KR101470098B1 - Fault diagnosis system and method for relay of vehicle - Google Patents

Abstract

The present invention relates to an apparatus and method for diagnosing a relay failure of a vehicle, and more particularly, to an apparatus and method for diagnosing a relay failure of a vehicle, in which an environmentally-friendly vehicle such as an electric car or a hybrid vehicle The present invention provides an apparatus and a method for diagnosing a disease. It is another object of the present invention to provide an apparatus and method for diagnosing whether or not a quick-charge relay is fused in a vehicle. According to an aspect of the present invention, there is provided a fault diagnosis apparatus comprising: a power supply circuit unit for applying a voltage for diagnosis of a fault; A first resistor connected between both ends of the contact of the relay to be diagnosed and connected to the ground terminal; A second resistor connected in series between the power supply circuit portion and the first resistor; A converter for converting a voltage signal applied to both ends of the second resistor in a state where a voltage is applied through the second resistor from the power supply circuit to a digital signal form; And a CPU for determining whether or not the relay is welded from a voltage signal in the form of a digital signal output from the converting unit. Here, the relay to be diagnosed may be either the main relay, the precharge relay, the rapid charging relay, or two or more relays.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for diagnosing a relay failure of a vehicle, and more particularly, to an apparatus and a method for diagnosing whether or not a high voltage relay, a rapid charging relay and the like are fused in an environmentally friendly automobile such as an electric car or a hybrid car .

Today, development of eco-friendly automobiles capable of replacing existing internal combustion engine automobiles due to high oil prices and carbon dioxide regulations is actively under way. Recently, pure electric vehicles that drive electric motors or electric motors and electric motors are used together as driving sources Hybrid cars are already commercialized according to the automobile manufacturers, or they are in the process of being commercialized.

BACKGROUND ART An electric vehicle or a hybrid vehicle is equipped with a high voltage battery as a main power source for supplying electric power to an electric motor serving as a driving source and a charging device for charging the battery and an electric motor And the like.

The inverter drives a driving motor by phase-converting a power supplied from a high-voltage battery according to a control signal of a motor control unit (MCU).

In addition, a battery management system (BMS) for monitoring the state of the battery is mounted. The battery controller collects battery state information on the battery temperature, voltage, charge / discharge current, battery state of charge (SOC) , And provides collected battery status information to another controller in the vehicle so that it can be used for vehicle control.

Particularly, the battery controller checks the state of the battery to manage the state of the battery to a predetermined level or higher, thereby preventing the life span of the battery from being shortened due to the degradation of battery durability and informing the SOC information of the battery to the vehicle controller performing the total control, So that the vehicle can be driven.

On the other hand, Fig. 1 is a diagram showing a high voltage circuit portion applied to a conventional electric vehicle or a hybrid vehicle, and schematically illustrates the configuration and connection state of a high voltage circuit portion (each component and a high voltage wire).

The illustrated high voltage circuit includes a high voltage battery 10 as a power source for the vehicle, a drive motor 40 driven by the power of the high voltage battery 10, an inverter 31 for driving the drive motor 40 And a power relay assembly (PRA) 20 for switching the battery power to be selectively supplied to the vehicle.

Here, the motor controller 30 controls the driving of the switching elements in the inverter 31 so that the DC voltage is converted to the three-phase power via the inverter so that the phase current can be applied to the driving motor 40 side.

The motor controller 30 includes a capacitor C that is installed at a DC link end and charged by a voltage supplied from the battery 10. [

The power relay assembly 20 is installed to selectively open and close battery power on a high voltage circuit connecting the DC link ends of the battery 10 and the motor controller 30. The power relay assembly 20 includes a plurality of high voltage relays 21, 23).

The power relay assembly 20 includes two high voltage main relays 21 and 22 which are main power contacts and a precharge relay 22 which is installed on a circuit that bypasses one of the two main relays 21 and 22, ) 23 and a precharge resistor (24).

1, a first main relay 21 is provided on the circuit between the (+) terminal and the (+) terminal of the battery 10 and the (-) terminal of the battery 10 The second main relay 22 is provided on the circuit between the DC link (-) terminal and the pre-charge relay 23 and the pre-charge resistor 24 are provided on the bypass circuit bypassing the first main relay 21, Respectively.

The relays of the power relay assembly 20 are usually controlled to be on / off according to a relay control signal output from a battery controller (BMS) 50 or a motor controller (MCU)

In the meantime, the above-mentioned relays have a problem of fusing, and an algorithm for checking the fusion of these relays is applied. When fusion occurs in the relays, even in the case of IG off (e.g., parking) High voltage is continuously exposed and dangerous situations such as electric shock may occur.

More specifically, first, the contacts of the relay are composed of a fixed contact and a moving contact. Due to the arc generated between the fixed contact and the driving contact, the two contacts are stuck to each other, A state in which no OFF control is performed is referred to as welding.

In the case where, for example, the first main relay 21 is fused to any of the two main relays 21 and 22 in the vehicle to which the two main relays 21 and 22 are applied, The contact of the first main relay 21 in which fusing has occurred does not fall off even in the IG off state, which is supposed to be the OFF state.

If the relay control becomes ineffective as described above, the function / purpose inherent to the high voltage can not be achieved. Secondary accidents such as electric shock and fire are inevitable as well as the primary accident due to the inability to secure insulation in case of an accident such as a collision.

For example, if the OFF control of the relays 21 and 22 is impossible due to the contact fusion in the IG off state, a dangerous situation such as electric shock may occur because the high voltage DC component is exposed to the outside. Is exposed to the outside, a high-voltage battery and an electric closed loop via the human body are formed to conduct electric current, so that the human body is exposed to various types of electric shock.

That is, there is a risk of electric shock in the direct contact state where the human body touches the high voltage (+) and (-) terminals at the same time, or in the case where the human body touches either terminal in the body- The risk of electric shock in contact with direct / indirect contact, or the risk of electric shock in indirect contact, in which a human body touches an insulation-breakdown high-voltage part under the body-to-wire insulation breakdown condition or contacts two insulation breakdown high-voltage parts at the same time have.

Therefore, in order to prevent the risk of electric shock, it is necessary to provide a relay on sequence in which the precharge relay 23 and the main relays 21 and 22 are sequentially turned on at the time of IG on, It is necessary to check whether or not the main relays are fused in a relay off sequence (Off Sequence) in which the main relays 21 and 22 are sequentially turned off at the time of off.

FIG. 3 is a diagram for explaining a conventional method for checking whether or not main relays are fusion-bonded in an on-off sequence.

First, the controller 50 (e.g., a battery controller) detects the IG on input and outputs a relay control signal (of a relay on sequence) for starting up, in which the precharging of the capacitor C The contacts of the second main relay 22 and the precharge relay 23 are switched on.

At this time, the second main relay 22 is first turned on and then the precharge relay 23 is turned on. The elapsed time from turning on the second main relay 22 to turning on the precharge relay 23 The time is defined as 't1' as shown in FIG.

Since the supply path of the battery power is formed only when the second main relay 22 and the precharge relay 23 are both turned on, the capacitor C in the motor controller 30 is charged by the current supplied from the high voltage battery 10 And eventually the inverter voltage (detected by the voltage sensor 32), which is the voltage of the DC link stage, rises.

Therefore, during the time t1 before the second main relay 22 is turned on and before the precharge relay 23 is turned on, particularly at the moment when the contact of the second main relay 22 is applied, the precharge relay 23 is turned on The first main relay 21 is judged to be in a fused state when the inverter voltage abnormally rises.

When the capacitor C is charged to a predetermined level, the contact of the first main relay 21 is switched on and the contact of the precharge relay 23 is switched off.

Here, the elapsed time until the first main relay 21 is turned on after the precharge relay 23 is turned on is defined as 't2' as shown in FIG. 3, and the on time of the first main relay 21 And the elapsed time from the time point of the precharge relay 23 to the time point of turning off the precharge relay 23 is defined as 't3'.

The controller 50 detects the IG off signal and outputs a relay control signal for the start-off (in the relay-off sequence). In this off-sequence, the contact of the second main relay 22 is first turned off, After the inverter voltage falls, the contact of the first main relay 21 is turned off.

At this time, an elapsed time from the time of turning off the second main relay 22 to the time of turning off the first main relay 21 is defined as 't4' as shown in FIG. 3, and the second main relay 22 is turned off The inverter voltage must be lowered for t4 hours. If the inverter voltage does not fall even though the second main relay 22 is turned off while the first main relay 21 is still on, the contact of the second main relay 22 That is, the second main relay is in a fusion state.

FIG. 3 is a view for explaining another conventional method, and a method of performing the fusion checking process of the first main relay 21 and the second main relay 22 in the relay-on sequence may be used.

The main relay 22 and the first main relay 21 are sequentially controlled in the sequence of the precharge relay 23, the second main relay 22 and the first main relay 21 in the ON sequence. If the inverter voltage abnormally rises during the time t11 after the precharge relay- 2 main relay 22, it can be diagnosed that the second main relay is welded.

If the first main relay 21 is welded during the time t12 after the second main relay 22 is turned on, the inverter voltage will increase steadily without increasing gradually. Therefore, the abrupt increase of the inverter voltage is confirmed, It is possible to diagnose whether or not the welding is performed.

2 and 3, the battery controller (BMS) 50 receives the inverter voltage (detected by the voltage sensor), that is, the capacitor voltage behavior of the inverter from the motor controller (MCU) Signal to judge whether or not the relay is fused.

Therefore, if the battery controller can not receive the inverter voltage from the motor controller as the CAN signal, there is a problem that the relay fusion diagnosis becomes impossible.

In addition, if there is a quick-charge relay, it is impossible to diagnose whether or not the fast-charge relay is fused in the vehicle because the quick charger system (QCS) It is impossible to know the DC voltage behavior of the rapid charger in the vehicle.

4 is a circuit diagram in which the vehicle is connected to the rapid charger. As shown in Fig. 4, the vehicle is connected to a quick charger 60 for opening and closing a circuit between a high voltage line (a positive (+ Relays 51a and 51b, and each rapid charging relay is on / off controlled by a relay control signal applied from the battery controller 50. [

In this configuration, since there is no means for measuring the DC voltage of the rapid charging device in the conventional vehicle, it is impossible to diagnose whether or not the fast charging relay is fused in the vehicle.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an apparatus and a method for diagnosing whether or not a high-voltage relay is fused, without receiving an inverter voltage (a capacitor voltage of a motor controller) .

It is another object of the present invention to provide an apparatus and method for diagnosing whether or not a rapid charging relay is fused in a vehicle.

In order to achieve the above object, the present invention provides a power supply circuit comprising: a power supply circuit unit for applying a voltage for diagnosis of a fault; A first resistor connected between both ends of the contact of the relay to be diagnosed and connected to the ground terminal; A second resistor connected in series between the power supply circuit portion and the first resistor; A converter for converting a voltage signal applied to both ends of the second resistor in a state where a voltage is applied through the second resistor from the power supply circuit to a digital signal form; And a CPU for determining whether or not the relay is welded from a voltage signal in the form of a digital signal input from the converting unit.

In a preferred embodiment, the circuit further includes a circuit opening / closing switch provided on each circuit connecting between both ends of the first resistor and the respective contacts of the relay and being turned on / off in accordance with a control signal of the CPU.

And the relay to be diagnosed is a quick-charge relay of the vehicle for opening and closing a circuit between the DC link stage and the rapid charger between the battery and the motor controller.

Further, the relay to be diagnosed is any one of a first main relay, a second main relay, and a precharge relay installed at the DC link end between the battery and the motor controller, or each relay.

Also, when the voltage across the second resistor input from the conversion unit is different from the set steady-state voltage due to the formation of the current path leading to the ground via the contact of the second resistor and the relay, Is set to be determined.

And the normal voltage value is set to a voltage across the second resistor when a current path is formed from the first resistor and the second resistor to the ground terminal in a state where no relay fusion occurs.

According to another aspect of the present invention, there is provided a semiconductor integrated circuit device including a power supply circuit unit, a first resistor connected between both ends of a contact of a relay to be diagnosed and connected to a ground terminal, a second resistor connected in series between the power supply circuit unit and the first resistor, There is provided a method for performing a relay fault diagnosis in a relay fault diagnosis apparatus including a converter for converting a voltage signal applied to both ends of a resistor into a digital signal form and a CPU for receiving a voltage signal in the form of a digital signal outputted from the converter Applying a voltage for fault diagnosis through the second resistor from the power supply circuit unit; Converting the voltage signal applied to both ends of the second resistor into a digital signal and outputting the digital signal; And a step of the CPU judging whether or not the relay is fused from the voltage signal inputted from the converting unit.

Thus, according to the relay fault diagnosis apparatus and method of the present invention, it is possible to diagnose whether or not the relay is fused by using a simple voltage detection circuit that measures a voltage applied to the resistor connected to the relay without receiving the inverter voltage. Also, when the apparatus of the present invention is applied to an in-vehicle rapid charging relay, it is possible to diagnose whether or not the fast charging relay is fused even in a vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the configuration of a high voltage circuit portion applied to a conventional electric vehicle or a hybrid vehicle. FIG.
FIG. 2 is a diagram for explaining a conventional method for checking whether main relays are fused in an on / off sequence.
3 is a diagram showing a relay operation sequence.
4 is a diagram showing a rapid charge relay.
5 is a circuit diagram of a relay fault diagnosis apparatus according to the present invention.
6 is a diagram showing an overall circuit configuration to which a relay fault diagnosis apparatus according to the present invention is applied.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be easily understood by those skilled in the art.

5 is a circuit diagram of a relay fault diagnosis apparatus according to the present invention.

6 is a diagram showing a circuit configuration to which a relay fault diagnosis apparatus according to the present invention is applied, and shows in detail the configuration of a fault diagnosis circuit in a controller including a voltage detection circuit.

As shown in the drawing, a simple circuit composed of resistors R1 and R2 and switches S1 and S2 is added to the in-vehicle controller 50 to diagnose whether or not the relay is fused.

More specifically, the ground resistance, that is, the first resistor R1 connected to the ground terminal is connected between the terminals of the relays (21, 22, 23, 51a and 51b in FIG. 5) S1 and S2 are arranged on the respective circuits connecting both ends of the switches R1 and R1 and the respective contacts of the relays 21, 22, 23, 51a and 51b.

A second resistor R2 is connected in series between the power supply circuit portion 52 of the controller 50 and the first resistor R1 and both ends of the second resistor R2 are connected to the analog signal output portion 56 (ADC) 53 in the controller 50 so that the voltage across the second resistor R2 can be input to the converter 53 in the form of an analog signal.

The voltage signal of the analog signal type input to the conversion unit 53 is converted into a digital signal and input to the CPU 54 of the controller 50. The CPU 54 compares the voltage applied to the second resistor R2, The voltage signal in the form of a digital signal output from the conversion section 53 is read to diagnose whether or not the relays 21, 22, 23, 51a and 51b are fused.

In the circuit configuration described above, the relay may be a rapid charging relay 51a, 51b of the vehicle for opening and closing the circuit between the high voltage DC link stage of the vehicle and the rapid charger while the vehicle is connected to the rapid charger 60.

The relay may be a high voltage relay of the vehicle, that is, a first main relay 21 and a second main relay 22, a precharge relay 23, and may be any one of these high voltage relays or two or more relays .

In order to allow the vehicle to determine whether or not the first main relay 21, the second main relay 22, the precharge relay 23 and the quick-charge relays 51a and 51b are fusion-welded, The voltage detecting circuit 50 shown in FIG. 5 is constructed in the same manner for each relay, so that the controller 50 of the vehicle can confirm whether or not the resin is fused to some or all of the relays.

The controller 50 may be a battery controller and the switches S1 and S2 provided on the circuit between the resistors R1 and R2 and the relays 21 and 22, A semiconductor switch such as an FET, which is on / off controlled in accordance with a control signal output from the CPU 54, can be used.

5, the controller (50 in Fig. 6) turns on the switches S1 and S2 while turning off the relays 21, 22, 23, 51a and 51b, and a predetermined diagnostic voltage is applied to the first resistor R1 and the second resistor R2 in the ON state of the switch and then the output voltage value across both ends of the second resistor R2 is read.

The second resistor R2 and the switch S1 and the relays 21, 22, 23, 51a, and 51b are connected to each other in a state where the relay is fused. In this case, The switch S2, and the ground terminal are formed.

On the other hand, in a normal state in which the relays 21, 22, 23, 51a, and 51b are not fused, the relay is in an off state, so that a current path is formed from the first resistor R1 to the second resistor R2 and the ground terminal.

Due to the difference in the current paths, a difference in the output voltage value across the second resistor R2 occurs depending on the fusion state and the steady state of the relays 21, 22, 23, 51a, and 51b, It is possible to determine whether the relay 51a is fused by reading the measured voltage, that is, the output voltage value applied to the second resistor R2.

That is, the CPU 54 determines that the current path leading to the ground terminal through the contact of the second resistor R2 and the relays 21, 22, 23, 51a, and 51b due to actual relay fusion When the voltage across the second resistor R2 inputted from the converting unit 53 is different from the predetermined voltage value, it is determined that the relay is in a fused state.

Here, the steady-state voltage value is a voltage value across both ends of the second resistor R2, which is generated when a current path connecting the first resistor R1 and the second resistor R2 to the ground terminal is formed, , And the normal voltage value is previously inputted and set in the CPU 54 to judge whether or not the welding is performed.

When the measurement is completed as described above, the controller 50 turns off the switches S1 and S2 to open the circuit.

6 shows an embodiment for performing a fault diagnosis for the rapid charging relays 51a and 51b and includes two rapid charging relays 51a and 51b connected to the high voltage DC link (+) terminal and the (- A voltage detection circuit having the same configuration including a distribution resistor and a switch is provided.

Of course, although not shown in the drawings, the controller 50 may be configured to perform a fault diagnosis for the first main relay 21, the second main relay 22, and the precharge relay 23 as described above, A voltage detection circuit of the same configuration as that of FIG.

That is, for each relay of the first main relay 21, the second main relay 22 and the precharge relay 23, each of the voltage detection circuits 56 having the same configuration including the first resistor, 6, the first main relay 21, the second main relay 22, and the precharge relay 23 are provided in the conversion unit (ADC) 53 as shown in FIG. 6, So that the voltage signal across both ends of the second resistor can be input.

6, the power supply circuit portion 52 of the controller 50 is connected to apply a predetermined voltage for fault diagnosis through the second resistor R2, and detects the voltage applied to the second resistor R2 (ADC) 53 via the analog signal output section 56. The ADC 51 is connected to the analog signal output section 56 via the second resistor.

In this configuration, when a voltage is applied from the power supply circuit portion 52 to the second resistor R2 after the relay is turned off and the switch is turned on, the analog voltage output from the analog signal output portion 56 and the conversion portion 53 The CPU 54 can check the measured voltage information converted into the digital signal and determine whether the relay is welded or not.

Thus, in the fault diagnosis apparatus according to the present invention, it is possible to diagnose whether or not the high-voltage relay is welded by measuring the voltage applied to the resistance connected to the relay simply without receiving the inverter voltage as the CAN signal. When applied to a relay, it is possible to diagnose whether or not the quick-charge relay is fused in the vehicle.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Modified forms are also included within the scope of the present invention.

10: Battery 20: Power relay assembly (PRA)
21: first main relay 22: second main relay
23: precharge relay 24: precharge resistor
30: Motor controller (MCU) 31: Inverter
40: drive motor 50: controller (battery controller BMS)
51a, 51b: Rapid charging relay 52: Power supply circuit part
53: converter (ADC) 54: CPU
55: voltage detection circuit 56: analog signal output section

Claims (10)

A power supply circuit unit for applying a voltage for fault diagnosis;
A first resistor connected between both ends of the contact of the relay to be diagnosed and connected to the ground terminal;
A second resistor connected in series between the power supply circuit portion and the first resistor;
A converter for converting a voltage signal applied to both ends of the second resistor in a state where a voltage is applied through the second resistor from the power supply circuit to a digital signal form; And
A CPU for determining whether or not the relay is fused from a voltage signal in the form of a digital signal output from the converter;
And the relay fault diagnosis device of the vehicle.
The method according to claim 1,
Further comprising a circuit opening / closing switch provided on each circuit connecting between both ends of the first resistor and the respective contacts of the relay, and being turned on / off in accordance with a control signal of the CPU.
The method according to claim 1,
Wherein the relay to be diagnosed is a rapid charge relay of a vehicle for opening and closing a circuit between a DC link stage and a rapid charger between a battery and a motor controller.
The method according to claim 1,
Wherein the relay to be diagnosed is either one of a first main relay, a second main relay, and a pre-charge relay provided at a DC link end between the battery and the motor controller, or each relay. Device.
The method according to claim 1,
The CPU determines that the relay is in a fusion state when the voltage between both ends of the second resistor input from the conversion unit is different from the set normal voltage value due to the formation of the current path leading to the ground via the contact of the second resistor and the relay The relay fault diagnosis apparatus of the present invention.
The method of claim 5,
Wherein the normal voltage value is set to a voltage across the second resistor which is generated when a current path is formed through the first resistor and the second resistor to the ground terminal in a state where no relay fusion occurs, Diagnostic device.
A first resistor connected between the both ends of the contact of the relay to be diagnosed and connected to the ground terminal, a second resistor connected in series between the power supply circuit and the first resistor, a second resistor connected between both ends of the second resistor, And a CPU for receiving a voltage signal in the form of a digital signal output from the converting unit, the method comprising the steps of:
Applying a voltage for fault diagnosis from the power supply circuit unit through a second resistor;
Converting the voltage signal applied to both ends of the second resistor into a digital signal and outputting the digital signal; And
Determining whether the relay is fused from the voltage signal input from the conversion unit by the CPU;
Wherein the fault diagnosis method comprises the steps of:
The method of claim 7,
When the CPU receives the voltage across both ends of the second resistor from the converting unit, the circuit opening / closing switch provided on each circuit connecting between both ends of the first resistor and the respective contacts of the relay is turned off to open the circuit Of the vehicle.
The method of claim 7,
The CPU determines that the relay is in a fusion state when the voltage between both ends of the second resistor input from the conversion unit is different from the set normal voltage value due to the formation of the current path leading to the ground via the contact of the second resistor and the relay And the relay fault diagnosis method comprises the steps of:
The method of claim 9,
Wherein the steady voltage value is set to a voltage across the second resistor which is generated when a current path connecting the first resistor and the second resistor to the ground terminal is formed in a state where no relay fusion occurs, Diagnostic method.

Images