JP5446142B2 - Driving method and driving apparatus - Google Patents

Description

  The present invention relates to a driving method and a driving apparatus that suppress an inrush current flowing through a load when driving of the load is started.

  Lamps such as automobile headlamps and fog lamps emit light when energized filaments generate heat to some extent. For this reason, the illuminance of the lamp is related to the temperature of the filament. FIG. 6 is a diagram showing the relationship between the amount of current to the lamp and the lamp illuminance, which varies with the power supply time to the lamp or the filament temperature. Since the filament is cold at the start of lighting, as shown in FIG. 6, the lamp has substantially zero illuminance for a predetermined time, that is, does not emit light, and the illuminance increases as the temperature of the filament increases. Thereafter, the lamp is steadily lit. In general, the filament has a resistance value at a low temperature (hereinafter referred to as a cold resistance value) of about one-tenth to one-tenth of the resistance value during steady lighting. For this reason, at the start of lighting, the resistance value of the filament is small, the rise of the current flowing through the filament is fast, and a large current (hereinafter referred to as inrush current) flows. Thereafter, as the filament temperature rises, the resistance value of the filament increases, and the current flowing to the lamp shifts to a steady state.

  When an inrush current flows through the lamp, problems such as filament deterioration due to rapid heat generation, welding of a power switch contact, and fusing of a fuse occur. In addition, when the current flowing at the start of lighting is limited and the inrush current is suppressed, the temperature of the filament of the lamp cannot be raised, and it takes time until the lamp is steadily lit. Therefore, Patent Document 1 proposes a control device that quickly increases the temperature and resistance value of the filament while suppressing inrush current.

The control device described in Patent Literature 1 performs initial lighting control for quickly increasing the temperature and resistance of the filament of the lamp prior to steady lighting control for lighting the lamp at the rated power load at the start of lamp lighting. ing. In the initial lighting control, the power supply time to the lamp is set to be shorter than the power supply time of the steady lighting control, and the power supply frequency is set to be larger than the power supply frequency of the steady lighting control. Thereby, the control apparatus described in Patent Document 1 can quickly increase the temperature and resistance value of the lamp filament while suppressing the inrush current. When the initial lighting control is switched to the steady lighting control, it is possible to ensure a predetermined brightness in a state where no inrush current is generated.
JP 2004-355887 A

  However, in the control device described in Patent Document 1, the inrush current does not continue to flow by shortening the power supply time to the lamp in the initial lighting control, and the peak value of the inrush current is suppressed. I can't. That is, in Patent Document 1, even if the inrush current can be suppressed from flowing for a long time, the peak value of the inrush current cannot be suppressed, and as a result, the inrush current flows. For this reason, Patent Document 1 cannot reliably solve the problems such as the deterioration of the filament due to the rapid heat generation as described above.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a driving method and a driving device capable of driving a load such as a lamp so that an inrush current does not flow beyond a suppression target value. It is to provide.

The drive method according to the present invention is a drive method for driving the load after controlling on / off of a switch that connects and disconnects the load and the battery, and repeatedly supplying and interrupting power to the load at a constant cycle. The time from the start of the inrush current flowing through the load to the current of the suppression target value is acquired and stored in advance for each cycle , and the stored time is stored in the storage order in order to supply power to the load in each cycle. as the on-time supply, characterized by on-off control of the pre-Symbol switch.

The driving method according to the present invention is characterized and Turkey to on-off control of the switch for a predetermined period.

The drive device according to the present invention is an on-off control of a switch that connects and disconnects a load and a battery, repeats supply and cut-off of power to the load at a constant period, and then drives the load. Storage means for acquiring and storing in advance for each period the time from when the inrush current flowing through the load starts to flow to the current of the suppression target value, and the time stored in the storage means in each order in each period as the on-time for supplying power to the load, and a controlling means for turning on and off the front Stories switch.

In the present invention, the time from when the inrush current flowing through the load starts to flow to the current of the suppression target value is defined as the on time for supplying power to the load, and the cycle for repeating the supply and interruption of power to the load is determined from the on time. Set longer. And based on the ON time which supplies electric power to load, and the set period, switch ON / OFF control is performed. Thereby, the inrush current more than the suppression target value does not flow to the load. By setting the suppression target value, the ON time, and the cycle according to the type of load, it is possible to prevent an inrush current from flowing at the start of load driving.
Further, according to the present invention, the duty ratio is gradually increased as the time from the start of the inrush current flowing to the load until the current of the suppression target value becomes longer as the resistance value of the load increases. The temperature and resistance value of the load can be controlled to be accelerated.

In the present invention, by performing on-off control of the switch in order to suppress rush current, drive start of the load only the period of performing O-off control is delayed. Therefore, by appropriately setting how long to perform on-off control, it is possible to prevent the start of driving the load is too delayed.

In the present invention, the time from when the inrush current flowing to the load starts to flow until the current of the suppression target value is reached is the on time for supplying power to the load, and the cycle for repeating the supply and interruption of power to the load is the on time. a longer set. Then, based on the on-time and set boss was periodically supplying power to a load, performs on-off control of the switch. Thereby, the inrush current more than the suppression target value does not flow to the load. Suppression target value, on-time and set Teisu isosamples according to the type of periodic load, it is possible to make the inrush current does not flow at start of driving the load.

  Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.

(Embodiment 1)
Embodiment 1 which concerns on this invention is demonstrated. FIG. 1 is a block diagram schematically illustrating a configuration of a lamp driving system using the control device according to the first embodiment.

  In addition to the control device 1, the lamp driving system includes a battery 2, a switching element 3, a lamp 4, a power switch 5, and the like. The battery 2 is a vehicle battery of 12V or 42V, for example. The lamp 4 is a bulb lamp that emits light when an energized filament generates heat to some extent, and is a headlamp such as a headlamp or a fog lamp. The lamp 4 is turned on or off when the power switch 5 is turned on or off by the driver. The switching element 3 is disposed between the battery 2 and the lamp 4 and electrically connects or disconnects the battery 2 and the lamp 4. The switching element 3 is subjected to PWM (Pulse Wide Modulation) control by the control device 1.

  The control device 1 includes a control unit 10, a storage unit 11, an input unit 12, an output unit 13, and the like. The control unit 10 is a microcomputer including a CPU (Central Processing Unit) or MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like connected by an internal bus. The controller 10 is driven by power supplied from the battery 2 through a power line (not shown), and performs various controls by the operation of the CPU or MPU according to a control program stored in the ROM. In the first embodiment, when the power switch 5 is turned on, the control unit 10 performs PWM control of the switching element 3 and performs initial lighting control for repeatedly turning on and off the switching element 3 for a predetermined period. Thereafter, the control unit 10 keeps the switching element 3 on, and performs steady lighting control for energizing the lamp 4 with DC (Direct Current).

  The input unit 12 is connected to the power switch 5 and outputs an ON / OFF detection signal of the power switch 5 to the control unit 10. The output unit 13 is connected to the switching element 3, and outputs a pulse signal for switching the switching element 3 on or off to the switching element 3.

  The storage unit 11 stores control parameters used when the control unit 10 performs PWM control of the switching element 3. The control parameters are a period L during which the initial lighting control is performed, a PWM control cycle T and a duty ratio D in the initial lighting control, and the like.

  The period T is a period during which the switching element 3 is turned on and off in the PWM control. The duty ratio D is a ratio of time (hereinafter referred to as time t) for turning on the switching element 3 to the period T. In other words, the time t is a power supply time for supplying the current from the battery 2 to the lamp 4. In the first embodiment, the time t is the time until the target value is reached at the rise of the current at the start of lighting of the lamp 4 shown in FIG. 6, that is, until the inrush current flowing at the start of lighting of the lamp 4 reaches the target value. Is the time. The target value is a current value that can cause problems such as degradation of the filament due to rapid heat generation. The time t, the period T, and the duty ratio D have a relationship of time t = period T × duty ratio D. The time t is obtained from FIG. 6, and optimal values are selected for the period T and the duty ratio D so as to satisfy the above-described relationship.

  The period L is a time for performing the initial lighting control. As will be described later, in the first embodiment, when the switching element 3 is turned on / off in the initial lighting control, the illuminance of the lamp 4 rises in comparison with the case where the switching element 3 is not turned on / off (see FIG. 6). Is delayed. Accordingly, there is a time difference from when the driver turns on the power switch 5 until the lamp 4 emits light. Therefore, the period L is set within a range in which a delay until the power switch 5 is turned on and the lamp 4 is lit is allowed.

  The time t, the period T, the duty ratio D, and the period L vary depending on the type of the lamp 4. For example, when the inrush current of 79.1 A [12.5 V] flowing to the lamp 4 is limited to 45 [A] or less and the light emission time (period L) of the lamp 4 is 250 [ms], time t = period T X Each parameter is determined so as to satisfy the duty ratio D <60 [μsec].

  In the control device 1 configured as described above, the initial lighting control and the steady lighting control performed by the control unit 10 when the power switch 5 is turned on will be described. FIG. 2 is a diagram schematically showing changes in the current flowing to the lamp 4 and the illuminance of the lamp 4 with respect to the pulse signal output to the switching element 3. The dotted line and the alternate long and short dash line in FIG. 2 are the same as those described with reference to FIG. 6, and are illustrated for comparison with the case of being controlled by the control device 1 according to the first embodiment.

  The initial lighting control is started when the control unit 10 detects that the power switch 5 detected through the input unit 12 is turned on. In the initial lighting control, the control unit 10 performs PWM control of the switching element 3 with the period T and the duty ratio D during the period L related to the control parameter. Specifically, the control unit 10 outputs a pulse signal having a cycle T and a duty ratio D to the switching element 3 as shown in FIG. In this case, after the switching element 3 is turned on for the time t, the switching element 3 repeats the operation that is turned off for the time “T−t” during the period L. Time t is the time until the inrush current that flows at the start of lighting of the lamp 4 reaches the target value. For this reason, even if the time t switching element 3 is turned on at the start of lighting of the lamp 4 having the smallest filament resistance value of the lamp 4, the current does not flow to the lamp 4 exceeding the target value. Thereby, the rush current which flows into the lamp | ramp 4 can be suppressed from a peak value to a target value.

  Moreover, the filament of the lamp 4 is warmed by the current by flowing the current to the lamp 4. As a general characteristic of the filament, even if the temperature does not drop suddenly in a short time and the current to the lamp 4 is cut off for a short time (time “Tt” in the first embodiment), the lamp While the current flows to 4 (time t in the first embodiment), the temperature of the heated filament does not decrease. For this reason, in the initial lighting control, when a current repeatedly flows to the lamp 4, the temperature of the filament of the lamp 4 gradually increases, and the resistance value of the filament also gradually increases. As the resistance value increases, the flowing current is gradually suppressed. As a result, as shown in FIG. 2, the rise of the current that flows when the switching element 3 is turned on gradually becomes gentle. For this reason, as shown in FIG. 2, the amount of current flowing to the lamp 4 gradually decreases from the target value over time.

  As described above, in the initial lighting control, the control unit 10 controls the switching element 3 so as to increase the temperature and resistance value of the filament of the lamp 4 while suppressing the inrush current flowing at the start of lighting of the lamp 4.

  The steady lighting control is started after the control unit 10 performs the initial lighting control during the period L. In the steady lighting control, the control unit 10 turns on the switching element 3 until the power switch 5 is switched off, and performs DC energization to the lamp 4. Since the temperature and resistance value of the filament of the lamp 4 are increased in the initial lighting control, a sudden inrush current does not flow even when the DC power is supplied to the lamp 4 by switching to the steady lighting control. Then, after the DC current is supplied to the lamp 4 and the temperature and resistance value of the filament of the lamp 4 become sufficiently large, the current flowing to the lamp 4 settles to a constant value. Further, after the temperature and resistance value of the filament of the lamp 4 are increased and sufficiently increased, the illuminance of the lamp 4 rises and becomes constant illuminance. As described above, the rise of the illuminance of the lamp 4 is delayed in comparison with the case where the switching element 3 is not turned on / off (the chain line in the figure).

  Next, the operation of the control device 1 will be described. FIG. 3 is a flowchart illustrating processing executed by the control device 1. The process illustrated in FIG. 3 is started by the control unit 10 of the control device 1 when the ignition switch is turned on, for example.

  The control unit 10 performs initial processing such as resetting of the stored contents of the RAM (S1). Next, the control unit 10 determines whether or not the power switch 5 is turned on (S2). If the power switch 5 is not switched on (S2: NO), the control unit 10 moves the process to S9. When the power switch 5 is switched on (S2: YES), the control unit 10 acquires control parameters from the storage unit 11 (S3).

  Next, the control part 10 performs PWM control of the switching element 3 based on the acquired control parameter (S4). That is, the control unit 10 performs initial lighting control, outputs a pulse signal to the switching element 3 as described with reference to FIG. Thereby, the temperature and resistance value of the filament of the lamp 4 can be increased.

  Next, the control unit 10 determines whether or not a period L has elapsed since the start of the initial lighting control (S5). If the period L has not elapsed (S5: NO), the control unit 10 continues the PWM control. When the period L has elapsed (S5: YES), the control unit 10 switches from the initial lighting control to the steady lighting control, and switches the switching element 3 to always on (S6). Thereby, DC energization is performed to the lamp 4. Thereafter, the control unit 10 determines whether or not the power switch 5 is switched off (S7). If the power switch 5 is not switched off (S7: NO), the control unit 10 waits until the power switch 5 is switched off. The lamp 4 gradually increases in illuminance after the control unit 10 starts PWM control of the switching element 3 and then becomes constant illuminance.

  When the power switch 5 is switched off (S7: YES), the control unit 10 switches the switching element 3 off (S8). As a result, the lamp 4 is turned off. Thereafter, the control unit 10 determines whether or not to end the operation of the control device 1 (S9). For example, the operation of the control device 1 ends when the ignition switch is turned off. When the operation of the control device 1 is not terminated (S9: NO), the control unit 10 moves the process to S2. When the operation of the control device 1 is to be ended (S9: YES), the control unit 10 ends this process.

  In the process of FIG. 3, immediately after the power switch 5 is turned off, the temperature and resistance value of the filament of the lamp 4 are increased. Therefore, when the power is turned on again within a predetermined time, the control unit 10 performs initial lighting. Control may not be performed.

  As described above, in the first embodiment, control parameters such as a period in PWM control and a constant duty ratio are set in advance from the time until the inrush current flowing at the start of lighting of the lamp 4 reaches a target value. Then, the temperature and resistance value of the filament of the lamp 4 can be increased while suppressing the flowing inrush current by performing on / off control of the switching element 3 based on a preset control parameter at the start of lighting of the lamp 4.

(Embodiment 2)
Next, Embodiment 2 according to the present invention will be described. In the first embodiment, PWM control is performed using a constant duty ratio. However, the second embodiment is different from the first embodiment in that the duty ratio is changed. Hereinafter, only different points will be described, and the same members as those of the first embodiment will be referred to by the same reference numerals and the description thereof will be omitted.

  In the second embodiment, the storage unit 11 stores control parameters including a period L for performing the initial lighting control, a PWM control period T in the initial lighting control, and a time t (n) for turning on the switch element 3 in one cycle. ing. n is the number of times the switching element 3 is turned on, that is, the number of times of repeating power feeding. The time t (n) is set to increase with time (as n increases), and t (1) <t (2) <t (3) <t (4). Since the period T is unchanged, the duty ratio D (n) gradually increases with time from the relationship of time t = period T × duty ratio D, and D (1) <D (2),. , <D (n).

  FIG. 4 is a diagram schematically showing the amount of current flowing to the lamp 4 over time. FIG. 5 is a diagram schematically showing a change in the current flowing to the lamp 4 as a result of the PWM control. FIG. 4 shows a current I (n) that flows when the switching element 3 is turned on for the nth time. In FIG. 5, the change in the illuminance of the lamp 4 is omitted because it is substantially the same as that in FIG.

  As described in the first embodiment, when the power supply to the lamp 4 is repeatedly performed in the initial lighting control, the resistance value of the filament of the lamp 4 gradually increases. For this reason, as shown in FIG. 4, the rising of the current I (n) flowing to the lamp 4 gradually becomes gentle as the number of times of repeating power feeding (the number n of times the switching element 3 is turned on) increases. Since the rise becomes gentle, the amount of current flowing within the same time gradually decreases every time power feeding is repeated, and the time until the current reaches the target value also becomes longer.

  The control parameter time t (n) stored in the storage unit 11 gradually increases with time. For this reason, as shown in FIG. 5, in the initial lighting control according to the second embodiment, the time t (n) for turning on the switching element 3 becomes longer every time power feeding is repeated. Further, every time the power feeding is repeated, the rising of the current gradually becomes gentle, and the amount of current flowing at the time of power feeding gradually decreases. Thus, the temperature and resistance value of the filament of the lamp 4 can be increased in the initial lighting control. For this reason, even if DC switching is applied to the switching lamp 4 in the steady lighting control, no sudden inrush current flows.

  As described above, in the second embodiment, the control parameter is set so that the time t (n) and the duty ratio D (n) are increased every time power feeding is repeated. As the control unit 10 performs the initial lighting control based on this control parameter, the inrush current flowing to the lamp 4 can be suppressed from the peak value to the target value, as in the first embodiment. In addition, since the operation | movement of the control apparatus 1 which concerns on Embodiment 2 is the same as Embodiment 1, description is abbreviate | omitted.

  In the first and second embodiments, the control parameter determined in advance is stored and the drive control of the lamp 4 is performed. However, the control parameter may be determined when the drive control of the lamp 4 is started. Specifically, the time until the target value is reached is stored in the storage unit 11 of the control device 1. The control unit 10 determines the period T, time t (n), and duty ratio D from the time stored in the storage unit 11 at the start of driving of the lamp 4. Based on the determined period T, time t (n), and duty ratio D, PWM control of the switch element 3 is performed.

  The preferred embodiments of the present invention have been specifically described above, but each configuration, processing operation, and the like can be changed as appropriate, and are not limited to the above-described embodiments.

It is a block diagram which shows typically the structure of the lamp drive system using the control apparatus which concerns on Embodiment 1. FIG. It is a figure which shows typically the change of the electric current which flows into a lamp, and the illumination intensity of a lamp as a result of PWM control. It is a flowchart which shows the process which a control apparatus performs. It is a figure which shows typically the change of the electric current which flows into a lamp | ramp with progress of time. It is a figure which shows typically the change of the electric current which flows into a lamp as a result of performing PWM control. It is the figure which showed the relationship between the electric current amount to a lamp which changes with the electric power feeding time to a lamp | ramp, or a filament temperature, and lamp | ramp illumination intensity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Battery 3 Switching element 4 Lamp 5 Power switch 10 Control part 11 Memory | storage part

Claims (3)

In a driving method of driving the load after controlling on / off of a switch that connects and disconnects the load and the battery, and repeatedly supplying and cutting off the power to the load at a constant cycle,
The time from the start of the inrush current flowing through the load to the current of the suppression target value is acquired and stored in advance for each cycle ,
Driving method the stored time in the storage order, as the on-time for supplying power to the load at each cycle, characterized by on-off control of the pre-Symbol switch.   The driving method according to claim 1, wherein the switch is on / off controlled only for a predetermined period. In a drive device for driving the load after controlling on / off of a switch that connects and disconnects the load and the battery, and repeatedly supplying and cutting off the power to the load at a constant cycle,
Storage means for acquiring and storing in advance for each period the time from the start of the inrush current flowing through the load until the current of the suppression target value is reached;
The order storage time which the storage means stores, as the on-time for supplying power to the load at each cycle, the drive device characterized by a control means for turning on and off the front Stories switch.

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