JP2003102101A - Power control device for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and quickly charge a condenser, to detect loose connection of relays, and to accurately and quickly detect connection defect in the relay. SOLUTION: A power control device 10 is equipped with a controller 12, a voltmeter 14 which detects the voltage value of a battery 56, a voltmeter 54 which detects voltage value of a condenser 62 connected in parallel with a load 58 and so on, a function which opens/closes a relay RY1 which directly connects an anode of the load 58 with the anode of the battery 56, a function which opens/closes a relay RY2 which directly connects the cathode of the battery 56 with and a cathode of the load 58, and a function which opens/closes a relay RY3 which is connected in parallel with the relay RY1 and connects the battery 56 with the load 58 via a resistor 60. Based on the voltage values of the battery 56 and of the condenser 62, determination of opening/closing or failure of the RY1, the RY2 and the RY3 is made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on an electric vehicle such as a pure electric vehicle or a hybrid electric vehicle and connects or disconnects a battery and a load. That said).

[0002]

2. Description of the Related Art FIG. 5 is a circuit diagram showing a conventional power supply control device. Hereinafter, description will be given with reference to this drawing.

A conventional power supply control device 50 comprises a controller 52 and a voltmeter 54, a battery 56 and a load 58.
And the function of opening and closing the relay RY1 that directly connects the positive side of the battery 56 and the load 58, and the function of opening and closing the relay RY2 that directly connects the negative side of the battery 56 and the load 58, and the function of connecting the battery 56 and the load 58 connected in parallel to the relay RY1. It has a function of opening and closing the relay RY3 connected through the resistor 60.
The voltmeter 54 includes a capacitor 6 connected in parallel with a load 58.
The voltage value of 2 is detected. Although not shown, the load 58 includes a drive motor, an inverter that supplies electric power to the drive motor, and the like. The capacitor 62 functions to keep the output voltage of the battery 56 constant against load fluctuations and noise. For example, the output voltage of the battery 56 is 240V, and the resistance value of the resistor 60 is 200Ω.

Next, the operation of the power supply controller 50 will be described.

If the relays RY1 and RY2 are suddenly closed at the time of starting, the contacts of the relays RY1 and RY2 may be welded due to the rush current into the capacitor 62. Therefore, an operation called "precharge" is executed. That is, the relays RY1, RY2, RY3 are first opened, and then the relays RY2, RY3 are closed to make the capacitor 62
Is gradually charged, and after the capacitor 62 is sufficiently charged, the relay RY3 is opened and at the same time the relay RY1 is closed. Here, whether or not the capacitor 62 is sufficiently charged is determined based on whether or not the voltage value of the capacitor 62 has reached a certain value or whether a certain time has elapsed.

Further, there is known one having the following function of detecting welding of the relays RY1, RY2 and RY3 (for example, Japanese Patent Laid-Open No. 2000-134707).

At the time of starting, first, the relays RY1, RY2, R
When the relay RY3 is closed from the open state of Y3 and the voltage of the capacitor 62 rises, it is determined that the relay RY2 is welded. Then, the relay RY2 is closed and the relay RY is closed.
3 is opened to cause the load 58 to consume power, and the capacitor 62
If the voltage does not decrease, it is determined that either the relay RY1 or the relay RY3 is welded.

[0008]

However, the conventional power supply control device 50 has the following problems.

[0009]. To judge that the capacitor 62 is sufficiently charged based only on the voltage value of the capacitor 62 is
Lack of accuracy. For example, even if the voltage value of the capacitor 62 reaches a certain value, if the voltage value of the battery 56 is higher than that, the relays RY1 and RY2 may be welded.

[0010]. If it is determined that the capacitor 62 is sufficiently charged based on the elapsed time, the time required for the determination is inevitably long. This is because it is necessary to set the certain period of time sufficiently long so that welding does not occur even when the charging time becomes long.

[0011]. The contact failure at the contacts of the relays RY1 and RY2 could not be detected. This is because even if the voltage value of the capacitor 62 drops, it cannot be distinguished whether it is due to the voltage value drop of the battery 56 or the voltage drop at the relays RY1, RY2. This contact failure causes the contact to have a high resistance due to oxidation or dust, and finally to welding or the like. The term "contact failure" as used herein includes the case where the relay contact does not operate normally due to a failure of the drive circuit of the relays RY1 and RY2 or a mechanical failure.

[0012]. Since the change over time of the voltage value of the capacitor 62 is used for the determination of the welding of the relays RY1, RY2, RY3, it takes more time for accurate detection.

.. Relays RY1 and RY when the vehicle starts
Since it takes a certain amount of time to judge the welding of 2 and RY3, there is a problem that rapid start cannot be performed. Also, if welding is found at startup,
Since it takes a considerable amount of time to procure and replace the parts,
The vehicle was virtually out of service.

[0014]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to firstly charge the capacitor 62 accurately and quickly, and secondly to relay RY.
The contact failure of 1 and RY2 can be detected. Thirdly, relay RY
An object of the present invention is to provide a power supply control device capable of accurately and promptly detecting the welding of 1 and RY2 and improving convenience.

[0015]

A power supply control apparatus according to the present invention has a function of opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a positive electrode of a battery and a load. Side, or the function of opening and closing a second relay that directly connects the other of the negative electrode side, and the function of opening and closing a third relay that is connected in parallel to the first relay and connects the battery and the load via a resistor, It is equipped with. The power supply control device includes a battery voltage detecting means for detecting a voltage value of a battery, a capacitor voltage detecting means for detecting a voltage value of a capacitor connected in parallel with a load, a battery voltage detecting means and a capacitor voltage detecting means. Control for inputting the voltage value of the battery and the voltage value of the capacitor and opening / closing the first to third relays or judging the failure of the first to third relays based on the voltage value of the battery and the voltage value of the capacitor And means (claim 1).

For example, the control means inputs the voltage value of the battery and the voltage value of the capacitor from the battery voltage detecting means and the capacitor voltage detecting means, and the second and the second from the state in which the first to third relays are open. The third relay is closed, and the first relay is closed and the third relay is opened when the difference between the voltage value of the battery and the voltage value of the capacitor is equal to or less than a certain value after a certain period of time. ).

For example, the control means inputs the voltage value of the battery and the voltage value of the capacitor from the battery voltage detection means and the capacitor voltage detection means, and the first and second relays are closed and the third relay is opened. In some cases, if the difference between the voltage value of the battery and the voltage value of the capacitor is a certain value or more, it is determined that the first and second relays have poor contact (claim 3).

For example, the control means inputs the voltage value of the battery and the voltage value of the capacitor from the battery voltage detecting means and the capacitor voltage detecting means, and the first and second relays are closed and the third relay is opened. In some cases, even if the difference between the voltage value of the battery and the voltage value of the capacitor is less than a certain value, if the voltage value of the capacitor is less than the certain value, it is determined that there is an abnormality in the first and second relays. (Claim 4). The "abnormalities of the first and second relays" here include abnormalities of high-voltage components such as fuses and battery cables.

For example, the power supply control device further has a function of causing the load to consume power. At this time, the control means inputs the voltage value of the battery and the voltage value of the capacitor from the battery voltage detection means and the capacitor voltage detection means, and the first and second relays are closed and the third relay is open. From opening the at least one of the first and second relays and causing the load to consume power,
If the difference between the voltage value of the battery and the voltage value of the capacitor is less than a certain value, it is determined that the opened relay is welded (Claim 5). Here, since "at least one of the first and second relays is opened", only the first relay is opened,
There are three ways: open the second relay only, open both the first and second relays.

At this time, the determination of welding may be executed when the vehicle is stopped (claim 6). Further, the stop time may be a time immediately before the vehicle is completely stopped after the vehicle is running or the battery is charged (claim 7). For example, when the high voltage system of the vehicle shifts from the activated state to the stopped state. In practice, it is a few seconds after turning the ignition switch on and off, or a few seconds after the charging is complete.

[0021]

1 is a circuit diagram showing an embodiment of a power supply control device according to the present invention. Hereinafter, description will be given with reference to this drawing. However, the same parts as those in FIG.

The power supply control device 10 of this embodiment includes a controller 12 as control means, a voltmeter 14 as battery voltage detection means for detecting the voltage value of a battery 56, and a voltage value of a capacitor 62 connected in parallel with a load 58. Voltmeter 54 as a capacitor voltage detecting means for detecting the battery 5 and the function of opening and closing the relay RY1 that directly connects the positive electrode side of the battery 56 and the load 58, and the battery 5
6 has a function of opening and closing a relay RY2 that directly connects the negative side of the load 58, a function of opening and closing a relay RY3 that is connected in parallel to the relay RY1 and that connects the battery 56 and the load 58 via a resistor 60, 58 has a function of consuming electric power.

Further, the controller 12 has the following functions (1) to (3).

[0024]. The voltage value v1 of the battery 56 and the voltage value v2 of the capacitor 62 are input from the voltmeter 14 and the voltmeter 54, and the relays RY1, RY2, RY3 are closed from the state in which the relays RY1, RY2, RY3 are open, and when a certain time has elapsed, The voltage value v1 of the battery 56 and the capacitor 62
When the difference between the voltage value v2 and the voltage value v2 is less than a certain value, the relay RY1 is closed and the relay RY3 is opened.

[0025]. When the voltage value v1 of the battery 56 and the voltage value v2 of the capacitor 62 are input from the voltmeter 14 and the voltmeter 54, and when the relays RY1 and RY2 are closed and the relay RY3 is open, the voltage value v1 of the battery 56.
If the difference between the voltage value v2 of the capacitor 62 and the voltage value v2 of the capacitor 62 is a certain value or more, it is determined that the relays RY1 and RY2 have a contact failure.

.. The voltage value v1 of the battery 56 and the voltage value v2 of the capacitor 62 are input from the voltmeter 14 and the voltmeter 54, and at least one of the relays RY1 and RY2 is opened from the state where the relays RY1 and RY2 are closed and the relay RY3 is open. And the load 58 consumes power, the voltage value v1 of the battery 56 and the capacitor 62
If the difference from the voltage value v2 is less than a certain value, it is determined that at least one of the opened relays RY1 and RY2 is welded.

The controller 12 is a microcomputer including, for example, a CPU, a ROM, a RAM, an input / output interface, etc., and many functions described above are realized by programs. The voltmeter 14 and the voltmeter 54 are composed of, for example, a voltage dividing resistor and an A / D converter.

FIG. 2 is a flow chart showing the operation at the time of starting the power supply control device 10. Hereinafter, description will be given with reference to FIGS. 1 and 2. The voltage value v1 of the battery 56 and the voltage value v2 of the capacitor 62 will be referred to as "battery voltage v
1 ”and“ capacitor voltage v2 ”. Further, turning on the relay means closing the relay, and turning off the relay means opening the relay.

First, when the driver turns on the ignition switch (starts traveling) or inserts the charging plug into the vehicle (starts battery charging), a vehicle power supply start request is generated (step 101). Then, it is confirmed that the battery voltage v1 is within the normal range, that is, is equal to or higher than the constant voltage Va (v1> Va) (step 102), and the relays RY2 and RY3 are turned on (step 103). On the other hand, if v1> Va is not established in step 102, the battery voltage v1 is abnormally low, so a fail signal indicating abnormal battery voltage is output (step 104).
The relays RY1, RY2 and RY3 are turned off to stop the activation (step 105).

Subsequently, if the capacitor voltage v2 is less than the constant voltage Vb even after the elapse of the constant time T1 (step 106), the capacitor 62 cannot be normally charged for some reason, and a fail signal indicating abnormal precharge is output. It is output (step 107) and the activation is stopped (step 105). On the other hand, when v2 <Vb is not satisfied in step 106, if the difference between the battery voltage v1 and the capacitor voltage v2 is equal to or more than the constant voltage Vc even after the elapse of the constant time T2 (step 108), the capacitor 6 is returned for some reason.
Since No. 2 cannot be charged normally, a fail signal of precharge abnormality is output (step 109) and the activation is stopped (step 105). Note that T1 <T2, for example, T1 is about 1 second and T2 is about 10 seconds.

Then, in step 108, the difference between the battery voltage v1 and the capacitor voltage v2 is the constant voltage Vc.
If it is less than (step 110), the capacitor 62 has been normally charged, so the relay RY1 is turned on and the relay R is turned on.
The Y3 is turned off and the activation is completed (step 111).
When the relay RY1 is turned on, the difference between the battery voltage v1 and the capacitor voltage v2 is very small.
1 does not weld. The constant voltage Vc is the relay RY
1 and RY2 are voltage differences at which welding does not occur, and are determined by the contact performance of the relays RY1 and RY2, the capacitance value of the capacitor 62, and the like.

When the battery voltage is v1, the capacitance value of the capacitor 62 is C, and the resistance value of the resistor 60 is R, the capacitor voltage v2 (t) after t seconds is given by the following equation. v2 = v1 [1-exp {-t / (CR)}] The capacitor voltage v2 (T1) after T1 seconds is t =
It is obtained by substituting T1 = 1. Constant voltage V
b is set to a value obtained by subtracting the margin from v2 (1).

FIG. 3 is a flowchart showing the operation of the power supply control device 10 during traveling or battery charging. Hereinafter, description will be given with reference to FIGS. 1 and 3.

First, the battery voltage v1 and the capacitor voltage v2 are compared, and if the difference between them is equal to or more than a constant voltage Vd (step 121), an abnormal voltage drop is recognized in the relays RY1 and RY2, so contact failure occurs. Of the fail signal (step 122) and the relays RY1 and RY2 are turned off (step 123). On the other hand, the battery voltage v
Even if the difference between 1 and the capacitor voltage v2 is less than the constant voltage Vd, if the capacitor voltage v2 is less than the constant voltage Ve (step 124), a low voltage fail signal is output (step 125), and the relay RY1, RY2 is turned off (step 123).

The reason why the relays RY1 and RY2 are turned off in step 123 is that the relays RY1 and RY2 may be welded because a large current flows when the contact is suddenly improved. Therefore, the constant voltage Vd is equal to the relay RY.
1 and RY2 are set to the voltage difference corresponding to the minimum current value for welding. The constant voltage Ve is set to a low value that is not normally detected.

FIG. 4 is a flow chart showing the operation of the power supply control device 10 when it is stopped. Hereinafter, description will be given with reference to FIGS. 1 and 4.

(1) When neither of the relays RY1 and RY2 is welded First, the driver turns off the ignition switch (ends traveling) or removes the charging plug from the vehicle (ends battery charging). As a result, a vehicle power supply stop request is generated (step 131). Then relay RY
1 is turned off (step 132), and power is consumed by the load 58 (step 133). Then, the battery voltage v
1 is compared with the capacitor voltage v2, and if the difference between them is equal to or greater than the constant voltage Vf, it is normal (step 13
4) minimize power consumption at load 58 (step 1
35), the relay RY3 is turned on and the relay RY2 is turned off (step 136). Then, the capacitor voltage v2
Is monitored, and if it does not rise, it is normal (Step 1
37), turn off relay RY3 (step 13)
8).

(2) Only the relay RY1 is welded If the difference between the battery voltage v1 and the capacitor voltage v2 is less than the constant voltage Vf in step 134, the relay R
Since Y1 is welded, a fail signal for relay RY1 welding is output (step 139), and relay RY2 is turned off (step 140).

(3) When only the relay RY2 is welded If the capacitor voltage v2 rises in step 137, the relay RY2 is welded. Therefore, the relay RY2 welding failure signal is output (step 141), and the relay RY2 is welded. RY3 is turned off (step 138).

(4) When both relays RY1 and RY2 are welded After turning off relay RY2 in step 140,
The battery voltage v1 and the capacitor voltage v2 are compared, and if the difference between them is less than the constant voltage Vf (step 14).
2), relay RY2 is also welded, so relay RY2
A welding failure signal is output (step 143).

Needless to say, the present invention is not limited to the above embodiment. For example, although the name of the present invention is “for an electric vehicle ...”, the present invention is not limited to an electric vehicle and can be suitably used for a system including a large-capacity power source and a load.

[0042]

According to the power supply control device of the present invention, the capacitor can be charged accurately and promptly by determining whether the relay is opened or closed or the failure based on the voltage values of the battery and the capacitor, and the contact failure of the relay can be prevented. It is possible to detect, and it is possible to accurately and quickly detect the welding of the relay.

According to the power supply control device of the second aspect, the first relay is closed and the third relay is closed when the difference between the voltage value of the battery and the voltage value of the capacitor is equal to or less than a certain value after a certain period of time. By opening, it is possible to accurately determine the completion time of the precharge, so that the welding of the relay can be prevented and the precharge can be completed in the minimum necessary time.

According to the power supply control device of the third aspect, the difference between the voltage value of the battery and the voltage value of the capacitor is constant when the first and second relays are closed and the third relay is open. If the value is equal to or more than the value, it is possible to accurately detect the contact failure of the relay by determining that the first and second relays have the contact failure, so that the welding of the relay can be prevented.

According to the fourth aspect of the power supply control device, the difference between the voltage value of the battery and the voltage value of the capacitor is constant when the first and second relays are closed and the third relay is open. Even if it is less than the value, if the voltage value of the capacitor is less than a certain value, it is judged that there is an abnormality in the first and second relays. Can be detected.

According to the fifth aspect of the power supply control device, at least one of the first and second relays is opened while the first and second relays are closed and the third relay is open. Even if the load consumes power, if the difference between the battery voltage value and the capacitor voltage value is less than a certain value, it is judged that the opened relay is welded, and Since the difference between the voltage value of the battery and the voltage value of the capacitor is used instead of the change, the welding of the relay can be detected accurately and quickly.

According to the power supply control device of the sixth or seventh aspect, by determining the welding when the vehicle is stopped,
Since it does not spend extra time at startup, it can start quickly. Moreover, since the welding is found at the time of stopping, the procurement and replacement of the component can be performed during the stopping, so that the vehicle cannot be used for a short time. Therefore, convenience can be improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a power supply control device according to the present invention.

FIG. 2 is a flowchart showing an operation at startup in the power supply control device of FIG.

3 is a flowchart showing an operation of the power supply control device of FIG. 1 during traveling or charging of a battery.

FIG. 4 is a flowchart showing the operation of the power supply control device of FIG. 1 when stopped.

FIG. 5 is a circuit diagram showing a conventional power supply control device.

[Explanation of symbols]

10 Power control device 12 Controller (control means) 14 Voltmeter (battery voltage detection means) 56 battery 58 load 62 capacitor 54 Voltmeter (capacitor voltage detection means) RY1 relay (first relay) RY2 relay (second relay) RY3 relay (third relay)

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02J 7/00 302 H02J 7/00 302C F term (reference) 5G003 AA04 BA01 CA11 CC02 DA07 FA04 FA06 GC05 5H115 PA08 PG04 PI16 PO02 PU01 PU21 PV09 SE06 SE10 TI05 TI09 TR19 TU03 TU06 TU12 TU20 UI35

Claims (7)

[Claims] 1. A function for opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a function of directly connecting the other of the positive electrode side and the negative electrode side of the battery and the load. A power supply control device for an electric vehicle having a function of opening and closing a second relay, and a function of opening and closing a third relay connected in parallel to the first relay and connecting the battery and the load via a resistor In, battery voltage detection means for detecting the voltage value of the battery, capacitor voltage detection means for detecting the voltage value of a capacitor connected in parallel to the load, the battery voltage detection means and the capacitor voltage detection means from the battery Input voltage value of the capacitor and the voltage value of the capacitor, and based on the voltage value of the battery and the voltage value of the capacitor, the first to third relay A power supply control device for an electric vehicle, comprising: a control unit that opens or closes or determines a failure of the first to third relays. 2. A function of opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a function of directly connecting the other of the positive electrode side and the negative electrode side of the battery and the load. A power supply control device for an electric vehicle having a function of opening and closing a second relay, and a function of opening and closing a third relay connected in parallel to the first relay and connecting the battery and the load via a resistor In, battery voltage detection means for detecting the voltage value of the battery, capacitor voltage detection means for detecting the voltage value of a capacitor connected in parallel to the load, the battery voltage detection means and the capacitor voltage detection means from the battery And the voltage value of the capacitor are input, and the second and third relays are closed from the state in which the first to third relays are open. Then
A control means for closing the first relay and opening the third relay when the difference between the voltage value of the battery and the voltage value of the capacitor is equal to or less than a certain value after a lapse of a certain time. A power supply control device for an electric vehicle characterized by the above. 3. A function of opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a function of directly connecting the other positive electrode side or negative electrode side of the battery and the load. A power supply control device for an electric vehicle having a function of opening and closing a second relay, and a function of opening and closing a third relay connected in parallel to the first relay and connecting the battery and the load via a resistor In, battery voltage detection means for detecting the voltage value of the battery, capacitor voltage detection means for detecting the voltage value of a capacitor connected in parallel to the load, the battery voltage detection means and the capacitor voltage detection means from the battery Input voltage value of the capacitor and the voltage value of the capacitor, and when the first and second relays are closed and the third relay is open, An electric vehicle, comprising: a control unit that determines that the first and second relays have a contact failure if the difference between the battery voltage value and the capacitor voltage value is a certain value or more. Power control device. 4. A function of opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a function of directly connecting the other positive electrode side or negative electrode side of the battery and the load. A power supply control device for an electric vehicle having a function of opening and closing a second relay, and a function of opening and closing a third relay connected in parallel to the first relay and connecting the battery and the load via a resistor In, battery voltage detection means for detecting the voltage value of the battery, capacitor voltage detection means for detecting the voltage value of a capacitor connected in parallel to the load, the battery voltage detection means and the capacitor voltage detection means from the battery Input voltage value of the capacitor and the voltage value of the capacitor, and when the first and second relays are closed and the third relay is open, Even if the difference between the battery voltage value and the voltage value of the capacitor is less than a certain value, if the voltage value of the capacitor is less than the certain value, it is determined that the first and second relays are abnormal. A means for controlling electric power supply for an electric vehicle, comprising: 5. A function of opening and closing a first relay that directly connects one of a positive electrode side and a negative electrode side of a battery and a load, and a function of directly connecting the other of the positive electrode side and the negative electrode side of the battery and the load. A function of opening and closing a second relay, a function of opening and closing a third relay connected in parallel to the first relay and connecting the battery and the load via a resistor, and a function of causing the load to consume power. In a power supply control device for an electric vehicle comprising: a battery voltage detection unit that detects a voltage value of the battery; a capacitor voltage detection unit that detects a voltage value of a capacitor connected in parallel to the load; and the battery voltage detection unit. Means and the capacitor voltage detecting means, the voltage value of the battery and the voltage value of the capacitor are input, and the first and second relays are closed and the first and second relays are closed. Even if at least one of the first and second relays is opened from the state where the third relay is open and the load consumes power, the difference between the voltage value of the battery and the voltage value of the capacitor is A power supply control device for an electric vehicle, comprising: a control unit that determines that the opened relay is welded if the value is a predetermined value or less. 6. The electric vehicle power source control device according to claim 5, wherein the determination of welding is performed when the vehicle is stopped. 7. The electric vehicle power source control device according to claim 6, wherein the stop time is a time immediately before the vehicle is completely stopped after the vehicle is running or the battery is charged.