JP2002281689A - Charging method and charging device of smoothing capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging method and device of a smoothing capacitor which can charge the smoothing capacitor to a prescribed charging voltage level, by using the output voltage of a sub-battery. SOLUTION: A charging voltage VCB of a smoothing capacitor C1 when an ignition has been turned off the last time, a charging voltage VC of the smoothing capacitor C1 when the ignition is turned on this time, and an output voltage VB of a heavy electric battery when the ignition is turned on this time, are measured. A charging finish voltage VCF of the smoothing capacitor C1 is obtained, according to the voltage VB or the voltage VCB, and the smoothing capacitor C1 is charged until the charging voltage reaches the voltages VCF, by stepping up a DC voltage outputted by a sub-battery E2. Thereafter, a main relay R1 is turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging method and a charging device for charging a smoothing capacitor disposed between a high-power battery and an electric device of an electric vehicle.

[0002]

2. Description of the Related Art Generally, an electric vehicle is equipped with a high-power battery for supplying electric power for traveling and a sub-battery for supplying electric power to lighting equipment and other on-vehicle equipment. In addition, since a three-phase AC power source is required to drive the electric motor for traveling, an inverter circuit is installed in the output stage of the high-power battery, and three-phase AC is generated using the inverter circuit. .

FIG. 6 is an explanatory diagram showing a conventional power supply circuit for driving a motor, and shows a state where a charging relay 106 is turned on. As shown in the figure, an inverter circuit 102 is provided on the output side of the high-power battery 101, and an AC voltage output from the inverter circuit 102 is supplied to an electric motor 103 for running the vehicle. ing. A smoothing capacitor 104 for smoothing a DC voltage output from the high-power battery 101 is provided between the high-power battery 101 and the inverter circuit 102.
Is provided. Further, on the output side of the high-power battery 101, a main relay 105 is disposed.
By turning on 05, the smoothing capacitor 104 can be charged and, consequently, the vehicle can start running.

A DC-DC converter 108 for stepping down the output voltage of the high-power battery 101 is provided, and a sub-battery 109 (usually 12 volts) is used by using a DC voltage output from the DC-DC converter 108. ) Can be charged. Further, a voltage sensor 110 for measuring the output voltage of the high-power battery 101 (the charging voltage of the smoothing capacitor 104) is provided.

In such a power supply circuit, when the main relay 105 is turned on, an excessive rush current flows into the smoothing capacitor 104. Therefore, in order to prevent the occurrence of the rush current, a series connection circuit of the charging relay 106 and the charging resistor 107 is connected to the main relay 105
To the main relay 1
In a state where 05 is turned off, the charging relay 106 is turned on. As a result, a current flows through the loop indicated by the arrow Y101 in FIG. Thereafter, by turning off the charging relay 106 and turning on the main relay 105, a current flows in a loop indicated by an arrow Y102 in FIG. 7 and the smoothing capacitor 104 can be charged to a predetermined level. A stable voltage can be supplied.

However, in the above-described conventional power supply circuit, the charging relay 10 is used to prevent the occurrence of an inrush current.
6, and the charging resistor 107 must be provided, which increases the circuit scale. In addition, since the number of components increases, much time and effort is required for maintenance. Furthermore, when a current flows through the charging resistor 107, the charging resistor 107 generates heat, so that it is necessary to improve the heat resistance of peripheral parts such as a harness. If the ignition switch is frequently turned on and off, the power supply to the charging resistor 107 is repeated, so that the temperature of the charging resistor 107 continues to rise.
Needs to be enlarged.

[0007]

As described above, in a conventional power supply circuit for an electric vehicle, a charging relay 106 and a charging resistor 107 are provided in order to prevent a rush current generated when an ignition switch is turned on. Therefore, the circuit scale becomes large, and the heat resistance of the peripheral components must be improved in order to prevent the influence of the heat generated by the charging resistor 107.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and it is an object of the present invention to make the peripheral parts need to have high heat resistance without increasing the circuit scale. It is another object of the present invention to provide a smoothing capacitor charging method and a smoothing capacitor charging device capable of charging a smoothing capacitor.

[0009]

In order to achieve the above object, the invention according to claim 1 of the present application is to provide a smoothing capacitor disposed between an electric motor mounted on an electric vehicle and an electric motor with the electric power. A charging method for previously setting the smoothing capacitor to a charged state when applying a DC voltage supplied from a battery, and measuring a charging voltage V _CB of the smoothing capacitor when the ignition is turned off last time. steps and, the steps of measuring the charging voltage V _C of the smoothing capacitor when the ignition oN time, and measuring the output voltage V _B of the high voltage battery when the ignition turned on this time, the charging voltage _Obtaining a charge completion voltage V _CF for the smoothing capacitor based on either V _CB or the output voltage V _B ; And boosting the voltage supplied from the sub-battery mounted on the electric vehicle until the voltage V _C becomes the charging completion voltage V _CF and charging the smoothing capacitor.

According to a second aspect of the present invention, the charging voltage V
Comparing the _CB and the charging voltage V _C, the step of determining that if the direction of the charging voltage V _CB smaller the smoothing capacitor, or there is an abnormality in the voltage measuring apparatus used in measuring the respective charging voltage It is characterized by having.

According to a third aspect of the present invention, the output voltage V
_B is compared with the charging voltage V _CB , and when the output voltage V _B is smaller, it is determined that there is an abnormality in the smoothing capacitor or the voltage measuring device used when measuring each of the charging voltages. It is characterized by having.

According to a fourth aspect of the present invention, when a DC voltage supplied from the high-power battery is applied to a smoothing capacitor disposed between the high-power battery mounted on the electric vehicle and the electric motor, A charging device for charging the smoothing capacitor, wherein the DC voltage conversion means boosts a DC voltage supplied from a sub-battery; and Charge control means for controlling the charging of the smoothing capacitor to a predetermined level by applying a DC voltage output from the voltage conversion means.

According to a fifth aspect of the present invention, there is provided a voltage detecting means for detecting a charging voltage of the smoothing capacitor and an output voltage of the high-power battery, and the charging control means is detected by the voltage detecting means. A charge completion voltage of the smoothing capacitor is obtained based on a voltage value, and control is performed so as to apply a voltage output from the DC voltage conversion means to the smoothing capacitor so as to reach the charge completion voltage. .

According to a sixth aspect of the present invention, the voltage detecting means includes a charging voltage V _{CB of} the smoothing capacitor when the ignition was previously turned off and an output of the high-power battery when the ignition was turned on this time. measuring the voltage V _B, the charge control unit, the charging voltage V _CB, or based on any of the output voltage V _B, and obtains the charging completion voltage.

According to a seventh aspect of the present invention, the voltage detecting means includes a charging voltage V _{CB of} the smoothing capacitor when the ignition was previously turned off, and a charging voltage of the smoothing capacitor when the ignition was turned on this time. Voltage V
_C , the charging control means compares the charging voltage V _C with the charging voltage V _CB , and when the charging voltage V _CB is smaller, at least one of the smoothing capacitor or the voltage detecting means It is characterized by judging that it is abnormal.

According to the present invention, the voltage detecting means includes a charging voltage V _{CB of} the smoothing capacitor when the ignition was previously turned off and an output of the high-power battery when the ignition was turned on this time. Voltage V _B
The charging control unit compares the charging voltage V _CB with the output voltage V _B , and when the output voltage V _B is smaller, at least one of the smoothing capacitor or the voltage detecting unit It is characterized by judging that it is abnormal.

In the ninth aspect of the present invention, the DC voltage converting means includes a boosting means for boosting an output voltage of the sub-battery to a voltage at which the smoothing capacitor can be charged.
Step-down means for stepping down a DC voltage output from the high-power battery to a voltage at which the sub-battery can be charged.

According to a tenth aspect of the present invention, the step-up unit and the step-down unit each include a switching circuit, a transformer, and a rectifier circuit.

[0019]

According to the first aspect of the present invention, the charging voltage V _CB of the smoothing capacitor when the ignition was turned off last time,
Based on the charging voltage V _C of the smoothing capacitor when the ignition is turned on this time and the output voltage V _B of the strong current battery when the ignition is turned on this time, the charging completion voltage V _CF is obtained, and the charging voltage of the smoothing capacitor is calculated. Until the charging completion voltage V _CF is reached, the smoothing capacitor is charged using the output voltage of the sub-battery, so that there is no need to use a charging relay or a charging resistor as in the related art, and the circuit scale can be reduced. And the amount of generated heat can be suppressed.

[0020] In the present invention of claim 2, than the charging voltage V _BC, it is larger in the charging voltage V _C, because not be a normal operation, it charging voltage V _C is greater than the charging voltage V _BC Is detected, by notifying that the voltage detecting means or the smoothing capacitor is abnormal,
A malfunction of the circuit can be notified beforehand.

According to the third aspect of the present invention, the fact that the charging voltage V _C is higher than the output voltage V _B cannot be a normal operation, so that the charging voltage V _BC is higher than the output voltage V _B. Is detected, it is notified that the voltage detecting means or the smoothing capacitor is abnormal, so that a malfunction of the circuit can be prevented.

According to the fourth aspect of the invention, before the smoothing capacitor is charged by the high-power battery, the smoothing capacitor is set to a predetermined voltage by using the DC voltage obtained by boosting the output voltage of the sub-battery by the DC voltage converter. Since the battery is charged to the level, it is possible to prevent the occurrence of inrush current when the output voltage of the high-power battery is applied. Further, since a charging relay and a charging resistor are not used as in the related art, the circuit scale can be reduced, and the problem that the charging resistor generates heat can be avoided.

According to the fifth aspect of the present invention, since the charging completion voltage of the smoothing capacitor is set based on the voltage value detected by the voltage detecting means, the charging voltage immediately before supplying the output voltage of the high-power battery is preferably set. Level.

According to the sixth aspect of the present invention, based on the charging voltage V _CB of the smoothing capacitor when the ignition is off or the output voltage V _B of the high-power battery when the ignition is on,
Since the charge completion voltage is obtained, the charge level of the smoothing capacitor can be set to a suitable level.

According to the present invention, when it is detected that the charging voltage V _C is higher than the charging voltage V _BC , the voltage detecting means or the smoothing capacitor is notified that the circuit is abnormal. Can be notified beforehand.

According to the present invention, when it is detected that the charging voltage V _BC is higher than the output voltage V _B , it is notified that the voltage detecting means or the smoothing capacitor is abnormal, and the circuit is turned off. Malfunction can be prevented beforehand.

According to the ninth aspect of the present invention, since the DC voltage converting means includes the step-up means and the step-down means, the output voltage of the sub-battery can be boosted to a voltage at which the smoothing capacitor can be charged. The output voltage of the battery
The voltage can be reduced to a voltage at which the sub-battery can be charged.

According to the tenth aspect of the present invention, the step-up means and the step-down means are composed of a switching circuit, a transformer, and a rectifier circuit, so that the step-up or step-down can be performed to a desired voltage. Become.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a power supply circuit for an electric vehicle including a charging device for a smoothing capacitor according to an embodiment of the present invention, and shows a state where a main relay R1 is turned off. Note that the electric vehicle in the present embodiment is a broad concept including a hybrid vehicle.

The power supply circuit shown in FIG.
, An electric motor M1 for driving the vehicle, and a high-power battery E1
The DC voltage output from the inverter circuit 11 is converted into a three-phase AC voltage and supplied to the electric motor M1, and the DC voltage output from the high-power battery E1 is provided at a stage preceding the inverter circuit 11 and is smoothed. Smoothing capacitor C1
And a main relay R1 that is provided on the output side of the high-power battery E1 and that switches on and off the voltage output from the high-power battery E1.

Further, a voltage sensor (voltage detection means) 12 for measuring an output voltage of the high-power battery E1 (a charging voltage of the smoothing capacitor C1), a sub-battery E2 for outputting a DC voltage of, for example, 12 V, Sub battery E
DC-D which supplies the charging voltage to the sub-battery E2 by stepping up the output voltage of No. 2 and charging the smoothing capacitor C1, and stepping down the DC voltage output from the high-power battery E1.
A C converter (DC voltage conversion means) 13 and a controller (charge control means) 14 for controlling the main relay R1 and the DC-DC converter 13 according to the voltage value detected by the voltage sensor 12 are provided.

FIG. 2 is a block diagram showing a detailed configuration of the DC-DC converter 13, showing a state in which the output voltage of the sub-battery E2 charges the smoothing capacitor C1. As shown, the DC-DC converter 13
A step-up switching circuit 21 that converts a DC voltage (for example, 12 volts) supplied from the sub-battery E2 into an AC voltage, a step-up control circuit 22 that outputs a switching pulse signal to the step-up switching circuit 21, A boosting transformer 23 for boosting the AC voltage output from the switching circuit 21 and a boosting rectifier circuit 24 for rectifying the AC voltage boosted by the boosting transformer 23 are provided.

Further, the DC-DC converter 13 includes a step-down switching circuit 25 for converting a DC voltage output from the high-power battery E1 into an AC voltage, and a step-down control for outputting a switching pulse signal to the step-down switching circuit 25. The circuit includes a circuit 26, a step-down transformer 27 that steps down the AC voltage output from the step-down switching circuit 25, and a step-down rectifier circuit 28 that rectifies the AC voltage stepped down by the step-down transformer 27.

Next, the operation of the present embodiment configured as described above will be described with reference to the flowchart shown in FIG. When the ignition of the vehicle is turned off (step ST1), the charging voltage V _CB of the smoothing capacitor C1 when the ignition is turned off is measured and stored by the voltage sensor 12 (step ST2). Thereafter, when the ignition is turned on (step ST3), the measurement of the charging voltage V _C of the smoothing capacitor C1 by the voltage sensor 12 is started (step ST4).

Next, the controller 14 compares the charging voltage V _CB when the ignition is off with the charging voltage V _C measured when the ignition is on (step ST).
5), if the voltage V _C is greater than the voltage V _CB (NO in step ST5), the smoothing capacitor C1, or one of the voltage sensor 12 is abnormal (step ST6). That is, it cannot be a normal operation that the charging voltage V _C when the ignition is turned on this time is higher than the charging voltage V _CB of the smoothing capacitor C 1 when the ignition was turned off last time. It is determined that either the smoothing capacitor C1 or the voltage sensor 12 is abnormal.

On the other hand, if voltage V _CB is higher than voltage V _C (YES in step ST5), output voltage V _B of high-power battery E1 is measured (step ST7). And
The controller 14 compares the voltage V _B and the voltage V _CB (step ST8), (NO in step ST8). If a larger voltage V _CB, one of the smoothing capacitor C1 or voltage sensor 12, abnormality Is determined (step ST6). In this case, as in the above, if the operation is normal, V _B should be higher than V _CB ,
If this is not satisfied, it is determined that either the smoothing capacitor C1 or the voltage sensor 12 is abnormal.

If the voltage V _B is equal to or higher than the voltage V _CB (YES in step ST8), the voltage V _B or the voltage V
The charge completion voltage V _CF of the smoothing capacitor C1 is calculated based on the voltage value of _CB (step ST9). The charge completion voltage V _CF can be determined by, for example, V _B (or V _CB ) − (fixed value), and the fixed value is, for example, 20 volts.

Thereafter, charging of the smoothing capacitor C1 is started using the voltage output from the sub-battery E2 (step ST10). That is, under the control of the controller 14, the boost control circuit 22 of the DC-DC converter 13 shown in FIG. 2 outputs a switching pulse signal,
Since the boosting switching circuit 21 operates by the pulse signal, the DC voltage output from the sub-battery E2 is converted into an AC voltage.

The AC voltage is supplied to the step-up transformer 2
3, the voltage is boosted by the booster rectifier circuit 24, applied to the smoothing capacitor C1, and charging is started. At this time, a current flows in a loop indicated by an arrow Y1 in FIG. 1, and an electric signal flows in a direction indicated by an arrow Y2 in FIG. Then, it increases the charging voltage of the smoothing capacitor C1 over time, the charge voltage V _C is the charging completion voltage V _CF more (YES in step ST11), the step-up control circuit 2
2 to stop the pulse output, and terminate the charging operation for the smoothing capacitor C1 (step ST12). afterwards,
By turning on the main relay R1 shown in FIG.
The output voltage from the high-power battery E1 is converted to a smoothing capacitor C1.
(Step ST13). That is, current flows in the loop indicated by arrow Y3 in FIG.

At this time, since the charging voltage of the smoothing capacitor C1 has already reached the predetermined voltage V _CF , it is possible to prevent an excessive rush current from flowing through the circuit when the main relay R1 is turned on. it can.

After that, the DC voltage output from the high-power battery E1 is converted into a three-phase AC voltage by the inverter circuit 11, so that the electric motor M
1 can be driven to rotate.

When the voltage capacity of the sub-battery E2 decreases, the step-down control circuit 26 is operated under the control of the controller 14, and a pulse signal is output to the step-down switching circuit 25. As a result, the DC voltage output from the high-power battery E1 is converted into an AC voltage, and further reduced by the step-down transformer 27. Next, the step-down rectifier circuit 28
Is reduced to a DC voltage at a level at which the sub-battery E2 can be charged.
Can be charged. That is, the electric signal flows in the direction indicated by arrow Y4 in FIG.

As described above, in the smoothing capacitor charging apparatus according to the present embodiment, before turning on the main relay R1, the smoothing capacitor C1 is previously set to the predetermined voltage (V) using the output voltage of the sub-battery E2. _CF ), the occurrence of inrush current flowing when the main relay R1 is turned on can be avoided.

As a result, there is no need to install a charging resistor for preventing an inrush current as in the prior art, and it is possible to avoid the influence of heat generation on surrounding components.

The charge voltage V when the ignition is off
Compared with _BC, the charging voltage V _C at the time of ignition ON, if the direction of the voltage V _C greater, or the charging voltage V _CB
Is compared with the output voltage V _B of the high-power battery E1, and the voltage V
_{If CB} is larger, it is detected that either the voltage sensor 12 or the smoothing capacitor C1 is abnormal, so that malfunction can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a power supply circuit including a charging device for a smoothing capacitor according to an embodiment of the present invention, showing a state when a main relay is turned off.

FIG. 2 is a block diagram showing a detailed configuration of a DC-DC converter, showing how a smoothing capacitor is charged using a voltage output from a sub-battery.

FIG. 3 is a flowchart showing a processing procedure by a controller of the charging device for the smoothing capacitor according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a power supply circuit including a charging device for a smoothing capacitor according to an embodiment of the present invention, showing a state when a main relay is turned on.

FIG. 5 is a block diagram showing a detailed configuration of a DC-DC converter, and shows how a sub-battery is charged using a voltage output from a high-power battery.

FIG. 6 is an explanatory diagram showing a configuration of a conventional power supply circuit, and shows a state when a charging relay is turned on.

FIG. 7 is an explanatory diagram showing a configuration of a conventional power supply circuit, showing a state when a main relay is turned on.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Inverter circuit 12 Voltage sensor (voltage detection means) 13 DC-DC converter (DC voltage conversion means) 14 Controller (charge control means) 21 Step-up switching circuit 22 Step-up control circuit 23 Step-up transformer 24 Step-up rectifier circuit 25 Step-down switching circuit 26 Step-down Control circuit 27 Step-down transformer 28 Step-down rectifier circuit E1 High-power battery M1 Electric motor C1 Smoothing capacitor R1 Main relay

Claims (10)

[Claims] When applying a DC voltage supplied from a high-power battery to a smoothing capacitor disposed between a high-power battery mounted on an electric vehicle and an electric motor,
A charging method for previously bringing the smoothing capacitor into a charged state, wherein a step of measuring a charging voltage V _CB of the smoothing capacitor when the ignition is turned off last time; and a step of measuring the charging voltage when the ignition is turned on this time. Measuring the charging voltage V _{C of the} capacitor; measuring the output voltage V _B of the high-power battery when the ignition is turned on this time; based on either the charging voltage V _CB or the output voltage V _B Calculating the charging completion voltage V _CF to the smoothing capacitor by the step of: increasing the voltage supplied from the sub-battery mounted on the electric vehicle until the charging voltage V _C becomes the charging completion voltage V _CF Charging the smoothing capacitor; and charging the smoothing capacitor. 2. The charging voltage V _CB is compared with the charging voltage V _{C. If} the charging voltage V _CB is smaller, the voltage measuring device used when measuring the smoothing capacitor or each of the charging voltages. 2. The method for charging a smoothing capacitor according to claim 1, further comprising the step of determining that there is an abnormality. 3. The output voltage V _B is compared with a charging voltage V _CB , and when the output voltage V _B is smaller, a voltage measuring device used for measuring the smoothing capacitor or each of the charging voltages. 3. The method for charging a smoothing capacitor according to claim 1, further comprising a step of determining that there is an abnormality. 4. When applying a DC voltage supplied from the high-power battery to a smoothing capacitor disposed between the high-power battery mounted on the electric vehicle and the electric motor,
A charging device for setting the smoothing capacitor in a charged state in advance, comprising: a DC voltage conversion unit configured to boost a DC voltage supplied from a sub-battery; and Charge control means for controlling the charging of the smoothing capacitor to a predetermined level by applying a DC voltage output from the DC voltage converting means. 5. A voltage detecting unit for detecting a charging voltage of the smoothing capacitor and an output voltage of the high-power battery, wherein the charging control unit is configured to detect the charging voltage based on a voltage value detected by the voltage detecting unit. The smoothing capacitor according to claim 4, wherein a charging completion voltage of the smoothing capacitor is obtained, and the voltage output from the DC voltage conversion means is controlled so as to be applied to the smoothing capacitor so as to reach the charging completion voltage. Capacitor charging device. 6. The voltage detecting means measures a charging voltage V _{CB of} the smoothing capacitor when the ignition is turned off last time and an output voltage V _B of the high-power battery when the ignition is turned on this time, The charging device for a smoothing capacitor according to claim 5, wherein the charging control means obtains the charging completion voltage based on either the charging voltage V _CB or the output voltage V _B. 7. The voltage detecting means measures a charging voltage V _{CB of} the smoothing capacitor when the ignition is turned off last time and a charging voltage V _C of the smoothing capacitor when the ignition is turned on this time, The charging control means compares the charging voltage V _C with the charging voltage V _CB ,
7. The smoothing capacitor according to claim 5, wherein when the charging voltage V _CB is smaller, it is determined that at least one of the smoothing capacitor and the voltage detecting unit is abnormal. Charging device. 8. The voltage detecting means measures a charging voltage V _{CB of} the smoothing capacitor when the ignition is turned off last time and an output voltage V _B of the high-power battery when the ignition is turned on this time, The charging control unit compares the charging voltage V _CB with the output voltage V _B , and when the output voltage V _B is smaller, it is determined that at least one of the smoothing capacitor or the voltage detecting unit is abnormal. A judgment is made.
The charging device for a smoothing capacitor according to any one of the preceding claims. 9. The DC voltage converter includes a booster that boosts an output voltage of the sub-battery to a voltage that can be charged to the smoothing capacitor; and a DC voltage output from the high-power battery to the sub-battery. The charging device for a smoothing capacitor according to any one of claims 4 to 8, further comprising a step-down unit configured to step down to a chargeable voltage. 10. The step-up means and the step-down means,
A switching circuit, a transformer, a rectifier circuit,
The charging device for a smoothing capacitor according to claim 9, comprising: