Vehicle control unit and running body

Abstract

To provide a vehicle control unit that can effectively prevent a motor driving circuit from being damaged when an electric two-wheel vehicle is running on a slope road while turning off an electric motor, and a running body.SOLUTION: A vehicle control unit, which is connected to a first power supply through a connector, comprises: a motor driving circuit that drives an electric motor; a control part that outputs a control signal for controlling rotation of the electric motor to the motor driving circuit; and an internal power supply circuit having an enable terminal to which an input end of the motor driving circuit is connected. The vehicle control unit is configured so that voltages that are induced when the electric motor rotates at predetermined rotation speed or higher activate the internal power supply circuit, with the connector opened. When the internal power supply circuit is activated with the connector opened, the control part outputs a command signal for commanding the connector to be closed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control unit used for a traveling body such as a two-wheeled vehicle or other three-wheeled vehicle having a motor as a drive source, and to such a traveling body.

Background Art

[0002] In recent years, the demand for two-wheeled vehicles with an electric motor having a throttle as a speed adjustment mechanism has been expanding. For example, Patent Document 1 describes a motor drive circuit with enhanced functionality for motor control mounted on an electric two-wheeled vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric two-wheeled vehicle, generally, in-vehicle power can be charged with the regenerative power of an electric motor as a drive source. Due to such characteristics of an electric two-wheeled vehicle, a driver may act in a way to reduce power consumption or improve charging efficiency by devising the riding method. For example, the driver may start going down a slope with the main switch and start switch of the electric two-wheeled vehicle turned off, and turn on the switch when a certain speed is reached. That is, in order to reduce the power consumption of the electric two-wheeled vehicle, the driver goes down a slope without starting the electric motor of the electric two-wheeled vehicle. When the electric motor is not running and the electric motor is rotated excessively, a large induced voltage is generated, which may damage the motor drive circuit and cause breakdown of the device's withstand voltage. As a countermeasure against the breakdown of the device's withstand voltage, it is assumed that a device with a high withstand voltage is selected for the generated induced voltage, the connection to the motor is cut off and the three phases are shorted, or the motor size and the shape of the winding are changed to lower the generated induced voltage. However, when a device with a high withstand voltage is selected, especially in the case of a driving device, the higher the withstand voltage, the higher the impedance, resulting in a higher cost. From the perspective of efficiency and cost, it does not become a system with advantages, and the superiority as an electric two-wheeler is impaired. Also, the method of cutting off the connection to the motor can be said to be a very effective method from the perspective of protecting the drive circuit. However, since the heat generation of the motor increases and many other components such as a contactor are required between the inverter and the motor, the system cost increases. In addition, when taking countermeasures on the motor side, the cost also increases because it is necessary to upgrade the grade of the magnet and increase the motor size.

[0005] The present invention has been made in view of such circumstances, and its object is to provide a vehicle control unit and a traveling body that can effectively prevent damage to the motor drive circuit during traveling on a slope when the electric motor of an electric two-wheeler is off.

Means for Solving the Problems

[0006] In order to achieve such an object, the technical means according to the present invention is a vehicle control unit that at least includes the following configuration.

[0007] A vehicle control unit connected to a first power source via a contactor, the vehicle control unit comprising: a motor drive circuit for driving an electric motor; a control unit for outputting a control signal for controlling the rotation of the electric motor to the motor drive circuit; and an internal power supply circuit having an enable terminal to which an input terminal of the motor drive circuit is connected, wherein the vehicle control unit is configured such that a voltage induced when the electric motor rotates at a predetermined speed or more in an open state of the contactor activates the internal power supply circuit, and when the internal power supply circuit is activated in the open state of the contactor, the control unit outputs a command signal to close the contactor.

[0008] In order to achieve the above object, a technical means according to the present invention is a traveling body that at least includes the following configuration.

[0009] A traveling body including a vehicle control unit connected to a first power source via a contactor, the vehicle control unit having: a motor drive circuit for driving an electric motor; a control unit for outputting a control signal for controlling the rotation of the electric motor to the motor drive circuit; and an internal power supply circuit having an enable terminal to which an input terminal of the motor drive circuit is connected, wherein the vehicle control unit is configured such that a voltage induced when the electric motor rotates at a predetermined speed or more in an open state of the contactor activates the internal power supply circuit, and when the internal power supply circuit is activated in the open state of the contactor, the control unit outputs a command signal to close the contactor.

Effects of the Invention

[0010] By having such a feature, according to the present invention, it is possible to effectively prevent damage to the motor drive circuit during traveling on a slope when the electric motor of an electric two-wheeler is turned off.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0012] Hereinafter, examples of embodiments of a vehicle control unit according to the present invention will be described with reference to the drawings. However, the following drawings are created for the purpose of explanation, and in some cases, members unnecessary for explanation may not be intentionally illustrated. Also, for the purpose of explanation, members may be intentionally illustrated larger or smaller, and the drawings do not show the exact scale. In the following description, the same reference numerals in different figures indicate parts having the same function, and duplicate descriptions in each figure are omitted as appropriate.

[0013] <Embodiment> (System Configuration) FIG. 1 is a system configuration diagram of a vehicle control unit according to an embodiment of the present invention. In this embodiment, the vehicle control unit 1 controls and drives a motor 3 mounted near the rear wheel of an electric two-wheeler. In the embodiment of the present invention, a first power source 2 as a motor drive power source which is a 48V lithium-ion battery and a second power source 4 as a unit control power source which is a 12V lead battery are connected to the vehicle control unit 1. As another embodiment, it is also possible to adopt a configuration without the second power source 4.

[0014] The vehicle control unit 1 includes a series regulator 11 as an internal power supply circuit, a control unit 12 for generating, for example, a PWM signal or the like to drive and control the motor 3, and a motor drive circuit 13 including six power transistors.

[0015] The series regulator 11 has the output from the main switch and the key switch 15 connected to its enable terminal. When the main switch or the key switch is operated, a constant voltage of about 5V is applied to the enable terminal, and the series regulator 11 is activated. Also, the series regulator 11 has the first power supply 2 divided by the contactor 21 connected to its enable terminal. This voltage division ratio is set assuming the influence of the DC link capacitor so as to be an appropriate voltage value for activating the series regulator 11 by the induced voltage generated from the motor 3 when starting on a slope, which will be described later.

[0016] The control unit 12 receives signals from the main switch or the key switch 15 and also from the throttle 16 provided on the handle of the electric two-wheeler. The control unit 12 generates, for example, a PWM signal for driving the circuits for normal motor control and charging control in response to the operation applied to the throttle 16 and the operation applied to a brake (not shown). In addition to this, circuit protection control is also executed, which will be described later.

[0017] The motor drive circuit 3 has six power transistors and a current detection resistor (not shown), and supplies a predetermined drive current to the motor 3 based on, for example, a PWM control signal from the control unit 12. Here, the six power transistors are NMOS transistors, and each is provided with a fast recovery diode between the source and the drain. The drains of the upper three power transistors in the figure are connected to the first power supply 2 via the contactor 21, and the sources of the lower three power transistors in the figure are grounded.

[0018] The sources of the upper three power transistors in the figure are commonly connected to the drains of the lower three power transistors in the figure, and drive current is supplied from each of these connection nodes to the U-phase, V-phase, and W-phase of the motor 3.

[0019] The control unit 12 of the vehicle control unit 1 also outputs a signal to the battery management system 14. The battery management system 14 performs thermal control of the first power source 2, and also detects an abnormal state due to overcurrent and outputs a signal for cutting off the vehicle control unit 1 and the first power source 2 to the contactor 21. Further, the battery management system 14 also performs monitoring and predictive calculations of voltage, current, temperature, SOC, etc.

[0020] In order to use the battery safely and effectively and to prevent damage to electronic devices, the vehicle control unit 1 performs important functions. For example, in order to reduce the power consumption of an electric two-wheeler, when the driver tries to cut off the main switch of the electric two-wheeler once while the electric two-wheeler is running on a slope to eliminate power consumption, if the vehicle speed is above a certain level even when the main switch is turned off, the battery management system 14 does not immediately turn off the vehicle control unit 1, but cancels the back electromotive force by PWM control to prevent breakdown of the withstand voltage of the circuit device. This can be called circuit protection control during slope driving. However, this circuit protection control during slope driving is possible because the vehicle control unit 1 is operating. If the vehicle control unit 1 is not activated, breakdown of the withstand voltage of the device cannot be prevented. It is possible for the electric two-wheeler to run with the vehicle control unit 1 not activated. This is the case when starting on a slope where the driver starts the electric two-wheeler with the main switch of the electric two-wheeler stopped on a slope turned off. The vehicle control unit according to the embodiment of the present invention can effectively prevent breakdown of the withstand voltage of the device even in such a situation. This will be described below.

[0021] (Operation sequence) While showing FIG. 1, the operation sequence of the vehicle control unit according to the embodiment of the present invention will be described. When the vehicle control unit 1 to which the first power source 2 and the second power source 4 are connected is in the system-off state, the contactor 21 is in the open state, and the 5V output of the series regulator 11 is off. The series regulator 11 starts its output by voltage input to the enable terminal. When the contactor is closed and the voltage of the second power source 4 is input to the enable terminal by the operation of the driver's key switch or main switch, the series regulator 11 starts up. This operation is the startup operation of the series regulator 11 during normal times and is a normal startup.

[0022] Next, the startup during starting on a slope, which is a feature of the present invention, that is, the emergency startup which is the startup in an emergency will be described. When starting to ride an electric two-wheeler so as to go down a slope by its own weight without operating the key switch or main switch of the electric two-wheeler, the motor 3 mounted near the rear wheel of the electric two-wheeler will be forcibly rotated. Then, a change occurs in the magnetic flux passing through the coil of the motor 3, and an induced voltage is generated. When the motor induced voltage is generated, a voltage is applied to the enable terminal of the series regulator 11 through the fast recovery diodes of the upper three power transistors in the illustration of the motor drive circuit 13. For example, the voltage division ratio of the voltage dividing resistors is adjusted so that a voltage sufficient for the series regulator 11 to start up is applied to the enable terminal when a voltage above a certain induced voltage such as 30Vpeak at 3000 rpm is generated.

[0023] More specifically, the voltage division ratio is adjusted so that the voltage applied to the series regulator 11 is the same during normal startup and emergency startup. In other words, the voltage division ratio is adjusted so that the induced voltage at the time of regulator startup is below the voltage of the drive power source. The value of this applied voltage corresponds to the induced voltage of 30Vpeak at 3000 rpm described above. The reason for setting it like this is that it is desirable for the system to start up in a state where the induced voltage by the motor 3 is below the voltage of the first power source 2 so that no voltage backflow occurs when the contactor 21 is closed.

[0024] When the motor 3 rotates and about 4V is input to the enable terminal, the series regulator 11 is activated, and the control unit 12 is also activated. Thereafter, the control unit 12 continues to operate with the power from the second power source 4. However, during the continued operation, the control unit 12 disconnects the supply line from the motor so as not to exceed the withstand voltage of the enable terminal of the series regulator 11.

[0025] The fact that the control unit 12 is activated by a method other than normal input is determined by the state of the contactor 21, the voltage monitor value of the first power source 2, the rotational speed of the motor, etc. That is, it becomes possible to determine that it is an emergency start. The control unit 12 that has determined that it is an emergency start communicates with the battery management system 14 and instructs it to close the contactor 21.

[0026] When the contactor 21 is closed, power is supplied from the first power source 2, and the vehicle control unit 1 starts a control operation by PWM control. As a countermeasure against device withstand voltage breakdown, zero torque control is performed. Specifically, the voltage command of the motor is controlled so that the driving torque of the motor becomes zero to cancel the induced voltage. In addition, torque control by throttle operation performed in normal operation is prohibited. Specifically, the control unit 12 invalidates the throttle input.

[0027] Regarding the operation sequence described above, it will be described as the sequence of each system. FIG. 2 is an explanatory diagram showing the operation sequence of the vehicle control unit according to the embodiment of the present invention, and shows the vehicle state, the generated action, the action in the control unit, and the action in the battery management system arranged side by side.

[0028] As the vehicle state, first, the steering wheel is not locked and starts from the state where the main switch is off. Since the driver is about to get out, naturally, the steering wheel lock is released. However, the driver will start the electric two-wheeler while keeping the main switch of the electric two-wheeler stopped on a slope turned off so as not to consume power.

[0029] When the rear wheel of the electric two-wheeler rotates, eventually, the motor 3 will be forced to rotate at a predetermined number or more, such as 3000 rpm.

[0030] As the rotor of the motor rotates, the magnetic field of the magnet attached to the rotor causes electromagnetic induction with respect to the stator winding of the motor. An induced voltage is generated by the induced current generated by this action and is applied to the vehicle control unit 1. This induced voltage is basically a sine wave and is smoothed by the DC link capacitor through the fast recovery diodes of the upper three power transistors in the illustration of the motor drive circuit 13. This smoothed voltage is applied to the enable terminal of the series regulator 11. In response to the enable command, the series regulator 11 is supplied with the power of the 12V second power source as the main power source. Then, after the control unit 12 executes the same process as the initial target diagnosis process executed during normal startup, it starts up, and the vehicle control unit 1 is turned on. The vehicle control unit 1 determines that it is an emergency startup by checking that the contactor 21 is open, etc.

[0031] The vehicle control unit 1 that has determined that it is an emergency startup sends a command signal to the battery management system 14 to close the contactor 21 so that the power from the 48V first power source is supplied. When the supply of 48V power from the first power source starts, smart authentication is executed to check whether the driver has a legitimate key.

[0032] After that, the vehicle control unit 1 executes the necessary PWM control. Specifically, it executes zero torque control in which no lost torque occurs with respect to vehicle operation and the neutral state is achieved. In the motor drive circuit, an induced voltage more than necessary is not transmitted, and breakdown of the device due to withstand voltage is prevented. Also, in the case of a steep slope or a situation where the slope continues for a long time and the speed becomes too high, brake torque control is executed to suppress the speed from increasing by applying a brake equivalent to regeneration. When starting an electric two-wheeler after parking and charging at a residence or the like, it is often fully charged, and in such a case, braking is applied with regeneration prohibited. The regenerative current is appropriately consumed within the vehicle control unit 1.

[0033] On the other hand, if the vehicle control unit 1 according to the embodiment of the present invention is not in the fully charged state, it detects this and executes regenerative torque control in which vehicle operation is suppressed by a regenerative brake so that the speed does not easily increase. That is, regenerative charging is to be executed.

[0034] In this embodiment, every 5 seconds, the motor rotation speed is monitored, and PWM control for circuit protection is continued until it becomes zero. When the rotation speed becomes zero, the vehicle control unit 1 sends a command signal to the battery management system 14 to open the contactor 21 so that power from the 48V first power source is not supplied. Before that, if the main switch is turned on, such monitoring is not performed because it shifts to the normal state.

[0035] <Another Embodiment> Another embodiment without a second power source will be described with reference to FIGS. 3 and 4. FIG. 3 is a system configuration diagram of a vehicle control unit according to another embodiment of the present invention. The vehicle control unit 1A does not include a second power source but includes a communication unit 5. FIG. 4 is an explanatory diagram showing the operation sequence of the vehicle control unit according to another embodiment of the present invention, arranging the vehicle state, the action that occurs, the action in the control unit, the action in the communication unit, and the action in the battery management system.

[0036] As vehicle states, the point that the steering wheel is not locked and starting from the state where the main switch is off, and the point that the rear wheel of the electric two-wheeler rotates and eventually the motor 3 is forced to rotate at a predetermined number or more such as 3000 rpm are the same as those in the previously shown embodiment.

[0037] Since the second power supply is not connected to the vehicle control unit 1A, the fact that an induced voltage has occurred is transmitted to the communication unit 5 by CAN communication. Further, the communication unit 5 instructs the battery management system 14 to supply power from the 48V first power supply to the vehicle control unit 1A. In a conventional circuit without a circuit protection processing function during starting on a slope, smart authentication is performed only when the main switch or the key switch is turned on. In the embodiments of the present invention and another embodiment corresponding to a situation where the main switch is not operated, smart authentication is performed when power is supplied from the 48V first power supply. When 48V power is appropriately divided and supplied to the series regulator 11, the control unit 12 starts after executing a process in which a part of the initial target diagnosis process executed during normal startup is omitted, and the vehicle control unit 1A is turned on. In another embodiment, since the power up to the contact closing command is covered by the motor induced voltage, startup in a short time is required. For this reason, the initial diagnosis target is reduced to shorten the startup time of the control unit.

[0038] After that, the vehicle control unit 1A executes the necessary PWM control. Specifically, it executes zero torque control in which no lost torque occurs with respect to vehicle operation and the neutral state is achieved. In the motor drive circuit, an induced voltage more than necessary is not transmitted, and breakdown voltage of the device is prevented. Also, in the case of a steep slope or a situation where the slope continues for a long time and the speed increases too much, brake torque control is executed to apply a brake equivalent to regeneration to make it difficult for the speed to increase. On the other hand, if it is not in the fully charged state, this is detected, and while executing regeneration torque control to suppress the vehicle operation with a regenerative brake to make it difficult for the speed to increase, regeneration charging is executed.

[0039] Also in another embodiment, every 5 seconds, the motor speed is monitored, and the PWM control for circuit protection is continued until it becomes zero. When the speed becomes zero, the vehicle control unit 1 sends a command signal to the battery management system 14 to open the contactor 21 so that the power from the 48V first power source is not supplied. Before that, if the main switch is turned on, such monitoring is not performed because it shifts to the normal state.

[0040] As described above in detail for the vehicle control unit according to the embodiment of the present invention and the traveling body equipped with the vehicle control unit, the specific configuration is not limited to these embodiments, and even if there are design changes and the like within the scope not departing from the gist of the present invention, they are included in the present invention. For example, as the circuit board, the internal power supply circuit has been described by way of example of a series regulator, but the internal power supply circuit may be configured by a DCDC converter. Also, although the traveling body as the target has been described as an electric two-wheeler, it can also be applied to electric three-wheelers such as electric three-wheel bikes with two front wheels or commercial electric scooters for delivery with two rear wheels. For the type with two rear wheels, two motors may be provided. As described in this specification, in a situation where the system is not activated, by utilizing the induced voltage from the motor to activate the system and then performing subsequent circuit protection processing, the characteristic configuration of the vehicle control unit, in other words, the characteristic configuration that can achieve effective circuit protection without arranging particularly different hardware elements or the like compared to the previous system, should be correctly recognized.

Explanation of Reference Signs

[0041] 1 Vehicle control unit 1A Vehicle control unit 11 Series regulator (internal power supply circuit) 12 Control unit 13 Motor drive circuit 14 Battery management system 15 Main switch, key switch 16 Throttle 2 First power supply 21 Contact 3 Motor 4 Second power supply 5 Communication unit

Claims

1. A vehicle control unit connected to a first power source via a contactor, wherein the vehicle control unit includes a motor drive circuit for driving an electric motor, a control unit that outputs a control signal for controlling the rotation of the electric motor to the motor drive circuit, and an internal power supply circuit having an enable terminal to which an input terminal of the motor drive circuit is connected, wherein the vehicle control unit is configured such that when the electric motor rotates at a predetermined speed or more in an open state of the contactor, a voltage induced thereby activates the internal power supply circuit, and when the internal power supply circuit is activated in the open state of the contactor, the control unit outputs a command signal to close the contactor A vehicle control unit characterized by the above.

2. The vehicle control unit when the internal power supply circuit is activated in the open state of the contactor, a part of the initial target diagnostic process executed during normal startup is omitted, and the control unit is activated The vehicle control unit according to claim 1, characterized by the above.

3. The vehicle control unit further includes a second power source, when the internal power supply circuit is activated in the open state of the contactor, the initial target diagnostic process executed during normal startup is executed, and the control unit is activated The vehicle control unit according to claim 1, characterized by the above.

4. when the internal power supply circuit is activated in the open state of the contactor, the control unit invalidates the input from the throttle The vehicle control unit according to claim 1, characterized by the above.

5. when the internal power supply circuit is activated in the open state of the contactor, the control unit controls the motor drive circuit so as not to generate an induced voltage from the electric motor The vehicle control unit according to any one of claims 1 to 4, characterized by the above.

6. when the internal power supply circuit is activated in the open state of the contactor, the control unit controls the motor drive circuit to charge the first power source with the induced voltage generated from the electric motor The vehicle control unit according to any one of claims 1 to 4, characterized by the above.

7. Equipped with the vehicle control unit according to any one of claims 1 to 4 A traveling body characterized by the above.

8. Equipped with the vehicle control unit according to claim 5 A traveling body characterized by the above.

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