KR102558996B1 - In-wheel type dual motor device for personal mobility - Google Patents

Abstract

The in-wheel type dual motor device includes a stator having a first winding set and a second winding set, a rotor rotating by electromagnetic interaction with the stator, a first driver supplying a first driving current to the first winding set, a second driver supplying a second driving current to the second winding set, a 9-axis sensor measuring values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism, and a 3-dimensional motion measured by the 9-axis sensor It is characterized in that it includes a controller that independently controls the operation of the first driver and the second driver.

Description

In-wheel type dual motor device for personal mobility {In-wheel type dual motor device for personal mobility}

The present invention relates to a motor device, and more particularly, to an in-wheel type dual motor device for personal mobility.

Transportation using an internal combustion engine using fossil fuels appeared at the end of the 19th century and became a trend in the transportation market through World Wars I and II, and continued to develop while expanding the market.

However, since the mid-20th century, environmental pollution problems have emerged, and thanks to the high efficiency of electric motors (motors) and the improvement of battery technology, various personal transportation means (personal mobility) using electric motors have begun to appear.

Accordingly, in Korea, the development and distribution of motorized scooters, motorcycles, automobiles, etc. are expanding due to social interest in environmental protection and policy support for transportation means that can replace internal combustion engines.

Due to the nature of more than 60% of Korea's land area being mountainous, there are many sloping roads in both cities and countryside. Due to these topographical factors, it was difficult to spread electric bicycles and scooters in the early days.

In the case of the early model, there are problems of reduced battery utilization efficiency and price increase as a large-capacity motor is required when driving on a slope with a motor suitable for flat terrain.

In the case of a large-capacity motor, battery consumption increases compared to a motor with an appropriate amount when driving in a flat area, and due to the motor driver corresponding to the large-capacity motor, it is an additional price increase factor.

Accordingly, attempts have been made to respond to large-capacity motors by using two small-volume motors, and in most cases, motors are mounted on the front and rear wheels, respectively.

When using two front and rear motors that are interlocked according to driving conditions, it is necessary to properly distribute torque to the front and rear wheels and control the rotational speed according to the state of road grip (resistance between tire and road surface) and the movement of the center of gravity.

In addition, since the center of gravity moves to the rear when accelerating, it is necessary to control the torque and power of the front wheel motor to be lowered in order to prevent the front wheel from slipping.

When the electric motor is installed on the front wheel, it is necessary to set the power line and sensor line path in consideration of the axial direction change of the wheel, so there is a problem that the durability of the power line and sensor line is weakened due to the axial direction change.

KR 10-2018-0070141 A

The present invention has been proposed to solve the above technical problems, and provides an in-wheel type dual motor device in which a plurality of winding sets are mounted on one motor applied to one axis.

According to an embodiment of the present invention for solving the above problems, a stator having a first winding set and a second winding set, a rotor rotating by electromagnetic interaction with the stator, a first driver supplying a first driving current to the first winding set, a second driver supplying a second driving current to the second winding set, a 9-axis sensor measuring values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism, and measurement in a 9-axis sensor There is provided an in-wheel type dual motor device including a controller that independently controls operations of a first driver and a second driver in response to a three-dimensional movement.

In addition, in the present invention, the first winding set and the second winding set are characterized in that they have different amounts of winding.

Further, in the present invention, the first winding set and the second winding set are each independently wound on one coil shaft while having different winding amounts.

In addition, the control unit included in the present invention is characterized in that it selectively drives at least one or more of the first driver and the second driver according to the inclination angle measured by the 9-axis sensor.

An in-wheel type dual motor device according to an embodiment of the present invention has a structure in which a plurality of winding sets are mounted on one motor applied to one axis. Therefore, by selectively driving the plurality of winding sets according to load conditions, it is possible to secure operation stability and improve driving performance.

That is, if the characteristics of the two winding sets are differently designed, divided into torque characteristics and speed characteristics, and complexly controlled according to driving conditions, overall motion characteristics can be improved. In addition, since the in-wheel motor has a structure in which two winding sets are contained in a single housing, it can be configured in a simple form without additional structures such as gears or pulleys.

1 is a block diagram of an in-wheel type dual motor device according to an embodiment of the present invention
2 is a block diagram of an in-wheel type dual motor device according to another embodiment of the present invention

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings in order to describe in detail enough for those skilled in the art to easily implement the technical idea of the present invention.

1 is a configuration diagram of an in-wheel type dual motor device 1 according to an embodiment of the present invention.

The in-wheel type dual motor device 1 according to an embodiment of the present invention includes only a simple configuration for clearly explaining the technical idea to be proposed.

Referring to FIG. 1 , the in-wheel type dual motor device 1 includes a motor 100, a first driver 210, a second driver 220, a power supply unit 300, and a control unit 400.

The motor 100 includes a stator and a motor rotor 160, and in this embodiment, the stator includes a first winding set 110 and a second winding set 120.

The main operations of the in-wheel type dual motor device 1 configured as described above are as follows.

A BLDC motor may be used as the motor 100. The motor 100 includes a stator in which a coil is wound around a cylindrical coil shaft, and a rotor 160 that rotates by interaction with electromagnetic force generated when current flows through the coil of the stator. A permanent magnet is disposed in the rotor 160, and the permanent magnet obtains rotational force by interaction with the electromagnetic force generated from the stator.

The stator of the in-wheel type dual motor device 1 includes a first winding set 110 and a second winding set 120, and the first winding set 110 and the second winding set 120 are different from each other. It is preferable to have a winding amount. At this time, the first winding set 110 and the second winding set 120 may be configured to be independently wound on one coil shaft while having different winding amounts.

The first driver 210 supplies the first driving current I_DRV1 to the first winding set 110, and the second driver 220 supplies the second driving current I_DRV1 to the second winding set 120, respectively.

Although not shown in the drawing, the in-wheel type dual motor device 1 may further include a 9-axis sensor. A 9-axis sensor is defined as a sensor that measures values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism.

The 9-axis sensor is referred to as a 9-axis sensor because values of a total of 9 axes are measured with 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism, and a temperature sensor may be additionally provided to correct the temperature value. The 9-axis sensor can sense the movement direction and tilt by detecting the three-dimensional movement of the in-wheel type dual motor device 1 .

The controller 400 independently controls the operation of the first driver 210 and the second driver 220 in response to the 3D motion measured by the 9-axis sensor.

That is, the controller 400 selectively drives at least one of the first driver 210 and the second driver 220 according to the inclination angle measured by the 9-axis sensor, thereby enabling efficient driving according to the inclination angle.

The power supply unit 300 may be defined as a secondary battery and may include a rechargeable lithium ion battery or a pseudo capacitor.

The power supply unit 300 supplies driving power to the first driver 210 and the second driver 220 under the control of the control unit 400 .

For reference, the power supply 300 may be composed of a plurality of pseudo capacitors. The pseudo capacitor uses a two-dimensional oxidation-reduction reaction at the electrode, so it has a higher capacitance than a general capacitor and has a relatively long lifespan.

The in-wheel type dual motor device 1 may selectively operate the first winding set 110 and the second winding set 120 through the first driver 210 and the second driver 220 in consideration of the inclination (inclination angle).

Since the first winding set 110 and the second winding set 120 are configured to produce different outputs, they are divided into a winding set capable of providing a lot of torque and a winding set capable of providing a high speed, and then selectively and effectively provide driving force according to the necessary situation.

In addition, the control unit 400 receives feedback of temperature values and driving conditions from the first winding set 110 and the second winding set 120, and if overheating or an error occurs, the controller 400 temporarily stops the operation of the corresponding winding set, and drives only the normally operating winding set to enable safe driving. At this time, when the overheated winding set reaches the normal temperature, the control unit 400 returns the winding set that has reached the normal temperature to normal operation.

In addition, the control unit 400 comprehensively considers conditions such as the weight of the occupant of the in-wheel type dual motor device 1, the inclination angle of the road, the remaining battery, etc. The first winding set 110 and the second winding set 120 can be selected and driven.

In addition, when a torque sensor or a load sensor is further provided, the controller 400 may select and drive the first winding set 110 and the second winding set 120 according to the measured values of the torque sensor or the load sensor.

Meanwhile, the motor 100 includes an encoder, and the encoder performs a function of checking the number of revolutions of the motor, the direction of rotation of the motor, the number of revolutions, and the initial position of the motor shaft. The encoder may be connected to the rotation shaft of the motor 100 .

For reference, a method for verifying the current position of the rotor of the motor 100 generally counts the current position based on the Z-phase of the encoder. Therefore, the point at which phase Z output appears from the encoder is called the initial position of the rotor, and from here, the 360-degree position of the rotor is calculated in relation to the resolution (number of pulses per rotation) of the encoder phases A and B. Therefore, if the resolution of the encoder is high, more precise data can be obtained in detecting the position of the rotor.

Forward/reverse rotation can be determined by the fact that phase A and B of the encoder have a phase difference of 90 degrees, and during forward rotation, phase A of the encoder is ahead by 90 degrees, and during reverse rotation, phase B is ahead by 90 degrees.

If the Z-phase pulse (origin signal) of the encoder clears or loads the count whenever the Z-phase pulse occurs, the position counter is always cleared/loaded at a constant position whenever the rotor rotates once. Therefore, when the position of the rotor is determined by the position of the encoder, no cumulative error occurs and a count within the precision of the encoder occurs.

That is, the control unit 400 checks the current state of the motor through signals (PULSE1 (A, B, Z) and PULSE2 (A, B, Z)) fed back from the motor 100, and then controls the driver. Outputs control signals (DRV_CTRL1 and DRV_CTRL2).

2 is a block diagram of an in-wheel type dual motor device 2 according to another embodiment of the present invention.

The in-wheel type dual motor device 2 according to another embodiment of the present embodiment includes only a simple configuration for clearly explaining the technical idea to be proposed.

Referring to FIG. 2 , the in-wheel type dual motor device 2 includes a motor 100, a first driver 210, a second driver 220, a power supply unit 300, a control unit 400, and a current sensor 500.

The motor 100 includes a stator and a motor rotor 160, and in this embodiment, the stator includes a first winding set 110 and a second winding set 120.

The main operations of the in-wheel type dual motor device 2 configured as described above are as follows.

A BLDC motor may be used as the motor 100. The motor 100 includes a stator in which a coil is wound around a cylindrical coil shaft, and a rotor 160 that rotates by interaction with electromagnetic force generated when current flows through the coil of the stator. A permanent magnet is disposed in the rotor 160, and the permanent magnet obtains rotational force by interaction with the electromagnetic force generated from the stator.

The stator of the in-wheel type dual motor device 1 includes a first winding set 110 and a second winding set 120, and the first winding set 110 and the second winding set 120 are different from each other. It is preferable to have a winding amount. At this time, the first winding set 110 and the second winding set 120 may be configured to be independently wound on one coil shaft while having different winding amounts.

The first driver 210 supplies the first driving current I_DRV1 to the first winding set 110, and the second driver 220 supplies the second driving current I_DRV1 to the second winding set 120, respectively.

The current sensor 500 may be composed of a current transformer (CT). When the driving currents (I_DRV1, I_DRV2) are directly measured, measurement time may be restricted due to a too high current value, and device damage or injury may occur due to the high current value. Therefore, the current value is reduced using a current transformer for safely measuring high current to stably measure the amount of change in the driving current (I_DRV1, I_DRV2).

That is, the current transformer outputs the sensing currents I_1 and I_2 corresponding to the driving currents I_DRV1 and I_DRV2 in a non-contact manner using inductance. For reference, the current transformer may be composed of a split core or a solid core.

For reference, the current sensor 500 may be configured to be connected between the power supply unit 300 and the drivers 210 and 220 to sense a current change amount and output sensing currents I_1 and I_2. When the current sensor 500 is connected between the power supply 300 and the drivers 210 and 220, noise inflow is reduced and the waveforms of the sensing currents I_1 and I_2 can be output clearly.

Although not shown in the drawing, the in-wheel type dual motor device 1 may further include a 9-axis sensor. A 9-axis sensor is defined as a sensor that measures values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism.

The 9-axis sensor is referred to as a 9-axis sensor because values of a total of 9 axes are measured with 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism, and a temperature sensor may be additionally provided to correct the temperature value. The 9-axis sensor can sense the movement direction and tilt by detecting the three-dimensional movement of the in-wheel type dual motor device 1 .

The controller 400 independently controls the operation of the first driver 210 and the second driver 220 in response to the 3D motion measured by the 9-axis sensor.

That is, the controller 400 selectively drives at least one of the first driver 210 and the second driver 220 according to the inclination angle measured by the 9-axis sensor, thereby enabling efficient driving according to the inclination angle.

The power supply unit 300 may be defined as a secondary battery and may include a rechargeable lithium ion battery or a pseudo capacitor.

The power supply unit 300 supplies driving power to the first driver 210 and the second driver 220 under the control of the control unit 400 .

For reference, the power supply 300 may be composed of a plurality of pseudo capacitors. The pseudo capacitor uses a two-dimensional oxidation-reduction reaction at the electrode, so it has a higher capacitance than a general capacitor and has a relatively long lifespan.

The in-wheel type dual motor device 1 may selectively operate the first winding set 110 and the second winding set 120 through the first driver 210 and the second driver 220 in consideration of the inclination (inclination angle).

Since the first winding set 110 and the second winding set 120 are configured to produce different outputs, they are divided into a winding set capable of providing a lot of torque and a winding set capable of providing a high speed, and then selectively and effectively provide driving force according to the necessary situation.

In addition, the control unit 400 receives feedback of temperature values and driving conditions from the first winding set 110 and the second winding set 120, and if overheating or an error occurs, the controller 400 temporarily stops the operation of the corresponding winding set, and drives only the normally operating winding set to enable safe driving. At this time, when the overheated winding set reaches the normal temperature, the control unit 400 returns the winding set that has reached the normal temperature to normal operation.

In addition, the control unit 400 comprehensively considers conditions such as the weight of the occupant of the in-wheel type dual motor device 1, the inclination angle of the road, the remaining battery, etc. The first winding set 110 and the second winding set 120 can be selected and driven.

In addition, when a torque sensor or a load sensor is further provided, the controller 400 may select and drive the first winding set 110 and the second winding set 120 according to the measured values of the torque sensor or the load sensor.

That is, since the control unit 400 can detect the respective torques of the first winding set 110 and the second winding set 120 based on the magnitudes of the sensing currents I_1 and I_2, the driving operation of the first driver 210 and the second driver 220 is controlled after distinguishing between a case in which a large amount of torque is required and a case in which a large amount of torque is required. Since the driving currents I_DRV1 and I_DRV2 are proportional to the torque, the torque can be detected through the sensing currents I_1 and I_2 reflecting the magnitudes of the driving currents I_DRV1 and I_DRV2.

Meanwhile, the control unit 400 may be configured to selectively charge at least one of a plurality of pseudocapacitors according to the level of charging power when charging the power supply unit 300 . The charging method is described in detail as follows.

Assume that three pseudo capacitors are disposed, that is, a first pseudo capacitor, a second pseudo capacitor, and a third pseudo capacitor are disposed. At this time, it is assumed that the charging capacity of the first pseudo capacitor is the highest, the charging capacity of the second pseudo capacitor is smaller than that of the first pseudo capacitor, and the charging capacity of the third pseudo capacitor is smaller than that of the second pseudo capacitor.

The controller 400 detects the charged amounts of the first pseudo capacitor, the second pseudo capacitor, and the third pseudo capacitor, and then supplies driving power in order of highest charged amounts.

For example, when the charge amount of the first pseudo capacitor is 60%, the charge amount of the second pseudo capacitor is 70%, and the charge amount of the third pseudo capacitor is 80%,

The power of the third pseudo capacitor is supplied first, and when the charge amount reaches 40%, the power supply of the third pseudo capacitor is cut off and the power of the second pseudo capacitor is supplied. In addition, when the charge amount of the second pseudo capacitor reaches 40%, power supply to the second pseudo capacitor is cut off and power is supplied to the first pseudo capacitor.

In addition, when the charge amounts of the first to third pseudo capacitors are all less than 40%, the controller 150 connects the first to third pseudo capacitors in parallel to supply driving power.

A rotating shaft is connected to the motor 100 of the in-wheel type dual motor device 2 and a plurality of bearings are connected to the rotating shaft. That is, while supporting the load of the bearing rotation shaft, the frictional force when the rotation shaft rotates is reduced.

The motor 100 may be controlled through an open-loop control method or a closed-loop control method.

In addition, the torque control of the motor 100 is performed by controlling the current flowing into the motor 100, and the control of the speed, position, and direction of rotation of the motor is finally performed by controlling the power, that is, the current flowing into the motor 100.

The motor 100 includes an encoder, and the encoder performs a function of checking the number of revolutions of the motor, the direction of rotation of the motor, the number of revolutions, and the initial position of the motor shaft. The encoder may be connected to the rotation shaft of the motor 100 .

For reference, a method for verifying the current position of the rotor of the motor 100 generally counts the current position based on the Z-phase of the encoder. Therefore, the point at which phase Z output appears from the encoder is called the initial position of the rotor, and from here, the 360-degree position of the rotor is calculated in relation to the resolution (number of pulses per rotation) of the encoder phases A and B. Therefore, if the resolution of the encoder is high, more precise data can be obtained in detecting the position of the rotor.

Forward/reverse rotation can be determined by the fact that phase A and B of the encoder have a phase difference of 90 degrees, and during forward rotation, phase A of the encoder is ahead by 90 degrees, and during reverse rotation, phase B is ahead by 90 degrees.

If the Z-phase pulse (origin signal) of the encoder clears or loads the count whenever the Z-phase pulse occurs, the position counter is always cleared/loaded at a constant position whenever the rotor rotates once. Therefore, when the position of the rotor is determined by the position of the encoder, no cumulative error occurs and a count within the precision of the encoder occurs.

That is, the control unit 400 checks the current state of the motor through signals (PULSE1 (A, B, Z) and PULSE2 (A, B, Z)) fed back from the motor 100, and then controls the driver. Outputs control signals (DRV_CTRL1 and DRV_CTRL2).

The controller 400 may control the rotational speed and direction of the motor 100 by adjusting the driving currents I_DRV1 and I_DRV2 supplied to the motor 100 using the driving control signals DRV_CTRL1 and DRV_CTRL2. The control unit 400 maintains the rotational speed of the motor 100 constant when performing an operation of detecting the wear amount of the bearing.

In addition, the control unit 400 receives feedback of the drive currents I_DRV1 and I_DRV2 supplied to the motor 100 and calculates the wear amount of the bearing in real time based on the amount of change in the drive currents I_DRV1 and I_DRV2 over time.

The control unit 400 may be configured to directly receive feedback of the driving currents I_DRV1 and I_DRV2 supplied to the motor 100 and sense the amount of change in the driving currents I_DRV1 and I_DRV2. .

That is, the current sensor 500 may be composed of a current transformer (CT). When directly measuring the drive currents (I_DRV1, I_DRV2), measurement time may be restricted due to a too high current value, and damage or injury may occur to the device due to the high current value. Therefore, the current value is reduced using a current transformer for safely measuring high current to stably measure the amount of change in the driving current (I_DRV1, I_DRV2).

The current transformer uses inductance to output sensing currents I_1 and I_2 corresponding to driving currents I_DRV1 and I_DRV2 in a non-contact manner. For reference, the current transformer may be composed of a split core or a solid core.

For reference, the current sensor 500 may be configured to be connected between the power supply unit 300 and the driver to sense a current variation and output sensing currents I_1 and I_2. When the current sensor 500 is connected between the power supply 300 and the driver, noise inflow is reduced and the waveforms of the sensing currents I_1 and I_2 can be clearly output.

In this embodiment, the control unit 400 is configured to determine the amount of change in the driving currents I_DRV1 and I_DRV2 through the sensing currents I_1 and I_2 provided from the current sensor 500 .

First of all, in the case of bearings in which wear has not progressed the most, the values of the sensing currents (I_1, I_2) are measured to be the lowest. In addition, changes in amplitude of the waveforms of the sensing currents I_1 and I_2 are measured very uniformly.

Next, in the case of bearings in which relatively more and more wear has occurred, the values of the sensing currents I_1 and I_2 uniformly increase as the amount of wear increases.

That is, assuming that the wear of the bearing progresses very uniformly, as the wear progresses, the values of the sensing currents I_1 and I_2 generally increase while the change in the amplitude of the waveform of the sensing currents I_1 and I_2 is almost constant.

The control unit 400 stores or sets a wear threshold of the bearing, and the wear threshold is defined as a reference wear amount REF1. Therefore, the control unit 400 may periodically inform the replacement timing of the bearing by calculating the progress speed of the wear amount of the bearing.

That is, since the control unit 400 can calculate the point at which the wear threshold is reached in consideration of the total use time of the bearing and the progress rate of the amount of wear, the expected replacement time can be calculated based on the average use time (daily, weekly, monthly) whenever the total used time is changed.

For reference, when the wear limit is reached, any one of daily maximum usage time, weekly maximum usage time, and monthly maximum usage time may be selected and the replacement time may be calculated based on the maximum usage time.

The control unit 400 may be configured to receive feedback of the driving current I_DRV or the sensing current I_1 based on the origin signal (Z-phase pulse) transmitted from the encoder of the motor 100. For reference, the origin signal (Z-phase pulse) transmitted from the encoder is a signal that pulses every time the motor 300 rotates.

In addition, when setting the maximum use time desired by the user, the control unit 400 selectively drives either one of the first winding set 110 and the second winding set 120 in consideration of the wear limit of the bearing to limit the maximum output, thereby automatically adjusting the drive to the use time desired by the user.

An in-wheel type dual motor device according to an embodiment of the present invention has a structure in which a plurality of winding sets are mounted on one motor applied to one axis. Therefore, by selectively driving the plurality of winding sets according to load conditions, it is possible to secure operation stability and improve driving performance.

That is, if the characteristics of the two winding sets are differently designed, divided into torque characteristics and speed characteristics, and complexly controlled according to driving conditions, overall motion characteristics can be improved. In addition, since the in-wheel motor has a structure in which two winding sets are contained in a single housing, it can be configured in a simple form without additional structures such as gears or pulleys.

As such, those skilled in the art to which the present invention pertains will be able to understand that the present invention may be embodied in other specific forms without changing its technical spirit or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention. It should be construed.

100: motor
110: first winding set
120: second winding set
160: rotor
210: first driver
220: second driver
300: power supply
400: control unit
500: current sensor

Claims (4)

a stator having a first winding set and a second winding set;
a rotor rotating by electromagnetic interaction with the stator;
a first driver supplying a first driving current to the first winding set;
a second driver supplying a second driving current to the second winding set;
A 9-axis sensor that measures values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism;
a controller that independently controls operations of the first driver and the second driver in response to the 3-dimensional motion measured by the 9-axis sensor; and
A current sensor for measuring the amount of change in the first and second driving currents;
The first winding set and the second winding set are each independently wound on one coil shaft while having different winding amounts,
The control unit controls the rotational speed of the rotor to be constant, receives feedback from the sensing current sensed by the current sensor, indirectly senses the amount of change in the first and second drive currents, and calculates the amount of wear of the bearing in real time based on the amount of change in the first and second drive currents. In-wheel type dual motor device.
delete delete According to claim 1,
The in-wheel type dual motor device, characterized in that the control unit selectively drives at least one or more of the first driver and the second driver according to the inclination angle measured by the 9-axis sensor.