Control device for electric vehicles

Abstract

To provide a control device of an electric vehicle which can perform auxiliary machine voltage control dealing with various low voltage components.SOLUTION: A control device of an electric vehicle includes: a travel ECU 10 which controls traveling of an electric vehicle; and an auxiliary machine ECU 20 which controls a voltage of an auxiliary machine battery 3 separately from the travel ECU 10. The auxiliary machine ECU 20 receives battery information indicating a state of the auxiliary machine battery 3 from the travel ECU 10, generates a voltage request signal which requests a DCDC converter 4 to provide a voltage based on the batter information, and transmits the voltage request signal to the travel ECU 10. The travel ECU 10 outputs a control signal to the DCDC converter 4 in response to the voltage request signal when receiving the voltage request signal from the auxiliary machine ECU 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for an electric vehicle.

Background Art

[0002] Patent Document 1 discloses performing travel control and auxiliary machine voltage control in the same ECU mounted on a vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there are various low-voltage components that operate at a low voltage, such as accessories of an electric vehicle. Therefore, in auxiliary machine voltage control, the control requirements become complicated due to the involvement of various low-voltage components. Further, in an OEM vehicle, when the ECU that executes travel control is manufactured by a contractor and the consignor designs the accessories, it is difficult to execute auxiliary machine voltage control in the ECU to cope with those various low-voltage components.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a control device for an electric vehicle that can execute auxiliary machine voltage control corresponding to various low-voltage components.

Means for Solving the Problems

[0006] The present invention relates to a control device for an electric vehicle, comprising: a driving control device for controlling the driving of the electric vehicle; and an auxiliary voltage control device, separate from the driving control device, for controlling the voltage of an auxiliary battery, wherein the auxiliary voltage control device receives battery information indicating the state of the auxiliary battery from the driving control device, generates a voltage request signal based on the battery information, requests a voltage from a converter that outputs voltage to the auxiliary battery, transmits the generated voltage request signal to the driving control device, and when the driving control device receives the voltage request signal from the auxiliary voltage control device, outputs a control signal to the converter corresponding to the voltage request signal.

[0007] In this configuration, the driving control and auxiliary voltage control of the electric vehicle are performed by separate control devices. This eliminates the need for the driving control device to perform auxiliary voltage control, allowing the auxiliary voltage control device to determine the minimum voltage and operating conditions and perform the auxiliary voltage control. Therefore, it is possible to perform auxiliary voltage control that is compatible with a variety of low-voltage components.

[0008] Furthermore, the auxiliary voltage control device may prohibit the transmission of the voltage request signal to the travel control device when predetermined prohibition conditions are met.

[0009] This configuration allows for the prohibition of transmitting voltage request signals as needed by setting prohibition conditions. This protects in-vehicle components that are affected by changes in the auxiliary battery voltage.

[0010] Furthermore, the auxiliary voltage control device may perform auxiliary voltage control to reduce the voltage of the auxiliary battery as needed, transmit the voltage request signal to the driving control device when performing the auxiliary voltage control, and the driving control device may transmit a prohibition request signal to the auxiliary voltage control device requesting the prohibition of the auxiliary voltage control if predetermined conditions are met.

[0011] This configuration allows for the disabling of auxiliary battery voltage control as needed. This protects on-board components that would be affected by a drop in auxiliary battery voltage. [Effects of the Invention]

[0012] In this invention, the driving control and auxiliary voltage control of the electric vehicle are performed by separate control devices. This eliminates the need for the driving control device to perform auxiliary voltage control, allowing the auxiliary voltage control device to determine the minimum voltage and operating conditions and perform auxiliary voltage control. Therefore, auxiliary voltage control can be performed in accordance with a variety of low-voltage components. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing a control device for an electric vehicle in an embodiment. [Modes for carrying out the invention]

[0014] The following describes in detail the control device for an electric vehicle in an embodiment of the present invention. However, the present invention is not limited to the embodiments described below.

[0015] Figure 1 is a schematic diagram showing a control device for an electric vehicle in an embodiment. The electric vehicle 1 comprises a motor, which is a power source, and a battery, which stores the power supplied to the motor. It generates driving force by supplying power from the battery to the motor and driving the motor, thereby enabling it to move. In this electric vehicle 1, the power output from the motor is transmitted to the wheels via a transaxle. For example, the electric vehicle 1 can be an electric vehicle or a hybrid vehicle. This battery is a high-voltage battery.

[0016] The electric vehicle 1 comprises a power control unit (hereinafter referred to as PCU) 2, an auxiliary battery 3, a driving ECU 10, and an auxiliary ECU 20.

[0017] Furthermore, the electric vehicle 1 is applicable to OEM vehicles. For example, a contractor manufactures a drive unit, and a client sells the electric vehicle 1 equipped with that drive unit. The drive unit includes an engine, motor, battery, transaxle, PCU2, and drive ECU10. In this case, the client can manufacture an auxiliary battery 3 and an auxiliary ECU20, and assemble them with the drive unit procured from the contractor to manufacture the electric vehicle 1. At that time, the client can design components other than the drive unit, such as low-voltage components that operate at low voltage, such as accessories. Therefore, in the electric vehicle 1, the drive ECU10 and the auxiliary ECU20 are configured as separate devices. In this embodiment, the electric vehicle 1 is an OEM vehicle, the PCU2 and drive ECU10 are manufactured by the contractor, and the auxiliary ECU20 is manufactured by the client.

[0018] Specifically, the PCU2 is a power conversion unit that includes a DC-DC converter 4 that supplies power to the auxiliary battery 3 and an inverter that drives the motor. The motor is electrically connected to the battery via the inverter. The inverter converts the battery's power and supplies it to the motor. The inverter has multiple switching elements, which are configured to perform switching operations.

[0019] The auxiliary battery 3 is a low-voltage battery that discharges and charges low-voltage power that allows the auxiliary equipment to operate. The auxiliary battery 3 is composed of a secondary battery, such as a lithium-ion battery or a lead-acid battery. The auxiliary battery 3 is electrically connected to the DC-DC converter 4 via a low-voltage line 31. Power output from the DC-DC converter 4 can be used to charge the auxiliary battery 3. The voltage of the auxiliary battery 3 is lower than the voltage of the battery included in the drive unit, for example, around 12V.

[0020] Auxiliary components are low-voltage parts that operate on power supplied from the low-voltage line 31 (approximately 12V). The DC-DC converter 4, the auxiliary battery 3, and the auxiliary components are electrically connected to the low-voltage line 31. Auxiliary components include, for example, a headlight system, audio equipment, various sensors, power window equipment, lighting equipment, wiper equipment, and navigation equipment.

[0021] The DC-DC converter 4 functions as an auxiliary DC-DC converter. The DC-DC converter 4 is also electrically connected to the battery via an inverter. The battery can supply high-voltage power to the DC-DC converter 4. The DC-DC converter 4 steps down the high-voltage DC voltage from the battery to a low-voltage DC voltage and supplies this stepped-down DC voltage to the auxiliary battery 3 and the auxiliary equipment. In other words, the DC-DC converter 4 converts the voltage of the DC power received from the battery into a voltage suitable for charging the auxiliary battery 3 and outputs this voltage to the auxiliary battery 3. The auxiliary battery 3 is charged by the voltage output from the DC-DC converter 4 to the auxiliary battery 3. The DC-DC converter 4 is electrically connected between the high-voltage power line and the low-voltage line 31, and can step down the power between the high-voltage power lines and supply it to the low-voltage line 31.

[0022] The traveling ECU 10 is an electronic control unit that controls the drive device of the electric vehicle 1. The traveling ECU 10 is a traveling control device that controls the traveling of the electric vehicle 1 and is a HEV-ECU. The traveling ECU 10 includes a processor and a memory. The processor consists of a CPU (Central Processing Unit) or the like. The memory is a main storage device and consists of a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The traveling ECU 10 loads the program stored in the storage unit into the working area of the memory (main storage device) and executes it, and controls each component through the execution of the program to realize a function that meets a predetermined purpose. The storage unit is composed of recording media such as an EPROM (Erasable Programmable ROM), a hard disk drive (Hard Disk Drive: HDD), and a removable medium. Examples of the removable medium include disk recording media such as a USB (Universal Serial Bus) memory, a CD (Compact Disc), a DVD (Digital Versatile Disc), and a BD (Blu-ray (registered trademark) Disc). The storage unit can store an operating system (Operating System: OS), various programs, various tables, various databases, and the like. Signals from various sensors are input to the traveling ECU 10. Then, the traveling ECU 10 executes various controls based on the signals input from various sensors.

[0023] The traveling ECU 10 has a traveling control unit 11 and an accessory DCDC control unit 12.

[0024] The traveling control unit 11 is a control unit that controls the drive device of the electric vehicle 1. The drive devices controlled by the traveling control unit 11 include an engine, a motor, a battery, a transaxle, and the inverter of the PCU2. The traveling control unit 11 is a control unit that executes the traveling control of the electric vehicle 1.

[0025] The auxiliary DC-DC control unit 12 is a control unit that controls the DC-DC converter 4 of the PCU 2. The auxiliary DC-DC control unit 12 outputs control signals to the DC-DC converter 4. The DC-DC converter 4 outputs a voltage to the low-voltage line 31 in response to the control signals from the auxiliary DC-DC control unit 12.

[0026] The driving ECU 10 receives signals from the auxiliary battery sensor 5. The auxiliary battery sensor 5 is a sensor for monitoring the status of the auxiliary battery 3. The auxiliary battery sensor 5 consists of a voltage sensor that detects the voltage of the auxiliary battery 3 (battery voltage), a current sensor that detects the input / output current of the auxiliary battery 3 (battery current), and a temperature sensor that detects the fluid temperature of the auxiliary battery 3 (battery fluid temperature). The voltage sensor detects the voltage of the auxiliary battery 3 and outputs its detection signal to the driving ECU 10. The current sensor detects the input / output current of the auxiliary battery 3 and outputs its detection signal to the driving ECU 10. The temperature sensor detects the fluid temperature of the auxiliary battery 3 and outputs its detection signal to the driving ECU 10. The driving ECU 10 then generates battery information indicating the status of the auxiliary battery 3 based on the signals input from the auxiliary battery sensor 5. The battery information includes the voltage, current, and fluid temperature of the auxiliary battery 3.

[0027] Furthermore, the driving ECU 10 transmits battery information to the auxiliary ECU 20. The driving ECU 10 and the auxiliary ECU 20 are connected in a way that allows them to send and receive information. The driving ECU 10 transmits a signal containing battery information to the auxiliary ECU 20 as a signal necessary for calculating the auxiliary voltage. In the electric vehicle 1, the signal necessary for calculating the target voltage of the auxiliary battery 3 is transmitted to the auxiliary ECU 20 via the driving ECU 10.

[0028] The Auxiliary ECU 20 is an electronic control unit that controls the voltage of the auxiliary battery 3. The hardware configuration of the Auxiliary ECU 20 is the same as that of the Drive ECU 10. The Auxiliary ECU 20 is an auxiliary control unit that performs auxiliary voltage control and is an OEM-ECU manufactured by the client. The Auxiliary ECU 20 controls the voltage of the auxiliary battery 3 using battery information received from the Drive ECU 10.

[0029] The auxiliary ECU 20 has an auxiliary voltage control unit 21.

[0030] The auxiliary voltage control unit 21 is a control unit that performs auxiliary voltage control. Auxiliary voltage control is a control that lowers the voltage of the auxiliary battery 3 below the normal level. This auxiliary voltage control is a control that improves the fuel efficiency of the electric vehicle 1 and lowers the voltage of the auxiliary battery 3 as needed. For example, auxiliary voltage control includes a control that lowers the voltage of the auxiliary battery 3 to the minimum necessary level when it is not needed.

[0031] The auxiliary voltage control unit 21 generates a voltage request signal to request voltage from the DCDC converter 4 based on battery information. The voltage request signal includes a target voltage value calculated from the battery information. The auxiliary voltage control unit 21 performs control to determine the minimum voltage of the auxiliary battery 3 and the operating conditions of low-voltage components. Based on these operating conditions and the minimum voltage, the target voltage included in the voltage request signal is determined. This minimum voltage is the lowest voltage that can be set as the voltage of the auxiliary battery 3 when performing auxiliary voltage control.

[0032] The auxiliary voltage control unit 21 then transmits the generated voltage request signal to the driving ECU 10. In other words, the auxiliary ECU 20 transmits a voltage request signal to the driving ECU 10 to control the voltage of the auxiliary battery 3.

[0033] When the drive ECU 10 receives a voltage request signal from the auxiliary ECU 20, it outputs a control signal corresponding to the voltage request signal to the DCDC converter 4. The DCDC converter 4 outputs a voltage corresponding to the control signal to the low-voltage line 31.

[0034] Furthermore, the drive ECU 10 can reject or prohibit voltage request signals from the auxiliary ECU 20 in order to protect the drive system.

[0035] For example, the driving ECU 10 sends a prohibition request signal to the auxiliary ECU 20 requesting the prohibition of auxiliary voltage control when certain conditions are met, such as when there is a need to protect the drive system. The need to protect the drive system includes situations where there is a high need to cool the battery or the PCU 2. In addition, a need to protect the drive system arises when the electric vehicle 1 is accelerating, when the radiator fan is running, when the battery (high-voltage battery) temperature is high, or when the coolant ON level of the PCU 2 is high. The driving ECU 10 performs a process to determine whether or not certain conditions, such as when there is a need to protect the drive system, are met.

[0036] When the auxiliary ECU 20 receives a prohibition request signal from the driving ECU 10, it prohibits the transmission of a voltage request signal to the driving ECU 10. The auxiliary ECU 20 determines whether a predetermined prohibition condition has been met by determining whether or not it has received a prohibition request signal. The auxiliary ECU 20 prohibits the transmission of a voltage request signal to the driving ECU 10 if the predetermined prohibition condition is met. The prohibition condition includes the case where a prohibition request signal has been received from the driving ECU 10.

[0037] Alternatively, the drive ECU 10 may be configured to allow the auxiliary ECU 20 to determine whether or not a drive protection request is arising, without the drive ECU 10 determining whether or not a drive protection request is arising. In this case, the drive ECU 10 is configured to transmit the information necessary to determine whether or not a drive protection request is arising to the auxiliary ECU 20. The auxiliary ECU 20 then determines whether or not the prohibition conditions are met by determining whether or not a drive protection request is arising. If the auxiliary ECU 20 determines that the prohibition conditions are met, it prohibits the transmission of a voltage request signal to the drive ECU 10.

[0038] Furthermore, the electric vehicle 1 is not limited to OEM vehicles. In other words, the electric vehicle 1 may have both the driving ECU 10 and the auxiliary ECU 20 manufactured by the same company. [Explanation of symbols]

[0039] 1. Electric Vehicle 2. Power Control Unit (PCU) 3. Auxiliary battery 4 DC-DC converters 5. Auxiliary battery sensor 10 Travel ECU 12 Auxiliary DC-DC Control Unit 20 Auxiliary ECU 21 Auxiliary Voltage Control Unit

Claims

1. A control device for electric vehicles, A driving control device that controls the movement of the electric vehicle, In addition to the aforementioned traction control device, there is an auxiliary voltage control device that controls the voltage of the auxiliary battery, Equipped with, The aforementioned driving control device receives a signal from an auxiliary battery sensor for monitoring the status of the auxiliary battery. The aforementioned travel control device is Control the converter that outputs voltage to the auxiliary battery, Based on the signal input from the auxiliary battery sensor, battery information indicating the status of the auxiliary battery is generated. The generated battery information is transmitted to the auxiliary voltage control device. The aforementioned auxiliary voltage control device is Using the battery information received from the aforementioned driving control device, the voltage of the auxiliary battery is controlled. The auxiliary voltage control is performed to lower the voltage of the auxiliary battery compared to normal. When performing the aforementioned auxiliary voltage control, a voltage request signal is generated that requests the converter to provide a voltage lower than normal based on the battery information received from the driving control device. The generated voltage request signal is transmitted to the travel control device. Furthermore, the aforementioned driving control device, When the voltage request signal is received from the auxiliary voltage control device, a control signal corresponding to the voltage request signal is output to the converter. When there is a request to protect the drive system in the electric vehicle, a prohibition request signal requesting the prohibition of the auxiliary voltage control is transmitted to the auxiliary voltage control device. Furthermore, when the auxiliary voltage control device receives the prohibition request signal from the travel control device, it prohibits the transmission of the voltage request signal to the travel control device. A control device for electric vehicles characterized by the following features.

2. The auxiliary battery sensor is A voltage sensor for detecting the voltage of the auxiliary battery, A current sensor for detecting the input and output current of the auxiliary battery, The auxiliary battery includes a temperature sensor for detecting the fluid temperature of the battery, The aforementioned battery information includes information on the voltage, current, and fluid temperature of the auxiliary battery. The voltage request signal includes a voltage value as the target voltage calculated from the battery information. The control device for an electric vehicle according to feature 1.

Images