if there is distortion, these The correction process is performed.
- the number of pulses of the A phase / B phase signal output for each rotation of the motor 10 depends on the accuracy of the Hall element, the resolution required for control, and the like. Any value can be set. For example, 500 to 1000 pulses are set for each rotation.
- the sensor abnormality determination unit 3113 if any one of the output pulses of each Hall element H 1 -H 3 per rotation is outside the predetermined threshold range with respect to the predetermined value, the Hall element is abnormal.
- the sensor abnormality output unit 312 outputs a sensor abnormality signal. For example, when the predetermined value for each rotation is set to 720 pulses, the threshold value is set to 2 pulses, and when this range is exceeded, it is determined that the Hall element is abnormal.
- the digital signal of the normal Hall element is then converted by the amplitude / angle conversion processing unit 3114 based on, for example, the following relationship, the amplitude A included in the output analog signal of each Hall element to the rotation angle ⁇ .
- A K ⁇ sin ⁇
- K is a constant. Therefore, if the arc sine (asin ⁇ ) value of A / K is taken, the rotation angle ⁇ can be obtained. In the range of 180 ° to 360 °, the output signal has a negative value.
- the average angle value calculation unit 3115 calculates the average value (h 1 -avg.) Of the outputs of the three Hall elements constituting the first Hall element group (H 1 -H 3 ) for each rotation of the rotation shaft. calculate. Note that the phase of the rotation angle at each Hall element (H 1 -H 3 ) installation position has a characteristic that it is hardly affected by temperature or the like. Therefore, in the present invention, an average value (h 1 -avg.) Is calculated based on the installation position of at least one of the following, and hereinafter the Hall element H 1 .
- the amplitude data of the output signal at the installation position of the intermediate Hall elements (H 2 , H 3 ) is also weighted and divided into multiple parts by interpolation processing of electrical angles.
- each rotation of the rotating shaft is converted into, for example, 720 pulses of A-phase and B-phase digital signals, respectively.
- the data of ⁇ a shown in (b) of FIG. 7 is obtained corresponding to the outputs of the three points of the first Hall element group (H 1 -H 3 ) of (a) of FIG. That is, as shown in FIG.
- FIG. 7D is an example of a first A-phase / B-phase signal based on the average value (h 1 -avg.) Of the outputs of the first hall element group (H 1 -H 3 ).
- A-phase and B-phase signals are assigned EEPROM addresses in the order of input, and become the basis of the first absolute rotation information.
- a magnet origin position (T 0 ) signal is generated once for each rotation of the rotating shaft 13 at an angle at which (h 1 -avg.) Becomes zero. This signal can also be used as a signal for detecting the rotational speed of the rotary shaft 13.
- FIG. 7C shows an example of an average value (h 2 -avg.) Of detection angle values based on the output of the second Hall element group
- FIG. 7E shows the detection of the second Hall element group. It is an example of a second A-phase / B-phase signal based on an average value (h 2- avg.) Of angle values.
- These A-phase and B-phase signals are assigned EEPROM addresses in the order of input, and become the basis of the second absolute rotation information.
- Positioning information Sn, Ssn (see FIG. 10) is generated every rotation angle (0 degree).
- the first and second A-phase / B-phase signals, positioning information Sn, Ssn, and sensor abnormality signal are held in the buffer memory 3119, and further, the nonvolatile memory ( The data is recorded / updated sequentially in an EEPROM or the like.
- the origin position setting unit 314 detects the back electromotive force (V BU , V BV , V BW ) of each phase accompanying the supply of driving power to the stator coil 111 of the motor.
- step S609 information on the phase Pz of the integrated value peak of the back electromotive force is acquired.
- the output signals of absolute rotation information A and B are used to adjust the motor to positive and negative rotational speeds in both forward and reverse directions according to the number of poles of the rotor 12.
- phase information is generated for each of the U-phase, V-phase, and W-phase signals that are required to make one rotation each and rise at intervals of 120 ° in electrical angle.
- a table of phase information of each signal of the U phase, the V phase, and the W phase is generated and recorded in the memory so that the rotor 12 rotates once every 45 ° of mechanical angle.
- the rising edge of the U-phase and V-phase signals is synchronized with the rising phase of the A-phase signal.
- phase information indicating the rising phase of the W-phase signal and the falling phase of the U-phase, V-phase, and W-phase signals is also recorded in the table. This point will be described later with reference to FIGS.
- the magnetic origin position (T 0 ), the output signals of A and B, and the rising phase Sn of each phase signal of the U phase, V phase, and W phase are synchronized, and provisional absolute rotation information (T 0 reference) is generated and recorded in the memory (S611).
- provisional absolute rotation information (T 0 reference) is generated and recorded in the memory (S611).
- the rising phase Sn of each of the U-phase, V-phase, and W-phase signals is extracted based on the phase of the integral value peak Pz obtained previously (S612). Further, U-phase, V-phase, with respect to the signal for each coil of the W-phase, to determine the width of the Z-phase T 0 reference.
- the Z-phase signal and width signal generation unit 316 generates a temporary absolute rotation information table to which the width signal of each phase is added (S613).
- the excitation current to the U-phase coil increases from the rising position of the first A-phase signal corresponding to the magnet origin position (T 0 ), in other words, from the rising position of the U-phase signal. Therefore, in the example of FIG.
- the integral value of the rotation angle ⁇ 100 ° (electrical angle), which is one in every rotation of the rotating shaft 13, for example, the exciting current to the U-phase coil is increasing.
- the peak position is recorded in the EEPROM as one piece of “positioning information (Sn)” for obtaining the absolute origin position of the magnet of the encoder.
- the origin position setting unit 314 obtains the absolute origin position (Z 0 ) of the rotating shaft with respect to the drive signal based on the relationship between the encoder output, the integral value peak, and the rotation angle information of the rotating shaft (S614). ). In this way, the data of the “absolute origin position (Z 0 ) on the rotation axis” based on the information on the integrated values of the A-phase, B-phase signal, and U-phase back electromotive force corresponding to the initial setting drive signal. Is obtained.
- FIG. 8 shows the A-phase and B-phase signals based on the magnet origin position (T 0 ) generated in the absolute rotation information generation unit, and the Z-phase, U-phase, and V-phase generated based on these signals. The relationship of each signal of a phase and a W phase is shown.
- the motor control unit 30 sends a command “fix the rotor, remove the temporary fixing of the magnet, and rotate the magnet with respect to the rotating shaft” to the work robot or worker (S616).
- a command “fix the rotor, remove the temporary fixing of the magnet, and rotate the magnet with respect to the rotating shaft” to the work robot or worker (S616).
- an output as shown in FIG. 7A that is, information on the magnet origin position (T 0 ) is obtained from the encoder 20 (S617).
- Information on the magnet origin position (T 0 ) of the magnet 21 is transmitted to the external terminal device 700 via the motor control unit 30 (S618).
- the motor control unit 30 further sends a command to “unlock the rotor” to the work robot or the like (S622).
- the position data of all of the signal obtained from the encoder is changed to an absolute origin position Z 0 reference, Z phase signal, is related to the "width of the Z phase", the address of the EEPROM is applied. In this way, it is converted into absolute rotation information representing the absolute origin position of the rotating shaft 13. That is, provisional absolute rotation information ((T 0 ) reference) of each phase signal is generated as a table of absolute rotation information corrected to the absolute origin position Z 0 reference (S623) and recorded in the EEPROM.
- the motor control unit 30 starts an initial setting program immediately after the power is turned on. First, immediately after the power is turned on, it is checked whether or not the initial setting has been completed. If not, the process proceeds to the initial setting processing mode.
- FIG. 9 shows details of the absolute rotation information generation process during the initial setting process of the motor control unit 30.
- the initial setting process first, the magnet 21 held by the fixing member 126 is temporarily fixed to the rotating shaft 13 by the fixing pin 127 at the temporary position ((T 0 ) reference) shown in FIG. 2C.
- the EEPROM data is initialized (S910), and the self-initialization processing unit 343 generates an initial setting drive signal for initial setting, for example, an inverter driving PWM signal ( ⁇ N rotation).
- the initial setting drive signals (iu, iv, iw) are sufficient to drive the brushless DC motor by one to several rotations in the forward and reverse directions with zero rotation therebetween (see FIG. 12).
- the initial setting drive signal is output to the motor control signal generator 342, and the main body 100 of the brushless DC motor is driven by the inverter drive signal (PWM signal) generated by the servo controller 344 (S911).
- the brushless DC motor is driven to supply power to the U-phase, V-phase, and W-phase coils in accordance with the initial setting drive signal while the brushless DC motor is in the open control state.
- the average output values (h 1 -avg.) And (h 2 -avg.) Of the first and second hole groups are acquired (S912).
- FIG. 10 shows average values (h 1 -avg.) And (h 2 -avg.) After the amplitude / angle conversion processing of the outputs of the first and second Hall element groups during the initial setting process, and positioning information ( (Sn, Ssn). Positioning information is generated at positions where the average value (h 1 -avg.) And (h 2 -avg.) Corresponding to 0 degrees of the A phase signal at the time of forward rotation command are zero (rotation angle 0 degree).
- Z ⁇ and Z ⁇ ′ indicate phases corresponding to the absolute origin position (Z 0 ) on the rotation axis, as will be described later.
- the absolute position of the magnet with respect to the rotation axis is obtained, and the process proceeds to a series of processes by the origin position setting unit 314 so that absolute signal data based on the absolute position information can be generated.
- the back electromotive force of each phase accompanying the supply of the drive power to the stator coil is detected, and the integral value peak Pz of the back electromotive force is detected.
- FIG. 11 is a diagram showing the relationship between the magnetic poles of each field coil of the stator and the current and the relationship between the back electromotive force of each field coil in a DC motor having a rotor having an 8-pole permanent magnet.
- the rotor 12 rotates by rotating the phase of the current supplied to the field coils 11U, 11V, 11W of the stator.
- Back electromotive forces Vbu, Vbv, and Vbw are generated in each field coil in accordance with the magnitude and direction of the current supplied to each field coil.
- the origin position setting unit 314 extracts the rising phase of each phase signal, performs an integration calculation of the back electromotive force of each phase, and detects a peak position Pz where the integration value exceeds a predetermined threshold value. Then, the rising position (Sn, Ssn) of each drive signal in the phase data of each drive signal of the U phase, V phase, and W phase is extracted (S918). For example, when attention is paid to the integral value peak of the U-phase counter electromotive force, six integral value peaks are obtained per one rotation (360 °). Similarly, for the V-phase field coils (11V1 to 11V3) and the W-phase field coils (11W1 to 11W3), six integral value peaks are obtained per rotation.
- the Z-phase signal and width signal generation unit 316 next sets the signal width of each phase coil (S919). For example, in synchronization with the rise of the A-phase signal, a signal of “Z width (1)” having a width of 1 ⁇ 2 period of the A-phase signal is determined. Further, in synchronization with the rise of the A-phase signal, a signal of “Z width (2)” having a width of one period of the A-phase signal is determined. Similarly, in synchronization with the rise of the B phase signal, a signal of “Z width (3)” having a width of 1 ⁇ 2 period of the B phase signal is determined. Further, in synchronization with the rise of the B phase signal, a signal of “Z width (4)” having a width of one period of the B phase signal is determined. The data of the width of each Z phase is used for generating a PWM signal.
- each A-phase / B-phase signal of the U-phase, V-phase, and W-phase signals from which the Z-phase signal was obtained is then calculated for each rotation (every 360 degrees) of the rotating shaft 13. It is converted into a cumulative added value, and the address of the EEPROM is given to the combination of this and the Z-phase signal, and it becomes (T 0 ) standard provisional absolute rotation information data.
- the origin position setting unit 314 based on the relationship between the average output values of the first and second hole groups, the integrated value peak, and the information on the rotation angle of the rotation axis, the absolute origin of the rotation axis with respect to the drive signal The position (Z 0 ) is obtained (S920).
- FIG. 12 is a time chart for explaining processing for obtaining the absolute origin position (Z 0 ) of the rotation axis with respect to the drive signal.
- the encoder 20 and the first and second absolute rotation information generators correspond to the command values (U, V, and W phase drive signals).
- a phase and B phase signals are obtained.
- the origin position setting unit 314 obtains a plurality of corresponding peak positions, that is, a plurality of positioning information.
- Positioning information (Sn, Ssn) corresponding to the absolute origin position (Z 0 ) on the rotating shaft should be output once for one rotation of the rotating shaft 13. Further, this positioning information is defined as a position corresponding to the rising point corresponding to 0 degrees of the A-phase signal in a section where the excitation current to any one of the U, V, and W coils is in the increasing direction. . In this case, it is necessary that the rotation axis passes through this absolute origin position (Z 0 ) while the brushless DC motor is rotating in the forward direction. Therefore, in the origin position setting unit 314, as shown in FIG. 12, the brushless DC motor is started, and the brushless DC motor is rotated forward or in a range including zero rotation between the initial setting drive signal (inverter drive signal). Reverse rotation.
- the ON duty of the PWM signal of the U-phase coil of the inverter drive signal is synchronized with zero, and it is determined that the phase Z ⁇ of the positioning information (S4) is synchronized with the absolute origin position (Z 0 ) on the rotation axis. .
- positioning information synchronized with the absolute origin position (Z 0 ) on the rotation axis may be output based on the excitation current to the V-phase or W-phase coil.
- the structure of the field coil 111 and the field iron core 112, and the switching position of the magnetic pole in the field iron core are mechanically obtained, and the magnetic pole is placed on the motor stator May be displayed as a mark, and the absolute origin position (Z 0 ) on the rotation axis may be obtained using this mark.
- the first absolute value table based on the magnet origin position (T 0 ) is a table of integrated values of high resolution A phase, B phase signal and U phase back electromotive force corresponding to the initial setting drive signal.
- high-accuracy “absolute origin position (Z 0 ) on rotation axis” data and phase information data of each signal of U phase, V phase, and W phase, ie, absolute origin position It is converted into an absolute value table based on Z 0 ). The same processing is performed for the second absolute value table.
- a request for magnet positioning is sent from the motor control unit 30 to the external terminal device 700, and in response to this, the motor control unit 30 proceeds to a magnet positioning process.
- the magnet 21 is relatively rotated on the rotating shaft 13 with the rotating shaft 13 fixed, the average output value of the first hole group with respect to the rotating angle is as shown by a sine waveform in FIG. Changes, and a magnet origin position (T 0 ) signal is output. Therefore, the magnet 21 is rotated with respect to the rotating shaft 13, and the average output value (magnet origin position (T 0 ) signal) of the first hole group matches the absolute origin position (Z 0 ) obtained previously. The magnet 21 is fixed to the rotating shaft 13 at this position.
- the magnet 21 is fixed at the absolute origin position (Z 0 ) on the rotating shaft 13. That is, the magnet 21 is fixed at a position where the origin position (T 0 ) of the magnet is synchronized with the absolute origin position (Z 0 ) of the rotating shaft 13.
- the fixing member 126 is fixed to the rotating shaft 13 with a fixing pin 127 or an adhesive. From these pieces of information, the relationship between the drive signal and the angle of the magnet on the rotating shaft is obtained, and the magnet is rotated relative to the rotating shaft. That is, by correcting the phases of the rising position Sn absolute origin position Z 0, the data of the tentative absolute rotation information, converts the absolute origin position data of the absolute rotation information as a reference (S921). As a result, the drive signal and the output of the encoder 20 can be completely synchronized.
- FIG. 13 is a flowchart showing details of the first absolute rotation information generation process in the normal operation mode after the initial setting process in the first embodiment.
- the brushless DC motor control unit 30 includes a motor control signal generation unit 341, a drive signal generation unit 342, a servo control unit 344, and the like that operate during external command and initial setting processing (or
- the brushless DC motor is caused to function as a servo motor on the basis of information in the EEPROM 333 (overwritten when the previous operation ends normally) or information from the encoder 20.
- the following processing is processing when all the sensors in the first and second Hall element groups are determined to be normal in S913 in FIG.
- the drive signal generation unit 342 generates U-phase, V-phase, and W-phase drive signals (S1301), and the initial setting process is performed from the memory (EEPROM, etc.) 333 (or the previous operation ends normally).
- the number of U-phase, V-phase, and W-phase pulses corresponding to the drive signal (overwritten on) is acquired (S1302), and the Z-phase signal and Z-phase signal (Z1, Z2,-,-, Zn) are obtained.
- Phase data is acquired (S1303).
- the control unit 30 acquires Z signals based on the average values (h 1 -avg., H 2 -avg.) Of the detected angle values of the first and second Hall element groups.
- the first and second signals including A, B, Z, U, V, and W signals for each rotation of the rotation shaft of the motor according to the forward rotation and reverse rotation of the rotation shaft of the brushless DC motor.
- Absolute rotation information is incremented and decremented, and these pieces of information are sequentially recorded in the EEPROM via the RAM as information indicating the current position of the rotation axis of the brushless DC motor. This process is repeated until the end of operation (S1311).
- the control unit 30 rotates the rotation speed of the brushless DC motor based on the A-phase / B-phase signal from the first absolute rotation information generation unit 310. -Recognizes the rotation direction and absolute origin position, compares the recognized rotation speed and rotation direction, and absolute origin position with the command value, and drives the inverter for each of the U-phase, V-phase, and W-phase coils. A wave drive signal is generated. Further, the voltage is continuously changed by controlling the duty ratio of the PWM signal for the inverter as the motor drive circuit 40.
- the motor control unit 340 of the control unit 30 first obtains each target position and target speed as a command value from a memory 330 such as a RAM based on a preset operation pattern of the brushless DC servo motor. (S1401).
- a memory 330 such as a RAM based on a preset operation pattern of the brushless DC servo motor.
- a motor drive signal based on sine wave drive or PID control for example, a PWM control signal Is stored.
- the motor control unit 340 acquires multi-rotation / absolute origin position information based on the output of the first hall element group (S1402). Further, multi-rotation / absolute origin position information based on the output of the first Hall element group is also acquired (S1403). Next, the presence / absence of abnormality of the Hall elements of the first and second Hall element groups is checked (S1404). If any of the Hall elements is abnormal, the abnormality information is transmitted to the host ECU ( Along with S1405), when there is a normal Hall element group, backup control based on the output is performed (S1414).
- the motor control unit 340 rotates the rotation shaft 13 of the brushless DC motor based on the acquired multi-rotation / absolute origin position information based on the acquired output of the first Hall element group. The angle and thus the absolute position of the driven member 50 is recognized.
- the motor control unit 340 calculates a speed command value from the current position of the driven member 50 to the target position based on these pieces of information. Further, based on the speed command value and the like, an inverter drive signal for PID control of the rotation of the brushless DC motor is generated (S1406) and output to the motor drive circuit 40 (S1407).
- the motor control unit 340 updates the first and second multi-rotation / absolute rotation information based on the outputs of the first and second Hall element groups accompanying the rotation of the motor (S1408, 1409).
- the motor control unit 340 further calculates the presence / absence of a difference value of the multi-rotation / absolute rotation information based on the outputs of the first and second Hall element groups, and determines the “deviation” of the outputs of the first and second Hall element groups. The presence or absence is determined (S1410).
- the first and second multi-rotation / absolute rotation information recorded in the EEPROM is compared with information on the A phase based on, for example, the current address, that is, the latest address.
- the allowable value is 2 pulses, and when this range is exceeded, it is determined that the motor is abnormal.
- “displacement” is the second determination (S1411, S1412), it is determined that there is an abnormality in the motor, and abnormality information is transmitted to the ECU 500 (S1413). Note that even when there is an abnormality in the EEPROM itself, not in the encoder 20, it can be checked at this point. Then, when there is a normal Hall element group, backup control based on the output is performed (S1414).
- the first and second multi-rotation absolute signals are data having substantially the same value and the same absolute origin position (Z 0 ). Therefore, even if one set of Hall element group (or one set of absolute rotation information generation unit) breaks down, the output of the other Hall element group (or one set of absolute rotation information generation unit) smoothly shifts to backup control. it can. If there is no “deviation” in the deviation determination (S1410), a new inverter drive signal is generated (S1406), and the same processing is repeated thereafter, and the operation is terminated in the end determination (S1415).
- the brushless DC motor of the present embodiment is a servo motor that is controlled using the output of one encoder 20 that functions as a rotary encoder.
- multi-rotation / absolute rotation information consisting of data of substantially the same value is generated using the output signals of two sets of Hall element groups having the same characteristics, and the failure determination is inexpensive and highly reliable. Therefore, it is possible to provide a DC motor control device. Further, even when one set of hall element groups fails, backup control can be immediately performed by the output of the other hall element groups. Therefore, it is possible to provide an inexpensive and highly reliable DC motor control device that can generate position information with relatively high accuracy.
- FIG. 15 is a longitudinal sectional view of a brushless DC motor based on the second embodiment.
- the three-phase stator coil 11 is composed of nine field cores 112 arranged at equal intervals in the circumferential direction, and a field coil 111 wound through an insulating member 113 in a slot around each field core.
- the rotor 12 having an 8-pole permanent magnet is formed integrally with the rotary shaft 13 and is rotatably held by a pair of bearings 16 and 17.
- the rotor 12 is an 8-pole rotor having a rotor yoke 121 fixed to the rotating shaft 13 and eight permanent magnets 122 fixed to the outer periphery thereof (see FIG. 2B).
- each hall element (H 1 -H 6 ) of the encoder 20 is opposed to eight permanent magnets 122 by three support pillars 125, and the center of rotation of each hall element and the axis of the rotary shaft 13 are arranged. It is fixed to the side surface (second end cover) 19 of the cup-shaped motor housing in a matching relationship.
- substrate 27 is provided with the long hole for enabling the three support
- the motor control unit 30 is fixed inside the second end cover 19 together with the motor drive circuit 40.
- the motor control unit 30 and the motor drive circuit 40 may also be disposed on the substrate 27.
- the function of the motor control unit 30 is almost the same as that of the first embodiment except for the points described below.
- the position of the boundary line of the N pole and S pole of the pair of permanent magnets 122 which corresponds to the Z 0 in FIG. 12 And defined as a permanent magnet origin position (Z 0 ).
- a specific position in the circumferential direction is defined as the Hall element origin position (T 0 ).
- the origin positions (T 0 ) of the Hall element groups 22 and 23 in FIG. 15 are provisional origin positions, which should originally coincide with the permanent magnet origin position (Z 0 ).
- the magnet 21 is temporarily fixed to the rotation shaft.
- the rotation shaft 13 and the rotor 12 are integrated. Therefore, the position of each Hall element (H 1 -H 6 ) on the substrate 27 is set as a temporarily fixed position, the relative position of the rotor 12 with respect to the permanent magnet is corrected, and the origin positions of the Hall element groups 22 and 23 ( T 0) to coincide with the origin position of the permanent magnet (Z 0).
- each column 125 for rotating the substrate 27 held by the three columns 125 in the circumferential direction is provided. Corresponding long holes are provided in the substrate 27.
- the substrate 27 is fixed to each column 125 at an arbitrary position.
- the change in the magnetic field strength as shown in FIG. 7A accompanying the change in the origin position (T 0 ) of the Hall element groups 22 and 23 is represented by the first and second absolute rotation information generation units 310 and 320. Detect with.
- information on the absolute positional relationship of the substrate 27 (Hall element groups 22, 23) with respect to the rotation axis (permanent magnet 122) is acquired, and processing corresponding to Step 621 in FIG.
- the substrate 27 is formally fixed to each column 125.
- the subsequent processing is the same as in FIG.
- position information consisting of data of substantially the same value is generated using output signals of two sets of Hall element groups having the same characteristics with respect to the permanent magnet of the rotor, and is inexpensive and highly reliable. It is possible to provide a DC motor control device capable of determining a failure. Further, even when one set of hall element groups fails, backup control can be immediately performed by the output of the other hall element groups. Therefore, it is possible to provide an inexpensive and highly reliable DC motor control device that can generate position information with relatively high accuracy.
- FIG. 16 is a functional block diagram illustrating a configuration example of a brushless DC motor control device based on the third embodiment.
- the brushless DC motor 10 of the present embodiment includes an outer rotor 1000 and a stator 1200 that rotatably supports the rotor 1000.
- the rotor 1000 includes a rotating shaft 1300, a cup-shaped rotor cover 1100 having the rotating shaft 1300 fixed to the bottom surface, and a multi-pole magnet 1120 disposed along the inner peripheral surface of the cylindrical portion of the rotor cover 1100. It has.
- the stator 1200 includes a support member 1205 that rotatably supports the rotating shaft 1300 via a pair of bearings 16 and 17, and a cylinder of the support member 1205 via a radial gap inside the magnet 1120 of the rotor 1000.
- a stator core 1220 fixed to the shape part 1202 with screws or the like, and a stator coil 1210 wound around the stator core 1220 are provided.
- the end cover 26 is fixed to the support member 1205 from the outside.
- An encoder 20 is provided at one end of the rotating shaft 1300 and the end cover 26.
- the encoder 20 includes a flat plate-like magnet 21 fixed to one end surface of the rotating shaft 1300 and two sets of hall element groups arranged on the motor housing side facing the magnet 21 in the axial direction of the rotating shaft. It is out.
- the Hall element group includes a first Hall element group (H 1 -H 3 ) 22 composed of three Hall elements, a second Hall element group (H 4 -H 6 ) 23 composed of three Hall elements, A hall element power supply 24 for applying a common voltage Vcc to the hall elements and amplifiers 25 and 26 corresponding to the hall elements (H 1 to H 6 ) are provided.
- the function of the motor control unit 30 is almost the same as that of the first embodiment.
- position information composed of substantially the same value data is generated using the output signals of two sets of Hall element groups having the same characteristics, and is inexpensive and highly reliable. It is possible to provide a DC motor control device capable of determining a failure. Further, even when one set of hall element groups fails, backup control can be immediately performed by the output of the other hall element groups. Therefore, it is possible to provide an inexpensive and highly reliable outer rotor type DC motor control device that can generate position information with relatively high accuracy.
- the present invention can also be applied to a DC motor with a brush.
- the configuration of the magnet in the MR sensor unit in the DC motor described in Patent Document 1 is the same as that of the magnet in this embodiment, and the present invention is implemented in place of the pair of MR sensor and processing circuit section in Patent Document 1.
- the first and second Hall element groups 22 and 23 described in Example 1 and the first and second absolute rotation information generation units 310 and 320 are employed. That is, according to the fourth embodiment, in the brushed DC motor, the encoder includes a flat magnet fixed to one end surface of the rotating shaft, and three Hall elements provided in the motor housing facing the magnet.
- a first Hall element group consisting of (H 1 -H 3 ), a second Hall element group consisting of three Hall elements (H 4 -H 6 ), and a common voltage Vcc are applied to each Hall element.
- the power source and amplifiers 25 and 26 corresponding to the Hall elements (H 1 to H 6 ) are included.
- the output of the encoder is processed by the first and second absolute rotation information generation units 310 and 320.
- the absolute origin position Z 0 of the rotating shaft to associate to the position of the boundary line of the N pole area and the S pole area of the magnet can be set at an arbitrary position. Therefore, the motor control unit of the fourth embodiment does not require the fixing member 126 and the fixing pin 127 of the first embodiment.
- the motor control unit has average values (h 1 -avg.), (H 2 ) after the amplitude / angle conversion processing of the outputs of the first and second Hall element groups. -. and avg), obtains the relationship between the positioning information (Sn, Ssn), among these positioning information, oN duty of the drive signal is a position to be synchronized to zero, synchronized with the rising edge of the a-phase pulse
- the absolute origin position of the encoder That is, the motor control unit of the fourth embodiment has substantially the same configuration and function as those of the first embodiment except for the function related to the extraction of the absolute origin position of the rotating shaft.
- position information consisting of data of substantially the same value is generated using the output signals of two sets of Hall element groups having the same characteristics, and a low-cost and highly reliable failure It is possible to provide a control device for a DC motor that can be determined. Further, even when one set of hall element groups fails, backup control can be immediately performed by the output of the other hall element groups. Therefore, it is possible to provide an inexpensive and highly reliable DC motor controller with a brush that can generate position information with relatively high accuracy.
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Abstract
Description
特許文献2に記載の発明は、絶対角度位置検出装置として、回転軸の端面側に設けられた絶対位置エンコーダと、回転軸の半径方向外側に設けられたインクリメンタル形エンコーダとを備えており、全体として、構成が複雑である。
特許文献3に記載の発明では、4個のホール素子の出力値を演算し、それらの少なくとも1つに基づきトーションバーの捩じれ角を演算している。しかし、特許文献3には、ホール素子のセンサとしての信頼度の低さを補うことについての配慮は開示されていない。
前記エンコーダは、前記ロータの回転軸の一端に固定され、径方向に着磁された1組のN極領域とS極領域を有する平板状のマグネットと、該マグネットに対向する位置で前記モータのハウジング側に固定された、2組のホール素子群とを備えており、
前記2組のホール素子群は、前記回転軸の回転中心を中心とする単一の円周上に、3個のホール素子が等間隔で配置された第1のホール素子群と、前記第1のホール素子群と同じ円周上において、前記第1のホール素子群の中間に3個のホール素子が等間隔で配置された第2のホール素子群とを有しており、
前記制御ユニットは、前記マグネットのN極領域とS極領域の境界線上の位置を、マグネット原点位置とし、前記2組のホール素子群の出力に基づいて、前記回転軸の回転に伴うA相、B相の信号を生成して出力するとともに、前記マグネットの原点位置の情報を生成する機能と、前記ロータの極数に合わせて前記U相、V相、W相の各位相情報を生成する機能と、前記ブラシレスDCモータのステータの各界磁コイルの磁極と電流の関係と前記駆動信号の零に対応する前記A相若しくは前記B相の出力信号の立ち上がり位相との同期関係に基づき、前記駆動信号に対する前記回転軸の絶対原点位置を取得する機能と、前記A相、B相、及び、前記U相、V相、W相の各位相の情報を、前記回転軸の前記絶対原点位置を基準とするアブソリュート信号のデータに変換する機能とを備えており、前記マグネットは前記原点位置が、前記回転軸の前記絶対原点位置と同期する位置に固定されており、
前記エンコーダを前記U相、V相、及びW相のロータリーエンコーダとして、前記アブソリュート信号に基づき前記モータを駆動するように構成されている。
なお、書き換え(重ね書き)可能な不揮発性のメモリとして、EEPROMやFRAM(登録商標)(Ferroelectric Random Access Memory)などを採用すればよい。以下の説明では、このようなメモリを、単にEEPROMとして記載する。
本実施例では、第1のアブソリュート回転情報をモータ制御用のメインの回転情報として使用し、第2のアブソリュート回転情報はバックアップ情報として使用する。
ブラシレスDCモータ10は、モータ本体100を構成するカップ状のモータハウジングの内部に、3相のステータコイル11が固定されている。ステータコイル11は、周方向に等間隔に配置された9個の界磁鉄心112と、各界磁鉄心周りのスロット内に絶縁部材113を介して巻かれた界磁コイル111とで構成されている。各界磁鉄心112に巻回された界磁コイル111は、モータ駆動回路40から印加される電圧の位相によって、U相、V相、W相の各相、すなわち、U相の界磁コイル(11U1~11U3)、V相の界磁コイル(11V1~11V3)、及び、W相の界磁コイル(11W1~11W3)に分類される。
なお、ブラシレスDCモータ10のスロット数やマグネットの極数、モータハウジングやカバーなどの具体的構成は、実施例に限定されるものではない。
また、回転軸13の直径と、マグネットの直径、各ホール素子が配置される円の直径の関係は、同等のサイズ、あるいは、いずれかの側が若干大きくなるように、適宜設定すれば良い。一例を挙げると、回転軸13の直径が10mmに対して、各ホール素子の配置される円の直径は12mmである。
図2Cのマグネット原点位置(T0)は、仮の原点位置を示している。この位置は、本来、回転軸上の絶対原点位置(Z0)と一致すべきものである。
ステータコイル11において、各相の界磁コイル11U~11Wは、U1,U2,U3のコイルが直列に、V1,V2,V3のコイルが直列に、W1,W2,W3のコイルが直列に、各々結線されている。これらの3つのコイル群は、各々の一端が中性点で接続されている。
位相同期処理部315、325は、第1、第2のアブソリュート回転情報間の位相のずれの有無を判定する。
モータ制御信号生成部341において、モータ制御ユニット30からの指令に基づきモータ制御信号を生成し、駆動信号生成部342で生成された信号に基づきモータ駆動回路40を駆動して各ステータコイルに供給される電流の位相を制御し、ロータを回転させる。自己イニシャライズ処理部343は、モータの起動時に、制御ユニット30の自己イニシャライズ処理を行い、イニシャライズ駆動信号を生成してモータ駆動回路へ出力し、モータを駆動して、初期設定に必要なアブソリュート回転情報の生成・記録等の処理を行う。サーボ制御部344は、予め設定された運転指令値や外部から指示された運転条件とエンコーダ20の第1、第2アブソリュート回転情報等基づいて、ブラシレスDCモータ10のサーボ制御を実行する。また、モータ制御ユニット30は、電流検出/制限部450で検出された電流に基づき、電流制御部440を介して、インバータ駆動制御部410に供給される最大の電力や電流を制御する。460は電流位相検出部であり、後で詳細に述べるように、初期設定時にブラシレスDCモータ10の各相のコイルの逆起電力(VBU、VBV、VBW)を検出し、モータ制御ユニット30に伝送する。また、センサ・モータ異常時処理部345は、エンコーダ20からの第1、第2アブソリュート回転情報に基づいて、センサやモータの異常時における処理を実行する。
初期設定は、図6のタイムチャートに示したように、外部端末装置700から、モータ制御ユニット30の初期設定に関係したプログラム、すなわち自己イニシャライズ処理部343を起動し、必要なパラメータを設定することにより、開始される(S601)。
なお、この段階では、モータのロータ(回転軸13)に、マグネット21が任意の位置(マグネット原点位置(T0))で仮固定されており(S603)、1対のホール素子群22、23や処理回路(アブソリュート回転情報生成部310、320)が、モータハウジングの側面に固定され(S604)、かつ、第2のエンドカバー19はまだモータハウジングの右側面に固定されていない。
ホール素子群(H1-H6)は、作用する磁界の方向に対して電気抵抗値の変化する特性が異なるように設けられている。このため、マグネット21が角度Θだけ正回転(時計周り)して各ホール素子に作用する磁界の向きが回転すると、それに対応して各ホール素子の電気抵抗値、換言すると各ホール素子の出力信号の電圧が変動する。すなわち、図7の(a)に示したように、回転軸13の1回転360°(機械角)毎に、各々のホール素子(H1-H6)から1周期分のSIN波のアナログ信号が出力される。
各ホール素子から得られるデジタル信号は、各センサ等の制作誤差、設置誤差、温度の影響等により、誤差(主に軸ずれ誤差)を含んでいる可能性がある。軸ずれ補正処理部3112では、回転軸13の1回転分のデータに基づき、各ホール素子の回転中心を抽出し、回転角度Θに対する信号のひずみの有無を検知し、ひずみがある場合にはそれらの補正処理を行う。
センサ異常判定部3113では、1回転毎の各ホール素子H1-H3のいずれかの出力パルスが所定値に対して予め設定された閾値の範囲外である場合には、そのホール素子に異常有りと判定し、センサ異常出力部312からセンサ異常信号を出力する。例えば1回転毎の所定値が720パルスに設定されている場合、閾値を2パルスとし、この範囲を超えた場合には、そのホール素子に異常有りと判定する。
A=K×sinθ
但し、Kは定数
従って、A/Kのアークサイン(asinθ)値をとれば、回転角θが得られる。180°~360°の範囲では、出力信号が負の値となる。
例えば、図7の(a)の第1ホール素子群(H1-H3)の3点の出力に対応して、図7の(b)に示すθaのデータが得られる。すなわち、図7の(b)に示したように、同一円周上でかつ120度ずつ位相の異なる3点の第1ホール素子群(H1-H3)の出力を平均値化することで、より精度の高い角度のデータ(h1-avg.)を取得する。
この検出角度値の平均値(h1-avg.)を、エンコーダ20の第1ホール素子群の出力とする。
なお、ホール素子の数を4個以上とすることも考えられるが、構成が複雑化しコストアップするのに比して得られる精度向上の効果が少ないので、実用的ではない。
なお、パルスカウンタ3116にはアップダウンカウンタを採用し、パルスの累積加減算値に、回転軸13の正逆の回転方向の情報も付加したA相、B相信号を生成するのが望ましい。また、回転軸13の1回転毎に1回、(h1-avg.)が零になる角度において、マグネット原点位置(T0)信号を生成する。この信号は、回転軸13の回転数を検知する信号と兼用することもできる。
第1アブソリュート回転情報生成部による検出角度値の平均値(h1-avg.)と第2アブソリュート回転情報生成部による検出角度値の平均値(h2-avg.)との間には、位相差(機械角)θBの差がある。換言すると、マグネット21が逆回転する場合には、この位相差の関係は逆になる。
一方、初期設定駆動信号(iu,iv,iw)に合わせて、アブソリュート回転情報のA,Bの出力信号から、ロータ12の極数に合わせて、モータを正逆双方向に正負の回転数、例えば各々1回転させるのに必要な、電気角で120°の間隔で立ち上がるU相、V相、W相の各信号の位相情報を生成する。例えば、機械角45°毎に、ロータ12が1回転するように、U相、V相、W相の各信号の位相情報のテーブルを生成し、メモリに記録する。
なお、この段階では、このマグネット原点位置(T0)が、エンコーダの絶対原点位置(Z0)とどのような対応関係にあるかは明確ではない。
さらに、U相、V相、W相の各コイルに関する信号に対して、T0基準のZ相の幅を確定する。そして、Z相信号及び幅信号の生成部316で、各相の幅信号を付加した暫定アブソリュート回転情報のテーブルを生成する(S613)。
マグネット原点位置(T0)に対応する最初のA相信号の立ち上がり位置、換言するとU相信号の立ち上がり位置から、U相コイルへの励磁電流が増加する。そのため、図7の(b)の例では、回転軸13の1回転に1つ、例えば、U相コイルへの励磁電流が増加方向にある、回転角度Θ=100°(電気角)の積分値ピークの位置が、エンコーダのマグネットの絶対原点位置を求めるための1つの「位置決め情報(Sn)」とし、EEPROMに記録される。
このようにして、初期設定駆動信号に対応するA相、B相信号及びU相の逆起電力の積分値の情報を基にした、「回転軸上の絶対原点位置(Z0)」のデータが得られる。
本発明の第1の実施例におけるモータ制御ユニット30は、電源立ち上げ直後に、初期設定プログラムを起動する。まず、電源立ち上げ直後に、初期設定済か否かをチェックし、否の場合、初期設定処理モードに移行する。
初期設定処理では、まず、固定部材126に保持されたマグネット21を、図2Cに示した暫定位置((T0)基準)で回転軸13に対して固定ピン127により仮固定する。そして、EEPROMデータの初期化を行い(S910)、自己イニシャライズ処理部343で、初期設定のための初期設定駆動信号、例えばインバータ駆動用のPWM信号(±N回転)を生成する。初期設定駆動信号(iu,iv,iw)は、ブラシレスDCモータを、零回転を挟んで正、逆方向に各々1~数回転だけ駆動する信号で足りる(図12参照)。この初期設定駆動信号を、モータ制御信号生成部342へ出力し、サーボ制御部344において生成されたインバータ駆動信号(PWM信号)で、ブラシレスDCモータの本体100を駆動する(S911)。初期設定処理では、ブラシレスDCモータをオープン制御の状態で、初期設定駆動信号により、U相、V相、W相の各コイルへ電力を供給してブラシレスDCモータを駆動する。そして、第1、第2のホール群の平均出力値(h1-avg.)、(h2-avg.)を取得する(S912)。
そして、第1、第2のホール群の平均出力値に基づく、A相・B相の信号を生成する。また、第1、第2のホール素子群のセンサが正常か判定する(S913)。例えば、位相同期処理部315、325により、第1、第2のホール群の平均出力値に基づく、A相・B相の信号の位相が所定の関係(位相差=θB)にあるかを判定する。また、異常信号が出力されているセンサがある場合には、正常なホール素子群の出力でA相・B相の信号を生成する(S914)。第1、第2のホール素子群のセンサが共に異常の場合には、安全のための緊急の運転モードに移行する。ホール素子の異常は、上位のECUに通知するとともに、センサ・モータ異常時処理部345で所定の処理を実行する(S915)。
ステータの各界磁コイル11U,11V,11Wへ供給される電流の位相を回転させることにより、ロータ12が回転する。この各界磁コイルへ供給される電流の大きさとその方向に応じて、各界磁コイルに逆起電力Vbu、Vbv、Vbwが発生する。
例えば、U相の逆起電力の積分値ピークに着目すると、1回転(360°)当たり、6回の積分値ピークが得られる。同様に、V相の界磁コイル(11V1~11V3)、及び、W相の界磁コイル(11W1~11W3)に関しても、各々、1回転当たり、6回の積分値ピークが得られる。
例えば、A相信号の立ち上がりに同期し、A相信号の1/2周期の幅を有する「Zの幅(1)」の信号を確定する。さらに、A相信号の立ち上がりに同期し、A相信号の1周期の幅を有する「Zの幅(2)」の信号を確定する。同様にして、B相信号の立ち上がりに同期し、B相信号の1/2周期の幅を有する「Zの幅(3)」の信号を確定する。さらに、B相信号の立ち上がりに同期し、B相信号の1周期の幅を有する「Zの幅(4)」の信号を確定する。各Z相の幅のデータは、PWM信号の生成などに用いられる。
インバータ駆動信号を出力してブラシレスDCモータを正・逆双方向に駆動すると、エンコーダ20及び第1、第2アブソリュート回転情報生成部から、指令値(U,V,W相の駆動信号)に対応するA相、B相信号が得られる。また、前記した通り、位相検出部460からのデータに基づき、原点位置設定部314において、対応する複数のピーク位置、すなわち、複数の位置決め情報が得られる。
そこで、原点位置設定部314において、図12に示すように、ブラシレスDCモータを起動し、初期設定駆動信号(インバータ駆動信号)により、間に零回転を含む範囲で、ブラシレスDCモータを正回転もしくは逆回転させる。
なお、U相コイルに代えて、V相若しくはW相のコイルへの励磁電流を基に、回転軸上の絶対原点位置(Z0)に同期する位置決め情報を出力するようにしても良い。
第2のアブソリュート値のテーブルについても同様に処理される。
回転軸13を固定した状態で、回転軸13上でマグネット21を相対的に回転させると、回転角度に対して、第1ホール群の平均出力値が、図7にサイン波形で示されるように変化し、マグネット原点位置(T0)信号が出力される。そこで、マグネット21を回転軸13に対して回転させ、第1ホール群の平均出力値(マグネット原点位置(T0)信号)が、先に求めた絶対原点位置(Z0)と一致する位置を求め、この位置でマグネット21を回転軸13に固定する。このようにして、マグネット21は回転軸13上の絶対原点位置(Z0)に固定される。すなわち、マグネット21は、このマグネットの原点位置(T0)が、回転軸13の絶対原点位置(Z0)と同期する位置に固定される。
これらの情報から、駆動信号と回転軸上のマグネットの角度の関係が求まり、マグネットを回転軸に対して相対的に回転させる。すなわち、各相の立ち上がり位置Snを絶対原点位置Z0で補正して、暫定アブソリュート回転情報のデータを、絶対原点位置を基準とするアブソリュート回転情報のデータに変換する(S921)。これにより、駆動信号とエンコーダ20の出力とを完全に同期させることが可能になる。
これらの第1、第2のアブソリュート回転情報は、いずれも同じ絶対原点位置(Z0)を基準としている。従って、全ホール素子群(H1-H6)が正常に機能している場合、A相、B相のデジタル信号にEEPROMのアドレスが付与された後の第1、第2のアブソリュート値のテーブルのデータは、実質的に同じ値のデータである。
モータ制御ユニット30では、次に、Z0基準の第1、第2の多回転のアブソリュート回転情報(累積加算値)を、各々、EEPROM333に記録する(S923)。
ブラシレスDCモータの制御ユニット30は、正規の運転処理モードにおいては、モータ制御信号生成部341、駆動信号生成部342、サーボ制御部344等が動作し、外部指令、初期設定処理時の(又は、前回の運転が正常に終了した場合に上書きされた)EEPROM333の情報やエンコーダ20からの情報に基づき、ブラシレスDCモータを、サーボモータとして機能させる。なお、以下の処理は、図9のS913で、第1、第2のホール素子群の全てのセンサが正常と判定された場合の処理である。
すなわち、ブラシレスDCモータの回転軸の正回転、逆回転に応じて、モータの回転軸の1回転毎に、A、B、Z、U、V、Wの各信号を含む第1、第2のアブソリュート回転情報がインクリメント、デクリメントされ、これらの情報は、ブラシレスDCモータの回転軸の現在位置を表す情報として、逐次、RAMを経由してEEPROMに記録される。この処理を、運転終了(S1311)まで繰り返えす。
通常運転モードにおいて、制御ユニット30のモータ制御部340は、まず、RAM等のメモリ330から、予め設定されたブラシレスDCサーボモータの運転パターンに基づく、各目標の位置や目標速度を指令値として取得する(S1401)。メモリには、被駆動部材の各目標位置に対応して設定されたブラシレスDCサーボモータの運転パターンに対応する目標速度として、正弦波駆動やPID制御を前提としたモータ駆動信号、例えばPWM制御信号のデータが格納されている。
モータ制御部340は、さらに、第1、第2ホール素子群の出力に基づく多回転・アブソリュート回転情報の差分値の有無を算出し、第1、第2ホール素子群の出力の「ずれ」の有無を判定する(S1410)。
「ずれ」判定においては、EEPROMに記録されている第1、第2の多回転・アブソリュート回転情報に関して、例えば現在の、換言すると最新のアドレスに基づきA相の情報を比較する。A相の累積加算値の差分値が許容値を超えていれば「ずれ」有と判定する。例えば1回転720パルスの場合、許容値を2パルスとし、この範囲を超えた場合には、モータの異常と判定する。これらの結果に基づいて、「ずれ」有りが2回目の判定である場合(S1411、S1412)、モータに異常があると判定し、ECU500に、異常情報を送信する(S1413)。なお、エンコーダ20ではなく、EEPROM自体に異常がある場合にも、この時点でチェックできる。そして、正常なホール素子群がある場合にその出力に基づくバックアップ制御を行う(S1414)。
ずれ量の判定(S1410)で「ずれ」がなかった場合、新たなインバータ駆動信号を生成し(S1406)、以下、同様の処理を繰り返し、終了の判定(S1415)で運転を終了する。
本実施例によれば、同じ特性の2組のホール素子群の出力信号を利用して実質的に同じ値のデータからなる多回転・アブソリュート回転情報を生成し、安価で信頼性の高い故障判定が可能な、DCモータの制御装置を提供できる。また、1組のホール素子群が故障した場合も、他のホール素子群の出力で直ちにバックアップ制御できる。そのため、比較的高精度の位置情報を生成できる、安価で信頼性の高いDCモータの制御装置を提供することができる。
3相のステータコイル11は、周方向に等間隔に配置された9個の界磁鉄心112と、各界磁鉄心周りのスロット内に絶縁部材113を介して巻かれた界磁コイル111で構成されている。一方、8極の永久磁石を有するロータ12が、回転軸13と一体に形成され、1対の軸受16、17により、回転自在に保持されている。ロータ12は、回転軸13に固定されたロータヨーク121と、その外周部に固定された8個の永久磁石122を有する、8極のロータである(図2B参照)。
図15のホール素子群22、23の原点位置(T0)は、仮の原点位置であり、この位置は、本来、永久磁石原点位置(Z0)と一致すべきものである。
本実施例のブラシレスDCモータ10は、アウター型のロータ1000と、このロータ1000を回転自在に支持するステータ1200とから構成される。ロータ1000は、回転軸1300と、この回転軸1300が底面に固定されたカップ状のロータカバー1100と、ロータカバー1100の筒状部の内周面に沿って配置された複数極のマグネット1120とを備えている。一方、ステータ1200は、1対の軸受け16、17を介して回転軸1300を回転自在に支持する支持部材1205と、ロータ1000のマグネット1120の内側で半径方向のギャップを介して支持部材1205の筒状部1202にねじ等で固定されたステータコア1220と、このステータコア1220に巻回されたステータコイル1210とを備えている。支持部材1205には、外側からエンドカバー26が固定されている。回転軸1300の一端部及びエンドカバー26には、エンコーダ20が設けられている。
モータ制御ユニット30の機能は、実施例1のものとほぼ同じである。
すなわち、実施例4によれば、ブラシ付のDCモータにおいて、エンコーダは、回転軸の一端面に固定された平板状のマグネットと、これに対向してモータハウジングに設けられた3個のホール素子(H1-H3)からなる第1のホール素子群、及び、3個のホール素子(H4-H6)からなる第2のホール素子群、各ホール素子に共通の電圧Vccを印加する電源、及び、各ホール素子(H1-H6)に対応する増幅器25、26で構成される。エンコーダの出力は、第1、第2アブソリュート回転情報生成部310、320で処理される。なお、ブラシ付のDCモータの場合、マグネットのN極領域とS極領域の境界線上の位置に対応づけるべき回転軸の絶対原点位置Z0は、任意の位置に設定できる。そのため、実施例4のモータ制御ユニットは、実施例1の固定部材126及び固定ピン127が不要である。また、初期設定処理時に、実施例1の図9のステップ920に相当する処理を行う必要はない。モータ制御ユニットは、実施例1の図10に示した例のように、第1、第2ホール素子群の出力の振幅/角度変換処理後の平均値(h1-avg.)、(h2-avg.)と、位置決め情報(Sn、Ssn)の関係を取得し、これらの位置決め情報の中で、駆動信号のONデューティが零に同期する位置を、A相のパルスの立ち上がり時点に同期する、エンコーダの絶対原点位置とする。
すなわち、実施例4のモータ制御ユニットは、回転軸の絶対原点位置の抽出に関する機能を除いて、実施例1とほぼ同じ構成、機能を有する。
11 ステータコイル
12 ロータ
13 回転軸
14 減速機
16、17 軸受
18 第1のエンドカバー
19 第2のエンドカバー
20 エンコーダ
21 マグネット
22 第1のホール素子群
23 第2のホール素子群
24 ホール素子電源
25、26 増幅器
28 第1のホール素子群のアナログ出力
29 第2のホール素子群のアナログ出力
30 モータ制御ユニット
40 モータ駆動回路
42 主電源
48 給電端子
50 被駆動装置
100 モータ本体
111 界磁コイル
112 界磁鉄心
126 固定部材
127 固定ピン
310 第1のアブソリュート回転情報生成部
311 第1ホール素子出力処理部
3111 AD変換器
3112 軸ずれ補正処理部
3113 センサ異常判定部
3114 振幅/角度変換処理部
3115 平均角度値(h1-avg.)算出部
3116 平均角度値のパルスカウンタ
3117 インクリメンタルA相・B相信号生成部
3118 位置決め情報生成部
3119 バッファメモリ
312 センサ異常出力部
313 第1アブソリュート回転情報変換・記録部
314 原点位置設定部
315 位相同期処理部
316 Z相信号及び幅信号の生成部
317 メモリ制御部
320 第2のアブソリュート回転情報生成部
330 メモリ
340 モータ制御部
341 モータ制御信号生成部
342 駆動信号生成部
343 自己イニシャライズ処理部
344 サーボ制御部
345 センサ・モータ異常時処理部
346 メモリ制御部
350 モータ異常判定処理部
360 通信制御部
400 インバータ
410 インバータ駆動制御部
440 電流制御部
450 電流検出/制限部
460 位相検出部
470 電解コンデンサ
500 上位の制御装置
Claims (6)
- 駆動信号を生成して出力し、ブラシレスDCモータのU相、V相、W相の3相の各ステータコイルに供給される電力を制御する制御ユニットと、
多極の永久磁石を有するロータの回転を検知する1個のエンコーダとを有する、ブラシレスDCモータの制御装置において、
前記エンコーダは、
前記ロータの回転軸の一端に固定され、径方向に着磁された1組のN極領域とS極領域を有する平板状のマグネットと、該マグネットに対向する位置で前記モータのハウジング側に固定された、2組のホール素子群とを備えており、
前記2組のホール素子群は、
前記回転軸の回転中心を中心とする単一の円周上に、3個のホール素子が等間隔で配置された第1のホール素子群と、
前記第1のホール素子群と同じ円周上において、前記第1のホール素子群の中間に3個のホール素子が等間隔で配置された第2のホール素子群とを有しており、
前記制御ユニットは、
前記マグネットのN極領域とS極領域の境界線上の位置を、マグネット原点位置とし、前記2組のホール素子群の出力に基づいて、前記回転軸の回転に伴うA相、B相の信号を生成して出力するとともに、前記マグネットの原点位置の情報を生成する機能と、
前記ロータの極数に合わせて前記U相、V相、W相の各位相情報を生成する機能と、
前記ブラシレスDCモータのステータの各界磁コイルの磁極と電流の関係と前記駆動信号の零に対応する前記A相若しくは前記B相の出力信号の立ち上がり位相との同期関係に基づき、前記駆動信号に対する前記回転軸の絶対原点位置を取得する機能と、
前記A相、B相、及び、前記U相、V相、W相の各位相の情報を、前記回転軸の前記絶対原点位置を基準とするアブソリュート信号のデータに変換する機能とを備えており、
前記マグネットは前記原点位置が、前記回転軸の前記絶対原点位置と同期する位置に固定されており、
前記エンコーダを前記U相、V相、及びW相のロータリーエンコーダとして、前記アブソリュート信号に基づき前記モータを駆動するように構成されていることを特徴とするブラシレスDCモータの制御装置。 - 請求項1において、
前記第1、第2のホール素子群の各ホール素子は、同じ仕様を有しており、
前記制御ユニットは、
前記回転軸の1回転毎に、前記第1ホール素子群を構成する前記3個のホール素子の出力の平均値(h1-avg.)を算出して出力し、前記第2ホール素子群を構成する前記3個のホール素子の出力の平均値(h2-avg.)を算出して出力する機能と、
前記第1ホール素子群の出力の平均値及び前記第2ホール素子群の出力の平均値に基づき、各々、前記回転軸の回転に伴うA相、B相の信号を生成して出力する機能とを有することを特徴とするブラシレスDCモータの制御装置。 - 請求項2において、
前記第1、第2のホール素子群の各ホール素子は、同じ仕様を有しており、
前記制御ユニットは、1回転毎の前記各ホール素子H1-H3のいずれかの出力パルスが予め設定された閾値の範囲外である場合には、当該ホール素子に異常有りと判定し、センサ異常信号を出力する機能と、
正常な前記ホール素子群がある場合にその出力に基づくバックアップ制御等を行う機能とを有することを特徴とするブラシレスDCモータの制御装置。 - 請求項2において、
前記制御ユニットは、
前記第1、第2ホール素子群の出力に基づく前記アブソリュート信号を比較し、前記両アブソリュート信号の差分値が許容値を超えていれば、前記モータの異常と判定する機能と、
正常な前記ホール素子群がある場合にその出力に基づくバックアップ制御等を行う機能とを有することを特徴とするブラシレスDCモータの制御装置。 - 多極の永久磁石を有するロータの回転を検知する1個のエンコーダと、前記エンコーダの出力に基づいてロータの回転を制御する制御装置を備えた、ブラシレスDCモータであって、
請求項1-4のいずれか1項に記載の前記エンコーダと前記制御ユニットを備えていることを特徴とするブラシレスDCモータ。 - DCモータの駆動信号を生成して出力する制御ユニットと、
前記DCモータの回転軸の回転を検知するエンコーダとを備え、
前記駆動信号に基づき、前記回転軸に固定されたアマチュアにブラシを介して供給される電力を制御する、ブラシ付きDCモータの制御装置であって、
前記エンコーダは、
前記ロータの回転軸の一端に固定され、径方向に着磁された1組のN極領域とS極領域を有する平板状のマグネットと、該マグネットに対向する位置で前記モータのハウジング側に固定された、2組のホール素子群とを備えており、
前記2組のホール素子群は、
前記回転軸の回転中心を中心とする単一の円周上に、3個のホール素子が等間隔で配置された第1のホール素子群と、
前記第1のホール素子群と同じ円周上において、前記第1のホール素子群の中間に3個のホール素子が等間隔で配置された第2のホール素子群とを有しており、
前記制御ユニットは、
前記2組のホール素子群の出力に基づいて、前記回転軸の回転に伴うインクリメンタルなA相、B相の信号と、該A相、B相の出力信号が特定の関係にある状態を示す位置決め情報とを生成して出力する機能と、
前記マグネットのN極領域とS極領域の境界線上の位置をマグネット原点位置とし、前記駆動信号の零に対応する前記A相若しくは前記B相の出力信号の立ち上がり位相との同期関係に基づき、前記駆動信号に対する前記回転軸の絶対原点位置を取得する機能と、
前記A相、B相、及び、前記A相若しくは前記B相信号に基づくZ相の信号を生成する機能と、
前記A相、B相、及び前記Z相の情報を、前記回転軸の前記絶対原点位置を基準とするアブソリュート信号のデータに変換する機能とを備えており、
前記エンコーダをロータリーエンコーダとして、前記アブソリュート信号に基づき前記DCモータを駆動するように構成されていることを特徴とするDCモータの制御装置。
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CN114485738A (zh) * | 2022-01-06 | 2022-05-13 | 天津中德应用技术大学 | 一种双组霍尔传感器装置及其控制方法 |
CN114485738B (zh) * | 2022-01-06 | 2024-01-12 | 天津中德应用技术大学 | 一种双组霍尔传感器装置及其控制方法 |
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