KR102644574B1 - Method for emergency driving of hybrid electric vehicle - Google Patents

Abstract

The present invention relates to an emergency driving method for a hybrid vehicle, and its main purpose is to provide an emergency driving method for a hybrid vehicle. In order to achieve the above object, battery voltage and inverter cap voltage information are acquired; Diagnosing a failure of a DC link circuit connecting the battery and the inverter using the acquired battery voltage and inverter cap voltage; turning off the PWM output to the inverter when the DC link circuit is in a fault state; After starting the engine, rotating the motor with engine power to generate back electromotive force in the motor; An emergency driving method for a hybrid vehicle is disclosed, including the step of driving an electric oil pump using the generated back electromotive force so that the vehicle can limp home.

Description

Method for emergency driving of hybrid electric vehicle}

The present invention relates to an emergency driving method for a hybrid vehicle, and more specifically, to an emergency driving method for a hybrid vehicle that can solve the problem of vehicle shutdown when a high-voltage component fails.

Hybrid electric vehicles (HEV/PHEV) are a wide range of electric vehicles that run on electric motors, and are vehicles that run using engines and motors as driving sources.

A typical powertrain type of a hybrid vehicle is a type that has an engine clutch between the engine and the motor, and FIG. 1 is a diagram illustrating the system configuration of a hybrid vehicle.

As shown, a TMED (Transmission Mounted Electric Device) type hybrid system is known in which the engine 1 and the motor 3 are connected through the engine clutch 2 and the transmission 4 is connected to the motor output side.

In addition, an inverter 105 for driving and controlling the motor 3, which is the driving source of the vehicle, is mounted on the vehicle, and the motor 3 is connected to the high voltage battery 101 in the vehicle through the inverter 105 to enable charging and discharging. do.

The inverter 105 converts the direct current (DC) current supplied from the battery 101 into alternating current (AC) when driving the motor and applies it to the motor 3 through the power cable, and generates it in the motor 3 during regenerative braking. It serves to charge the battery by converting the alternating current into direct current and supplying it to the battery 101.

The inverter 105 includes a capacitor (C) and a power module (105a), and the power module (105a) operates the PWM signal of a motor control unit (MCU), not shown, and the gate driving (Gate on/Off) of the gate driver. off) and includes a plurality of switching elements (S) that operate according to a signal.

Insulated gate bipolar transistors (IGBTs), which are power semiconductor devices capable of high-speed switching operations even at high power, are widely used as switching elements that make up the power module in a typical inverter.

In addition, the vehicle is equipped with a Hybrid Starter and Generator (HSG) 5, which is a motor (starter generator) that is connected to the engine 1 to transmit power and starts the engine or generates power using rotational force transmitted from the engine.

Although not shown in the drawing, the HSG 5 is also connected to the battery 101 through a separate inverter so that it can be charged and discharged.

In addition, the inverter 105 is connected to the battery 101 through a DC link circuit 102, and the DC link circuit 102 has a power relay assembly (PRA) 103 for regulating high voltage power. It is installed.

The power relay assembly 103 includes a plurality of high-voltage relays 104a and 104b that open and close the (+) power line and (-) power line of the DC link circuit 102 connected between the battery 101 and the inverter 105. ), and each high voltage relay (104a, 104b) is controlled on/off by a battery controller (Battery Management System, BMS).

More specifically, the power relay assembly 103 includes two high-voltage main relays, namely the main relay 104a of the (+) power line and the main relay 104b of the (-) power line, and the main relay 104b of the (+) power line. It is configured to include a precharge relay (104c) and a precharge resistor (104d) installed in a circuit that bypasses the main relay (104a).

In addition, high-voltage components are connected to the DC link circuit 102 connected to the high-voltage battery 101 so as to receive high-voltage power, for example, an air conditioner compressor 106 for vehicle air conditioning and a DC link circuit 102 for supplying oil to the transmission. An electric oil pump (EOP) 107 is connected to the DC link circuit 102, which is a high voltage path.

Meanwhile, in the event of a component failure or other emergency situation in the vehicle, the vehicle must be capable of limp home driving, and limp home driving provides minimum driving performance so that the vehicle can move to the shoulder or repair center in the event of a breakdown. There is a purpose to doing this.

If a controller failure or battery failure occurs in a hybrid vehicle, the high voltage components 106 and 107 connected to the DC link circuit 102 may not receive power.

In the following description, the high-voltage relay refers to the main relays 104a and 104b, and in the following description, battery failure includes battery overtemperature failure, off-state failure of the high-voltage relays 104a and 104b, and fuse 101a. ) This includes disconnection, VPD (Voltage Protection Device) (not shown) malfunction, etc.

In this battery failure state, the battery 101 power cannot be used, so the electric oil pump (EOP) 107 cannot be driven with battery power. However, for limp home driving of the vehicle, the electric oil pump 107 must be connected to another vehicle. It must be driven by electric power.

If the electric oil pump 107 is not operating, oil cannot be supplied to the transmission 4, so the vehicle enters a shutdown state and vehicle operation stops immediately.

Therefore, even if the electric oil pump 107 is not supplied with battery power, a method must be prepared to enable the electric oil pump to be driven and the vehicle to limp home.

Conventional hybrid vehicles are equipped with a low-voltage electric oil pump (EOP) and a separate mechanical oil pump (MOP) driven by engine power to generate hydraulic pressure in the hydraulic system.

In this case, even if the electric oil pump (EOP) cannot operate, hydraulic pressure can be generated and supplied using the mechanical oil pump (MOP), making limp home driving of the vehicle possible.

However, in recent TMED hybrid systems, only an oil pump unit (OPU) consisting of a high-voltage electric oil pump (EOP) 107 and a pump controller is provided, so malfunction or malfunction of the oil pump (EOP) may occur. If this is not possible, hydraulic pressure cannot be generated in the hydraulic system, and hydraulic pressure cannot be supplied from the transmission 4, making it impossible to drive the vehicle.

Therefore, there is a need for technology that can supply power to the electric oil pump (EOP) 107 even when a battery failure occurs.

In the high-voltage circuit system, the high-voltage oil pump unit (OPU) receives power from the battery due to component failure or quality problems, such as deterioration of the power relay assembly (PRA) (main relay off-state failure), blown fuse, or VPD malfunction. If it is not supplied, the performance of the oil pump deteriorates due to lack of voltage, making it unable to generate the required hydraulic pressure.

Therefore, it is possible to ensure driving performance and customer safety as much as possible by enabling limp home driving of the vehicle in situations where vehicle driving is impossible (vehicle shuts down immediately in case of failure) due to main relay off-state failure, fuse blowout, VPD malfunction, etc. A solution is required.

According to the prior art, in the case of a battery failure in which the battery controller (BMS) can recognize the failure state through a predetermined diagnostic process, for example, battery overtemperature failure, limp home driving of the vehicle is possible under cooperative control of the battery controller, etc. .

However, according to the prior art, cooperative control is not possible for battery failures such as main relay off-state failure, fuse blowout, or VPD malfunction because the battery controller (BMS) does not recognize the failure state.

Ultimately, if cooperative control is not possible, the DC link circuit 102, which is a high voltage path, is opened and the operating voltage of the electric oil pump (EOP) is not sufficiently supplied, so limp home driving of the vehicle is impossible and the vehicle is forced to shut down immediately. does not exist.

Figure 2 shows an example of enabling limp home driving of a hybrid vehicle through cooperative control in the event of a battery failure, and shows a case where the battery controller (BMS) recognizes the failure state when the battery fails.

Figure 2 shows the minimum operating voltage that can drive the electric oil pump (hereinafter referred to as 'EOP') 107, and when a battery failure (battery overtemperature failure, etc.) occurs, the engine is rotated after starting the engine for EOP operation. It shows that the RPM is increasing.

If a battery failure occurs in a vehicle, such as a battery overtemperature failure that the battery controller (BMS) can identify and recognize through a designated diagnostic process, the controllers within the vehicle, including the battery controller, cooperatively control and engage the engine clutch (2). After locking up and starting the engine (1), the motor (3) or HSG (5) can be rotated with engine power, and eventually EOP ( 107) can be operated.

In the case of a battery failure that can be recognized by the battery controller (BMS) and coordinated control can be performed, the operating power of the EOP (107) may be the back electromotive force of the motor (3) or the HSG (5).

During cooperative control for engine start, the battery controller (hereinafter referred to as 'BMS') transmits a failure signal to the upper controller, the Hybrid Control Unit (hereinafter referred to as 'HCU'), and the BMS transmits the engine control unit to the HCU. Request to start the engine.

Accordingly, the HCU controls the slip of the engine clutch 2 so that the rotational force of the driving wheel is transmitted to the engine 1 through the motor 3 to start the engine, and after the engine starts, the power of the engine 1 is transferred to the motor ( Completely engage the engine clutch (2) so that the transmission can be transmitted to 3).

Additionally, when the BMS recognizes a battery failure, it outputs a main relay off control signal, and the motor controller (hereinafter referred to as 'MCU') turns off the PWM output by referring to the main relay off control signal of the BMS.

The PWM output from the MCU for the inverter of the motor 3 and HSG 5 must be turned off so that back electromotive force can be generated when the motor 3 and HSG 5 are receiving power from the engine 1.

Ultimately, when the PWM of the MCU is in the OFF state after the engine starts, back electromotive force may be generated in the motor (3) or HSG (5) that receives the power of the engine (1), and this back electromotive force sets the minimum operating voltage to the EOP (107). Since the above voltage can be supplied, it is possible to secure the EOP operating voltage, drive the EOP and supply oil accordingly, and further enable limp home driving of the vehicle.

As a result, the controllable state of the pump controller within the OPU can be maintained, and EOP operation and control can be performed by the pump controller, allowing the vehicle to drive in limp home mode.

In this way, in the event of a battery-related failure, when the BMS recognizes the battery-related failure on its own, it can output a signal for cooperative control to other controllers, so it can output a main relay off control signal, and the MCU can then turn off the main relay. The PWM output can be turned off by referring to the signal, and eventually diode rectification driving using the back electromotive force of the motor (3) and HSG (5) is possible.

Referring to Figure 2, the BMS outputs the main relay off control signal ('Relay off'), the PWM output of the MCU is turned off ('MCU PWM off'), and the engine clutch 2 is locked up after engine start. It indicates the state (combined state) ('Lock up').

However, in the case of failures such as deterioration of the power relay assembly (PRA) 103 (main relay off state failure), disconnection of the fuse 101a, VPD malfunction, etc., the battery 101 is Since power is not supplied to the EOP (107), it is impossible to start the engine, secure the EOP operating voltage, and further coordinate control between controllers for limp home driving.

Ultimately, the EOP (107) does not continue to receive operating voltage and becomes inoperable, and hydraulic pressure is not supplied to the transmission (4), etc., resulting in a vehicle shutdown state in which limp home driving of the vehicle is impossible.

Figure 3 is a diagram showing a problem according to the prior art, showing a battery failure that the BMS cannot recognize.

In the case of an open failure of the DC link circuit, such as an off-state failure of the main relays 104a and 104b, a disconnection of the fuse 101a, or a VPD malfunction, cooperative control is not possible because the BMS does not recognize the failure.

As shown, when the BMS does not recognize a failure, the BMS does not output a relay off control signal, so PWM off in the MCU is not performed in time, and PWM off is performed in the MCU low voltage state.

However, since the BMS does not recognize the failure and does not perform cooperative control with other controllers, the engine cannot be started even after PWM is turned off, and the EOP operating voltage cannot be secured.

Ultimately, the state below the EOP minimum operating voltage (e.g., 80V) is maintained for a set time (e.g., 100 ms), resulting in a vehicle shutdown (HEV Ready off) state.

In this way, when the set time for which hydraulic pressure is not supplied to the transmission (4) is maintained under the EOP minimum operating voltage, the vehicle is shut down and control by the pump controller of the OPU and operation of the EOP (107) are disabled, resulting in limp home of the vehicle. Driving becomes impossible.

Therefore, the present invention was created to solve the above problems, and is an emergency driving method for a hybrid vehicle that can solve the conventional problem in which the vehicle is immediately shut down and limp home driving is not possible due to a fault condition such as a high-voltage relay opening. The purpose is to provide.

In order to achieve the above object, according to an embodiment of the present invention, there are steps of acquiring battery voltage and inverter cap voltage information; Diagnosing a failure of a DC link circuit connecting the battery and the inverter using the acquired battery voltage and inverter cap voltage; turning off the PWM output to the inverter when the DC link circuit is in a fault state; After starting the engine, rotating the motor with engine power to generate back electromotive force in the motor; and driving an electric oil pump using the generated back electromotive force to enable limp home driving of the vehicle.

Here, the motor may be at least one or two of a motor that drives the vehicle and a motor that starts the engine.

In addition, in the step of diagnosing a failure of the DC link circuit, the difference between the acquired battery voltage and the inverter cap voltage is compared with a set value, and if the difference is greater than the set value, it is considered an open failure of the DC link circuit. You can judge.

Additionally, in a failure state of the DC link circuit, if the voltage of the electric oil pump is lower than a predetermined minimum operating voltage for more than a preset maintenance time, the vehicle can be shut down.

In addition, in a failure state of the DC link circuit, when the voltage of the electric oil pump is lower than a predetermined minimum operating voltage, turning off the PWM output, generating the back electromotive force, and limp home driving Steps to make this happen can be implemented.

Preferably, in a failure state of the DC link circuit, when the voltage of the electric oil pump becomes lower than a predetermined minimum operating voltage and a preset time elapses, turning off the PWM output, so that the counter electromotive force is generated. The step of performing the limp home travel may be carried out.

In addition, in the step of generating the back electromotive force, it is determined whether the current vehicle speed detected by the vehicle speed detection unit is higher than the set vehicle speed, and if the current vehicle speed is higher than the set vehicle speed, the engine clutch located between the engine and the vehicle driving motor is slipped. By controlling the rotational force of the vehicle's driving wheels to be transmitted to the engine through the motor and engine clutch, the engine can be started.

Here, after the engine is started, the engine clutch is completely engaged so that the power of the engine is transmitted to the vehicle driving motor, thereby generating back electromotive force for driving the electric oil pump in the vehicle driving motor.

In addition, if the current vehicle speed is lower than the set vehicle speed, in a failure state of the DC link circuit, and if the voltage of the electric oil pump is lower than the set minimum operating voltage for more than a set maintenance time, the vehicle may be shut down.

Accordingly, according to the emergency operation method of a hybrid vehicle according to the present invention, when it is determined that the DC link circuit is in an open failure state based on the battery voltage and the inverter cap voltage, the PWM output to the inverter is turned off and the engine is operated through engine clutch slip control. After starting, the motor is rotated by engine power, and the electric oil pump is driven by the back electromotive force generated by the motor, thereby enabling limp home driving of the vehicle.

Figure 1 is a diagram illustrating the system configuration of a hybrid vehicle.
Figure 2 is a diagram illustrating a control state that enables limp home driving of a hybrid vehicle through cooperative control in the event of a battery failure.
Figure 3 is a diagram showing problems according to the prior art.
Figure 4 is a flowchart showing an emergency operation process according to an embodiment of the present invention.
Figure 5 is a diagram showing a control state in which limp home driving of a vehicle is achieved through cooperative control during an emergency operation according to an embodiment of the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

The present invention relates to an emergency driving method for a hybrid vehicle, which provides cooperative control and limp home driving in the case of a failure that the battery controller (BMS) does not recognize, such as a main relay off state failure, fuse blowout, or VPD malfunction. We aim to provide an emergency driving method for hybrid vehicles that can solve the problem of the vehicle shutting down immediately due to impossibility, enable limp home driving, secure driving performance in emergency situations, and improve the safety of drivers and passengers. It is done.

In the following description, reference will be made to FIG. 1 for the system configuration.

In addition, the emergency operation method according to the present invention involves cooperative control by a plurality of controllers, such as a hybrid controller (hereinafter referred to as 'HCU'), a battery controller (hereinafter referred to as 'BMS'), and a motor controller (hereinafter referred to as 'MCU'). It can be performed or performed by a single integrated controller. Hereinafter, the emergency operation process according to the present invention will be described as an example in which a plurality of controllers cooperatively control the emergency operation process.

The main cause of the above-described conventional problem is that the BMS does not recognize battery failures such as the off-state failure of the high-voltage main relays 104a and 104b, disconnection of the fuse 101a, and VOP (not shown) malfunction.

Therefore, in the present invention, the DC link circuit 102 connecting the battery and the inverter is open due to the off-state failure of the main relays 104a and 104b, disconnection of the fuse 101a, VOP malfunction, etc. By using a method that can indirectly confirm that the engine is started, the operating voltage of the electric oil pump is secured, and the controllers for limp home driving of the vehicle can be cooperatively controlled.

If the high-voltage DC link circuit 102 is in an open state due to the above failure, it is impossible to operate the electric oil pump (hereinafter referred to as 'EOP') 107 using battery power, and at this time, the hydraulic pressure is Since it cannot be supplied to powertrain parts such as the transmission (4), the vehicle may ultimately be unable to limp home and the vehicle may be shut down.

In the present invention, if the main relays 104a and 104b or the fuse 101a deteriorate and an abnormality occurs in the DC link circuit 102, which is a high voltage path, a difference between the battery voltage and the inverter cap voltage actually occurs. , the difference between the voltages at two points is used to indirectly diagnose whether the DC link circuit is in an open failure state due to a main relay off-state failure or fuse blowing.

Here, the battery voltage and the inverter cap voltage are both voltage measurement values detected and measured by the voltage detection unit. The inverter cap voltage refers to the MCU DC link voltage, and in normal cases, the MCU determines the inverter cap voltage value from the signal of the voltage detection unit. is acquired as real-time voltage information.

In addition, the battery voltage is real-time voltage information acquired from the BMS from the signal of the voltage detector, and when the MCU transmits the inverter cap voltage information to the BMS, the BMS compares the two voltages and calculates the difference between the two voltages, that is, the voltage difference. Then, from the voltage difference, it is possible to diagnose whether the DC link is open due to a main relay off-state failure, fuse blowout, or VPD malfunction.

Figure 4 is a flowchart showing an emergency driving method according to an embodiment of the present invention. With reference to this, the process of cooperative control for emergency driving (i.e., limp home driving) will be described step by step.

First, while the vehicle is in operation, the controllers in the vehicle acquire real-time voltage information from the signal of the voltage detector (S11). At this time, the BMS acquires information about the battery voltage, and the MCU acquires information about the inverter cap voltage.

Additionally, the pump controller of the oil pump unit (hereinafter referred to as 'OPU') acquires information about the EOP voltage.

At this time, the MCU transfers the inverter cap voltage information acquired in real time to the BMS, and the BMS compares the battery voltage and the inverter cap voltage and calculates the difference between the two voltages, that is, the voltage difference between the two points of the battery and the inverter cap.

Next, the BMS compares the voltage difference with a predetermined set value (S12), and if the voltage difference is less than the set value, it determines that a DC link open failure has not occurred and determines the vehicle's driving state without cooperative control for limp home driving. Keep it as is (S13).

On the other hand, when the voltage difference exceeds the set value, the BMS determines that the DC link circuit 102 is in an open fault state, which may be caused by a main relay off state failure, fuse blowing, or VPD malfunction (S14).

In this way, when the off-state failure of the main relays 104a and 104b, the disconnection of the fuse 101a, or other malfunction of the VPD (not shown) occur, the failure is determined by comparing the voltage difference between the two points with the set value. As a result, it can be determined that the DC link circuit 102 is in an open state, a DC link open failure state.

Once the DC link circuit 102, which is a high voltage path, is opened due to a failure, the voltage of the OPU also drops, so the voltage of the OPU, especially the voltage at EOP (hereinafter referred to as 'EOP voltage'), is lower than the predetermined EOP minimum operating voltage. It can be in a lower state.

In the present invention, if the EOP voltage is lower than the minimum operating voltage and continues for more than a preset maintenance time, the vehicle can be shut down immediately (S15, S16). At this time, when information about the EOP voltage is transmitted from the pump controller to the HCU, the HCU It can be set to determine whether to shut down the vehicle using the EOP voltage, the set minimum operating voltage, and the set maintenance time.

That is, if the EOP voltage is lower than the set minimum operating voltage continues for the set maintenance time, the HCU performs control for vehicle shutdown.

Accordingly, until vehicle shutdown is determined, that is, until the EOP voltage is lower than the minimum operating voltage reaches the above maintenance time, after starting the engine, the motor that drives the vehicle with engine power and the HSG, which is the motor that starts the vehicle, At least one of them must generate back electromotive force so that a voltage higher than the minimum operating voltage can be supplied to the EOP.

Therefore, in the emergency operation process according to the present invention, when the pump controller transmits information about the EOP voltage to the HCU, it is set to simultaneously transmit information about the EOP voltage to the BMS.

Accordingly, when the BMS determines that the DC link is in an open failure state, it can be determined whether the EOP voltage is lower than the set EOP minimum operating voltage from information about the EOP voltage received from the pump controller.

Then, when it is determined that the EOP voltage is lower than the EOP minimum operating voltage, the BMS begins cooperative control with other controllers to start the engine, secure the EOP operating voltage, and drive the vehicle limp home.

Preferably, after the BMS determines that the EOP voltage becomes lower than the EOP minimum operating voltage, it counts the time from that point to determine whether the set time has elapsed (S17). If the set time has elapsed, the BMS starts the engine and It can be set to secure the EOP operating voltage and initiate cooperative control for vehicle limp home driving.

That is, if the EOP voltage becomes lower than the EOP minimum operating voltage and the set time has elapsed, the BMS transmits the main relay off control signal to the MCU (S18), and the MCU turns off the PWM output for the inverter 105 (S19). ).

Additionally, if the set time has elapsed after the EOP voltage becomes lower than the EOP minimum operating voltage, the BMS transmits a failure signal to the HCU and requests engine start (S20).

Here, the setting time is set to a time shorter than the holding time.

Accordingly, when the HCU receives a failure signal and an engine start request, it determines whether the current vehicle speed detected by the vehicle speed detection unit is higher than the set vehicle speed (S21). If it is determined that the current vehicle speed is higher than the set vehicle speed, the engine control unit (Engine Control Unit) , hereinafter referred to as 'ECU') and cooperative control for engine start (S21, S23).

At this time, the HCU controls the slip of the engine clutch 2 (S22) and ensures that fuel is supplied to the engine 1 through cooperative control with the ECU. This allows the rotational force of the driving wheel to be transferred to the transmission 4 and the motor 3. , the engine can be started while being transmitted to the engine 1 through the engine clutch 2 (S23).

After the engine (1) is started, the HCU completely locks up the engine clutch (2) so that the power of the engine (1) can be transmitted to the motor (3) (S24), thereby and HSG (5) are rotated by engine power, generating back electromotive force.

In this way, the back electromotive force generated by the motor and the HSG is applied to the OPU, causing the OPU voltage to rise again, and eventually, a voltage higher than the minimum operating voltage is supplied to the EOP, thereby ensuring the EOP operating voltage (S25).

Accordingly, the EOP can operate, and eventually, hydraulic pressure can be supplied to powertrain components such as the transmission by the EOP operation, and limp home driving of the vehicle can be achieved (S26).

However, if the current vehicle speed is lower than the set vehicle speed in step S21, the engine cannot be started with the rotational force of the driving wheel even if the engine clutch is slip controlled, so the HCU inevitably maintains the EOP voltage lower than the EOP minimum operating voltage for the maintenance time. In this case, the vehicle is shut down (S15, S16).

In the above explanation, the BMS receives information about the EOP voltage from the OPU (pump controller) and determines that the EOP voltage is lower than the EOP minimum operating voltage, and the HCU also receives information about the EOP voltage from the OPU and transfers the EOP to the EOP. Although it has been explained that it is determined to be lower than the minimum operating voltage, it is possible to have this process performed in the OPU.

That is, when the EOP voltage in the OPU becomes lower than the EOP minimum operating voltage, the OPU simultaneously transmits a signal indicating that the EOP voltage is lower than the EOP minimum operating voltage to the BMS and HCU, and the BMS sends a main relay off control signal to the MCU. to send it.

In addition, when the HCU also receives a signal from the OPU indicating that the EOP voltage is lower than the EOP minimum operating voltage, it counts the subsequent time, and when the current vehicle speed is lower than the set vehicle speed, the EOP voltage is lower than the EOP minimum operating voltage. If it continues longer than the holding time, the vehicle can be shut down.

In this way, according to the emergency operation method according to the present invention, even if the BMS does not recognize the failure state through the existing diagnostic logic, if the difference between the battery voltage and the inverter cap voltage is greater than the set value, the main relay is in the off state, the fuse is It is determined to be in a malfunction state due to a disconnection, VPD malfunction, etc., and cooperative control for engine start, securing EOP operating voltage, and limp home driving is performed, thereby enabling emergency operation of the vehicle (limp home driving).

In the past, if the BMS did not recognize a fault condition due to a main relay off-state failure, fuse blowout, VPD malfunction, etc., and the EOP operating voltage was not secured in time and the vehicle was shut down while the EOP voltage was lower than the minimum operating voltage, the OPU Even though the EOP was normal, there were many cases of incorrect replacement during A/S.

However, in the present invention, by diagnosing the DC link open failure state, it is possible to accurately determine the problem part, such as the main relay, and thus accurately replace the problem part, so that the OPU or EOP that is in a normal state is unnecessary and incorrectly replaced as in the past. This can be prevented, and ultimately, there are various benefits such as reduced A/S costs, improved diagnostic reliability, and improved vehicle marketability.

Figure 5 is a diagram showing a control state in which limp home driving of a vehicle is achieved through cooperative control in an emergency operation process according to an embodiment of the present invention, which is explained as follows.

As shown, if a DC link open failure occurs due to a battery failure, especially a main relay off-state failure, fuse blowout, or VPD malfunction, the EOP voltage may gradually decrease and fall below the EOP minimum operating voltage.

At this time, the BMS cannot detect a DC link open failure through the existing diagnostic process, but in the present invention, it is possible to determine whether a DC link open failure is detected by comparing the battery voltage and the inverter cap voltage and determining whether the voltage difference is greater than the set value. You can.

Ultimately, after determining that the DC link is in an open failure state and the EOP voltage becomes lower than the EOP minimum operating voltage, it is determined whether the set time ('X seconds') has elapsed after the EOP voltage becomes lower than the EOP minimum operating voltage. , When the set time has elapsed, the BMS' relay off control signal output ('Relay off'), the MCU's PWM off ('MCU PWM off'), and the HCU's engine clutch slip control and lock-up ('Lock up') control are performed. Afterwards, the vehicle is driven to limp home with the engine starting and OPU control enabled.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements can be made by those skilled in the art using the basic concept of the present invention as defined in the following patent claims. It is also included in the scope of rights of the present invention.

1: engine
2: Engine clutch
3: motor
4: Transmission
5:HSG
101: battery
101a: fuse
102: DC link circuit
103: Power relay assembly (PRA)
104a, 104b: main relay
104c: Precharge relay
104d: Precharge resistance
105: inverter
105a: Power module
106: Air conditioner compressor
107: Electric oil pump (EOP)
C: Capacitor
S: switching element

Claims (9)

Obtaining battery voltage and inverter cap voltage information;
Diagnosing a failure of a DC link circuit connecting the battery and the inverter using the acquired battery voltage and inverter cap voltage;
turning off the PWM output to the inverter when the DC link circuit is in a fault state;
After starting the engine, rotating the motor with engine power to generate back electromotive force in the motor; and
It includes a step of driving the electric oil pump by the generated back electromotive force to enable limp home driving of the vehicle,
In a failure state of the DC link circuit, when the voltage of the electric oil pump is lower than the predetermined minimum operating voltage, turning off the PWM output, generating the back electromotive force, and performing the limp home run. An emergency driving method for a hybrid vehicle, characterized in that steps are performed to ensure that the vehicle is safe.
In claim 1,
An emergency driving method for a hybrid vehicle, wherein the motor is at least one or two of a motor that drives the vehicle and a motor that starts the engine.
In claim 1,
In the step of diagnosing a failure of the DC link circuit,
An emergency driving method for a hybrid vehicle, comprising comparing the obtained difference between the battery voltage and the inverter cap voltage with a set value, and determining that the DC link circuit is open failure if the difference is greater than the set value.
In claim 1,
An emergency driving method for a hybrid vehicle, characterized in that, in a failure state of the DC link circuit, if the voltage of the electric oil pump is lower than a predetermined minimum operating voltage for more than a preset maintenance time, the vehicle is shut down.
delete In claim 1,
In a failure state of the DC link circuit, turning off the PWM output when a preset time has elapsed after the voltage of the electric oil pump becomes lower than a predetermined minimum operating voltage, generating the counter electromotive force, and An emergency driving method for a hybrid vehicle, characterized in that the step of enabling the limp home driving is performed.
In claim 1,
In the step of generating the counter electromotive force,
Determine whether the current vehicle speed detected by the vehicle speed detection unit is greater than or equal to the set vehicle speed,
When the current vehicle speed is higher than the set vehicle speed, the engine clutch located between the engine and the vehicle driving motor is controlled to slip, so that the rotational force of the vehicle driving wheel is transmitted to the engine through the motor and engine clutch to enable engine start. How to drive an emergency hybrid vehicle.
In claim 7,
After starting the engine, the engine clutch is completely engaged so that the power of the engine is transmitted to the vehicle driving motor, and the vehicle driving motor generates back electromotive force for driving the electric oil pump. How to drive.
In claim 7,
If the current vehicle speed is lower than the set vehicle speed, the DC link circuit is in a fault state, and the voltage of the electric oil pump is lower than the set minimum operating voltage for more than a set maintenance time, the hybrid is characterized in that the vehicle is shut down. How to drive your vehicle in an emergency.

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