WO2013150825A1

WO2013150825A1 - Power supply and anomaly detection method of power supply

Info

Publication number: WO2013150825A1
Application number: PCT/JP2013/054353
Authority: WO
Inventors: 俊介天貝
Original assignee: 日産自動車株式会社
Priority date: 2012-04-03
Filing date: 2013-02-21
Publication date: 2013-10-10

Abstract

This power supply is provided with: a smoothing capacitor (13) electrically connected to the terminals of the battery (11); a precharge switch (16) provided between the battery and the smoothing capacitor and connected in series with a precharge resistance (17); a control means (10) which, by controlling ON/OFF operations of the precharge switch, controls the charging current which precharges the smoothing capacitor; a current detection means (19) for detecting the charging current; a storage means (10) which, when the precharge switch is set to ON during normal operation, stores the charging current during normal operation at the time at which a prescribed first amount of time has elapsed since the precharge switch was turned ON; and an anomaly detection means (10) which detects the occurrence of anomalies by calculating the difference between the charging current detected by the current detection means at the time at which the aforementioned first amount of time had elapsed since the precharge switch was set to ON, and the charging current during normal operation at the time at which the first amount of time has elapsed, and by comparing said difference and a prescribed first threshold value.

Description

Power supply device and abnormality detection method for power supply device

The present invention relates to a power supply device and an abnormality detection method for the power supply device.
This application claims priority based on Japanese Patent Application No. 2012-84595 filed on Apr. 3, 2012. For designated countries that are allowed to be incorporated by reference, The contents described in the application are incorporated into the present application by reference and made a part of the description of the present application.

Conventionally, a smoothing capacitor has been provided between the input terminals of the inverter of an electric vehicle. First, the precharge relay is closed and the charging current is limited by a precharge resistor connected in series with the precharge relay while precharging the smoothing capacitor. In addition, a technique for preventing damage to the contact of the main relay by determining that the precharge is completed when the charging current becomes equal to or less than a predetermined reference value after a predetermined time has elapsed and closing the main relay is known. (For example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-304501

However, in the above prior art, for example, when the resistance value of the precharge resistor is increased due to an abnormality in the precharge resistor, it is erroneously assumed that the precharge is terminated even though the precharge is insufficient. There is a problem of judging. Alternatively, there is a possibility that a secondary abnormality such as a charging current continues to flow despite the occurrence of a circuit abnormality and the precharge resistor is blown out.

The problem to be solved by the present invention is to provide a power supply apparatus and an abnormality detection method for a power supply apparatus that can appropriately detect the abnormality when an abnormality occurs.

The present invention provides a difference between a charging current actually flowing and a normal charging current measured in advance when a predetermined time elapses after the precharging switch for precharging the smoothing capacitor is turned on. The above problem is solved by detecting occurrence of abnormality by comparing the calculated difference with a predetermined threshold.

According to the present invention, it is possible to determine whether or not an abnormality has occurred based on the difference between the charging current that is actually flowing and the charging current at the normal time measured in advance. It can be detected early.

FIG. 1 is a block diagram showing a power supply device according to this embodiment. FIG. 2 is a diagram showing the transition of the current value at the normal time when the smoothing capacitor 13 is charged at the normal time. FIG. 3 is a diagram showing the transition of the current value when an abnormality has occurred in the smoothing capacitor 13. FIG. 4 is a diagram showing the transition of the current value when a circuit short circuit abnormality occurs and when a circuit disconnection abnormality occurs. FIG. 5 is a diagram illustrating the transition of the current value when abnormality occurs in the precharge resistor 17 and the downstream device. FIG. 6 is a diagram for explaining a method of setting the second time t2.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a power supply device 100 according to this embodiment.
The power supply device 100 according to the present embodiment is a power supply device mounted on, for example, a hybrid vehicle or an electric vehicle, and includes a battery 11 formed by connecting a plurality of cells in series as shown in FIG. A load 12 is connected to both ends of the battery 11 via a first main relay 14 and a second main relay 15 in the junction box 20 and a switch 18. The cell constituting the battery 11 is, for example, a lithium ion secondary battery, and the battery 11 is provided with a current sensor 19 for detecting a current input to and output from the battery 11. Although it does not specifically limit as the load 12, An inverter etc. are mentioned.

In addition to the first main relay 14 and the second main relay 15, the junction box 20 includes a precharge relay 16 and a precharge resistor 17 connected in parallel to the first main relay 14.

The power supply device 100 according to the present embodiment includes a smoothing capacitor 13 connected in parallel with the load 12. The smoothing capacitor 13 is connected to the second main relay 15 and the precharge relay 16 when the system is activated. The battery is charged by being closed. Note that the precharge relay 16 is connected in series with the precharge resistor 17, so that when the smoothing capacitor 13 is charged, the precharge resistor 17 is charged while limiting the current. Become.

The control device 10 controls the opening and closing of the first main relay 14, the second main relay 15, and the precharge relay 16 provided in the junction box 20 and the opening and closing of the switch 18 connected to the load 12. Thus, the power supply device 100 is controlled. Further, the control device 10 manages the current input to and output from the battery 11 by acquiring information on the current detected by the current sensor 19.

Next, the control when charging the smoothing capacitor 13 when the system of the power supply apparatus 100 is started will be specifically described. The control described below is executed by the control device 10.

As described above, when the smoothing capacitor 13 is charged in the power supply device 100 of the present embodiment, the second main relay 15 and the precharge relay 16 are closed, and the current is limited by the precharge resistor 17, Charging is performed.

FIG. 2 is a graph showing the transition of the current value when the smoothing capacitor 13 is charged in the power supply device 100 of the present embodiment. FIG. 2 shows the transition of the current value when the power supply device 100 of the present embodiment is normal, that is, the transition of the current value when no abnormality has occurred. As shown in FIG. 2, when the second main relay 15 and the precharge relay 16 are closed at time t0, first, the current corresponding to the voltage of the battery 11 and the resistance value of the precharge resistor 17, that is, the battery 11 When the voltage is E _bat and the resistance value of the precharge resistor 17 is R, a current of E _bat / R flows, and then the charging current gradually attenuates as the smoothing capacitor 13 is charged. .

On the other hand, for example, when the smoothing capacitor 13 is abnormal, specifically, when an abnormality occurs in which the electric charge accumulated in the smoothing capacitor 13 is discharged to the electric load, as shown in FIG. The value will change. That is, when the smoothing capacitor 13 is abnormal, the current decay rate with respect to the elapsed time from the start of the charging of the smoothing capacitor 13 is slow compared to the normal current value transition. Will behave differently.

Or, for example, when a circuit short circuit abnormality occurs or when a circuit disconnection abnormality occurs, as shown in FIG. 4, the current value remains unchanged at E _bat / R when a circuit short circuit abnormality occurs. When the circuit disconnection is abnormal, the current value remains zero and does not change. That is, even when a circuit short-circuit abnormality or a circuit disconnection abnormality occurs, a behavior different from the transition of the current value at normal time is exhibited.

For this reason, in the present embodiment, the transition of the normal current value as shown in FIG. 2, that is, the transition of the normal current value when the smoothing capacitor 13 is charged in the normal state is normal. What is stored in advance as hourly current value transition data and detects an abnormality occurring in the power supply device 100 by comparing the stored normal current value transition data with the actually detected current value It is. The normal current value transition data is obtained by, for example, charging the smoothing capacitor 13 under normal conditions, measuring the relationship between the elapsed time when charging and the current value in advance, and obtaining the obtained measurement results. Can be obtained on the basis.

A specific method for detecting an abnormality is as follows. That is, first, when the second main relay 15 and the precharge relay 16 are closed and the time after the elapse of a predetermined time since the charging of the smoothing capacitor 13 is set to the first time t1, as shown in FIG. to, from the normal time current value transition data, to obtain a first current value I ₁ corresponding to the first time t1. When the second main relay 15 and the precharge relay 16 are closed and the smoothing capacitor 13 is charged, the actual time detected by the current sensor 19 at the time when the first time t1 has elapsed from the time t0. The current value I _obs is acquired. Next, the difference ΔI _obs−1 = | I _obs −I ₁ | between the actual current value I _{obs at} the first time t ₁ and the first current value I ₁ at normal time is calculated, and the calculated difference ΔI _{obs− It} is determined whether 1 is greater than a predetermined first threshold value α1. As a result of the determination, if the difference ΔI _obs−1 is larger than the first threshold α1, that is, if ΔI _obs−1 > α1, it is determined that an abnormality occurs. The first threshold value α1 is not particularly limited. For example, the first threshold value α1 is set to a value that can be determined to be clearly deviated from the current transition at the normal time.

For example, the case where the abnormality of the smoothing capacitor 13 shown in FIG. 3 occurs will be described as an example. When the smoothing capacitor 13 is charged, when the first time t1 has elapsed from the time t0, the current sensor 19 The actually detected current value I _obs is I _obs = I _a . Then, a difference ΔI _a-1 = | I _a −I ₁ | between the actually detected current value I _a and the first current value I ₁ at normal time is calculated, and the calculated difference ΔI _a−1 The first threshold value α1 is compared. As a result, current I _a in the first hour t1, as is apparent from FIG. 3, because clearly deviate from the current transition of normal, [Delta] I _a-1> [alpha] 1, and the reason that, in this case Therefore, it is determined that an abnormality has occurred.

If it is determined that an abnormality has occurred in this way, a process for canceling the precharge is executed. Specifically, charging the smoothing capacitor 13 is stopped by opening the second main relay 15 and the precharge relay 16. In this case, a process of notifying the user that an abnormality has occurred may be executed.

Similarly, when the circuit short-circuit abnormality shown in FIG. 4 or the circuit disconnection abnormality occurs, when the smoothing capacitor 13 is charged, the time t0 to the first time t1 are obtained. The current values actually detected by the current sensor 19 at the time when only elapses are I _b and I _c , respectively. Then, a difference ΔI _b-1 = | I _b −I ₁ |, ΔI _c−1 = | I _c −I ₁ | between the current values I _b and I _c and the first current value I _{1 in} the normal state The calculated differences ΔI _b-1 and ΔI _c-1 are compared with the first threshold value α1. Since the current values I _b and I _{c at} the first time t1 are clearly deviated from the normal current transition, as is apparent from FIG. 4, ΔI _a-1 > α1, and in this case It is determined that an abnormality has occurred. In this case as well, the process for stopping the precharge is executed in the same manner as described above.

However, on the other hand, for example, when the precharge resistor 17 is abnormal, specifically, the resistance value of the precharge resistor 17 or a device located downstream of the junction box 20, specifically, a motor, an inverter, or a heater When the resistance value of the DC / DC converter or the like is abnormal, the current value changes as shown in FIG. That is, compared with the transition of the current value at the normal time, when the precharge resistor 17 and the downstream device are abnormal, the initial current value itself when starting the charging of the smoothing capacitor 13 shows a low value, but the elapsed time Therefore, the current decay rate is slow, so that the behavior of the current value is different from that of the normal state, while the current value is substantially equal in the vicinity of the first time t1.

Therefore, when such an abnormality occurs, the abnormality may not be detected only by comparing the current values at the first time t1.

On the other hand, in the present embodiment, even when it is determined that there is no abnormality as a result of performing the abnormality determination at the first time t1, as shown in FIG. 5, the predetermined time after the first time t1 has elapsed. In the second time t2 (second time t2> second time t1), the current values are compared in the same manner as described above, and abnormality is determined based on the comparison result.

Specifically, first, as shown in FIG. 2, from the normal state current value transition data, and acquires the second current value I ₂ corresponding to the second time t2. Then, after it is determined that there is no abnormality at the first time t1, the actual current value I _obs detected by the current sensor 19 is acquired at the time when the second time t2 has elapsed from the time t0. Then, a difference ΔI _obs−2 = | I _obs −I ₂ | between the actual current value I _{obs at} the second time t2 and the second current value I ₂ at normal time is calculated, and the calculated difference ΔI _{obs− It} is determined whether 2 is larger than a predetermined second threshold value α2. As a result, when the difference ΔI _obs−2 is larger than the second threshold α2, that is, when ΔI _obs−2 > α2, it is determined that an abnormality has occurred. The second threshold value α2 is not particularly limited. For example, the second threshold value α2 may be set to a value that can be determined to be clearly deviated from the normal current transition, and may be the same value as the first threshold value α1 described above. Alternatively, it may be a value different from the first threshold value α.

For example, when the precharge resistor 17 shown in FIG. 5 and a downstream device abnormality occur are described as an example, when the smoothing capacitor 13 is charged, the first time t1 has elapsed from the time t0. Even if no abnormality is detected as a result of the abnormality determination, the abnormality determination is performed again at the time when the second time t2 has elapsed from the time t0. Specifically, the current value I _obs actually detected by the current sensor 19 at the second time t2 is I _obs = I _d , and the actually detected current value I _d and the normal second value The difference ΔI _d−2 = | I _d −I ₂ | from the current value I ₂ is calculated, and the calculated difference ΔI _d−2 is compared with the second threshold value α2. Further, as clearly shown in FIG. 5, the current value I _{d at} the second time t2 is clearly deviated from the current transition at the normal time, and therefore ΔI _d−2 > α2, and in this case, It is determined that an abnormality has occurred. In this case as well, the process for stopping the precharge is executed as described above.

In this embodiment, if no abnormality is detected at the first time t1 and the second time t2, the current value detected by the current sensor 19 after the elapse of the second time t2 is a predetermined value. When the current is equal to or less than the threshold current I _Fin , it is determined that the charging of the smoothing capacitor 13 has been completed, and the first main relay 14 is closed so that power can be supplied from the battery 11 to the load 12 It is said.

As described above, according to the present embodiment, at the first time t1, the current value I _obs detected by the current sensor 19 is compared with the first current value I ₁ calculated in the normal state, and the difference ΔI therebetween. _{When obs−1} = | I _obs −I ₁ | is larger than the first threshold value α1, it is determined that an abnormality has occurred. Therefore, according to the present embodiment, when an abnormality occurs, the abnormality can be detected at a relatively early stage.

In addition, according to the present embodiment, even if it is determined that there is no abnormality at the first time t1, the current value I detected by the current sensor 19 again at the second time t2 after that. _Obs is compared with the second current value I ₂ calculated in the normal state, and when the difference ΔI _obs−2 = | I _obs −I ₂ | is larger than the second threshold value α2, an abnormality occurs. It is determined that Therefore, according to the present embodiment, depending on the type of abnormality that has occurred, even if it is determined that there is no abnormality once in the first time t1 due to the influence of the current transition, again in the second time t2, By making an abnormality determination, it is possible to prevent erroneous detection. In addition, by performing abnormality detection twice in the first time t1 and the second time t2, it is possible to specify the abnormal part / abnormal mode. That is, for example, when it is determined that there is no abnormality at the first time t1, and when it is determined that there is an abnormality at the second time t2 after that, the precharge resistor 17 shown in FIG. It can be determined that the abnormality is, specifically, the resistance increase abnormality of the precharge resistor 17 and the resistance increase abnormality of the downstream device.

In the present embodiment, when the abnormality is determined as a result of the abnormality determination at the first time t1 and the second time t2, the precharge relay 16 is opened to stop charging the smoothing capacitor 13 when the abnormality is determined. As a result, it is possible to effectively prevent the occurrence of malfunctions (for example, malfunctions such as fusing of various resistors) due to continued charging of the smoothing capacitor 13 in a state where an abnormality has occurred.

Further, in the present embodiment, it is determined that no abnormality is detected at the first time t1 and the second time t2, and the charging of the smoothing capacitor 13 is finished after the second time t2. The first main relay 14 is closed. That is, in the present embodiment, after confirming that no abnormality has occurred, the first main relay 14 is closed. Thus, according to the present embodiment, the first main relay 14 Contact damage can be prevented appropriately.

In the above example, when an abnormality occurs in the smoothing capacitor 13 as shown in FIGS. 3 to 5, when a circuit short circuit abnormality occurs, when a circuit disconnection abnormality occurs, Exemplifies a case where an abnormality occurs in the precharge resistor 17 and the downstream device. However, according to the present embodiment, it is possible to detect an abnormality other than these abnormal portions and abnormal modes.

The first time t1 described above is not particularly limited. For example, when the voltage of the battery 11 is E _bat and the resistance value of the precharge resistor 17 is R, the E _bat / R It is preferable to calculate the fusing time of the precharge resistor 17 when the current continues to flow, and to set the first time t1 to be shorter than the fusing time of the precharge resistor 17. A first time t1, by setting a shorter time than fusing time of the precharge resistor 17, for example, like an open circuit short circuit abnormality shown in FIG. 4, the precharge resistor 17, a current of E _{bat / R} In the case of an abnormal mode that continues to flow, since the abnormality can be detected in a time shorter than the fusing time of the precharge resistor 17 (that is, the first time t1), secondary such as fusing of the precharge resistor 17 can be detected. Failure can be prevented appropriately.

Further, the second time t2 described above is not particularly limited. For example, a first current range D1 (I ₁ −α1 ≦ D1 ≦ I ₁ + α1) determined not to be abnormal at the first time t1, It is preferable that the second current range D2 (I ₂ −α2 ≦ D2 ≦ I ₂ + α2) determined not to be abnormal at time t2 is set so as not to overlap. That is, it is preferable that I ₁ −α1 that is the lower limit value of the first current range D1 and I ₂ + α2 that is the upper limit value of the second current range D2 are set so as to have a relationship represented by the following formula.
Δ = (I ₁ −α1) − (I ₂ + α2)> 0
By setting the second time t2 to such a time, for example, the current sensor 19 can appropriately detect even in an abnormal mode in which the detected current is constant. That is, for example, even if the value of the current detected by the current sensor 19 is a value within the first current range D1 that is determined not to be abnormal at the first time t1, and is constant, the second Since the second current range D2 determined not to be abnormal at the time t2 is a range different from the first current range D1, it is possible to appropriately detect such an abnormality.

In the above-described embodiment, the smoothing capacitor 13 is the smoothing capacitor of the present invention, the precharge relay 16 is the precharge switch of the present invention, and the first main relay 14 and the second main relay 15 are the present. The current sensor 19 corresponds to the current switch of the present invention, and the control device 10 corresponds to the control means, storage means, and abnormality detection means of the present invention.

As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Power supply device 10 ... Control apparatus 11 ... Battery 12 ... Load 13 ... Smoothing capacitor 14 ... 1st main relay 15 ... 2nd main relay 16 ... Precharge relay 17 ... Precharge resistance

Claims

A smoothing capacitor electrically connected to both electrodes of the battery;
A precharge switch provided between the battery and the smoothing capacitor and connected in series with a precharge resistor;
Control means for controlling a charging current to precharge the smoothing capacitor by controlling on / off operation of the precharging switch;
Current detecting means for detecting a charging current;
Storage means for storing a normal charging current when a predetermined first time has elapsed since the precharge switch was turned on when the precharge switch was turned on in a normal state;
The difference between the charging current detected by the current detection means when the first time has elapsed since the precharge switch was turned on and the normal charging current when the first time has elapsed is calculated. A power supply apparatus comprising: an abnormality detection unit that detects the occurrence of an abnormality by comparing the difference with a predetermined first threshold value.
The power supply device according to claim 1,
The abnormality detection unit is configured such that a difference between a charging current detected by the current detection unit when the first time has elapsed and a normal charging current when the first time has elapsed is greater than the first threshold. A power supply device that determines that an abnormality has occurred.
The power supply device according to claim 2,
The storage means is normal when a predetermined second time longer than the first time elapses after the precharge switch is turned on when the precharge switch is turned on. I memorize the charging current at the time,
The abnormality detecting means is configured such that a difference between a charging current detected by the current detecting means when the first time has elapsed and a normal charging current when the first time has elapsed is equal to or less than the first threshold value. When the second time has elapsed since the precharge switch was turned on, the charging current detected by the current detection means and the normal charging current when the second time has elapsed And determining that an abnormality has occurred when the difference is greater than a predetermined second threshold value.
The power supply device according to any one of claims 1 to 3,
The control unit turns off the precharge switch when an abnormality is detected by the abnormality detection unit.
The power supply device according to any one of claims 1 to 4,
The first time is set to a time shorter than the time when the precharge resistor is blown when the charging current when the precharge switch is turned on continues to flow through the precharge resistor. A featured power supply.
The power supply device according to claim 5,
At the time of the lapse of the first time, the value of the charging current during normal and I 1, the first threshold value and [alpha] 1, at the time has elapsed the second time, the value of the charging current during normal and I 2, When the second threshold value is α2, the second time is set so as to satisfy the following formula (1).
(I 1 -α1)-(I 2 + α2)> 0 (1)
The power supply device according to any one of claims 3 to 6,
A main switch connected in parallel with the precharge switch;
The control unit turns on the main switch when the charging current detected by the current detection unit becomes a predetermined value or less after the second time has elapsed.
The charging current actually flowing at the time when a predetermined time has passed since the precharge switch for precharging the smoothing capacitor electrically connected to both electrodes of the battery is turned on, and the normal time measured in advance An abnormality detection method for a power supply device that detects the occurrence of an abnormality by calculating a difference between the charging current and a predetermined threshold value.