Power control device and power control method

Abstract

To provide a power supply control unit and a power supply control method that can prevent a reduction in the durability of an inter-system switch.SOLUTION: A power supply control unit 1 comprises: a first system 110; a second system 120; an inter-system switch 41; a primary ground fault detection unit 31; a secondary ground fault detection unit 32; and a mask processing unit 33. The first system supplies power of a first power supply 10 to a first load 101. The second system supplies power of a second power supply 20 to a second load 103. The inter-system switch can cut off the first system and the second system from each other. When the primary ground fault detection unit detects ground fault, it cuts off the inter-system switch. The secondary ground fault detection unit monitors the system in which the ground fault is detected by the primary ground fault detection unit, and if the ground fault is resolved, reconnects the inter-system switch. When the inter-system switch is reconnected, the mask processing unit sets a cut-off inhibition period, and inhibits the cut-off of the inter-system switch in the cut-off inhibition period.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The disclosed embodiments relate to a power control device and a power control method.

Background Art

[0002] Conventionally, there is a redundant power supply system including a first system that supplies power of a first power supply to a first load, a second system that supplies power of a second power supply to a second load, and an inter-system switch that connects the first system and the second system. When the redundant power supply system detects that the voltage of the first system or the second system has dropped below a ground fault determination threshold, it shuts off the inter-system switch and identifies the grounded system (see, for example, Patent Document 1).

[0003] Then, after shutting off the inter-system switch, if the voltages of the first system and the second system return to equal to or higher than the ground fault determination threshold within a predetermined time, the redundant power supply system determines that it is normal, reconnects the inter-system switch, and returns to normal control.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a redundant power supply system, when the voltage of the first power supply is near the ground fault determination threshold due to aging deterioration or failure of the first power supply, the voltage drops below the ground fault determination threshold and then returns to equal to or higher than the ground fault determination threshold repeatedly. Therefore, the connection and disconnection of the inter-system switch are repeated, and the durability of the inter-system switch is reduced.

[0006] One aspect of the embodiments is made in view of the above, and an object thereof is to provide a power control device and a power control method capable of suppressing a reduction in the durability of an inter-system switch.

Means for Solving the Problem

[0007] The power supply control device according to one aspect of the embodiment includes a first system, a second system, an inter-system switch, a primary ground fault detection unit, a secondary ground fault detection unit, and a mask processing unit. The first system supplies the power of the first power supply to the first load. The second system supplies the power of the second power supply to the second load. The inter-system switch is provided in a connection path connecting the first system and the second system, and can connect and disconnect the first system and the second system. The primary ground fault detection unit shuts off the inter-system switch when detecting a ground fault in the first system or the second system. The secondary ground fault detection unit monitors the system in which the ground fault continues for a predetermined period when the ground fault is detected by the primary ground fault detection unit, and reconnects the inter-system switch if the ground fault has been eliminated. The mask processing unit sets a blocking prohibition period when the inter-system switch is reconnected, and prohibits the primary ground fault detection unit from blocking the inter-system switch during the blocking prohibition period.

Advantage of the Invention

[0008] The power supply control device and the power supply control method according to one aspect of the embodiment have an effect of suppressing a decrease in the durability of the inter-system switch.

Brief Description of the Drawings

[0009]

Figure 1

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BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments of the power control device and the power control method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments shown below. Hereinafter, a power control device mounted on a vehicle having an automatic driving function and supplying power to a load will be described as an example, but the power control device according to the embodiment may be mounted on a vehicle not having an automatic driving function.

[0011] In addition, hereinafter, the case where the vehicle on which the power control device is mounted is an electric vehicle or a hybrid vehicle will be described, but the vehicle on which the power control device is mounted may be an engine vehicle that runs by an internal combustion engine.

[0012] Note that the power control device according to the embodiment includes a first power source and a second power source, and may be mounted on any device that backs up the first power source with the other power source system when a power failure occurs in either the first power source system or the second power source system.

[0013] [1. Configuration of Power Control Device] FIG. 1 is an explanatory diagram showing a configuration example of a power control device according to an embodiment. As shown in FIG. 1, a power control device 1 according to the embodiment is connected to a first power source 10, a first load 101, a general load 102, a second load 103, and an automatic driving control device 100. The power control device 1 includes a first system 110 that supplies the power of the first power source 10 to the first load 101 and the general load 102, and a second system 120 that supplies the power of a second power source 20, which will be described later, to the second load 103.

[0014] The first load 101 includes loads for automatic driving. For example, the first load 101 includes a steering motor, an electric brake device, and an in-vehicle camera that operate during automatic driving. The general load 102 includes, for example, a display, an air conditioner, an audio, a video, and various lights.

[0015] The second load 103 includes a part of the functions for automatic driving included in the first load 101. For example, the second load 103 includes devices that are minimally necessary for FOP (fail operation) of a steering motor, an electric brake device, a radar, etc. The first load 101, the general load 102, and the second load 103 operate with the power supplied from the power control device 1.

[0016] The automatic driving control device 100 is a device that controls the automatic driving of a vehicle. The automatic driving control device 100 causes the vehicle to travel by automatic driving by operating the first load 101 and the second load 103. Further, when a ground fault occurs in the first system 110 during automatic driving, the automatic driving control device 100 can perform FOP with the second load 103, and when a ground fault occurs in the second system 120, the automatic driving control device 100 can perform FOP with the first load 101.

[0017] The first power supply 10 includes a DC / DC converter (hereinafter referred to as "DC / DC 11") and a lead battery (hereinafter referred to as "PbB 12"). Note that the battery of the first power supply 10 may be any secondary battery other than PbB 12.

[0018] DC / DC 11 is connected to a generator and a high-voltage battery having a voltage higher than that of PbB 12, steps down the voltages of the generator and the high-voltage battery, and outputs them to the first system 110. The generator is, for example, an alternator that generates electricity by converting the kinetic energy of a traveling vehicle into electricity. The high-voltage battery is, for example, a vehicle drive battery mounted on an electric vehicle or a hybrid vehicle.

[0019] Note that when the first power supply 10 is mounted on an engine vehicle, an alternator (generator) is provided instead of DC / DC 11. DC / DC 11 performs charging of PbB 12, power supply to the first load 101 and the general load 102, power supply to the second load 103, and charging of the second power supply 20 described later.

[0020] The power supply control device 1 includes a second power supply 20, an inter-system switch 41, a battery switch 42, a switch drive unit 3, a first voltage sensor 51, and a second voltage sensor 52. The second power supply 20 is a backup power supply when the power supply by the first power supply 10 becomes unavailable. The second power supply 20 includes a lithium-ion battery (hereinafter referred to as "LiB 21"). Note that the battery of the second power supply 20 may be any secondary battery other than LiB 21.

[0021] The inter-system switch 41 is provided on an inter-system line 130 that connects the first system 110 and the second system 120, and is a switch capable of connecting and disconnecting the first system 110 and the second system 120. The battery switch 42 is a switch that connects the second power supply 20 to the second system 120.

[0022] The first voltage sensor 51 is provided in the first system 110, detects the voltage of the first system 110, and outputs the detection result to the switch driving unit 3. The second voltage sensor 52 is provided in the second system 120, detects the voltage of the second system 120, and outputs the detection result to the switch driving unit 3.

[0023] The switch driving unit 3 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and various circuits. Note that the switch driving unit 3 may be configured by hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0024] The switch driving unit 3 includes a primary ground fault detection unit 31, a secondary ground fault detection unit 32, and a mask processing unit 33 that function by the CPU executing a program stored in the ROM using the RAM as a work area, and controls the operation of the power control device 1. A specific configuration example of the switch driving unit 3 will be described later with reference to FIG. 6. When activated, the switch driving unit 3 connects (turns on) the inter-system switch 41 and disconnects (turns off) the battery switch 42.

[0025] The switch driving unit 3 detects a ground fault in the first system 110 or the second system 120 based on the detection results input from the first voltage sensor 51 and the second voltage sensor 52. A specific example of the method for detecting a ground fault by the switch driving unit 3 will be described later.

[0026] When the switch driving unit 3 detects a ground fault in the first system 110 or the second system 120, it notifies the automatic driving control device 100 to that effect. When the switch driving unit 3 detects a ground fault in the first system 110 or the second system 120, it outputs an automatic driving prohibition signal indicating that the automatic driving is impossible to the automatic driving control device 100. Further, when the switch driving unit 3 does not detect a ground fault in the first system 110 or the second system 120, it outputs an automatic driving permission signal indicating that the automatic driving is possible to the automatic driving control device 100.

[0027] When a power supply failure such as a ground fault occurs in the first system 110, the switch driving unit 3 shuts off the inter-system switch 41, connects the battery switch 42, and supplies power from the second power supply 20 to the second load 103. Also, when a power supply failure such as a ground fault occurs in the second system 120, the switch driving unit 3 shuts off the inter-system switch 41 and supplies power from the first power supply 10 to the first load 101 and the general load 102 with the battery switch 42 in the off state.

[0028] Thereby, even if either one of the systems grounds during automatic driving, the power supply control device 1 can use the other system and implement a FOP to safely retreat the vehicle to a safe place by the automatic driving control device 100 and stop the vehicle. Next, with reference to FIGS. 2 to 5, the operation of the power supply control device 1 will be described.

[0029] [2. Normal operation of the power supply control device] In normal times when there is no ground fault in the first system 110 and the second system 120, as shown in FIG. 2, the switch driving unit 3 shuts off the battery switch 42, connects the inter-system switch 41, and supplies power from the first power supply 10 to the first load 101, the general load 102, and the second load 103. In normal times when there is no ground fault like this, the switch driving unit 3 outputs an automatic driving permission signal to the automatic driving control device 100.

[0030] [3. Operation of the power supply control device when a ground fault occurs] Next, with reference to FIGS. 3 to 5, the operation of the power control device 1 when a ground fault occurs will be described. As shown in FIG. 3, in the power control device 1, for example, when a ground fault 200 occurs in the first system 110 or a ground fault 201 occurs in the second system 120, an overcurrent flows toward the ground fault point, so that the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 become equal to or lower than the ground fault determination threshold value.

[0031] For this reason, when the voltage detected by the second voltage sensor 52, for example, becomes equal to or lower than the ground fault determination threshold value, the switch drive unit 3 tentatively determines that a ground fault 200 or 201 has occurred in the first system 110 or the second system 120, and outputs an automatic operation prohibition signal to the automatic operation control device 100. Then, when the switch drive unit 3 tentatively determines that a ground fault 200 or 201 has occurred, it disconnects the inter-system switch 41 and connects the battery switch 42. As a result, the connection between the first system 110 and the second system 120 is disconnected, power is supplied from the first power supply 10 to the first system 110, and power is supplied from the second power supply 20 to the second system 120.

[0032] Note that when the voltage detected by at least one of the first voltage sensor 51 and the second voltage sensor 52 becomes equal to or lower than the ground fault determination threshold value, the switch drive unit 3 can also tentatively determine that a ground fault has occurred in the first system 110 or the second system 120.

[0033] Thereafter, when the voltage detected by the first voltage sensor 51 is equal to or lower than the ground fault determination threshold value for a predetermined time or more and the voltage detected by the second voltage sensor 52 returns above the ground fault determination threshold value within the predetermined time, the switch drive unit 3 makes a final determination that a ground fault 200 has occurred in the first system 110.

[0034] In this case, as shown in FIG. 4, the switch drive unit 3 continues to supply power from the second power source 20 to the second load 103 by cutting off the inter-system switch 41 and connecting the battery switch 42, and notifies the automatic driving control device 100 to that effect. Thereby, the automatic driving control device 100 can operate the second load 103 with the power supplied from the second power source 20, and can drive the vehicle to a safe place and stop it. Note that the automatic driving control device 100 may be configured to start the evacuation driving when an automatic driving prohibition signal is input from the power control device 1.

[0035] Further, after temporarily determining that a ground fault has occurred in the first system 110 or the second system 120, if the voltage detected by the second voltage sensor 52 is equal to or lower than the ground fault determination threshold even after a predetermined time has elapsed, and the voltage detected by the first voltage sensor 51 has returned until it exceeds the ground fault determination threshold within the predetermined time, it is determined that a ground fault 201 has occurred in the second system 120.

[0036] In this case, as shown in FIG. 5, the switch drive unit 3 cuts off the battery switch 42 while continuing to cut off the inter-system switch 41, supplies power from the first power source 10 to the first load 101, and notifies the automatic driving control device 100 to that effect. Thereby, the automatic driving control device 100 can operate the first load 101 with the power supplied from the first power source 10, and can drive the vehicle to a safe place and stop it. Note that the automatic driving control device 100 may be configured to start the evacuation driving when an automatic driving prohibition signal is input from the power control device 1.

[0037] Further, in the power control device 1, when the first load 101 or the general load 102 is temporarily in an overload state, rather than a ground fault 200 or 201, the voltage detected by the first voltage sensor 51 may temporarily become equal to or lower than the ground fault determination threshold. Also, in the power control device 1, when the second load 103 is temporarily in an overload state, the voltage detected by the second voltage sensor 52 may temporarily become equal to or lower than the ground fault determination threshold.

[0038] In this case, in the power supply control device 1, power is continuously supplied from the first power supply 10 to the first load 101 and the general load 102, and power is supplied from the second power supply 20 to the second load 103. Therefore, after the switch driving unit 3 provisionally determines that a ground fault 200, 201 has occurred in the first system 110 or the second system 120, if the voltages detected by the first voltage sensor 51 and the second voltage sensor 52 return before a predetermined time elapses and both exceed the ground fault determination threshold value, it is determined that this is a transient voltage drop and there is no abnormality in the power supply. After that, in order to return to the normal operation shown in FIG. 2, the switch driving unit 3 disconnects the battery switch 42 and reconnects the inter-system switch 41.

[0039] [4. Configuration example of the switch driving unit according to the embodiment] Next, with reference to FIG. 6, a configuration example of the switch driving unit 3 according to the embodiment will be described. FIG. 6 is an explanatory diagram showing a configuration example of the switch driving unit 3 according to the embodiment. Note that FIG. 6 selectively shows the components related to the driving of the inter-system switch 41 among the components of the switch driving unit 3.

[0040] As shown in FIG. 6, the switch driving unit 3 includes a primary ground fault detection unit 31, a secondary ground fault detection unit 32, a mask processing unit 33, and an OR logic circuit 34. The detection results of the voltage of the first system 110 from the first voltage sensor 51 and the detection results of the voltage of the second system 120 from the second voltage sensor 52 are input to the primary ground fault detection unit 31 and the secondary ground fault detection unit 32.

[0041] When the primary ground fault detection unit 31 detects a ground fault in the first system 110 or the second system 120, it disconnects the inter-system switch 41. Specifically, when the voltage of the first system 110 or the voltage of the second system 120 becomes equal to or lower than the ground fault determination threshold value, the primary ground fault detection unit 31 outputs a primary ground fault detection signal to the OR logic circuit 34 and the secondary ground fault detection unit 32 via the mask processing unit 33. At this time, the primary ground fault detection unit 31 outputs a signal of a one-shot pulse of, for example, 50 ms. When the secondary ground fault detection unit 32 receives the primary ground fault detection signal from the primary ground fault detection unit 31, it outputs a secondary ground fault detection signal to the OR logic circuit 34.

[0042] In this way, during normal operation, the mask processing unit 33 outputs the primary ground fault detection signal from the primary ground fault detection unit 31 to the OR logic circuit 34 and the secondary ground fault detection unit 32 without masking it. When the inter-system switch 41 is reconnected, the mask processing unit 33 sets a cut-off prohibition period, which will be described later. During the cut-off prohibition period, the mask processing unit 33 masks the primary ground fault detection signal from the primary ground fault detection unit 31, thereby prohibiting the primary ground fault detection unit 31 from cutting off the inter-system switch. The details of the operation of the mask processing unit 33 will be described later.

[0043] When the OR logic circuit 34 receives the primary ground fault detection signal from the primary ground fault detection unit 31, it outputs the primary ground fault detection signal to the inter-system switch 41 to cut off the inter-system switch 41. After that, when the OR logic circuit 34 receives the secondary ground fault detection signal from the secondary ground fault detection unit 32, it outputs the secondary ground fault detection signal to the inter-system switch 41 to continue cutting off the inter-system switch 41. The secondary ground fault detection unit 32 determines the grounded system based on the detection results of the first and second voltage sensors 51 and 52. If the ground fault has been eliminated, it outputs a signal to reconnect the inter-system switch 41 to the OR logic circuit 34.

[0044] In addition, when the primary ground fault detection unit 31 detects a ground fault, the secondary ground fault detection unit 32 monitors the system in which the ground fault continues for a predetermined period. If the ground fault has been eliminated, it reconnects the inter-system switch 41. Specifically, when the primary ground fault detection unit 31 detects a ground fault, the secondary ground fault detection unit 32 samples the voltages of the first system 110 and the second system 120 at a predetermined period for a predetermined period.

[0045] When the secondary ground fault detection unit 32 samples a voltage exceeding the ground fault determination threshold continuously for a predetermined time (for example, 40 ms) or more, it determines that the ground fault does not continue and outputs a connection signal to reconnect the inter-system switch 41 to the OR logic circuit 34. When the OR logic circuit 34 receives the connection signal from the secondary ground fault detection unit 32, it outputs the connection signal to the inter-system switch 41 to reconnect the inter-system switch 41.

[0046] Here, when the voltage of the first power supply 10 is near the ground fault determination threshold due to aging deterioration or failure of the first power supply 10, it repeatedly decreases below the ground fault determination threshold and returns above the ground fault determination threshold. Therefore, the connection and disconnection of the inter-system switch 41 are repeated, and the durability of the inter-system switch 41 decreases. Such a problem also occurs when the voltage of the second power supply 20 is near the ground fault determination threshold.

[0047] Therefore, the switch driving unit 3 includes a mask processing unit 33. When the inter-system switch 41 is reconnected, the mask processing unit 33 sets a cut-off prohibition period, and prohibits the cut-off of the inter-system switch 41 by the primary ground fault detection unit 31 during the cut-off prohibition period. For example, when a signal indicating that the inter-system switch 41 is to be reconnected is input from the secondary ground fault detection unit 32, the mask processing unit 33 performs a mask process of blocking the output of the primary ground fault detection signal (one-shot pulse) from the primary ground fault detection unit 31 to the OR logic circuit 34 and the secondary ground fault detection unit 32 during the cut-off prohibition period.

[0048] Thereby, even if a ground fault is detected by the primary ground fault detection unit 31 immediately after the inter-system switch 41 is reconnected, the power control device 1 does not cut off the inter-system switch 41. Therefore, according to the power control device 1, it is possible to suppress a decrease in the durability of the inter-system switch 41 due to repeated connection and disconnection of the inter-system switch 41.

[0049] In addition, when a ground fault is detected again by the primary ground fault detection unit 31 within a predetermined time (for example, within 1.5 seconds) after the reconnection of the inter-system switch 41, the mask processing unit 33 extends the cut-off prohibition period. Thereby, the power control device 1 can further improve the durability of the inter-system switch 41 by further reducing the repetition frequency of connection and disconnection of the inter-system switch 41.

[0050] Furthermore, when the mask processing unit 33 extends the blocking prohibition period of the inter-system switch 41, it outputs an automatic driving prohibition signal for prohibiting automatic driving during the same trip to the automatic driving control device 100. Thereby, it is possible to prevent a transition to automatic driving in a situation where the voltage is unstable such that a ground fault is frequently detected by the primary ground fault detection unit 31.

[0051] [5. Operation Timing of Power Control Device] Next, the operation timing of the power control device will be described with reference to FIGS. 7 to 10. FIGS. 7 to 9 are timing charts showing the operation timing of the power control device according to the proportional example of the embodiment. FIG. 10 is a timing chart showing the operation timing of the power control device 1 according to the embodiment.

[0052] The first and second system voltages shown in FIGS. 7 to 10 are the voltages of the first system 110 and / or the second system 120. The ground fault determination threshold value is the threshold value of the voltage compared with the first and second system voltages. The primary ground fault detection unit detection signal is a primary ground fault detection signal that changes from Low to High at the timing when the primary ground fault detection unit 31 detects a ground fault.

[0053] The secondary ground fault detection unit detection signal changes from Low to High when it receives the primary ground fault detection signal output from the primary ground fault detection unit 31. Thereafter, when the ground fault is confirmed by the secondary ground fault detection unit 32, it continues to be High. Also, when it is determined by the secondary ground fault detection unit 32 that the ground fault is not continuing, it is a signal that changes from High to Low. This signal that changes from High to Low becomes the connection signal for reconnecting the inter-system switch 41. The blocking determination period is the counter value that is counted up while the secondary ground fault detection unit 32 determines the presence or absence of the continuation of the ground fault after the ground fault is detected by the primary ground fault detection unit 31 (for example, 1000 ms).

[0054] The abnormal determination is a counter value that is incremented by the secondary ground fault detection unit 32 while the first and second system voltages are determined to be equal to or lower than the ground fault determination threshold, and is reset when the first and second system voltages become equal to or higher than the ground fault determination threshold. The normal determination is a counter value that is incremented by the secondary ground fault detection unit 32 while the first and second system voltages are determined to exceed the ground fault determination threshold, and is reset when the first and second system voltages become equal to or lower than the ground fault determination threshold.

[0055] The inter-system switch connection state changes from Low to High at the timing when the inter-system switch 41 switches from connected to disconnected, and changes from High to Low at the timing when it switches from disconnected to connected. The cutoff prohibition signal shown in FIG. 10 is a signal output by the mask processing unit 33 according to the embodiment to prohibit the cutoff of the inter-system switch 41. The primary ground fault detection unit 31 according to the modification prohibits the cutoff of the inter-system switch 41 during the period when the cutoff prohibition signal is High.

[0056] As shown in FIG. 7, when the first and second system voltages become equal to or lower than the ground fault determination threshold at time t1, the primary ground fault detection unit 31 according to the modification outputs a primary ground fault detection signal (one-shot pulse) to the OR logic circuit 34 and the secondary ground fault detection unit 32. Thereby, the inter-system switch 41 is cut off at time t1 by the primary ground fault detection signal via the OR logic circuit 34. Further, when the secondary ground fault detection unit 32 detects the primary ground fault detection signal, it tentatively determines that a ground fault has occurred, and outputs a secondary ground fault detection signal to the OR logic circuit 34 at a timing slightly delayed from time t1. Thereby, the inter-system switch 41 maintains the cutoff state.

[0057] After time t1, since the first and second system voltages continue to be equal to or lower than the ground fault determination threshold, the count value of the abnormal determination increases. The secondary ground fault detection unit 32 continues to increase the count value of the abnormal determination, and finally determines that a ground fault has occurred at time t2 when 1000 ms of the cutoff determination period has elapsed since time t1.

[0058] Also, as shown in FIG. 8, when the first and second line voltages become equal to or lower than the ground fault determination threshold value at time t11, the primary ground fault detection unit 31 according to the modification example outputs a one-shot pulse. As a result, similar to the example shown in FIG. 7, the inter-system switch 41 is interrupted at time t11.

[0059] Thereafter, the counter value for abnormality determination increases until time t12 when the first and second line voltages exceed the ground fault determination threshold value. When the first and second line voltages exceed the ground fault determination threshold value, the counter value for abnormality determination is reset, and the counter value for normal determination increases.

[0060] When the increase in the counter value for normal determination continues for a predetermined time (40 ms) within the interruption determination period, the secondary ground fault detection unit 32 determines that no ground fault has occurred at time t13. As a result, the inter-system switch 41 is reconnected at time t13.

[0061] Also, as shown in FIG. 9, the first and second line voltages may repeatedly fluctuate near the ground fault determination threshold value. In this case, the switch drive unit according to the proportionality may frequently interrupt and reconnect the inter-system switch 41.

[0062] For example, as shown in FIG. 9, when the first and second line voltages become equal to or lower than the ground fault determination threshold value at time t21, the switch drive unit according to the proportionality interrupts the inter-system switch 41. Thereafter, between times t22 and t23, although the first and second line voltages exceed the ground fault determination threshold value, the increase in the counter value for normal determination ends in a time (time t23) shorter than 40 ms. Therefore, here, the inter-system switch 41 is not reconnected. Between times t23 and t25, the first and second line voltages become equal to or lower than the ground fault determination threshold value, but the inter-system switch 41 maintains the interrupted state.

[0063] Thereafter, since the first and second line voltages continuously exceed the ground fault determination threshold value for 40 ms between times t25 and t26, the switch drive unit according to the proportionality reconnects the inter-system switch 41 at time t26. When the first and second line voltages become equal to or lower than the ground fault determination threshold value at time t27, the inter-system switch 41 is interrupted again.

[0064] Thereafter, since the first and second system voltages continuously exceed the ground fault determination threshold value during the 40 ms from time t28 to t29, the switch drive unit related to the proportional ratio reconnects the inter-system switch 41 at time t29. When the first and second system voltages become equal to or lower than the ground fault determination threshold value at time t30, the inter-system switch 41 is cut off three times.

[0065] Thereafter, since the first and second system voltages continuously exceed the ground fault determination threshold value during the 40 ms from time t31 to t32, the switch drive unit related to the proportional ratio reconnects the inter-system switch 41 at time t32. When the first and second system voltages become equal to or lower than the ground fault determination threshold value at time t33, the inter-system switch 41 is cut off four times. In this way, the switch drive unit related to the proportional ratio may frequently perform cutoff and reconnection of the inter-system switch 41.

[0066] On the other hand, since the switch drive unit 3 according to the embodiment drives and controls the inter-system switch 41 as shown in FIG. 10, the number of connection times and the number of cutoff times of the inter-system switch 41 can be reduced as compared with the switch drive unit related to the proportional ratio.

[0067] The waveforms of the first and second system voltages shown in FIG. 10 are the same waveforms as the waveforms of the first and second system voltages shown in FIG. 9. As shown in FIG. 10, the switch drive unit 3 according to the embodiment performs the same drive control as the switch drive unit related to the proportional ratio from time t21 to t26. However, when the inter-system switch 41 is reconnected at time t26, the mask processing unit 33 sets a cutoff prohibition period for the inter-system switch 41.

[0068] As a result, even if a ground fault is detected by the primary ground fault detection unit 31 at time t27 immediately after the inter-system switch 41 is reconnected by the switch drive unit 3 at time t26, the primary ground fault detection signal is masked by the mask processing unit 33, and the inter-system switch 41 is not cut off.

[0069] Thereafter, between time t27 and t28, although the first and second system voltages are below the ground fault determination threshold value, since the first and second system voltages do not transition from a value exceeding the ground fault determination threshold value to a value below the ground fault determination threshold value, the count value of the abnormality determination does not increase. Also, during this period, since the inter-system switch 41 maintains the connected (on) state, the count value of the normal determination does not increase either.

[0070] Therefore, in the switch driving unit related to the proportionality, the inter-system switch 41 was connected at time t29, whereas the switch driving unit 3 according to the embodiment does not perform its switching operation. Thereafter, when the first and second system voltages become below the ground fault determination threshold value at time t30, the switch driving unit 3 disconnects the inter-system switch 41.

[0071] Thereafter, when the time during which the first and second system voltages are equal to or higher than the ground fault determination threshold value reaches a predetermined time (from time t31 to t32), the switch driving unit 3 sets the cutoff prohibition period of the inter-system switch 41 again at time t32. The cutoff prohibition signal is generated (switches from Low to High) when reconnecting the inter-system switch 41 (at time t32). However, the mask processing unit 33 starts the mask processing before the inter-system switch 41 is reconnected. This is to prevent voltage fluctuations from occurring when the inter-system switch 41 is reconnected and to prevent the primary ground fault detection signal from passing through the mask processing unit 33 due to such fluctuations.

[0072] Also, if a ground fault is detected again by the primary ground fault detection unit 31 within a predetermined time (for example, at time t30) after the previous reconnection of the inter-system switch 41, the switch driving unit 3 extends the cutoff prohibition period (from time t32 to t34). Note that the condition for extending the cutoff prohibition period, "after the reconnection of the inter-system switch 41", is a concept that includes "after the setting of the cutoff prohibition period" and "after the expiration of the cutoff prohibition period". This is because the reconnection of the inter-system switch 41 and the setting of the cutoff prohibition period correspond one-to-one.

[0073] As a result, in the switch driving unit related to the proportional control, the inter-system switch 41 was cut off at time t33, whereas the switch driving unit 3 according to the embodiment does not perform the switching operation. Thus, when reconnecting the inter-system switch 41, the switch driving unit 3 according to the embodiment can reduce the number of connection times and disconnection times of the inter-system switch 41 compared with the switch driving unit related to the proportional control by setting a cut-off prohibition period of the inter-system switch 41.

[0074] [6. Processing Executed by Switch Driving Unit] Next, with reference to FIG. 11, the processing executed by the switch driving unit 3 of the power control device 1 will be described. FIG. 11 is a flowchart showing an example of the processing executed by the switch driving unit 3 of the power control device 1 according to the embodiment.

[0075] During normal operation, the switch driving unit 3 determines whether or not a ground fault has been detected by the primary ground fault detection unit 31 (step S101). If the switch driving unit 3 determines that no ground fault has been detected (step S101, No), the process ends and the process starts again from step S101.

[0076] If the switch driving unit 3 determines that a ground fault has been detected (step S101, Yes), it cuts off the inter-system switch 41 (step S102) and determines whether or not the ground fault has been confirmed as a result of monitoring by the secondary ground fault detection unit 32 (step S103). If the switch driving unit 3 determines that the ground fault has been confirmed (step S103, Yes), it performs FOP in the system without a ground fault (step S110) and ends the process.

[0077] When the switch drive unit 3 determines that the ground fault has not been confirmed (No in step S103), it determines whether the ground fault has been eliminated (step S104). When the switch drive unit 3 determines that the ground fault has not been eliminated (No in step S104), it transfers the process to step S103. Further, when the switch drive unit 3 determines that the ground fault has been eliminated (Yes in step S104), it determines whether the current ground fault has been detected by the primary ground fault detection unit 31 within a predetermined time after the reconnection of the inter-system switch 41 last time (step S105).

[0078] When the switch drive unit 3 determines that the ground fault has not been detected within the predetermined time (No in step S105), it sets the cutoff prohibition period of the inter-system switch 41 (step S106), reconnects the inter-system switch 41 (step S107), and ends the process. That is, when the ground fault is detected in step S101 and it is determined in step S104 that the ground fault has been eliminated, and this is the first time during this trip (the period when the ignition switch is on this time), or when the ground fault is detected again within the predetermined time after the expiration of the previous cutoff prohibition period, the cutoff prohibition period, which is the standard value, is set.

[0079] When the switch drive unit 3 determines that the ground fault has been detected within the predetermined time (Yes in step S105), it extends the cutoff prohibition period (step S108), prohibits the automatic operation during the same trip (step S109), and transfers to step S107.

[0080] [Configuration example of switch drive unit according to modification example 7] Next, with reference to FIG. 12, a configuration example of the switch drive unit 3a according to a modification example of the embodiment will be described. FIG. 12 is an explanatory diagram showing a configuration example of the switch drive unit 3a according to a modification example of the embodiment. Note that FIG. 12 selectively shows the components related to the drive of the inter-system switch 41 among the components of the switch drive unit 3a.

[0081] As shown in FIG. 12, in addition to the components included in the switch driving unit 3 shown in FIG. 6, the switch driving unit 3a further includes a frequency detection unit 35 and a cutoff prohibition unit 36. The frequency detection unit 35 detects the frequency of the interruption of the inter-system switch 41 by the primary ground fault detection unit 31 and the reconnection of the inter-system switch 41 by the secondary ground fault detection unit 32.

[0082] When a primary ground fault detection signal is output from the primary ground fault detection unit 31 to the secondary ground fault detection unit 32, the frequency detection unit 35 acquires the cutoff timing of the inter-system switch 41 by the primary ground fault detection unit 31 based on the secondary ground fault detection signal input from the secondary ground fault detection unit 32.

[0083] When it is determined by the secondary ground fault detection unit 32 that the ground fault is not continuing, the frequency detection unit 35 acquires the reconnection timing of the inter-system switch 41 by the secondary ground fault detection unit 32 based on the input of the connection signal from the secondary ground fault detection unit 32.

[0084] The frequency detection unit 35 detects the frequency of the interruption and reconnection of the inter-system switch 41 from the acquired cutoff timing of the inter-system switch 41 by the primary ground fault detection unit 31 and the reconnection timing of the inter-system switch 41 by the secondary ground fault detection unit 32. For example, when the interruption and reconnection of the inter-system switch 41 are counted as one time, the frequency detection unit 35 can use the number of cutoff-reconnection times in a predetermined period (e.g., 3 minutes) as the frequency.

[0085] Then, the frequency detection unit 35 outputs the detected frequency information to the cutoff prohibition unit 36. Also, the frequency detection unit 35 outputs the detected frequency to the mask processing unit 33 via the secondary ground fault detection unit 32. Note that the frequency detection unit 35 may detect only the cutoff frequency of the inter-system switch 41 as the frequency, or may detect only the reconnection frequency of the inter-system switch 41 as the frequency. Also, the frequency detection unit 35 may detect the length of time from the cutoff of the inter-system switch 41 to the reconnection and the length of time from the reconnection to the re-cutoff as the frequency.

[0086] When the frequency of disconnection and reconnection of the inter-system switch 41 is equal to or higher than a predetermined frequency, the disconnection prohibition unit 36 prohibits the disconnection of the inter-system switch 41. Thereby, the power supply control device 1a can suppress a decrease in the durability of the inter-system switch 41 by suppressing frequent disconnection and reconnection of the inter-system switch 41.

[0087] When the inter-system switch 41 is reconnected by the secondary ground fault detection unit 32, the mask processing unit 33 sets a disconnection prohibition period for prohibiting the disconnection of the inter-system switch 41 by the disconnection prohibition unit 36. Thereby, the power supply control device 1a can suppress a decrease in the durability of the inter-system switch 41 due to repeated connection and disconnection of the inter-system switch 41.

[0088] Further, when the frequency detected by the frequency detection unit 35 is equal to or higher than a predetermined frequency, the mask processing unit 33 extends the disconnection prohibition period of the inter-system switch 41. Thereby, the power supply control device 1a can further improve the durability of the inter-system switch 41 by further reducing the repetition frequency of connection and disconnection of the inter-system switch 41.

[0089] Also, when the frequency detected by the frequency detection unit 35 is equal to or higher than a predetermined frequency, the disconnection prohibition unit 36 prohibits the disconnection of the inter-system switch 41 during the same trip. Thereby, the power supply control device 1a can suppress the vehicle behavior from becoming unstable during the same trip due to repeated disconnection and reconnection of the inter-system switch 41.

[0090] [Processing Executed by Switch Driving Unit According to Modification Example] Next, the processing executed by the switch driving unit 3a according to a modification example of the embodiment will be described with reference to FIG. 13. FIG. 13 is a flowchart showing an example of the processing executed by the switch driving unit 3a according to a modification example of the embodiment.

[0091] During normal operation, the switch driving unit 3a determines whether a ground fault has been detected by the primary ground fault detection unit 31 (step S201). If the switch driving unit 3a determines that no ground fault has been detected (step S201, No), the process ends, and the process starts again from step S201.

[0092] If the switch driving unit 3a determines that a ground fault has been detected (step S201, Yes), it shuts off the inter-system switch 41 (step S202) and determines whether the ground fault has been confirmed based on the monitoring result of the secondary ground fault detection unit 32 (step S203). If the switch driving unit 3a determines that the ground fault has been confirmed (step S203, Yes), it performs FOP on the non-grounded system (step S210) and ends the process.

[0093] If the switch driving unit 3a determines that the ground fault has not been confirmed (step S203, No), it determines whether the ground fault has been eliminated (step S204). If the switch driving unit 3a determines that the ground fault has not been eliminated (step S204, No), the process moves to step S203.

[0094] Also, if the switch driving unit 3a determines that the ground fault has been eliminated (step S204, Yes), it determines whether the frequency of shutting off the inter-system switch 41 and reconnecting the inter-system switch 41 by the secondary ground fault detection unit 32 is equal to or higher than a predetermined frequency (step S205).

[0095] If the switch driving unit 3a determines that the frequency is equal to or higher than the predetermined frequency (step S205, Yes), it extends the cutoff prohibition period (step S208), prohibits the reconnection of the inter-system switch 41 during the same trip (step S209), and ends the process.

[0096] Further, when the switch driving unit 3a determines that the frequency of disconnection of the inter-system switch 41 and reconnection of the inter-system switch 41 by the secondary ground fault detection unit 32 is not equal to or higher than a predetermined frequency (step S205, No), the switch driving unit 3a sets a disconnection prohibition period for the inter-system switch 41 (step S206), reconnects the inter-system switch 41 (step S207), and ends the process.

[0097] Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments presented and described as above. Accordingly, various changes are possible without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Reference Numerals

[0098] 1, 1a Power control device 10 First power source 11 DC / DC 12 PbB 20 Second power source 21 LiB 3, 3a Switch driving unit 31 Primary ground fault detection unit 32 Secondary ground fault detection unit 33 Mask processing unit 34 OR logic circuit 35 Frequency detection unit 36 Disconnection prohibition unit 41 Inter-system switch 42 Battery switch 51 First voltage sensor 52 Second voltage sensor 100 Automatic driving control device 101 First load 102 General load 103 Second load 110 First system 120 Second system

Claims

1. A first system that supplies the power of a first power source to a first load, A second system that supplies the power of a second power source to a second load, An inter-system switch provided in a connection path connecting the first system and the second system, capable of connecting and disconnecting the first system and the second system, A primary ground fault detection unit that shuts off the inter-system switch when detecting a ground fault in the first system or the second system, When a ground fault is detected by the primary ground fault detection unit, a secondary ground fault detection unit that monitors the system in which the ground fault continues for a predetermined period and reconnects the inter-system switch if the ground fault has been eliminated, A mask processing unit that sets a blocking prohibition period when the inter-system switch is reconnected, and prohibits the blocking of the inter-system switch by the primary ground fault detection unit during the blocking prohibition period A power control device characterized by comprising the above.

2. The mask processing unit, When a ground fault is detected again by the primary ground fault detection unit within a predetermined time after the reconnection of the inter-system switch, extends the blocking prohibition period The power control device according to claim 1, characterized by the above.

3. The mask processing unit, When extending the blocking prohibition period, prohibits automatic operation during the same trip The power control device according to claim 2, characterized by the above.

4. A first system that supplies the power of a first power source to a first load, A second system that supplies the power of a second power source to a second load, An inter-system switch provided in a connection path connecting the first system and the second system, capable of connecting and disconnecting the first system and the second system, A primary ground fault detection unit that shuts off the inter-system switch when detecting a ground fault in the first system or the second system, When a ground fault is detected by the primary ground fault detection unit, a secondary ground fault detection unit that monitors the system in which the ground fault continues for a predetermined period and reconnects the inter-system switch if the ground fault has been eliminated, A frequency detection unit that detects the frequency of the blocking of the inter-system switch by the primary ground fault detection unit and the reconnection of the inter-system switch by the secondary ground fault detection unit, A blocking prohibition unit that prohibits the blocking of the inter-system switch when the frequency is equal to or higher than a predetermined frequency A power control device characterized by comprising the above.

5. When the inter-system switch is reconnected by the secondary ground fault detection unit, further comprising a mask processing unit that sets a blocking prohibition period for prohibiting the blocking of the inter-system switch by the blocking prohibition unit, The mask processing unit, When the frequency is equal to or higher than a predetermined frequency, extend the cutoff prohibition period. The power control device according to claim 4, characterized in that.

6. The cutoff prohibition unit When the frequency is equal to or higher than a predetermined frequency, prohibits cutoff of the inter-system switch during the same trip. The power control device according to claim 4 or claim 5, characterized in that.

7. A first system that supplies power of a first power source to a first load, A second system that supplies power of a second power source to a second load, An inter-system switch provided in a connection path connecting the first system and the second system and capable of connecting and disconnecting the first system and the second system The primary ground fault detection unit of the power control device including A primary ground fault detection step of detecting a ground fault in the first system or the second system and cutting off the inter-system switch, The secondary ground fault detection unit of the power control device When a ground fault is detected by the primary ground fault detection unit, monitors the system in which the ground fault continues for a predetermined period, and if the ground fault has been eliminated, reconnects the inter-system switch. A secondary ground fault detection step, The mask processing unit of the power control device When the inter-system switch is reconnected, sets a cutoff prohibition period, and prohibits cutoff of the inter-system switch by the primary ground fault detection unit during the cutoff prohibition period. A mask processing step A power control method characterized by including.

8. A first system that supplies power of a first power source to a first load, A second system that supplies power of a second power source to a second load, An inter-system switch provided in a connection path connecting the first system and the second system and capable of connecting and disconnecting the first system and the second system The primary ground fault detection unit of the power control device including A primary ground fault detection step of detecting a ground fault in the first system or the second system and cutting off the inter-system switch, The secondary ground fault detection unit of the power control device When a ground fault is detected by the primary ground fault detection unit, monitors the system in which the ground fault continues for a predetermined period, and if the ground fault has been eliminated, reconnects the inter-system switch. A secondary ground fault detection step, The frequency detection unit of the power control device A frequency detection step of detecting the frequency of cutoff of the inter-system switch by the primary ground fault detection unit and reconnection of the inter-system switch by the secondary ground fault detection unit, The cutoff prohibition unit of the power control device A cutoff prohibition step of prohibiting cutoff of the inter-system switch when the frequency is equal to or higher than a predetermined frequency A power control method characterized by including.

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