KR20220058047A - In-wheel type dual motor device for personal mobility - Google Patents

Abstract

An in-wheel type dual motor device comprises: a stator having a first winding set and a second winding set; a rotor that rotates 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 terrestrial magnetism; and a control unit that independently controls operations of the first driver and the second driver in response to three-dimensional motion measured by the 9-axis sensor.

Description

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.

A means of transportation using an internal combustion engine using fossil fuels appeared at the end of the 19th century and has continued to develop while expanding the market by establishing itself as a major trend in the transportation market through World Wars I and II.

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

Accordingly, in Korea, the development and distribution of scooters, motorcycles, automobiles, etc. using electric motors is expanding due to social interest in environmental protection and policy support for transportation means to replace internal combustion engines.

In Korea, since more than 60% of the country is mountainous, there are many sloping roads regardless of urban and rural areas.

In the case of the initial model, as it is a motor suitable for flat land, and it is necessary to install a large-capacity motor when driving on an incline frequently, there is a problem of a decrease in battery usage efficiency and an increase in price.

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

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

When two motors are used for the front and rear wheel motors that are linked according to the driving conditions, appropriate torque distribution and rotational speed are controlled to the front and rear wheels according to the load grip (resistance between the tire and the road surface) and the movement of the center of gravity there is a need to

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

When installing an electric motor 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.

US 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 shaft.

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, and a first winding set A first driver supplying one driving current, a second driver supplying a second driving current to the second winding set, and a 9-axis sensor measuring values of 9 axes including 3 axes of acceleration, 3 axes of inertia, and 3 axes of geomagnetism And, an in-wheel type dual motor device including a control unit for independently controlling operations of a first driver and a second driver in response to a three-dimensional movement measured by a 9-axis sensor is provided.

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

In addition, 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 of the first driver and the second driver according to the inclination angle measured by the 9-axis sensor.

The in-wheel type dual motor device according to an embodiment of the present invention is formed in a structure in which a plurality of winding sets are mounted on one motor applied to one shaft. Accordingly, by selectively driving a plurality of winding sets according to a load situation, operation stability can be secured and driving performance can be improved.

That is, by designing the characteristics of the two winding sets differently, dividing them into torque characteristics and speed characteristics, and controlling them in combination according to driving conditions, the 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, an embodiment of the present invention will be described with reference to the accompanying drawings in order to describe in detail enough that a person of ordinary skill in the art can easily implement the technical idea of the present invention.

1 is a block 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 operation of the in-wheel type dual motor device 1 configured as described above is as follows.

The motor 100 may be a BLDC motor, and 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 a current flows in the coil of the stator. ) is included. A permanent magnet is disposed in the rotor 160 , and the permanent magnet obtains rotational force by interaction with electromagnetic force generated in 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, wherein the first winding set 110 and the second winding set 120 have different winding amounts. It is preferable to be configured to have a. In this case, 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 a first driving current I_DRV1 to the first winding set 110 , and the second driver 220 applies a second driving current I_DRV1 to the second winding set 120 , respectively. supply

Although not shown in the drawings, 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 the 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 compensate for the temperature value. The 9-axis sensor may detect a three-dimensional movement of the in-wheel type dual motor device 1 to detect a movement direction, an inclination, and the like.

The controller 400 independently controls the operations of the first driver 210 and the second driver 220 in response to the three-dimensional movement measured by the 9-axis sensor.

That is, the control unit 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, respectively, under the control of the controller 400 .

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

The in-wheel type dual motor device 1 selectively operates 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) can do.

Since the first winding set 110 and the second winding set 120 are configured to output different outputs, it is divided into a winding set capable of providing a large amount of torque and a winding set capable of providing a high speed. A driving force can be effectively provided selectively according to a necessary situation.

In addition, the control unit 400 receives the feedback of the temperature value and the driving state from the first winding set 110 and the second winding set 120 , and then temporarily stops the operation of the winding set when overheating or an error occurs. After this, safe driving is possible by driving only the normally operating winding set. 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 selects the first winding set 110 and the second winding set 120 by comprehensively considering the weight of the occupant of the in-wheel type dual motor device 1, the inclination angle of the road, the remaining battery, and the like. can be driven by

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

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

For reference, the method of 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 the Z-phase output appears from the encoder is called the initial position of the rotor, and the 360-degree position of the rotor is calculated from here in relation to the resolution (number of pulses per rotation) of the A and B phases of the encoder. Therefore, if the resolution of the encoder is high, more precise data can be obtained in detecting the position of the rotor.

What can determine the forward/reverse rotation is that the phase A and phase B of the encoder have a phase difference of 90 degrees from each other, and during forward rotation, phase A of the encoder leads 90° in phase, and in reverse rotation, phase B leads by 90°. If you read the state of A phase at the moment it changes from Low to High, you can know the forward/reverse rotation with the value at that time.

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

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

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 . is comprised of

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 operation of the in-wheel type dual motor device 2 configured as described above is as follows.

The motor 100 may be a BLDC motor, and 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 a current flows in the coil of the stator. ) is included. A permanent magnet is disposed in the rotor 160 , and the permanent magnet obtains rotational force by interaction with electromagnetic force generated in 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, wherein the first winding set 110 and the second winding set 120 have different winding amounts. It is preferable to be configured to have a. In this case, 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 a first driving current I_DRV1 to the first winding set 110 , and the second driver 220 applies a second driving current I_DRV1 to the second winding set 120 , respectively. supply

The current sensor 500 may be composed of a current transformer (CT). When the driving currents I_DRV1 and I_DRV2 are directly measured, the measurement time may be limited due to an excessively high current value, and a high current value may cause equipment damage or injury. Therefore, by using a current transformer for safely measuring high current, the current value is decreased to stably measure the amount of change in the driving currents (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 the inductance. For reference, the current transformer may consist 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 detect a change in current and output sensing currents I_1 and I_2. When the current sensor 500 is connected between the power supply unit 300 and the drivers 210 and 220 , noise inflow is reduced, so that the waveforms of the sensing currents I_1 and I_2 can be clearly output.

Although not shown in the drawings, 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 the 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 compensate for the temperature value. The 9-axis sensor may detect a three-dimensional movement of the in-wheel type dual motor device 1 to detect a movement direction, an inclination, and the like.

The controller 400 independently controls the operations of the first driver 210 and the second driver 220 in response to the three-dimensional movement measured by the 9-axis sensor.

That is, the control unit 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, respectively, under the control of the controller 400 .

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

The in-wheel type dual motor device 1 selectively operates 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) can do.

Since the first winding set 110 and the second winding set 120 are configured to output different outputs, it is divided into a winding set capable of providing a large amount of torque and a winding set capable of providing a high speed. A driving force can be effectively provided selectively according to a necessary situation.

In addition, the control unit 400 receives the feedback of the temperature value and the driving state from the first winding set 110 and the second winding set 120 , and then temporarily stops the operation of the winding set when overheating or an error occurs. After this, safe driving is possible by driving only the normally operating winding set. 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 selects the first winding set 110 and the second winding set 120 by comprehensively considering the weight of the occupant of the in-wheel type dual motor device 1, the inclination angle of the road, the remaining battery, and the like. can be driven by

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

That is, 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, so that when a large amount of torque is not required, , control the driving operation of the first driver 210 and the second driver 220 after classifying 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 magnitude of the driving currents I_DRV1 and I_DRV2.

Meanwhile, the control unit 400 may be configured to selectively charge at least one of the plurality of pseudo-capacitors according to the amount of charging power when the power supply unit 300 is charged. The charging method will be described in detail as follows.

It is assumed that when three pseudo capacitors are disposed, that is, the first pseudo capacitor, the second pseudo capacitor and the third pseudo capacitor are disposed. In this case, it is assumed that the charging capacity of the first pseudo capacitor is the largest, 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 control unit 400 detects the charge amounts of the first pseudo capacitor, the second pseudo capacitor, and the third pseudo capacitor, and then supplies driving power in the order of the highest charge 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 first supplied, 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%, the power supply of the second pseudo capacitor is cut off and the power of the first pseudo capacitor is supplied.

Also, when the charging amounts of the first to third pseudo capacitors are all 40% or less, 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, the frictional force when the rotating shaft rotates is reduced while supporting the load of the bearing rotating shaft.

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

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

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

For reference, the method of 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 the Z-phase output appears from the encoder is called the initial position of the rotor, and the 360-degree position of the rotor is calculated from here in relation to the resolution (number of pulses per rotation) of the A and B phases of the encoder. Therefore, if the resolution of the encoder is high, more precise data can be obtained in detecting the position of the rotor.

What can determine the forward/reverse rotation is that the phase A and phase B of the encoder have a phase difference of 90 degrees from each other, and during forward rotation, phase A of the encoder leads 90° in phase, and in reverse rotation, phase B leads by 90°. If you read the state of A phase at the moment it changes from Low to High, you can know the forward/reverse rotation with the value at that time.

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

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

The controller 400 may control the rotation 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 a constant rotational speed of the motor 100 when performing an operation for detecting the wear amount of the bearing.

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

The control unit 400 may be configured to directly receive feedback from the driving currents I_DRV1 and I_DRV2 supplied to the motor 100 to sense the amount of change in the driving currents I_DRV1 and I_DRV2. The sensing currents I_1 and I_2 sensed from the current sensor 500 are fed back to indirectly sense changes in the driving currents I_DRV1 and I_DRV2.

That is, the current sensor 500 may be composed of a current transformer (CT). When the driving currents I_DRV1 and I_DRV2 are directly measured, the measurement time may be limited due to too high current value, and high Device damage or personal injury may occur depending on the current value. Therefore, by using a current transformer for safely measuring high current, the current value is decreased to stably measure the amount of change in the driving currents (I_DRV1, I_DRV2).

The current transformer outputs sensing currents I_1 and I_2 corresponding to the driving currents I_DRV1 and I_DRV2 in a non-contact manner using the inductance. For reference, the current transformer may consist 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 change in current and output sensing currents I_1 and I_2. When the current sensor 500 is connected between the power supply unit 300 and the driver, noise inflow is reduced, so that the waveforms of the sensing currents I_1 and I_2 can be clearly output.

In the present embodiment, the control unit 400 is configured to detect changes 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, in the case of the bearing that wears the least, the sensing currents (I_1, I_2) have the lowest values. In addition, the change in the amplitude of the sensing current (I_1, I_2) waveform is measured very uniformly.

Next, in the case of bearings that have been relatively worn more and more, the values of the sensing currents I_1 and I_2 also increase uniformly as the amount of wear increases.

That is, if it is assumed that the wear of the bearing proceeds very uniformly, as the wear progresses, the change in the amplitude of the waveform of the sensing current (I_1, I_2) is almost constant, and the value of the sensing current (I_1, I_2) increases as a whole. .

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

That is, the control unit 400 can calculate the time at which the wear limit is reached in consideration of the total use time of the bearing and the progress rate of the amount of wear, so whenever the total use time is changed, the average use time (daily, weekly, Monthly), the expected replacement time can be calculated.

For reference, when the wear threshold is reached, any one of daily maximum use time, weekly maximum use time, and monthly maximum use time is selected among the total use time, and the replacement time may be calculated based on the maximum use time. will be.

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 is pulsed every one rotation of the motor 300 .

In addition, when the user sets the desired maximum use time, the control unit 400 selectively drives any one of the first winding set 110 and the second winding set 120 in consideration of the wear limit of the bearing to achieve the maximum output. It can be automatically adjusted so that it can be operated up to the user's desired use time by limiting the

The in-wheel type dual motor device according to an embodiment of the present invention is formed in a structure in which a plurality of winding sets are mounted on one motor applied to one shaft. Accordingly, by selectively driving a plurality of winding sets according to a load situation, operation stability can be secured and driving performance can be improved.

That is, by designing the characteristics of the two winding sets differently, dividing them into torque characteristics and speed characteristics, and controlling them in combination according to driving conditions, the 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 the technical spirit or essential characteristics thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

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; and
a control unit for independently controlling the operations of the first driver and the second driver in response to the three-dimensional movement measured by the 9-axis sensor;
An in-wheel type dual motor device comprising a.
According to claim 1,
The in-wheel type dual motor device, characterized in that the first winding set and the second winding set have different winding amounts.
According to claim 1,
The in-wheel type dual motor device, characterized in that the first winding set and the second winding set are each independently wound on one coil shaft while having different winding amounts.
According to claim 1,
The controller selectively drives at least one of the first driver and the second driver according to the inclination angle measured by the 9-axis sensor.

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