JP2021106453A - Load circuit device and method for controlling the same - Google Patents

Abstract

To provide a load circuit device capable of increasing a voltage of a high-voltage battery, shortening a start-up time, and reducing deterioration in a relay, and a method for controlling the same.SOLUTION: A load circuit device 1 includes: a load device 3 for switching a connection state and a non-connection state with a drive battery 2 by main relays 4A, 4B to supply and not to supply electric power from a drive power source; a pre-charge circuit unit 5 connected to the drive battery and the load device and having a plurality of resistors r1, r2, r3; and a pre-charge control unit for changing a resistance value of one or a plurality of resistors of the pre-charge circuit unit according to a voltage value of the load device by first to third relays 5A to 5C. When the main relay switches the drive battery and the load circuit from the connection state to the non-connection state, the pre-charge control unit changes the resistance value of the pre-charge circuit unit stepwise according to the voltage value of the load unit.SELECTED DRAWING: Figure 2

Description

The present invention relates to a load circuit device and a method for controlling the load circuit device.

As an example of a load circuit device, there is a driving force control device for an electric vehicle that connects a high-voltage power supply to an electric power train that is a high-voltage device.

In the above control device, it is necessary to supply electric power from the high-voltage power source to the high-voltage device when the vehicle is started. When the vehicle is started, the voltage difference between the high-voltage power supply and the high-voltage device is large, so there is a risk that the rush current will flow and the main contactor will be welded.

Therefore, in the technique described in Patent Document 1, when the vehicle is started, a precharge resistor is used to set the voltage of the high-voltage device on the load side to the same level as the high-voltage battery on the drive side, and when the main relay is turned on. The rush current is reduced.

However, the voltage of the high-voltage battery tends to increase, and the precharge time becomes long.

That is, the high-voltage battery of the driving force control device for an electric vehicle tends to have a higher voltage, and it can be assumed that the higher the voltage, the longer the precharge time. In particular, when the voltage difference between the high-voltage battery and the high-voltage device becomes small after the vehicle is started, the amount of current from the high-voltage battery to the high-voltage device decreases, so it takes time to complete charging. ..

Since the precharge time is about three times as long as the battery voltage of about 300 V with the battery voltage of 1000 V, about 1 s of time is required. When the vehicle is started, the user may want to finish the vehicle start immediately, and the start time is an important factor for the user.

Patent Document 2 describes a technique using a plurality of precharge resistors. According to the technique described in Patent Document 2, the resistance of the precharge resistor is set to high resistance immediately after the start-up, and the amount of current is reduced. Then, as the voltage difference between the high-voltage battery and the high-voltage debas becomes smaller, the medium resistance is switched to the low resistance to suppress the rush current and shorten the precharge time.

Japanese Unexamined Patent Publication No. 2008-22675 Japanese Unexamined Patent Publication No. 2017-184333

However, in the technique described in Patent Document 2, even if the voltage of the high-voltage device is high immediately after startup, the resistance of the precharge resistor is set to high resistance, and the resistance is sequentially switched from medium resistance to low resistance. There is. For this reason, it takes time to precharge, and it is difficult to meet the demand for further increasing the voltage of the high-voltage battery and shortening the vehicle start-up time.

In addition, it is necessary to turn on the high resistance relay, then turn on the medium resistance relay, and then turn on the low resistance relay, which requires complicated operation of the relay during precharging. be. Therefore, relay welding and deterioration may proceed.

This hinders the reduction of welding and deterioration of the relay, and also hinders the reduction of the occurrence rate of damage to the resistor and the relay.

The present invention has been made in view of the above problems, and an object of the present invention is a load circuit device and a load circuit device capable of increasing the voltage of a high-voltage battery, shortening the start-up time, and reducing deterioration of relays and the like. Is to realize the control method of.

In order to achieve the above object, the present invention is configured as follows.

In the load circuit device, the main relay switches between the connected state and the disconnected state of the drive power supply, and the load unit in which power is supplied and not supplied from the drive power supply, and the drive power supply and the load unit. A precharge circuit unit connected to and having a plurality of resistors, and a precharge control unit that changes the resistance value of one or more of the plurality of resistors of the precharge circuit unit according to the voltage value of the load unit. To be equipped. When the drive power supply and the load unit are switched from the connected state to the non-connected state by the main relay, the precharge control unit has the precharge circuit unit according to the voltage value of the load unit. The resistance value of the above is changed stepwise.

Further, it is a control method of a load circuit device in which power is supplied and not supplied from the drive power supply by switching between a connected state and a non-connected state with the drive power supply by a main relay, wherein the drive power supply and the load are supplied. When the unit is switched from the connected state to the non-connected state, the connection state of the drive power supply and a plurality of resistors connected to the load unit is switched according to the voltage value of the load unit, and the drive power supply and the plurality of resistors connected to the load unit are switched. The resistance value between the power supply and the load unit is changed stepwise.

According to the present invention, it is possible to realize a load circuit device and a control method for the load circuit device, which can increase the voltage of the high-voltage battery, shorten the start-up time, and reduce the deterioration of relays and the like.

It is an overall schematic block diagram of Example 1 of this invention. It is an internal circuit diagram of the precharge circuit part in Example 1. FIG. It is a flowchart explaining the operation of the precharge circuit part controlled by the precharge control part. It is explanatory drawing of the open / closed state (connection state) of the 1st relay, the 2nd relay and the 3rd relay in the precharge control. It is an operation explanatory drawing of Example 1 of this invention. It is explanatory drawing that it is determined so that the voltage value becomes higher than the voltage threshold value which becomes less than an allowable current value. It is an internal circuit diagram of the precharge circuit part in Example 2 of this invention. It is a flowchart explaining the operation of the precharge circuit part in Example 2 of this invention.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, in all the drawings for explaining the embodiment, in principle, the same members are designated by the same reference numerals, and duplicate description will be omitted as appropriate.

The examples described below are examples in which the load circuit device and the control method of the load circuit device of the present invention are applied to the driving force control device and the driving force control method of the electric vehicle, but the present invention is limited to this. It is not applicable to other load circuit devices and control methods for load circuit devices.

(Example 1)
FIG. 1 is an overall schematic configuration diagram of a first embodiment of the present invention.

In FIG. 1, the driving force control device (load circuit control device) 1 of an electric vehicle is a drive battery (drive power supply) 2 which is a high-voltage battery, and a load device (load) to which electric power is supplied from the drive battery 2. The positive side main relay 4A and the negative side main relay 4B connected between the unit (inverter) 3, the drive battery 2 and the load device 3, and the current supplied from the drive battery 2 to the load device 3 It includes a precharge circuit unit 5 for control, a voltage measuring device 9 for measuring the voltage of the load device 3, and a precharge control unit 10.

The load device 3 (load unit) is switched between a connected state and a disconnected state with the drive battery 2 (drive power supply) by the main relays 4A and 4B, and power is supplied and not supplied from the drive battery 2. It is said.

The precharge circuit unit 5 is connected to the drive battery 2 and the load device 3, has a plurality of resistors, and has a value.

The precharge control unit 10 changes the resistance value of the precharge circuit unit 5 according to the voltage value of the load device 3. Then, when the drive battery 2 and the load device 3 are switched from the connected state to the non-connected state by the main relays 4A and 4B, the precharge control unit 10 performs a precharge circuit according to the voltage value of the load device 3. The resistance value of the part 5 is changed stepwise.
The load device 3 is connected to the electric motor 7.

The vehicle control unit 6 that controls the electric vehicle controls the opening / closing operation of the main relays 4A and 4B. Further, the vehicle control unit 6 issues an opening / closing operation command to the main relays 4A and 4B, and transmits the opening / closing operation command to the precharge control unit 10.

FIG. 2 is an internal circuit diagram of the precharge circuit unit 5 in the first embodiment. In FIG. 2, the voltage measuring instrument 9 shown in FIG. 1 is not shown.

In FIG. 2, the precharge circuit unit 5 has a first relay 5A and a resistor r1 connected in series with each other, and these first relay 5A and the first resistor r1 are connected to the drive battery 2 and the load device 3. Will be done.

Further, the second relay 5B and the second resistor r2, which are connected in series with each other, are connected in parallel with the first resistor r1. A terminal different from the terminal connected to the second resistor r2 of the second relay 5B is connected to the connection point between the first relay 5A and the first resistor r1.

Further, the third relay 5C and the third resistor r3, which are connected in series with each other, are connected in parallel with the second resistor r2. A terminal different from the terminal connected to the third resistor r3 of the third relay 5C is connected to the connection point between the second relay 5B and the second resistor r2.

The connection state of the first resistor r1, the second resistor r2, and the third resistor r3 is switched by the first relay 5A, the second relay 5B, and the third relay 5C.

The resistance values of the first resistor r1, the second resistor r2, and the third resistor r3 are substantially the same in the illustrated example.

When the first relay 5A is closed and the second relay 5B and the third relay 5C are open, the resistance value between the drive battery 2 and the load device 3 is maximized (high resistance (low voltage pattern)).

When the first relay 5A and the second relay 5B are closed and the third relay 5C is open, the resistance value between the drive battery 2 and the load device 3 is an intermediate value (medium resistance (medium voltage pattern)). ..

When the first relay 5A, the second relay 5B, and the third relay are closed, the resistance value between the drive battery 2 and the load device 3 becomes the lowest (low resistance (high voltage pattern)).

The resistance values of the first resistor r1, the second resistor r2, and the third resistor r3 can be set to appropriate values from the device conditions such as the voltage value of the drive battery 2.

FIG. 3 is a flowchart illustrating the operation of the precharge circuit unit 5 controlled by the precharge control unit 10. However, the operation control of the precharge circuit unit 5 can be configured to be performed by the vehicle control unit 6 instead of the precharge control unit 10.

In step S1 of FIG. 3, if the main relays 4A and 4B are closed and in a conductive state, and the precharge operation for adjusting the voltage difference between the drive battery 2 and the load device 3 is in progress, the process proceeds to step S2. .. Then, in step S2, the precharge circuit unit 5 turns on the first relay 5A, proceeds to step S3, and performs precharge control described later.

In step S1, if the main relays 4A and 4B are open and the conduction state is cut off and the precharge operation is not in progress, the process proceeds to step S4 and the first relay 5A is turned off. Then, in step S5, it is determined whether or not the voltage value (load side voltage) measured by the voltage measuring instrument 9 is larger than the voltage threshold value A.

In step S5, when the load side voltage is larger than the voltage threshold value A, the process proceeds to step S9, and the open / closed state of the first relay 5A, the second relay 5B, and the third relay 5C is changed so as to obtain the high voltage pattern described above. Set.

If the voltage value (load side voltage) measured by the voltage measuring instrument 9 in step S5 is equal to or less than the voltage threshold value A, the process proceeds to step S6. Then, in step S6, it is determined whether or not the voltage value (load side voltage) measured by the voltage measuring instrument 9 is larger than the voltage threshold value B. The voltage threshold B is smaller than the voltage threshold A.

When the load-side voltage is larger than the voltage threshold value B, the process proceeds to step S7, and the open / closed states of the first relay 5A, the second relay 5B, and the third relay 5C are set so as to have the above-mentioned medium voltage pattern.

If the voltage value (load side voltage) measured by the voltage measuring instrument 9 in step S6 is equal to or less than the voltage threshold B, the process proceeds to step S8, and the first relay 5A and the second relay are arranged so as to have the above-mentioned low voltage pattern. The open / closed state of 5B and the third relay 5C is set.

As described above, the resistance value of the precharge circuit unit 5 is changed stepwise.

Next, the above-mentioned precharge control will be described with reference to FIG. FIG. 4 is an explanatory diagram of an open / closed state (connection state) of the first relay 5A, the second relay 5B, and the third relay 5C in the precharge control.

In FIG. 4, when the load side voltage is high voltage, a high voltage pattern (connection state shown in the upper part of FIG. 4) is selected, the first relay 5A is set to the open state, and the second relay 5B and the third relay 5B The relay 5C is set to the closed state. Then, when the precharge is started, the first relay 5A is set to the closed state, all of the first relay 5A, the second relay 5B and the third relay 5C are set to the closed state, and the connection state is changed. .. Due to this high voltage pattern, the resistance between the drive battery 2 and the load device 3 is set to the smallest value.

Further, in FIG. 4, when the load side voltage is medium voltage, the medium voltage pattern (connection state shown in the middle stage of FIG. 4) is selected, the first relay 5A is set to the open state, and the second relay 5B is set. The closed state is set, and the third relay 5C is set to the open state. Then, when the precharge is started, the first relay 5A is set to the closed state, the second relay 5B is set to the closed state, and the third relay 5C is set to the open state. Due to this medium voltage pattern, the resistance between the drive battery 2 and the load device 3 is set to an intermediate value.

Then, when the load side voltage becomes high, the third relay 5C is set to the closed state, all of the first relay 5A, the second relay 5B, and the third relay 5C are set to the closed state, and the connection state is changed. NS.

Further, in FIG. 4, when the load side voltage is low, the low voltage pattern (connection state shown in the lower part of FIG. 4) is selected, and all of the first relay 5A, the second relay 5B, and the third relay 5C are selected. Is set to the open state. Then, when the precharge is started, the first relay 5A is set to the closed state, and the second relay 5B and the third relay 5C are set to the open state. Due to this low voltage pattern, the resistance between the drive battery 2 and the load device 3 is set to the maximum value.

Then, when the load side voltage becomes a medium voltage, the third relay 5C is set to the open state, and the first relay 5A and the second relay 5B are set to the closed state.

Subsequently, when the load side voltage becomes high, the third relay 5C is set to the closed state, the first relay 5A, the second relay 5B, and the third relay 5C are all set to the closed state, and the connection state is changed. Will be done.

FIG. 5 is an operation explanatory view of the first embodiment of the present invention, in which the key switch is turned off and the key switch is turned on (returned) again from the time when the key switch (not shown) is turned on. It is a current waveform diagram of time.

In FIG. 5, when the key switch is turned on at the time point t1, the precharge is started at the time point t2. When the precharge is started, the main relays 4A and A4B are turned on (conducted) at the time point t3 when the charge current flows.

Then, when the key switch is turned off at the time point t4, the main relays 4A and A4B are turned off at the time point t5 (the state is cut off).

Next, assuming that the key switch is turned on again at the time point t6 and the load device 3 is in a high voltage state at this time point t6, in the first embodiment of the present invention, the setting state on the left side of the upper part of FIG. It has become. That is, the relay 5A is in the off state, and the relay 5B and the relay 5C are in the on state. Therefore, at the time t6 when the key switch is turned on again, the precharge can be started from the state of low resistance only by turning on the relay 5A.

On the other hand, when the precharge control as in the first embodiment of the present invention is not performed, even when the key switch is turned on again and the load device 3 is in a high voltage state. , Precharge is performed from the state of high resistance. Therefore, the precharge current starts to flow from a small value, and the charge completion time is delayed as compared with the first embodiment of the present invention.

When the load device 3 is in the medium voltage state at the time point t6, in the first embodiment of the present invention, it is in the setting state on the left side of the middle stage of FIG. That is, the relays 5A and 5C are in the off state, and the relay 5B is in the on state. Therefore, at t6 when the key switch is turned on again, the relay 5A is turned on and precharging is started from the state of medium resistance. Then, when the load device 3 is in a high voltage state, the relay 5C is turned on and the load device 3 is in a low resistance state.

If the load device 3 is in the medium voltage state at the time point t6, precharging is started from the medium resistance state.

On the other hand, when the precharge control is not performed, the precharge is performed from the high resistance state even when the key switch is turned on again and the load device 3 is in the medium voltage state. Will be done. Therefore, the precharge current starts to flow from a small value, and the charge completion time is delayed as compared with the first embodiment of the present invention.

Further, in the first embodiment of the present invention, since the relays 5B and 5C are in the connected state before being energized in the high voltage state, the switch-off operation of the relays 5B and 5C is unnecessary during the precharge period. Yes, there is no occurrence of arcs. Therefore, deterioration of the relays 5B and 5C can be suppressed, the risk of welding can be reduced, safety can be improved, and the service life can be extended.

Further, in the medium voltage state, since the relay 5B is in the connected state before being energized, the relay 5B switch-off operation is unnecessary during the precharge period, and no arc or the like is generated. Therefore, deterioration of the relay 5B can be suppressed, the risk of welding can be reduced, safety can be improved, and the service life can be extended.

Next, in Example 1 of the present invention, determination of the resistance value (high resistance value, medium resistance value, low resistance value) of the precharge circuit unit 5 will be described.

The resistance value of the precharge circuit unit 5 is higher than the voltage threshold of the load device 3 in which the current flowing when the drive battery 2 and the load device 3 are connected is equal to or less than the allowable current value (rated current of the resistor). It is determined to be a voltage value. The voltage threshold value is a value calculated from an allowable current and a resistance value.

FIG. 6 is an explanatory diagram showing that the voltage value is determined to be higher than the voltage threshold value which is equal to or less than the allowable current value.

In FIG. 6, assuming that the low voltage threshold value is v1, the resistance value is determined by the voltage value v10 which is a constant voltage higher than the low voltage threshold value v1. In this case, the resistance value is high, which is the resistance value of the resistor r1.

Assuming that the medium voltage threshold value is v2, the resistance value is determined by the voltage value v20, which is a constant voltage higher than the medium voltage threshold value v2. In this case, the resistance value is a medium level, and the resistance value is such that the first resistor r1 and the second resistor r2 are connected in parallel.

Assuming that the high voltage threshold value is v3, the resistance value is determined by the voltage value v30, which is a constant voltage higher than the high voltage threshold value v3. In this case, the resistance value is a low level, and the resistance value is such that the first resistor r1, the second resistor r2, and the third resistor r3 are connected in parallel.

That is, each of the resistance values of the plurality of resistors (first resistor r1, second resistor r2, third resistor r3) is the permissible current of the plurality of resistors (first resistor r1, second resistor r2, third resistor r3). It is determined based on a voltage value that is constant voltage higher than the voltage threshold so as to be as follows.

When switching the resistance value, it is necessary to select the resistance value so that it is within the range of the current allowable value, which is determined so that the voltage value is higher than the voltage threshold value that is equal to or less than the allowable current value. This is because the precharge circuit unit 5 is not connected to the drive battery 2 and the load device 3 before the key switch is re-turned on and the re-precharge is started, so that the voltage threshold is shifted to the safe side.

How much the voltage value should be shifted to the safe side can be set according to the characteristics of each device and the like.

The voltage threshold is calculated from, for example, the accuracy of the resistance values of the first resistor r1, the second resistor r2, and the third resistor r3, which are resistors, and the accuracy of the voltage sensing of the voltage measuring instrument 9. This is because if the accuracy of the resistance value of the resistor and the accuracy of the voltage sensing are low, it may not be possible to select a suitable resistor (resistor).

The voltage threshold value is calculated by the following equation (1).
Voltage threshold = (power supply voltage-resistor current allowable value x resistance correction value) x load side voltage correction value ... (1)

In the above equation (1), the load-side voltage correction value is an absolute value of the value obtained by dividing the accuracy of the voltage sensing of the voltage measuring instrument 9 by 100.

Further, in the above equation (1), the resistance correction value is represented by the following equation (2).
Resistance correction value = Resistance value-Resistance value x │ Resistor accuracy / 100 │ ・ ・ ・ (2)

The accuracy of the resistance value of the resistor is ± 5% to ± 10%, and the accuracy of voltage sensing is several percent (voltage conversion error due to the sensing resistor).

As described above, according to the first embodiment of the present invention, according to the voltage level on the load device 3 side after the main relay is turned off (corresponding to the voltage threshold corresponding to the voltage value of the load device 3 which is the load unit). (And therefore), select the optimum pattern from the high voltage pattern, medium voltage pattern, and low voltage pattern, and set the resistance value between the drive battery 2 and the load device 3 to the second relay 5B and the third. It is set according to the open / closed state of the relay 5C. Then, when the key switch is turned on and turned on again, the resistance value between the drive battery 2 and the load device 3 is set in the optimum pattern in that state.

Therefore, it is possible to realize a load circuit device and a control method of the load circuit device that can increase the voltage of the high-voltage battery, shorten the start-up time, and reduce the deterioration of the relay and the like.

(Example 2)
Next, Example 2 of the present invention will be described.

FIG. 7 is an internal circuit diagram of the precharge circuit unit 8 according to the second embodiment of the present invention. Since the overall schematic configuration of Example 2 of the present invention is the same as the configuration shown in FIG. 1, illustration and detailed description thereof will be omitted. However, in the second embodiment, the precharge circuit unit 5 in FIG. 1 is replaced with the precharge circuit unit 8.

In FIG. 7, the illustration of the voltage measuring instrument 9 shown in FIG. 1 is omitted.

In FIG. 7, the precharge circuit unit 8 includes a fourth relay 8A, a fifth relay 8B, a sixth relay 8C, a fourth resistor r4, and a fifth resistor r5. The resistance value of the fourth resistor r4 is larger than the resistance value of the fifth resistor r5.

One end of the fourth relay 8A is connected to the positive terminal of the drive battery 2, and the other end is connected to the positive terminal of the load device 3 via the fourth resistor r4 and the sixth relay 8C. One end of the sixth relay is connected to the fourth resistor r4, and the other end is connected to the positive terminal of the load device 3.

Further, a connection point between the other end of the 4th relay 8A and the 4th resistance r4 and a connection point between the 4th resistance r4 and one end of the 6th relay are connected to the 5th relay 8B. The fifth relay 8B can switch between connecting to the connection point between the other end of the fourth relay 8A and the fourth resistance r4 or connecting to the connection point between the fourth resistance r4 and one end of the sixth relay. .. Further, the fifth relay 8B is a connection point between the other end of the fourth relay 8A and the fourth resistance r4 (connection point on the fourth relay 8A side) and a connection point between the fourth resistance r4 and one end of the sixth relay (the first). It is possible to switch to a neutral position that is not connected to any of the 6 relays (8C side connection points).

Further, the fifth relay 8B is connected to the positive terminal of the load device 3 via the fifth resistor r5. The operation of the precharge circuit unit 8 is performed by the precharge control unit 10. However, it is also possible to configure the vehicle control unit 6 to perform the operation of the precharge circuit unit 8.

The connection state between the fourth resistance r4 and the fifth resistance r5 is switched by the fourth relay 8A, the fifth relay 8B, and the sixth relay 8C.

In the precharge circuit unit 5 of the first embodiment, three resistors (r1, r2, r3) and three relays (first relay 5A, second relay 5B, third relay 5C) are used to obtain a high voltage pattern. Precharge control is performed using three patterns, a medium voltage pattern and a low voltage pattern.

In the precharge circuit unit 8 of the second embodiment, two resistors (r4, r5) and three relays (fourth relay 8A, fifth relay 8B, sixth relay 8C) are used to obtain a high voltage pattern, first. Precharge control is performed using four patterns of a medium voltage pattern, a second medium voltage pattern, and a low voltage pattern.

FIG. 8 is a flowchart illustrating the operation of the precharge circuit unit 8.

In step S1 of FIG. 8, if the main relays 4A and 4B are closed and in a conductive state, and the precharge operation for adjusting the voltage difference between the drive battery 2 and the load device 3 is in progress, the process proceeds to step S2A. .. Then, in step S2A, the precharge circuit unit 8 turns on the fourth relay 8A, proceeds to step S3A, and performs precharge control.

In step S1, if the main relays 4A and 4B are open and the conduction state is cut off and the precharge operation is not in progress, the process proceeds to step S4A and the fourth relay 8A is turned off. Then, in step S5A, it is determined whether or not the voltage value (load side voltage) measured by the voltage measuring instrument 9 is larger than the voltage threshold value A2.

In step S5A, when the load side voltage is larger than the voltage threshold value A2, the process proceeds to step S9A, and the open / closed state of the fifth relay 8B and the sixth relay 8C is set so as to have a high voltage pattern.

In the high voltage pattern, the 5th relay 8B is switched to the 4th relay side connection point, and the 6th relay 8C is set to the ON state. In the high voltage pattern, the fourth resistor r4 and the fifth resistor r5 are in parallel with each other, and the resistance between the drive battery 2 and the load device 3 has a low resistance value.

If the voltage value (load side voltage) measured by the voltage measuring instrument 9 in step S5A is equal to or less than the voltage threshold value A2, the process proceeds to step S6A. Then, in step S6A, it is determined whether or not the voltage value (load side voltage) measured by the voltage measuring instrument 9 is larger than the voltage threshold value B2. The voltage threshold value B2 is smaller than the voltage threshold value A2.

When the load-side voltage is larger than the voltage threshold value B2, the process proceeds to step S7A, and the open / closed states of the fifth relay 8B and the sixth relay 8C are set so as to have the first medium voltage pattern.

In the first medium voltage pattern, the fifth relay 8B is switched to the fourth relay side connection point, and the sixth relay 8C is set to the off state. In the first medium voltage pattern, the resistance between the drive battery 2 and the load device 3 is the resistance r5, which is the first medium resistance value larger than the low resistance value.

In step S6A, if the voltage value (load side voltage) measured by the voltage measuring device 9 is equal to or less than the voltage threshold B2, the process proceeds to step S8A, and the voltage value (load side voltage) measured by the voltage measuring device 9 is the voltage threshold C2. Determine if it is larger. The voltage threshold C2 is smaller than the voltage threshold B2.

In step S8A, when the load side voltage is larger than the voltage threshold value C2, the process proceeds to step S10A, and the open / closed state of the fifth relay 8B and the sixth relay 8C is set so as to have the second medium voltage pattern.

In the second medium voltage pattern, the fifth relay 8B is switched to the neutral position and the sixth relay 8C is set to the on state. In the second medium voltage pattern, the resistance between the drive battery 2 and the load device 3 is the fourth resistance r4, which is the second medium resistance value larger than the first medium resistance value.

If the voltage value (load side voltage) measured by the voltage measuring instrument 9 in step S8A is equal to or less than the voltage threshold value C2, the process proceeds to step 11A. In step S11A, the open / closed states of the 5th relay 8B and the 6th relay 8C are set so as to have a low voltage pattern.

In the low voltage pattern, the 5th relay 8B is switched to the 6th relay 8C side connection point side, and the 6th relay 8C is set to the off state. In the low voltage pattern, the resistance between the drive battery 2 and the load device 3 is a series connection of the fourth resistor r4 and the fifth resistor r5, and has a high resistance value larger than the second medium resistance value.

As described above, the resistance value of the precharge circuit unit 8 is changed stepwise.

Following steps S9A, S7A, S10A, and S11A, when precharging is started, the fourth relay 4 is turned on and precharging control is performed.

That is, in the case of the high voltage pattern of step S9A, when the fourth relay 8A is turned on, precharging is performed in the connected state.

In the case of the first medium voltage pattern in step S7A, when the fourth relay 8A is turned on, the first medium voltage pattern is changed to the high voltage pattern according to the voltage state, and precharging is performed.

In the case of the second medium voltage pattern in step S10A, when the fourth relay 8A is turned on, the transition from the second medium voltage pattern to the high voltage pattern via the first medium voltage pattern is performed according to the voltage state, and the pre-voltage pattern is selected. The charge is done.

In the low voltage pattern of step S11A, when the fourth relay 8A is turned on, the low voltage pattern transitions from the low voltage pattern to the high voltage pattern via the second medium voltage pattern and the first medium voltage pattern according to the voltage state. , Precharge is done.

According to the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained, the number of resistors used is smaller than that of the first embodiment, and the high voltage pattern and the first medium voltage are used. Precharge control can be performed by switching between a pattern, a second medium voltage pattern, and a low voltage pattern in four stages. As a result, the vehicle can be started earlier according to the voltage values of the drive battery 2 and the load device 3.

In Example 2, the voltage threshold value can be determined based on the same principle as in Example 1.

Further, in Examples 1 and 2, the ratio of the plurality of resistance values due to the plurality of resistors (r1, r2, r3) to each other and the ratio of the plurality of resistance values due to the resistors (r4, r5) to each other are doubled. It can be any of ~ 5 times.

Further, in the above-mentioned example, the stepwise change of the resistance value depending on the connection state of the plurality of resistors (r1 to r5) was performed using the relays 5A to 5C and 8A to 8C, but the relays are not limited to the relays. It can also be performed with a switch (switching device, for example, a transistor).

1 ... Load circuit device, 2 ... Drive battery, 3 ... Load device, 4A, 4B ... Main relay, 5, 8 ... Precharge circuit unit, 5A ... 1st relay , 5B ... 2nd relay, 5C ... 3rd relay, 6 ... Vehicle control unit, 7 ... Electric motor, 8A ... 4th relay, 8B ... 5th relay, 8C ... 6th relay, 9 ... Voltage measuring instrument, 10 ... Precharge control unit, r1, r2, r3, r4, r5 ... Resistance

Claims (12)

The load unit, which is switched between the connected state and the disconnected state with the drive power supply by the main relay, and the power is supplied and not supplied from the drive power supply.
A precharge circuit unit connected to the drive power supply and the load unit and having a plurality of resistors,
A precharge control unit that changes the resistance value of one or more of the plurality of resistors in the precharge circuit unit according to the voltage value of the load unit.
With
When the drive power supply and the load unit are switched from the connected state to the non-connected state by the main relay, the precharge control unit has the precharge circuit unit according to the voltage value of the load unit. A load circuit device characterized in that the resistance value of the above is changed stepwise. In the load circuit device according to claim 1,
The precharge control unit changes the resistance value stepwise according to the voltage threshold corresponding to the voltage value of the load unit among the plurality of voltage thresholds, and each of the resistance values due to the plurality of resistors is the plurality. A load circuit device, characterized in that it is determined based on a voltage value that is constant voltage higher than each of the plurality of voltage thresholds so as to be equal to or less than the permissible current of the resistance of. In the load circuit device according to claim 2,
A load circuit device, wherein each of the plurality of voltage threshold values is calculated from the accuracy of the plurality of resistors and the accuracy of voltage sensing of the load unit. In the load circuit device according to claim 2,
A load circuit device, characterized in that the ratio of the resistance values of the plurality of resistors to each other is set to be one of a ratio of 2 times to 5 times. In the load circuit device according to claim 1,
The precharge circuit unit includes a first resistor, a second resistor, a third resistor, and a switch that switches the connection state of the first resistor, the second resistor, and the third resistor. Whether the first resistor, the second resistor and the third resistor are connected in parallel, the first resistor and the second resistor are connected in parallel, or only the first resistor is connected. A load circuit device characterized in that the resistance value of the precharge circuit unit is changed stepwise by switching between the states and the state. In the load circuit device according to claim 1,
The precharge circuit unit includes a fourth resistor, a fifth resistor having a resistance value smaller than that of the fourth resistor, and a switch for switching the connection state of the fourth resistor and the fifth resistor. Whether the fourth resistor and the fifth resistor are connected in parallel to each other, only the fifth resistor is connected, or only the fourth resistor is connected, or the first. A load circuit device characterized in that the resistance value of the precharge circuit unit is changed stepwise by switching whether the four resistors and the fifth resistor are connected in series with each other. It is a control method of a load circuit device that switches between a connected state and a non-connected state with a drive power supply by a main relay, and supplies and does not supply power from the drive power supply.
When the drive power supply and the load unit are switched from the connected state to the non-connected state, the drive power supply and a plurality of resistors connected to the load unit are connected according to the voltage value of the load unit. Switch states,
A method for controlling a load circuit device, characterized in that the resistance value between the drive power supply and the load unit is changed stepwise. In the control method of the load circuit device according to claim 7,
The resistance value is changed stepwise according to the voltage threshold corresponding to the voltage value of the load unit among the plurality of voltage thresholds, and each of the resistance values due to the plurality of resistors is equal to or less than the allowable current of the plurality of resistors. A method for controlling a load circuit device, which is determined based on a voltage value higher than each of the plurality of voltage thresholds by a constant voltage. In the method for controlling a load circuit device according to claim 8,
A method for controlling a load circuit device, wherein each of the plurality of voltage threshold values is calculated from the accuracy of the plurality of resistors and the accuracy of voltage sensing of the load unit. In the method for controlling a load circuit device according to claim 8,
A method for controlling a load circuit device, characterized in that the ratio of the resistance values of the plurality of resistors to each other is set to be one of a ratio of 2 times to 5 times. In the control method of the load circuit device according to claim 7,
The plurality of resistors are a first resistor, a second resistor, and a third resistor, and the first resistor, the second resistor, and the third resistor are connected in parallel, or the first resistor and the third resistor are connected. Switching between a state in which the second resistor is connected in parallel and a state in which only the first resistor is connected, and the resistance value between the drive power supply and the load unit is changed stepwise. A characteristic load circuit device control method. In the control method of the load circuit device according to claim 7,
The plurality of resistors are a fourth resistor and a fifth resistor having a resistance value smaller than that of the fourth resistor, and the fourth resistor and the fifth resistor are connected to each other in parallel, or only the fifth resistor. Is connected, only the fourth resistor is connected, or the fourth resistor and the fifth resistor are connected in series with each other. A method for controlling a load circuit device, characterized in that the resistance value between the load unit and the load unit is changed stepwise.

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