JPWO2017033411A1 - Power supply device and electric vehicle equipped with this power supply device - Google Patents

Abstract

  In order to reliably detect abnormality of the capacitor connected in parallel with the load and its connection circuit, the power supply device supplies power to the load (20) in which the capacitor (9) is connected in parallel to the input side. The battery (1), the output switch (3) electrically connected between the battery (1) and the load (20), and the capacitor of the load (20) when the output switch (3) is off. And a precharge circuit (4) for precharging (9). The precharge circuit (4) has a sub-battery (11) whose output voltage is lower than that of the battery (1), and a booster circuit (5) for boosting the output of the sub-battery (11) and precharging the capacitor (9). And. Furthermore, the power supply device includes an abnormality detection circuit (7) that determines abnormality of the capacitor (9) or its connection circuit from the voltage rise characteristic of the capacitor (9) precharged by the precharge circuit (4).

Description

  The present invention relates to a power supply device including a capacitor precharge circuit connected in parallel with a load, and relates to a power supply device that detects an abnormality of the capacitor and its connection circuit, and an electric vehicle including the power supply device.

  A load to which DC power is supplied from the battery is connected to a capacitor in parallel, so that power is stably supplied while reducing battery voltage fluctuation. In order to realize this, for example, in a power supply device for a vehicle, a capacitor is connected in parallel to a vehicle load. Furthermore, in the power supply device, an output switch such as a relay or a semiconductor switching element is provided, and a capacitor and a load are connected to the battery. The output switch is turned on when the battery is connected to the load, and turned off when the battery is not connected to the load. In a power supply device for a vehicle, the output switch is turned on and off in conjunction with an on / off of an ignition switch that is a main switch of the vehicle. In other words, the output switch is turned on when the ignition switch is on, and the output switch is turned off when the ignition switch is off. In such a power supply device, when the output switch is turned on, the capacitor is charged, so that a very large charge current instantaneously flows immediately after connection. Excessive charge current causes damage to the relay contacts of the output switch or causes the semiconductor switching element to fail.

  In order to prevent this problem, a power supply device has been developed in which a precharge circuit is provided, a capacitor is precharged via the precharge circuit, and then an output switch is turned on (see Patent Documents 1 and 2). .

JP 2009-290978 A JP 2009-38925 A

  In the power supply devices described in these publications, the precharge circuit is configured by a series circuit of a precharge switch and a precharge resistor connected in parallel to one output switch. In this power supply device, the precharge circuit is turned on with the output switch connected in parallel with the precharge circuit turned off, the capacitor is precharged by the precharge circuit, and then the output switch is turned on. Thus, an excessive charge current in the ON state of the output switch can be suppressed.

  However, the capacitor provided on the vehicle side has a large capacity, and the precharge control also has a large change in voltage behavior during precharge depending on the state of the capacitor on the vehicle side. There was a problem that it was not easy. In addition, because the capacitor on the vehicle side is precharged with the power supplied from the battery, the voltage and charging current during precharging change depending on the state of the battery, so it is possible to reliably detect abnormalities in the capacitor and its connection circuit. There was a problem that it was not easy.

  The present invention has been made to solve the conventional drawbacks. An object of the present invention is to provide a power supply device that can reliably detect an abnormality in a capacitor connected in parallel with a load and a connection circuit thereof, and an electric vehicle including the power supply device.

Means for Solving the Problems and Effects of the Invention

  The power supply device of the present invention includes a battery 1 that supplies power to a load 20 having a capacitor 9 connected in parallel on the input side, and an output switch 3 that is electrically connected between the battery 1 and the load 20. And a precharge circuit 4 that precharges the capacitor 9 of the load 20 when the output switch 3 is in an OFF state. The precharge circuit 4 includes a sub-battery 11 having an output voltage lower than that of the battery 1 and a booster circuit 5 that boosts the output of the sub-battery 11 and precharges the capacitor 9. The power supply device further includes an abnormality detection circuit 7 that determines an abnormality of the capacitor 9 or its connection circuit from the voltage rise characteristics of the capacitor 9 precharged by the precharge circuit 4.

  With the above configuration, when the precharge circuit precharges the capacitor, it can be reliably determined whether the capacitor or its connection circuit is in a normal state or an abnormal state. In this power supply device, the precharge circuit is composed of a sub-battery whose output voltage is lower than that of the battery, and a booster circuit that boosts the output of the sub-battery to precharge the capacitor. This is because the abnormality detection circuit determines the abnormality of the capacitor or its connection circuit from the voltage rise characteristics of the capacitor. In this power supply device, since the precharge circuit boosts the output of the sub-battery by the booster circuit and precharges the capacitor, it can be stably precharged without being affected by the state of the battery as in the prior art. As a result, the abnormality of the capacitor or its connection circuit can be reliably determined from the voltage rise characteristics of the capacitor during precharging.

  In the power supply device of the present invention, the sub-battery can be a 12V lead battery. Since this power supply device uses a general-purpose 12V lead battery, the output of the precharge circuit is widened from a low voltage to a high voltage by boosting the 12V output with a booster circuit while facilitating the handling. Can be controlled by range. In particular, in a power supply device mounted on a vehicle, a lead battery mounted on the vehicle can be conveniently used as a sub-battery as an electrical equipment battery.

  A power supply device according to another aspect of the present invention is electrically connected between a battery 1 that supplies power to a load 20 having a capacitor 9 connected in parallel on the input side, and the battery 1 and the load 20. Output switch 3 and a precharge circuit 4 that precharges the capacitor 9 of the load 20 when the output switch 3 is in an off state. The precharge circuit 4 steps down the output voltage of the battery 1 to reduce the capacitor 9 Is provided. The power supply device further includes an abnormality detection circuit 7 that determines an abnormality of the capacitor 9 or its connection circuit from the voltage rise characteristics of the capacitor 9 precharged by the precharge circuit 4.

  With the above configuration, when the precharge circuit precharges the capacitor, it can be reliably determined whether the capacitor or its connection circuit is in a normal state or an abnormal state. In this power supply device, the precharge circuit is composed of a step-down circuit that steps down the output of the battery and precharges the capacitor. From the voltage rise characteristics of the capacitor that is precharged by the step-down circuit, the abnormality detection circuit is a capacitor or This is because the abnormality of the connection circuit is determined. In this power supply device, since the precharge circuit steps down the output of the battery by the step-down circuit and precharges the capacitor, it can be stably precharged without being affected by the state of the battery as in the prior art. As a result, the abnormality of the capacitor or its connection circuit can be reliably determined from the voltage rise characteristics of the capacitor during precharging.

  In the power supply device of the present invention, when the abnormality detection circuit 7 calculates the voltage increase rate from the increased voltage of the precharged capacitor 9 and the precharge time, and the voltage increase rate is within a predetermined normal range, the capacitor 9 and its connection circuit can be determined to be normal and precharge can be continued.

  With the above configuration, the voltage rise rate is calculated from the rise voltage and precharge time of the capacitor to be precharged, and by comparing this voltage rise rate with the normal range, it is easy and reliable whether the capacitor or its connection circuit is abnormal. Can be determined.

In the power supply device of the present invention, when the abnormality detection circuit 7 has a voltage increase rate higher than the maximum increase rate set higher than the upper limit of the normal range, it is determined that the capacitor 9 or the connection circuit has an open failure and precharge is performed. Can be stopped.
In this specification, the “open failure of a capacitor or a connection circuit” means a state in which the circuit is not normally connected due to disconnection or poor contact of the capacitor or its connection circuit.

  With the above-described configuration, it is possible to detect an open failure when the precharged capacitor shows a rapid voltage rise, and it is possible to grasp the abnormal state and take appropriate measures.

  In the power supply device of the present invention, the abnormality detection circuit 7 determines that the capacitor 9 has deteriorated when the voltage increase rate is higher than the upper limit of the normal range and below the maximum increase rate set higher than the upper limit of the normal range. can do.

  With the above configuration, the voltage of the precharged capacitor rises faster than the normal state, so that it is possible to determine that the capacitor has deteriorated, particularly deterioration due to a decrease in capacity, and take appropriate measures.

  In the power supply device of the present invention, the abnormality detection circuit 7 determines that the capacitor 9 has deteriorated when the voltage increase rate is lower than the lower limit of the normal range and equal to or higher than the minimum increase rate set lower than the lower limit of the normal range. can do.

  With the above configuration, when the voltage of the precharged capacitor rises later than normal, it is possible to determine that the capacitor has deteriorated, particularly deterioration due to an increase in internal resistance, and take appropriate measures. .

  In the power supply device of the present invention, if the voltage of the capacitor 9 does not increase even after a predetermined time has elapsed after the abnormality detection circuit 7 starts precharging, it is determined that the capacitor 9 or the connection circuit is short-circuited and precharged. Can be stopped.

  With the above configuration, it is possible to detect a short-circuit failure when the voltage of the capacitor does not rise even after precharging is started, and it is possible to grasp the abnormal state and take appropriate measures.

  In the power supply device of the present invention, the output voltage at which the precharge circuit 4 precharges the capacitor 9 is divided into two stages: a second charge voltage according to the output voltage of the battery 1 and a first charge voltage lower than the second charge voltage. When the abnormality detection circuit 7 determines that the capacitor 9 and its connection circuit are normal, the output voltage is switched to the second charging voltage. 9 can be precharged.

  With the above configuration, the abnormality of the capacitor or its connection circuit is determined in the precharge at the first charging voltage lower than the output voltage of the battery. Therefore, the abnormality can be determined without increasing the capacitor voltage, and the abnormality of the capacitor or its connection circuit can be determined. The danger at the time can be avoided. Also, by suppressing the voltage at the start of precharge to a low level, it is possible to effectively prevent the output voltage of the precharge circuit from rising immediately after the start of precharge and exceeding the allowable withstand voltage on the load side.

  In the power supply device of the present invention, the output voltage at which the precharge circuit 4 precharges the capacitor 9 is divided into two stages: a second charge voltage according to the output voltage of the battery 1 and a first charge voltage lower than the second charge voltage. When the abnormality detection circuit 7 determines that the capacitor 9 has deteriorated, the output voltage is switched to the second output voltage without stopping the precharge. You can continue to precharge and conditionally allow its use.

  With the above configuration, when the abnormality detection circuit determines that the capacitor has deteriorated in the precharge with the first charging voltage lower than the output voltage of the battery, the output voltage is not stopped depending on the degree of the deterioration of the capacitor without stopping the precharge. Can be switched to the second output voltage to continue precharging and allow its use conditionally. For example, the capacitor deteriorates and cannot fully satisfy the function as a smoothing capacitor. However, when the capacitor can be used for a short time, the precharge can be continued and allowed to be used.

  In the power supply device of the present invention, when the precharge circuit 4 sets the first output voltage to 60 V or less and the abnormality detection circuit 7 detects an abnormality in a state where the precharge is performed with the first output voltage, the load 20 The precharge to the capacitor 9 can be stopped. With the above configuration, by setting the first output voltage to 60 V or less as the first stage, even if an abnormality is detected in the first stage and the precharge is interrupted, it is not classified as a high voltage. It becomes unnecessary. Therefore, the circuit configuration can be simplified and the cost can be reduced.

  The power supply device of the present invention is a power supply device mounted on an electric vehicle, and a load 20 to which electric power is supplied from a battery 1 supplies a motor 22 for running the vehicle and electric power from the battery 1 to the motor 22. The capacitor 9 including the DC / AC inverter 21 and connected in parallel to the input side can be a smoothing capacitor provided on the input side of the DC / AC inverter 21.

The electric vehicle of the present invention includes any one of the power supply devices described above, and the power supply device can supply power to the motor 22 that causes the vehicle to travel.
With the above configuration, when the capacitor is precharged by the power supply device mounted on the electric vehicle, the abnormality of the capacitor or its connection circuit is reliably detected, and the precharge is stopped or the vehicle side is warned according to the degree of the abnormality. Thus, safe traveling of the electric vehicle can be realized.

It is a block diagram which shows an example of the power supply device which concerns on one embodiment of this invention. It is a block diagram which shows an example of the power supply device which concerns on other embodiment of this invention. It is a graph which shows the voltage rise characteristic of the capacitor | condenser precharged. It is a figure which shows the change of a capacitor voltage in a state with a normal capacitor | condenser and its connection circuit, and a timing chart. It is a figure which shows the change of a capacitor voltage, and a timing chart in the state which the capacitor deteriorated and the capacity | capacitance fell. It is a figure which shows the change of a capacitor voltage, and a timing chart in the state in which the capacitor | condenser or its connection circuit failed open. It is a figure which shows the change of a capacitor voltage, and a timing chart in the state which the capacitor deteriorated and internal resistance increased. It is a figure which shows the change of a capacitor voltage, and a timing chart in the state where a capacitor or its connection circuit failed. It is a block diagram which shows the example which mounts a power supply device in the hybrid car which drive | works with an engine and a motor. It is a block diagram which shows the example which mounts a power supply device in the electric vehicle which drive | works only with a motor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a power supply device for embodying the technical idea of the present invention and an electric vehicle equipped with the power supply device. The present invention includes the power supply device and the power supply device. The electric vehicle provided is not specified as follows. Further, the present specification by no means specifies the member shown in the claims as the member of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the embodiments are not intended to limit the scope of the present invention only to a specific description unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are configured by the same member and the plurality of elements are shared by the same member, and conversely, the function of the same member is configured by a plurality of members. It can also be realized by sharing.

  As an example of the power supply apparatus according to the present invention, an example in which the present invention is applied as a power source of an electric vehicle using a drive motor of a hybrid vehicle, a plug-in hybrid vehicle, or an electric vehicle as a load is shown in FIGS. The power supply device of the present invention is not limited to an electric vehicle, and can be applied to a load using a motor, for example, a robot or an industrial production machine. Further, the present invention is not limited to a motor, and can be used for all power supply devices that supply power to a load in which capacitors are connected in parallel.

(Power supply devices 100 and 200)
1 and FIG. 2 includes a battery 1, an output switch 3, and a precharge circuit 4. The battery 1 has a plurality of batteries 2 connected in series. This battery 1 is connected to a load 20 via an output switch 3. The precharge circuit 4 precharges the capacitor 9 connected in parallel to the input side of the load 20 before the output switch 3 is turned on, that is, in the off state of the output switch 3. Furthermore, the power supply apparatuses 100 and 200 shown in the figure include an abnormality detection circuit 7 that detects an abnormality of the capacitor 9 or its connection circuit and controls the on / off of the output switch 3 and the operating state of the precharge circuit 4.

(Load 20)
The load 20 shown in FIGS. 1 and 2 includes a DC / AC inverter 21, and a motor 22 and a generator 23 connected to the output side of the DC / AC inverter 21. The DC / AC inverter 21 converts the direct current of the battery 1 into alternating current and supplies electric power to the motor 22, and converts the alternating current of the generator 23 into direct current to charge the battery 1.

  In the above example, the motor 22 is connected via the DC / AC inverter 21 as the load 20 driven by the power supply device. However, when a direct-current-driveable load such as a direct-current motor is directly connected, the DC The / AC inverter can be omitted. A load driven by direct current can also supply power via a DC / DC converter.

(Condenser 9)
A capacitor 9 is connected in parallel to the input side of the load 20. A capacitor 9 connected in parallel to the input side is a smoothing capacitor provided on the input side of the DC / AC inverter 21. The capacitor 9 is a large-capacity electrolytic capacitor having an electrostatic capacity of, for example, 300 μF to 3000 μF. Electrolytic capacitors can increase capacitance with respect to volume. As the capacitor, another capacitor having a large capacitance such as a multilayer ceramic capacitor can be used instead of the electrolytic capacitor. Note that the capacitor 9 may fail due to a decrease in capacitance over time, or a failure due to a sudden decrease in capacitance, or a failure due to an increase in internal resistance due to deterioration over time. .

(Battery 1)
The battery 1 supplies power to the load 20. 1 and 2 supplies electric power from the battery 1 to the motor 22 via the DC / AC inverter 21. The battery 1 is charged by the generator 23 via the DC / AC inverter 21. In order to supply a large amount of power to the motor 22 of the load 20, the battery 1 has a large number of batteries 2 connected in series to increase the output voltage. Further, the battery can have a large charge capacity by connecting a plurality of batteries in parallel. The battery 2 is a non-aqueous electrolyte battery such as a lithium ion battery or a lithium polymer battery, or a secondary battery such as a nickel metal hydride battery. However, any other secondary battery that can be charged and discharged can be used as the battery. The battery 1 has an output voltage as high as 200 to 400 V, for example, so that large power can be supplied to the load 20.

  A battery 1 shown in FIGS. 1 and 2 divides a number of batteries 2 into two battery blocks, and these battery blocks are connected in series with each other. A protection element 18 and a current sensor 19 are connected in series between the battery blocks connected in series. The protection element 18 shown in the figure is a fuse, which is blown when an overcurrent flows, interrupts the current, and protects the battery 1.

(Output switch 3)
The output switch 3 is a switch that is electrically connected between the battery 1 and the load 20. The output switch 3 is controlled to be turned on / off by the abnormality detection circuit 7 to control the energization state of the battery 1 and the load 20. The output switch 3 shown in the figure includes a first output switch 3A connected between the positive electrode side of the battery 1 and the positive output terminal 10, a negative electrode side of the battery 1, and a negative output terminal 10. And a second output switch 3B connected between the two. However, the power supply device does not necessarily need to connect the output switch 3 to the positive and negative output sides, and can connect the output switch to one output side. In the power supply device shown in the figure, the output switch 3 is a relay having a contact that is mechanically movable. However, as the output switch, instead of the relay, another switch capable of controlling on / off of the energization state of the semiconductor switching element or the like can be used.

(Precharge circuit 4)
The precharge circuit 4 precharges the large-capacitance capacitor 9 connected to the input side of the load 20 before the output switch 3 is turned on, and an excessive inrush current flows through the output switch 3. Stop. The precharge circuit 4 shown in FIGS. 1 and 2 has a circuit configuration capable of precharging the capacitor 9 with a predetermined voltage.

  The precharge circuit 4 shown in FIG. 1 includes a sub-battery 11 having an output voltage lower than that of the battery 1 and a booster circuit 5 that boosts the output of the sub-battery 11 and precharges the capacitor 9.

  The sub-battery 11 is a battery for electrical equipment mounted on a vehicle, and is a 12V lead battery 11A. Since this structure generally uses an electric lead battery 11A mounted on a vehicle as the sub-battery 11, the cost can be reduced without preparing another battery. Further, since the lead battery 11A mounted on the vehicle is always charged in the usage state of the vehicle, the situation where the battery capacity is insufficient when supplying power to the booster circuit 5 as the power source of the precharge circuit 4 is effective. Can be prevented. However, the sub-battery can be equipped with another battery without using an electric battery mounted on the vehicle. This sub-battery is preferably secured as a secondary battery with a predetermined capacity by charging.

  The booster circuit 5 is a boost converter 5 </ b> A that boosts the power supplied from the sub-battery 11. The step-up converter 5A is a DC / DC converter, the positive output is connected between the first output switch 3A and the positive output terminal 10, and the negative output is negative with the second output switch 3B. And the output terminal 10 on the side. The boost converter 5A is controlled to be turned on and off by the abnormality detection circuit 7, boosts DC12V input from the sub-battery 11 to a predetermined voltage, and outputs the voltage, thereby precharging the capacitor 9.

  Further, the precharge circuit 4 shown in FIG. 2 includes a step-down circuit 6 that steps down the output voltage of the battery 1 and precharges the capacitor 9. The step-down circuit 6 is a step-down converter 6A that steps down the power supplied from the battery 1. The step-down converter 6A is a DC / DC converter, the positive output is connected between the first output switch 3A and the positive output terminal 10, and the negative output is negative with the second output switch 3B. And the output terminal 10 on the side. This step-down converter 6 </ b> A is controlled to be turned on and off by the abnormality detection circuit 7, steps down a high-voltage DC voltage input from the battery 1 to a predetermined voltage, and precharges the capacitor 9.

  The precharge circuit 4 described above precharges the capacitor 9 in a state where the output switch 3 is turned off. When the capacitor 9 is precharged to a predetermined voltage, the step-up converter 5A and the step-down converter 6A are switched to the OFF state, and then the output switch 3 is switched from OFF to ON, so that the battery 1 is connected to the load 20. . Since the capacitor 9 is precharged and switched to the ON state, the output switch 3 does not flow an excessive charge current for charging the capacitor 9. The timing at which the boost converter 5A and the step-down converter 6A are switched off and the timing at which the output switch 3 is switched on are controlled by the abnormality detection circuit 7.

  Further, the precharge circuit 4 can control the output voltages of the booster circuit 5 and the step-down circuit 6 in two stages. The step-up circuit 5 and the step-down circuit 6 can switch the output voltage for precharging the capacitor 9 in two stages, that is, a second charging voltage according to the output voltage of the battery 1 and a first charging voltage lower than the second charging voltage. It is said. Here, the first charging voltage is a voltage of 60 V or less, and may be 48 to 60 V, for example. Further, the second charging voltage is a voltage according to the output voltage of the battery 1 and can be set to 200 to 400 V, for example.

  The precharge circuit 4 starts precharging the capacitor 9 with the output voltage of the step-up circuit 5 or step-down circuit 6 as the first charge voltage. In this way, by suppressing the voltage at the start of precharging to a low level, it is possible to effectively prevent the output voltage of the precharge circuit 4 from rising immediately after the start of precharging and exceeding the allowable withstand voltage on the load side. Further, the precharge circuit 4 immediately stops precharging when an abnormality detection circuit 7 described later determines that there is an abnormality in the capacitor 9 or its connection circuit, for example, a serious abnormality such as an open failure or a short failure. At this time, since the precharge circuit 4 has a first charge voltage of 60 V or less, even if the precharge is interrupted due to abnormality detection, it is not classified as a high voltage, and therefore a circuit for forcibly discharging and its control can be omitted.

  Further, when the abnormality detection circuit 7 determines that the capacitor 9 or its connection circuit is normal, the precharge circuit 4 switches the output voltage to the second charging voltage and continues to precharge the capacitor 9. Thereby, the capacitor 9 can be quickly precharged to a predetermined voltage. Further, even when the abnormality detection circuit 7 determines that the capacitor 9 is deteriorated, the precharge can be continued without stopping the precharge depending on the degree of deterioration of the capacitor 9. For example, even when the capacitor is deteriorated and the function as a smoothing capacitor cannot be sufficiently satisfied, if the short-time use is possible, the precharge can be continued and the use can be permitted. Also in this case, the precharge is continued by switching the output voltage of the precharge circuit 4 to the second output voltage. As a result, when an abnormality is detected, an appropriate response can be made without prohibiting the traveling of the vehicle.

(Abnormality detection circuit 7)
The abnormality detection circuit 7 controls the on / off of the output switch 3 and detects the abnormality of the control circuit 16 that controls the operation state of the booster circuit and the step-down circuit of the precharge circuit 4 and the capacitor 9 or its connection circuit. A voltage detection circuit 14 for detecting the voltage of the capacitor 9 and a determination circuit 15 for determining abnormality from a signal input from the voltage detection circuit 14 are provided.

(Control circuit 16)
The control circuit 16 controls the output switch 3 and the precharge circuit 4 in response to an ON signal (for example, when the ignition switch is turned on) input from the main control circuit 27 on the load side to load the battery 1. 20 is connected. When the ON signal is input from the main control circuit 27, the control circuit 16 switches the booster circuit 5 and the step-down circuit 6 of the precharge circuit 4 to the ON state while keeping the output switch 3 OFF, and the capacitor 9 Start precharging. When the capacitor 9 is precharged, the control circuit 16 switches the step-up circuit 5 and the step-down circuit 6 of the precharge circuit 4 to the off state, and then switches the output switch 3 on to connect the battery 1 to the load 20. . Further, when an off signal (for example, a state in which the ignition switch is switched off) is input from the main control circuit 27, the abnormality detection circuit 7 switches the output switch 3 off and disconnects the battery 1 from the load 20. .

(Voltage detection circuit 14)
The voltage detection circuit 14 detects the voltage of the capacitor 9 when the precharge circuit 4 starts precharging the capacitor 9. The voltage detection circuit 14 detects the initial voltage V0 of the capacitor 9 when the capacitor 9 is precharged, that is, when the precharge of the capacitor 9 is started, and also calculates the capacitor voltage V of the capacitor 9 at a predetermined sampling period. To detect. The sampling period T of the voltage detection circuit 14 can be set to, for example, 10 msec in the power supply device in which the precharge circuit 4 finishes precharging the capacitor 9 in 100 msec to 600 msec.

(Determination circuit 15)
The determination circuit 15 detects an abnormality of the capacitor 9 or its connection circuit from the voltage rise characteristic of the capacitor 9 to be precharged. The determination circuit 15 calculates the voltage increase rate a of the capacitor 9 to be precharged, compares the calculated voltage increase rate a with a preset threshold value, and detects an abnormality in the capacitor 9 or its connection circuit. For example, as shown in FIG. 3, the determination circuit 15 detects a precharge time t required for the capacitor voltage V of the capacitor 9 to rise from a 0 V state to a predetermined first charging voltage Vr, The voltage increase rate a is calculated from the charging voltage Vr and the precharge time t. The voltage increase rate a is calculated by the following equation.
a = Vr / t

Here, the first charging voltage Vr is the first output voltage that becomes a low voltage when the booster circuit 5 or the step-down circuit 6 of the precharge circuit 4 can adjust the output voltage in two stages, or The voltage can be slightly lower than the output voltage. The precharge time t is calculated from the number of sampling times x until the voltage of the capacitor 9 rises from 0V to the first charge voltage Vr. That is, the precharge time t is calculated by the following equation.
(Precharge time t) = (sampling count x) × (sampling period T)

  As shown in FIG. 3, the determination circuit 15 determines the voltage increase rate from the precharge time t required for the capacitor voltage V of the capacitor 9 detected at a predetermined sampling period to increase from 0 V to the first charging voltage Vr. a is calculated, and further, it is determined whether or not the calculated voltage increase rate a is within a predetermined range, and an abnormality of the capacitor or its connection circuit is detected. In FIG. 3, since the horizontal axis is the precharge time t and the vertical axis is the capacitor voltage V, the voltage increase rate a calculated by Vr / t is 2 points (0, 0) and ( t, Vr) and is obtained as the slope of the straight line m. Further, in FIG. 3, in order to make the normal range of the voltage increase rate a easy to understand, a straight line n1 indicating the voltage increase rate b1 which is the upper limit of the normal range and a straight line indicating the voltage increase rate b2 which is the lower limit of the normal range. n2 is displayed.

  A curve C in FIG. 3 shows a voltage rise characteristic of the capacitor when the capacitor 9 and its connection circuit are in a normal state and the capacitor 9 is precharged. The determination circuit 15 determines that the capacitor 9 and its connection circuit are normal when the voltage increase rate a3 (a3 = Vr / t3) is within the normal range, as indicated by the curve C in FIG. That is, the determination circuit 15 determines that the capacitor 9 and its connection circuit are normal when b1 ≦ a3 ≦ b2.

  Further, a curve B in FIG. 3 shows an abnormal state of the capacitor 9, in particular, a state in which the electrostatic capacity is lowered due to the deterioration of the capacitor 9. In this state, since the capacity of the capacitor 9 is reduced, the precharge time t2 until the capacitor voltage rises from 0 V to the first charging voltage Vr when the capacitor 9 is precharged is compared with a normal state. Shorter. In this state, the capacitor 9 cannot fully satisfy the function as a smoothing capacitor, but it can be used for a short time. Therefore, as shown by the curve B, the determination circuit 15 has a voltage increase rate a2 (a2 = Vr / t2) higher than the voltage increase rate b1 that is the upper limit of the normal range, but is higher than the voltage increase rate b1. Further, when the state is equal to or lower than the maximum increase rate b3 (see the straight line n3 in FIG. 3) set higher, that is, when b1 <a2 ≦ b3, it is determined that the capacitor 9 is deteriorated (capacity decrease). However, in this state, it can be determined that the device is in a usable state conditionally. Therefore, the maximum rate of increase b3 is set to the maximum value that indicates the limit at which the capacitor can be used conditionally.

  A curve A in FIG. 3 indicates that the capacitor 9 or its connection circuit is in an abnormal state, particularly an open failure state. Here, the open failure in the capacitor 9 or its connection circuit means a state where the circuit is not normally connected due to disconnection or poor contact of the capacitor or its connection circuit, or a state where the connection resistance is abnormally large. In this state, when precharging of the capacitor 9 is started, the capacitor voltage V rises rapidly, and the precharge time t1 until the capacitor voltage rises from 0 V to the first charging voltage Vr becomes extremely short. Therefore, as shown by the curve A, the determination circuit 15 determines that the voltage increase rate a1 (a1 = Vr / t1) is higher than the voltage increase rate b1 that is the upper limit of the normal range (see FIG. 3 (see the straight line n3 in FIG. 3), that is, when b3 <a1, it is determined that the capacitor 9 or its connection circuit is an open failure.

  Further, a curve D in FIG. 3 shows an abnormal state of the capacitor 9, in particular, a state in which its internal resistance has increased due to deterioration of the capacitor 9. In this state, when the capacitor 9 is precharged, the precharge time t4 until the capacitor voltage rises from 0 V to the first charging voltage Vr is longer than in a normal state. In this state, the capacitor 9 cannot fully satisfy the function as a smoothing capacitor, but it can be used for a short time. Therefore, as shown by the curve D, the determination circuit 15 has a voltage increase rate a4 (a4 = Vr / t4) that is lower than the voltage increase rate b2 that is the lower limit of the normal range. Further, when the state is equal to or higher than the lowest increase rate b4 (see the straight line n4 in FIG. 3) set lower, that is, when b4 ≦ a4 <b2, it is determined that the capacitor 9 is deteriorated (internal resistance increase). However, in this state, it can be determined that the device is in a usable state conditionally. Therefore, the minimum rate of increase b4 is set to the lowest value that indicates the limit at which the capacitor can be used conditionally.

  Furthermore, a curve E in FIG. 3 shows a state in which the capacitor 9 or its connection circuit is abnormal, in particular, a short-circuit failure state. In this state, even if the precharge of the capacitor 9 is started, the capacitor voltage V does not increase, and the capacitor voltage becomes 0 V even after a predetermined precharge time t5 has elapsed. Therefore, the determination circuit 15 determines that the capacitor or the connection circuit is short-circuited if the voltage of the capacitor does not increase even after the predetermined precharge time t5 has elapsed.

(Memory 17)
The abnormality detection circuit 7 is a normal range of the voltage increase rate a for determining that the capacitor or its connection circuit is normal, or a limit value that can be used conditionally although the capacitor is deteriorated. A maximum increase rate b3 set higher than the upper limit voltage increase rate b1 and a minimum increase rate b4 set lower than the voltage increase rate b2 serving as the lower limit of the normal range are stored in the memory 17. The determination circuit 15 compares the calculated voltage increase rate a with these threshold values stored in the memory 17 to determine whether the capacitor 9 or its connection circuit is abnormal.

  In the state where the precharge circuit 4 precharges the capacitor 9 as described above, the power supply devices 100 and 200 determine the abnormality of the capacitor or its connection circuit from the voltage rise characteristics as shown in FIGS. Depending on the result, the precharge circuit 4 and the output switch 3 are controlled to connect the battery 1 to the load 20 or stop the precharge. 4 to 8 are timing charts showing ON / OFF states of the precharge circuit 4 and the output switch 3 controlled by the abnormality detection circuit 7, and changes in the voltage of the capacitor 9 precharged by the precharge circuit 4. FIG. The graph shown is shown.

(Condenser and its connection circuit are normal)
FIG. 4 shows a sequence in a normal state of the capacitor and its connection circuit. As shown in this figure, in the normal state of the capacitor and its connection circuit, when precharging is started with the precharge circuit 4 turned on, the capacitor 9 is precharged normally and the voltage increase rate a3 of the capacitor is normal. Within range. When it is determined that the capacitor and its connection circuit are normal, the abnormality detection circuit 7 controls the booster circuit 5 or the step-down circuit 6 of the precharge circuit 4 by the control circuit 16 to increase the precharge voltage and perform precharge. Continue. Here, when the booster circuit 5 or the step-down circuit 6 of the precharge circuit 4 can adjust the output voltage in two stages, the precharge voltage is raised to the second output voltage that becomes a high voltage.

  When the voltage of the capacitor 9 that is continuously precharged rises to the second charge voltage Vs, the abnormality detection circuit 7 controls the precharge circuit 4 to be turned off and ends the precharge. Here, the second charging voltage Vs can be the above-described second output voltage or a voltage slightly lower than the second output voltage. When the precharge is completed, the abnormality detection circuit 7 turns on the output switch 3 to connect the battery 1 to the load 20. When the output switch 3 is switched on, the capacitor voltage V rises to the output voltage Vb of the battery 1.

(Capacitor deteriorates and capacity decreases)
FIG. 5 shows a sequence in a state where the capacitor 9 is deteriorated and the capacity is reduced. As shown in this figure, in the state where the capacity of the capacitor is reduced, when the precharge circuit 4 is turned on and the precharge is started, the precharge time t2 becomes shorter than the normal state, and the voltage increase rate a2 is It becomes higher than the voltage increase rate b1 (see FIG. 3) which is the upper limit of the normal range. In this state, the capacitor 9 cannot fully satisfy the function as a smoothing capacitor, but it can be used for a short time. Therefore, in the determination circuit 15, the voltage increase rate a2 is higher than the voltage increase rate b1 that is the upper limit of the normal range, but is less than the maximum increase rate b3 (see FIG. 3) set higher than the voltage increase rate b1. In this state, it is determined that the capacitor 9 has deteriorated and the capacity has decreased, and this is transmitted to the main control circuit 27, but it is determined that the capacitor can be used for a short time, and Continue charging without stopping.

  The abnormality detection circuit 7 controls the booster circuit 5 or the step-down circuit 6 of the precharge circuit 4 by the control circuit 16 to raise the precharge voltage to the second output voltage and continue the precharge. When the voltage of the capacitor that is continuously precharged rises to the second charge voltage Vs, the abnormality detection circuit 7 controls the precharge circuit 4 to be turned off and ends the precharge. When the precharge is completed, the abnormality detection circuit 7 turns on the output switch 3 to connect the battery 1 to the load 20. When the output switch 3 is switched on, the capacitor voltage V rises to the output voltage Vb of the battery 1.

(The capacitor or its connection circuit is in an open failure state)
FIG. 6 shows a sequence in a state where the capacitor or its connection circuit is in an abnormal state and an open failure occurs. As shown in this figure, in a state where the capacitor or its connection circuit is in an open failure state, when precharging is started with the precharge circuit 4 turned on, the capacitor voltage V rapidly increases and the voltage increase rate a1 is normal. It becomes higher than the maximum increase rate b3 set higher than the voltage increase rate b1 which is the upper limit of the range. When the determination circuit 15 determines that the capacitor or its connection circuit has an open failure, the abnormality detection circuit 7 controls the precharge circuit 4 to be turned off to stop the precharge. Furthermore, the abnormality detection circuit 7 transmits to the main control circuit 27 that the capacitor or its connection circuit is an open failure, and warns this to the load side.

(Condenser deteriorates and internal resistance increases)
FIG. 7 shows a sequence in a state where the capacitor 9 is deteriorated and the internal resistance is increased. As shown in this figure, in the state where the internal resistance of the capacitor is increased, when the precharge circuit 4 is turned on and the precharge is started, the precharge time t4 becomes longer than the normal state, and the voltage increase rate a4 is The voltage increase rate b2 (see FIG. 3), which is the lower limit of the normal range, is lower. In this state, the capacitor 9 cannot fully satisfy the function as a smoothing capacitor, but it can be used for a short time. Accordingly, the determination circuit 15 has a voltage increase rate a4 that is lower than the voltage increase rate b2 that is the lower limit of the normal range, but is equal to or higher than the minimum increase rate b4 (see FIG. 3) set lower than the voltage increase rate b2. In this state, it is determined that the capacitor 9 is deteriorated and the internal resistance is increased, and this is transmitted to the main control circuit 27, but it is determined that the capacitor can be used for a short time. Continue precharging without stopping.

  The abnormality detection circuit 7 controls the booster circuit 5 or the step-down circuit 6 of the precharge circuit 4 by the control circuit 16 to raise the precharge voltage to the second output voltage and continue the precharge. When the voltage of the capacitor that is continuously precharged rises to the second charge voltage Vs, the abnormality detection circuit 7 controls the precharge circuit 4 to be turned off and ends the precharge. When the precharge is completed, the abnormality detection circuit 7 turns on the output switch 3 to connect the battery 1 to the load 20. When the output switch 3 is switched on, the capacitor voltage V rises to the output voltage Vb of the battery 1.

(Capacitor or its connection circuit is short circuit failure)
FIG. 8 shows a sequence in a state where the capacitor or its connection circuit is in an abnormal state and a short circuit failure occurs. As shown in this figure, when the capacitor or its connection circuit is in a short circuit failure state, the capacitor voltage V does not rise even if the precharge circuit 4 is turned on to start precharging. Therefore, if the capacitor voltage does not increase even after a predetermined precharge time t5 has elapsed after the start of precharging, the determination circuit 15 determines that the capacitor or the connection circuit is short-circuited. When the determination circuit 15 determines that the capacitor or the connection circuit thereof is a short circuit failure, the abnormality detection circuit 7 controls the precharge circuit 4 to be turned off to stop the precharge. Further, the abnormality detection circuit 7 transmits to the main control circuit 27 that the capacitor or its connection circuit has a short circuit failure, and warns this to the load side.

  As described above, the abnormality detection circuit 7 determines the abnormality of the capacitor or its connection circuit from the voltage rise characteristic of the capacitor 9 to be precharged. In the abnormality determination in FIGS. 3 to 8, the voltage increase rate a obtained by Vr / t is compared with the normal range (b1 to b2), the maximum increase rate b3, and the minimum increase rate b4 that are threshold values. Here, in the abnormality determination in FIGS. 3 to 8, the voltage increase rate a in a state where the voltage of the capacitor increases from 0 V to the first charging voltage Vr is used. In this case, Vr corresponding to the increased voltage of the capacitor. Is constant, the abnormality detection circuit can determine an abnormality simply by the magnitude of the precharge time t, not by the level of the voltage increase rate a obtained by Vr / t. In this determination, an abnormality is determined by comparing the magnitude of the precharge time t with a threshold value. However, since the capacitor rising voltage Vr is constant, the abnormality is substantially determined from the voltage rising characteristics of the capacitor. Equivalent.

  Similarly, a rise voltage with respect to a predetermined precharge time t can be detected, and an abnormality can be determined from the magnitude of the rise voltage. This determination is also abnormal by comparing the magnitude of the rising voltage with a threshold value, but since the precharge time t of the capacitor is constant, it is substantially the same value as the abnormality determination from the voltage increase characteristic of the capacitor. .

  Further, in the abnormality determination in FIGS. 3 to 8, the abnormality determination at the time of precharging when the capacitor is completely discharged at the start of precharging, that is, when the initial voltage of the capacitor at the start of precharging is 0V. Is shown. However, in the actual usage state of the power supply device, the capacitor on the load side is not necessarily completely discharged and the initial voltage is not in the state of 0 V at the start of precharging. In a state where the precharge of the capacitor is started, electric charge remains in the capacitor, and the initial voltage of the capacitor may not be 0V. In this case, since the voltage increase rate a changes depending on the initial voltage V0 of the capacitor, the determination circuit 15 needs to consider the initial voltage V0 of the capacitor at the start of precharging.

In such a case, when calculating the voltage increase rate a, the determination circuit 15 can determine the voltage increase of the capacitor as the difference between the first charging voltage Vr that is a predetermined voltage and the initial voltage V0. That is, the voltage increase rate a can be obtained by the following equation.
a = (Vr−V0) / t

  In addition, since the determination criterion for the voltage increase rate a is affected by the level of the initial voltage V0, the abnormality detection circuit 7 sets a threshold value that is a determination criterion for the voltage increase rate a with respect to the initial voltage V0 at the start of precharging in the memory 17. The abnormality can be determined based on this threshold value. Here, the threshold value that is a criterion for determining the voltage increase rate a with respect to the initial voltage V0 can be stored as a function of the voltage increase rate a with respect to the initial voltage V0, or the voltage increase rate a with respect to the initial voltage V0 can be stored as a table. . As described above, by storing the determination criterion of the voltage increase rate a corresponding to the initial voltage V0 at the start of precharge in the memory 17, more accurate abnormality determination can be realized.

  The above power supply apparatus is used as a power supply that is mounted on an electric vehicle such as a hybrid car or an electric vehicle and supplies electric power to a traveling motor, particularly as a power supply suitable for high power and large current applications. As a vehicle equipped with a power supply device, an electric vehicle such as a hybrid vehicle or a plug-in hybrid vehicle that runs with both an engine and a motor, or an electric vehicle that runs only with a motor can be used, and is used as a power source for these vehicles. .

(Power supply device for hybrid vehicles)
FIG. 9 shows an example in which a power supply device is mounted on a hybrid vehicle that runs with both an engine and a motor. A vehicle HV equipped with the power supply device shown in this figure includes an engine 24 for traveling the vehicle HV and a motor 22 for traveling, power supply devices 100 and 200 for supplying power to the motor 22, and batteries of the power supply devices 100 and 200. A generator 23 to be charged, a vehicle body 25 on which the engine 24, the motor 22, the power supply devices 100 and 200, and the generator 23 are mounted, and a wheel 26 that is driven by the engine 24 or the motor 22 to run the vehicle body 25. And. The power supply devices 100 and 200 are connected to the motor 22 and the generator 23 via the DC / AC inverter 21. The vehicle HV travels by both the motor 22 and the engine 24 while charging and discharging the batteries of the power supply devices 100 and 200. The motor 22 drives the vehicle HV by being driven in a region where engine efficiency is poor, for example, during acceleration or low-speed traveling. The motor 22 is driven by power supplied from the power supply devices 100 and 200. The generator 23 is driven by the engine 24 or is driven by regenerative braking when the vehicle is braked to charge the batteries of the power supply devices 100 and 200.

(Power supply for electric vehicles)
FIG. 10 shows an example in which a power supply device is mounted on an electric vehicle that runs only with a motor. A vehicle EV equipped with the power supply device shown in this figure charges a motor 22 for running the vehicle EV, power supply devices 100 and 200 for supplying electric power to the motor 22, and batteries of the power supply devices 100 and 200. A generator body 23, a motor 22, power supply devices 100 and 200, and a vehicle body 25 on which the generator 23 is mounted, and wheels 26 that are driven by the motor 22 and run the vehicle body 25. The power supply devices 100 and 200 are connected to the motor 22 and the generator 23 via the DC / AC inverter 21. The motor 22 is driven by power supplied from the power supply devices 100 and 200. The generator 23 is driven by energy when regeneratively braking the vehicle EV, and charges the batteries of the power supply devices 100 and 200.

  The power supply device of the present invention is a power supply device that supplies power from a battery to a load in which capacitors are connected in parallel, and can be suitably used for a power supply device that can reliably detect abnormality of the capacitor and its connection circuit. Such a power supply device can be suitably used as a power source for a motor that drives an electric vehicle such as a hybrid car, a plug-in hybrid car, or an electric vehicle.

  DESCRIPTION OF SYMBOLS 100, 200 ... Power supply device, 1 ... Battery, 2 ... Battery, 3 ... Output switch, 3A ... 1st output switch, 3B ... 2nd output switch, 4 ... Precharge circuit, 5 ... Boost circuit, 5A ... Boost converter, 6 ... Step-down circuit, 6A ... Step-down converter, 7 ... Abnormality detection circuit, 9 ... Capacitor, 10 ... Output terminal, 11 ... Sub-battery, 11A ... Lead battery, 14 ... Voltage detection circuit, 15 ... Determination circuit, 16 ... Control circuit , 17 ... Memory, 18 ... Protection element, 19 ... Current sensor, 20 ... Load, 21 ... DC / AC inverter, 22 ... Motor, 23 ... Generator, 24 ... Engine, 25 ... Vehicle body, 26 ... Wheel, 27 ... Main control circuit, HV ... vehicle, EV ... vehicle

Claims (13)

A battery for supplying power to a load having a capacitor connected in parallel to the input side;
An output switch electrically connected between the battery and the load;
A power supply device comprising a precharge circuit for precharging a capacitor of a load in an off state of the output switch,
The precharge circuit is
A sub-battery having a lower output voltage than the battery;
A booster circuit that boosts the output of the sub-battery to precharge the capacitor;
The power supply device further includes an abnormality detection circuit that determines an abnormality of the capacitor or a connection circuit thereof from a voltage rise characteristic of the capacitor precharged by the precharge circuit. The power supply device according to claim 1,
The power supply device in which the sub-battery is a 12V lead battery. A battery for supplying power to a load having a capacitor connected in parallel to the input side;
An output switch electrically connected between the battery and the load;
A power supply device comprising a precharge circuit for precharging a capacitor of a load in an off state of the output switch,
The precharge circuit includes a step-down circuit that steps down the output voltage of the battery and precharges a capacitor;
The power supply device further includes an abnormality detection circuit that determines an abnormality of the capacitor or a connection circuit thereof from a voltage rise characteristic of the capacitor precharged by the precharge circuit. The power supply device according to any one of claims 1 to 3,
The abnormality detection circuit calculates a voltage increase rate from the increased voltage and precharge time of the capacitor to be precharged, and when the voltage increase rate is within a predetermined normal range, the capacitor and its connection circuit are normal. A power supply device that determines that the precharge is continued. It is a power supply device described in Claim 4, Comprising:
When the voltage increase rate is higher than a maximum increase rate set higher than the upper limit of the normal range, the abnormality detection circuit determines that the capacitor or connection circuit is open and stops precharging. The power supply device according to claim 4 or 5, wherein
The abnormality detection circuit is a power supply device that determines that the capacitor is deteriorated when the voltage increase rate is higher than an upper limit of the normal range and not more than a maximum increase rate set higher than the upper limit of the normal range. The power supply device according to any one of claims 4 to 6,
The abnormality detection circuit is a power supply device that determines that the capacitor has deteriorated when the voltage increase rate is lower than a lower limit of the normal range and is equal to or higher than a minimum increase rate set lower than the lower limit of the normal range. The power supply device according to any one of claims 4 to 7,
The abnormality detection circuit is a power supply device that determines that a short circuit failure of the capacitor or the connection circuit and stops the precharge if the voltage of the capacitor does not increase even after a predetermined time has elapsed after starting the precharge. The power supply device according to any one of claims 1 to 8,
The precharge circuit is capable of controlling an output voltage for precharging a capacitor in two stages, a second output voltage according to the output voltage of the battery and a first output voltage lower than the second output voltage,
A power supply that starts precharging the capacitor at the first output voltage and switches the output voltage to the second output voltage to precharge the capacitor when the abnormality detection circuit determines that the capacitor and its connection circuit are normal. apparatus. The power supply device according to any one of claims 1 to 8,
The precharge circuit is capable of controlling an output voltage for precharging a capacitor in two stages, a second output voltage according to the output voltage of the battery and a first output voltage lower than the second output voltage,
When the precharge of the capacitor is started at the first output voltage, and the abnormality detection circuit determines that the capacitor has deteriorated, the precharge is continued by switching the output voltage to the second output voltage without stopping the precharge. A power supply that permits its use under certain conditions. The power supply device according to claim 9, wherein
The precharge circuit is
Stopping the precharging of the load capacitor when the abnormality detection circuit detects an abnormality in a state where the first output voltage is set to 60 V or less and precharging is performed with the first output voltage. A featured power supply. The power supply device according to any one of claims 1 to 11,
The power supply device is a power supply device mounted on an electric vehicle,
The load supplied with power from the battery is
A motor for driving the vehicle;
A DC / AC inverter for supplying electric power from the battery to the motor;
A power supply device in which a capacitor connected in parallel to the input side is a smoothing capacitor provided on the input side of the DC / AC inverter. An electric vehicle comprising the power supply device according to any one of claims 1 to 12,
An electric vehicle in which the power supply device supplies power to a motor that drives the vehicle.

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