Vehicle control unit and running body

Abstract

To provide a vehicle control unit that can effectively prevent an inverter 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: an inverter circuit that drives an AC electric motor; a power supply for the inverter circuit; a control part that outputs a control signal for controlling rotation of the electric motor to the inverter circuit; and an internal power supply circuit having an enable terminal to which an input end of the inverter 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 activates the power supply for the inverter circuit and outputs a command signal for turning on switching elements of all arms in multiple phases to the inverter circuit.SELECTED DRAWING: Figure 1

Description

[[TECHNICAL FIELD]]

[0001] The present invention relates to a vehicle control unit used in a traveling body such as a two-wheeled vehicle using a motor as a drive source, and other traveling bodies such as a three-wheeled vehicle, and to the traveling body. [[BACKGROUND ART]]

[0002] In recent years, demand for two-wheeled vehicles with electric motors using a throttle as a speed adjustment mechanism has expanded. For example, Patent Document 1 describes an inverter circuit with enhanced functionality for motor control mounted on an electric two-wheeled vehicle. [[PRIOR ART DOCUMENTS]] [[PATENT DOCUMENTS]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2009-83710 [[SUMMARY OF THE INVENTION]] [[Problem to be Solved by the Invention]]

[0004] In an electric two-wheeled vehicle, an on-vehicle power supply can generally be charged with regenerative power from an electric motor that serves as a drive source. Due to such characteristics of electric two-wheeled vehicles, a driver may adjust their riding style to reduce power consumption or improve charging efficiency. For example, there are cases where a driver starts to descend a slope with the main switch and start switch of the electric two-wheeled vehicle kept off, and turns on the switches after the vehicle reaches a certain speed. That is, in order to reduce power consumption of the electric two-wheeled vehicle, the driver descends the slope without starting the electric motor of the electric two-wheeled vehicle. If an electric motor is rotated excessively while it is not running, a large induced voltage may be generated, potentially damaging the inverter circuit and causing the device to fail due to its voltage rating. To prevent this voltage rating failure, possible countermeasures include selecting a device with a high voltage rating to withstand the potential induced voltage, disconnecting the motor and short-circuiting the three phases, or changing the motor size or winding shape to reduce the induced voltage. However, when selecting high-voltage devices, especially drive devices, the higher the voltage, the higher the impedance, leading to higher costs. This results in a system that is not advantageous in terms of efficiency or cost, and undermines the advantages of electric motorcycles. Furthermore, while disconnecting the motor is a very effective method for protecting the inverter circuit, it increases the motor's heat generation and necessitates many additional components, such as contactors or other circuit breakers between the inverter and the motor, thus raising the system cost. Furthermore, if countermeasures are implemented on the motor side, it will be necessary to upgrade the magnets or increase the motor size, which will increase costs.

[0005] This invention has been made in view of these circumstances, and its purpose is to provide a vehicle control unit and a vehicle body that can effectively prevent damage to the inverter circuit when an electric motorcycle is driven uphill with the electric motor turned off. [Means for solving the problem]

[0006] To achieve this objective, the technical means according to the present invention is a vehicle control unit having at least the following configuration.

[0007] via contactor For motor driveA vehicle control unit connected to a power supply, comprising: an inverter circuit for driving an AC electric motor; a power supply for the inverter circuit for supplying power to the inverter circuit; a control unit for outputting a control signal to the inverter circuit for controlling the rotation of the electric motor; and an internal power supply circuit having an enable terminal to which the input terminal of the inverter circuit is connected, wherein the inverter circuit has an arm for one phase of AC formed by a series circuit of an upper switching element and a lower switching element, and is provided with a freewheeling diode connected in parallel to each switching element with the direction from the lower side to the upper side as the forward direction, and the vehicle control unit is configured such that a voltage induced when the electric motor rotates at a predetermined or higher rotational speed with the contactor open activates the internal power supply circuit, and when the internal power supply circuit is activated with the contactor open, the control unit activates the power supply for the inverter circuit and outputs a command signal to the inverter circuit to turn on the lower switching elements of all of the multiple phase arms.

[0008] Furthermore, in order to achieve the above objective, the technical means according to the present invention is a traveling body having at least the following configuration.

[0009] via contactor For motor driveA vehicle is provided with a vehicle control unit connected to a power supply, wherein the vehicle control unit comprises an inverter circuit for driving an AC electric motor, a power supply for the inverter circuit for supplying power to the inverter circuit, a control unit for outputting a control signal to the inverter circuit for controlling the rotation of the electric motor, and an internal power supply circuit having an enable terminal to which the input terminal of the inverter circuit is connected, wherein the inverter circuit has an arm for one phase of AC formed by a series circuit of an upper switching element and a lower switching element, and is provided with a freewheeling diode connected in parallel to each switching element with the direction from the lower side to the upper side as the forward direction, and the vehicle control unit is configured such that a voltage induced when the electric motor rotates at a predetermined or higher rotational speed with the contactor open activates the internal power supply circuit, and when the internal power supply circuit is activated with the contactor open, the control unit activates the power supply for the inverter circuit and outputs a command signal to the inverter circuit to turn on the lower switching elements of all of the multiple phase arms. [Effects of the Invention]

[0010] With these features, the present invention can effectively prevent damage to the inverter circuit when an electric motorcycle is driven uphill with the electric motor turned off. [Brief explanation of the drawing]

[0011] [Figure 1] This is a system configuration diagram of a vehicle control unit according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram showing the operation sequence of a vehicle control unit according to an embodiment of the present invention. [Modes for carrying out the invention]

[0012] The following describes an example of an embodiment of the vehicle control unit according to the present invention, based on the drawings. However, the following drawings are created for illustrative purposes, and in order to make them easier to understand, some components that are not necessary for the explanation may be intentionally omitted. Also, components may be intentionally shown larger or smaller for illustrative purposes, and the drawings do not represent an accurate scale. In the following description, the same reference numerals in different figures indicate parts with the same function, and redundant explanations in each figure will be omitted as appropriate.

[0013] <Embodiment> (System Configuration) Figure 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 motorcycle. In this embodiment, the vehicle control unit 1 is connected to a first power supply 2, which is a 96V lithium-ion battery and serves as a power supply for motor drive, and a second power supply 4, which is a 12V lead-acid battery and serves as a power supply for unit control.

[0014] The vehicle control unit 1 includes a series regulator 11 as an internal power supply circuit, a control unit 12 for driving and controlling the motor 3 by generating, for example, a PWM signal, an inverter circuit 13 including six power transistors as switching elements for driving the motor 3, and a power supply 14 for the inverter circuit.

[0015] The series regulator 11 has its enable terminal connected to the output of the main switch or key switch 16. When the main switch or key switch is operated, a constant voltage of about 5V is applied to the enable terminal, and the series regulator 11 starts up. The series regulator 11 also has the first power supply 2, which is voltage-divided and connected to its enable terminal via the contactor 21. This voltage division ratio is set taking into account the effect of the DC link capacitor so that the voltage value is appropriate for starting the series regulator 11 due to the induced voltage generated from the motor 3 during hill starts, as described later.

[0016] Signals from a main switch or key switch 16, and from a throttle 17 provided on a handlebar of the electric two-wheeled vehicle are input to the control unit 12. The control unit 12 generates, for example, PWM signals for driving circuits for normal motor control and charging control in accordance with an operation applied to the throttle 17 and an operation applied to a brake (not shown). In addition to this, the control unit 12 also executes circuit protection control, which will be described later.

[0017] The inverter circuit 13 has six power transistors serving as switching elements 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 MOSFETs. Although part of the representation by lead lines is omitted, three MOSFETs, namely an upper U-phase FET 131U, an upper V-phase FET 131V, and an upper W-phase FET 131W, which are connected to the first power supply 2 via the contactor 21, are arranged in the upper stage in the drawing. Three MOSFETs, namely a lower U-phase FET 132U, a lower V-phase FET 132V, and a lower W-phase FET 132W, which are installed, are arranged in the lower stage in the drawing. The source of the upper U-phase FET 131U is connected to the drain of the lower U-phase FET 132U, the source of the upper V-phase FET 131V is connected to the drain of the lower V-phase FET 132V, and the source of the upper W-phase FET 131W is connected to the drain of the lower W-phase FET 132W. Drive current is supplied to the U-phase, V-phase, and W-phase of the motor 3 from each of these connection nodes, respectively.

[0018] Each power transistor is provided with a freewheeling diode between the source and drain, whose forward direction is from the lower stage side to the upper stage side, in order to prevent the influence of back electromotive force generated when current is cut off due to current continuing to flow even after the switch is turned off. As the freewheeling diode, a fast recovery diode that is provided with measures for reducing reverse recovery time is used herein.

[0019] The inverter circuit 13 includes an inverter circuit power supply 14 so that the inverter circuit 13 can operate even when the contactor 21 is in an open state. Although illustration of wiring is omitted, the inverter circuit power supply 14 is configured to be supplied with electric power from the second power supply 4. The inverter circuit power supply 14 is activated by a signal from the control unit 12.

[0020] The control unit 12 of the vehicle control unit 1 also outputs a signal to the battery management system 15. In addition to performing thermal control on the first power supply 2, the battery management system 15 detects an abnormal state caused by overcurrent, and outputs a signal to the contactor 21 for disconnecting the vehicle control unit 1 from the first power supply 2. The battery management system 15 also performs monitoring, predictive calculation and the like for voltage, current, temperature, SOC and the like.

[0021] In order to use the battery safely and effectively, and to prevent damage to electronic devices, the vehicle control unit 1 fulfills important functions. For example, to reduce power consumption of an electric two-wheeled vehicle, when a driver performs an operation of temporarily turning off the main switch of the electric two-wheeled vehicle to eliminate power consumption while the electric two-wheeled vehicle is traveling on a slope, the battery management system 15 does not immediately turn off the vehicle control unit 1 when the vehicle speed is equal to or higher than a certain value even if the main switch is turned off, and prevents breakdown due to overvoltage of circuit devices by canceling back electromotive force through PWM control. This can be referred to as circuit protection control during slope travel. However, this circuit protection control during slope travel is possible only when the vehicle control unit 1 is operating; if the vehicle control unit 1 is not activated, breakdown due to overvoltage of the device cannot be prevented. A situation in which the electric two-wheeled vehicle travels while the vehicle control unit 1 is not activated can actually occur. This occurs when the driver starts the electric two-wheeled vehicle on a slope while the main switch of the electric two-wheeled vehicle, which is stopped on the slope, remains turned off. The vehicle control unit according to the embodiment of the present invention can effectively prevent breakdown due to overvoltage of devices even in such a situation. This will be described below.

[0022] (Action sequence) The operation sequence of a vehicle control unit according to an embodiment of the present invention will be described with reference to Figure 1. When the vehicle control unit 1, to which the first power supply 2 and the second power supply 4 are connected, is system off, the contactor 21 is open and the 5V output of the series regulator 11 is off. The series regulator 11 starts outputting when a voltage is input to the enable terminal. When the driver operates the key switch or main switch, the contactor is closed and the voltage of the second power supply 4 is input to the enable terminal, and the series regulator 11 starts up. This operation is the normal startup operation of the series regulator 11 and is called a normal startup.

[0023] Next, we will describe the emergency start, which is a feature of the present invention, specifically the start-up when starting on a slope. When an electric motorcycle is started to be ridden down a slope by its own weight without operating the key switch or main switch, the motor 3 mounted near the rear wheel of the electric motorcycle is forcibly rotated. This causes a change in the magnetic flux passing through the coil of the motor 3, generating an induced voltage. When a motor induced voltage is generated, a voltage is applied to the enable terminal of the series regulator 11 through the fast recovery diodes provided in the upper U-phase FET 131U, upper V-phase FET 131V, and upper W-phase FET 131W of the inverter circuit 13. For example, the voltage division ratio of the voltage divider resistors is adjusted so that a voltage sufficient to start the series regulator 11 is applied to the enable terminal when a voltage of a certain level or higher is generated, such as 30Vpeak at 3000rpm.

[0024] More specifically, the voltage applied to the series regulator 11 is adjusted so that the voltage division ratio is the same during normal startup and emergency startup. In other words, the voltage division ratio is adjusted so that the induced voltage when starting the series regulator 11 is less than or equal to the voltage of the drive power supply. This applied voltage value corresponds to the induced voltage of 30Vpeak at 3000rpm mentioned above.

[0025] When motor 3 rotates and approximately 4V is input to the enable terminal, the series regulator 11 starts up, and the control unit 12 also starts up. After that, the control unit 12 continues to operate using power from the second power supply 4. However, to prevent exceeding the voltage rating of the enable terminal of the series regulator 11, the control unit 12 disconnects the power supply line from the motor while it is operating.

[0026] The control unit 12 is activated by a method other than normal input, which is determined by the state of the contactor 21, the voltage monitor value of the first power supply 2, the motor speed, etc. In other words, it can be determined that it is an emergency start. The control unit 12, having determined that it is an emergency start, activates the power supply 14 for the inverter circuit.

[0027] When the inverter circuit power supply 14 is started, the vehicle control unit 1 begins control operation using PWM control. As a measure against device breakdown voltage failure, the vehicle control unit 1 turns on all of the lower stage U-phase FET 132U, lower stage V-phase FET 132V, and lower stage W-phase FET 132W to perform active short-circuit control for fail-safe purposes. This control allows current to flow using the lower stage power transistors so as not to exceed the element breakdown voltage, that is, it prevents the inverter circuit 13 from failing due to induced voltage from the motor 3. In addition, the vehicle control unit 1 prohibits torque control by throttle operation, which is performed during normal operation. Specifically, the control unit 12 disables the throttle input.

[0028] The operation sequences described above will now be explained as sequences for each system. Figure 2 is an explanatory diagram showing the operation sequence of a vehicle control unit according to an embodiment of the present invention, showing the vehicle state, the action that occurs, and the action in the control unit in a row.

[0029] In terms of the vehicle's state, the handlebars are initially unlocked and the main switch is off. Since the driver is about to start riding, the handlebar lock is naturally released. However, to avoid consuming power, the driver will start the electric motorcycle while it is stopped on a slope with the main switch still off.

[0030] As the rear wheel of the electric motorcycle rotates, motor 3 will eventually be forced to rotate at a predetermined speed or higher, such as 3000 rpm.

[0031] As the motor rotor rotates, the magnetic field of the magnets attached to the rotor induces electromagnetic induction in the motor's stator windings. This induced current generates an induced voltage, which is applied to the vehicle control unit 1. This induced voltage is basically a sine wave and is smoothed by the DC link capacitor after passing through the freewheeling diodes of the upper U-phase FET 131U, upper V-phase FET 131V, and upper W-phase FET 131W of the inverter circuit 13. This smoothed voltage is applied to the enable terminal of the series regulator 11. Upon receiving the enable command, the series regulator 11 is supplied with power from the 12V second power supply, which serves as the main power supply. Next, the control unit 12 starts up after performing the same processing as the initial target diagnostic process performed during normal startup, and the vehicle control unit 1 is turned on. The vehicle control unit 1 determines that it is an emergency startup after seeing that the contactor 21 is open, etc.

[0032] The vehicle control unit 1, having determined that an emergency start is occurring, activates the inverter circuit power supply 14. When the inverter circuit power supply 14 is activated, smart authentication is performed to verify whether the driver possesses the correct key.

[0033] Subsequently, the vehicle control unit 1 performs PWM control necessary for protecting the inverter circuit 13. Specifically, the vehicle control unit 1 turns on all of the lower U-phase FET 132U, lower V-phase FET 132V, and lower W-phase FET 132W to perform active short-circuit control for fail-safe purposes. This control allows current to flow using the lower power transistors to prevent exceeding the element's breakdown voltage, that is, it prevents the inverter circuit 13 from failing due to induced voltage from the motor 3. In addition, the vehicle control unit 1 disables torque control by throttle operation, which is performed during normal operation. Furthermore, the control unit 12 of the vehicle control unit 1 disables some functions, such as fault detection. On the other hand, the control unit 12 displays an indication that it is in correction mode.

[0034] In this embodiment, the motor speed is monitored every 5 seconds, and PWM control for circuit protection continues until the speed reaches zero. When the speed reaches zero, the vehicle control unit 1 sends a command signal to stop the power supply 14 for the inverter circuit. If the main switch is turned on before this, the system returns to the normal state, and this monitoring ceases.

[0035] As a circuit protection control, it is conceivable that in the event of an emergency startup, the series regulator 11 and the control unit 12 are activated, and the control unit 12, having determined that it is an emergency startup, closes the contactor 21 to operate the entire system. However, in that case, it is necessary to ensure sufficient consistency throughout the entire system, which would incur design changes and costs. The vehicle control unit according to the embodiment of the present invention is provided with a power supply 14 for the inverter circuit to which power from the second power supply is supplied, making it possible to use the conventional system with only minimal modifications.

[0036] Although the vehicle control unit and the vehicle equipped with the vehicle control unit according to the embodiments of the present invention have been described in detail above, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the gist of the present invention are also included. For example, as a circuit board, the internal power supply circuit was described using a series regulator as an example, but the internal power supply circuit may be configured with a DC-DC converter. Furthermore, although the vehicle was described as an electric two-wheeled vehicle, it can also be applied to electric three-wheeled vehicles such as electric three-wheeled motorcycles with two front wheels or electric scooters for commercial delivery with two rear wheels, and in the case of the type with two rear wheels, two motors may be provided. As described herein, the distinctive configuration of the vehicle control unit, which uses the induced voltage from the motor to start the system when the system is not running and then performs subsequent circuit protection processing, in other words, the distinctive configuration that enables effective circuit protection without arranging any hardware elements that are significantly different from those of previous systems, should be properly recognized. [Explanation of symbols]

[0037] 1. Vehicle control unit 11 Series Regulator (Internal Power Supply Circuit) 12 Control Unit 13 Inverter Circuit 131U Upper stage U phase FET 131V upper stage V phase FET 131W upper stage W-phase FET 132U Lower U phase FET 132V lower stage V phase FET 132W Lower W phase FET 15. Battery Management System 16 Main switches, key switches 17 Throttle 2 1st power supply 21 Contactor 3 motors 4 2nd power supply

Claims

1. A vehicle control unit connected to a motor drive power supply via a contactor, The aforementioned vehicle control unit is An inverter circuit that drives an AC electric motor, A power supply for the inverter circuit to supply power to the aforementioned inverter circuit, A control unit that outputs a control signal to the inverter circuit for controlling the rotation of the electric motor, The inverter circuit comprises an internal power supply circuit having an enable terminal to which the input terminal is connected, The inverter circuit comprises an arm for one phase of AC power formed by a series circuit of an upper switching element and a lower switching element, and is equipped with a freewheeling diode connected in parallel to each switching element with the direction from the lower to the upper side as the forward direction. The aforementioned vehicle control unit is The system is configured such that when the electric motor rotates at a predetermined or higher rotational speed while the contactor is open, the voltage induced activates the internal power supply circuit. When the internal power supply circuit is activated with the contactor open, the control unit activates the power supply for the inverter circuit and outputs a command signal to the inverter circuit to turn on the lower switching elements of all of the multiple phases of the arms. A vehicle control unit characterized by the following features.

2. The aforementioned vehicle control unit is When the internal power supply circuit is activated with the contactor open, the control unit stops the fault detection function. The vehicle control unit according to feature 1.

3. The vehicle control unit further includes a power supply for unit control, When the internal power supply circuit is started with the contactor open, the initial target diagnostic process that is normally performed during startup is executed, and the control unit starts up. The vehicle control unit according to feature 1.

4. When the internal power supply circuit is activated with the contactor open, the control unit disables the input from the throttle. The vehicle control unit according to feature 1.

5. A vehicle control unit according to any one of claims 1 to 4 A vehicle characterized by the following features.

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