Vehicular control device

Abstract

To provide a technique which can prevent faults of a semi-conductor switching element through restricting release chance of prohibition control of electric conduction to a load circuit by the semi-conductor switching element.SOLUTION: A heater control device 1 activates, when abnormality of electrification to a deicer 3 is detected, a protection circuit of IPD4c to perform prohibition control of electrification to the deicer 3. When the number of the prohibition control of electrification to the deicer 3 is less than ten times during one trip period from the time when IG switch 9 is turned on till the time when the ON setting is turned OFF, the prohibition control of electrification is released when a crewman performs OFF operation of a deicer SW11. When the number of the prohibition control of electrification to the deicer 3 is ten times or more during one trip period, the prohibition control of electrification is released when a crewman performs OFF operation of the deicer SW11 after the IG switch 9 is turned OFF.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that controls power supply to a predetermined load circuit provided in a vehicle. [Background technology]

[0002] A vehicle is provided with various load circuits to which power is supplied from a battery. Since the load circuits may be damaged by long-term current supply or overcurrent, a technique for preventing such damage to the load circuits has been proposed (for example, Patent Document 1). In Patent Document 1, an IPD (Intelligent Power Device) is used as a semiconductor switching element used to control current supply to the load circuits. In addition to a function for supplying and stopping current, the IPD is provided with a self-protection function, and performs self-protection and stops the current supply when an overcurrent occurs or when external noise is superimposed on the current. Then, when a certain time has elapsed since the current supply was stopped, a retry process is performed, and the current supply is resumed by the process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-12972 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, one type of IPD failure is an ON failure in which the switch unit is always in an ON state. When an ON failure occurs in an IPD, there is no way to cut off the power supply, and if electricity is passed for a long time or an overcurrent flows to the load circuit in this state, the load circuit may be damaged. One of the causes of such an ON failure is thought to be the accumulation of damage to the IPD due to the activation of the self-protection function. Therefore, in the technology described in Patent Document 1, if the retry process is made easy, the damage to the IPD is likely to accumulate, which poses a problem that the IPD is likely to fail.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology that can prevent failure of semiconductor switching elements by limiting the triggers for releasing the control that prohibits the flow of current to a load circuit by the semiconductor switching element. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the vehicle control device of the present invention comprises a semiconductor switching element capable of controlling the flow of current to a specified load circuit, and a control means that performs prohibition control to prohibit the semiconductor switching element from passing current to the specified load circuit, and release control to release the prohibition control, wherein the control means performs the prohibition control when it detects an abnormality in at least one of the load circuit and the semiconductor switching element, and performs release control at a specified trigger when an index value indicating the number of times the control means has performed the prohibition control during an on duration, which is the period from when the vehicle power supply is set to on to when the on duration is set to off, is less than a specified value, and performs release control at least until the vehicle power supply is set to off when the index value during the on duration is equal to or greater than the specified value. Effect of the Invention

[0007] According to this configuration, if the number of times inhibition control of the semiconductor switching element is performed during the period from when the vehicle power supply is set to on until it is set to off (on duration) is equal to or greater than a predetermined value, the inhibition control is not released until the vehicle power supply is set to off. In this way, since release control is not easily performed when the number of times inhibition control is performed is equal to or greater than the predetermined value, the number of times inhibition control and release control are repeated can be reduced. As a result, the accumulation of damage to the semiconductor switching element can be reduced, and failure of the semiconductor switching element can be prevented. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a heater control device according to an embodiment of the present invention; [Diagram 2] 2 is a flowchart for explaining the operation of FIG. 1. [Diagram 3] 3 is a flowchart for explaining the operation of FIG. 1, which is a sequel to FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Embodiment> A heater control device according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic configuration diagram of a heater control device according to one embodiment of the present invention.

[0010] (Schematic configuration of heater control device) A heater control device 1 (corresponding to the "vehicle control device" of the present invention) according to a first embodiment of the present application is provided in a vehicle and controls the operation of a PTC heater that heats the vehicle's conditioned air and the operation of a deicer that prevents the wipers from freezing. As shown in Fig. 1, the heater control device 1 includes a PTC heater 2 that heats the conditioned air, a deicer 3 that is provided on the windshield of the vehicle, a heater module 4 that controls the operation of the deicer 3 and the PTC heater 2, a battery 6 that supplies power to various devices provided in the vehicle, an AUTO A / C 7, and a MAX-HOT switch 10.

[0011] The PTC heater 2 (corresponding to an example of the "load circuit" of the present invention) is a heater that uses a PTC (Positive Temperature Coefficient) element for heating. Air conditioning of a vehicle usually uses engine coolant as a heat source, but this heater supplements the insufficient heat when blowing warm air when the engine coolant is at a low temperature. For example, a ceramic semiconductor whose electrical resistance value rises sharply above the Curie temperature can be used as the PTC element. In this embodiment, three PTC heaters 2 are provided, and each is driven and controlled by a heater module 4. In the following, when the individual PTC heaters 2 are to be distinguished from one another, they are referred to as PTC heater 2a, PTC heater 2b, and PTC heater 2c, and when they are not to be distinguished from one another, they are collectively referred to as PTC heater 2.

[0012] The deicer 3 (corresponding to an example of the "load circuit" of the present invention) prevents the wipers of the vehicle from freezing. In this embodiment, the deicer 3 is made of a heating wire and is disposed near the stop position of the wiper blades on the windshield.

[0013] The heater module 4 controls the driving of the PTC heater 2 and the deicer 3. The heater module 4 includes a control unit 4a configured with a CPU, a storage unit 4b configured with ROM and RAM, and a plurality of IPDs (Intelligent Power Devices) 4c that switch between energizing and deenergizing the PTC heater 2 and the deicer 3. Here, the control unit 4a (corresponding to the "control means" of the present invention) controls the driving of the PTC heater 2 and the deicer 3, and the storage unit 4b stores various control programs and data necessary for the control.

[0014] The IPD 4c (corresponding to the "semiconductor switching element" of the present invention) includes a switch element (in this embodiment, a FET (field effect transistor)) capable of switching between energization and de-energization of the connected load (PTC heaters 2a-2c, de-icer 3), a protection circuit, and a current sensor. The switch element receives a control signal from the control unit 4a, which will be described later, and switches between energization and de-energization of the connected load (PTC heaters 2a-2c, de-icer 3). When the switch element is set to ON, the current supplied from the battery 6 flows to the load (PTC heaters 2a-2c, de-icer 3), and when the switch element is set to OFF, the supply of current from the battery 6 to the load (PTC heaters 2a-2c, de-icer 3) is cut off.

[0015] The current sensor detects the value of the current supplied to the load (PTC heaters 2a-2c, deicer 3) and outputs information about the current value to the control unit 4a (feedback of the current value supplied to the load). The protection circuit performs self-protection when an overcurrent occurs in the IPD 4c or when external noise is superimposed on the current, and automatically stops the supply of current to the load (PTC heaters 2a-2c, deicer 3) without waiting for a command from the control unit 4a. The drive control of the PTC heater 2 and deicer 3 by the control unit 4a will be described later.

[0016] The deicer SW11 is a switch that allows a passenger to instruct ON / OFF of the deicer 3. The deicer SW11 is connected to the heater module 4, so that the control unit 4a of the heater module 4 can detect the ON / OFF setting state of the deicer SW11.

[0017] The AUTO A / C 7 manages the set temperature of the vehicle's air conditioning and outputs information about the set temperature of the air conditioner (air conditioning) set by the occupant to the heater module 4.

[0018] The MAX-HOT switch 10 is a switch that is set to ON when the set temperature of the air conditioner is set to the maximum value of the set range. The MAX-HOT switch 10 is connected to the heater module 4, so that the control unit 4a of the heater module 4 can detect the ON / OFF setting state.

[0019] Next, the drive control of the PTC heater 2 and the deicer 3 by the heater module 4 will be described. In this embodiment, the drive control of the PTC heater 2 and the deicer 3 by the heater module 4 is performed in different ways: normal control, control when the estimated temperature of the wiring (harness) of the load (PTC heater 2, deicer 3) becomes higher than the upper limit value, and control when the protection circuit of the IPD 4c is activated. Each type of control will be described below.

[0020] (Normal heater drive control) Normally, when a predetermined PTC drive start condition is satisfied, the control unit 4a transmits a control signal (energization request signal) to each IPD 4c, which sets the switch element of the IPD 4c to ON, thereby starting the energization of each PTC heater 2. When a predetermined PTC stop condition is satisfied, the control unit 4a transmits a control signal (energization stop request signal), which sets the switch element of the IPD 4c to OFF, thereby stopping the energization of each PTC heater 2. The PTC drive start condition includes, for example, that the MAX-HOT switch 10 is set to ON, that the outside air temperature is equal to or lower than a predetermined value, and that the coolant temperature is equal to or lower than a predetermined value. The predetermined PTC stop condition includes, for example, that the temperature of the engine coolant is equal to or higher than a predetermined value.

[0021] Similarly, when the occupant turns on the deicer SW11, the control unit 4a normally sends a control signal (energization request signal) to the IPD 4c connected to the deicer 3, which sets the switch element of the IPD switch 4c to ON, thereby starting the supply of electricity to the deicer 3. Furthermore, when the occupant turns off the deicer SW11 while electricity is being supplied to the deicer 3, the control unit 4a sends a control signal (energization stop request signal) to the IPD 4c connected to the deicer 3, which sets the switch element of the IPD switch 4c to OFF, thereby stopping the supply of electricity to the deicer 3.

[0022] As described above, in this embodiment, in addition to the normal control described above, the control unit 4a performs control different from normal control when the estimated temperature of the harness exceeds a predetermined upper limit value or when the protection circuit of the IPD 4c is activated. Below, the control when the estimated temperature of the harness reaches the upper limit value and when the protection circuit of the IPD 4c is activated will be described using the case of the current control of the deicer 3 as an example. Note that the control described below can also be applied to the drive control of the PTC heater 2.

[0023] (Drive control when the estimated wiring temperature reaches the upper limit) The control unit 4a estimates the temperature of the wiring (harness) of the deicer 3 based on information related to the current value supplied to the deicer 3. The information is output from a current sensor of the IPD 4c to the control unit 4a. As a method for estimating the temperature of the harness, for example, the conventional techniques described in Japanese Patent No. 5390837, Japanese Patent No. 5768176, Japanese Patent No. 6322536, Japanese Patent No. 6128055, Japanese Patent No. 6790350, etc. can be used.

[0024] Programs and various data required for estimating the temperature of the wiring (harness) are stored in the storage unit 4b.

[0025] When the estimated temperature of the wiring (harness) of the deicer 3 is not higher than the upper limit, the control unit 4a transmits a control signal to the IPD 4c according to the ON / OFF operation of the deicer SW11 by the occupant through the normal control described above. On the other hand, when the estimated temperature of the wiring (harness) of the deicer 3 is higher than the upper limit, even if the occupant does not operate the deicer SW11 to OFF, the control unit 4a transmits a control signal (power stop request signal) to the IPD 4c connected to the deicer 3, thereby setting the switch element of the IPD switch 4c to OFF, thereby stopping the power supply to the deicer 3.

[0026] After the power supply is stopped, the control unit 4a prohibits power supply to the deicer 3 (power supply prohibition control) until the occupant turns off the deicer SW11. When the occupant turns off the deicer SW11, the control unit 4a cancels the power supply prohibition control and returns to normal control. Therefore, thereafter, when the occupant turns on the deicer SW11, the control unit 4a transmits a control signal (power supply request signal) to the IPD 4c, which sets the switch element of the IPD switch 4c to ON, thereby restarting power supply to the deicer 3.

[0027] (Drive control when the protection circuit is activated) When an overcurrent flows through the IPD 4c or the deicer 3 (including the wiring (harness) connecting the IPD 4c and the deicer), or when external noise is superimposed on the current value, the IPD 4c activates a protection circuit, which stops the supply of current to the deicer 3. The current supply is automatically stopped even without a control signal from the control unit 4a (self-protection function of the IPD 4c). When the control unit 4a detects the activation of the protection circuit of the IPD 4c, it increments the value of a protection function activation count counter (cumulative) 4b1, which counts the cumulative number of times the protection function has been activated. In addition to incrementing the value of the protection function activation count counter (cumulative) 4b1, the control unit 4a also increments the value of a protection function activation count counter (1 trip) 4b2, which counts the number of times the self-protection function has been activated during the period from when the IG switch 9 is set to ON to when the ON setting is set to OFF (hereinafter referred to as 1 trip period (corresponding to the "on duration" of the present invention)). The control unit 4a is capable of detecting whether or not the protection circuit of the IPD 4c has been activated.

[0028] Both the protection function activation count counter (cumulative) 4b1 and the protection function activation count counter (1 trip) 4b2 are set in a predetermined storage area of ​​the RAM constituting the storage unit 4b of the heater module 4 (see FIG. 1). The value of the protection function activation count counter (cumulative) 4b1 is never cleared, but the protection function activation count counter (1 trip) 4b2 is cleared to 0 by the control unit 4a when the IG switch 9 is turned OFF. The protection function activation count corresponds to the "index value" of the "index value indicating the number of times the control means has performed inhibition control" of the present invention. The index value is not limited to the protection function activation count, and may be, for example, the number of times inhibition control has been restored to normal control (the number of release control).

[0029] The power supply inhibition control caused by the operation of the protection circuit of IPD4c is released or continued as follows.

[0030] (Continuation of power supply inhibition control if the cumulative number of times the protection circuit has operated exceeds 2000 times) For example, when the value of protection function activation counter (cumulative) 4b1, which indicates the cumulative number of times the protection circuit has activated, is greater than 2000, control unit 4a continues to prohibit power supply to deicer 3. In other words, when the cumulative number of times the protection circuit of IPD 4c has activated exceeds 2000, power supply to deicer 3 is completely stopped thereafter. In this case, if deicer 3 is to be used, heater module 4 needs to be replaced.

[0031] Incidentally, damage to the IPD is thought to accumulate due to the operation of the protection circuit. For example, the number of times the protection circuit operates is set to 100,000 times as the guaranteed number of times that the performance of the IPD can be ensured. Therefore, the threshold value of 2000 times in this embodiment is set, for example, as follows, with the idea of ​​ensuring the number of times the deicer 3 can be used for 10 years within the range in which the IPD does not break down. For example, if the number of times the deicer 3 is used per day is 2 times, and the number of operating days in a year is 83.75 days (= 365 days - 30 days) / 4, the number of times it is used in 10 years is 1675 times. A margin is added to this and the number is set to 2000 times. Note that, regarding the number of operating days in a year, 83.75 days, it is estimated that there are 30 days in a year when the vehicle is not used at all, and this amount is subtracted, and even on the days when the vehicle is used, the deicer 3 is not actually used for more than 1 / 4 of the time. Therefore, the number of times 2000 can be appropriately changed according to the expected usage conditions of the vehicle. This will prevent IPD4c failures while ensuring the use of Deaisa 3 for 10 years.

[0032] (Release of inhibition control when the protection circuit operates less than 10 times in one trip period) When the total number of times the protection circuit has been operated is less than 2000 times and the number of times the protection circuit has been operated in one trip period is less than 10 times (corresponding to "less than a predetermined value" in the present invention), the control unit 4a releases the power-on inhibition control (corresponding to "prohibition control" in the present invention) when the occupant turns off the deicer SW11 (corresponding to "predetermined opportunity" in the present invention) and returns to normal control for driving the deicer 3 (return to normal control: corresponding to "release control" in the present invention). Therefore, thereafter, when the occupant turns on the deicer SW11, the control unit 4a transmits a control signal (power-on request signal) to the IPD 4c, which sets the switch element of the IPD switch 4c to ON, thereby restarting power supply to the deicer 3. In this embodiment, the timing at which the control unit 4a releases the power-on inhibition control is when the occupant turns off the deicer SW11, but for example, the power-on inhibition control may be automatically released when a predetermined time has elapsed even if the deicer SW11 is not operated.

[0033] (Release of inhibition control when the protection circuit operates 10 or more times in one trip period) When the cumulative number of times the protection circuit has been activated is less than 2000 and the number of times the protection circuit has been activated in one trip period is 10 or more, the control unit 4a does not release the current inhibition control simply by the occupant turning OFF the deicer SW11, as in the case when the number of times the protection circuit has been activated is less than 10 (corresponding to "prohibition control" in the present invention). Specifically, the control unit 4a does not release the current inhibition control unless the IG switch 9 is set to OFF, and releases the current inhibition control when the occupant turns OFF the deicer SW11 after the IG switch 9 is set to OFF (return to normal control: corresponding to "release control" in the present invention).

[0034] The current inhibition control may be released when the IG switch 9 is set to OFF. For example, the current inhibition control may be released when the IG switch 9 is set to OFF even if the occupant does not turn the deicer switch 11 to OFF. Furthermore, the timing of releasing the current inhibition control may be, for example, that the control unit 4a releases the current inhibition control when the IG switch 9 is turned OFF, or that the control unit 4a releases the current inhibition control at a predetermined time between when the IG switch 9 is set to OFF and when the IG switch 9 is next set to ON. Furthermore, the control unit 4a may release the current inhibition control when the IG switch 9 is next set to ON after the IG switch 9 is set to OFF.

[0035] (Power supply control processing) Next, an example of the power supply control process to the desire in this embodiment will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a flowchart showing an example of the power supply control process to the desire executed by the heater module in Fig. 1, and Fig. 3 is a flowchart showing an example of the power supply control process to the desire executed by the heater module, which is a flowchart following Fig. 3. The power supply control process described below can also be applied to the PTC heater 2.

[0036] First, the control unit 4a transmits a control signal (power-off request signal) to the IPD 4c connected to the deicer 3 (step S1), and then determines whether or not the deicer SW11 has been turned on by the occupant (step S2). The control unit 4a continues to stop power supply to the deicer 3 until it determines in step S2 that the deicer SW11 has been turned on by the occupant (NO in step S2).

[0037] In step S2, if it is determined that the occupant has turned on the deicer SW11 (YES in step S2), the control unit 4a sends a control signal (power supply request signal) to the IPD 4c connected to the deicer 3, which sets the switch element of the IPD switch 4c to ON, thereby starting the supply of power to the deicer 3 (step S3).

[0038] Next, in step S4, if an overcurrent does not flow in the IPD 4c or the deicer 3 (including the wiring (harness) connecting the IPD 4c and the deicer) or if external noise is not superimposed on the current value, that is, a normal current-carrying state (NO in step S4), the control unit 4a acquires the current value supplied to the deicer 3 (step S5). The current value is output from the current sensor of the IPD 4c to the control unit 4a.

[0039] Next, the control unit 4a estimates the temperature of the wiring (harness) of the deicer 3 based on the acquired current value, and determines whether the estimated temperature is greater than an upper limit value, which is a temperature threshold value at which power supply to the deicer 3 is stopped (step S6). If the estimated temperature is equal to or less than the upper limit value (NO in step S6), the control unit 4a continues power supply to the deicer 3 until the occupant turns off the deicer SW11.

[0040] On the other hand, if it is determined that the estimated temperature is higher than the upper limit (YES in step S6), the control unit 4a transmits a control signal (power stop request signal) to the IPD 4c connected to the deicer 3, which sets the switch element of the IPD switch 4c to OFF, thereby stopping the power supply to the deicer 3 (step S7: power supply prohibition control). After performing the power supply prohibition control, the control unit 4a determines whether or not the deicer SW11 has been turned OFF by the occupant (step S8), and continues the power supply prohibition control to the deicer 3 until the OFF operation is performed.

[0041] When it is determined that the occupant has turned off the deicer SW11 during the current inhibition control (YES in step S8), the control unit 4a cancels the current inhibition control (returns to step S2). This causes normal current control of the deicer 3 to be performed, and when the occupant next turns on the deicer SW11 (YES in step S2), current control to the deicer 3 is resumed.

[0042] Returning to step S4, if an overcurrent flows through the IPD 4c or the deicer 3 (including the wiring (harness) connecting the IPD 4c and the deicer) or if external noise is superimposed on the current value, resulting in an abnormal current flow state to the deicer 3 (YES in step S4), the protection circuit of the IPD 4c is activated and the current flow to the deicer 3 is stopped (step S9). At this time, information indicating that the protection circuit has been activated in the IPD 4c is input to the control unit 4a. When the control unit 4a detects the activation of the protection circuit of the IPD 4c, the control unit 4a adds +1 to the value of the protection function activation counter (cumulative) 4b1 (step S10) and determines whether the value of the protection function activation counter (cumulative) 4b1 after the increment is greater than 2000 times. In other words, the control unit 4a determines whether the cumulative number of activations of the protection circuit of the IPD 4c exceeds 2000 times (step S11).

[0043] When it is determined that the cumulative number of times the protection circuit has been activated exceeds 2000 times (YES in step S11), the control unit 4a continues to prohibit the supply of electricity to the deicer 3 due to activation of the protection circuit of the IPD 4c, and ends the process (step S12). In other words, when the cumulative number of times the protection circuit has been activated exceeds 2000 times, there is no opportunity to release the prohibition on the supply of electricity to the deicer 3, and the supply of electricity to the deicer 3 is completely stopped.

[0044] In step S11, when it is determined that the cumulative number of times the protection circuit has been activated does not exceed 2000 times (NO in step S11), the control unit 4a increments the value of the protection function activation counter (1 trip) 4b2 by +1 (step S13), and determines whether the value of the protection function activation counter (1 trip) 4b2 after the increment is 10 times or more (step S14). When it is determined that the value of the protection function activation counter (1 trip) 4b2 is less than 10 times (NO in step S14), the control unit 4a determines whether the occupant has turned off the deicer SW11 (step S17), and waits until the OFF operation is performed (NO in step S17). That is, the control unit 4a continues the power supply control (prohibition control) to the deicer 3 that has been stopped due to the activation of the protection circuit of the IPD 4c until the occupant turns off the deicer SW11.

[0045] In step S17, when it is determined that the occupant has turned off the deicer SW11 (YES in step S17), the control unit 4a cancels the power prohibition control (returns to step S2). This causes normal power supply control to the deicer 3, and when the occupant next turns on the deicer SW11 (YES in step S2), power supply control to the deicer 3 is resumed (return to normal control).

[0046] When it is determined in step S14 that the value of the protection function activation counter (1 trip) 4b2 is 10 or more, the control unit 4a determines whether the IG switch 9 has been turned OFF by the occupant (step S15) and waits until it is turned OFF (NO in step S15). When it is determined that the IG switch 9 has been turned OFF by the occupant (YES in step S15), the control unit 4a clears the value of the protection function activation counter (1 trip) 4b2 to 0 (step S16).

[0047] Next, the control unit 4a determines whether or not the deicer switch 11 has been turned off by the passenger (step S17).

[0048] Here, when it is determined that the deicer switch 11 has not been turned off by the occupant (NO in step S17), the control unit 4a waits until the deicer switch 11 is turned off (NO in step S17).

[0049] In step S17, when it is determined that the occupant has turned off the deicer SW11 (YES in step S17), the control unit 4a cancels the power supply inhibition control (returns to step S2). This results in normal power supply control of the deicer 3, and when the occupant next turns on the deicer SW11 (YES in step S2), the power supply control to the deicer 3 is resumed (return to normal control: release control). In other words, when the value of the protection function activation number counter (1 trip) 4b2 is 10 times or more, the control unit 4a continues the power supply control (prohibition control) to the deicer 3 that was stopped due to the activation of the protection circuit of the IPD 4c after the IG switch 9 has been set to OFF (YES in step S15) until the occupant turns off the deicer SW11 (YES in step S17).

[0050] Therefore, according to the above embodiment, when the number of times the protection circuit of the IPD 4c is activated (the value of the protection function activation number counter (1 trip) 4b2) becomes 10 or more during the period from when the IG switch 9 is set to ON (the power supply of the vehicle is ON) until the ON setting is set to OFF (one trip period), the power supply control (prohibition control) to the deicer 3 that has been stopped by the activation of the protection circuit of the IPD 4c is not released until at least the IG switch 9 is set to OFF. Specifically, when the number of times the protection circuit of the IPD 4c is activated becomes 10 or more during one trip period, the power supply control (prohibition control) to the deicer 3 is not released until the deicer SW11 is turned OFF after the IG switch 9 is set to OFF (restriction on the release trigger of the power supply prohibition control). In this way, by making it difficult to easily return to normal control when the number of times the protection circuit of the IPD 4c is activated becomes 10 or more, the number of times (the number of retries) that the prohibition control to the deicer 3 and the release control are repeated during one trip period can be reduced. As a result, the accumulation of damage to the IPD 4c can be reduced, and failure of the IPD 4c can be prevented.

[0051] Furthermore, if the protection circuit of the IPD 4c operates less than 10 times in one trip period, the inhibition control of energization to the deicer 3 is released by the occupant turning OFF the deicer SW11. In this way, convenience in using the deicer 3 is ensured by releasing the inhibition control of energization by turning OFF the deicer SW11 until the protection circuit of the IPD 4c operates less than 10 times in one trip period.

[0052] Furthermore, when the protection circuit of the IPD 4c is activated and current to the deicer 3 is stopped, if the cause of the activation (e.g., overcurrent) is not removed, activation of the protection circuit and return to normal control will occur repeatedly. Here, in a configuration that allows easy return to normal control, an overcurrent flows through the wiring (harness) of the deicer 3 every time normal control is returned to, causing damage to the wiring (harness). However, in this embodiment, the number of times the protection circuit is activated in one trip period is limited to nine or less, so damage to the wiring (harness) caused by repeated returns to normal control can be reduced.

[0053] Furthermore, damage accumulates in the IPD 4c due to the operation of the protection circuit. Therefore, in this embodiment, when a certain amount of damage accumulates, such as when the cumulative number of times the protection circuit of the IPD 4c has been operated exceeds 2000 times, subsequent return to normal control is completely stopped (steps S11 and S12). In this manner, a failure of the IPD 4c can be prevented in advance, and for example, an ON failure in which the IPD 4c is always set to ON can be prevented in advance from causing a malfunction such as damage to the wiring (harness) of the deicer 3 due to heat.

[0054] Furthermore, since the prevention of failure of the above-mentioned IPD 4c and the reduction of damage to the wiring (harness) of the deicer 3 are performed by software, that is, by control by the control unit 4a, there is no need to modify the hardware, and the cost of the heater control device 1 can be reduced.

[0055] The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiments, the deicer 3 and the PTC heater 2 are described as examples of load circuits to which current is controlled by the heater module 4, but the present invention can also be applied to, for example, a seat heater disposed in a passenger seat to warm the seat, a steering heater to warm the steering wheel of a vehicle, and wiring (harness) connected to other devices.

[0056] In the above embodiment, the control unit 4a performs the power supply control, but part of the control may be performed by the control circuit of the IPD. For example, the control unit 4a may manage the temperature (temperature estimation) of the wiring (harness) of the load circuit, and the control circuit in the IPD may perform the power supply prohibition control and the release control when the estimated temperature reaches an upper limit, and the power supply prohibition control and the release control when the protection circuit is activated.

[0057] In the above embodiment, the switching element of the IPD 4c is configured as a FET. However, the present invention is not limited to this and may be configured as a semiconductor element such as a MOS-FET or an IGBT.

[0058] Furthermore, the present invention can be applied to any vehicle, including engine vehicles, electric vehicles, and hybrid vehicles.

[0059] Furthermore, the present invention can be adopted in various vehicle control devices that control the supply of electricity to a predetermined load circuit provided in a vehicle. [Explanation of symbols]

[0060] 1: Heater control device (vehicle control device) 2: PTC heater (load circuit) 3: De-icer (load circuit) 4a: Control unit (control means) 4c: IPD (semiconductor switching element)

Claims

[Claim 1] A semiconductor switching element capable of controlling current supply to a predetermined load circuit; a control unit that performs a prohibition control for prohibiting the semiconductor switching element from supplying current to the predetermined load circuit and a release control for releasing the prohibition control, The control means When an abnormality is detected in at least one of the predetermined load circuit and the semiconductor switching element, the prohibition control is performed. When an index value indicating the number of times the control means has performed the prohibition control during an on-continuation period, which is a period from when the power source of the vehicle is set to on until the power source is set to off, is less than a predetermined value, the release control is performed at a predetermined opportunity; When the index value during the on-continuation period is equal to or greater than the predetermined value, the release control is not performed at least until the power supply of the vehicle is set to off. A vehicle control device comprising:

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