Electric drive system for a battery-electric vehicle, and method for controlling an electric drive system

Abstract

The invention relates to an electric drive system for a battery-electric vehicle, comprising a battery, a frequency converter, an electric traction drive machine, and electric auxiliary consumers, which are electrically conductively connected to one another as components of an HV system, and comprising a control system for controlling and monitoring the components of the HV system, wherein the control system comprises a main controller which is designed to control control sequences in the electric drive system, such as a driving management process for controlling the traction drive machine, a charging management process for controlling a battery management system of the battery, and / or an energy management process for controlling auxiliary consumer control units of the auxiliary consumers, by controlling the components in the HV system; and the frequency converter comprises a frequency converter control unit which is designed to supply the traction drive machine with electric power from the battery on the basis of control commands of the control system in order to provide a torque specified by the control commands and / or a rotational speed specified by the control commands. The method according to the invention is characterized in that the main controller is integrated into the frequency converter control unit.

Description

[0001] Electric drive system for a battery-electric vehicle and method for controlling an electric drive system

[0002] The present invention relates to an electric drive system for a battery-electric vehicle and a method for controlling such an electric drive system.

[0003] An electric drive system for a battery-electric vehicle comprises a high-voltage system, hereinafter referred to as the HV system, in which various components are electrically interconnected, such as a battery, a frequency converter, an electric traction motor, and electrical auxiliary consumers. Electrical power from the battery supplies the traction motor and the electrical auxiliary consumers, with the frequency converter providing the electrical power from the battery to the electric traction motor in such a way that the electric traction motor generates a predetermined torque and / or a predetermined speed at its output to the wheels.

[0004] When an electrical voltage is referred to as high-voltage voltage (HV voltage) or a system as an HV system, this refers in particular to voltages of more than 60 volts or more than 200 volts. Specifically, this refers to a voltage as defined in ECE R100.

[0005] To control and monitor the components of the high-voltage (HV) system, electric drive systems for battery-electric vehicles include a control system with a main controller. This main controller is designed to manage control processes within the electric drive system by activating the components in the HV system. For example, driving management, charging management, and energy management are components of the main controller. In addition to this main controller, there are separate component controllers that receive control commands from the main controller and translate them into appropriate, immediate control of the respective component.

[0006] A typical system architecture of a conventional control system for an electric drive system in a battery-electric vehicle comprises a drive control unit, which can also be referred to as the main control unit, and numerous component control units. The drive control unit and the component control units communicate with each other via a fieldbus, for example, CAN. The drive control unit provides the main control, and the component control units each provide the direct control of their assigned components.

[0007] The control system typically also includes a safety controller, which is designed to monitor the functions of the main controller and, if necessary, intervene in the event of detected malfunctions in order to partially or completely shut down the main controller or components of the high-voltage system where a malfunction has been detected. The safety controller may, for example, include redundant safety controllers in addition to the control units of the main controller and the components, which also communicate with each other via a fieldbus, such as CAN.

[0008] A disadvantage of the known systems is that the number of required control units is high and a complex, distributed safety architecture must be implemented, whereby the executing and monitoring instances, i.e. the drive control unit and the component control units on the one hand and the safety control units on the other, are not synchronized, which leads to frequent malfunctions due to synchronization problems.

[0009] The present invention is based on the objective of providing an electric drive system for a battery-electric vehicle, the design of which is simplified, more cost-effective, and more reliable. This objective is achieved by an electric drive system with the features of claim 1 and a method with the features of claim 9. The dependent claims describe advantageous and particularly expedient embodiments of the invention.

[0010] An electric drive system for a battery-electric vehicle comprises a battery, a frequency converter, an electric traction motor, and electrical auxiliary consumers, all of which are electrically interconnected as components of a high-voltage (HV) system. The battery is a high-voltage battery that provides an electrical voltage of more than 60 V, and in particular more than 200 V.

[0011] Furthermore, the drive system includes a control system for controlling and monitoring the components of the high-voltage system. This control system comprises a main controller configured to manage control processes within the electric drive system by actuating the components in the high-voltage system. Such control processes include, for example, vehicle management for controlling the traction drive motor, charge management for controlling a battery management system, and / or energy management for controlling auxiliary control units. Thus, depending on incoming signals and commands, such as those from actuators operated by the driver and / or from a vehicle assistance system, the vehicle management system can control the traction drive motor so that it sets the desired speed and / or torque at its output shaft to propel or decelerate the vehicle.

[0012] The charging management system can control the battery management system based on commands, boundary conditions, or states to charge or discharge the battery. The energy management system can control the auxiliary consumer control units so that the auxiliary consumers perform the desired functions or complete the desired work.

[0013] The traction drive motor is controlled and its electrical power is supplied via the frequency converter. The frequency converter includes a frequency converter control unit, which is configured to supply the traction drive motor with electrical power from the battery, depending on control commands from the control system, in order to provide a torque and / or a speed specified by the control commands.

[0014] According to the invention, the main control is integrated into the frequency converter control unit.

[0015] The invention thus eliminates the need for the conventional drive control unit or main control unit, which includes the main control system. Furthermore, it simplifies the system architecture, particularly the safety architecture.

[0016] The main controller communicates, for example, via control lines with other control units in the control system, such as the auxiliary control units, a central electrical interface for the low-voltage power supply, and / or a charging control unit. Accordingly, the main controller is preferably connected to the other control units via such control lines. The high-voltage battery is specifically connected to the components of the high-voltage system via high-voltage lines.

[0017] As explained above, the control system preferably includes a safety controller configured to monitor the functions of the main controller and, in the event of a predefined detected malfunction, to partially or completely shut down the main controller and / or the components of the high-voltage system. Preferably, the safety controller is also integrated into the frequency converter control unit.

[0018] For example, the main control unit is configured to generate and transmit setpoints for the components of the high-voltage system based on detected drive states, vehicle states, vehicle environment states, and / or control signals from driver-operated actuators and / or a vehicle assistance system. The safety control unit is configured to detect these setpoints and compare them with setpoint ranges derived from predefined operating limits of the components. If the setpoint falls outside a corresponding predefined setpoint range, a malfunction is detected, allowing the safety control unit to partially or completely shut down the component and / or the main control unit accordingly.

[0019] Preferably, the frequency converter control unit comprises a multi-core processor with multiple cores that communicate with each other via internal communication lines. Thus, one core can be configured to execute the safety control, and a second core can be configured to execute the main control. Such a multi-core processor is also referred to as a multicore controller, and each core as a core. One core implements the safety functions, and the other the system functions.

[0020] Such a frequency converter control unit with a multi-core processor has the advantage that the safety computer, i.e., the safety controller that performs system monitoring, can directly access and measure the physical parameters of the frequency converter. This eliminates the need for a separate safety computer that would otherwise be required to determine and transmit the converter's actual values. The safety computer or safety controller can directly measure the setpoints and determine the operating limits for the application computer, i.e., the main controller. Within these operating limits, the setpoint generation for the system functions is specified.

[0021] Since both the safety computer, i.e. the safety controller, and the application computer, i.e. the main controller, are run on the same microcontroller, i.e. the same processor, information can be exchanged very quickly via the processor's internal communication lines, eliminating delays caused by fieldbus communication, such as CAN.

[0022] Since the main control is implemented directly on the frequency converter, the elimination of a separate drive control unit or main control unit leads to corresponding cost advantages.

[0023] To make the frequency converter compatible with conventional system architecture, an advantageous embodiment of the invention provides for a parameterizable frequency converter control unit. This allows the frequency converter to be operated as either a master or slave device, depending on the specific application, by activating a corresponding master or slave mode. When the frequency converter is operated in master mode, the main control is activated within its frequency converter control unit, thus eliminating the need for an external main control unit (drivetrain control unit) with these functions.The frequency converter or frequency converter control unit receives the driving requirements, i.e., control signals from actuators, for example, an accelerator pedal and brake pedal operated by the driver, and / or from a vehicle assistance system, calculates the permissible torque, adjusts the electrical power supply for the traction drive motor accordingly so that it generates the torque and / or speed depending on the driving requirements, and generates setpoints for the control units of the other components in the HV system, for example, the auxiliary consumer control units, the control units of the battery management system and / or the central electrical interface.

[0024] In slave mode, the frequency converter control unit only responds to the control commands of a higher-level control system and converts them into torque and / or speed of the traction drive machine.

[0025] In particular with such parameterizable frequency converter control units, but also through appropriate manufacturing and programming of the frequency converter control units, a preferred embodiment of the electric drive system is possible in which the components of the HV system comprise a second frequency converter and a second electric traction drive machine, the second frequency converter has a second frequency converter control unit which is configured to supply the second traction drive machine with electrical power from the battery in accordance with control commands in order to provide a torque and / or speed specified by the control commands, and the main control is configured as a master control unit to control the second frequency converter control unit as a slave control unit, that is, to generate the control commands for the second frequency converter unit.

[0026] According to a method according to the invention, the frequency converter control unit with the main control integrated in it controls control processes in the electrical drive system by controlling the components in the HV system, as previously explained.

[0027] The safety controller primarily monitors the function of the main controller and, in the event of a predefined detected malfunction, partially or completely shuts down the main controller and / or the components of the HV system.

[0028] The invention will be described below by way of example with reference to embodiments and the figures. The figures show:

[0029] Figure 1 shows an embodiment of an electric drive system according to the present invention;

[0030] Figure 2 shows the frequency converter control unit of the frequency converter from Figure 1;

[0031] Figure 3 shows an embodiment with two frequency converters, one of which is operated in master mode and the other in slave mode.

[0032] Figure 1 shows an embodiment of an electric drive system according to the invention for a battery-electric motor vehicle. The drive system comprises a battery 5 or HV battery 5, typically with a plurality of individual battery cells, a traction drive motor 2 that drives the drive wheels 29 of the motor vehicle, and a frequency converter 1 that adjusts the torque and / or speed of the traction drive motor 2, as components of an HV system 20.

[0033] The HV system 20 further comprises an electric braking resistor 3, a power distribution unit 4, electrical auxiliary consumers 12, 13, a charging controller 8, and a charging port 14. The power distribution unit 4, also called a PDU (Power Distribution Unit), distributes the electrical power from the battery 5 or from the traction motor 2 when it is operated as a generator to the various components in the HV system 20. The charging controller 8 controls the charging and discharging of the battery 5. The electric braking resistor 3 converts electrical power into heat when the traction motor 2 is operated as a generator and the electrical power generated by the traction motor 2 cannot be stored in the battery 5, for example, because it is fully charged.The high-voltage system 20 also incorporates an electrical system 24, which includes, for example, a low-voltage battery and provides the electrical power supply for the various vehicle components, such as the control devices and control units described below, via electrical system lines 26. The electrical system voltage is accordingly a low voltage, in particular with a maximum of 60 volts, for example 24 volts or 12 volts, so that a 60 V, 24 V or 12 V battery is provided accordingly.

[0034] The high-voltage voltage, for example of more than 200 volts, is transmitted in the HV system 20 via HV lines 25.

[0035] In the low-voltage system, which is supplied via the electrical on-board network 24, for example a central electrical interface 23 is provided, which distributes the electrical power of the on-board battery to the various electrical consumers.

[0036] The battery 5 comprises a battery management system 5.1, and the electrical auxiliary consumers 12 and 13 each comprise an auxiliary consumer control unit 12.1 and 13.1, respectively. The frequency converter 1 comprises a frequency converter control unit 1.1, a braking chopper 1.2, and a three-phase inverter 1.3. The three-phase inverter 1.3 provides the individual electrical phases for the traction drive motor 2, and the braking chopper 1.2 provides the electrical power for the electrical braking resistor 3. The auxiliary consumer control units 12.1 and 13.1 control the functions of the electrical auxiliary consumers 12 and 13, for example, an air compressor for a vehicle air system and / or a power steering pump.

[0037] The various control units and control devices and the battery management system 5.1 are part of a control system 21 and are connected to the frequency converter control unit 1.1 via control lines 10, which according to the invention comprises a main control 22, which is described below with reference to Figures 2 and 3.

[0038] Actuators 6, for example an accelerator pedal and / or brake pedal, which the driver can operate, and in particular a vehicle assistance system 7, are also connected to the frequency converter control unit 1.1 via control lines 10.

[0039] As can be seen particularly in Figure 2, the frequency converter control unit 1.1 comprises a first processor core 15 and a second processor core 16, which are connected to each other via internal communication lines 27. The first core 15 executes a safety control 28 and the second core 16 executes the main control 22, which includes corresponding applications such as a driving management 17, a charging management 18 and an energy management 19.

[0040] This allows information to be quickly exchanged internally between the safety controller 28, executed by the first Kem 15, and the main controller 22, executed by the second Kem 16. Furthermore, an additional external main controller can be eliminated.

[0041] However, as shown in Figures 1 and 2, the frequency converter control unit 1.1 is configurable so that it can be used as either a master or slave control unit in different drive systems. When the frequency converter control unit 1.1 is used as a master control unit, the safety controller 28 and the main controller 22 within the frequency converter control unit 1.1 are active. However, if an external, higher-level control device 9 with a main controller is provided, which is connected to the frequency converter control unit 1.1 and the actuators 6 and the vehicle assistance system 7 via control lines numbered 11 in Figures 1 and 2, then the safety controller 28 and the main controller 22 are inactive, and the frequency converter control unit 1.1 is inactive.1 merely implements commands from the higher-level control device 9 to supply the traction drive machine 2 with electrical power, resulting in the desired torque and / or speed.

[0042] Figure 3 shows an embodiment in which two frequency converters 1 designed according to the invention are jointly integrated into an electrical drive system according to the invention for a battery-electric vehicle. The frequency converter 1 described above can be referred to as the first frequency converter 1, and the second frequency converter is designated by reference numeral T. Both frequency converters 1, T have the same construction, for which reference is made to the preceding description. Each frequency converter 1, T supplies a separate electric traction drive motor, i.e., a first electric traction drive motor 2 and a second electric traction drive motor 2', with electrical power. The first electric traction drive motor 2 drives first drive wheels 29, and the second electric traction drive motor 2' drives second drive wheels 29'.The first electrical frequency converter 1 has a first braking unit 1.2 connected to a first electrical braking resistor 3, and a first three-phase inverter 1.3 that provides the electrical phases for the first traction drive machine 2. The second frequency converter T has, accordingly, a second braking unit 1.2' for a second electrical braking resistor 3', and a second three-phase inverter 1.3' that provides the electrical phases for the second traction drive machine 2'.

[0043] The second frequency converter control unit 1.T of the second frequency converter T also comprises two cores 15', 16', which are internally connected to each other via communication lines 27'. However, no safety control is activated on the first core 15' of the second frequency converter control unit 1.T, and no main control is activated on the second core 16' of the second frequency converter control unit 1.1'. Instead, the second frequency converter control unit 1.1' receives control commands via a control line 10 from the first frequency converter control unit 1.1 of the first frequency converter 1, which operates as the master control unit, whereas the second frequency converter control unit 1.1' operates as the slave control unit.

[0044] Accordingly, the safety controller 28 is activated on the first core 15 of the first frequency converter control unit 1.1, and the main controller 22 with the drive management 17, the charging management 18 and the energy management 19 is activated on the second core 16 of the first frequency converter control unit 1.1. Reference numeral list

[0045] 1 frequency converter

[0046] T second frequency converter

[0047] 1.1 Frequency converter control unit

[0048] 1.1' second frequency converter control unit 1.2 brake gradient

[0049] 1.2' second brake actuator

[0050] 1.3 Three-phase inverters

[0051] 1.3' second three-phase inverter

[0052] 2 Traction drive machine

[0053] 2' second traction drive machine

[0054] 3 electric braking resistor

[0055] 3' second electric braking resistor 4 power distribution unit

[0056] 5 batteries

[0057] 5.1 Battery Management System

[0058] 6 actuators

[0059] 7 Vehicle assistance systems

[0060] 8 Charging control

[0061] 9. Higher-level control device

[0062] 10 Control line

[0063] 11 Control line

[0064] 12 electrical auxiliary consumers

[0065] 12.1 Auxiliary consumer control unit

[0066] 13 electrical auxiliary consumers

[0067] 13.1 Auxiliary consumer control unit

[0068] 14 charging ports

[0069] 15 first core

[0070] 15' first core

[0071] 16 second core

[0072] 16' second Kem17 driving management

[0073] 18 Charging Management

[0074] 19 Energy Management

[0075] 20 HV system

[0076] 21 Tax system

[0077] 22 Main control

[0078] 23 central electrical interface 24 electrical on-board network

[0079] 25 HV line

[0080] 26 On-board power supply

[0081] 27 Communications Management

[0082] 27' Communications line

[0083] 28 Safety control

[0084] 29 drive wheel

[0085] 29' drive wheel

Claims

Patent claims 1. Electric drive system for a battery-electric vehicle with a battery (5), a frequency converter (1), an electric traction drive machine (2) and electrical auxiliary consumers (12, 13) which are electrically connected to each other as components of an HV system (20); with a control system (21) for controlling and monitoring the components of the HV system (20), wherein the control system (21) comprises a main control unit (22) which is configured to control control processes in the electric drive system by controlling the components in the HV system (20), such as a driving management unit (17) for controlling the traction drive motor (2), a charging management unit (18) for controlling a battery management system (5.1) of the battery (5) and / or an energy management unit (19) for controlling auxiliary consumer control units (12.1, 13.1) of the auxiliary consumers (12, 13); and the frequency converter (1) comprises a frequency converter control unit (1.1) which is configured to supply the traction drive machine (2) with electrical power from the battery (5) depending on control commands from the control system (21) to provide a torque and / or a speed specified by the control commands; characterized by the fact that the main control (22) is integrated into the frequency converter control unit (1.1).

2. Electric drive system according to claim 1, characterized in that the main control (22) is connected via control lines (10) to other control units in the control system (21), such as the auxiliary consumer control units (12.1, 13.1), a central electrical interface (23) for low-voltage power supply and / or a control unit of the charging control (8), and the battery (5) is connected via HV lines (25) to the components of the HV system (20).

3. Electric drive system according to one of claims 1 or 2, characterized in that the control system (21) comprises a safety controller (28) which is configured to monitor the functions of the main controller (22) and, in the event of a predefined detected malfunction, to partially or completely shut down the main controller (22) and / or the components of the HV system (20), wherein the safety controller (28) is also integrated into the frequency converter control unit (1.1).

4. Electric drive system according to claim 3, characterized in that the main control (22) is configured to generate and transmit setpoints for the components of the HV system (20) depending on detected drive system states, vehicle states, vehicle environment states and / or control signals from actuators (6) that can be operated by a driver and / or from a vehicle assistance system (7), and the safety control (28) is configured to detect the setpoints and compare them with setpoint ranges derived from predetermined operating limits of the components, and, if the setpoint is outside an associated setpoint range, to detect a malfunction.

5. An electric drive system according to claim 3 or claim 4, characterized in that the frequency converter control unit (1.1) comprises a multi-core processor with a plurality of cores (15, 16), a first core (15) is configured to execute the safety control (28), a second core (16) is configured to execute the main control (22), and the multi-core processor comprises internal communication lines (27) for communication between the cores (15, 16).

6. An electric drive system according to claims 4 and 5, characterized in that the safety control (28) is configured to read the setpoints via the internal communication lines (27).

7. Electric drive system according to one of claims 1 to 6, characterized in that the components of the HV system (20) comprise a second frequency converter (T) and a second electric traction drive machine (2'), the second frequency converter (T) comprises a second frequency converter control unit (1.T) which is configured, depending on control commands of the control system (21), to supply the second traction drive machine (2') with electrical power from the battery (5) to provide a torque and / or a speed specified by the control commands, and the main control (22) is configured as a master control unit to control the second frequency converter control unit (1.T) as a slave control unit.

8. Electric drive system according to one of claims 1 to 7, characterized in that the frequency converter control unit (1.1) is parameterizable and can be used selectively as a master control unit and slave control unit by activating and deactivating the main control (22).

9. A method for controlling an electric drive system according to any one of claims 1 to 8, characterized in that the frequency converter control unit (1.1) with the main control unit (22) integrated therein controls control sequences in the electric drive system by controlling the components in the HV system (20).

10. A method according to claim 9 for controlling an electric drive system according to any one of claims 3 to 8, characterized in that the safety control unit (28) monitors the functions of the main control unit (22) and, in the event of a predefined detected malfunction, partially or completely shuts down the main control unit (22) and / or components of the HV system (20).

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