JP2002281602A - Voltage-computing method of power supply for electric vehicle, and power supply unit for the electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage correction method and a voltage correction device, capable of determining output voltage during a stable period of a high rate battery, immediately after keeping a main relay in a conducting status. SOLUTION: After a charging relay 6 is kept in a conducting status, a main relay 5 is kept in a conducting status, when the charging voltage of a capacitor C1 for stabilizing voltage has reached a prescribed level Von. A period Ton is measured, from the time when the charging relay 6 is kept in a conducting status until the time when the main relay 5 is kept in the conducting status. A charging voltage Vr of the capacitor C1 measured, immediately after the main relay 5, is kept in the conducing status (e.g., after the elapse of 100 ms) and voltage Vs is estimated, when the high rate battery 2 is stabilized, based on the voltage Vr and the period Ton. It is thus possible to determine voltage Vs in the stable period of the high rate battery 2 immediately, after the main relay 5 has been kept in the conducting status.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage calculation method for a power supply device mounted on an electric vehicle and a power supply device for an electric vehicle.

[0002]

2. Description of the Related Art Generally, electric vehicles (including hybrid vehicles) are equipped with a strong electric battery in order to supply electric power for rotating a driving motor. Then, the DC voltage output from the high-power battery is supplied to an inverter circuit via a voltage stabilizing capacitor,
The inverter circuit converts a DC voltage into a three-phase AC voltage, and supplies the three-phase AC voltage to the motor to rotate the motor.

In such a power supply device for an electric vehicle,
When the voltage output from the high-power battery is directly applied to the capacitor for voltage stabilization at the time of startup, an excessive rush current flows through the capacitor, which may place a large load on the circuit. Therefore, in order to prevent this, for example, Japanese Unexamined Patent Publication No.
As described in Japanese Patent Publication No. 217408, when a charging relay in which resistors are connected in series is installed in parallel with a main relay, and power is supplied from a high-power battery,
First, the charging relay is turned on to charge the capacitor for voltage stabilization to a certain level, and then after a while, the main relay is turned on to prevent the occurrence of inrush current. Have been.

[0004]

However, in such a conventional power supply device, when the charging relay is turned on, the high-current battery is discharged to charge the capacitor, so that the main relay is turned on. Even after the state is set, the voltage of the high-power battery is not stabilized for a while.
Therefore, in order to accurately measure the output voltage of the high-power battery, it is necessary to wait until the voltage of the high-power battery is stabilized.

On the other hand, after the main relay is turned on, it is desired to move the vehicle as soon as possible. In order to perform various controls, it is necessary to measure the output voltage of the high-power battery immediately and accurately. is there. However, since the output voltage of the high-power battery is not stable immediately after the main relay is turned on as described above, if this voltage value is used as it is, the capacity display calculated using this voltage and the determination of idle stop are performed. , The accuracy of sensor diagnosis and the like may be reduced.

In order to solve this problem, the charging voltage of the capacitor when the main relay was turned off last time is stored, and at the next start-up, the stored voltage value is used as it is, and the capacity display, idle Although various control methods such as determination of a stop and sensor diagnosis can be considered, in a hybrid vehicle, a load such as engine power generation is applied until the main relay becomes non-conductive, and the battery voltage is accurately determined. Is often not possible. Therefore, if the voltage at the time when the main relay was turned off last time is used as a calculation voltage value such as a capacity display at the time when the main relay is turned on next time, accuracy will be reduced.

As described above, the conventional electric vehicle power supply has a problem that it takes a long time until the output voltage of the main relay is stabilized after the main relay is turned on. A method of storing a voltage value when the relay is turned off and using the voltage value cannot obtain a highly accurate voltage value.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. It is an object of the present invention to accurately output the output voltage value of a high-power battery immediately after a main relay is turned on. An object of the present invention is to provide a method of calculating a voltage of a power supply for an electric vehicle and a power supply device for an electric vehicle that can be obtained.

[0009]

In order to achieve the above object, an invention according to claim 1 of the present application comprises a charging relay having a resistor connected in series, and a main relay connected in parallel with the charging relay and the resistor. At the time of startup, after the charging relay is turned on, the main relay is turned on to prevent an inrush current generated when a voltage is supplied from a high-power battery to a capacitor for voltage stabilization. A voltage calculating method for calculating the output voltage of the high-power battery of the electric vehicle power supply, wherein the charging voltage of the voltage stabilizing capacitor reaches a predetermined level after the charging relay is turned on. The charging relay is turned off and the main relay is turned on, the charging relay is turned on, and the main relay is turned on. After measuring the time Ton and turning on the main relay, the charging voltage Vr of the capacitor after a lapse of a predetermined time is measured. Based on the measurement time Ton and the charging voltage Vr, It is characterized by calculating the output voltage.

The invention according to claim 2 is characterized in that the output voltage Vc of the high-power battery is obtained by the following equation.

Vc = Vr + f (Ton) where f (Ton) is a voltage value uniquely set by the time Ton.

According to a third aspect of the present invention, the charging voltage Vi of the capacitor for voltage stabilization is measured immediately before the charging relay is turned on, and the measured voltage is added to the measuring time Ton and the charging voltage Vr. And calculating an output voltage of the high-power battery based on the charging voltage Vi.

The invention according to claim 4 is characterized in that the output voltage Vc of the high-power battery is obtained by the following two equations.

Vc = Vr + f (T) T = Ton + g (Vi) where g (Vi) is a time uniquely set by the charging voltage Vi, and f (T) is a voltage uniquely set by the time T. value.

According to a fifth aspect of the present invention, there is provided a high-power battery, comprising: a high-power battery; and a capacitor for stabilizing an output voltage of the high-power battery. An electric vehicle power supply device for correcting an output voltage to obtain an output voltage at a stable time, comprising: a main relay interposed between the high-power battery and the capacitor; Connected to a series connection circuit of a charging relay and a resistor, voltage detecting means for measuring the charging voltage of the capacitor, and at startup, after the charging relay is turned on, the charging voltage of the capacitor is set to a predetermined value. After reaching
The main relay is turned on, and a time Ton from when the charging relay is turned on to when the main relay is turned on is measured. A controller for measuring a charging voltage Vr and calculating an output voltage of the high-power battery based on the measuring time Ton and the charging voltage Vr is provided.

The invention according to a sixth aspect is characterized in that the controller obtains the output voltage Vc of the high-power battery by the following equation.

Vc = Vr + f (Ton) where f (Ton) is a voltage value uniquely set by the time Ton.

According to a seventh aspect of the present invention, the voltage detecting means measures the charging voltage Vi of the capacitor immediately before the charging relay is turned on, and the controller measures the measuring time Ton and the charging time Vi. The output voltage of the high-power battery is calculated based on the charging voltage Vi in addition to the voltage Vr.

The invention according to claim 8 is characterized in that the controller obtains the output voltage Vc of the high-power battery by the following two equations.

Vc = Vr + f (T) T = Ton + g (Vi) where g (Vi) is a time uniquely set by the charging voltage Vi and f (T) is a voltage uniquely set by the time T value.

[0021]

According to the first aspect of the present invention, after the charging relay is turned on, the time Ton until the voltage stabilizing capacitor reaches a predetermined level (time until the main relay is turned on) Ton is determined. Further, a charging voltage Vr after a predetermined time (for example, 100 ms) has elapsed after the main relay is turned on is determined, and the output voltage of the high-power battery is calculated based on the charging voltage Vr and the time Ton. .
Accordingly, it is possible to correct the amount of voltage drop of the high-power battery caused by the charging relay being in the conductive state, and it is possible to immediately obtain the voltage value when the high-power battery is stable.
Further, since the output voltage of the high-power battery is obtained by a time function, it is possible to obtain a voltage value including a voltage drop due to temperature and deterioration. As a result, various controls using accurate voltage values can be performed immediately after the main relay is turned on.

According to the second aspect of the present invention, since the correction for the voltage Vr is calculated by using the function f (Ton) set in advance, it is possible to calculate the voltage value with high accuracy.

According to the third aspect of the present invention, since the correction voltage for the voltage Vr is obtained by using the initial charging voltage Vi of the capacitor for stabilizing the voltage, a highly accurate calculation of the voltage value according to the state of charge of the high-power battery. Becomes possible.

According to the fourth aspect of the present invention, the time Ton is corrected using the function g (Vi) set in advance, so that a highly accurate voltage value can be calculated.

According to a fifth aspect of the present invention, after the charging relay is turned on under the control of the controller, the time until the voltage stabilizing capacitor reaches a predetermined level (the time until the main relay is turned on) ) Find Ton, and
A predetermined time (for example,
The charging voltage Vr after elapse of 100 ms) is obtained, and the output voltage of the high-power battery is calculated based on the charging voltage Vr and the time Ton. Therefore, it is possible to obtain a voltage value in which the amount of voltage drop of the high-power battery caused by setting the charging relay to the conducting state is corrected, and it is possible to immediately obtain the voltage value when the high-power battery is stable. Further, since the output voltage of the high-power battery is obtained by a time function, it is possible to obtain a voltage value including a voltage drop due to temperature and deterioration. As a result, immediately after the main relay is turned on,
Various types of control using accurate voltage values can be performed.

According to the sixth aspect of the present invention, the correction for the voltage Vr is calculated using the function f (Ton) set in advance, so that a highly accurate voltage value can be obtained.

According to the seventh aspect of the present invention, the correction voltage for the voltage Vr is obtained using the initial charging voltage Vi of the capacitor for stabilizing the voltage, so that a highly accurate voltage value corresponding to the state of charge of the high-power battery is obtained. Becomes possible.

According to the present invention, the time Ton is corrected by using the function g (Vi) set in advance, so that a highly accurate voltage value can be obtained.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a power supply device for an electric vehicle according to an embodiment of the present invention.
As shown in FIG. 1, the power supply device 1 includes a high-power battery 2 that supplies a driving voltage to a motor M1 for traveling, and a power head 3 that converts a DC voltage output from the high-power battery 2 into an AC voltage. And a DC-DC converter 8 that converts the output voltage of the high-power battery 2 to a DC voltage of, for example, 12 volts to generate a charging voltage for the sub-battery, and stabilizes the DC voltage output from the high-power battery 2 And a voltage sensor (voltage detecting means) 4 for measuring a charging voltage of the capacitor C1.

A main relay 5 installed on the output side of the high-power battery 2 for switching between conduction and non-conduction of the voltage output from the high-power battery 2, and a charging relay connected in parallel to the main relay 5 And a negative relay 7 that operates in conjunction with the main relay 5 and the charging relay 6. Furthermore,
The power supply device 1 includes a controller 9 serving as a control center.

In FIG. 1, connection lines indicated by thick lines indicate high-voltage lines, and connection lines indicated by thin lines indicate signal lines.

FIG. 2 is a flowchart showing a processing procedure by the controller 9, and FIG. 3 is a timing chart showing a change in the charging voltage of the capacitor C1. Hereinafter, the present embodiment will be described with reference to the flowchart and the timing chart. The operation of will be described.

When the ignition key is turned on, first, reading of the charging voltage of the capacitor C1 detected by the voltage sensor 4 is started (step ST1). Thereafter, the voltage value detected by the voltage sensor 4 is stored and stored as a voltage Vi (step ST2), and the charging relay 6 and the minus relay 7 are turned on (step ST2).
3).

At this time, since the DC voltage output from the high-power battery 2 is applied to the capacitor C1 via the charging relay 6 and the resistor R1, the rush current flowing into the capacitor C1 can be suppressed.

Next, a timer (not shown) mounted in the controller 9 is operated (step ST4). The charging voltage of the capacitor C1 rises with the passage of time, and when the charging voltage reaches a predetermined value Von (YES in step ST5), the timer is stopped, and the count value of the timer at this time is reduced. Time Ton is set (step ST6). This time Ton has a different value depending on the magnitude of the voltage initially charged in the capacitor C1.

This will be described below with reference to the timing chart shown in FIG. The characteristic curve S1 shown in FIG.
Is the initial charging voltage Vi (Vi-1) of the capacitor C1.
Shows the change of the charging voltage with the passage of time when is small (substantially zero volts), and the characteristic curve S2 shows the change of the charging voltage with the passage of time when the initial charging voltage Vi of the capacitor C1 is large (Vi = Vi−2). Is shown. Characteristic curve S1
As shown in the figure, when the initial charging voltage is small, the time Ton until reaching the predetermined value Von becomes long, and conversely,
As shown by the characteristic curve S2, when the initial charging voltage is large, the time Ton until reaching the predetermined value Von becomes short. Hereinafter, Ton in the characteristic curve S1 is represented by Ton-1 and Ton in the characteristic curve S2 is represented by Ton-2.

Thereafter, the main relay 5 is turned on,
At the same time, charging relay 6 is turned off (step ST
7). At this time, the conduction state of the minus relay 7 is continued.

Here, when the initial charging voltage is small, as shown by the characteristic curve S1, the charging voltage of the capacitor C1 changes to the time t2-1 when the charging voltage reaches the predetermined value Von.
(The time at which the main relay 5 is turned on), the voltage further rises and reaches a stable voltage Vs after a while. Similarly, when the initial charging voltage is a large characteristic curve S2, the charging voltage of the capacitor C1 is
From time t2-2 (the time when the main relay 5 is turned on) at which the charging voltage reaches the predetermined value Von, the charging voltage further increases,
After a while, the voltage reaches a stable voltage Vs.

In this embodiment, the main relay 5
Of the capacitor C1 at a point in time when a predetermined time elapses after this is turned on (this time is referred to as t3-1 and t3-2).
The charging voltage Vr (Vr-1, Vr-2) is measured (step ST8). The above-mentioned predetermined time (the time between t2-1 and t3-1 and the time between t2-2 and t3-2) is estimated from the control response time of the main relay 5 to the start of the vehicle load operation. The time is preferably set to 1 hour in the present embodiment.
00 ms.

The controller 9 calculates the time Ton (Ton-1, Ton-2), the initial charging voltage Vi (Vi-1, Vi-2), and the charging voltage V of the capacitor C1.
Based on r (Vr-1, Vr-2), the voltage value Vs when the output voltage of the high-power battery 2 is stabilized is predicted, and the predicted voltage Vc is obtained. That is, as shown in FIG. 3, the charging voltage of the capacitor C1 gradually increases after the lapse of the time Ton (Ton-1, Ton-2) and stabilizes when the voltage Vs is reached. −1, t3−2) and a voltage ΔV (ΔV−1, ΔV−2) that is a difference between the charging voltage Vr (Vr−1, Vr−2) and the predicted voltage Vc, and obtains the difference voltage Δ
V (ΔV-1, ΔV-2) is changed to the charging voltage Vr (Vr-1, Vr-
The predicted voltage Vc is obtained by adding to (2).

In the present embodiment, a function f (T) statistically obtained is set in advance as the difference voltage ΔV, and the function f (T) is set.
Using (T), the charging voltage V is calculated by the following equation (1).
c is obtained (step ST9).

Vc = Vr + f (T) (1) As shown in FIG. 4, as the time T (in this case, the time Ton) increases, the function f (T) becomes f (T) (= Δ
The value of V) changes so as to gradually increase.

Therefore, as shown by the characteristic curve S1 in FIG. 3, the initial charging voltage Vi (= Vi−
When 1) is small, the time Ton-1 from when the charging relay 6 is turned on to when the main relay 5 is turned on.
Is large, f (T) becomes large. On the other hand, as shown by the characteristic curve S2, the initial charging voltage Vi of the capacitor C1
When (Vi-2) is large, the time Ton-2 is small, so that f (T) is small. As a result, the predicted voltage Vc can be accurately obtained regardless of the magnitude of the initial charging voltage Vi.

Then, a process of calculating the battery control initial value is performed based on the predicted voltage Vc obtained by the above equation (1) (step ST10). Hereinafter, the calculation of the battery control initial value will be described.

Stable voltage Vs (= Vc) of high-power battery 2
Is obtained, an SOC (State Of Charge; a numerical value indicating a state of charge when the full charge is set to 100) of the high-power battery 2 is uniquely obtained based on the stable voltage Vs (open-circuit voltage). An initial value of the input / output available power can be obtained based on the SOC.

That is, the characteristic curve S3 shown in FIG. 5 is a characteristic diagram showing the relationship between the open circuit voltage (OCV) and the SOC.
As shown in the figure, the SOC is uniquely determined with respect to the open-circuit voltage, and when the open-circuit voltage increases, the SOC changes so as to increase. FIG. 6 shows the dischargeable power with respect to the SOC (characteristic curve S4) and the chargeable power (characteristic curve S4).
5 is a characteristic diagram showing 5), and as shown in the figure, dischargeable power and chargeable power are uniquely determined with respect to SOC.

That is, when the stable voltage Vs is obtained, the dischargeable power and the chargeable power (the initial value of the inputtable power) of the high-power battery 2 can be obtained based on the stable voltage Vs. Then, based on the initial value, the current output power value can be obtained from the IV characteristics.

Then, according to the obtained power value, DC-
The vehicle control such as the DC converter 8, the power head 3, and the engine being turned on is started (step ST11). In this way, a stable output voltage Vs (= Vc) of the high-power battery 2 is obtained in a short time after the ignition is turned on,
Various controls can be performed based on the voltage Vs.

As described above, in the power supply device 1 according to the present embodiment, the charging relay 6 is turned on when the voltage output from the high-power battery 2 is started, and then the main relay 5 is turned on. Rush current flowing into the device can be prevented.

After the charging relay 6 is turned on,
The time Ton from when the charged voltage of the capacitor C1 reaches the voltage Von of the predetermined level to when the main relay 5 is turned on is measured, and based on the time Ton, the difference voltage f (T) (= Δ
V). Then, by adding this difference voltage f (T) to the charging voltage Vr of the capacitor C1 at the time t3, the voltage Vs at the time of stability is predicted. Therefore, the output voltage when the high-power battery 2 is stable can be accurately obtained in a very short time of about 100 ms after the charging relay 6 is turned on, and the capacity display, idle stop determination, sensor diagnosis, and the like can be performed with high accuracy. Will be able to do it.

Since the voltage value is calculated by the time function,
It is possible to obtain a voltage value including a voltage drop due to temperature and deterioration. Further, when the ignition is restarted immediately after the ignition is turned off, the capacitor C
Even if the discharge of No. 1 is not completed, it is not affected.

In the above embodiment, the case where the state of charge of the high-power battery 2 is good has been described. For example, when the high-power battery 2 is left unused for a long time, the high-power battery 2 Of the battery may deteriorate. In such a high-power battery 2 in which the state of charge has deteriorated, the time required to charge the capacitor C1 to a predetermined level is longer than in the case where the state of charge is good. In such a case, even if the initial charging voltage Vi of the capacitor C1 is high, the charging relay 6 is turned on before the main relay 5
The time Ton until the device is brought into the conductive state becomes long.

Therefore, as shown in FIG.
1, even when the initial charging voltage Vi is different, the time Ton from the time when the charging relay 6 is turned on to the time when the main relay 5 is turned on depends on the charging state of the high-power battery 2. is there. That is, a characteristic curve S6 shown in FIG. 7 shows a case where the state of charge of the high-power battery 2 is good and the initial charging voltage Vi of the capacitor C1 is small, and a characteristic curve S7 shows that the state of charge of the high-power battery 2 is low. This shows a case where the capacitor C1 has deteriorated and the initial charging voltage Vi of the capacitor C1 is high, and both have substantially the same time Ton.

In such a case, at time t1 shown in FIG.
As can be understood from the changes in the characteristic curves S5 and S6 after 1, the charging voltage Vr at the measurement time t12 has a different value. Therefore, considering the state of deterioration of the battery, when the time Ton is the same, f (T) of the above-described equation (1) is changed according to the magnitude of the initial charging voltage Vi of the capacitor C1. Need to be changed.

In the present embodiment, a process of calculating the subtraction number “T” of the function f (T) is performed using the following equation (2).

T = Ton + g (Vi) (2) However, as shown in FIG. 8, the function g (Vi) in the equation (2) gradually increases with the increase of the initial charging voltage Vi. Has changing properties.

Therefore, when the state of deterioration of the high-power battery 2 is also taken into consideration, in the processing of step ST9 shown in FIG. 2, the processing for correcting the time T using the above equation (2) is performed. good. Thus, it is possible to obtain a voltage value according to the state of deterioration of the high-power battery 2.

As described above, the power supply device 1 for an electric vehicle according to the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part has the same function. Any configuration can be used.

For example, as shown in FIG.
Although the controller 9 is used, the controller for battery control and the controller for vehicle control may be separately mounted.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a control device for an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure by a controller shown in FIG. 1;

FIG. 3 is a characteristic diagram showing a change in the charging voltage of the capacitor when the initial charging voltage of the capacitor is small and large.

FIG. 4 is a diagram illustrating a correction voltage ΔV with respect to a time Ton from when the charging relay is turned on to when the main relay is turned on.
FIG. 4 is a characteristic diagram showing changes in

FIG. 5 is a characteristic diagram showing a relationship between an open circuit voltage (OCV) and SOC.

FIG. 6 is a characteristic diagram showing dischargeable power (S4) and chargeable power (S5) with respect to SOC.

FIG. 7 shows a case where the state of charge of the high-power battery is good,
FIG. 9 is a characteristic diagram illustrating a state of change of a charging voltage when the time Ton matches when the battery is deteriorated.

FIG. 8 is a characteristic diagram showing a change in a correction value g (Vi) of a time T with respect to an initial charging voltage Vi of a capacitor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Power supply device 2 Strong battery 3 Power head 4 Voltage sensor (voltage detection means) 5 Main relay 6 Charging relay 7 Negative relay 8 DC-DC converter 9 Controller C1 Voltage stabilizing capacitor R1 Resistance

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G016 CA03 CB11 CB12 CB31 CC01 CC04 CC07 CC10 CC13 CC23 CD10 CD14 5G003 AA04 BA01 CA11 CB06 FA06 GB06 5H030 AA01 AS08 BB21 FF43 FF44 FF52 5H115 PA08 PC06 PG04 PI16 PI29 PV30 PU08 QN02 QN12 SE06 TI05 TR13 TR19 TU06

Claims (8)

[Claims] 1. A charging relay having a resistor connected in series, and a main relay connected in parallel with the charging relay and the resistor.
By making the main relay conductive, an output voltage of the high-power battery of an electric vehicle power supply that prevents an inrush current generated when a voltage is supplied from a high-power battery to a capacitor for voltage stabilization. A voltage calculating method for calculating, wherein after the charging relay is turned on, when the charging voltage of the voltage stabilizing capacitor reaches a predetermined level, the charging relay is turned off and the main relay is turned on. After the charging relay is turned on, a time Ton from when the charging relay is turned on to when the main relay is turned on is measured. After the main relay is turned on, the charging voltage Vr of the capacitor after a predetermined time has passed is measured. Measuring, based on the measurement time Ton and the charging voltage Vr,
A voltage calculation method for a power supply for an electric vehicle, comprising calculating an output voltage of the high-power battery. 2. The method according to claim 1, wherein the output voltage Vc of the high-power battery is obtained by the following equation. Vc = Vr + f (Ton) where f (Ton) is a voltage value uniquely set by time Ton 3. A charging voltage Vi of the capacitor for voltage stabilization immediately before the charging relay is turned on, is measured based on the charging voltage Vi in addition to the measurement time Ton and the charging voltage Vr. 2. The method according to claim 1, wherein the output voltage of the high-power battery is calculated. 4. The voltage calculation method for an electric vehicle power supply according to claim 3, wherein the output voltage Vc of the high-power battery is obtained by the following two equations. Vc = Vr + f (T) T = Ton + g (Vi) where g (Vi) is a time uniquely set by the charging voltage Vi f (T) is a voltage value uniquely set by the time T 5. A high-power battery, and a capacitor for stabilizing an output voltage of the high-power battery, wherein an output voltage of the high-power battery immediately after the charging of the capacitor from the high-power battery is started is corrected, What is claimed is: 1. A power supply device for an electric vehicle for obtaining an output voltage at a stable time, comprising: a main relay interposed between the high-power battery and the capacitor; and a charging relay connected in parallel to the main relay. A series connection circuit of a capacitor and a resistor; voltage detecting means for measuring a charging voltage of the capacitor; at startup, after the charging relay is turned on, the charging voltage of the capacitor reaches a predetermined value; Time T from when the relay is turned on and when the charging relay is turned on to when the main relay is turned on.
on, and further measures the charging voltage Vr of the capacitor after a lapse of a predetermined time after the main relay is turned on, and calculates the output voltage of the high-power battery based on the measuring time Ton and the charging voltage Vr. A power supply device for an electric vehicle, comprising: a controller that performs a calculation. 6. The power supply device for an electric vehicle according to claim 5, wherein the controller obtains an output voltage Vc of the high-power battery by the following equation. Vc = Vr + f (Ton) where f (Ton) is a voltage value uniquely set by time Ton 7. The charging voltage Vi of the capacitor immediately before the charging relay is turned on.
The controller according to claim 5, wherein the controller calculates an output voltage of the high-power battery based on the charging voltage Vi in addition to the measurement time Ton and the charging voltage Vr. Automotive power supply. 8. The power supply device for an electric vehicle according to claim 7, wherein the controller obtains the output voltage Vc of the high-power battery by the following two equations. Vc = Vr + f (T) T = Ton + g (Vi) where g (Vi) is a time uniquely set by the charging voltage Vi f (T) is a voltage value uniquely set by the time T