JP2018014828A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device capable of making an execution time of heat degeneration control for suppressing an output current more than a target current value shorter.SOLUTION: A power supply device 1 includes a control part 10 for performing normal control for controlling an output current from a voltage conversion part 30 to a target current value on the basis of a current value detected by a current sensor 38 when temperature detected by a temperature sensor 31 is less than a predetermined temperature. The control part 10 performs heat degeneration control for making the output current outputted from the voltage conversion part 30 smaller than the target current value when a detection temperature of the temperature sensor 31 is equal to or more than the predetermined temperature and a detection value by an external state detection part is within a prescribed low fluid range. The control part performs control for making the output current from the voltage conversion part 30 larger than during execution of heat degeneration control when the detection temperature of the temperature sensor 31 is equal to or more than the predetermined temperature and the detection value by the external state detection part is within a prescribed high fluid range.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply device.

  It is known that a power supply device such as a DCDC converter generates heat due to internal power loss, and measures for preventing problems caused by temperature rise (destruction of internal circuits and the like) have been considered. For example, the control device for the DCDC converter disclosed in Patent Document 1 is configured to change the output current output from the DCDC converter based on the temperature of the DCDC converter, and the temperature of the DCDC converter is higher than a predetermined temperature. When it is low, control is performed to bring the output current of the DCDC converter closer to the target current value, and when it is higher than the predetermined temperature, control is performed to keep the output current lower than the target current value. It is configured to suppress temperature rise.

JP 2010-252512 A

  Control that suppresses the output current below the target current value (thermal degeneration control) when the temperature of the DCDC converter is high is control that limits the capability of the DCDC converter. It is desirable to shorten the length.

  However, since the control device of Patent Document 1 grasps only the temperature of the DCDC converter itself and switches between normal control and thermal degeneration control, the switching operation between normal control and thermal degeneration control is simple and rough. Thus, there is a problem that it is difficult to reduce the time during which the current is limited by the thermal degeneration control. For example, even if an external factor that contributes to shortening the time of the thermal degeneration control occurs outside the DCDC converter, the control device of Patent Document 1 cannot reflect the influence of the external factor, so the thermal degeneration control is performed. There is a tendency that the time to do it becomes long.

  The present invention has been made based on the above circumstances, and can perform thermal degeneration control that suppresses the output current below the target current value when the temperature rises, and the time during which the current is limited by the thermal degeneration control can be shortened. It is an object of the present invention to realize a power supply device that can be used.

The power supply device of the first invention is
A voltage converter that boosts or steps down the input voltage and outputs it;
A current detection unit for detecting a current value of an output current output from the voltage conversion unit;
A temperature detector for detecting the temperature of the voltage converter;
An external state detection unit that generates a detection value that reflects at least one of the degree of air flow outside the voltage conversion unit or the temperature outside the voltage conversion unit;
Normal control for controlling the output current output from the voltage conversion unit to a target current value based on the current value detected by the current detection unit when the temperature detected by the temperature detection unit is lower than a predetermined temperature The output current output from the voltage conversion unit when the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature and the detection value by the external state detection unit is in a predetermined first range is Thermal degeneration control is performed to make the current value smaller than the target current value, the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature, and the detection value by the external state detection unit is more effective in suppressing the temperature than the first range. A control unit that performs control to increase the output current from the voltage conversion unit when the thermal degeneration control is performed when it is within a large second range;
Have

The power supply device of the second invention is
A voltage converter that boosts or steps down the input voltage and outputs it;
A current detection unit for detecting a current value of an output current output from the voltage conversion unit;
A temperature detector for detecting the temperature of the voltage converter;
An external state detection unit that generates a detection value that reflects at least one of the degree of air flow outside the voltage conversion unit or the temperature outside the voltage conversion unit;
When the temperature detected by the temperature detection unit is lower than a predetermined temperature, the current value of the output current output from the voltage conversion unit is controlled to a target current value based on the current value detected by the current detection unit. Thermal degeneration control for performing normal control to reduce the current value of the output current output from the voltage conversion unit to be smaller than the target current value when at least the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature A control unit for performing
Have
The control unit performs current increase control to increase the output current output from the voltage conversion unit to the target current value when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, and the external control When the detection value of the state detection unit is the first setting range, the current in the current increase control is greater than when the detection value is the second setting range in which the temperature suppression effect is smaller than the first setting range. Increase the rate of increase.

In the power supply device of the first invention, the control unit outputs from the voltage conversion unit when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature and the detection value by the external state detection unit is within a predetermined first range. The thermal degeneration control is performed to make the output current to be smaller than the target current value. According to this configuration, when the temperature of the voltage conversion unit is relatively high and the temperature suppression effect from the outside of the voltage conversion unit is relatively small, the output current is suppressed by performing thermal degeneration control, and heat is generated. Can be reduced. Therefore, the temperature rise of the voltage conversion unit can be suppressed, and the voltage conversion unit and the like can be protected.
The control unit performs thermal degeneration control when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature and the detection value by the external state detection unit is within the second range where the temperature suppression effect is larger than the first range. Control is performed to increase the output current from the voltage converter more than the time. In this configuration, the thermal degeneration control is not performed uniformly when the temperature of the voltage conversion unit is relatively high, but the thermal degeneration control is performed when the temperature suppression effect from the outside of the voltage conversion unit is relatively large. Control to make the output current larger than at the time of execution. By such control, the time during which the current is limited by the thermal degeneration control can be further shortened. In addition, when the temperature suppression effect from the outside of the voltage conversion unit is relatively large, even if the output current is relatively large, the influence of heat generation caused by the current can be further mitigated by the temperature suppression effect from the outside. it can.
In particular, when the temperature of the voltage conversion unit is relatively high, when the temperature suppression effect from the outside is relatively small, protection of the voltage conversion unit and the like can be prioritized by performing thermal degeneration control. When the temperature suppression effect is relatively large, by increasing the output current, it is possible to relax the output limitation and prioritize the ability of the voltage converter.

In the power supply device of the second invention, the control unit makes the current value of the output current output from the voltage conversion unit smaller than the target current value when at least the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature. Perform thermal degeneration control. According to this configuration, when the temperature of the voltage conversion unit is relatively high, the output current can be suppressed and heat generation can be reduced by performing thermal degeneration control. Therefore, the temperature rise of the voltage conversion unit can be suppressed, and the voltage conversion unit and the like can be protected.
Further, the control unit performs current increase control for increasing the output current output from the voltage conversion unit to the target current value when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, and the external state detection unit When the detected value is the first set range, the current increase rate in the current increase control is made larger than when the detected value is the second set range where the temperature suppression effect is smaller than that of the first set range. In this configuration, when the execution condition of the normal control is satisfied when the thermal degeneration control is executed and the normal control is restored, the current increase rate is relatively increased in the first setting range where the temperature suppression effect is relatively large. It can be increased and increased to the target current value earlier. In particular, when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, if the temperature suppression effect from the outside of the voltage conversion unit is relatively large, the temperature of the voltage conversion unit is likely to be subsequently suppressed. Therefore, even if the target current value is increased earlier, a situation in which the thermal degeneration control must be executed immediately is unlikely to occur.

1 is a block diagram illustrating an in-vehicle system including a power supply device according to a first embodiment. It is a block diagram which shows more concretely a power supply device in the vehicle-mounted system of FIG. 3 is a flowchart illustrating switching control performed by the power supply device according to the first embodiment. It is a graph used as a reference in explaining the effect of the power supply device of Example 1, (A) is a graph about the case where current increase / decrease control is gently performed at the time of switching of severity, (B) is a graph of severity. It is a graph about the case where current increase / decrease control is performed sharply at the time of switching. It is a block diagram which shows more concretely a power supply device in the vehicle-mounted system of another Example.

Here, a desirable example of the present invention will be shown.
In the first invention, the control unit may perform normal control when the temperature detected by the temperature detection unit is equal to or higher than a predetermined temperature and the detection value by the external state detection unit is within the second range.

  As described above, even if the temperature of the voltage conversion unit is relatively high, if the normal control is performed when the temperature suppression effect from the outside of the voltage conversion unit is relatively large, the normal control is performed. It is possible to increase the amount of time that is displayed and to prioritize the performance of the voltage conversion unit.

  In the first invention, the control unit performs the current increase control for increasing the output current output from the voltage conversion unit to the target current value when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, and the external control When the detection value of the state detection unit is in the first setting range, the current increase rate in the current increase control is set larger than in the case where the detection value is in the second setting range where the temperature suppression effect is smaller than that in the first setting range. May be.

  In this configuration, when the execution condition of the normal control is satisfied when the thermal degeneration control is executed and the normal control is restored, the current increase rate is relatively increased in the first setting range where the temperature suppression effect is relatively large. It can be increased and increased to the target current value earlier. In particular, when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, if the temperature suppression effect from the outside of the voltage conversion unit is relatively large, the temperature of the voltage conversion unit is likely to be subsequently suppressed. Therefore, even if the target current value is increased earlier, a situation in which the thermal degeneration control must be executed immediately is unlikely to occur.

  In any of the inventions, the external state detection unit may include a wind speed sensor that detects, as a detection value, the wind speed of the arrangement space in which the power supply device is arranged or a space communicating with the arrangement space.

  The wind speed of the arrangement space where the power supply device is arranged or the space communicating with the arrangement space is a value reflecting the air flow state in this space, and the effect of suppressing the temperature of the voltage conversion unit as the wind speed of this space increases. Can be said to be large. Therefore, by providing a wind speed sensor that detects the wind speed in the space, it is possible to easily realize a configuration capable of grasping the degree of air flow outside the voltage converter, and to suppress the temperature from the outside of the voltage converter. Can be quantitatively detected.

  In any of the inventions, the external state detection unit may include a speed sensor that detects the speed of the vehicle on which the voltage conversion unit is mounted or the speed of the wheels of the vehicle as a detection value.

  The speed of the vehicle on which the voltage conversion unit is mounted or the speed of the wheels of the vehicle is a value that reflects the flow state of the air flowing into the vehicle. The larger the speed of the vehicle or the wheels of the vehicle, the higher the voltage of the flowing air. It can be said that the temperature suppression effect of the conversion part is great. Therefore, by providing the speed sensor, it is possible to easily realize a configuration capable of grasping the degree of air flow outside the voltage conversion unit, and how much the temperature suppression effect from the outside of the voltage conversion unit is. Can be detected quantitatively.

<Example 1>
Embodiment 1 of the present invention will be described below.
1 and 2 illustrate an in-vehicle system 100 including the power supply device 1 according to the first embodiment. A power supply device 1 shown in FIGS. 1 and 2 is configured as an in-vehicle power supply device mounted in a predetermined housing portion (engine room or the like) in a vehicle, for example. The power supply device 1 includes a control unit 10, a wind speed sensor 20, a voltage conversion unit 30, a temperature sensor 31, a voltage sensor 37, a current sensor 38, and the like.

  The voltage conversion unit 30 is configured as a DCDC converter that converts an input voltage by a switching operation of a switching element and outputs the converted voltage. In the following, an example in which the voltage conversion unit 30 is configured as a step-down converter will be described as a representative example, but the voltage conversion unit 30 may be a step-up converter. Further, the voltage conversion unit 30 may be a one-way or two-way step-up / step-down DCDC converter.

  The voltage conversion unit 30 is configured as a synchronous rectification non-insulated step-down switching regulator including, for example, MOSFETs 30A and 30B, a coil 30C, an input capacitor 30D, and an output capacitor 30E. In the voltage conversion unit 30, the on / off state of the high-side switching element (MOSFET 30A) and the on / off state of the low-side switching element (MOSFET 30B) are controlled by a PWM signal (control signal) from the control unit 10 described later. Thus, the input voltage applied to the first conductive path 32 is stepped down and output to the second conductive path 35.

  The voltage conversion unit 30 is electrically connected to the battery 33 via a first conductive path 32 that is a conductive path on the input side. The first conductive path 32 is electrically connected to a high potential side terminal of the battery 33, and a predetermined DC voltage is applied from the battery 33. The battery 33 is configured, for example, as a lead battery having an output voltage of about 14V when fully charged, and a DC voltage of about 14V is applied to the first conductive path 32 when the battery 33 is fully charged. The first conductive path 32 is connected to a load 34 and a generator (not shown). The load 34 may be any electrical component that can be operated by supplying power from the battery 33, and various on-vehicle electrical components are targeted.

  The voltage conversion unit 30 is electrically connected to the power storage unit 36 via a second conductive path 35 that is a conductive path on the output side. The second conductive path 35 is electrically connected to a high potential side terminal of the power storage unit 36, and a predetermined DC voltage is applied from the power storage unit 36. The power storage unit 36 is configured by a known power storage unit such as an electric double layer capacitor or a lithium ion battery, and the output voltage when fully charged is lower than the output voltage when fully charged.

  The voltage conversion unit 30 has a function of stepping down the voltage (input voltage) applied to the first conductive path 32 and outputting a desired output voltage to the second conductive path 35. Specifically, the control unit 10 complementarily outputs a PWM signal in a form in which a dead time is set for each gate of the high-side MOSFET 30A and the low-side MOSFET 30B of the voltage conversion unit 30. In the voltage conversion unit 30, when the first state in which the MOSFET 30A is turned on and the MOSFET 30B is turned off and the second state in which the MOSFET 30A is turned off and the MOSFET 30B is turned on are alternately switched, the first conductive path The DC voltage (input voltage) applied to 91 is stepped down, and an output voltage lower than the input voltage is output to the second conductive path 92. The output voltage output to the second conductive path 92 is determined according to the duty of the PWM signal applied to the gate of the switching element.

  The voltage sensor 37 is configured by a known voltage detection circuit, and outputs a value indicating the magnitude of the voltage of the second conductive path 35 as a detection value. The detection value of the voltage sensor 37 is input to the control unit 10, and the control unit 10 grasps the voltage value (output voltage value) Vout of the second conductive path 35 based on the detection value.

  The current sensor 38 is configured by a known current detection circuit, and has a function of detecting the current value of the output current output from the voltage conversion unit 30. The current sensor 38 outputs a value indicating the magnitude of the current flowing through the second conductive path 35 as a detection value, and the detection value from the current sensor 38 is input to the control unit 10. The control unit 10 grasps the current value (output current value) Iout of the second conductive path 35 based on the detection value input from the current sensor 38.

  The temperature sensor 31 corresponds to an example of a temperature detection unit and has a function of detecting the temperature of the voltage conversion unit 30. The temperature sensor 31 is mounted, for example, in the vicinity of the MOSFET 30A on the substrate on which the above-described MOSFETs 30A, 30B constituting the voltage conversion unit 30 are mounted. The temperature sensor 31 is configured by, for example, a thermistor, and outputs a detection value corresponding to the temperature of the switching element (eg, MOSFET 30A) of the voltage conversion unit 30. The control unit 10 grasps the temperature Tout of the voltage conversion unit 30 (specifically, the temperature of the switching element) from the detection value input from the temperature sensor 31.

  The control unit 10 is configured as a control circuit having an arithmetic function. As illustrated in FIG. 2, the control unit 10 includes a feedback control unit 11, a severity determination unit 12, a thermal degeneration control unit 13, and a signal generation unit 14. The control unit 10 can be configured by a microcomputer having an arithmetic device such as a CPU, a memory element such as ROM or RAM, and in this case, the feedback control unit 11, the severity judgment unit 12, the thermal degeneration control unit 13, The signal generation unit 14 is realized by a circuit in the microcomputer. Note that the control unit 10 may be configured by a hardware circuit.

  The wind speed sensor 20 corresponds to an example of an external state detection unit, and has a function of generating a detection value that reflects the degree of air flow outside the voltage conversion unit 30. Specifically, it has a function of detecting, as a detection value, the wind speed Wout at a position away from the voltage conversion unit 30 in the arrangement space in which the power supply device 1 is arranged. That is, it can be said that the greater the wind speed detected by the wind speed sensor 20, the greater the degree of air flow outside the voltage conversion unit 30 and the greater the temperature suppression effect of the voltage conversion unit 30. When the power supply device 1 is disposed in the engine room of the vehicle, the wind speed sensor 20 can be configured as a sensor that detects the wind speed at a predetermined position in the engine room. When the wind speed sensor 20 is arranged in an engine room in which air flows in and out through an open area provided on the lower side of the vehicle, the amount of air movement between the inside and outside of the engine room is large. The wind speed detected by the wind speed sensor 20 tends to increase, and the wind speed detected by the wind speed sensor 20 tends to increase as the vehicle speed of the vehicle increases.

  Here, the calculation of the duty performed by the feedback control unit 11 will be described.

  The feedback control unit 11 has a function of calculating a duty used during normal control. The feedback control unit 11 brings the current value output from the voltage conversion unit 30 to the second conductive path 35 close to the target current value Iref, and sets the voltage value output from the voltage conversion unit 30 to the second conductive path 35 as the target voltage value. A known feedback control is executed so as to approach Vref. The feedback control unit 11 includes a current feedback control unit 11A, a voltage feedback control unit 11B, and an arbitration unit 11C.

  The current feedback control unit 11A includes a current deviation calculation unit 11D and a calculation unit 11F. The current deviation calculator 11D calculates a deviation Di between the current value Iout detected by the current sensor 38 and the target value Iref of the output current. The target value Iref of the output current is stored in, for example, the memory of the power supply device 1 or an external device, and the calculation unit 11F performs voltage conversion by a known PID calculation method based on the deviation Di calculated by the current deviation calculation unit 11D. An operation amount (amount of increase / decrease in duty) for calculating the output current value Iout output from the unit 30 to be close to the target value Iref is calculated. The current target value Iref is a target value during normal control, and is, for example, a predetermined maximum current value. This target value Iref is different from the target value (limit current value) at the time of thermal degeneration control.

  The voltage feedback control unit 11B includes a voltage deviation calculation unit 11E and a calculation unit 11G. The voltage deviation calculator 11E calculates a deviation Di between the output voltage value Vout detected by the voltage sensor 37 and the output voltage target value Vref. The target value Vref of the output voltage is stored in the memory of the power supply device 1 or an external device, and the control unit 10 can acquire the target value Vref. Based on the deviation Dv calculated by the voltage deviation calculation unit 11E, the calculation unit 11G uses a known PID calculation method to control the operation amount (control for bringing the output voltage value Vout output from the voltage conversion unit 30 close to the target value Vref. The amount that increases or decreases the duty, which is an amount, is calculated.

  The arbitration unit 11C determines which of the operation amounts (amount to increase / decrease the duty) obtained by each of the current feedback control unit 11A and the voltage feedback control unit 11B is to be prioritized. As a determination method, for example, a method of giving priority to a small operation amount among the operation amounts generated by the calculation unit 11F and the calculation unit 11G can be considered. The determination method is not limited to this method, and other known methods may be used. The arbitration unit 11C calculates a new control amount (duty) by adding the priority operation amount among the operation amounts of the calculation unit 11F and the calculation unit 11G to the current control amount (duty). The control unit 10 repeatedly executes such feedback processing at a minute time interval, and calculates a control amount (duty) for each execution.

Next, functions of the severity determining unit 12 and the thermal degeneration control unit 13 will be described.
The severity determination unit 12 is a part that determines the degree of severity of the temperature environment outside the voltage conversion unit 30, and the severity is greater as the environment has a smaller temperature suppression effect on the voltage conversion unit 30. The more severe the temperature suppression effect on the voltage converter 30, the smaller the severity. In this configuration, the wind speed Wout detected by the wind speed sensor 20 is used as a value indicating the severity. The smaller the wind speed detected by the wind speed sensor 20, the greater the degree of severity, and the wind speed sensor 20 detects. The greater the wind speed, the smaller the severity.

  Specifically, when the wind speed Wout detected by the wind speed sensor 20 is equal to or lower than the first threshold value Wa (for example, 0.1 m / s), the severity determining unit 12 sets the severity to the first level. If the wind speed Wout detected by the wind speed sensor 20 is greater than the first threshold Wa and equal to or less than the second threshold Wb (1.0 m / s), the severity is at the second level. If it is determined as “medium” and the wind speed Wout detected by the wind speed sensor 20 is greater than the second threshold value Wb, the severity is determined to be “small” which is the third level. The first threshold value Wa and the second threshold value Wb have a relationship of Wa <Wb, and these values are stored, for example, in the memory of the power supply device 1 or the external device.

  The severity determining unit 12 makes such a determination every predetermined time, for example, and grasps the change state of the severity. Specifically, the severity changes from “Large” to “Large”, “Large” to “Medium”, “Large” to “Small”, “Middle” to “Large”, and “Middle” at a given time Whether “medium”, “medium” to “small”, “small” to “large”, “small” to “medium”, or “small” to “small” is determined. The determination result every predetermined time is updated every time a determination is made.

  The thermal degeneration control unit 13 restricts the value of the output current output from the voltage conversion unit 30 to the target value Iref and the value of the output current output from the voltage conversion unit 30 to a value smaller than the target value Iref. It has a function of switching between thermal degeneration control. Specifically, switching control (FIG. 3) described later is executed, and either normal control or thermal degeneration control is selected.

Here, switching control by the thermal degeneration control unit 13 will be described.
The thermal degeneration control unit 13 repeatedly executes the switching control shown in FIG. 3 every short time to determine a severity change pattern (step S1). The severity change state determined by the severity determining unit 12 is “small” to “large”, “medium” to “large”, “large” to “large”, “small” to “medium”, “medium”. If “from” to “medium”, the process of step S2 is executed. If it is “large” to “medium”, the process of step S5 is executed, from “large” to “small”, “medium”. In the case of “small” to “small” and “small” to “small”, the process of step S8 is executed.

  When executing the process of step S2, the thermal degeneration control unit 13 determines whether or not the detected temperature Tout of the temperature sensor 31 is higher than a predetermined temperature threshold Tth (for example, 130 ° C.). When the detected temperature Tout detected by the temperature sensor 31 is higher than the temperature threshold Tth, the process of step S3 is executed. When the detected temperature Tout is equal to or lower than the temperature threshold Tth, the process of step S4 is executed.

  The thermal degeneration control unit 13 performs thermal degeneration control as the process of step S3. The thermal degeneration control is a control that limits the output current value Iout from the voltage conversion unit 30 to be greater than the target current value Iref. Examples of the method of limiting the current by the thermal degeneration control include a method of gradually decreasing the output current value Iout of the voltage conversion unit 30 at a predetermined rate every unit time during the execution period of the thermal degeneration control. In this case, the output current value Iout is decreased at a constant rate of change (a predetermined rate for each unit time) over the period in which the process of step S3 or step S6 is executed. For example, every time the feedback calculation is executed, the duty at the previous feedback calculation is updated to a new duty so as to decrease the output current value Iout at a constant rate of change.

  In the method of limiting the current by the thermal degeneration control, the output current value Iout of the voltage conversion unit 30 is set to the difference between the temperature detected by the temperature sensor 31 and the predetermined target temperature every predetermined time over the execution period of the thermal degeneration control. It may be decreased at a corresponding rate. In this method, the rate of change (the rate at which the current is reduced) is updated every predetermined time, and the output current value Iout of the voltage conversion unit 30 is gradually reduced at a new rate of change every time it is updated. For example, every time feedback control is executed, the duty at the previous feedback calculation is updated to a new duty so as to decrease the output current value Iout at the updated rate of change.

  The thermal degeneration control unit 13 performs normal control as the process of step S4. While the execution of step S4 is continued, the output current value Iout is increased at the first increase rate during a period in which the difference between the output current value Iout from the voltage conversion unit 30 and the target current value Iref is a certain value or more. Continue to let. For example, every time the feedback calculation is executed, the duty at the previous feedback calculation is updated to a new duty so as to increase the output current value Iout at the first increase rate. When the difference between the output current value Iout and the target current value Iref is less than a certain value, the duty is determined to be determined by the feedback control unit 11. Thus, when normal control is performed in step S4, the duty is updated to increase the output current value Iout at the first increase rate until the output current value Iout approaches the target current value Iref to some extent, and the output current After the value Iout approaches the target current value Iref to some extent, the duty is updated by calculation of the feedback control unit 11.

  The thermal degeneration control unit 13 also determines whether or not the detected temperature Tout of the temperature sensor 31 is higher than a predetermined temperature threshold Tth (for example, 130 ° C.) even when executing the process of step S5. If the detected temperature Tout detected by the temperature sensor 31 is greater than the temperature threshold Tth, the process of step S6 is executed. If the detected temperature Tout is equal to or lower than the temperature threshold Tth, the process of step S7 is executed.

  The thermal degeneration control unit 13 performs thermal degeneration control as the process of step S6. The process of S6 is the same as the process of S3. For example, when the thermal degeneration control unit 13 uses a method of decreasing the output current value at a constant rate of change (a predetermined rate per unit time) over the period during which the process of S6 is being performed, the feedback calculation is performed. Every time, the duty of the previous feedback calculation is updated to a new duty so as to decrease the output current value at a constant rate of change. Note that the duty is updated so that the output current value of the voltage conversion unit 30 is decreased at a rate corresponding to the difference between the detected temperature Tout of the temperature sensor 31 and the predetermined target temperature over the execution period of the thermal degeneration control of S6. Also good.

  When the thermal degeneration control unit 13 executes normal control as the process of step S7, the difference between the output current value Iout from the voltage conversion unit 30 and the target current value Iref is large while the execution of step S7 is continued. During a period longer than a certain value, the output current value is continuously increased at the second increase rate. For example, every time the feedback calculation is executed, the duty at the previous feedback calculation is updated to a new duty so as to increase the output current value at the second increase rate. When the difference between the output current value Iout and the target current value Iref is less than a certain value, the duty is determined to be determined by the feedback control unit 11. Thus, when normal control is performed in step S7, the duty is updated to increase the output current value at the second increase rate until the output current value Iout approaches the target current value Iref to some extent, and the output current value After Iout approaches the target current value Iref to some extent, the duty is updated by the calculation of the feedback control unit 11. Further, the second increase rate is an increase rate larger than the first increase rate described above. That is, in S6, the rate of increasing the current is increased compared to the normal control executed in S4, and the output current value Iout is brought closer to the target current value Iref. When the severity changes from “large” to “medium”, it is predicted that the severity will further decrease thereafter. Therefore, the ratio of increasing the output current in step S7 increases the output current in step S4. It is larger than the ratio.

  When the thermal degeneration control unit 13 performs the normal control as the process of step S8, the difference between the output current value Iout from the voltage conversion unit 30 and the target current value Iref is large while the execution of step S8 is continued. During a period longer than a certain value, the output current value is continuously increased at the third increase rate. For example, every time the feedback calculation is executed, the duty at the previous feedback calculation is updated to a new duty so as to increase the output current value at the third increase rate. When the difference between the output current value Iout and the target current value Iref is less than a certain value, the duty is determined to be determined by the feedback control unit 11. Thus, when normal control is performed in step S8, the duty is updated to increase the output current value at the third increase rate until the output current value Iout approaches the target current value Iref to some extent, and the output current value After Iout approaches the target current value Iref to some extent, the duty is updated by the calculation of the feedback control unit 11. The third increase rate is an increase rate larger than the second increase rate described above. That is, in step S8, the ratio of increasing the current is further increased compared to the normal control executed in step S7, and the output current value Iout is brought closer to the target current value Iref. When the severity is “small”, the temperature suppression effect on the outside is very high, so the rate of increasing the output current in step S8 is even greater than the rate of increasing the output current in step S7. is there.

  In this way, the normal control or the thermal degeneration control is selected by the thermal degeneration control unit 13, and the duty is updated according to the selected control.

  The signal generation unit 14 generates a PWM signal with the duty set (updated) by the thermal degeneration control unit 13 and outputs the generated PWM signal in a complementary manner to each gate of the MOSFETs 30A and 30B shown in FIG.

  Thus, the control unit 10 is based on the current value Iout detected by the current sensor 38 (current detection unit) when the temperature Tout detected by the temperature sensor 31 (temperature detection unit) is lower than the predetermined temperature Tth. Then, normal control for controlling the output current output from the voltage converter 30 to the target current value Iref is performed. On the other hand, the control unit 10 heats the current value of the output current output from the voltage conversion unit 30 to be smaller than the target current value Iref on condition that at least the temperature Tout detected by the temperature sensor 31 is equal to or higher than the predetermined temperature Tth. Perform degeneration control. Specifically, when the temperature Tout detected by the temperature sensor 31 is equal to or higher than a predetermined temperature Tth and the detection value by the external state detection unit is within a predetermined first range (specifically, detected by the wind speed sensor 20). When the wind speed Wout is equal to or lower than Wb, that is, when the severity is “large” or “medium”, thermal degeneration control is performed in S4 or S7. Further, when the detection value by the external state detection unit is within the second range where the temperature suppression effect is larger than the first range (specifically, the wind speed Wout detected by the wind speed sensor 20 exceeds Wb, and the severity is “ When “small”, even if the temperature Tout detected by the temperature sensor 31 is equal to or higher than the predetermined temperature Tth, the output current from the voltage conversion unit 30 is made larger than when the thermal degeneration control is executed (specifically, Normal control).

  According to the power supply device 1 configured as described above, when the temperature of the voltage conversion unit 30 is relatively high and the temperature suppression effect from the outside of the voltage conversion unit 30 is relatively small, the thermal degeneration control is performed. By doing so, the output current can be suppressed and heat generation can be reduced. Therefore, the temperature rise of the voltage conversion unit 30 can be suppressed, and the voltage conversion unit 30 and the like can be protected.

  In addition, the control unit 10 of the power supply device 1 has a temperature suppression effect that is greater than the first range when the temperature Tout detected by the temperature sensor 31 (temperature detection unit) is equal to or higher than the predetermined temperature Tth and the detection value by the external state detection unit. Control in which the output current from the voltage conversion unit 30 is larger than when the thermal degeneration control is executed when it is within the large second range (when the wind speed Wout exceeds Wb and the severity is “low”). I do. In this configuration, thermal degeneration control is not performed uniformly when the temperature of the voltage conversion unit 30 is relatively high, but when the temperature suppression effect from the outside of the voltage conversion unit 30 is relatively large, thermal degeneration is performed. Control is performed to increase the output current compared to when control is executed. By such control, the time during which the current is limited by the thermal degeneration control can be further shortened. In addition, when the temperature suppression effect from the outside of the voltage conversion unit 30 is relatively large, even if the output current is relatively large, the influence of heat generation caused by the current can be further mitigated by the temperature suppression effect from the outside. Can do. In particular, when the temperature of the voltage conversion unit 30 is relatively high, when the temperature suppression effect from the outside is relatively small, it is possible to prioritize protection of the voltage conversion unit and the like by performing thermal degeneration control, and from the outside When the temperature suppression effect is relatively large, by increasing the output current, it is possible to relax the output limitation and prioritize the ability of the voltage converter.

  Further, the control unit 10 determines that the normal control execution condition is satisfied when the thermal degeneration control is executed (when the temperature Tout detected by the temperature sensor 31 is lower than the predetermined temperature Tth, or the severity is “low”. The current increase control for increasing the output current output from the voltage conversion unit 30 to the target current value Iref is performed to shift to the normal control. When the detection value of the external state detection unit is within the first setting range (specifically, when the wind speed Wout is greater than Wb), the control unit 10 determines the current increase rate in the current increase control as the detection value. Is higher than the current increase rate (first or second increase rate) when the temperature setting effect is lower than the first setting range (specifically, when the wind speed Wout is equal to or lower than Wb). A large third increase rate is assumed. In this configuration, when the execution condition of the normal control is satisfied when the thermal degeneration control is executed and the normal control is restored, the current increase rate is relatively increased in the first setting range where the temperature suppression effect is relatively large. It can be increased and increased to the target current value earlier. In particular, when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, if the temperature suppression effect from the outside of the voltage conversion unit is relatively large, the temperature of the voltage conversion unit is likely to be subsequently suppressed. Therefore, even if the target current value is increased earlier, a situation in which the thermal degeneration control must be executed immediately is unlikely to occur.

  Here, the effect of switching the output based on the severity of the environment outside the voltage converter (temperature severity) will be described with reference to simulation results. 4 (A) and 4 (B) are devices having the same hardware configuration as in FIG. 1, the output is limited when the severity is “large”, and the severity is “medium” or “small”. 4A is a simulation result in the case where the output current is returned to the target current value, and FIG. 4A shows the relative decrease in the current when moving to the thermal degeneration control and the increase when returning from the thermal degeneration control. It is a simulation result in the case of keeping it small. FIG. 4B is a simulation result when the degree of decrease in current when shifting to thermal degeneration control and the degree of increase when returning from thermal degeneration control are relatively increased.

  4A and 4B, the severity changes from medium or small to large at time T1, and after time T1, the current is suppressed by execution of thermal degeneration control, and the severity is reduced. It changes from large to medium or small at time T2, and after time T2, the output current value Iout is increased to the target current value Iref by releasing the thermal degeneration control. In the example of FIG. 4A, the output current value Iout is gradually decreased when the transition to the thermal degeneration control is performed after the time T1, and the output current value Iout is gradually decreased when the transition to the thermal degeneration control is performed after the time T2. It is rising. On the other hand, in the example of FIG. 4B, the output current value Iout is sharply reduced when the transition to the thermal degeneration control is performed after the time T1, and the output current value Iout is decreased when the transition to the thermal degeneration control is performed after the time T2. It is rising rapidly.

  In both the example of FIG. 4A and the example of FIG. 4B, when the severity changes to “large” at time T1, the start time for limiting the output current value Iout is the same, and both are the time T1. Output current value is limited. That is, even when the output current is rapidly decreased as shown in FIG. 4B, the time during which the output current value Iout is controlled to the target current value Iref cannot be increased. However, if the output current value Iout is sharply reduced as shown in FIG. 4B, the temperature suppression effect can be generated earlier.

  When the severity changes to “medium” or “small” at time T2, the method of gradually increasing the output current value Iout as shown in FIG. 4A until the output current value Iout reaches the target current value Iref. Takes a long time, and accordingly, the time during which the output current value Iout can be set to the target current value Iref is shortened. On the other hand, in the method of rapidly increasing the output current value Iout as shown in FIG. 4B, when the output current value Iout changes to “medium” or “small” at time T2, the output current value Iout more quickly reaches the target current value Iref. Will reach. Accordingly, the time during which the output current value Iout can be set to the target current value Iref is increased accordingly. Further, when the severity is lowered, even if the output current is rapidly increased as in the example of FIG. 4B, the temperature of the voltage conversion unit does not rapidly increase. In the example of FIG. 4B, the temperature is lower than the threshold temperature. Is suppressed. According to such simulation results, even when the degree of increase in the output current value is increased and the time to reach the target current value is shortened when the severity is low, the temperature of the voltage converter is not increased rapidly and stable. Can be confirmed. Since such an effect occurs when the severity is low, even if the current increase degree is relatively increased in the scenes of steps S7 and S8 in FIG. 4, the temperature increase of the voltage conversion unit 30 can be suppressed.

  The power supply device 1 includes a wind speed sensor 20 that detects, as an external value detection unit, a wind speed in an arrangement space (for example, a space in the engine room) in which the power supply device 1 is disposed as a detection value. The wind speed of the arrangement space in which the power supply device 1 is arranged is a value reflecting the air flow state in this space, and it can be said that the larger the wind speed in this space, the greater the effect of suppressing the temperature of the voltage conversion unit 30. Therefore, by providing the wind speed sensor 20 that detects the wind speed in the space, it is possible to easily realize a configuration that can grasp the degree of air flow outside the voltage conversion unit 30, and from the outside of the voltage conversion unit 30. It is possible to quantitatively detect how much the temperature suppression effect is.

<Other embodiments>
The present invention is not limited to the first embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the first embodiment, the power supply device is mounted in the engine room of a vehicle such as an automobile, but may be mounted in a place other than the engine room of the vehicle.
(2) Although the step-down DCDC converter is exemplified as the voltage conversion unit in the first embodiment, a step-up DCDC converter may be used. Further, it may be a buck-boost converter capable of performing a boosting operation and a boosting operation in one direction or in both directions.
(3) In Example 1, an electrical load is connected to the first conductive path, but an electrical load may be connected to the second conductive path.
(4) In the first embodiment, the values (wind speeds) Wa and Wb used for determining the severity are set to 0.1 m / s and 1.0 m / s, respectively. You may change it to a value.
(5) In Example 1, although 130 degreeC was illustrated as threshold value Tth which judges temperature Tout of the voltage conversion part 30, threshold value Tth may be values other than 130 degreeC.
(6) In the first embodiment, the wind speed sensor 20 configured as the external state detection unit generates a value reflecting the degree of air flow outside the voltage conversion unit 30, but the configuration is not limited to this configuration, and the voltage conversion unit A detection value reflecting the external temperature of 30 may be generated. For example, the temperature sensor is located at a position away from the voltage conversion unit 30 (a position that is spaced from the substrate on which the voltage conversion unit 30 is mounted, for example, a position separated from the power supply device 1 in the engine room). An external temperature sensor different from 31 may be provided to detect the temperature of the space outside the voltage converter 30. In this case, for example, the detection value (detection temperature) by the external temperature sensor can be a detection value reflecting the temperature outside the voltage conversion unit 30. In this case, for example, when the detected value (detected temperature) by the external temperature sensor is equal to or higher than the first temperature T1, the severity determining unit 12 determines that the severity is “high” and detects the detected value (detected temperature) by the external temperature sensor. ) Is less than the first temperature T1 and greater than or equal to the second temperature T2, it is determined that the severity is “medium”, and when the detected value (detection temperature) by the external temperature sensor is less than the second temperature T2, the severity is “small”. May be determined. However, T1> T2. In this example, the configuration and control can be the same as those in the first embodiment except for the method for determining the severity.
Further, when the external temperature sensor for detecting the temperature of the space around the power supply device 1 is provided as described above, the method of determining the severity may be changed, and the wind speed detected by the wind speed sensor 20 and the external temperature sensor are detected. Severity may be determined based on the temperature (temperature outside the voltage conversion unit 30). For example, when the wind speed Wout detected by the wind speed sensor 20 is less than the predetermined wind speed threshold Wc and the temperature detected by the external temperature sensor is equal to or higher than the predetermined temperature threshold Tc, it is determined that the severity is “high”, and the wind speed When the wind speed Wout detected by the sensor 20 is equal to or higher than the predetermined wind speed threshold Wc or the temperature detected by the external temperature sensor is lower than the predetermined temperature threshold Tc, it is determined that the severity is “medium” and is detected by the wind speed sensor 20. When the wind speed Wout is equal to or higher than the predetermined wind speed threshold Wc and the temperature detected by the external temperature sensor is lower than the predetermined temperature threshold Tc, it may be determined that the severity is “low”. Also in this example, the same configuration and control as in the first embodiment can be used except for the method of determining the severity.
(7) In the first embodiment, the severity is determined to be three states of large, medium, and small. However, the present invention is not limited to this, and the severity may be determined to be two states. It may be determined. In either example, the severity of thermal degeneration control is executed when the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature, and the thermal degeneration control is performed when the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature. It is only necessary to set a severity with which control for increasing the output current is executed.
(8) In the first embodiment, when returning to normal control, the degree of increase (increase speed) in which the output current is increased in step S7 is made larger than the degree of increase (increase speed) in which the output current is increased in step S4. However, these may be the same.
(9) In the first embodiment, when returning to the normal control, the degree of increase (increase speed) for increasing the output current in step S8 is set larger than the degree of increase (increase speed) for increasing the output current in step S7. However, these may be the same.
(10) In Example 1, although the wind speed sensor 20 was arrange | positioned in the arrangement space (for example, space in an engine room) of the voltage conversion part 30, the example which detects the wind speed of the arrangement space was shown, It may be arranged in a space communicating with the arrangement space of the voltage conversion unit 30 in the vehicle, and the wind speed in this communication space is detected as a detection value (a value reflecting the degree of air flow outside the voltage conversion unit 30). May be.
(11) In the first embodiment, the wind speed is generated as the detection value as a value reflecting the degree of air flow outside the voltage conversion unit 30. However, as shown in FIG. You may provide the speed sensor 220 which detects the vehicle speed or wheel speed of the vehicle mounted. In this case, the speed sensor 220 generates the vehicle speed or the wheel speed as a detection value as a value reflecting the degree of air flow outside the voltage conversion unit 30. In this case, for example, when the detected value (vehicle speed or wheel speed) V detected by the speed sensor 220 is less than the first speed V1, the severity determining unit 12 determines that the severity is “high” and detects the detected value (vehicle speed or wheel speed). Speed) is greater than or equal to the first speed V1 and less than the second speed V2, it is determined that the severity is “medium”, and when the detected value (vehicle speed or wheel speed) is greater than or equal to the second speed V2, the severity is “small”. It can be judged. However, V2> V1. In this example, the configuration and control can be the same as those in the first embodiment except for the method for determining the severity.
The speed of the vehicle on which the voltage conversion unit 30 is mounted or the speed of the wheels of the vehicle is a value that reflects the flow state of the air flowing into the vehicle, and the greater the speed of the vehicle or the wheels of the vehicle, It can be said that the temperature suppression effect of the voltage converter 30 is large. Therefore, by providing the speed sensor 220, it is possible to easily realize a configuration capable of grasping the degree of air flow outside the voltage conversion unit 30, and to what extent is the temperature suppression effect from the outside of the voltage conversion unit 30? Can be quantitatively detected.
(12) In the description of the first embodiment, even when the temperature Tout detected by the temperature sensor 31 is equal to or higher than the predetermined temperature Tth, the detected value by the external state detection unit is within the second range (for example, by the wind speed sensor 20). In the case where the detected wind speed Wout is Wb or more and the severity is “low”, the configuration in which the normal control is performed in step S8 is illustrated. However, it is not limited to this example. For example, when the severity is “low” and the temperature Tout detected by the temperature sensor 31 is equal to or higher than a predetermined temperature Tth, the output current value from the voltage conversion unit 30 is smaller than that during normal control and You may control to a larger electric current value than the time of thermal degeneration control.

DESCRIPTION OF SYMBOLS 1 ... Power supply device 10 ... Control part 20 ... Wind speed sensor (external state detection part)
30 ... Voltage converter 31 ... Temperature sensor (temperature detector)
38 ... Current sensor (current detector)
220 ... Speed sensor (external state detector)

Claims (6)

A voltage converter that boosts or steps down the input voltage and outputs it;
A current detection unit for detecting a current value of an output current output from the voltage conversion unit;
A temperature detector for detecting the temperature of the voltage converter;
An external state detection unit that generates a detection value that reflects at least one of the degree of air flow outside the voltage conversion unit or the temperature outside the voltage conversion unit;
Normal control for controlling the output current output from the voltage conversion unit to a target current value based on the current value detected by the current detection unit when the temperature detected by the temperature detection unit is lower than a predetermined temperature The output current output from the voltage conversion unit when the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature and the detection value by the external state detection unit is in a predetermined first range is Thermal degeneration control is performed to make the current value smaller than the target current value, the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature, and the detection value by the external state detection unit is more effective in suppressing the temperature than the first range. A control unit that performs control to increase the output current from the voltage conversion unit when the thermal degeneration control is performed when it is within a large second range;
A power supply device having   2. The control unit according to claim 1, wherein the control unit performs the normal control when a temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature and the detection value by the external state detection unit is within the second range. The power supply described.   The control unit performs current increase control to increase the output current output from the voltage conversion unit to the target current value when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, and the external control When the detection value of the state detection unit is the first setting range, the current in the current increase control is greater than when the detection value is the second setting range in which the temperature suppression effect is smaller than the first setting range. The power supply device according to claim 1, wherein the increase rate is increased. A voltage converter that boosts or steps down the input voltage and outputs it;
A current detection unit for detecting a current value of an output current output from the voltage conversion unit;
A temperature detector for detecting the temperature of the voltage converter;
An external state detection unit that generates a detection value that reflects at least one of the degree of air flow outside the voltage conversion unit or the temperature outside the voltage conversion unit;
When the temperature detected by the temperature detection unit is lower than a predetermined temperature, the current value of the output current output from the voltage conversion unit is controlled to a target current value based on the current value detected by the current detection unit. Thermal degeneration control for performing normal control to reduce the current value of the output current output from the voltage conversion unit to be smaller than the target current value when at least the temperature detected by the temperature detection unit is equal to or higher than the predetermined temperature A control unit for performing
Have
The control unit performs current increase control to increase the output current output from the voltage conversion unit to the target current value when the execution condition of the normal control is satisfied when the thermal degeneration control is performed, and the external control When the detection value of the state detection unit is the first setting range, the current in the current increase control is greater than when the detection value is the second setting range in which the temperature suppression effect is smaller than the first setting range. A power supply that increases the rate of increase.   The said external state detection part has a wind speed sensor which detects the wind speed of the space where the said power supply device is arrange | positioned, or the space connected to the said arrangement space as said detection value. The power supply described.   The said external state detection part has a speed sensor which detects the speed of the vehicle in which the said voltage conversion part is mounted, or the speed of the wheel of the said vehicle as said detection value. Power supply.

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