Drive system for low-speed electric vehicles, and low-speed electric vehicles

Abstract

To provide a driving device of a low-speed electric vehicle, which can suppress wiring from being complicated and broken and improve performance in making the low-speed electric vehicle continuously run.SOLUTION: A driving device, which drives a low-speed electric vehicle whose maximum speed is a predetermined low speed or below, is equipped with: a motor (60) comprising a rotor (63) and two stator windings (61 and 62); two motor drivers (71 and 72) that respectively change electric power to be supplied to the two stator windings; and a controller (75) that controls the two motor drivers. The motor, the two motor drivers and the controller are integrated into one module (50). The controller can execute a plurality of control modes of controlling the motor.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a low-speed electric vehicle whose maximum speed is below a predetermined low speed (for example, 20 [km / h], 30 [km / h], etc.). , and its drive unit

Background Art

[0002] Conventionally, there has been an electric kick scooter that transports people and luggage by providing a main battery and an auxiliary battery, sending the power of the two batteries to a controller by a circuit, and switching or controlling the power of the two batteries by the controller and then sending it to a motor (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in low-speed electric vehicles such as electric kick scooters, in general, due to cost reduction, they often have a simple structure, and the motor, motor driver, and controller are separate bodies. For this reason, there is a risk that the wiring becomes complicated or the wiring is disconnected. Also, in low-speed electric vehicles, in many cases, when the motor winding is disconnected or the motor driver fails, no measures other than stopping the running can be taken. Furthermore, in low-speed electric vehicles, it is difficult to mount a large-capacity battery, so there is a problem that the continuous driving distance is short.

[0005] The present invention has been made to solve the above problems, and its main object is to suppress complication and disconnection of wiring in a drive device of a low-speed electric vehicle and improve the running continuity of the low-speed electric vehicle. , and its

Means for Solving the Problems

[0006] The first means to solve the above problem is, A drive unit for driving a low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module (50). The output shaft (65) of the motor is connected to the drive wheel (14) of the low-speed electric vehicle via a sprocket (15) and a chain (16). The motor is attached to a bracket (18) that supports the drive wheel of the low-speed electric vehicle. The controller is capable of executing multiple control modes for controlling the motor.

[0007] According to the above configuration, the drive system drives a low-speed electric vehicle whose maximum speed is a predetermined low speed (e.g., 20 km / h, 30 km / h, etc.) or less. The motor comprises a rotor and two stator windings (motor windings). Two motor drivers each change the power supplied to the two stator windings. The controller controls the two motor drivers. Therefore, even if one of the two stator windings is broken, the motor can be rotated by supplying power to the other stator winding. Also, even if one of the two motor drivers fails, the motor can be rotated by changing the power supplied to the corresponding stator winding by the other motor driver. Thus, in a drive system for a low-speed electric vehicle, the ability to continue driving the low-speed electric vehicle in the event of a stator winding break or a motor driver failure can be improved.

[0008] The motor, the two motor drivers, and the controller are integrated into a single module. This reduces the complexity of the wiring connecting them and prevents disconnections in the connecting wires. In particular, when the motor has two stator windings and the drive unit has two motor drivers and a controller, the wiring connecting them becomes more complex and prone to disconnections. Therefore, integrating them into a single module further enhances the above-mentioned benefits.

[0009] Furthermore, the controller is capable of executing multiple control modes for controlling the motor. Therefore, the control mode can be switched according to the state of the low-speed electric vehicle, thereby suppressing power consumption and improving power utilization efficiency. Consequently, even low-speed electric vehicles that have difficulty being equipped with large-capacity batteries can have their continuous operation improved.

[0010] In the second configuration, a circuit board (76) on which the motor driver and controller are mounted is attached to one end (60a) of the motor in the longitudinal direction, a connector (77) for connecting wiring (79) to the motor driver and controller is attached to the circuit board, the motor and the connector are arranged in parallel, and the longitudinal direction of the motor and the longitudinal direction of the connector coincide.

[0011] According to the above configuration, a circuit board on which the motor driver and the controller are mounted is attached to one end of the motor in the longitudinal direction. Therefore, the motor driver and the controller can be arranged together at one end of the motor in the longitudinal direction. Connectors for connecting wiring to the motor driver and the controller are attached to the circuit board. Therefore, wiring can be connected to the motor driver and the controller via the connectors and the circuit board. Furthermore, the motor and the connector are arranged in parallel, and the longitudinal direction of the motor and the longitudinal direction of the connector coincide. Therefore, the space required for arranging the motor and the connector can be reduced. In addition, by aligning the longitudinal direction of the motor and the longitudinal direction of the connector with the vehicle width direction of the low-speed electric vehicle, the vehicle width of the low-speed electric vehicle can be reduced.

[0012] In the third configuration, the output shaft of the motor is connected to the wheels of the low-speed electric vehicle via a power transmission device. With this configuration, power can be transmitted from the output shaft of the motor to the wheels of the low-speed electric vehicle via the power transmission device.

[0013] In the fourth method, the controller controls the corresponding motor driver to supply power to the other stator winding if one of the two stator windings breaks, thereby continuing to drive the motor. With this configuration, even if one of the two stator windings breaks, the motor can continue to drive, and the low-speed electric vehicle can continue to run. Therefore, it is possible to avoid a situation where the low-speed electric vehicle has to be pushed to move.

[0014] In the fifth method, if one of the two motor drivers fails, the controller controls the other motor driver to supply power to the corresponding stator winding, thereby continuing to drive the motor. With this configuration, even if one of the two motor drivers fails, the motor can continue to drive, and the low-speed electric vehicle can continue to run. Therefore, situations where the low-speed electric vehicle must be pushed to move can be avoided.

[0015] In the sixth means, the plurality of control modes include a torque control mode for controlling the torque of the motor, a rotational speed control mode for controlling the rotational speed of the motor by regenerating power using the motor, and a rotational position control mode for controlling the rotational position of the motor. With this configuration, the torque control mode, rotational speed control mode, and rotational position control mode can be switched according to the intentions of the driver of the low-speed electric vehicle, thereby suppressing power consumption or improving the efficiency of power utilization. Furthermore, the controller can serve as both a motor controller for controlling the motor and a vehicle controller for controlling the entire low-speed electric vehicle.

[0016] The seventh means is that the controller executes the torque control mode when the low-speed electric vehicle is accelerating and driving at a constant speed, executes the rotational speed control mode when the low-speed electric vehicle is decelerating, and executes the rotational position control mode when the low-speed electric vehicle is stopped, as described in claim 6.

[0017] According to the above configuration, the controller executes the torque control mode when the low-speed electric vehicle is accelerating and when it is driving at a constant speed, making it easier to drive the low-speed electric vehicle according to the driver's intentions. The controller executes the rotational speed control mode when the low-speed electric vehicle is decelerating, allowing the motor to regenerate power and effectively utilize energy during deceleration. The controller executes the rotational position control mode when the low-speed electric vehicle is stopped, making it easier to stop the low-speed electric vehicle according to the driver's intentions. The eighth method is, A low-speed electric vehicle whose maximum speed is below a predetermined low speed, The aforementioned low-speed electric vehicle is It consists of a body, frame, front wheels, rear wheels, handlebars, battery, and motor module. The motor module is A motor comprising a rotor and two stator windings, Two motor drivers that change the power supplied to the two stator windings, A controller that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module and are fixed to a bracket that rotatably supports the rear wheel of the vehicle body. The output shaft of the motor is connected to the rear wheel via a sprocket and chain. The ninth method is, A low-speed electric vehicle whose maximum speed is below a predetermined low speed, The aforementioned low-speed electric vehicle is It consists of a body, frame, front wheels, rear wheels, handlebars, battery, and motor module. The motor module is A motor comprising a rotor and two stator windings, Two motor drivers that change the power supplied to the two stator windings, A controller that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module and are located between the battery and the rear wheel. The tenth method is, A low-speed electric vehicle whose maximum speed is below a predetermined low speed, The aforementioned low-speed electric vehicle is It consists of a body, frame, front wheels, rear wheels, handlebars, battery, and motor module. The motor module is A motor comprising a rotor and two stator windings, Two motor drivers that change the power supplied to the two stator windings, A controller that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module and are positioned between the front wheel and the rear wheel. The eleventh measure is, A low-speed electric vehicle whose maximum speed is below a predetermined low speed, The aforementioned low-speed electric vehicle is It consists of a body, frame, front wheel, rear wheel, handlebars, battery, motor module, throttle grip, and brake lever. The front wheel is attached to the lower part of the frame, and the handlebars are attached to the upper part of the frame. The aforementioned accelerator grip and brake lever are attached to the handlebars. The motor module is A motor comprising a rotor and two stator windings, Two motor drivers that change the power supplied to the two stator windings, A controller that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module and are located between the battery and the rear wheel. [Brief explanation of the drawing]

[0018] [Figure 1] A perspective view of an electric kick scooter. [Figure 2] Block diagram of the drive unit and surrounding components. [Figure 3] A schematic diagram showing the motor, control board, and connector. [Modes for carrying out the invention]

[0019] The following describes one embodiment of a drive system for an electric kick scooter, with reference to the drawings.

[0020] As shown in Figure 1, the electric kick scooter 10 is equipped with a body 11, frame 12, front wheel 13, rear wheel 14, handlebars 20, battery 40, and motor module 50, etc. The electric kick scooter 10 (low-speed electric vehicle) is a specified small motorized bicycle, with a maximum speed of 20 km / h or less, no driving required for those under 16 years of age, no license required, and wearing a helmet is a recommended practice.

[0021] The vehicle body 11 is formed in a box shape (hollow rectangular parallelepiped). The top of the vehicle body 11 is a deck 11a on which the driver places their feet. A battery 40 is housed inside the vehicle body 11. A frame 12 is connected to the vehicle body 11.

[0022] The frame 12 extends vertically in a rod-like shape. The front wheel 13 is rotatably mounted on the lower part of the frame 12. The handlebars 20 are mounted on the upper part of the frame 12.

[0023] The handlebars 20 are formed in a rod shape that extends in the left-right direction. An accelerator grip 21, a brake lever 26, etc. are attached to the right side of the handlebars 20. The accelerator grip 21 (accelerator operating member) is formed in a cylindrical shape and is rotatable forward and backward. When the driver rotates the accelerator grip 21 backward (towards the driver), the motor module 50 applies driving force to the rear wheels 14. When the driver grips the brake lever 26, the front brake (not shown) applies braking force to the front wheels 13. A brake lever 27, etc. are attached to the left side of the handlebars 20. When the driver grips the brake lever 27, the rear brake (not shown) applies braking force to the rear wheels 14.

[0024] Figure 2 is a block diagram of the drive unit and its peripheral configuration. As shown in the figure, the battery 40 (storage battery) is connected to the motor module 50 and supplies power to the motor module 50. The battery 40 is also charged by power supplied from the motor module 50.

[0025] An accelerator sensor 80 is provided inside the accelerator grip 21. The accelerator sensor 80 (operated amount sensor) includes a torsion member 83, a first strain gauge 81, and a second strain gauge 82, etc. The torsion member 83 (deformation member) is formed in a cylindrical or columnar shape and deforms torsionally in accordance with the amount of rotation (operated amount) of the accelerator grip 21. Specifically, the larger the amount of rotation of the accelerator grip 21, the larger the amount of torsional deformation (strain) of the torsion member 83. The first strain gauge 81 and the second strain gauge 82 are well-known strain gauges that measure the change in electrical resistance due to the deformation of a resistor arranged in a zigzag (multiple folding) shape and convert this into the amount of strain of the torsion member 83 (object under measurement). The first strain gauge 81 and the second strain gauge 82 are attached to the torsion member 83, respectively, and power is supplied to them from the motor module 50. The first strain gauge 81 and the second strain gauge 82 each detect the amount of strain (operated variable correlation value) of the torsion member 83 and convert it into a digital signal, which is then transmitted to the motor module 50.

[0026] The motor module 50 (module) is an integrated electromechanical module that includes a motor 60, a first motor driver 71, a second motor driver 72, and a controller 75, among other components.

[0027] Motor 60 is a three-phase brushless motor equipped with two stator windings. Motor 60 includes a rotor 63, a first stator winding 61, and a second stator winding 62, etc. Permanent magnets (not shown) are attached to the rotor 63. The first stator winding 61 and the second stator winding 62 are wound around the stator (not shown), respectively. The rotor 63 is rotated by supplying current to the first stator winding 61 and the second stator winding 62 according to the rotational position of the rotor 63. Current can be supplied to the first stator winding 61 and the second stator winding 62 independently (individually). When motor 60 is operating normally, current flows to the first stator winding 61 and the second stator winding 62.

[0028] As shown in Figure 3, the output shaft 65 of the motor 60 is fixed (mounted) to the rotor 63. The output shaft 65 is connected to the rear wheel 14 via a sprocket 15 and chain 16, etc. (power transmission device). In this way, the power from the motor 60 is transmitted to the rear wheel 14 (drive wheel), and the electric kick scooter 10 moves. Also, when the electric kick scooter 10 is decelerated, the rotational force of the rear wheel 14 rotates the rotor 63, and the motor 60 performs regenerative power generation. The sprocket 15 and chain 16, etc. also serve as a reduction device that reduces and transmits the rotation of the output shaft 65.

[0029] The first motor driver 71 and the second motor driver 72 are configured as well-known three-phase bridge-type inverter circuits. The first motor driver 71 is connected to the battery 40 and the first stator winding 61, and converts the DC power supplied from the battery 40 into AC power and supplies it to the first stator winding 61. The second motor driver 72 is connected to the battery 40 and the second stator winding 62, and converts the DC power supplied from the battery 40 into AC power and supplies it to the second stator winding 62. In addition, during regenerative power generation of the motor 60, the first motor driver 71 and the second motor driver 72 convert the AC power supplied from the first stator winding 61 and the second stator winding 62 into DC power and supply it to the battery 40. The first motor driver 71 and the second motor driver 72 are controlled by a controller 75, which changes (controls) the power supplied between the battery 40 and the first stator winding 61 and the second stator winding 62, respectively.

[0030] The speed sensor 90 detects the speed v of the electric kick scooter 10. The speed sensor 90 may detect the speed v based on the rotational speed of the front wheel 13 or the rear wheel 14, or it may detect the speed v based on the rotational speed (rotational position) of the motor 60 (rotor 63). The speed sensor 90 converts the detected speed v into a digital signal and transmits it to the motor module 50 (controller 75).

[0031] The controller 75 is mainly composed of a microcomputer equipped with a CPU, ROM, RAM, storage device, and input / output interface. The controller 75 controls the driving state and power generation state of the motor 60 by controlling the first motor driver 71 and the second motor driver 72. The controller 75 controls the first motor driver 71 and the second motor driver 72 based on the detection results of the first strain gauge 81, the second strain gauge 82, and the speed sensor 90. The motor 60, motor drivers 71 and 72, accelerator sensor 80, and controller 75 constitute the drive system for the low-speed electric vehicle.

[0032] For example, the controller 75 controls the motor drivers 71 and 72 such that the torque of the motor 60 increases as the amount of strain detected by the first strain gauge 81 increases. Furthermore, if the first strain gauge 81 fails, the controller 75 controls the motor drivers 71 and 72 based on the detection result of the second strain gauge 82. Alternatively, the controller 75 may control the motor drivers 71 and 72 such that the torque of the motor 60 increases as the average value of the strain amounts detected by the strain gauges 81 and 82 increases. Also, if one of the strain gauges 81 or 82 fails, the controller 75 may control the first motor driver 71 and the second motor driver 72 based on the detection result of the other strain gauge.

[0033] Furthermore, the controller 75 controls the motor drivers 71 and 72 to limit the speed of the electric kick scooter 10 to the maximum speed vm or less if the speed v detected by the speed sensor 90 exceeds the maximum speed vm. The maximum speed vm is, for example, 20 km / h (a predetermined low speed).

[0034] As shown in Figures 1 and 3, a pair of left and right brackets 18 (support members) are attached to the vehicle body 11 (only the left bracket 18 is shown). The pair of left and right brackets 18 rotatably support the rear wheel 14. Note that the cover 19 is not shown in Figure 3.

[0035] The motor 60 is fixed (mounted) to the left bracket 18. A circuit board 76 is fixed (mounted) to one end 60a of the motor 60 in the longitudinal direction (axial direction of the output shaft 65) via the bracket 18. The circuit board 76 is equipped with a first motor driver 71, a second motor driver 72, and a controller 75. The first stator winding 61 and the first motor driver 71 are connected by wiring through holes or notches (not shown) formed in the bracket 18. The second stator winding 62 and the second motor driver 72 are connected by wiring through holes or notches (not shown) formed in the bracket 18. The longitudinal end face of the motor 60, the main surface (largest surface) of the bracket 18, and the plate surface (main surface) of the circuit board 76 are parallel (approximately parallel). The circuit board 76 is covered by a cover 19.

[0036] On the circuit board 76, a connector 77 is attached to the second surface 76b, which is opposite to the first surface 76a on which the motor drivers 71, 72 and controller 75 are mounted. The connector 77 is connected to the motor drivers 71, 72 and controller 75 by printed wiring etc. (not shown) formed on the circuit board 76. The motor 60 and the connector 77 are arranged adjacent to each other (in parallel) on the second surface 76b side of the circuit board 76. The longitudinal direction of the motor 60 and the longitudinal direction of the connector 77 coincide with the vehicle width direction of the electric kick scooter 10. A connector 78 attached to the end of the wiring 79 is connected to the connector 77. The wiring 79 includes power lines connected to the battery 40 and signal lines connected to the first strain gauge 81, the second strain gauge 82, and the speed sensor 90, respectively. The wiring 79 is connected to the motor drivers 71, 72, and controller 75, respectively, via connectors 78, 77, and printed wiring etc. on the circuit board 76.

[0037] The controller 75 further performs the following control: the controller 75 executes multiple control modes for controlling the motor 60. These multiple control modes include a torque control mode for controlling the torque of the motor 60, a rotational speed control mode for controlling the rotational speed of the motor 60 by regenerating power using the motor 60, and a rotational position control mode for controlling the rotational position of the motor 60. The controller 75 selects and executes one of the above multiple control modes according to the intentions of the driver of the electric kick scooter 10.

[0038] More specifically, the controller 75 determines whether the electric kick scooter 10 is accelerating, traveling at a constant speed, decelerating, or stopped, based on the detection result of at least one of the strain gauges 81, 82 and the speed sensor 90. For example, the controller 75 determines that it is accelerating when the amount of strain detected by the first strain gauge 81 is increasing. The controller 75 determines that it is decelerating when the amount of strain detected by the first strain gauge 81 is decreasing. The controller 75 determines that it is traveling at a low speed when the amount of strain detected by the first strain gauge 81 is constant, or when the speed v detected by the speed sensor 90 is constant. The controller 75 determines that it is stopped when the speed v detected by the speed sensor 90 is approaching 0 [km / h].

[0039] The controller 75 executes a torque control mode when it determines that the electric kick scooter 10 is accelerating or traveling at a constant speed. In torque control mode, the controller 75 calculates a torque command value for the motor 60 based on the detection result of at least one of the strain gauges 81 and 82. The controller 75 then controls the motor drivers 71 and 72 to make the torque output by the motor 60 match the torque command value. For example, the controller 75 controls the current flowing through the stator windings 61 and 62 based on the torque command value using well-known feedback control or the like.

[0040] The controller 75 executes a rotation speed control mode when it determines that the electric kick scooter 10 is decelerating. In rotation speed control mode, the controller 75 calculates a rotation speed command value for the motor 60 based on the detection result of at least one of the strain gauges 81 and 82. The controller 75 then controls the motor drivers 71 and 72 to reduce the rotation speed of the motor 60 to the rotation speed command value by regenerative power generation. For example, the controller 75 controls the generated current flowing through the stator windings 61 and 62 based on the rotation speed command value.

[0041] The controller 75 executes a rotation position control mode when it determines that the electric kick scooter 10 is stopped. In rotation position control mode, the controller 75 calculates a rotation position command value for the motor 60 based on the detection result of at least one of the strain gauges 81 and 82. The controller 75 then controls the motor drivers 71 and 72 to set the rotation position of the motor 60 to the rotation position command value. For example, the controller 75 controls the current flowing through the stator windings 61 and 62 based on the rotation position command value.

[0042] Furthermore, if one of the stator windings 61 or 62 is disconnected, the controller 75 controls the corresponding first motor driver 71 or second motor driver 72 to supply power to the other stator winding, thereby continuing to drive the motor 60. Note that the disconnection of one of the stator windings 61 or 62 can be determined, for example, based on the current flowing through the stator windings 61 or 62. Additionally, if one of the motor drivers 71 or 72 fails, the controller 75 controls the other motor driver to supply power to the corresponding first stator winding 61 or second stator winding 62, thereby continuing to drive the motor 60. Note that the failure of one of the motor drivers 71 or 72 can be determined, for example, based on the operating state of the inverter circuits constituting the motor drivers 71 or 72.

[0043] When the driver operates the electric kick scooter 10, they place one foot on the deck 11a and push off the ground with the other foot to start the electric kick scooter 10. Then, when the driver rotates the accelerator grip 21 backward (towards them), the controller 75 executes torque control mode to accelerate the electric kick scooter 10. When the driver rotates the accelerator grip 21 forward (away from them), the controller 75 executes rotation speed control mode to generate regenerative power using the motor 60. When the driver grips either the brake lever 26 or 27 and the speed v of the electric kick scooter 10 approaches 0 [km / h], the controller 75 executes rotation position control mode to control the rotation position of the motor 60 to the rotation position command value.

[0044] Furthermore, even if one of the stator windings 61 or 62 breaks, or if one of the motor drivers 71 or 72 malfunctions, the controller 75 will continue to drive the motor 60. As a result, the driver can continue to operate the electric kick scooter 10 and does not need to push it to move it.

[0045] The embodiment described in detail above has the following advantages.

[0046] The motor 60 comprises a rotor 63 and two stator windings 61 and 62 (motor windings). Two motor drivers 71 and 72 each change the amount of power supplied to the two stator windings 61 and 62. The accelerator sensor 80 detects the amount of strain (operation amount correlation value) of a torsion member 83 that correlates with the amount of operation of the accelerator grip 21 of the electric kick scooter 10. The controller 75 then controls the two motor drivers 71 and 72. Therefore, even if one of the two stator windings 61 and 62 is disconnected, the motor 60 can still be rotated by supplying power to the other stator winding. Also, even if one of the two motor drivers 71 and 72 fails, the motor 60 can still be rotated by changing the power supplied to the corresponding stator winding by the other motor driver. Therefore, the drive system of the electric kick scooter 10 can improve the ability to continue driving the electric kick scooter 10 in the event of a break in the stator windings 61 and 62 or a failure of the motor drivers 71 and 72.

[0047] The motor 60, the two motor drivers 71 and 72, and the controller 75 are integrated into a single motor module 50. This reduces the complexity of the wiring connecting them and prevents disconnections in the connecting wires. In particular, when the motor 60 has two stator windings 61 and 62, and the drive unit has two motor drivers 71 and 72 and a controller 75, the wiring connecting them becomes more complex and prone to disconnections. Therefore, integrating them into a single motor module 50 further enhances the above effect.

[0048] The controller 75 is capable of executing multiple control modes for controlling the motor 60. Therefore, the control mode can be switched according to the state of the electric kick scooter 10, which can suppress power consumption or improve power utilization efficiency. Thus, even if it is difficult to install a large-capacity battery in the electric kick scooter 10, the continuous operation of the electric kick scooter 10 can be improved.

[0049] A circuit board 76, on which motor drivers 71 and 72 and a controller 75 are mounted, is attached to one end 60a of the motor 60 in the longitudinal direction. This allows the motor drivers 71 and 72 and the controller 75 to be arranged together at one end 60a of the motor 60 in the longitudinal direction. A connector 77 for connecting wiring 79 to the motor drivers 71 and 72 and the controller 75 is attached to the circuit board 76. This allows the wiring 79 to be connected to the motor drivers 71 and 72 and the controller 75 via the connector 77 and the circuit board 76. The motor 60 and the connector 77 are arranged in parallel, and the longitudinal direction of the motor 60 and the longitudinal direction of the connector 77 coincide. This reduces the space required to arrange the motor 60 and the connector 77. Furthermore, because the longitudinal direction of the motor 60 and the longitudinal direction of the connector 77 coincide with the width direction of the electric kick scooter 10, the width of the electric kick scooter 10 can be reduced.

[0050] The controller 75 controls the corresponding first motor driver 71 or second motor driver 72 to supply power to the other stator winding if one of the two stator windings 61 or 62 breaks, thereby continuing to drive the motor 60. With this configuration, even if one of the two stator windings 61 or 62 breaks, the motor 60 can continue to drive, and the electric kick scooter 10 can continue to run. Therefore, it is possible to avoid a situation where the electric kick scooter 10 has to be pushed to move.

[0051] The controller 75 controls the other motor driver to supply power to the corresponding first stator winding 61 or second stator winding 62 if one of the two motor drivers 71 or 72 fails, thereby continuing to drive the motor 60. With this configuration, even if one of the two motor drivers 71 or 72 fails, the motor 60 can continue to drive, and the electric kick scooter 10 can continue to run. Therefore, it is possible to avoid a situation where the electric kick scooter 10 has to be pushed to move.

[0052] The multiple control modes include a torque control mode for controlling the torque of the motor 60, a rotational speed control mode for controlling the rotational speed of the motor 60 by regenerating power using the motor 60, and a rotational position control mode for controlling the rotational position of the motor 60. With this configuration, the torque control mode, rotational speed control mode, and rotational position control mode can be switched according to the intentions of the driver of the electric kick scooter 10, thereby suppressing power consumption or improving the efficiency of power utilization. Furthermore, the controller 75 can serve as both a motor controller for controlling the motor 60 and a vehicle controller for controlling the entire electric kick scooter 10.

[0053] The controller 75 executes a torque control mode when the electric kick scooter 10 is accelerating and driving at a constant speed, making it easier to drive the electric kick scooter 10 according to the driver's intentions. The controller 75 executes a rotation speed control mode when the electric kick scooter 10 is decelerating, allowing the motor 60 to regenerate power and effectively utilize energy during deceleration. The controller 75 executes a rotation position control mode when the electric kick scooter 10 is stopped, making it easier to stop the electric kick scooter 10 according to the driver's intentions.

[0054] The accelerator sensor 80 includes a torsional member 83 that deforms torsionally in response to the amount of operation of the accelerator grip 21, and two strain gauges 81 and 82 that detect the amount of strain (torsional deformation) of the torsional member 83. Therefore, the correlation value of the operation amount detected by the accelerator sensor 80 can be suppressed from being directly affected by fluctuations in the voltage supplied from the battery 40 to the accelerator sensor 80. Consequently, the control state of the motor 60, which is controlled based on the amount of strain detected by the accelerator sensor 80, can be suppressed from being affected by the supply voltage of the battery 40. Moreover, even if one of the two strain gauges 81 and 82 fails, the correlation value of the operation amount of the accelerator grip 21 can still be detected by detecting the amount of strain of the torsional member 83 using the other strain gauge. Therefore, the robustness of the accelerator sensor 80 against failure can be improved.

[0055] The accelerator sensor 80 and the motor module 50 can directly exchange power and strain (signal). Therefore, there is no need for relay devices or the like between the accelerator sensor 80 and the motor module 50, and the configuration and processing can be simplified.

[0056] Furthermore, the above embodiment can also be implemented with the following modifications. Parts identical to those in the above embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0057] The rotation speed of the motor 60 may be controlled when the electric kick scooter 10 is traveling at a constant speed. Furthermore, the rotation position control mode may be disabled when the electric kick scooter 10 is stopped.

[0058] A gear reducer can also be used as the power transmission device that transmits power from the output shaft 65 of the motor 60 to the rear wheels 14.

[0059] The connector 77 can be positioned on the second surface 76b of the circuit board 76, and the longitudinal direction of the connector 77 can be perpendicular (or nearly perpendicular) to the output shaft 65. Even in this case, the width of the electric kick scooter 10 can be reduced.

[0060] The accelerator sensor 80 (operated amount sensor) may include a first torsional member (first deformation member) and a second torsional member (second deformation member), where a first strain gauge 81 detects the amount of strain of the first torsional member and a second strain gauge 82 detects the amount of strain of the second torsional member.

[0061] The electric kick scooter 10 may be equipped with an accelerator lever instead of an accelerator grip 21. In that case, the shapes of the twisting member 83, the first twisting member, and the second twisting member can be changed according to the shape of the accelerator lever.

[0062] The motor module 50 may include a first controller that controls the first motor driver 71 and a second controller that controls the second motor driver 72.

[0063] • The motor 60 is not limited to a permanent magnet type 3-phase brushless motor; it may also be a field winding type 3-phase brushless motor.

[0064] The specific small motorized bicycle (low-speed electric vehicle) to which the drive system of the above embodiment and modified example is applied is not limited to the electric kick scooter 10, but may also be a senior scooter, a golf cart, etc. Furthermore, the above embodiment and modified example may be applied to any low-speed electric vehicle with a maximum speed of 30 km / h (a predetermined low speed) or less, not limited to the specific small motorized bicycle.

[0065] Furthermore, it is possible to combine and implement the above examples of changes.

[0066] The following describes the characteristic configurations extracted from the embodiments and modifications described above. [Configuration 1] A drive unit for driving a low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module (50). The controller is a drive system for a low-speed electric vehicle, capable of executing multiple control modes for controlling the motor. [Configuration 2] A drive system for a low-speed electric vehicle according to Configuration 1, wherein a circuit board (76) on which the motor driver and the controller are mounted is attached to one longitudinal end (60a) of the motor, a connector (77) for connecting wiring (79) to the motor driver and the controller is attached to the circuit board, the motor and the connector are arranged in parallel, and the longitudinal direction of the motor and the longitudinal direction of the connector coincide. [Configuration 3] The drive system for a low-speed electric vehicle according to configuration 1 or 2, wherein the output shaft (65) of the motor is connected to the wheel (14) of the low-speed electric vehicle via a power transmission device (15, 16). [Structure 4] The drive system for a low-speed electric vehicle according to any one of configurations 1 to 3, wherein the controller controls the corresponding motor driver to supply power to the other stator winding when one of the two stator windings is disconnected, thereby continuing to drive the motor. [Composition 5] The drive system for a low-speed electric vehicle according to any one of configurations 1 to 3, wherein the controller controls the other motor driver to supply power to the corresponding stator winding in the event of a failure of one of the two motor drivers, thereby continuing to drive the motor. [Composition 6] The drive system for a low-speed electric vehicle according to any one of configurations 1 to 5, wherein the plurality of control modes include a torque control mode for controlling the torque of the motor, a rotational speed control mode for controlling the rotational speed of the motor by regenerating power generation using the motor, and a rotational position control mode for controlling the rotational position of the motor. [Composition 7] The drive system for a low-speed electric vehicle according to configuration 6, wherein the controller executes the torque control mode when the low-speed electric vehicle is accelerating and driving at a constant speed, executes the rotational speed control mode when the low-speed electric vehicle is decelerating, and executes the rotational position control mode when the low-speed electric vehicle is stopped. [Explanation of Symbols]

[0067] 10...Electric kick scooter, 21...Accelerator grip, 50...Motor module, 60...Motor, 61...First stator winding, 62...Second stator winding, 63...Rotor, 71...First motor driver, 72...Second motor driver, 75...Controller, 80...Accelerator sensor, 81...First strain gauge, 82...Second strain gauge, 83...Torsion member.

Claims

1. A drive system for driving a low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module (50). The output shaft (65) of the motor is connected to the drive wheel (14) of the low-speed electric vehicle via a sprocket (15) and a chain (16). The motor is attached to a bracket (18) that supports the drive wheel of the low-speed electric vehicle. The controller is a drive system for a low-speed electric vehicle, capable of executing multiple control modes for controlling the motor.

2. A drive system for a low-speed electric vehicle according to claim 1, wherein a circuit board (76) on which the motor driver and the controller are mounted is attached to one longitudinal end (60a) of the motor, a connector (77) for connecting wiring (79) to the motor driver and the controller is attached to the circuit board, the motor and the connector are arranged in parallel, and the longitudinal direction of the motor and the longitudinal direction of the connector coincide.

3. The drive system for a low-speed electric vehicle according to claim 1 or 2, wherein the output shaft (65) of the motor is connected to the wheel (14) of the low-speed electric vehicle via a power transmission device (15, 16).

4. The drive system for a low-speed electric vehicle according to claim 1 or 2, wherein the controller controls the corresponding motor driver to supply power to the other stator winding when one of the two stator windings is disconnected, thereby continuing to drive the motor.

5. The drive system for a low-speed electric vehicle according to claim 1 or 2, wherein the controller controls the other motor driver to supply power to the corresponding stator winding in the event of a failure of one of the two motor drivers, thereby continuing to drive the motor.

6. The drive system for a low-speed electric vehicle according to claim 1 or 2, wherein the plurality of control modes include a torque control mode for controlling the torque of the motor, a rotational speed control mode for controlling the rotational speed of the motor by regenerating power generation using the motor, and a rotational position control mode for controlling the rotational position of the motor.

7. The drive system for a low-speed electric vehicle according to claim 6, wherein the controller executes the torque control mode when the low-speed electric vehicle is accelerating and driving at a constant speed, executes the rotational speed control mode when the low-speed electric vehicle is decelerating, and executes the rotational position control mode when the low-speed electric vehicle is stopped.

8. A low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, The aforementioned low-speed electric vehicle is The vehicle comprises a body (11), a frame (12), front wheels (13), rear wheels (14), handlebars (20), a battery (40), and a motor module (50). The motor module is A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, The motor, the two motor drivers, and the controller are integrated into a single module and are fixed to a bracket (18) that rotatably supports the rear wheel of the vehicle body. A low-speed electric vehicle in which the output shaft (65) of the motor is connected to the rear wheel (14) via a sprocket (15) and a chain (16).

9. A low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, The aforementioned low-speed electric vehicle is The vehicle comprises a body (11), a frame (12), front wheels (13), rear wheels (14), handlebars (20), a battery (40), and a motor module (50). The motor module is A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, A low-speed electric vehicle in which the motor, the two motor drivers, and the controller are integrated into a single module and positioned between the battery and the rear wheel.

10. A low-speed electric vehicle (10) whose maximum speed is less than or equal to a predetermined low speed, The aforementioned low-speed electric vehicle is The vehicle comprises a body (11), frame (12), front wheel (13), rear wheel (14), handlebars (20), battery (40), motor module (50), accelerator grip (21), and brake lever (26), The front wheel is attached to the lower part of the frame, and the handlebars are attached to the upper part of the frame. The aforementioned accelerator grip and brake lever are attached to the handlebars. The motor module is A motor (60) comprising a rotor (63) and two stator windings (61, 62), Two motor drivers (71, 72) that change the power supplied to the two stator windings, A controller (75) that controls the two motor drivers, Equipped with, A low-speed electric vehicle in which the motor, the two motor drivers, and the controller are integrated into a single module and positioned between the battery and the rear wheel.

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