JP2010089588A - Vehicular power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular power supply capable of quickly returning an electric load to a state before restriction when the supply of power to the PWM controlled electric load is restricted or cancelled. <P>SOLUTION: When a current value supplied to an EPS driver is "Ia" or more, the start of the EPS driver is detected and the power to be supplied to a heater is restricted. When the current value is "Ib" or less which is smaller than the "Ia", the restriction is cancelled. Further, since the restriction is cancelled until the total amount of OFF time in each control period of the PWM control becomes not less than the total amount of ON time reduced by the restriction, the direct-current power is supplied from an on-vehicle power source to the heater. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vehicle power supply device that temporarily limits power supplied to an electric load by PWM control.

  In a vehicle power supply device, power is supplied to many electric loads such as a power window, an EPS (electric power steering device), an air conditioner, a defogger, and a seat heater. Among these electric loads, for example, in a power window, EPS, air conditioner, etc., an inrush current is generated at the time of starting, and the load current of the vehicular power supply apparatus greatly fluctuates.

  On the other hand, a technique has been devised to stop or limit the supply of electric power to some electric loads when preparing for the generation of an inrush current or when an inrush current occurs. In addition, when an inrush current actually occurs, the capacity of the current supplied to the electric load may be limited in order to prevent the operation of the electric load from becoming unstable due to a drop in the power supply voltage. . This capacity limitation is often implemented also for the purpose of arbitrarily controlling the power supplied to the electric load.

For example, in Patent Document 1, the terminal voltage and load current of an in-vehicle power supply are measured as needed, the terminal voltage that drops with the operation of an electrical load that is an important safety system is predicted, and based on the predicted terminal voltage, A technique for limiting a current supplied to an electrical load that is not a safety system is disclosed.
JP 2007-8214 A

  However, when the restriction is released after restricting the supply of power to the electric load whose current is restricted, while the supply is restricted, for example, the temperature of the heater is lowered and the electrical resistance is reduced. The state of the electric load has changed, and it may take a long time to return to the original state after the restriction is released.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a state before the electric load is restricted when the supply of electric power to the electric load under PWM control is restricted / released. Another object of the present invention is to provide a vehicular power supply device that can be quickly restored.

  The vehicle power supply device according to the first aspect of the invention includes means for PWM-controlling the power supplied from the in-vehicle power source to the first load, and activation detecting means for detecting the activation of the second load to be supplied with power from the in-vehicle power source. When the activation detection means detects activation, the vehicle power supply apparatus includes a control means for restricting the supply of power by the PWM control and releasing the restriction after the restriction. The power is continuously supplied from the release to an appropriate time point.

In this vehicular power supply device, for example, when PWM control of power supplied to the first load is limited in order to avoid temporal overlap with the starting current supplied to the second load, the limitation is released. Electric power is continuously supplied from the in-vehicle power source to the first load under appropriate conditions.
As a result, the amount of power that should have been supplied to the first load while the supply of power is restricted is quickly compensated by an appropriate amount while the power is continuously supplied to the first load.

  The vehicular power supply device according to a second aspect of the present invention is characterized in that the control means does not supply the power when the restriction is imposed.

In this vehicular power supply device, when the supply of electric power by PWM control is restricted, no electric power is supplied, in other words, the supplied electric power is cut off 100%.
Thereby, the electric power to be supplied to the first load while being limited is directed to the second load to the maximum extent.

  According to a third aspect of the present invention, there is provided a vehicular power supply apparatus according to the first aspect of the present invention, wherein the on-time of each control cycle of the PWM control calculates a total amount of on-time reduced by the restriction, and the control means releases the restriction. Second calculation means for calculating a total amount of off-time for each control cycle after the first calculation means, and the total amount of off-time calculated by the second calculation means is reduced by the first calculation means. The control means is configured to continuously supply the electric power until the total amount becomes equal to or greater than the total amount.

In this vehicle power supply device, from when the restriction on the power supplied to the first load is released, until the total amount of off time in each control cycle of PWM control becomes equal to or greater than the total amount of on time reduced by the restriction The electric power is continuously supplied from the in-vehicle power source to the first load.
As a result, when there is no change in the voltage of the in-vehicle power source and the impedance of the first load before and after the restriction on the supply of power to the first load, the first load is supplied while the power supply is restricted The amount of power that should have been supplied is supplemented by an equal amount while continuously supplying power to the first load.
Therefore, state fluctuations such as a decrease in the temperature of the heater and a decrease in the number of rotations of the motor that occur in the first load while the supply of power is restricted are quickly canceled while the power is continuously supplied. Can be.

  The vehicle power supply device according to a fourth aspect of the present invention comprises means for determining whether or not the total amount of reduced on-time calculated by the first calculation means is greater than or equal to a predetermined time, and said means has determined that In this case, the control unit is configured to continuously supply the power until the total amount of off time calculated by the second calculation unit becomes equal to or greater than the predetermined time.

In this vehicular power supply device, when the total amount of on-time reduced is equal to or greater than a predetermined time, the on-vehicle power source continues to the first load until the total amount of off-time in each control cycle of PWM control is equal to or greater than the predetermined time. Power is supplied.
Thereby, when the state fluctuation of the first load due to the limitation of the power supply is saturated, an upper limit is set for the time during which the power is continuously supplied. Accordingly, it is possible to prevent excessive power from being supplied past the amount necessary for canceling the state variation of the first load while continuously supplying power.

  The vehicular power supply device according to a fifth aspect of the present invention comprises first time measuring means for measuring the time for which the control means has caused the restriction, and the first calculation means is configured such that the first time measuring means measures the time The duty ratio of the PWM control before the limit is imposed and the ratio of the duty ratio reduced due to the restriction being multiplied are calculated to calculate the total amount of on-time reduced. Features.

In this vehicle power supply device, the duty ratio of the PWM control before the restriction is made and the ratio of the duty ratio reduced by the restriction during the time when the supply of power to the first load is restricted To calculate the total amount of reduced on-time.
Thereby, it is not necessary to integrate the reduced time for each control pulse of PWM control, and the total amount of the reduced on-time can be easily acquired with a small error.

  The vehicular power supply device according to a sixth aspect of the present invention comprises second timing means for starting timing when the control means releases the restriction, and the second calculation means is the time counted by the second timing means. From this, the total amount of off time is calculated by subtracting the product of the time and the duty ratio of the PWM control.

In this vehicle power supply device, the off time is reduced by subtracting the product of the time and the duty ratio of the PWM control from the time measured starting from when the restriction on the supply of power to the first load is released. Calculate the total amount.
As a result, it is not necessary to integrate the off time for each control pulse of the PWM control, and the total amount of off time can be easily acquired with a small error.

  According to a seventh aspect of the present invention, there is provided a vehicular power supply apparatus, wherein the on-time of each control cycle of the PWM control is calculated by calculating a total amount of on-time reduced by the limitation, and the respective amounts are calculated from the total amount calculated by the calculation unit. Subtracting means for sequentially subtracting the OFF time of the control cycle, and the control means continuously supplies power until the subtraction result calculated by the subtracting means becomes 0 or less. .

In this vehicle power supply device, from the on-vehicle power supply until the result of sequentially subtracting the off time of each control cycle of the PWM control from the total amount of on time reduced by the restriction of the power supplied to the first load becomes 0 or less. Electric power is continuously supplied to the first load.
As a result, when there is no change in the voltage of the in-vehicle power source and the impedance of the first load before and after the restriction on the supply of power to the first load, the first load is supplied while the power supply is restricted. The amount of power that should have been supplied is supplemented by an equal amount while continuously supplying power to the first load.
Therefore, state fluctuations such as a decrease in temperature and a decrease in rotation speed that occur in the first load while the supply of power is restricted are quickly canceled out while the power is continuously supplied. Can do.

  The vehicular power supply device according to an eighth aspect of the present invention comprises means for determining whether or not the total amount of reduced on-time calculated by the calculation means is a predetermined time or more, and when the means determines that The subtracting means sequentially subtracts the off time of each control period from the predetermined time.

In this vehicular power supply device, when the total amount of the reduced on-time is equal to or greater than a predetermined time, the on-vehicle power supply is used until the result of sequentially subtracting the off-time of each control cycle of the PWM control from the predetermined time becomes 0 or less Electric power is continuously supplied to the first load.
Thereby, when the state fluctuation of the first load due to the limitation of the power supply is saturated, an upper limit is set for the time during which the power is continuously supplied. Accordingly, it is possible to prevent excessive power from being supplied past the amount necessary for canceling the state variation of the first load while continuously supplying power.

  A vehicular power supply device according to a ninth aspect of the invention comprises first load current detection means for detecting a current value supplied to the first load, and the current value detected by the first load current detection means is equal to or less than a predetermined threshold value. Until this time, the control means is configured to supply power continuously.

In this vehicle power supply device, power is continuously supplied from the in-vehicle power supply to the first load until the current value supplied to the first load becomes equal to or less than a predetermined threshold value.
Thus, for example, while the supply of electric power to the motor or heater is restricted, the load current that has been decreased and increased while the rotation speed or temperature is increased while the electric power is continuously supplied. Decrease quickly to the current value.

  A vehicular power supply device according to a tenth aspect of the present invention comprises means for storing a current value detected by the first load current detecting means before the control means causes the restriction, and the current value stored by the means is It is characterized by being a predetermined threshold value.

In this vehicle power supply device, the current value supplied to the first load is detected and stored before limiting the supply of power to the first load, and the stored content is set as the predetermined threshold.
Thereby, for example, while the supply of electric power to the motor or the heater is restricted, the supply of electric power is performed while the electric power is continuously supplied to the load current that is increased by decreasing the rotation speed or the temperature. Decrease quickly to the current value before the limit.

  A vehicle power supply device according to an eleventh aspect of the invention comprises second load current detection means for detecting a current value supplied from the in-vehicle power supply to the second load, and the current value detected by the second load current detection means is the first value. When it is equal to or greater than a threshold value, the activation detection means detects activation.

  In this vehicle power supply device, in order to detect the start of the second load when the current value supplied to the second load becomes equal to or greater than the first threshold, the first load follows the increase in the load current of the second load. Start limiting the supply of power to.

  In a vehicle power supply device according to a twelfth aspect of the present invention, when the current value detected by the second load current detection means is equal to or less than a second threshold value that is smaller than the first threshold value, the control means releases the restriction. It is characterized by being.

  In this vehicular power supply device, when the load current value of the second load becomes equal to or smaller than the second threshold value which is smaller than the first threshold value, the restriction start is started in order to cancel the restriction on the supply of power to the first load. And hysteresis occurs in the transition of release. Therefore, the influence of noise included in the load current of the second load is suppressed.

A power supply device for a vehicle according to a thirteenth aspect includes power supply detection means for detecting the start of power supply to the second load,
When the power supply detection means detects the start, the activation detection means detects the activation.

  In this vehicle power supply device, since the activation of the second load is detected when the supply of power to the second load is turned on, the power to the first load is increased before the load current to the second load actually increases. Start restricting supply. Therefore, it is suppressed that the starting performance of the second load is impaired.

  A power supply device for a vehicle according to a fourteenth aspect of the present invention comprises means for starting timing when the power supply detecting means detects start, and when the means counts a predetermined time, the control means restricts the restriction. It is made to cancel.

  In this vehicular power supply device, the restriction on the supply of electric power to the first load is released after a predetermined time from when the supply of electric power to the second load is turned on. The supply of power to the first load is continuously limited for a predetermined time so as not to impair the load starting performance.

According to the present invention, power is continuously supplied to the first load under appropriate conditions after the restriction on the supply of power to the first load is released.
As a result, the amount of power that should have been supplied to the first load while the supply of power is restricted is quickly compensated by an appropriate amount while the power is continuously supplied to the first load. Therefore, when the supply of electric power to the electric load that is PWM-controlled is restricted / released, the electric load can be quickly returned to the state before the restriction.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of a vehicle power supply device according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes an alternator (an on-vehicle generator or an AC generator) that generates power in conjunction with the engine. The alternator 1 adjusts the field current of the alternator 1 to determine the voltage generated and rectified by the alternator 1. A regulator 2 for voltage control and step-up / step-down control is attached.

  The vehicle power supply device includes a relay box 6 having a plurality of fuses, and the electric power generated by the alternator 1 is given to the in-vehicle battery 4 whose input / output current value is detected by the current detector 3 through the fuse F0. The output of the current detector 3 is connected to a charge control ECU 5 having voltage detection means 51 for detecting the input / output voltage value of the in-vehicle battery 4. The output voltage of the in-vehicle battery 4 is applied through the fuse F1 to the EPS drive circuit 8 that drives the motor 7 of the EPS (electric power steering device) according to the operation force of the handle detected by a torque detector (not shown). The load is also applied through each fuse.

  The relay box 6 also includes an FET (field effect transistor) 61 for applying the output voltage of the in-vehicle battery 4 to the heater (heater) Ha through the fuse F2, and a controller 62 for controlling on / off of the FET 61. Have The central part of the control unit 62 is a CPU 621. The CPU 621 includes a ROM 622 for storing information such as programs, a RAM 623 for storing temporarily generated information, a timer 624 for measuring time, and an input / output port (I / O port). ) 625a, 625b, 625c, 625d are mutually connected by bus.

  The output terminal of the input / output port 625a is connected to the gate of the FET 61. The detection value of the current detector 9 that detects the current value supplied to the EPS drive circuit 8 is given to the input terminal of the input / output port 625b, and the ON / OFF signal of the switch SW1 of the heater Ha is input to the input / output port 625c. Given to the terminal. The detection value of the current detector 10 for detecting the current value supplied to the heater Ha is given to the input terminal of the input / output port 625d.

  Based on the given vehicle speed value, the charging control ECU 5 determines each vehicle state of idling, acceleration traveling, steady traveling, and deceleration traveling, and power generation is performed in a power generation mode corresponding to the determined vehicle state. In addition, charge control for controlling the alternator 1 and the regulator 2 is performed. The power generation mode is set so as to increase the power generation voltage when the engine load is large as in acceleration running. This reduces the load on the engine and improves the fuel efficiency of the vehicle.

The CPU 621 of the control unit 62 executes processes such as input / output and calculation according to a control program stored in advance in the ROM 622. More specifically, the CPU 621 turns on the heater Ha by turning on / off the gate of the FET 61 via the input / output port 625a during the period when the ON signal of the switch SW1 is given via the input / output port 625c. The voltage to be applied is PWM controlled. Further, the CPU 621 takes in the detection value of the current detector 9 through the input / output port 625b.
In another embodiment to be described later, when performing control based on the current value supplied to the heater Ha, the CPU 621 takes in the detection value of the current detector 10 via the input / output port 625d.

  2 and 3 are timing charts schematically showing how the temperature of the heater Ha changes when the power supplied to the heater Ha is limited when the activation of the EPS drive circuit 8 is detected. In the figure, the horizontal axis indicates time. 2A and 3A show changes in the load current to the EPS drive circuit 8, and the vertical axis shows the current value. In FIG. 2B and FIG. 3B, the solid line represents the load current to the heater Ha, and the broken line represents the current that is not actually supplied to the heater Ha. The vertical axis indicates the current value. 2C and 3C show the temperature change of the heater Ha, and the case where the present invention is applied is indicated by a solid line, and the case where the present invention is not applied is indicated by a one-dot chain line. The vertical axis shows the relative temperature. Note that the alternate long and short dash line schematically shows the center line of the temperature change.

2 and 3, when the current supplied to the heater Ha is not limited and when the heater Ha is not energized continuously, as shown in FIGS. 2B and 3B, the heater Ha is supplied. The supplied current is PWM-controlled, and the temperature of the heater Ha changes between high and low according to on / off of the current supplied to the heater Ha, as shown in FIGS. 2 (c) and 3 (c). .
2A and 3A, when the load current to the EPS drive circuit 8 becomes equal to or greater than the current value Ia (first threshold), the activation of the EPS drive circuit 8 is detected and supplied to the heater Ha. Start limiting current. The time limit for limiting the current supplied to the heater Ha is continued until the load current to the EPS drive circuit 8 becomes equal to or smaller than the current value Ib (second threshold value) smaller than the current value Ia, and the off-delay time elapses.
The time delay may not include the off delay time.

The current supplied to the heater Ha within the time limit may be cut off 100% as shown by the broken line in FIG. 2B, and the ON time of the control pulse is set as shown by the solid line and the broken line in FIG. You may make it supply partially restrict | limited. In FIG. 3C of the first embodiment, the ON time of the control pulse is limited by 50%.
When 100% of the current supplied to the heater Ha is cut off, the temperature of the heater Ha falls while drawing a gentle curve as shown in FIG. Further, when the on-time of the control pulse is limited by 50%, the temperature of the heater Ha decreases with a partial increase as shown in FIG.

  Thereafter, when the time limit ends, continuous energization to the heater Ha is started. The continuous energization time is until the total value of the current conduction time that should have been supplied to the heater Ha during the time limit reaches the total value of the non-energization time corresponding to the off time of the control pulse. Let it continue. Therefore, in FIG. 2B and FIG. 3B, the total value of the ON time of the control pulse indicated by the broken line during the time limit is equal to the OFF time of the control pulse during the continuous energization time (the original value indicated by the broken line). Control is made to be substantially equal to the total value of the time excluding the on-time.

  By continuously energizing the heater Ha in this manner, the temperature of the heater Ha that has fallen during the time limit rises rapidly as shown in FIGS. 2 (c) and 3 (c). This is because, when the present invention is not applied, in other words, when continuous energization is not performed, the temperature of the heater Ha only rises gently as shown by the one-dot chain line in FIGS. 2 (c) and 3 (c). Is in contrast.

FIG. 4 is a flowchart showing a processing procedure of the CPU 621 for restricting / releasing the supply of current to the heater Ha. The following processing is executed as needed according to a control program stored in the ROM 622 in advance.
“Ia”, “Ib” and “off delay” are known constants. The “energization state”, “limit counter”, “delay counter”, “reduction on time”, “duty ratio”, “limit rate”, “energization counter”, “integrated off time”, and “PWM state” are stored in the RAM 623. It is assumed that “I” is a temporary variable stored in the register of the CPU 621. “(Variable)” indicates the contents of “Variable” (the same applies hereinafter).

  Among the variables described above, variables with names “counter” and “time” represent a time that is an integral multiple of the unit time described below. The “duty ratio” and “PWM state” are set in the process related to PWM control described later, and the initial value of “energization state” is set to “PWM”. And Further, the “limit rate” is a value that is set separately according to the load status at that time, and may be stored in the ROM 622 as a constant.

  The CPU 621 fetches the detection value of the current detector 9 via the input / output port 625b, that is, the current value supplied to the EPS drive circuit 8 (step S11), and whether the fetched current value (I) is “Ia” or more. It is determined whether or not (step S12). When it determines with it not being more than "Ia" (step S12: NO), CPU621 returns a process to step S11.

When it is determined that it is equal to or greater than “Ia” (step S12: YES), the CPU 621 detects the activation of the EPS drive circuit 8 and substitutes (stores) “restriction” for “energized state” (step S13). The gate of the FET 61 is turned off via the output port 625a (step S14). At this time, the current supplied to the heater Ha is limited. Thereafter, the CPU 621 assigns an initial value “0” to the “limit counter” that counts the limit time for limiting the current supply (step S15), and the constant “off delay” to the “delay counter” that counts the off-delay time. Is substituted (step S16).
The “energized state” is a variable referred to in processing related to PWM control described later.

Next, the CPU 621 waits until the unit time elapses (step S17). Specifically, for example, the waiting process is 100 μs, and the process is resumed after 100 μs (the same applies hereinafter).
The CPU 621 also counts up the time limit by substituting “(limit counter) +1” in the “limit counter” (step S18).

  Thereafter, the CPU 621 takes in the detection value of the current detector 9 via the input / output port 625b, that is, the current value supplied to the EPS drive circuit 8 (step S19), and the taken-in current value (I) is smaller than “Ia”. It is determined whether or not “Ib” or less (step S20). When it determines with it not being below "Ib" (step S20: NO), CPU621 returns a process to step S17.

When it is determined that it is equal to or less than “Ib” (step S20: YES), the CPU 621 determines whether “(delay counter)” is “0” (step S21). If it is determined that it is not “0” (step S21: NO), the CPU 621 substitutes “(delay counter) −1” for “delay counter” (step S22), and returns the process to step S17.
Thus, by repeating steps S17 to S22, the time limit including the off-delay time is counted as an integral multiple of the unit time.

When it is determined in step S21 that “(delay counter)” is “0” (step S21: YES), the CPU 621 relates to “(limit counter)” counted up in step S18 and PWM control described later. The “(duty ratio)” set in the process is multiplied by the given “(limit rate)”, and the result is converted into an integer and substituted into the “reduction on time” (step S23).
Thereby, the time during which the control pulse of PWM control is reduced during the time limit is calculated, and the calculated value converted to an integer is substituted into the “reduction on time”.

Thereafter, the CPU 621 determines whether or not “(reduction on time)” is equal to or greater than “Tth” (step S24). When it is determined that it is equal to or greater than “Tth” (step S24: YES), the CPU 621 substitutes “Tth” for “reduction on time” (step S25).
Thereby, when the time when the control pulse is reduced exceeds “Tth”, the content of “reduction on time” is replaced with “Tth”. Therefore, as shown in FIG. 3C, when the degree of decrease in the temperature of the heater Ha saturates, the “reduction on time” should not exceed “Tth”.

  When the process of step S25 is completed and when it is determined in step S24 that “(reduction on time)” is not equal to or greater than “Tth” (step S24: NO), the CPU 621 sets an “energization counter” that counts the energization time. The initial value “0” is substituted (step S26), and “DC” is substituted for “energized state” (step S27). Then, the CPU 621 turns on the gate of the FET 61 via the input / output port 625a (step S28). From this time, a direct current is supplied to the heater Ha.

Next, the CPU 621 waits until the unit time elapses (step S29), and further substitutes “(energization counter) +1” in the “energization counter” (step S30) to count up the energization time. Then, the CPU 621 converts the multiplication value of “(energization counter)” and “1− (duty ratio)” into an integer and substitutes it into “integrated off time” (step S31).
In step S31, the multiplication value of “(energization counter)” and “(duty ratio)” may be subtracted from “(energization counter)”, and the subtraction value may be substituted into the “energization counter”.

Thereafter, the CPU 621 determines whether “(integrated off time)” is equal to or greater than “(reduction on time)” (step S32). When it determines with it not being above (step S32: NO), CPU621 returns a process to step S29.
In this way, steps S29 to S32 are repeated until “(integrated off time)” reaches “(reduction on time)”.

  When it is determined that “(integrated off time)” is equal to or greater than “(reduction on time)” (step S32: YES), the CPU 621 substitutes “PWM” for “energized state” (step S33). Then, the CPU 621 determines whether “(PWM state)” indicating the state of the control pulse is “off” (step S34). When determining that it is not “off” (“on”), the CPU 621 ends the process while keeping the gate of the FET 61 on. If it is determined to be “off” (step S34: YES), the CPU 621 turns off the gate of the FET 61 via the input / output port 625a (step S35), and ends the process. Thereby, the supply of the direct current to the heater Ha is terminated.

FIG. 5 is a flowchart showing a processing procedure of the CPU 621 related to the PWM control of the current supplied to the heater Ha. The following processing is executed as needed according to a control program stored in advance in the ROM 622, and is executed again every time the processing is completed. The outline of the processing here is that PWM control is performed except when “ON / OFF” is assigned to “PWM state” at the timing when the control pulse should be turned ON / OFF, and “(energized state)” is “DC”. The control pulse is turned on only for a time according to the “duty ratio” (“limit duty ratio” in the case of the limited time).
Note that “PWM cycle” is a known constant corresponding to the control cycle, and “limit duty ratio” is a variable stored in the RAM 623.

  The CPU 621 takes in the on / off state of the switch SW1 of the heater Ha via the input / output port 625c (step S41), and determines whether or not the switch SW1 is on (step S42). When it determines with not being turned on (step S42: NO), CPU621 returns a process to step S41. Therefore, the PWM control for the heater Ha is not executed while the SW1 is turned off.

When it is determined that the switch SW1 is turned on (step S42: YES), the CPU 621 calculates a duty ratio for PWM control of the current supplied to the heater Ha (step S43). The calculated duty ratio is stored in the variable “duty ratio”.
In this case, the CPU 621 may communicate with the charging control ECU 5 through communication means (not shown) to capture the voltage value of the in-vehicle battery 4 and determine the duty ratio based on the acquired voltage value. Since PWM control itself is publicly known, detailed description thereof is omitted here.

Thereafter, the CPU 621 substitutes the product of “(duty ratio)” and “1− (limit rate)” for “limit duty ratio” (step S44). Thereby, the duty ratio during the time limit is calculated and stored.
Next, the CPU 621 determines whether or not “(energized state)” set in FIG. 4 is “restricted” (step S45). When it is determined that it is not “restricted” (step S45: NO), the CPU 621 converts the multiplication value of “PWM period” and “(duty ratio)” into an integer and substitutes it for “on time” (step S46). Advances to step S48.

  When it is determined that “(energization state)” is “restricted” (step S45: YES), CP 621 converts the “PWM period” and “(restricted duty ratio)” into an integer and “on time” (Step S47). Thereafter, the CPU 621 determines whether or not “(ON time)” is “0” (step S48). When it determines with it being "0" (step S48: YES), CPU621 advances a process to step S52 mentioned later, without turning on the control pulse of PWM control. If it is determined that “(ON time)” is not “0” (step S48: NO), the CPU 621 substitutes “ON” for “PWM state” (step S50), and at the same time, the FET 61 via the input / output port 625a. Is turned on (step S51). This turns on the control pulse.

  Next, the CPU 621 substitutes “0” for a “PWM counter” that counts the ON time of the control pulse (step S52). Then, the CPU 621 waits until the unit time elapses (step S53), and further substitutes “(PWM counter) +1” for the “PWM counter” (step S54) to count up the ON time of the control pulse. Thereafter, the CPU 621 determines whether or not “(PWM counter)” has reached the “PWM period” (step S55). When it is determined that the “PWM period” has been reached (step S55: YES), the CPU 621 ends the process. Thereby, the process for 1 period of PWM control is complete | finished.

  When it is determined that the “PWM cycle” has not been reached (step S55: NO), the CPU 621 determines whether “(PWM counter)” has reached “(on time)” (step S56). If it is determined that “(on time)” has not been reached (step S56: NO), the CPU 621 returns the process to step S53. Thus, by repeating steps S53 to S56, the time during which the control pulse is turned on is counted as an integral multiple of the unit time.

  When it is determined that “(PWM counter)” has reached “(ON time)” (step S56: YES), the CPU 621 substitutes “OFF” for “PWM state” (step S57). Then, the CPU 621 determines whether or not “(energized state)” is “direct current” (step S58). When it determines with it being "DC" (step S58: YES), CPU621 returns a process to step S53, without turning off a control pulse. When it is determined that it is not “DC” (step S58: NO), the CPU 621 turns off the gate of the FET 61 via the input / output port 625a (step S59). This turns off the control pulse.

Thereafter, the CPU 621 determines whether or not “(energized state)” is “PWM” (step S60). When it determines with it not being "PWM" (step S60: NO), CPU621 returns a process to step S53, without taking in the electric current value of heater Ha. When it is determined that it is “PWM” (step S60: YES), the CPU 621 takes in the detection value of the current detector 10, that is, the current value supplied to the heater Ha via the input / output port 625d (step S61). The current value (I) is substituted for “heater current” (step S62), and the process returns to step S53.
The current value substituted for “heater current” in step S62 is not referred to in the first embodiment.

As described above, according to the first embodiment, when the PWM control of the power supplied to the heater is limited, the DC power is supplied from the in-vehicle power source to the heater under appropriate conditions after the limitation is released.
As a result, the amount of power that should have been supplied to the heater while the supply of power is restricted is quickly compensated by an appropriate amount while DC power is being supplied to the heater. Accordingly, when the supply of electric power to the PWM-controlled heater is restricted / released, the heater can be quickly returned to the temperature before the restriction.

Further, when the supply of power by PWM control is limited, the supplied power can be cut off 100%.
Therefore, the electric power to be supplied to the heater while it is restricted can be directed to the EPS driving circuit to the maximum extent.

Furthermore, since the restriction on the power supplied to the heater is released, “(integrated off time)” (total amount of off time in each control cycle of PWM control) is “(reduced on time)” (reduced by the restriction) The DC power is supplied from the on-vehicle power source to the heater until the total amount of on-time is equal to or greater.
Accordingly, the temperature of the heater that has decreased while the supply of power is restricted can be quickly canceled out while the DC power is being supplied.

Furthermore, when “(reduction on time)” is equal to or greater than “Tth”, DC power is supplied from the in-vehicle power source to the heater until “(integrated off time)” is equal to or greater than “Tth”.
Therefore, while supplying DC power, it is possible to prevent the power from being excessively supplied beyond the amount necessary for offsetting the lowered heater temperature.

Furthermore, “(duty ratio)” (corresponding to the time during which power supply to the heater is restricted) is added to “(duty ratio)” (duty ratio of PWM control before restriction is made) and “( The “reduction on-time” (total amount of on-time reduced) is calculated by multiplying by “limit rate)” (the rate at which the duty ratio has been reduced due to the restriction).
Accordingly, the “reduction on time” can be easily obtained with a small error.

Furthermore, the product of “(energization counter)” and “(duty ratio)” from “(energization counter)” (corresponding to the time counted from when the restriction on the power supply to the heater is released). Is subtracted to calculate the “integrated off time”.
Therefore, the “integrated off time” can be easily acquired with a small error.

Furthermore, the activation of the EPS drive circuit is detected when the current value supplied to the EPS drive circuit is equal to or greater than “Ia”.
Therefore, it is possible to start limiting the supply of power to the heater following the increase in the load current of the EPS drive circuit.

Furthermore, when the load current value of the EPS drive circuit is equal to or smaller than “Ib” which is smaller than “Ia”, a hysteresis is provided so as to release the restriction on the supply of power to the heater.
Therefore, it is possible to suppress the influence of noise included in the load current of the EPS drive circuit.

(Embodiment 2)
In the first embodiment, when the detected value of the current detector 9 is equal to or greater than “Ia”, the activation of the EPS drive circuit 8 is detected and the power is limited. In contrast to the configuration in which the DC power is supplied until the time) "or more, the second embodiment activates the headlamp 11 when it detects that the switch SW2 that supplies power to the headlamp 11 is turned on. In this configuration, the electric power is detected and limited, and the DC electric power is supplied until the heater current value becomes a predetermined threshold value or less.

FIG. 6 is a block diagram showing a schematic configuration of the vehicle power supply device according to Embodiment 2 of the present invention. The output voltage of the vehicle-mounted battery 4 is applied to the headlamp 11 through the fuse F1 and the switch SW2. One circuit of the switch SW1 is connected to the input terminal of the input / output port 625b.
Other configurations and connections are the same as the schematic configuration (FIG. 1) of the vehicle power supply device according to the first embodiment, and a description thereof will be omitted.

  FIG. 7 is a timing chart schematically showing how the temperature of the heater Ha changes when the power supplied to the heater Ha is limited when the activation of the headlamp 11 is detected. In the figure, the horizontal axis indicates time. FIG. 7A shows a change in the load current to the headlamp 11, and the vertical axis shows the current value. 7 (b) and 7 (c) are the same as FIGS. 2 (b) and 2 (c) of the first embodiment, respectively, and thus description thereof is omitted.

When the switch SW2 that supplies current to the headlamp 11 is turned on and activation is detected, the current supplied to the heater Ha is limited as shown in FIG. 7A. The time limit for limiting the current supplied to the heater Ha is continued until a time obtained by adding a known load on time and off delay time has elapsed.
The time delay may not include the off delay time.

FIG. 8 is a flowchart showing the processing procedure of the CPU 621 for restricting / releasing the supply of current to the heater Ha. The following processing is executed as needed according to a control program stored in the ROM 622 in advance.
Note that “heater current” and “start-up time” are variables stored in the RAM 623. The “heater current” is substituted with the current value acquired in step 61 of FIG. 5, and the content is just before the current supplied to the heater Ha is limited and the control pulse is on. This is the current value supplied to the heater Ha.

  The CPU 621 takes in the on / off state of the switch SW2 that supplies current to the headlamp 11 via the input / output port 625b (step S70), and determines whether the switch SW2 is turned on (step S71). When it determines with not being turned on (step S71: NO), CPU621 returns a process to step S70.

  When it is determined that the switch SW2 is turned on (step S71: YES), the CPU 621 detects the activation of the headlamp 11 and substitutes “restriction” for “energized state” (step S72). The gate of the FET 61 is turned off via 625a (step S73). At this time, the current supplied to the heater Ha is limited. Thereafter, the CPU 621 assigns an initial value “0” to the “limit counter” that counts the limit time (step S74), and the “load on time” and the “load on time” shown in FIG. The added value of “off delay” is substituted (step S75).

Next, the CPU 621 waits until the unit time elapses (step S76), and further substitutes “(limit counter) +1” for the “limit counter” (step S77) to count up the limit time. Then, the CPU 621 determines whether “(limit counter)” is equal to or greater than “(start-up time)” (step S78). If it is determined that it is not equal to or greater than “(start-up time)” (step S78: NO), the CPU 621 returns the process to step S76.
In this way, by repeating steps S76 to S78, the time limit is counted as an integral multiple of the unit time.

  When it is determined that “(limit counter)” is equal to or greater than “(start-up time)” (step S78: YES), the CPU 621 substitutes “DC” for “energized state” (step S79). Then, the CPU 621 turns on the gate of the FET 61 via the input / output port 625a (step S80). From this time, a direct current is supplied to the heater Ha. Thereafter, the CPU 621 takes in the detection value of the current detector 10 via the input / output port 625d, that is, the current value supplied to the heater Ha (step S59), and the taken-in current value (I) is stored in the RAM 623. It is determined whether or not “(heater current)” or less is reached (step S82). When it determines with it not being below (step S82: NO), CPU621 returns a process to step S81.

  If it is determined that the value is “(heater current)” or less (step S82: YES), the CPU 621 substitutes “PWM” for “energized state” (step S83), and then “(PWM state)” is “off”. Is determined (step S84). If it is determined that it is not “off” (“on”) (step S84: NO), the CPU 621 ends the process with the gate of the FET 61 turned on. If it is determined that it is “off” (step S84: YES), the CPU 621 turns off the gate of the FET 61 via the input / output port 625a (step S85) and ends the process. Thereby, the supply of the direct current to the heater Ha is terminated.

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the detailed description is abbreviate | omitted.

As described above, according to the second embodiment, DC power is supplied from the in-vehicle power source to the heater until the current value supplied to the heater becomes a predetermined threshold value or less.
Therefore, it is possible to quickly reduce the load current, which has been increased due to temperature drop while the supply of power to the heater is restricted, to a predetermined current value while supplying DC power. It becomes.

Further, the current value to be supplied to the heater is detected and stored in the RAM before restricting the power supply to the heater, and when the restriction is released, the current value to be supplied to the heater is stored in the RAM. DC power is supplied from the in-vehicle power source to the heater until the current value becomes lower than the current value.
Therefore, the current value before the power supply is restricted while the DC current is supplied to the load current that has been reduced in temperature while the supply of power to the heater is restricted. It is possible to reduce it quickly.

Furthermore, activation of the headlamp is detected when power supply to the headlamp is turned on.
Accordingly, it is possible to prevent the start performance of the headlamp from being impaired.

Furthermore, the restriction on the supply of electric power to the heater is released after a time obtained by adding the “load on time” and the “off delay” from the time when the supply of electric power to the headlamp is turned on.
Therefore, it is possible to continue to limit the power supply to the heater for the start time so that the start performance of the headlamp whose start time is known is not impaired.

(Embodiment 3)
In the second embodiment, DC power is supplied until the heater current value becomes equal to or less than a predetermined threshold value, whereas in the third embodiment, the PWM control OFF time is sequentially set from “(reduced ON time)”. In this mode, DC power is supplied until the result of subtraction becomes “0”.

FIG. 9 is a flowchart showing the processing procedure of the CPU 621 for restricting / releasing the supply of current to the heater Ha. The following processing is executed as needed according to a control program stored in the ROM 622 in advance.
Since steps S70 to S78 are the same as those in FIG. 8, the description thereof is omitted.

If it is determined in step S78 that “(limit counter)” is equal to or greater than “(startup time)” (step S78: YES), the CPU 621 counts up “(limit counter)” in step S77 and performs PWM control. Multiplying “(duty ratio)” set in the processing relating to “(duty ratio)” and the given “(limitation rate)”, the result is converted to an integer and substituted into “reduction on time” (step S87).
Thereby, the time during which the control pulse of PWM control is reduced during the time limit is calculated, and the calculated value converted to an integer is substituted into the “reduction on time”.

Thereafter, the CPU 621 determines whether “(reduction on time)” is equal to or greater than “Tth” (step S88). If it is determined that it is equal to or greater than “Tth” (step S88: YES), the CPU 621 substitutes “Tth” for “reduction on time” (step S89).
Thereby, when the time when the control pulse is reduced exceeds “Tth”, the content of “reduction on time” is replaced with “Tth”. Therefore, as shown in FIG. 3C, when the degree of decrease in the temperature of the heater Ha saturates, the “reduction on time” should not exceed “Tth”.

  When the process of step S89 is completed and when it is determined in step S88 that “(reduction on time)” is not equal to or greater than “Tth” (step S88: NO), the CPU 621 sets the “energization counter” to count the energization time. “(Reduction ON time)” is substituted (step S90), and “DC” is substituted for “energized state” (step S91). Then, the CPU 621 turns on the gate of the FET 61 via the input / output port 625a (step S92). From this time, a direct current is supplied to the heater Ha.

  Next, the CPU 621 waits until the unit time has elapsed (step S93). Further, the CPU 621 determines whether “(PWM state)” is “off” (step S94). When it is determined that it is “off” (step S94: YES), the CPU 621 substitutes “(energization counter) -1” for the “energization counter” (step S95) and counts down the conduction time. Thereby, when the control pulse is OFF, the content of the “energization counter” (the initial value is “(reduction on time)”) is counted down.

  When the process of step S95 is completed and when it is determined in step S94 that it is not “OFF” (step S94: NO), the CPU 621 determines whether “(energization counter)” is equal to or less than “0”. (Step S96). If it is determined that it is not less than “0” (step S96: NO), the CPU 621 returns the process to step S93. When it is determined that the value is “0” or less (step S96: YES), the CPU 621 substitutes “PWM” for “(energized state)” (step S97), and turns off the gate of the FET 61 via the input / output port 625a. (Step S98), and the process ends. Thereby, the supply of the direct current to the heater Ha is terminated.

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1 and 2, and the detailed description is abbreviate | omitted.

As described above, according to the third embodiment, the off time of each control cycle of the PWM control is calculated from “(reduced on time)” (total amount of on time reduced due to restriction of power supplied to the heater). DC power is supplied from the in-vehicle power source to the heater until the result of sequential subtraction becomes 0 or less.
Accordingly, the temperature of the heater that has decreased while the supply of power is restricted can be quickly canceled out while the DC power is being supplied.

In addition, when “(reduction on time)” is equal to or greater than “Tth”, the result obtained by sequentially subtracting the off time of each control cycle of PWM control from “(energization counter)” having an initial value of “Tth” is 0 or less. DC power is supplied from the in-vehicle power source to the heater until
Therefore, it is possible to prevent excessive power from being supplied past the amount necessary for offsetting the lowered heater temperature while DC power is being supplied.

It is a block diagram which shows schematic structure of the vehicle power supply device which concerns on Embodiment 1 of this invention. 6 is a timing chart schematically showing how the heater temperature changes when the power supplied to the heater is limited when the activation of the EPS drive circuit is detected. 6 is a timing chart schematically showing how the heater temperature changes when the power supplied to the heater is limited when the activation of the EPS drive circuit is detected. It is a flowchart which shows the process sequence of CPU which restrict | limits / releases supply of the electric current to a heater. It is a flowchart which shows the process sequence of CPU which concerns on PWM control of the electric current supplied to a heater. It is a block diagram which shows schematic structure of the vehicle power supply device which concerns on Embodiment 2 of this invention. It is a timing chart which shows typically a mode that the temperature of a heater changes when electric power supplied to a heater is restricted when starting of a headlamp is detected. It is a flowchart which shows the process sequence of CPU which restrict | limits / releases supply of the electric current to a heater. It is a flowchart which shows the process sequence of CPU which restrict | limits / releases supply of the electric current to a heater.

Explanation of symbols

4 Car battery (car power supply)
5 Charge control ECU
6 Relay box 61 FET (PWM control means)
62 Control part (control means)
621 CPU
622 ROM (means for storing)
623 RAM
624 timer (first timing means, second timing means)
625a, 625b, 625c, 625d I / O port 8 EPS drive circuit (second load)
9 Current detector (second load current detection means)
10 Current detector (first load current detection means)
11 Headlamp (second load)
Ha heater (first load)
SW2 switch (power supply detection means)

Claims (14)

Means for PWM-controlling the power supplied from the in-vehicle power source to the first load, start-up detecting means for detecting the start of the second load to be supplied with power from the in-vehicle power source, A vehicle power supply apparatus comprising: a control unit that restricts the supply of electric power by the PWM control and releases the restriction after the restriction;
The vehicular power supply apparatus is characterized in that the control means continuously supplies the electric power from the release of the restriction to an appropriate time point.   2. The vehicle power supply device according to claim 1, wherein the control unit is configured not to supply the electric power when the restriction is imposed. 3. First calculation means for calculating a total amount of on-time reduced by the restriction with respect to on-time of each control cycle of the PWM control;
Second calculating means for calculating a total amount of off time of each control period after the control means releases the restriction;
The control means continuously supplies the power until the total amount of off time calculated by the second calculation means is equal to or greater than the total amount of reduced on time calculated by the first calculation means. The power supply device for vehicles according to claim 1 or 2 characterized by things. Means for determining whether the total amount of reduced on-time calculated by the first calculation means is equal to or greater than a predetermined time;
When the means determines that the above is true, the control means is configured to continuously supply the power until the total amount of off time calculated by the second calculation means reaches the predetermined time or more. The vehicle power supply device according to claim 3. First control means for measuring the time when the control means causes the restriction;
The first calculation means calculates the duty ratio of the PWM control before the restriction is imposed and the rate at which the duty ratio is reduced due to the restriction, during the time counted by the first timing means. The vehicular power supply apparatus according to claim 3 or 4, wherein the total amount of on-time reduced by multiplication is calculated. A second timing means for starting timing when the control means releases the restriction;
The second calculating means calculates a total amount of off-time by subtracting the product of the time and the duty ratio of the PWM control from the time counted by the second time measuring means. Item 6. The vehicle power supply device according to any one of Items 3 to 5. A calculation means for calculating a total amount of on-time reduced by the restriction for the on-time of each control cycle of the PWM control;
Subtracting means for sequentially subtracting off time of each control cycle from the total amount calculated by the calculating means,
3. The vehicle power supply device according to claim 1, wherein the control unit continuously supplies power until a subtraction result calculated by the subtraction unit becomes 0 or less. Means for determining whether the total amount of reduced on-time calculated by the calculation means is equal to or greater than a predetermined time;
8. The vehicle power supply device according to claim 7, wherein, when the means determines that the above is true, the subtracting means sequentially subtracts the off time of each control cycle from the predetermined time. Comprising a first load current detecting means for detecting a current value supplied to the first load;
3. The vehicle according to claim 1, wherein the control unit continuously supplies power until the current value detected by the first load current detection unit becomes equal to or less than a predetermined threshold value. Power supply. Means for storing a current value detected by the first load current detection means before the control means causes the restriction;
The vehicle power supply device according to claim 9, wherein the current value stored by the means is used as the predetermined threshold value. A second load current detecting means for detecting a current value supplied from the in-vehicle power source to the second load;
The start detection means detects the start when the current value detected by the second load current detection means is greater than or equal to a first threshold value. The vehicle power supply device described in 1.   12. The control unit according to claim 11, wherein when the current value detected by the second load current detection unit is equal to or less than a second threshold value that is smaller than the first threshold value, the control unit releases the restriction. The power supply device for vehicles as described. Power supply detection means for detecting the start of supply of power to the second load;
The vehicle power supply device according to any one of claims 1 to 12, wherein when the power supply detection means detects a start, the start detection means detects a start. When the power supply detection means detects the start, comprising means for starting time measurement,
14. The vehicle power supply device according to claim 13, wherein the control means releases the restriction when the means measures a predetermined time.

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