KR102601985B1 - Device for fault detection of pra - Google Patents

Abstract

The present invention relates to a PRA fault diagnosis device. Specifically, it relates to a device that measures the input and output voltages of the main relay and precharge relay of the PRA and diagnoses faults in the main relay and precharge relay according to the voltage value standard at each point. .
The PRA fault diagnosis device according to the present invention includes a first main relay, one side of which is connected in series to the (+) terminal of the battery and the other side of which is connected in series with the (+) terminal of the load; A precharge relay connected in parallel with the first main relay; a second main relay, one side of which is connected in series to the (-) terminal of the battery and the other side of which is connected in series with the (-) terminal of the load; One side of the first main relay is point A, one side of the precharge relay is point B, the other side of the first main relay is point C, one side of the second main relay is point D, and the other side of the second main relay is a measuring unit that sets to point E and measures voltages at points A to E; a determination unit that determines a failure by comparing the voltages at the points A to E measured by the measurement unit with a preset reference value; and a control unit that controls ON/OFF of the first main relay, the precharge relay, and the second main relay according to the failure determined by the determination unit. Includes.

Description

ＰＲＡ fault diagnosis device {DEVICE FOR FAULT DETECTION OF PRA}

The present invention relates to a PRA fault diagnosis device. Specifically, it relates to a device that measures the input and output voltages of the main relay and precharge relay of the PRA and diagnoses faults in the main relay and precharge relay according to the voltage value standard at each point. .

A hybrid vehicle (HEV: Hybrid Electric Vehicle) refers to a future vehicle that can reduce exhaust gases and improve fuel efficiency by adopting not only an engine but also a motor drive source as an auxiliary power source.

Hybrid vehicles ultimately have the main purpose of realizing a highly efficient vehicle by increasing fuel efficiency and creating an eco-friendly vehicle by improving exhaust performance.

Power transmission in a hybrid vehicle may be achieved by having an engine, a motor, and an automatic transmission directly connected on one axis, and a clutch is arranged between the engine and the motor.

And, as a configuration for these operations, a hybrid battery, that is, a high-voltage battery, is connected to the motor through an inverter so that it can be charged and discharged.

The power relay assembly (PRA), which includes relays and resistors, is used as a device located between the high-voltage battery and the motor and responsible for the connection.

These PRAs use mechanical relays to supply and cut off power to the load, and the contact parts of these mechanical relays may fuse together during use, causing high voltage to flow in the circuit.

Additionally, the contact portion of the mechanical relay may not operate in an open state, making it impossible to supply power to the load.

Therefore, a device that can diagnose the failure of each relay of the PRA is required in order to normally supply and block power to the motor.

Korean Patent No. 10-1521985 Korean Patent Publication No. 10-2010-0040819

Accordingly, the purpose of the present invention is to provide a PRA fault diagnosis device that can diagnose failures in the main relay and precharge relay according to the voltage value standard at each point by measuring the input and output voltages of the main relay and precharge relay of the PRA. there is.

The PRA fault diagnosis device according to the present invention includes a first main relay, one side of which is connected in series to the (+) terminal of the battery and the other side of which is connected in series with the (+) terminal of the load; A precharge relay connected in parallel with the first main relay; a second main relay, one side of which is connected in series to the (-) terminal of the battery and the other side of which is connected in series with the (-) terminal of the load; One side of the first main relay is point A, one side of the precharge relay is point B, the other side of the first main relay is point C, one side of the second main relay is point D, and the other side of the second main relay is a measuring unit that sets to point E and measures voltages at points A to E; a determination unit that determines a failure by comparing the voltages at the points A to E measured by the measurement unit with a preset reference value; and a control unit that controls ON/OFF of the first main relay, the precharge relay, and the second main relay according to the failure determined by the determination unit. Includes.

In the present invention, the measuring unit is each provided with a measuring circuit for measuring the voltage of the points A to E, and the measuring circuit has a terminal that receives the voltage of the points A to E to be pulled up with a first voltage. ) is configured so that when the voltages at the points A to E are floating, the first voltage is measured.

In the present invention, the determination unit, in a state in which the first and second main relays and the precharge relay are all OFF, the voltages measured through the measurement unit are the voltages at the points A and B, respectively, and the second voltage is the second voltage. If the first condition that the voltages at points C and E are the first voltage and the voltage at the point D is the third voltage is satisfied, it is determined to be normal, the precharge relay is turned on through the control unit, and the first condition is determined. is not satisfied, and if the voltages at the points A and C satisfy the second condition, which is the second voltage, the first main relay or the precharge relay is determined to be contact fused, and the second condition is determined. In the unsatisfied state, if the voltages at points D and E satisfy the third condition, which is the third voltage, the second main relay is judged as contact fusion, and if the third condition is not satisfied, it is determined as a circuit defect. judge.

In the present invention, the determination unit determines that, when the precharge relay is ON and the first and second main relays are OFF, the voltage measured through the measurement unit is the voltage at the points A, B, and C, respectively. 2 voltage, the voltage at point D is the third voltage, and the voltage at point E is the first voltage. If it satisfies the fourth condition, it is judged to be normal and the first main relay is turned on through the control unit, In a state in which the fourth condition is not satisfied, if the fifth condition that the voltage at point C is the second voltage is satisfied, the first main relay is judged as a contact open, and the fifth condition is not satisfied. If the sixth condition is satisfied that the voltage at point C is the third voltage, it is determined that the (-) terminal of the load is defective.

In the present invention, the determination unit determines that when the precharge relay and the first main relay are ON and the second main relay is OFF, the voltage measured through the measurement unit is the voltage at the points A, B, and C. If the seventh condition, which is the second voltage and the voltages at points D and E are respectively the third voltage, is determined to be normal, the second main relay is turned on through the control unit, and the seventh condition is satisfied. In this state, if the voltage at point C satisfies the eighth condition that is less than 80% of the voltage at point A, the load is determined to be in a charging state, and if the eighth condition is not satisfied, the seventh condition is applied. Recheck that you are satisfied.

According to the present invention, the hybrid PRA control method diagnoses a failure of the main relay through a current sensor to prevent additional failures that may occur by the electronic switch, and controls the electronic switch according to the current value to prevent damage to the electronic switch. It prevents possible overload and controls overheating, allowing the application of lower capacity electronic switches and eliminating the application of additional heat dissipation components.

1 is a schematic configuration diagram of a PRA failure diagnosis device according to an embodiment of the present invention.
Figure 2 is an exemplary diagram of a measurement circuit of a measurement unit according to an embodiment of the present invention.
Figure 3 is a flowchart showing the PRA failure diagnosis process according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Additionally, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted.

1 is a schematic configuration diagram of a PRA failure diagnosis device according to an embodiment of the present invention.

Referring to FIG. 1, the PRA failure diagnosis device according to an embodiment of the present invention can be divided into the PRA unit 110 shown in (a) of FIG. 1 and the failure diagnosis unit 120 shown in (b) of FIG. 1. .

First, referring to (a) of FIG. 1, the PRA unit 110 of the PRA failure diagnosis device 100 includes a first main relay 111 for switching power between the battery 10 and the load 20, and a first main relay 111 for switching power between the battery 10 and the load 20. When turning on the 2nd main relay 113 and the first main relay 111, it includes a precharge relay 112 that prevents damage due to a sudden flow of current (inrush current), and a precharge relay 111. It is configured to include a precharge resistor 30 to limit the current flowing in.

The first main relay 111 is connected in series between the (+) terminal of the battery 10 and the (+) terminal of the load 20, and the precharge resistor 30 and the precharge relay 112 are connected in series. It is composed of and connected in parallel with the first main relay 111.

The second main relay 113 is connected in series between the (-) terminal of the battery 10 and the (-) terminal of the load 20.

In one embodiment of the present invention, the battery 10 is a high-voltage battery that outputs a direct current voltage of hundreds of V, and accordingly, the first and second main relays 111 and 113 are also high-voltage relays for high-voltage switching. It consists of

At this time, the point where the voltage is measured to diagnose the failure is indicated in (a) of FIG. 1.

Point A is the midpoint between the (+) terminal of the battery 10 and the first main relay 111, and is a point for measuring the voltage of the (+) terminal of the battery 10.

Point B is a point on one side of the precharge relay 112 and is the midpoint between the precharge resistor 30 and the precharge relay 112.

Point C is a point on the other side of the first main relay 111 and is the midpoint between the first main relay 111 and the (+) terminal of the load 20.

Point D is the midpoint between the (-) terminal of the battery 10 and the second main relay 113, and is a point for measuring the voltage of the (-) terminal of the battery 10.

Point E is a point on the other side of the second main relay 113 and is the midpoint between the second main relay 113 and the (-) terminal of the load 20.

In this way, when the voltage measurement point for failure diagnosis of the PRA unit 110 is set, the failure diagnosis unit 120 measures the voltage at each point and compares it with a preset reference voltage to diagnose the failure and control the relay.

Referring to (b) of FIG. 1, the failure diagnosis unit 120 of the PRA failure diagnosis device 100 includes a measurement unit 121 that measures the voltage at points A to E, and points A to E measured by the measurement unit 121. A determination unit 122 for determining failure of the precharge relay 112 and the first and second main relays 111 and 113 by comparing the voltage of E with a preset reference value, whether or not the failure is determined by the determination unit 122 It consists of a control unit 123 that controls the precharge relay 112 and the first and second main relays 111 and 113.

The measuring unit 121 is provided with separate measuring circuits for measuring the voltages of points A to E, and each measuring circuit is provided with terminals that receive the voltages of points A to E, and points A to E are floating ( Since the voltage value cannot be measured in the floating state, to prevent errors in this case, the terminal that receives the voltage of the measurement circuit is configured as a pull-up with the first voltage so that points A to E are floating. It is desirable to configure the first voltage to be measured when it is in a floating state.

As a means for measuring the voltage, the measurement unit 121 can use various known voltage measurement means, and is not limited to any one measurement means.

An example of the measurement circuit of this measurement unit 121 is shown in FIG. 2.

Figure 2 is an exemplary diagram of a measurement circuit of a measurement unit according to an embodiment of the present invention.

Referring to FIG. 2, the measurement circuit of the measurement unit 121 shows an example of measuring the voltage at point A, and is composed of a photocoupler 124 and resistors R1, R2, and R3.

The photocoupler 124 receives the “ON” control signal as an input and inputs the voltage at point A to the A/D converter.

At this time, the “ON” control signal may be output from the control unit 123. Instead of always measuring the voltage value at point A, when the “ON” control signal is output from the control unit 123 at a necessary time, the voltage value can be measured. It is configured to do this.

When the photocoupler 124 operates by the “ON” control signal, the voltage at point A is divided by resistors R1 and R2, and the voltage value applied to resistor R2 is input to the A/D converter and measured.

The voltage distribution according to these resistors R1 and R2 is because the voltage at points A to E can have a level of hundreds of volts due to the high voltage battery 10, and is configured to convert it to a voltage level that can be measured by the A/D converter. am.

In addition, the reason why the converted voltage at point A is pulled up to the first voltage by resistor R3 before being input to the A/D converter is because, as mentioned above, when the voltage at point A is in a floating state, the voltage value cannot be measured. The reason is to determine floating by measuring the first voltage value, which is a constant voltage.

The measurement circuit of the measurement unit 121 having this configuration is applied not only to point A but also to points B to E, respectively.

When the measurement circuit of the measurement unit 121 shown in FIG. 2 is applied, examples of voltages that can be measured at points A to E are shown in Table 1 below.

Enter points A to E measure voltage note Floating first voltage First voltage≠second voltage and
1st voltage ≠ 3rd voltage Battery (+) voltage second voltage Battery (+) voltage × (R2/(R1 + R2)) Battery (-) voltage Third voltage 0V

That is, when the voltage at points A to E is floating, the measured voltage becomes the first voltage by pull-up using resistor R3, and the voltage at points A to E is the voltage of the (+) terminal of the battery 10. In this case, the measured voltage is the voltage value divided by the battery (+) voltage by resistors R1 and R2, and this is called the second voltage.

In addition, when the voltage at points A to E is the voltage of the (-) terminal of the battery 10, the measured voltage is measured based on the battery (-) terminal potential, so there is no potential change, so 0V is measured and this is measured. It is called 3 voltage.

That is, when the state of the battery 10 is normal, the types of voltage values that can be measured at points A to E are the first voltage, the second voltage, and the third voltage, and the precharge relay 111 and the first voltage are And, depending on the ON/OFF status of the second main relays 111 and 113, the reference voltage values to be measured at points A to E may be set to any one of the first to third voltages, respectively.

Table 2 below shows the reference voltage values to be measured at points A to E according to the ON/OFF status of the precharge relay 111 and the first and second main relays 111 and 113.

condition Branch A Branch B point C Branch D point E ALL OFF second voltage second voltage first voltage Third voltage first voltage Precharge relay ON
2nd main relay OFF
1st main relay OFF second voltage second voltage second voltage Third voltage first voltage Precharge relay ON
2nd main relay ON
1st main relay OFF second voltage second voltage second voltage Third voltage Third voltage Precharge Millay ON
2nd main relay ON
1st main relay ON second voltage second voltage second voltage Third voltage Third voltage

Conditions were set according to the relay operation sequence of the PRA unit 110. When the PRA unit operates, the precharge relay 112 is turned on first, then the second main relay 113, which supplies negative power to the battery 10, is turned on, and finally the first main relay 111 is turned on. In order to supply power from the battery 10 to the load 20, conditions were sequentially set according to this sequence.

First, point A always measures the voltage at the (+) terminal of the battery 10 regardless of whether the relay is ON or OFF, so the second voltage becomes the reference voltage.

Point B, like point A, is also a point where the voltage of the (+) terminal of the battery 10 is measured through only one precharge resistor 30, so the reference voltage is the second voltage under all conditions, the same as point A.

Point C is a point where power is not supplied when all relays are OFF, so it is in a floating state and the first voltage is measured. However, under the condition that the precharge relay is ON, the (+) of the battery 10 is applied regardless of the operation of other relays. ) terminal voltage is applied, so the second voltage is measured.

Since the voltage of the (-) terminal of the battery 10 is always applied to point D regardless of whether the relay is ON or OFF, the third voltage becomes the reference voltage.

Lastly, point E is a point where no power is supplied when the second main relay 113 is OFF, so it is in a floating state and the first voltage is measured, but under the condition that the second main relay 113 is ON, the other relay Since the voltage is applied to the (-) terminal of the battery 10 regardless of the operation, the third voltage is measured.

According to the reference voltage according to each relay operation condition, the determination unit 122 compares the voltages at points A to E measured by the measurement unit 121 to determine the failure of each relay.

The process of diagnosing a failure of the PRA by the determination unit 122 is shown in detail in FIG. 3.

Figure 3 is a flowchart showing the PRA failure diagnosis process according to an embodiment of the present invention.

First, in a state in which the first and second main relays 111 and 113 of the determination unit 122 and the precharge relay 112 are all OFF, the voltages at points A and B measured through the measurement unit 121 are respectively A first condition confirmation step (S101) is performed to check whether the voltage at point C and E is the first voltage, and the voltage at point D is the third voltage.

If the first condition is satisfied, the determination unit 122 determines that the PRA unit 110 with all relays OFF is normal, and turns on the precharge relay 112 through the control unit 123 to perform the precharge. Perform it (S105).

If the first condition is not satisfied, the determination unit 122 performs a second condition confirmation step (S107) to check whether the voltages at point A and point C are the second voltages, respectively.

If the voltages at point A and point C are the same as the second voltage, the contact point of either the precharge relay 112 or the first main relay 111 operates and the battery (+) voltage at point A is increased to point A. It means supplied to C.

This second condition is satisfied when all relays are turned off because fusion occurs at the contact point of either the precharge relay 112 or the first main relay 111 and is not controlled from the ON state to OFF. Therefore, the determination unit 122 determines that contact fusion has occurred in the precharge relay 112 or the first main relay 111 (S109).

When such a defect occurs, the user can stop the diagnosis and take steps to closely inspect the status of the precharge relay 112 or the first main relay 111, or replace both relays with normal relays.

If the second condition is not satisfied, the determination unit 122 performs a third condition confirmation step (S111) to check whether the voltages at point D and point E are the same as the third voltage.

If the voltages at point D and point E are the same as the third voltage as in the third condition, this means that the contact point of the second main relay 113 operates and the battery (-) voltage at point D is supplied to point E. .

Therefore, if the third condition is satisfied, the determination unit determines that contact fusion has occurred in the second main relay 113 (S113) and allows the user to replace it with a normal relay.

If the third condition is not satisfied, it is determined that the circuit is defective and all parts of the PRA unit 110 are replaced or it is checked whether any parts other than the circuit parts are defective.

After step S105, the determination unit 112 diagnoses a defect in the PRA unit 110 when the precharge relay 112 is turned on.

The determination unit 113 performs a fourth condition confirmation step (S117) to check whether the voltages at points A, B, and C satisfy the second voltage, point D satisfies the third voltage, and point E satisfies the first voltage. do.

If the fourth condition is satisfied, the PRA unit 110 with the precharge relay 112 turned on is judged to be normal, and the second main relay 113 is turned on through the control unit 123 to turn on the battery 10. Ensure that the (-) voltage is supplied to the (-) terminal of the load (20) (S119).

If the fourth condition is not satisfied, the determination unit 122 performs a fifth condition confirmation step (S121) to check whether the voltage at point C satisfies the first voltage.

If the precharge relay 112 is normally turned on, the second voltage, which is the battery (+) voltage, should be measured at point C. If the voltage at point C is measured as the first voltage, point C is in a floating state, which means that the precharge This means that the contact point of the relay 112 did not operate.

Therefore, if the fifth condition is satisfied, the determination unit 122 determines that the precharge relay 112 has a contact open defect (S123).

If the fifth condition is not satisfied, the determination unit 122 performs a sixth condition confirmation step (S125) to check whether the voltage at point C satisfies the third voltage.

If the sixth condition is satisfied, point C connected to the (+) terminal of the load 20 is not the second voltage, which is the (+) voltage of the battery 10, but the third voltage, which is the (-) voltage of the battery 10. Since this means the measured value, the determination unit 122 determines that the (-) terminal and the (+) terminal of the load 20 are shorted (S127).

After step S119, the determination unit 112 diagnoses a defect in the PRA unit 110 when the precharge relay 112 and the second main relay 113 are turned on.

The determination unit 113 performs the seventh condition confirmation step (S129) to check whether the voltages at points A, B, and C satisfy the second voltage and the voltages at points D and E satisfy the third voltage.

If the 7th condition is satisfied, both the precharge relay 112 and the second main relay 113 are determined to be normally ON, and the first main relay 111 is turned ON through the control unit 123. Ensure that the battery (+) voltage is supplied to the (+) terminal of the load (20) (S131).

However, if the 7th condition is not satisfied, the 8th condition confirmation step (S133) is performed to check whether the voltage at point C is less than 80% of the voltage at point A.

In this step, when the (+) voltage of the battery 10 is supplied to the (+) terminal of the load 20 by the precharge relay 112, it is connected to the capacitor (not shown) included in the circuit of the load 20. This is a step to determine a situation in which a voltage lower than the (+) voltage of the battery 10 is detected at the (+) terminal of the load 20 because the voltage is not sufficiently charged.

If the 8th condition is satisfied, the capacitor of the load 20 is not sufficiently charged, so the determination unit 122 determines that the load 20 is in a charged state and performs again from step S129, which is the 7th condition confirmation step. (S135) to confirm that the load 20 is sufficiently charged and to end the diagnosis.

Through this process, defects in the parts that make up the PRA can be diagnosed in detail, and the relays can be turned on sequentially without any failure of each part, thereby increasing the stability of the PRA operation process.

Although the present invention described above has been explained in detail through preferred embodiments, it should be noted that the present invention is not limited to the contents of these embodiments. Those of ordinary skill in the art to which the present invention pertains will recognize that, although not shown in the examples, various imitations or improvements to the present invention can be made within the scope of the appended claims, all of which fall within the technical scope of the present invention. Belonging is self-evident. Accordingly, the true scope of technical protection of the present invention should be determined by the technical spirit of the attached patent claims.

100: PRA failure diagnosis device 110: PRA unit
111: first main relay 112: precharge relay
123: Second main relay 120: Failure diagnosis unit
121: measurement unit 122: judgment unit
123: Control unit 10: Battery
20: load 30: precharge resistance

Claims (5)

a first main relay whose one side is connected in series to the (+) terminal of the battery and the other side is connected in series to the (+) terminal of the load;
a precharge relay connected in parallel with the first main relay;
a second main relay, one side of which is connected in series to the (-) terminal of the battery and the other side of which is connected in series with the (-) terminal of the load;
One side of the first main relay is point A, one side of the precharge relay is point B, the other side of the first main relay is point C, one side of the second main relay is point D, and the other side of the second main relay is a measuring unit that sets to point E and measures voltages at points A to E;
a determination unit that determines a failure by comparing the voltages at the points A to E measured by the measurement unit with a preset reference value; and
A control unit that controls ON/OFF of the first main relay, the precharge relay, and the second main relay according to the failure determined by the determination unit,
The measuring unit,
Each is provided with a measurement circuit for measuring the voltage of the points A to E, and the measurement circuit configures a pull-up with a first voltage at a terminal that receives the voltage of the points A to E, so that the point A When the voltages from E to E are floating, the first voltage is measured,
The judgment department,
When both the first and second main relays and the precharge relay are OFF, the voltages measured through the measuring unit are the voltages at points A and B, respectively, and the voltages at points C and E are the second voltages. If the first condition, which is the first voltage and the voltage at point D is the third voltage, is satisfied, it is judged to be normal and the precharge relay is turned on through the control unit, and in a state where the first condition is not satisfied, If the voltages at the points A and C respectively satisfy the second condition of the second voltage, the first main relay or the precharge relay is determined to be contact fused, and when the second condition is not satisfied, the point If the voltages of D and E satisfy the third condition, which is the third voltage, the second main relay is judged to be a contact fusion, and if the third condition is not satisfied, the PRA fault diagnosis device is judged to be a circuit defect. delete delete A first main relay whose one side is connected in series to the (+) terminal of the battery and the other side is connected in series to the (+) terminal of the load;
A precharge relay connected in parallel with the first main relay;
a second main relay, one side of which is connected in series to the (-) terminal of the battery and the other side of which is connected in series with the (-) terminal of the load;
One side of the first main relay is point A, one side of the precharge relay is point B, the other side of the first main relay is point C, one side of the second main relay is point D, and the other side of the second main relay is a measuring unit that sets to point E and measures voltages at points A to E;
a determination unit that determines a failure by comparing the voltages at the points A to E measured by the measurement unit with a preset reference value; and
A control unit that controls ON/OFF of the first main relay, the precharge relay, and the second main relay according to the failure determined by the determination unit,
The measuring unit,
Each is provided with a measurement circuit for measuring the voltage of the points A to E, and the measurement circuit configures a pull-up with a first voltage at a terminal that receives the voltage of the points A to E, so that the point A When the voltages from E to E are floating, the first voltage is measured,
The judgment department,
In a state where the precharge relay is ON and the first and second main relays are OFF, the voltages measured through the measuring unit are the voltages at the points A, B, and C, respectively, and the voltages at the point D are the second voltages, respectively. If the voltage is the third voltage and the fourth condition that the voltage at point E is the first voltage is satisfied, it is judged to be normal and the second main relay is turned on through the control unit, but the fourth condition is not satisfied. In this case, if the voltage at point C satisfies the fifth condition of being the second voltage, the first main relay is determined to be a contact open, and in a state where the fifth condition is not satisfied, the voltage at point C is the second voltage. A PRA fault diagnosis device that determines that the (-) terminal of the load is defective when the 6th condition of 3 voltages is satisfied. A first main relay whose one side is connected in series to the (+) terminal of the battery and the other side is connected in series to the (+) terminal of the load;
A precharge relay connected in parallel with the first main relay;
a second main relay, one side of which is connected in series to the (-) terminal of the battery and the other side of which is connected in series with the (-) terminal of the load;
One side of the first main relay is point A, one side of the precharge relay is point B, the other side of the first main relay is point C, one side of the second main relay is point D, and the other side of the second main relay is a measuring unit that sets to point E and measures voltages at points A to E;
a determination unit that determines a failure by comparing the voltages at the points A to E measured by the measurement unit with a preset reference value; and
A control unit that controls ON/OFF of the first main relay, the precharge relay, and the second main relay according to the failure determined by the determination unit,
The measuring unit,
Each is provided with a measurement circuit for measuring the voltage of the points A to E, and the measurement circuit configures a pull-up with a first voltage at a terminal that receives the voltage of the points A to E, so that the point A When the voltages from E to E are floating, the first voltage is measured,
The judgment department,
When the precharge relay and the first main relay are turned on and the second main relay is turned off, the voltage measured through the measuring unit is the voltage at the points A, B, and C, respectively, and the second voltage is the second voltage. If the voltages at points D and E satisfy the seventh condition, which is the third voltage, it is judged to be normal and the first main relay is turned on through the control unit. In a state where the seventh condition is not satisfied, the point C If the voltage satisfies the eighth condition of being less than 80% of the voltage at point A, the PRA fault diagnosis device determines that the load is in a charged state and rechecks whether the seventh condition is satisfied.

Images