Control unit and motor drive system for electric vehicles, and electric vehicles

Abstract

Provided is a control unit for an electrically driven vehicle, in which thermal effects on a control board and the like is reduced, and heat dissipation is satisfactorily performed. A control unit (20) for an electrically driven vehicle receives an operation signal and signals from various sensors, and outputs control signals for left and right inverters that drive left and right motors connected to left and right wheels, respectively. The control unit (20) includes, in a box (21), a first interface board (25) on which at least an interface with a large amount of heat generation is mounted, a second interface board (26) on which an interface with a smaller amount of heat generation than the interface mounted on the first interface board is mounted, and a control board (24) for generating a control signal. The first interface board (25) is disposed higher than the second interface board (26) and the control board (24) in the box (21).

Description

Technical Field

[0001] The present invention relates to a control unit and a motor drive device for an electric vehicle such as a dump truck, and an electric vehicle equipped with the same.

Background Art

[0002] As a vehicle such as a dump truck used in a mine or the like, an electric vehicle adopting an electric drive system for a drive system is known.

[0003]

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Electric vehicles have a controller that receives input signals from various sensors, such as accelerator pedals, brake pedals, and temperature sensors, and outputs control signals to control the speed of the motors connected to the drive wheels. It is conceivable to house multiple circuit boards that make up the controller in a box and unitize them. However, depending on the arrangement of the circuit boards, the control board may be affected by heat from other boards, which could impact the control characteristics.

[0006] In the "electrically driven vehicle" described in Patent Document 1, neither the integration of the controller into a single unit nor heat dissipation within the unit is considered.

[0007] The present invention aims to reduce thermal influence on control boards and other components in a control unit for an electric vehicle, and to improve heat dissipation. [Means for solving the problem]

[0008] To give an example of the "control unit for electric vehicles" of the present invention that solves the above problems, A control unit for an electric vehicle that receives operation signals and signals from various sensors and outputs control signals for left and right inverters that drive left and right motors connected to the left and right wheels, respectively, comprises a first interface board mounted on an interface that generates at least a large amount of heat, a second interface board mounted on an interface that generates less heat than the interface mounted on the first interface board, and a control board that generates control signals, wherein the first interface board is positioned above the second interface board and the control board.

[0009] Furthermore, to give an example of the "motor drive device for electric vehicles" of the present invention, A motor drive system for an electric vehicle that receives AC power from a generator and outputs drive signals for left and right motors connected to the left and right wheels, respectively, comprising: a rectifier unit that converts AC power from the generator to DC; a left motor inverter unit and a right motor inverter unit that create drive signals for the left and right motors, respectively; and a control unit that supplies control signals to the left motor inverter unit and the right motor inverter unit, wherein the control unit comprises a first interface board mounted on an interface that generates at least a large amount of heat, a second interface board mounted on an interface that generates less heat than the interface mounted on the first interface board, and a control board that generates control signals, wherein the first interface board is positioned above the second interface board and the control board. [Effects of the Invention]

[0010] According to the present invention, by placing the interface board equipped with a heat-generating interface at the top of the control unit's enclosure, the thermal impact on other boards can be reduced, and heat dissipation can be improved.

[0011] Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view of the dump truck of Example 1. [Figure 2A] This is a cross-sectional view of section AA' in Figure 1, taken from the front. [Figure 2B] This is a cross-sectional view of the BB' section in Figure 1, taken from the back. [Figure 3] This is a block diagram of the power system of the dump truck in Example 1. [Figure 4] This is a schematic block diagram of the electrical system of the dump truck of Example 1, including the circuit board layout within the control unit. [Figure 5] It is a block configuration diagram of the signal system of the dump truck in the first embodiment. [Figure 6] It is a perspective view of the control unit in the first embodiment. [Figure 7] It is a perspective view of another control unit in the first embodiment. [Figure 8] It is an explanatory diagram of a temperature sensor circuit using a thermistor. [Figure 9] It is a front view of the motor drive device in the second embodiment.

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not to be construed as being limited to the description of the embodiments shown below. Those skilled in the art can easily understand that the specific configuration can be changed without departing from the spirit or gist of the present invention. In each of the drawings for explaining the embodiments, the same components may be given the same names and reference numerals as much as possible, and the repeated description thereof may be omitted.

Embodiments

[0014] In this embodiment, the present invention is applied to a dump truck as an electric vehicle. FIG. 1 is a side view of the dump truck in the first embodiment, FIG. 2A is a sectional view of the A-A' section of FIG. 1 as seen from the front, and FIG. 2B is a sectional view of the B-B' section of FIG. 1 as seen from the back. Further, FIG. 3 is a block configuration diagram of the power system of the dump truck.

[0015] On the vehicle body 2 of the dump truck 1, left and right front wheels 6L and 6R are attached to the front side, and left and right rear wheels 7L and 7R are attached to the rear side. A cab (driver's cab) 5 is provided on the front side of the vehicle body 2, and the driver can enter the cab 5 from the deck portion 2A in front of the vehicle body 2. A control cabinet 8 is provided beside the cab 5, and a motor drive device 9 described later is accommodated therein. On the upper side of the rear part of the vehicle body 2, a loading platform 3 for loading goods such as ore is provided so as to be tiltable, and by tilting the loading platform 3 with the lifting cylinder 4, goods such as ore loaded on the loading platform 3 can be discharged.

[0016] As shown in the cross-sectional view seen from the rear side of FIG. 2B, left and right rear wheels 7L and 7R are respectively attached with a left motor 11L and a right motor 11R. As shown in the cross-sectional view seen from the front side of FIG. 2A, a cab 5 is provided above the left and right front wheels 6L and 6R, and a control cabinet 8 and a brake resistor 18 are provided beside it. The control cabinet 8 houses a control unit 20, a right motor inverter unit 12R, a left motor inverter unit 12L, etc. described later, and constitutes the motor drive device 9.

[0017] FIG. 3 shows a schematic configuration diagram of the power system of the dump truck 1. This power system is a system in which a diesel engine drives a generator to generate AC power, converts the generated AC power into DC power, and drives an induction motor with an inverter.

[0018] When the dump truck 1 is accelerating, the diesel engine 17 drives the generator 15 to generate three-phase AC power, and the AC power is converted into DC power by a rectifier (converter) 13 and a capacitor 14. Then, the DC power is supplied to the right motor inverter 12R and the left motor inverter 12L. Each inverter is connected to a right motor 11R and a left motor 11L which are induction motors, and by driving the induction motors with the inverters, the left and right rear wheels 7L and 7R are rotated to move the dump truck forward or backward.

[0019] When the dump truck 1 is decelerating, the induction motor is used as a generator to convert the kinetic energy of the vehicle into electrical energy. A brake resistor 18 is connected to the DC circuit via a chopper 19. If the DC voltage exceeds a specified value, the chopper 19 is activated and connected to the brake resistor 18, causing the brake resistor 18 to dissipate this electrical energy as heat. This then decelerates the dump truck 1.

[0020] Here, the DC voltage of the DC circuit is controlled by changing the rotational speed of the engine 17, and the inverter 12L for the left motor and the inverter 12R for the right motor are controlled by the control unit 20. Furthermore, the rectifier 13, inverters 12L and 12R, control unit 20, etc. constitute the motor drive unit 9.

[0021] Figure 4 shows a schematic block diagram of the electrical system of the dump truck, including the circuit board layout within the control unit 20. As previously explained, the engine 17 drives the generator 15 to generate AC power, which is converted to DC power by the rectifier 13, and the left and right motor inverters 12L and 12R drive the left and right motors 11L and 11R, respectively. The control unit 20 includes a control board 24, a left motor control board 22L, a right motor control board 22R, and interface boards 25 and 26 for multiple sensors. Details of the control unit 20 will be described later. The left and right motors 11L and 11R are equipped with speed sensors and temperature sensors, and the left and right motor inverters 12L and 12R are equipped with current sensors. Detection signals from the speed sensors, temperature sensors, and current sensors are input to the control unit 20, and based on these detection signals and signals from the control board 24, the left and right motor control boards 22L and 22R create control signals (such as gate pulses) for the inverters. These signals are then supplied to the left and right motor inverters 12L and 12R that drive the left and right motors 11L and 11R.

[0022] Figure 5 shows a block diagram of the signal system of the dump truck in this embodiment. The control unit 20 receives operation signals such as accelerator and brake signals, as well as detection signals from speed sensors, various temperature sensors, and a water level sensor that detects the coolant level. Temperature sensors include temperature sensors that detect the temperatures of the left and right motors 11L and 11R, temperature sensors that detect the temperatures of the left and right inverters 12L and 12R, temperature sensors that detect the temperature of the coolant, temperature sensors that detect the temperature of the brake resistor 18, and temperature sensors that detect the temperature inside the control unit 20.

[0023] Furthermore, the dump truck has a display unit 32 in the driver's cab 5 that displays driving conditions such as speed and alarms when an abnormality is detected, and is also equipped with various auxiliary devices 31 such as cooling fans. Cooling fans are installed as needed in places that generate heat, such as the left and right motors 11L, 11R, brake resistors 18, and inside the control cabinet 8. The control board 24 is equipped with a microcontroller and includes, for example, a torque command creation unit and a speed command creation unit that create control signals to be supplied to the left and right motor control boards, an abnormality detection unit that performs abnormality detection from detection signals, a display signal creation unit that creates display signals to be supplied to the display unit, and a fan control signal creation unit that creates control signals for the cooling fan, which is an auxiliary device.

[0024] Here, we will explain a temperature sensor using a thermistor. Figure 8 shows an example of a temperature detection circuit using a thermistor. A DC power supply Vin is connected to the series circuit of thermistor Rt and resistor R1, supplying a detection current I. Since the resistance value of the thermistor changes according to the temperature, the temperature can be detected by detecting the voltage Vout at the connection point of thermistor Rt and resistor R1. In this way, temperature detection using a thermistor requires supplying a detection current I. It is necessary to do so, and the interface to which a thermistor is connected as a detection element will generate heat due to the detection current. Furthermore, the heat generated on the interface board on which the thermistor interface is mounted may have a thermal effect on other boards such as the control board, potentially causing unstable characteristics. Thermistors are also used in water level sensors.

[0025] One characteristic configuration of this embodiment is that, as shown in Figure 6, a first sensor interface board 25 equipped with a heat-generating interface such as a temperature sensor is provided inside the box 21, and a second sensor interface board 26 equipped with a low-heat-generating interface such as a speed sensor is provided, and the arrangement of the first interface board and the second interface board is carefully considered.

[0026] Figure 6 shows an example of a control unit 20 incorporating various circuit boards. A first sensor interface board 25, equipped with a heat-generating interface such as a temperature sensor, is placed on the top of the enclosure 21. Below the first sensor interface board 25, a control board 24 and a second sensor interface board 26, equipped with a low-heat-generating interface such as a speed sensor, are placed. In the example shown, the second sensor interface board 26 is placed below the control board 24. Here, a heat-generating interface is an interface that supplies detection current to the connected sensor, such as an interface to which a thermistor, which is a temperature sensor, is connected. In addition, ventilation holes 28 are provided on the top of the side panel of the enclosure 21.

[0027] By placing the first sensor interface board 25, which is equipped with a heat-generating interface, at the top of the enclosure 1, the heat generated from the first sensor interface board 25 is directed towards the top of the enclosure 21 and dissipated through vents 28, etc., thereby reducing the thermal impact on other boards such as the control board.

[0028] Another characteristic configuration of this embodiment is that, as shown in Figure 6, the left motor control board 22L and the right motor control board 22R are arranged symmetrically on the left and right sides of the box body 21, respectively. Specifically, the left motor control board 22L and the right motor control board 22R are arranged symmetrically with respect to the center line of the box body 21. By arranging the left motor control board 22L and the right motor control board 22R symmetrically, temperature imbalances can be reduced, and the deviation in the characteristics of the left and right motor controls due to temperature changes can be reduced.

[0029] Although not shown in the diagram, a cooling fan may be provided to supply cooling air into the enclosure 21 as needed. Alternatively, a temperature sensor may be provided to detect the temperature inside the enclosure 21, and the cooling fan may be controlled according to the temperature detected by the temperature sensor.

[0030] Figure 7 shows a modified version of the control unit 20. In this modified version, multiple ventilation holes 28 are provided on the top surface (top plate) of the box body 21. By providing multiple ventilation holes 28 on the top surface of the box body 21, the heat generated by the first sensor interface board 25 can be dissipated effectively.

[0031] According to this embodiment, in the control unit of an electric drive vehicle, by placing the first sensor interface board, which is equipped with an interface that generates a lot of heat, at the top of the enclosure above the second sensor interface board and the control board, which are equipped with interfaces that generate less heat than the interface mounted on the first sensor interface board, the heat generated from the first sensor interface board is directed towards the top of the enclosure and dissipated through vents, etc., thereby reducing the thermal impact on other boards such as the control board.

[0032] Furthermore, by symmetrically arranging the left motor control board and the right motor control board on the left and right sides of the enclosure, temperature imbalances can be reduced, thereby minimizing the deviation in the characteristics of the left and right motor controls due to temperature changes. [Examples]

[0033] Figure 9 shows a motor drive device according to Embodiment 2 of the present invention. The motor drive device of this embodiment is a motor drive device for an electric vehicle that receives AC power from a generator and outputs drive signals for left and right motors connected to the left and right wheels, respectively, and is an aggregate of the various units that make up the motor drive device.

[0034] As shown in Figure 9, the motor drive unit consists of a left motor inverter unit 12L and a right motor inverter unit 12R, which generate drive signals for the left and right motors respectively; a rectifier unit 13, which converts AC power from the generator to DC power; and a control unit 20 of Embodiment 1, which supplies control signals to the left motor inverter unit and the right motor inverter unit. Each unit constituting the motor control device 9 is housed in the control cabinet 8 of the dump truck, as shown in Figure 2A.

[0035] Although the above embodiments describe the application of the present invention to a dump truck, the present invention can also be used in other electric-powered vehicles.

[0036] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. In addition, it is possible to add, delete, or replace some of the configurations in each embodiment with other configurations. [Explanation of Symbols]

[0037] 1 Dump truck 2 car bodies 2A Deck Section 3. Cargo bed 4. Relief cylinder 5. Cabin (driver's cab) 6L,6R front wheel 7L,7R rear wheel 8 Control Cabinets 9. Motor drive unit 11L Left Motor 11R Right Motor 12L left motor inverter 12R Right Motor Inverter 13. Rectifier (Converter) 14 Capacitors 15 Generators 17 Engine 18 Brake Resistor 19 Choppa 20 Control Units 21 Box body 22L Left Motor Control Board 22R Right Motor Control Board 24 Control board 25 First sensor interface board 26. Second sensor interface board 28 Ventilation holes 31 Auxiliary equipment 32 Display section

Claims

1. A control unit for an electric vehicle that receives operating signals and signals from various sensors, and outputs control signals for left and right inverters that drive the left and right motors connected to the left and right wheels, respectively. A first interface board equipped with an interface that generates heat during use, a second interface board equipped with an interface that generates less heat than the interface mounted on the first interface board, and a control board that generates control signals. The system comprises the first interface board, the second interface board, and a housing for the control board, Ventilation openings are provided on the upper part of the left and right side walls of the box, or on the top surface of the box. A control unit for an electric vehicle, wherein the first interface board is positioned above the second interface board and the control board in the enclosure.

2. In the control unit for an electric vehicle according to claim 1, The interface mounted on the first interface board is a control unit for an electric vehicle that supplies current to the connected sensor.

3. In the control unit for an electric vehicle according to claim 2, The interface mounted on the first interface board is an interface connected to a temperature sensor, and is part of the control unit for an electric vehicle.

4. In the control unit for an electric vehicle according to claim 3, The aforementioned temperature sensor is a thermistor, in the control unit of an electric vehicle.

5. In the control unit for an electric vehicle according to claim 1, further, A control unit for an electric vehicle, wherein a left motor control board and a right motor control board are evenly arranged on the left and right sides of the aforementioned box-shaped structure.

6. A motor drive device for an electric vehicle that receives AC power from a generator and outputs drive signals for left and right motors connected to the left and right wheels, respectively, A rectifier unit that converts AC power from the generator into DC power, A left motor inverter unit and a right motor inverter unit, which generate drive signals for the left and right motors respectively, A control unit that supplies control signals to the left motor inverter unit and the right motor inverter unit, Equipped with, The control unit includes a first interface board equipped with an interface that generates heat during use, a second interface board equipped with an interface that generates less heat than the interface mounted on the first interface board, and a control board that generates control signals. The system comprises the first interface board, the second interface board, and a housing for the control board, Ventilation openings are provided on the upper part of the left and right side walls of the box, or on the top surface of the box. A motor drive device for an electric vehicle, wherein the first interface board is positioned above the second interface board and the control board in the housing.

7. In the motor drive device for an electric vehicle according to Claim 6, The interface mounted on the first interface board of the control unit supplies current to the connected sensor, in a motor drive device for an electric vehicle.

8. In the motor drive device for an electric vehicle according to claim 7, The interface mounted on the first interface board of the control unit is an interface connected to a thermistor, in a motor drive device for an electric vehicle.

9. In the motor drive device for an electric vehicle according to claim 6, further, A motor drive device for an electric vehicle, wherein a left motor control board and a right motor control board are evenly arranged on the left and right sides of the box-shaped body of the control unit.

10. In the motor drive device for an electric vehicle according to claim 6, A motor drive system for an electric vehicle, wherein the rectifier unit, the left motor inverter unit, the right motor inverter unit, and the control unit are housed in the control cabinet of the electric vehicle.

11. An electric drive vehicle comprising left and right motors connected to the left and right wheels respectively, and the motor drive device described in Claim 6.

12. In the electric drive vehicle according to claim 11, further, A generator that produces alternating current, An electric vehicle comprising an engine that drives the aforementioned generator.

13. In the electric drive vehicle according to claim 11, The aforementioned electric-powered vehicle is an electric-powered dump truck.

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