DE102014204803A1 - Control strategy for an electric machine in a vehicle - Google Patents

Abstract

A system and method for controlling an electric vehicle are provided. The electric vehicle includes at least one control device that is configured to determine an overvoltage fault when the voltage of an electrical machine exceeds an overvoltage threshold. In response to the overvoltage fault, the electrical machine and a variable voltage converter (VVC) are deactivated. If it is determined that the voltage of the electrical machine has dropped to at least one safety threshold that is lower than the overvoltage threshold, the controller is configured to set the VVC to a restricted operating mode. If it is determined that the voltage of the electrical machine has dropped to at least a third threshold that is lower than the safety threshold and the overvoltage threshold, the controller is configured to reactivate the electrical machine and to set the VVC to a normal operating mode. The restricted operating mode allows the vehicle to maintain vehicle propulsion during the driving cycle while the electrical machine is recovering from a temporary condition that is causing the overvoltage fault.

Description

The present disclosure relates to a system for controlling an electric machine in an electric vehicle.

Battery electric vehicles (BEVs) include a traction battery that is rechargeable from an external electrical power source and drives the electric machine. Hybrid electric vehicles (HEVs) include a built-in internal combustion engine, one or more electric machines, and a traction battery that at least partially powers the electric machine. Plug-in hybrid electric vehicles (PHEVs) are similar to HEVs, but the traction battery in a PHEV can be charged from an external electrical power source. These vehicles are examples of vehicles that can be at least partially powered by an electric machine.

If a failure of a component is detected that is necessary for the electric drive, then several actions may be required in these vehicles to ensure the safety of the vehicle occupants. Since shutdown of the entire vehicle may be undesirable, limited operating strategy (LOS) modes may be implemented to allow the operator of the vehicle to continue driving while disabling individual components.

In accordance with one or more embodiments of the present disclosure, a method of controlling a hybrid electric vehicle is provided. The method includes deactivating an electric machine and a variable voltage converter (VVC) when the voltage of an electric machine exceeds an overvoltage threshold. If it is determined that the voltage of the electric machine has dropped to at least a second threshold, which is lower than the overvoltage threshold, the electric machine is reactivated and the VVC is set to a normal operating mode.

In a further embodiment, the method also includes the reconnection of the electric machine during the drive cycle.

In a further embodiment, in the method, disabling the VVC switches the VVC to a restricted mode of operation, wherein the limited mode of operation enables the vehicle to maintain vehicle propulsion during the drive cycle.

In another embodiment, the method further includes commanding the VVC to run in a mode in which high voltage is conducted from a high voltage electrical connection to the battery to rapidly drain high voltage in response to the overvoltage fault.

In another embodiment, in response to the overvoltage fault, the VVC is set to a mode that prevents the provision of a boost voltage to the at least one electric machine.

In accordance with one or more further embodiments of the present disclosure, an electric vehicle is provided that includes a traction battery, at least one electric machine, and a variable voltage converter (VVC). The electric vehicle includes at least one control device configured to detect an overvoltage fault when the voltage of an electrical machine exceeds an overvoltage threshold. In response to the overvoltage fault, the electric machine and the VVC are deactivated. If it is determined that the voltage of the electric machine has dropped to at least a safety threshold that is lower than the overvoltage threshold, the controller is configured to switch the VVC to a restricted operating mode. If it is determined that the voltage of the electric machine has dropped to at least a third threshold, which is lower than the safety threshold and the overvoltage threshold, the controller is configured to reactivate the electrical machine and set the VVC to a normal operating mode. The limited operating mode allows the vehicle to maintain vehicle propulsion during the drive cycle while the electric machine is recovering from a transient condition that has triggered the overvoltage fault.

In a further embodiment, the electrical machine comprises at least one inverter, the overvoltage fault occurring at the at least one inverter.

In another embodiment, the overvoltage fault occurs on at least one insulated gate bipolar transistor (IGBT).

In another embodiment, the electric vehicle includes an inverter, and the controller is further configured to command the VVC to run in a shunt mode, wherein power is supplied from the inverter to the battery while the electric machine is deactivated.

In a further embodiment, the at least one control device is also configured to re-activate the failed electric machine during the drive cycle.

In accordance with one or more embodiments of the present disclosure, a method of controlling a hybrid electric vehicle is provided. The method includes detecting an overvoltage fault when the voltage of an electrical machine exceeds an overvoltage threshold. The electric machine is deactivated in response to the overvoltage fault. If it is determined that the voltage of the electric machine has dropped to at least a safety threshold which is lower than the overvoltage threshold, a variable voltage converter (VVC) is switched to a restricted operating mode. If it is determined that the voltage of the electric machine has dropped to at least a third threshold, which is lower than the safety threshold and the overvoltage threshold, the electric machine is reactivated and the VVC is set to a normal operating mode. The limited operating mode allows the vehicle to maintain vehicle propulsion during the drive cycle.

In another embodiment, in response to the overvoltage fault, the VVC is set to a mode that prevents the at least one electric machine from being supplied with a boost voltage.

1 FIG. 10 is a circuit diagram of a hybrid electric vehicle according to an embodiment of the disclosure; FIG.

2 is a block diagram illustrating an example of a control system of the vehicle 1 illustrated;

3 is a circuit diagram of a part of the vehicle 1 ;

4 is a circuit diagram of a variable voltage converter (VVC) off 3 ;

5 FIG. 10 is a flowchart of an algorithm used in a control system of the vehicle. FIG 1 implemented according to an embodiment of the disclosure;

6 is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

7 is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

8th is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

9 is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

10 is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

11 FIG. 12 is a diagram illustrating a system response and recovery strategy of the vehicle 1 according to an embodiment of the disclosure;

12 is a flowchart of another algorithm that is in the control system of the vehicle 1 implemented according to an embodiment of the disclosure;

Embodiments of the present disclosure are described herein. However, it should be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features may be larger or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be considered as limiting, but merely as an illustrative basis for teaching various applications of the present invention to those skilled in the art. As those skilled in the art will appreciate, various features illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to obtain embodiments that are not explicitly illustrated or described. The combinations of illustrated features represent representative embodiments of typical applications. However, for certain applications or embodiments, various combinations and modifications of the features may be desired in accordance with the teachings of this disclosure.

In 1 is a hybrid electric vehicle 10 shown with a power-split drive train. A vehicle control system 12 is provided and may be referred to generally as a controller. The vehicle control system 12 controls the power distribution in the drive train or in the drive unit of the vehicle 10 ,

The vehicle 10 includes a traction battery 14 , The battery 14 has a two-way electrical connection, so that the battery 14 For example, receives and stores electrical energy by Rekuperationsbremsen. The battery 14 also provides energy for an electrical machine, such as an electric traction motor 16 , ready.

Although the tax system 12 of the vehicle 10 in 1 As a single control device, such a control system may include more than one control device if desired. For example, a separate battery control module may be the battery 14 direct control. In addition, a separate engine control module can work directly with the engine 16 and with the other control devices in the vehicle 10 be connected. It is understood that all provided control devices in the vehicle 10 can be referred to as "control device" and that the vehicle control system 12 is not necessarily limited to only one control device. Separate other control devices and their hierarchy are in 2 described in more detail.

An inverter 15 is provided to convert direct current from the battery to alternating current for driving the electric machine. The inverter 15 can also selectively remove the electricity from the battery 14 to the engine 16 enable / disable. Alternatively, the inverter 15 during recuperation braking convert alternating current from the electric machine to direct current, thus reducing the electrical power in the battery 14 is stored.

An internal combustion engine 18 also provides an energy source for the vehicle 10 dar. The vehicle control system 12 controls the operation of the engine 18 , Both the engine 16 as well as the engine 18 are capable of a transmission 20 driving, ultimately a torque to the wheels of the vehicle 10 supplies.

The motor 18 provides power for a torque shaft 22 ready to use a one-way clutch with a planetary gear set 24 connected is. The drive shaft 22 drives the planetary gear set 24 at. The planetary gear set 24 includes a ring gear 26 , a sun wheel 28 and a planet carrier arrangement 30 , The drive shaft 22 can be driven with the carrier assembly 30 connected, which, when driven, the ring gear 26 and / or the sun gear 28 can turn. The sun wheel 28 Can be driven by a generator 32 be connected. The generator 32 can with the sun gear 28 be engaged so that the generator 32 himself with the sun wheel 28 turns, or can not be engaged, so the generator 32 not with the sun gear 28 rotates. Like the engine 16 can the generator 32 may be referred to as an electric machine that, when used with other vehicle powertrain configurations, is capable of generating both electrical energy and propulsion power.

If the engine 18 drivable with the planetary gear set 24 connected, the generator generates 32 Energy as a response element of the operation of the planetary gear set 24 , Electric energy coming from the generator 32 is generated via electrical connections 36 to the battery 14 transfer. The battery 14 It also receives and stores electrical energy from recuperation braking in a known manner. The battery 14 puts the stored electrical energy to the engine 16 ready for operation. The part of the energy coming from the engine 18 for the generator 32 is also possible to go directly to the engine 16 be transmitted. The battery 14 , the motor 16 and the generator 32 are via electrical connections 36 connected in an electrical branch path. The vehicle control system 12 controls the components in the drive train to provide the appropriate torque distribution for the wheels.

It is understood that the engine 16 and the generator 32 both can be referred to as electrical machine. Every electric machine can work as a generator by taking a torque from the engine 18 receives and AC voltage for the inverter 15 Provides the inverter 15 the voltage is converted to DC voltage to the battery 14 to load. Each electric machine can also function as a generator by utilizing recuperation braking to convert the braking energy of the vehicle into electrical energy stored in the battery 14 should be saved. Alternatively, each electric machine may operate as a motor, with the electric machine taking energy from the inverter 15 and the battery 14 receives and torque through the gearbox 20 and finally to the wheels 58 provides.

The inverter 15 drives the engine 16 and the generator 32 selectively. The inverter 15 can be a motor inverter for selective deactivation of the motor 16 and a generator inverter for selectively deactivating the generator 32 include.

The vehicle 10 also has a variable voltage transformer (VVC) 60 Also referred to as a boost converter, include the voltage between the battery 14 and the engine 16 and the generator 32 to vary. The VVC 60 is used to voltage the battery 14 to raise to a higher voltage. The higher voltage in a hybrid electric Powertrain system can be used for multiple purposes, such as optimizing torque capacity for electrical machines, system loss optimization, and other optimization of hybrid electric systems. The VVC 60 allows the use of a smaller battery pack with lower voltage in the vehicle 10 while retaining the functionality associated with the higher voltage. A smaller battery pack may have advantages such as lower cost, smaller size and fewer housing restrictions. The VVC 60 is in 3 and 4 described in more detail.

The vehicle 10 can by the engine 18 alone, by the engine 18 and the generator 32 alone, by the battery 14 and the engine 16 alone or by a combination of the engine 18 , the battery 14 , of the motor 16 and the generator 32 operate. In a mechanical drive mode, or a first mode of operation, the engine becomes 18 activated to a torque via the planetary gear set 24 provide. The ring gear 26 distributes the torque to translation wheels 38 , the meshing wheel elements 40 . 42 . 44 and 46 include. The wheels 42 . 44 and 46 are mounted on a countershaft, and the wheel 46 transfers the torque to the wheel 48 , The wheel 48 then transmits the torque to a torque output shaft 50 , In mechanical drive mode, the engine can 16 also be activated to the engine 18 when driving the gearbox 20 to support. If the engine 16 actively supports, transmits the wheel 52 a torque on the wheel 44 and the countershaft.

In an electric drive mode (EV mode), or a second mode of operation, the motor is 18 deactivated or otherwise prevented from torque on the torque output shaft 50 transferred to. In EV mode, the battery is driving 14 the engine 16 to give it a torque over the translation wheels 38 and to the torque output shaft 50 transfers. The torque output shaft 50 is with a differential and axle mechanism 56 connected, which produces a torque on the drive wheels 58 transfers. The vehicle control system 12 controls the battery 14 , the engine 16 , the engine 18 as well as the generator 32 Thus, in either the mechanical drive mode or the EV mode according to the torque requirements of the driver, a torque on the wheels 58 is transmitted.

As described above, there are two power sources for the drive unit. The first source of energy is the engine 18 , which is a torque for the planetary gear set 24 provides. The other source of energy only affects the electric drive system that drives the engine 16 , the generator 32 and the battery 14 includes, the battery 14 as energy storage medium for the generator 32 and the engine 16 serves. The generator 32 can through the planetary gear set 24 operated and alternatively serve as a motor and energy to the planetary gear set 24 respectively.

It is understood that in the vehicle 10 Although a power-split drive train is shown, the vehicle 10 but can also contain numerous other configurations. In this regard, it is envisioned that individual components of the powertrain will vary to suit different specific applications. For example, in another configuration that does not have a planetary gear set 24 comprises an electric machine (motor / generator) which serves as a generator by receiving torque from the engine or from the recuperation braking, while the same electric machine can also serve as an engine by receiving energy from the traction battery and by the Gear provides a torque. Other vehicle configurations of vehicle drivelines and electrical machine implementations are also contemplated and thus to be considered within the scope of the present disclosure.

In 2 is a block diagram to see that a vehicle control system 12 in the vehicle 10 illustrated. A driver gives a request 62 by, for example, depressing the accelerator pedal to input an acceleration request, or by depressing the brake pedal to input a brake request. The driver inputs 62 are controlled by a vehicle system control device (FSS) 64 receive. The FSS 64 processes these driver inputs 62 and transmits commands by the vehicle 10 ,

The vehicle control system 12 can be electric with different subsystems in the vehicle 10 be connected and serves as the overall control of the vehicle 10 , The FSS can be accessed via a vehicle network 65 be electrically connected to different subsystems and communicate with them. The vehicle network 65 continuously transfers data and information to the vehicle-based systems. The vehicle network 65 can be a Controlled Area Network (CAN) bus that is responsible for transferring data to and from FSS 64 and other various control devices or subsystems or components thereof. As in 2 shown is the FSS 64 for example via the vehicle network 65 with a hybrid control device (HSV) 66 , a battery control module (BSM) 72 and an engine control unit (MSE) 68 be connected.

The HSV 66 controls the hybrid-specific components of the vehicle 10 , such as the engine 16 , the generator 32 , the battery 14 and / or the inverter 15 , The HSV 66 is in communication with the MSE 68 so the HSV 66 the MSE 68 can command the engine 18 to steer in different ways. A battery control module (BSM) 72 can also with the HSV 66 communicate. The BSM 72 can get orders from HSV 66 Receives and controls the energy distribution of the battery 14 ,

The HSV 66 is also in communication with a motor / generator control unit (MGSE) 70 , The MGSE 70 communicates with the HSV 66 via a single peripheral interface (SPI) 71 , The SPI 71 is a serial bus with four wires. The SPI 71 is a very simple hardware interface and is not limited to a certain maximum clock speed, potentially allowing high throughput. The MGSE 70 receives commands from the HSV 66 and controls the engine 16 , the generator 32 and the VVC 60 , As in 2 also shown is the MGSE 70 in communication with inverter control devices 74 , The motor / generator inverter control devices 74 receive commands from the MGSE 70 and open and close switches in the inverter 15 to activate and deactivate the flow of energy to and from the electrical machines.

Earlier hybrid electric vehicles used only one control module to control the engine, generator, and VVC. Within the control module, one microcontroller was used to control the motor, and another microcontroller to control the generator, while a third microcontroller controls the VVC. However, it proved difficult to control the VVC when it was disconnected from the motor / generator, and it proved too slow in transmitting information from the motor or generator to the VVC control devices in the HSV. Therefore, it is advantageous for the VVC, the motor, the generator and the corresponding inverters from a control device, for example, the in 2 MGSE shown to control.

Therefore, in the illustration in 2 provided a hierarchy of control devices. Other hierarchies of control devices are provided without departing from the scope of the present disclosure. For example, the FSS 64 directly with the MGSE 70 communicate without a HSV 66 is available. Other configurations are also contemplated that may be beneficial to various specific vehicle architectures.

The vehicle control system 12 controls the individual control devices according to the requested torque and the power requirement. Again, it will be understood that more or less control devices are also provided as described herein, and that one or more of these control devices may cooperatively cooperate to perform certain tasks. Any one or all of these controllers or combinations thereof may be simply referred to as a "controller".

With reference to 3 and 4 Now, a circuit diagram of a part of a hybrid electric vehicle will be described 10 and vehicle control system 12 described in more detail. As explained above, the VVC stands 60 in communication with and controlled by the MGSE. Besides, the VVC is 60 with the motor / generator inverter control devices 74 connected. More specifically, the VVC 60 used to reduce the voltage of the battery 14 in a multi-purpose HEV powertrain system to increase to a higher voltage level, for example, but not limited to, optimizing torque capacity for electrical machines and system loss optimizations.

The battery 14 is with the VVC 60 along an input page 76 connected. The battery 14 puts the VVC 60 a low voltage ready. The VVC 17 raises the low voltage from the battery 14 then to a higher voltage and gives the higher voltage on an output side 78 out. The output page 78 of the VVC 60 puts the high voltage to the high voltage bus 36 for use by the inverter 15 and then through the engine 16 and the generator 32 ready. As in 3 The engine can be shown 16 and the generator 32 each a separate inverter 15 exhibit. The VVC 60 Although described as having an input side and an output side, it should be noted that the path in a travel mode from the battery through the VVC leads to the high voltage bus. In a regeneration mode, on the other hand, the path is reversed.

A sensor 80 is located between the battery 14 and the VVC to the voltage signal along the input side 76 of the VVC 60 to eat. More precisely, the sensor represents 80 a voltage signal ready, showing the voltage from the battery 14 indicates. A second sensor 82 is located along the output side 78 between the VVC 60 and the inverters 15 , The sensor 82 provides a signal representing the voltage from the high voltage bus 36 indicates. The sensors 80 . 82 provide a signal that measures the measured voltage along the input side 76 or output page 78 indicates. Under normal operating conditions, the measured voltage signal is from the sensors 80 . 82 within a suitable specified range. However, if the measured voltage signal of the sensors deviates from the appropriate specified range, this may indicate that an error has occurred or that one of the sensors 80 . 82 has failed.

In 4 is a circuit diagram of the circuit of the VVC 60 to see. The VVC 60 generally consists of an inductor 84 , two circuit breakers 86 and 88 and associated gate drive circuits 90 , as in 4 you can see. The two circuit breakers 86 . 88 consist of an insulated gate electrode (IGBT) 92 and an anti-parallel diode 96 , As in 4 the switches are shown as the upper switch 86 and lower switch 88 arranged. There are also several IGBTs 92 that the inverter 15 are assigned, respectively for the engine 16 and for the generator 32 , as in 4 you can see.

The circuit arrangement of the VVC 60 allows two-way current flow, depending on the requirements of the vehicle, such as drive or recovery. For example, if the upper switch 86 is closed and the bottom switch 88 open, power flows in one direction through the antiparallel diode 96 , Similarly, when the upper switch flows 86 is open and the bottom switch 88 closed, power in one direction through the antiparallel diode 96 , However, if both the upper switch 86 as well as the lower switch 88 are closed, current flows in both directions and generates a voltage boost. The generated boost voltage becomes the inverter 15 issued the engine 16 and the generator 32 controls. As previously explained, in the vehicle by increasing the voltage through the VVC 60 is allowed to use a smaller battery pack, saving costs and battery space.

Certain fault conditions may be detected by one or more of the control devices that have failed in one of the powertrain components, eg, the engine 16 , the generator 32 , the VVC 60 or the inverter 15 , Show. If a fault is detected in one of the components, a restricted operating strategy (LOS) may be implemented to allow the operator of the vehicle to continue driving while disabling certain individual components. This prevented a complete shutdown of the vehicle 10 which may be undesirable for drivers. The fault conditions that can cause the vehicle 10 and / or the vehicle control system 12 entering a LOS mode may include temperature, current, and / or voltage values of a powertrain component that are outside an acceptable threshold. An error condition can be caused by a transient incident and be short-lived; however, reading a value outside of a threshold may cause the vehicle control system 12 the individual shutdown of the affected component commands, while it commands a LOS mode, so that the operator of the vehicle 10 can continue driving.

In 5 is an embodiment of the LOS mode as 100 shown. A diagnosis is made on the engine 16 , at the generator 32 , at the VVC 60 and at the inverter 15 , which is connected to each of the electrical machines performed. The diagnostic determines if the LOS mode is necessary and a temporary deactivation of this component is to be commanded. The MGSE 70 begins to perform the diagnosis as in block 102 is shown. Next, as in block 104 shown, determines whether a fault condition in the engine and / or engine inverter is present or not. If such a fault condition exists, an LOS counter is incremented, as in block 106 is shown. The LOS counter may be a one-digit counter or an identification means. Once the LOS counter has been incremented by one, as in block 108 a temporary engine deactivation is indicated as TRUE. The engine is instructed to deactivate, as in block 110 is shown. The motor can be deactivated by opening switches in the inverter or by opening another switch in connection with the motor.

If there is no fault condition in the engine and / or engine inverter, then it is determined if the LOS counter is greater than zero, as in block 112 is shown. If the LOS counter is not greater than zero, the temporary engine deactivation is marked as FALSE and the engine is commanded to activate or remain activated as in block 116 is shown. However, if the LOS error counter is greater than zero, then the LOS counter is lowered or decremented, as by block 118 is shown. After the LOS counter has been decremented, it is determined whether the error counter has reached zero, as by block 120 is shown. If the LOS counter is zero, then the process proceeds to mark the motor deactivation as FALSE, as by block 114 is shown, and the engine is instructed to activate or remain activated, as by block 116 is shown. If the error counter remains greater than zero, then the process proceeds again to deactivate the engine, as by the blocks 108 . 110 is shown. Finally, the TRUE and FALSE tags are sent to the vehicle control system, as by block 122 is shown. Based on the information sent to the vehicle control system, the vehicle may act as described in relation to FIG 6 given is.

By requiring that the error counter be zero, as by block 120 12, the control system ensures that, even if it is determined that there is no fault condition in the engine and / or engine inverter, the engine is temporarily deactivated for a short time if the LOS fault counter is still above zero. This allows the diagnostics to run multiple times, reducing the LOS error counter on each diagnostic pass until the counter reaches zero. Multiple checks of the engine and / or engine inverter are therefore performed while the engine is deactivated before the engine is reactivated if no fault condition is detected.

The diagnostics performed by the MGSE serve to temporarily shut off the engine when an error is detected. While the engine is temporarily deactivated, the vehicle is running in a temporarily reduced power mode. However, if the fault condition exists only for a brief moment (e.g., less than 1 second), the LOS mode may be adjusted and the engine rapidly reactivated, thereby reducing the disturbances experienced by the vehicle operator. It will be appreciated that all of the diagnostics can be done in less than a second, for example, in twenty microseconds, whereby the time the engine is temporarily shut down may not be perceived by the operator of the vehicle.

As in 5 shown, will be the LOS mode 100 and performing the diagnostic procedure as in block 102 shown performed for the generator and the VVC and the engine. The diagnostics are generally performed simultaneously for the motor, generator, associated inverter, and VVC, so that a check for fault conditions in each component is continuous. The MGSE can thus temporarily disable any or all of the engine, generator or VVC. It is envisaged that the diagnostics for other components, such as the other engine, can be performed.

6 shows a flowchart 200 Another embodiment of the LOS mode, implemented by a control device or the vehicle control system. As described above, the MGSE sets a flag for either TRUE or FALSE to temporarily disable or activate the engine, as by the blocks 108 respectively. 114 is shown. The TRUE and / or FALSE marks are obtained from the vehicle control system by the MGSE, as by block 202 is shown.

If the flag is FALSE, then the vehicle control system commands the MGSE to diagnose 102 to return, as by block 204 is shown.

However, if the flag is TRUE, then a determination is made as to whether the engine has been temporarily disabled for at least one threshold duration, as by block 206 is shown. If the engine has been deactivated for at least the threshold duration, then the engine may be permanently disabled for the respective key cycle, as by block 208 is shown. In one embodiment, the threshold duration may be about one second, such that the motor is permanently deactivated during the respective key cycle if it has been temporarily disabled for at least one second. However, any suitable threshold duration is provided, and the threshold duration may vary depending on other factors. A key cycle may also be referred to as the drive cycle or duty cycle and corresponds to the duration from the time the vehicle is put into service, ie turning the ignition key, until the vehicle is turned off by turning the ignition key. During a new key cycle, the engine, or any other failed device, such as the VVC or inverter, may be reactivated as described with reference to FIG 7 is described.

The referring to 5 and 6 described algorithms provide a diagnostic test of the engine, the generator, the VVC or any other powertrain component ready. In short, when it is determined that the respective powertrain component is under an error condition, this component is temporarily deactivated. The diagnostics are continuously run on this component while it is temporarily disabled. If the component recovers from the fault condition or the fault was transient, allowing the component to run within the time threshold under normal conditions, the component may be turned on again. However, if the component does not recover from the fault condition during the time threshold, the component is permanently disabled during the respective key cycle and can only be reactivated in a new key cycle (eg, turning the vehicle off and on).

7 shows a flowchart 300 Another embodiment of the LOS mode, implemented by a control device or the vehicle control system. As by block 302 The vehicle is instructed to start and a new key cycle is commanded. Initially, the electrical machines, including the engine, the generator and the VVC are deactivated. A row of Pre-start safety checks are performed before the vehicle is initialized.

For example, the vehicle control system checks that the current sensor zero position is complete, as by block 304 is shown. The current sensor zero position must be complete in all electrical machines. The current sensors must have a zero reading when the current is zero to get accurate readings when the current goes up during cranking. Next, a self-test of the VVC is performed, as by block 306 is shown. The VVC self-test ensures that any errors in the VVC are detected and removed. In addition, it is determined whether there are torque errors, such as by block 308 is shown. In other words, the available power and / or torque of the electric machines must be judged to determine if a required torque can be achieved by the electric machines.

The duty cycle commands provided to the electric machine are deactivated or reset by the controller, as by block 310 is shown. The reset of the duty cycle puts the electrical machines in a safety mode, which protects the hardware. Only after the fault conditions have been removed, the duty cycle commands can be turned on again, whereby the electric machine can be safely controlled. This is called a "soft reboot", which does not require a new key cycle, as opposed to a "hard reboot" that requires the vehicle to be shut down. Finally, as by block 312 is determined, errors in the hardware determined before the vehicle can start.

Once the pre-start safety checks have been successfully completed, the vehicle starts and the electric machines can start, as by block 314 is shown. The electric machines are also fully turned on, and the vehicle can be driven.

During operation of the vehicle, referring to 5 and 6 described diagnostic algorithms executed as by block 316 is shown. The electrical machines are continuously checked for faults so that each of them can be temporarily disabled according to the procedures previously described.

If a request to deactivate any of the electrical machines at block 316 is detected, then the electric machine is deactivated, as by block 318 is shown. To turn the electric machine back on, the controls in the vehicle must undergo a series of safety checks and safety processes before the electric machine locks up 314 is switched on again. The safety checks and processes allow the vehicle to continue to provide the electric machines with propulsion without a key cycle being present.

In one of the safety checks, as by block 320 2, the controller determines whether a temporary deactivation of the electric machine is still required, as previously with respect to Block 110 in 5 has been described. If no deactivation of the electrical machines is required, the controller may determine if there is a request that the electrical machines should be in a deactivated or permanently deactivated mode, as by block 322 is shown. If the electrical machines are not deactivated, a torque compliance check is performed, as by block 324 is shown. The torque compliance test is similar to the test with reference to block 308 is carried out.

Next, a performance restriction and equilibrium check is performed, as by block 326 is shown. In this test, the controller may determine whether a process is underway, in which electric power is limited to one of the electric machines, or that one of the electric machines has no power or torque restriction much higher than that of the other electric machine. The power restriction mode is set in 8th described in more detail. Finally, an overcurrent test is performed, as by block 328 is shown. The overcurrent test determines whether any electrical machine is supplied or outputs an amperage value above a given threshold. When all safety checks are satisfied, the pre-start / reactivation tests are complete and the system starts back at block 302 until the deactivated electric machine at block 314 is activated again.

8th shows a flowchart 400 Another embodiment of the LOS mode, implemented by a control device or the vehicle control system. 8th describes a LOS mode in which a power restriction mode is implemented when a fault condition is detected in one of the electric machines. In recent hybrid electric vehicles, failures or fault conditions in a hybrid electric vehicle powertrain have been difficult to eliminate without reducing the performance of the vehicle during driving or completely stopping the vehicle, and so on then required a key cycle to resume partial operation. A key cycle was necessary to properly maintain the power balance in the failed device. In a hybrid electric power transmission, if failure is detected in one of the devices, eg, an electric machine, action on only the failed device would result in power imbalance, resulting in unstable performance and other control related errors.

To avoid power imbalances and unstable performance, the flow chart describes 400 in 8th the process in which the vehicle enters the LOS mode when one of the electric machines fails while driving, and continues the hybrid electric drive train with the second electric machine, without a key cycle is necessary. The one in the flow chart 400 The described process allows the control system to quickly bring the power to equilibrium when one of the electric machines fails, and allows the other electric machine to continue to power the vehicle.

At first, as by block 402 3, the control system detects a failure in a first hybrid electric driveline device and disables the device in response to the fault condition. The failure can occur in one of the electrical machines or in the associated inverters. In response to the error condition and the disabled device, the control system initiates a power restriction mode, as by block 404 shown. Initially, the power restriction mode is performed at a high execution speed. For example, the high speed may be an execution speed of 100 microseconds.

While still running at a high execution speed, the control system temporarily deactivates the second device, as by block 406 is shown. The VVC is also temporarily placed in a shunt mode, as by block 408 is shown. The shunt mode of the VVC allows for rapid dissipation of high voltage from the electrical machines to the low voltage input side of the VVC. An error may also be displayed to the driver in response to the failure, as by block 410 is shown.

After a threshold period, the control system may initiate a power restriction mode with a lower execution speed, such as by block 412 is shown. For example, the threshold duration may only be 20 milliseconds, or any other threshold duration sufficient to allow the high voltage to be dissipated, so that the devices are not exposed to the danger of overvoltage, which could lead to further failures. The control system initiates the lower execution speed so that further diagnostics can be performed.

Once the lower speed power limit mode is initiated, the control system reactivates the second device that has not failed. However, the second device is reactivated in a torque restriction mode, as by block 414 is shown. In the torque restriction mode, the torque for the functional device is limited to the functional device based on the vehicle operation. The maximum torque "Tmax" in the LOS mode is limited based on the following formula: T _max = (I _max × V _battery ) / ω

In other words, the maximum torque in the LOS mode is limited based on the maximum allowable amperage of the high voltage bus in the LOS mode times the voltage from the battery divided by the speed of the second device. In one embodiment, the maximum allowable current in the LOS mode is a fixed value, for example, 150 A. The battery voltage may be variable.

Once the functional device is reactivated in a functional module, the control system checks whether the first device is still down or disabled, as by block 416 is shown. If the MGSE or HSV requests that the first device be deactivated or it still fails, a power restriction counter is incremented, as by block 420 is shown. However, if there is no error and there are no deactivation requests from the controllers, the control system may exit the power restriction mode, as by block 424 is shown. By exiting the power constraint mode, the control system also exits the low execution speed.

The control system then returns the power limit timer to zero, as by block 426 is shown. Once the power limit timer is set to zero and the LOS mode is completed, the control system may also reactivate the first and second devices, as by block 428 is shown. The reactivation of the devices includes getting out of the torque limiting mode and returning to normal.

On the other hand, if the first device is still in a failure state, the MGSE or HSV request that the device be disabled or set to a LOS mode, and the control system determines whether the power restriction time counter is greater than a threshold, as by block 432 is shown.

If the power limit timer has exceeded a threshold, it exits the low speed diagnostic mode, as by block 434 is shown. Then, the torque-limiting mode for the functional device is permanently maintained, as by block 436 is shown.

By maintaining the torque limiting mode, the device is permanently deactivated. In some embodiments, the device may be permanently disabled only up to a new key cycle of the vehicle. The device can be permanently disabled for various reasons, including those in the 5 - 7 described method.

9 shows a flowchart 500 Another embodiment of the LOS mode, implemented by a control device or the vehicle control system. A high voltage battery signal, also referred to as HSBATT signal, is received by the controller, eg, the MGSE, as by block 502 shown. The high voltage battery signal is measured by the sensor along the input side of the VVC. Based on the high voltage battery signal provided by the sensor, the controller determines whether the high voltage battery signal is valid, as by block 504 is shown. The high voltage battery signal is valid when the signal is within an acceptable range.

If the HSBATT signal is valid, the controller continues to use the high voltage battery signal, as by block 506 and the VVC may function normally, for example, the VVC providing a boosting output to the inverters and electrical machines as in 3 and 4 is described.

However, if the high voltage battery signal is outside the acceptable range, the signal is determined to be invalid. If the high voltage battery signal is invalid, then the signal is set to an error condition, as by block 508 is shown. When the high voltage battery signal is set to the fault condition, the MGSE communicates with the HSV to determine if an alternative signal is available to provide the high voltage battery signal and prevent shutdown or short circuit of the electric machines and the vehicle.

As described above, the HSV is able to communicate via the vehicle network, e.g. CAN, communicate. For example, the HSV may communicate with the BSM at the vehicle network to receive an alternative battery voltage signal from the BSM. The alternative battery voltage signal from the BSM may be a measured voltage measured in the BSM. Alternatively, the alternate battery voltage signal may be derived from other battery readings in the BSM or other vehicle system control devices communicating with the vehicle network.

The MGSE determines whether the alternative voltage signal provided by the vehicle network is valid, as by block 510 is shown. The alternate battery voltage signal is considered a valid signal if the battery voltage is within an acceptable range. If the alternative battery voltage signal is recognized as valid by the BSM, then the alternate battery voltage signal replaces the HSBATT, as by block 512 is shown. By using the alternative battery voltage signal instead of the HSBATT, the VVC can continue to run normally, as by block 514 is shown. During normal operation, the VVC can provide a voltage boost from the battery voltage on the input side to the inverter and to the electrical machines on the output side. Thus, the electrical machines can continue to operate normally by the introduction of alternative signals during operation, despite the failed high voltage battery signal.

The vehicle may also indicate an error to the driver, as by block 516 is shown. The fault can be displayed as a lamp in the form of a wrench to inform the driver about the error condition. The fault condition of the high voltage battery signal can be triggered by a failure of the sensor. The display may indicate that the sensor needs to be replaced.

If the MGSE determines that the alternative signal is not valid, the control system ignores the alternative signal, as by block 518 is shown. For example, the alternative signal may be invalid if it is outside of an acceptable range or threshold. If the alternate signal is invalid, this may indicate a secondary error.

10 shows a flowchart 600 Another embodiment of the LOS mode, implemented by a control device or the Vehicle control system. A high voltage battery bus signal, also referred to as HVDC signal, is received by the controller, eg, the MGSE, as by block 602 is shown. The high voltage bus signal is measured by the sensor along the output side of the VVC. Based on the high voltage bus signal provided by the sensor, the controller determines if the high voltage bus signal is valid, as by block 604 is shown. The high voltage battery signal is valid when the signal is within an acceptable range.

If the HVDC signal is valid, the controller continues to use the high voltage bus signal, as by block 606 and the VVC may operate normally, with the VVC providing a boosting output to the inverters and electrical machines, as in FIG 3 and 4 is described.

However, if the high voltage bus signal is outside the acceptable range, the signal is determined to be invalid. If the high voltage bus signal is determined to be invalid, then the signal is set to an error condition, as by block 608 is shown. If the signal is determined to be invalid, then the HVDC signal is set to fail and a LOS mode is implemented to maintain the operation of the electric machines and allow the operator of the vehicle to continue driving.

When the high voltage bus signal is set to the fault condition, the MGSE attempts to use the high voltage battery signal, HSBATT, from the input side of the VVC instead of the high voltage bus signal. The MGSE determines if the high voltage bus signal is valid, as by block 610 is shown. It is contemplated that the controller may use any HSBATT signal, such as the high voltage bus signal measured by the sensor or the alternative battery voltage signal provided by CAN via the HSV to the MGSE, as in FIG 9 is explained.

As previously discussed, the high voltage battery signal is determined to be a valid signal when the battery voltage is within a valid range. If the high voltage battery signal is determined to be valid, then the HSBATT is used instead of the high voltage bus signal, as by block 612 is shown.

If a high voltage battery signal is used instead of the high voltage bus signal, the VVC may continue to run, but the VVC will be put in a LOS mode, as by block 614 is shown. In LOS mode, the VVC is in a shunt mode. In shunt mode, the VVC is not allowed to provide a boost, such as by block 616 is shown. The vehicle may also indicate an error to the driver, as by block 618 is shown. Again, the fault can be displayed as a lamp in the form of a wrench to inform the driver about the error condition. The fault condition in the high voltage bus signal can be triggered by a failure of the sensor. The display may indicate that the sensor needs to be replaced.

If the MGSE determines that the HSBATT signal is not valid, the control system ignores the alternative HSBATT signal, as by block 620 is shown. For example, the alternative signal may be invalid if it is outside of an acceptable range or threshold. If the alternate signal is invalid, this may indicate a secondary error.

It will be understood that while reference has been made to the deactivation and activation of the engine, but similar algorithms for the engine 16 , the generator 32 , the inverter 15 and the VVC 60 are provided. In other words, if a fault condition in one of the engine 16 , the generator 32 , the inverter 15 and the VVC 60 is present, the methods described above are used in each of these components and in other powertrain components.

The 11 - 12 show a troubleshooting strategy for hardware errors. Hardware failure in one subsystem can affect other subsystems and cause more errors. One of the more common findings that occurs as a result of outages is an inverter overvoltage fault 15 , The overvoltage fault is caused by the inverter hardware. When triggered, the hardware can be the motor inverter 15 and / or the generator inverter 15 as well as the VVC 60 disable, resulting in a vehicle QOR. Other hardware provisions that are less severe than hardware over-voltage errors are IGBT errors. An error of any IGBT 92 If necessary, this affects only the affected device (s). However, IGBT errors can occur due to transient events rather than actual physical damage to the failed IGBT. The error can be in any IGBT 92 occur to the inverter 15 for the engine 16 or generator 32 assigned to one or both IGBTs 92 at the VVC 60 , According to one embodiment, the vehicle control system is 12 configured to fix hardware fault conditions, such as IGBT errors. 11 is a voltage diagram 700 an inverter that has a strategy to remedy a Overvoltage curve shows. As in 11 hardware diagnostics represents an inverter voltage at one point 710 fixed if the voltage is an overvoltage error threshold 714 exceeds.

If the voltage is the overvoltage error threshold 714 exceeds, the control system can the engine 16 , the generator 32 and the VVC 60 deactivate. The MGSE 70 can also be set to an error indicator to indicate the hardware problem.

When the inverter voltage is the threshold 714 The control system strategy waits for the point to pass 710 on that the tension is below a safety threshold 720 falls. The control system may wait a predetermined period of time or set an error counter, such as in FIG 12 is shown in more detail. At the point 724 at which the inverter voltage is below the safety threshold 720 falls, the control system resets the hardware error to remove the action affecting the various devices, eg the motor 16 , the generator 32 and the VVC 60 , has blocked. Once the error is reset, the VVC can 60 be forced into a temporary shunt LOS mode. As previously discussed, the shunt mode may allow the high voltages from the electrical machines to be rapidly dissipated to the low voltage input sides of the VVC. The VVC shunt mode can reduce the likelihood of subsequent motor spikes 16 , Generator 32 and / or VVC 60 which could lead to secondary errors. Resolving a hardware inverter overvoltage fault as quickly as possible within the same drive cycle reduces the number of vehicle QORs due to secondary faults and allows for longer vehicle usability.

The control system strategy waits for the voltage to fall below a recovery threshold 730 falls. At the point 734 if the inverter voltage is below the recovery threshold 730 The control system will return the MGSE default settings. If there are no other errors, the engine will recover 16 , the generator 32 and the VVC 60 from the respective LOS modes. If other errors exist, each individual device may remain in its appropriate mode.

12 is a flowchart that is an example of the engine's troubleshooting strategy 16 , the generator 32 or the VVC 60 shows that on an error in one of the IGBT 92 based. 12 shows a flowchart 800 Another embodiment of the LOS mode, implemented by a control device or the vehicle control system. The controller, eg, an MGSE, receives an IGBT error signal for a particular device, as by block 802 is shown. The IGBT error signal may be related to any device, such as the motor 16 , the generator 32 or the VVC 60 ,

An IGBT fault is caused by the hardware of the motor inverter 15 , the generator inverter 15 or the VVC 60 detected. The IGBT error signal then becomes the controller 12 Posted. Based on the IGBT error signal, the controller determines whether the IGBT error signal reading corresponds to the last loop of the current IGBT error signal reading, as by block 804 is shown. If the current IGBT error signal reading matches the last loop, the control system may initiate a slower execution speed so that further diagnostics may be performed to determine if any of the IGBTs 92 still failed, as by block 806 is shown. If the current IGBT error signal reading does not match the last loop, the control system determines the state of the IGBT 92 as by block 810 is shown.

If the IGBT 92 is still failed or has an error, an IGBT error counter is incremented, as by block 820 is shown. The control system sets a LOS mode for the failed device to temporarily disable the device, as by block 822 is shown, and then checks whether the engine inverter 15 or the generator inverter 15 or the VVC 60 still failed or disabled, as by block 416 is shown.

However, if there is no IGBT fault, the control system reduces the IGBT fault counter, as by block 826 is shown. If the IGBT error counter is set to zero, it can be exited from the LOS mode, as by block 830 is shown. Once the IGBT fault counter is set to zero and the LOS mode is completed, the control system may also reactivate other devices and return to normal operation. The processes, methods, or algorithms disclosed herein may be deliverable to, or implementable by, a processing device, controller, or computer that includes any existing programmable electronic control unit or dedicated electronic control unit. Similarly, the processes, methods, or algorithms may be stored as data and instructions that may be executed by a controller or computer in various forms, including, but not limited to, information permanently stored on non-writable storage media, such as ROMs. Devices are stored and information stored on changeable on recordable storage media, such as floppy disks, magnetic tapes, CDs, RAM devices and other magnetic or optical media. The processes, methods or algorithms can also be implemented in an executable software object. Alternatively, the processes, methods, or algorithms may be implemented in whole or in part using appropriate hardware components, such as application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), state machines, control devices or other hardware components or devices, or a combination of Hardware, software and firmware components.

Although examples of embodiments have been described above, it is not intended that these embodiments describe all possible forms included in the claims. The words used in the specification are words of description rather than limitation, and it is to be understood that various changes may be made without departing from the spirit and scope of the disclosure. As described above, the features of various embodiments may be combined to obtain other embodiments of the invention that are not explicitly described or illustrated. While various embodiments may be described as having certain advantages or as to one or more desired features as compared to other embodiments or embodiments of the prior art, those skilled in the art will recognize that one or more features or characteristics can be omitted to achieve desired overall system attributes that depend on the particular application and implementation. For example, these attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, ease of use, weight, manufacturability, ease of composition, and so forth. As such, embodiments that are described as being less desirable in terms of one or more characteristics than other embodiments or prior art implementations are not outside the scope of the disclosure and may be desirable for particular applications.

LIST OF REFERENCE NUMBERS

402

Steuerung stellt Ausfall fest und deaktiviert die 1. Vorrichtung

404

Initiierung des Leistungsbeschränkung-LOS-Modus mit hoher Geschwindigkeit

408

Vorübergehende Umstellung des VVC in Nebenschlussmodus

406

Vorübergehende Deaktivierung der 2. Vorrichtung

410

Anzeige des Fehlers

412

Initiierung des Leistungsbeschränkung-LOS-Modus mit niedriger Geschwindigkeit

414

Reaktivierung des VVC und der 2. Vorrichtung im Drehmomentbeschränkungsmodus (Überschrift zur Formel) „2nd Device“ = 2. Vorrichtung (Index zu klein Omega im Nenner der Formel)

416

Ist die 1. Vorrichtung immer noch ausgefallen oder deaktiviert?

420

Erhöhung des Leistungsbeschränkungszählers

432

Ist der Leistungsbeschränkung-Zeitzähler > Schwellenzeit?

434

Ausstieg aus der niedrigen Geschwindigkeit

436

Permanente Aufrechterhaltung des Drehmomentbeschränkungsmodus in der 2. Vorrichtung

424

Ausstieg aus dem Leistungsbeschränkung-LOS-Modus und aus der niedrigen Geschwindigkeit

426

Rückstellung des Leistungsbeschränkungszählers auf null

428

Reaktivierung der 1. und 2. Vorrichtung

N

Nein

Fig. 8

402

Control detects failure and disables the 1st device

404

Initiate the power-limit LOS mode at high speed

408

Temporary conversion of the VVC into shunt mode

406

Temporary deactivation of the second device

410

Display of the error

412

Initiate low power performance limit LOS mode

414

Reactivation of the VVC and the 2nd device in the torque limitation mode (heading to the formula) "2nd Device" = 2nd device (index too small omega in the denominator of the formula)

416

Is the 1st device still down or disabled?

420

Increase of the power restriction counter

432

Is the power restriction time counter> threshold time?

434

Exit from the low speed

436

Permanent maintenance of the torque limiting mode in the 2nd device

424

Exit from the power limit LOS mode and from the low speed

426

Reset the power restriction counter to zero

428

Reactivation of the 1st and 2nd device

N

No

Claims (5)

A method of controlling a hybrid electric vehicle, comprising: Deactivating an electric machine and a variable voltage converter (VVC) when the voltage of the electric machine exceeds an overvoltage threshold; and as soon as determining that the voltage of the electric machine has dropped to at least a second threshold, which is lower than the overvoltage threshold, reactivating the electric machine; and Set the VVC to a normal operating mode. The method of claim 1, further comprising reactivating the electric machine during a drive cycle. The method of claim 2, wherein deactivating the VVC comprises the electric machine limited operating mode, wherein the limited operating mode allows the vehicle to maintain the vehicle drive during the driving cycle. The method of claim 1, further comprising: Command the VVC to run in a mode in which a voltage is passed from a high voltage electrical connection to the battery to rapidly drain high voltage in response to the electric machine exceeding the overvoltage threshold. The method of claim 1, wherein in response to the electric machine exceeding the overvoltage threshold, the VVC is set to a mode that prevents the provision of a boost voltage to the at least one electric machine.

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