JP2017158235A - Motor unit and motor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor unit capable of detecting a state of a motor while preventing an increase in size.SOLUTION: The motor unit includes: a motor having a driving coil and driven by a current supplied to the driving coil; a power receiving coil disposed so as to correspond to the motor and capable of receiving power supply from a power transmission coil by utilizing electromagnetic induction; and a determination unit that acquires information on electric power induced in the power receiving coil by an action of the driving coil and determines a state of the motor on the basis of the information on the electric power.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a motor unit, and more particularly to a motor unit having a power receiving coil.

  Some motor units detect the operating state of a motor in order to detect an abnormality. Regarding a technique for detecting an operation state of a motor, a motor unit disclosed in Japanese Patent Application Laid-Open No. 2011-041432 (Patent Document 1) identifies each magnet on the surface of a plurality of magnets of a rotor built in a brushless motor. A configuration is disclosed in which an RFID (Radio Frequency IDentifier) tag is fixed and an antenna that transmits an identification character of the RFID tag to an RFID reader is arranged in the stator. More specifically, the RFID reader discloses a configuration in which the magnet identification information received from the antenna and its position information are processed and transmitted to the motor control and drive unit.

JP 2011-041432 A

  Some motor units employ a non-contact power transmission method that has a power receiving coil and receives power supply from an external power transmitting coil to the power receiving coil using electromagnetic induction. Such a motor unit is used in, for example, an electric toothbrush, a robot, and the like, and downsizing is required.

  However, the technique disclosed in Patent Document 1 has a problem in that it is necessary to newly install devices such as an RFID tag, an antenna, and an RFID reader on the motor unit in order to detect the operation state of the motor, which prevents miniaturization. .

  This indication is made in order to solve the above problems, and the objective in a certain situation is to provide the motor unit which can detect the state of a motor, preventing enlargement. .

  According to an aspect of the invention, the motor unit has a drive coil, and is arranged to correspond to the motor that is driven when current is supplied to the drive coil, and electromagnetic induction is performed from the power transmission coil. A power receiving coil capable of receiving power supply by using, and a determination unit that obtains information on the power induced in the power receiving coil by the action of the drive coil and determines the state of the motor based on the power information With.

  According to the motor unit according to the embodiment, it is possible to detect the state of the motor while preventing an increase in size.

It is a figure which compares and demonstrates the motor unit according to a related technique, and the motor unit according to embodiment. It is a figure explaining the structural example of the motor unit according to Embodiment 1. FIG. It is a figure explaining the relationship between the receiving coil according to Embodiment 1, and a motor main body. It is a figure explaining the external appearance structural example of the motor unit according to Embodiment 1. FIG. It is a figure explaining the induced electromotive force induced | guided | derived to a receiving coil at the time of the drive of the motor main body according to Embodiment 1. FIG. It is a figure explaining the induced electromotive force induced | guided | derived to a receiving coil at the time of charge of the motor main body according to Embodiment 1. It is a flowchart explaining the determination method of the operation state of a motor main body and the charge state of a battery of the motor unit according to the first embodiment. 5 is a flowchart for describing abnormality determination of a motor unit according to the first embodiment. It is a figure explaining the frequency spectrum of the induced electromotive force according to the state of a motor main body and a battery according to Embodiment 2. It is a flowchart explaining the determination method of the operation state of a motor main body, and the charge state of a battery of the motor unit according to Embodiment 2. It is a figure explaining the control outline | summary of the motor unit according to Embodiment 3. It is a figure explaining the relationship between the motor main body according to the modification 1, and a receiving coil.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[A. Introduction]
(A1. Related technology)
FIG. 1 is a diagram illustrating a comparison between a motor unit 100X according to the related art and a motor unit 100 according to the embodiment. Referring to FIG. 1A, a motor unit 100X according to related technology includes a control unit 10, a communication unit 20, a motor main body 30, a battery 40, a wireless power feeding module 50, and a motor state monitoring module 60. Have.

  The control unit 10 adjusts the amount of power supplied from the battery 40 to the motor main body 30 based on the control signal input via the communication unit 20. The motor body 30 drives a load connected to a rotating shaft 32 described later. The wireless power supply module 50 includes a power receiving coil 52 and a power supply control unit 54. The power receiving coil 52 receives power supply from the power transmitting coil 200 provided outside the motor unit 100X using electromagnetic induction. The power supply control unit 54 converts AC power induced in the power receiving coil into DC power and supplies the converted DC power to the battery 40.

  The motor state monitoring module 60 includes, for example, a sensor such as a Hall element, detects the position of the rotor built in the motor main body 30 by the sensor, and transmits the detection result to the control unit 10. Based on the signal received from the motor state monitoring module 60, the control unit 10 can grasp the operation state of the motor body 30 such as whether or not the motor body 30 is driven.

  However, the motor unit 100X according to the related art needs to be equipped with additional devices such as a sensor and an encoder in order to grasp the operation state of the motor body 30. By mounting these devices, there is a problem that the motor unit 100X according to the related technology is increased in size. Therefore, an outline of the motor unit 100 according to the embodiment that can grasp the operation state of the motor without mounting an additional device will be described below.

(A2. Overview of Motor Unit According to Embodiment)
Referring to FIG. 1B, the motor unit 100 according to the embodiment does not have the motor state monitoring module 60 as compared with the motor unit 100 </ b> X according to the related art, but instead of the motor state monitoring module 60. Monitor information. The power information includes, for example, the magnitude or waveform of the current or voltage flowing through the power receiving coil 52, the frequency, and the like.

  In addition, the power receiving coil 52 according to the embodiment is disposed so as to correspond to the motor main body 30. Thereby, when the motor main body 30 is driven, in other words, when a current flows through the drive coil 34 of the motor main body 30, AC power is induced in the power receiving coil 52 by electromagnetic induction. The control unit 10 according to the embodiment grasps the operating state of the motor main body 30 by monitoring information on the power induced in the power receiving coil 52 by the action of the drive coil 34.

  According to the above, the motor unit 100 according to the embodiment can grasp the operating state of the motor main body 30 by using the power receiving coil 52 without mounting an additional device such as a Hall element. . Therefore, the motor unit 100 according to the embodiment can detect the state of the motor while suppressing an increase in size. In addition, since the motor unit 100 according to the embodiment can use an existing motor without additionally installing a device such as an RFID tag in the motor body 30, it is highly versatile and can reduce production costs. . Hereinafter, the configuration and control details of the motor unit 100 according to the embodiment will be described.

[B. Embodiment 1]
(B1. Configuration of the motor unit 100)
FIG. 2 is a diagram illustrating a configuration example of the motor unit 100 according to the first embodiment. FIG. 2A illustrates the operation of the motor unit 100 during charging, and FIG. 2B illustrates the operation of the motor unit 100 during driving.

  2A, the motor unit 100 according to the first embodiment includes a control unit 10, a communication unit 20, a motor main body 30, a battery 40, a power receiving coil 52, and a power supply control unit 54. . The control unit 10 includes an acquisition unit 12 that is electrically connected to the power receiving coil 52. The acquisition unit 12 monitors the induced electromotive force Vin induced in the power receiving coil 52. In the first embodiment, the motor body 30 is assumed to be a brush motor as an example.

  A charging device including a power transmission coil 200 and a power supply control unit 210 is disposed outside the motor unit 100. When charging the battery 40, the motor unit 100 is disposed in contact with or close to the charging device. When a current flows through the power transmission coil 200 in this state, a magnetic flux is generated so as to penetrate the power transmission coil 200. When the magnetic flux penetrates the power receiving coil 52, AC power is induced in the power receiving coil 52. The AC power induced in the power receiving coil 52 is rectified and smoothed into DC power by the power supply control unit 54 and supplied to the battery 40.

  On the other hand, driving of the motor body 30 will be described with reference to FIG. When the control unit 10 receives a control signal for driving the motor main body 30 from an external device (for example, a personal computer) via the communication unit 20, a current flows from the battery 40 to the drive coil 34 built in the motor main body 30. To control.

  Here, the power receiving coil 52 of the motor unit 100 according to the first embodiment is arranged so as to correspond to the motor main body 30. More specifically, the power reception coil 52 is disposed so that the power reception coil 52 penetrates at least part of the magnetic flux generated by the current flowing from the battery 40 to the drive coil 34.

  Thereby, when a current flows through the drive coil 34, AC power is induced in the power receiving coil 52 by electromagnetic induction. The control unit 10 monitors the induced electromotive force Vin induced in the power receiving coil 52 to grasp the operation state of the motor body 30 such as whether or not the motor body 30 is driven.

  FIG. 3 is a diagram illustrating the relationship between the power receiving coil 52 and the motor main body 30 according to the first embodiment. Referring to FIG. 3, motor main body 30 includes commutators 31a and 31b, rotating shaft 32, rotor 33, drive coil 34, magnets 35a and 35b, and opposing electrodes as main components. And a brush 37 including the same. The motor body 30 discloses a configuration having two commutators in the example shown in FIG. 3, but is not limited thereto, and may have a configuration having three or more commutators in other aspects. .

  The power reception coil 52 is configured such that the axis of the power reception coil 52 is orthogonal to the rotation axis 32 of the motor body 30. The power receiving coil 52 is disposed in contact with or close to the motor body 30. Preferably, the power receiving coil 52 is disposed such that the distance from the motor body 30 is 1 cm or less.

  FIG. 4 is a diagram illustrating an external configuration example of the motor unit 100 according to the first embodiment. Referring to FIG. 4, motor unit 100 houses devices such as control unit 10, communication unit 20, motor main body 30, battery 40, power reception coil 52, and the like described above in a casing 70 that is substantially cubic. As an example, the length of each side of the housing 70 is configured to be 54 mm in the longitudinal direction of the rotation shaft 32 of the motor body 30 and 52 mm in each direction orthogonal to the longitudinal direction.

  The power receiving coil 52 is disposed between the motor main body 30 and the outer wall constituting the housing 70. From the viewpoint of miniaturization of the motor unit 100, the outer diameter of the power receiving coil 52 is substantially equal to the distance in the longitudinal direction of the rotor 33 orthogonal to the rotation shaft 32 (hereinafter also referred to as “the outer diameter of the motor body 30”). Is preferred. More specifically, the outer diameter of the power receiving coil 52 is preferably configured to be not less than 0.5 times and not more than 2.0 times the outer diameter of the motor body 30. In another aspect, the outer diameter of the motor body 30 may be the distance of the housing of the motor body 30 in the longitudinal direction of the rotor 33.

  Referring to FIG. 3 again, when a current flows from the battery 40 to the drive coil 34 via the brush 37, the rotor 33 is magnetized and rotated by being attracted to the magnets 35a and 35b. Therefore, the power receiving coil 52 is induced with an induced electromotive force Vin by the action of the drive coil 34 over a predetermined phase period in the rotational motion of the rotor 33.

(B2. Behavior of induced electromotive force Vin)
FIG. 5 is a diagram for explaining the induced electromotive force Vin induced in the power receiving coil 52 when the motor main body 30 according to the first embodiment is driven. Referring to FIG. 5A, when a predetermined time (for example, 1 second) elapses after the motor main body 30 starts driving, the rotational speed of the rotor 33 is stabilized. That is, when a predetermined time elapses after the motor body 30 starts driving, the induced electromotive force Vin induced in the power receiving coil 52 is stabilized. In this state, the induced electromotive force Vin induced in the power receiving coil 52 becomes the voltage Vamp1 in a predetermined phase period in which the rotor 33 approaches the power receiving coil 52, and becomes minus Vamp1 in a predetermined phase period in which the rotor 33 leaves. The induced electromotive force Vin repeats the above behavior every time the rotor 33 rotates 180 °. If the maximum voltage of the induced electromotive force Vin during a predetermined phase period during which the rotor 33 rotates at least 180 ° is defined as Vamp, the maximum voltage Vamp during driving of the motor body 30 is the voltage Vamp1. The maximum voltage Vamp is information associated with the amplitude of the induced electromotive force Vin. On the other hand, when the motor main body 30 is stopped, the induced electromotive force Vin in the power receiving coil 52 is 0 or substantially 0, and thus the maximum voltage Vamp is also 0 or substantially 0.

  Using this characteristic, the control unit 10 calculates the maximum voltage Vamp from the induced electromotive force Vin acquired by the acquisition unit 12, and determines the region where the maximum voltage Vamp exists, thereby operating the motor body 30. The state can be determined.

  FIG. 5B is a diagram for explaining the relationship between the maximum voltage Vamp and the operation state of the motor body 30. The control unit 10 compares the calculated maximum voltage Vamp with the threshold voltage Vth1 that is greater than 0 and less than the voltage Vamp1. When it is determined that the maximum voltage Vamp is less than the threshold voltage Vth1, the control unit 10 determines that the motor body 30 is stopped. On the other hand, when determining that the maximum voltage Vamp is equal to or higher than the threshold voltage Vth1, the control unit 10 determines that the motor body 30 is being driven. Based on the above, the motor unit 100 according to the first embodiment can determine whether or not the motor main body 30 is driven based on the maximum voltage Vamp associated with the amplitude of the induced electromotive force Vin.

  In another aspect, the control unit 10 acquires information on the induced electromotive force induced in the power receiving coil 52 by the action of the power transmitting coil 200, and the power receiving state of the power receiving coil 52 from the power transmitting coil 200 based on the information. That is, a configuration in which the state of charge of the battery 40 is further determined may be used.

  FIG. 6 is a diagram illustrating an induced electromotive force Vin induced in the power receiving coil 52 when the motor main body 30 according to the first embodiment is charged. With reference to FIG. 6A, the induced electromotive force induced by the action of the power transmission coil 200 is independent of the rotational motion of the rotor 33. Therefore, the induced electromotive force Vin is induced in the power receiving coil 52 as long as a current flows through the power transmitting coil 200 and the power receiving coil 52 and the power transmitting coil 200 are arranged close to or in contact with each other. When the peak value of the induced electromotive force induced in the power reception coil 52 by the action of the power transmission coil 200 is defined as the voltage Vc, the maximum voltage Vamp during charging of the battery 40 is the voltage Vamp1. The voltage Vc is significantly larger than the voltage Vamp1. The controller 10 further determines the state of charge of the battery 40 from the maximum voltage Vamp using this characteristic.

  Referring to FIG. 6B, in addition to threshold voltage Vth1, control unit 10 compares threshold voltage Vth2 exceeding voltage Vamp1 and less than voltage Vc with maximum voltage Vamp. Specifically, when determining that the maximum voltage Vamp is equal to or higher than the threshold voltage Vth1 and lower than the threshold voltage Vth2, the control unit 10 determines that the motor body 30 is being driven. Further, when determining that the maximum voltage Vamp is equal to or higher than the threshold voltage Vth2, the control unit 10 determines that the battery 40 is being charged. Based on the above, the control unit 10 can further determine the power reception state of the power reception coil 52 from the power transmission coil 200 based on the information on the power induced in the power reception coil 52 by the action of the power transmission coil 200.

  FIG. 7 is a flowchart illustrating a method for determining the operating state of motor body 30 and the charging state of battery 40 in motor unit 100 according to the first embodiment. The processing shown in FIG. 7 is realized by the control unit 10 executing a control program stored in a storage unit (not shown). In other aspects, some or all of the processing may be performed by circuit elements or other hardware. These conditions are the same in the flowcharts shown below.

  Referring to FIG. 7, in step S <b> 10, control unit 10 calculates maximum voltage Vamp from the waveform of induced electromotive force Vin induced in power reception coil 52 acquired by acquisition unit 12.

  In step S12, the control unit 10 determines whether or not the calculated maximum voltage Vamp is less than the threshold voltage Vth1. When controller 10 determines that maximum voltage Vamp is less than threshold voltage Vth1 (YES in step S12), controller 10 determines that motor body 30 is in a stopped state (step S14). On the other hand, when control unit 10 determines that maximum voltage Vamp is equal to or higher than threshold voltage Vth1 (NO in step S12), the process proceeds to step S16.

  In step S16, the control unit 10 determines whether or not the maximum voltage Vamp is less than the threshold voltage Vth2. When controller 10 determines that maximum voltage Vamp is less than threshold voltage Vth2 (YES in step S16), controller 10 determines that motor body 30 is in a driving state (step S18). On the other hand, when controller 10 determines that maximum voltage Vamp is equal to or higher than threshold voltage Vth2 (NO in step S16), controller 10 determines that battery 40 is being charged (step S20). .

  Based on the above, the motor unit 100 according to the first embodiment can determine the operating state of the motor main body 30 and the charged state of the battery 40 based on the induced electromotive force Vin induced in the power receiving coil 52. That is, since the motor unit 100 according to the first embodiment can determine the operation state of the motor main body 30 without mounting an additional device such as a Hall element, an increase in size can be prevented.

  In addition, the motor unit 100 according to the first embodiment can determine the operation state of the motor without using a special motor equipped with an RFID tag or the like, even when using an existing motor. The production cost can be reduced.

(B3. Abnormality notification)
Next, a method for detecting an abnormality of the motor unit 100 using the above state determination will be described. FIG. 8 is a flowchart illustrating abnormality determination of motor unit 100 according to the first embodiment. Referring to FIG. 8, in step S <b> 30, control unit 10 receives an operation signal for operating motor body 30 from an external device via communication unit 20. Thereby, the control unit 10 performs control so that electric power is supplied from the battery 40 to the motor main body 30.

  In step S <b> 32, the control unit 10 determines whether or not a predetermined time has elapsed until the rotation speed of the rotor 33 is stabilized. If control unit 10 determines that a predetermined time has elapsed after receiving the input of the control signal from the external device (YES in step S32), the process proceeds to step S34. On the other hand, when control unit 10 determines that the predetermined time has not elapsed since receiving the input of the control signal from the external device (NO in step S32), the process returns to step S32.

  In step S34, the control unit 10 calculates the maximum voltage Vamp from the waveform of the induced electromotive force Vin.

  In step S36, the control unit 10 determines whether or not the motor main body 30 is being driven. Specifically, the control unit 10 determines whether or not the motor main body 30 is driven by executing the processing shown in FIG. That is, the control unit 10 determines that the motor body 30 is driven when it is determined that the calculated maximum voltage Vamp is greater than or equal to the threshold voltage Vth1 and less than the threshold voltage Vth2.

  If it is determined that motor body 30 is driving (YES in step S36), control unit 10 advances the process to step S38 and notifies the external device of a signal indicating that motor body 30 is driving normally. .

  On the other hand, when it is determined that the motor main body 30 is not driven (NO in step S36), the control unit 10 advances the process to step S40, and the motor main body 30 is in spite of the operation signal being input from the external device. An error signal is notified to the external device as not being driven.

(B4. Estimation of the rotational speed of the motor based on the induced electromotive force Vin)
In the above example, the motor unit 100 is configured to simply determine whether or not the motor body 30 is driven based on the induced electromotive force Vin. Next, a configuration for estimating the rotational speed of the rotor 33 (rotary shaft 32) built in the motor main body 30 (hereinafter also referred to as “rotational speed of the motor main body 30”) based on the induced electromotive force Vin will be described. .

  Referring to FIG. 5A again, the control unit 10 calculates the cycle T1 of the induced electromotive force Vin from the waveform of the induced electromotive force Vin acquired by the acquisition unit 12.

  Next, the control unit 10 calculates the frequency fd of the induced electromotive force Vin induced in the power receiving coil 52 by the action of the drive coil 34 from the cycle T1. Subsequently, the control unit 10 calculates the rotation speed of the motor body 30 by multiplying the frequency fd by the proportional coefficient C.

  As described above, the rotational speed of the rotor 33 is proportional to the frequency fd (inversely proportional to the period T1). Therefore, the shorter the period T1, the higher the rotational speed of the motor body 30. It is assumed that the proportional coefficient C is stored in a storage unit (not shown) included in the control unit 10. The proportionality coefficient C indicates a value that varies depending on the configuration of the motor body 30. Therefore, it is preferable to calculate a proportional coefficient C determined in advance from the rotational speed of the rotor 33 and the frequency fd and store it in the storage unit.

  Based on the above, the motor unit 100 according to the first embodiment can estimate the rotational speed of the motor body 30 based on the induced electromotive force Vin induced in the power receiving coil 52. In addition, the control unit 10 according to the first embodiment is configured to notify an external device of an error when the estimated rotation speed of the motor body 30 is out of a predetermined rotation speed range stored in the storage unit. There may be.

  In the above example, the motor unit includes a battery, but is not limited thereto. In another aspect, the motor unit may be configured to supply the electric power induced in the power receiving coil to the motor body via the power supply control unit without storing the electric power in the battery. Also in this configuration, the motor unit can determine the operating state of the motor body based on the induced electromotive force induced in the power receiving coil.

[C. Embodiment 2]
The motor unit 100 according to the first embodiment is configured to determine the state of the motor main body 30 from the induced electromotive force Vin induced in the power receiving coil 52 by the action of the drive coil 34. In general, the frequency fc of the induced electromotive force induced in the power receiving coil 52 by the action of the power transmission coil 200 is significantly higher than the frequency fd of the induced electromotive force induced by the action of the drive coil 34. For example, in the case of Qi, which is an international standard for the non-contact power transmission method, the frequency fc is set to 110 kHz to 205 kHz. On the other hand, the frequency fd is, for example, about several hundred Hz to several kHz. The motor unit 100 according to the second embodiment determines the states of the motor main body 30 and the battery 40 using the difference between the frequency fc and the frequency fd. Since the basic configuration of motor unit 100 according to the second embodiment is substantially the same as the basic configuration of motor unit 100 according to the first embodiment, only different parts will be described.

  FIG. 9 is a diagram illustrating the frequency spectrum of the induced electromotive force Vin according to the states of the motor main body 30 and the battery 40 according to the second embodiment. FIG. 9A is a frequency spectrum of the induced electromotive force Vin when the motor body 30 is being driven and the battery 40 is not being charged. As shown in FIG. 9A, the induced electromotive force Vin under the above conditions has a peak frequency fd in a frequency range of 10 kHz or less.

  FIG. 9B is a frequency spectrum of the induced electromotive force Vin when the motor main body 30 is stopped and the battery 40 is being charged. As shown in FIG. 9B, the induced electromotive force Vin under the condition has a peak frequency fc in a range where the frequency is 20 kHz or more.

  FIG. 9C is a frequency spectrum of the induced electromotive force Vin when the motor main body 30 is being driven and the battery 40 is being charged. As shown in FIG. 9 (c), the induced electromotive force Vin under the condition has a peak frequency fd in a frequency range of 10 kHz or less and a peak frequency fc in a range of 20 kHz or more.

  The motor unit 100 according to the second embodiment determines the states of the motor body 30 and the battery 40 using the above characteristics. More specifically, the control unit 10 according to the second embodiment performs a Fourier transform process on the induced electromotive force Vin per unit period acquired by the acquisition unit 12 to calculate a peak frequency. As an example, the unit period is a period in which the rotor 33 rotates at least 180 ° in a state where the rotation speed of the rotor 33 is stable. The control unit 10 determines the state of the motor body 30 and the battery 40 by determining in which frequency range the peak frequency exists. As an example, the control unit 10 determines that the motor body 30 is being driven when the calculated peak frequency is in the frequency range of 10 kHz or less, and the battery 40 is in the frequency range of 20 kHz to 1000 kHz. It is determined that charging is in progress.

  At this time, the control unit 10 may make the determination using only the peak frequency equal to or higher than the predetermined intensity in order to increase the accuracy of the determination. For example, the control unit 10 is configured to use only the peak frequency exceeding the threshold strength Ith1 in the range of 10 kHz or less, and to use only the peak frequency exceeding the threshold strength Ith2 in the range of 20 kHz or more. Also good.

  According to the above, the motor unit 100 according to the second embodiment can determine the states of the motor main body 30 and the battery 40 based on the frequency spectrum of the induced electromotive force Vin.

  The determination method according to the first embodiment is based on the maximum voltage Vamp of the induced electromotive force Vin. However, the maximum voltage Vamp varies depending on the distance between the power transmission coil 200 and the power reception coil 52. For this problem, the peak frequency of the induced electromotive force Vin does not depend on the distance. Therefore, the motor unit according to the second embodiment can determine the states of the motor main body 30 and the battery 40 with higher accuracy than the motor unit according to the first embodiment.

  Hereinafter, the series of determination methods will be described with reference to FIG. FIG. 10 is a flowchart illustrating a method for determining the operating state of motor body 30 and the charging state of battery 40 in motor unit 100 according to the second embodiment. In addition, since it is the same about the part which attached | subjected the same code | symbol as FIG. 7, the description about the part is not repeated.

  Referring to FIG. 10, in step S50, control unit 10 acquires a waveform of induced electromotive force Vin induced in power receiving coil 52 from acquisition unit 12 over a unit period. In step S52, the control unit 10 performs a fast Fourier transform (FFT) process on the acquired induced electromotive force Vin, and calculates a frequency spectrum of the induced electromotive force Vin.

  In step S54, the control unit 10 calculates a peak frequency from the frequency spectrum of the induced electromotive force Vin. In step S56, the control unit 10 determines whether or not a peak frequency exists in the first frequency range. As an example, the first frequency range is 20 kHz or more and 1000 kHz or less. That is, in step S56, the control unit 10 determines whether or not the battery 40 is being charged. If control unit 10 determines that no peak frequency exists in the first frequency range (NO in step S56), the process proceeds to step S58. On the other hand, when control unit 10 determines that the peak frequency is present in the first frequency range (YES in step S56), the process proceeds to step S60.

  In steps S58 and S60, the control unit 10 determines whether or not a peak frequency exists in the second frequency range. As an example, the second frequency range is 0 Hz to 10 kHz. That is, the control unit 10 determines whether or not the motor main body 30 is being driven in steps S58 and S60.

  When determining in step S58 that the peak frequency does not exist in the second frequency range, the control unit 10 determines that the motor body 30 is stopped and the battery 40 is not being charged (step S62). ). On the other hand, when determining in step S58 that the peak frequency is present in the second frequency range, the control unit 10 determines that the motor body 30 is being driven and the battery 40 is not being charged (step S58). S64).

  When determining in step S60 that the peak frequency does not exist in the second frequency range, the control unit 10 determines that the motor body 30 is stopped and the battery 40 is being charged (step S66). ). On the other hand, when determining in step S60 that the peak frequency is present in the second frequency range, the control unit 10 determines that the motor main body 30 is being driven and the battery 40 is being charged (step S60). S68).

  According to the above, the motor unit 100 according to the second embodiment can determine the states of the motor main body 30 and the battery 40 based on the frequency spectrum of the induced electromotive force Vin.

[D. Embodiment 3]
The motor unit according to the first embodiment is configured to determine whether or not the motor main body 30 is driven based on the maximum voltage Vamp of the induced electromotive force Vin. The motor unit according to the third embodiment not only determines whether the motor main body 30 is driven based on the maximum voltage Vamp, but also estimates a more detailed operation state of the motor main body 30. Note that the basic configuration of the motor unit 100 according to the third embodiment is substantially the same as the basic configuration of the motor unit 100 according to the first embodiment, and therefore only different parts will be described.

  FIG. 11 is a diagram illustrating an outline of control of the motor unit 100 according to the third embodiment. Referring to FIG. 11, a load 400 is connected to the rotating shaft 32 constituting the motor main body 30. As the load torque of the load 400 increases, the current flowing through the drive coil 34 of the motor body 30 also increases. Using this characteristic, the control unit 10 according to the third embodiment estimates the size of the load 400 from the size of the maximum voltage Vamp of the induced electromotive force Vin.

  When estimating the load 400 with higher accuracy, the storage unit of the control unit 10 stores the relationship between the amplitude of the induced electromotive force Vin (maximum voltage Vamp) measured in advance and the magnitude of the load connected to the rotating shaft. Represents a table or formula that represents. The control unit 10 can calculate the maximum voltage Vamp from the induced electromotive force Vin acquired by the acquisition unit 12, and can estimate the size of the load 400 from the above relationship. Based on the above, the motor unit 100 according to the third embodiment can estimate the magnitude of the load connected to the motor body 30 based on the magnitude of the induced electromotive force Vin induced in the power receiving coil 52.

[E. Modification 1—Brushless Motor]
Although the motor unit 100 according to the first to third embodiments has a configuration in which a brush motor is mounted as the motor body 30, the invention is not limited thereto. The motor unit 100 </ b> A according to the first modification includes a motor main body 30 </ b> A that is a brushless motor instead of the motor main body 30. Even with such a configuration, the motor unit 100A according to the first modification can perform the same control as in the first to third embodiments. Note that the basic configuration of the motor unit 100A according to the first modification is substantially the same as the basic configuration of the motor unit 100 according to the first embodiment, and therefore only different parts will be described.

  FIG. 12 is a diagram for explaining the relationship between the motor main body 30A and the power receiving coil 52 according to the first modification. The motor body 30A, which is a brushless motor, includes a rotating shaft 32, a two-pole rotor 33A, magnets 35A, 35B, and 35C, drive coils 34A, 34B, and 34C disposed in each magnet, an inverter circuit 38, and a rotor. And Hall elements 39 arranged at intervals of 120 ° around 33.

  The power receiving coil 52 is disposed so as to correspond to an arbitrary driving coil among the driving coils 34A, 34B, and 34C. In the example shown in FIG. 12, the power receiving coil 52 is disposed so as to correspond to the drive coil 34A. More specifically, the power reception coil 52 is disposed so that the axis of the power reception coil 52 is orthogonal to the rotation shaft 32 of the motor body 30A. The power receiving coil 52 is disposed in contact with or close to the motor main body 30A.

  In this configuration, when the motor main body 30A is driven in the power receiving coil 52 according to the first modification, in other words, when a current flows through the drive coil 34A, an induced electromotive force Vin is generated by the action of the drive coil 34A. In the example shown in FIG. 12, the motor main body 30A is a three-phase motor. Accordingly, the inverter circuit 38 applies a positive predetermined current to the drive coil 34A every time the rotor 33A rotates 120 ° based on the positional information of the rotor 33A input from the Hall element 39, and a negative predetermined Switching between a state where current is applied and a state where no current is applied. The induced electromotive force Vin induced in the power receiving coil 52 changes according to the current applied to the drive coil 34A.

  The control unit 10 according to the modified example 1 monitors the induced electromotive force Vin induced in the power receiving coil 52, so that the frequency of the induced electromotive force Vin and the induced electromotive force Vin in the phase period in which the rotor 33A rotates 360 ° are measured. The maximum voltage Vamp is calculated. Based on these parameters, the control unit 10 can determine the operating state of the motor main body 30A and the charged state of the battery 40, as in the first to third embodiments. In addition, it is preferable that the control unit 10 calculates the above frequency and the maximum voltage Vamp in a state where the rotation speed of the rotor 33A is stable.

  According to the above, the motor unit 100A according to the first modification can determine the operating state of the brushless motor and the charged state of the battery even if the motor is a brushless motor. In addition, although the motor unit 100A according to the modified example 1 can grasp the operating state of the motor main body 30A using the Hall element 39, there is a possibility that a problem may occur. The Hall element 39 does not operate normally in a high temperature (for example, 120 ° C. or higher) environment. Also, the environmental temperature to which the Hall element 39 is exposed often exceeds 120 ° C. Therefore, the motor unit 100A according to the first modification can accurately determine the operating state of the motor main body 30A even under a high temperature environment by using the induced electromotive force Vin induced in the power receiving coil 52.

[F. Modification 2-Induction Current]
The motor unit 100 according to the first to third embodiments is configured to determine the states of the motor body 30 and the battery 40 based on the induced electromotive force Vin that is a voltage induced in the power receiving coil 52. In another aspect, the motor unit 100 may monitor the induced current Iin induced in the power receiving coil 52 instead of the induced electromotive force Vin. In this case, the motor unit 100 calculates the frequency of the induced current Iin and the maximum current value Iamp in a predetermined phase period from the waveform of the induced current Iin, and the operation of the motor main body 30 as in the first to third embodiments. The state and the state of charge of the battery 40 are determined.

[G. Summary]
The motor unit according to the embodiment, based on the induced electromotive force or induced current induced in the receiving coil, in other words, based on the information on the electric power induced in the receiving coil, determines the motor operating state and the battery charging state. Can be determined.

  In addition, the motor unit according to the embodiment can make the above determination using a power receiving coil arranged to receive power supply from the outside. Therefore, since the motor unit according to the embodiment can determine the state of the motor unit without mounting an additional device, the size of the unit can be suppressed.

  Moreover, since the motor unit according to the embodiment does not include an additional unit, the production cost can be suppressed. Furthermore, the motor unit according to the embodiment does not need to use a special motor (for example, a motor in which an RFID tag is embedded in the rotor), and can use a general motor, and thus has high versatility.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In addition, it should be considered that the above-described Embodiments 1 to 3, Modification 1 and Modification 2 can be arbitrarily combined. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 Control part, 12 acquisition part, 30, 30A motor main body, 32 rotating shaft, 33, 33A rotor, 34, 34A, 34B, 34C drive coil, 35A, 35B, 35C, 35a magnet, 37 brush, 38 inverter circuit, 40 Battery, 52 power receiving coil, 54 power supply control unit, 60 motor state monitoring module, 70 housing, 100, 100A, 100X motor unit, 200 power transmission coil.

Claims (14)

A motor having a drive coil and driven by supplying current to the drive coil;
A power receiving coil arranged to correspond to the motor and capable of receiving power supply from the power transmitting coil using electromagnetic induction;
A motor unit comprising: a determination unit that acquires information on the power induced in the power receiving coil by the action of the drive coil and determines the state of the motor based on the information on the power.   The motor unit according to claim 1, wherein the power receiving coil is disposed such that a distance between the power receiving coil and the motor is 1 cm or less.   The motor unit according to claim 1, wherein the power reception coil is disposed such that an axis of the power reception coil is orthogonal to a rotation axis of the motor.   4. The power receiving coil according to claim 1, wherein an outer diameter of the power receiving coil is configured to be not less than 0.5 times and not more than 2.0 times the outer diameter of the motor. Motor unit.   The motor unit according to claim 1, wherein the determination unit determines that the motor is in a driving state when a value of the power information is within a predetermined range. The power information includes information associated with the amplitude of AC power induced in the power receiving coil,
The motor unit according to claim 5, wherein the determination unit determines whether or not the motor is in a driving state based on whether or not a value of information associated with the amplitude is within a predetermined range. .   The determination unit calculates a peak frequency by performing Fourier transform on the information on the power per unit period, and determines whether the motor is based on whether the peak frequency is within a predetermined range. The motor unit according to claim 5, wherein it is determined whether or not it is in a driving state. The power information includes the frequency of AC power induced in the power receiving coil by the action of the drive coil,
The motor unit according to claim 1, wherein the determination unit calculates a rotation speed of the motor based on the frequency when it is determined that the motor is in a driving state. The power information includes information associated with the amplitude of AC power induced in the power receiving coil,
The motor unit according to claim 1, wherein the determination unit estimates the magnitude of a load connected to the motor based on information associated with the amplitude.   The said determination part further acquires the information of the electric power induced by the said receiving coil by the effect | action of the said transmitting coil, and further determines the receiving state from the said transmitting coil based on the information of the said electric power. 10. The motor unit according to any one of 9 above.   The motor unit according to claim 1, wherein the motor is one of a brush motor and a brushless motor.   The motor unit according to any one of claims 1 to 11, further comprising a storage battery for storing electric power induced in the power receiving coil by the action of the power transmitting coil and supplying the electric power to the driving coil. A housing for accommodating the power receiving coil, the storage battery, the motor, and the determination unit;
The motor unit according to claim 12, wherein the power reception coil is disposed between the motor and the housing.   A motor system comprising the motor unit according to claim 1 and a charging device including the power transmission coil.

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