JP5968075B2 - Charging apparatus, control method thereof, and control program - Google Patents

Description

  The present invention relates to a charging device for charging a light emitting device such as a strobe device, a control method thereof, and a control program, and more particularly to a charging device capable of shortening the charging time of a main capacitor of the light emitting device.

  In general, a strobe device (hereinafter simply referred to as a strobe), which is one of light emitting devices, has a main capacitor for storing light emission energy. The main capacitor is charged by the charging device, and the light emission energy is accumulated in the main capacitor.

  Conventionally, in order to shorten the charging time of the main capacitor, there is a charging device in which the upper limit value of the charging current is set according to the input power supply voltage of the charging circuit and the charging voltage of the main capacitor. In this charging apparatus, the upper limit value of the charging current is controlled so that the power supply voltage drop during charging and the charging voltage of the main capacitor become an optimal combination. This shortens the charging time of the main capacitor, that is, the strobe (see Patent Document 1).

JP 2000-194041 A

  By the way, in the charging device described in Patent Document 1, when setting the upper limit value of the charging current, it is necessary to limit the current so that excessive current does not flow to the input side of the charging circuit. Furthermore, it is necessary to consider the oscillation of the booster circuit for charging the main capacitor. On the other hand, when controlling the charging current of the main capacitor in order to shorten the charging time, it is necessary to optimize the on / off control of the primary side switching element connected in series with the primary winding of the booster circuit.

  However, when the upper limit value of the charging current is set as in Patent Document 1, it is necessary to limit the current so that excessive current does not flow through the primary winding of the booster circuit. Is difficult to shorten sufficiently. On the other hand, if the current flowing through the primary winding is not limited, an excessive current flows through the primary side switch element and the primary side switch element is damaged, which is not preferable for safety.

  Accordingly, an object of the present invention is to provide a charging device, a control method, and a control program that can reduce the charging time of a main capacitor while ensuring safety.

In order to achieve the above object, a charging device according to the present invention includes a step-up transformer having a primary winding and a secondary winding, and is connected in series to the primary winding from a power source to the primary winding. A switching element that controls energization of the power source and energy storage means that is connected to the secondary winding and stores energy from the boosting transformer, and is stored in the boosting transformer when the switching element is turned on. A charging device that discharges energy from the secondary winding to the energy storage means when the switch element is turned off, wherein the charging voltage detection means detects the charging voltage of the energy storage means as a detection charging voltage; and A discharge time measuring means for measuring a time during which energy is discharged from the secondary winding to the energy storage means as a secondary side discharge time; Current peak value calculating means for calculating the peak value of the current flowing through the primary winding as a primary current peak value according to the secondary discharge time and the peak value of the current flowing through the primary winding Switch element on-time calculating means for calculating the on-time of the switch element as a calculated on-time according to the current peak value setting value and the primary-side current peak value, and the current flowing through the primary winding Switch element control means for performing on / off control of the switch element according to the calculated on-time without measuring .

A control method according to the present invention includes a step-up transformer having a primary winding and a secondary winding, a switching element connected in series to the primary winding and controlling energization from a power source to the primary winding. Energy storage means connected to the secondary winding for storing energy from the boosting transformer, and the switch element turns off the energy stored in the boosting transformer when the switch element is turned on. And a charging voltage detecting step for detecting a charging voltage of the energy storage means as a detected charging voltage, and a method for controlling the charging device for releasing the energy from the secondary winding to the energy storage means. A discharge time measuring step of measuring a time during which energy is discharged to the energy storage means as a secondary discharge time; the detected charging voltage; A current peak value calculation step for calculating the peak value of the current flowing through the primary winding as a primary current peak value according to the secondary discharge time, and the peak value of the current flowing through the primary winding are set. A switch element on-time calculating step for calculating an on-time of the switch element as a calculated on-time according to a current peak value setting value and the primary-side current peak value, and measuring a current flowing through the primary winding. And a switching element control step of controlling on / off of the switching element according to the calculated on-time.

A control program according to the present invention includes a step-up transformer having a primary winding and a secondary winding, a switching element connected in series to the primary winding and controlling energization from a power source to the primary winding, Energy storage means connected to the secondary winding for storing energy from the boosting transformer, and the switch element turns off the energy stored in the boosting transformer when the switch element is turned on. A charging program that is used in a charging device that discharges from the secondary winding to the energy storage means when the charging is performed, and detects a charging voltage of the energy storage means as a detected charging voltage in a computer included in the charging device A detection step, and a time during which energy is released from the secondary winding to the energy storage means is a secondary-side release time. A discharge time measuring step for measuring, and a current peak value calculating step for calculating a peak value of a current flowing through the primary winding according to the detected charging voltage and the secondary discharge time as a primary current peak value. And a switch element on time for calculating an on time of the switch element as a calculated on time according to a current peak value setting value for setting a peak value of a current flowing through the primary winding and the primary current peak value A calculation step and a switch element control step of performing on / off control of the switch element in accordance with the calculated on time without measuring a current flowing through the primary winding are performed.

  According to the present invention, it is possible to shorten the charging time of energy storage means such as a main capacitor while ensuring safety.

It is a block diagram which shows the example about the structure of the strobe charging device by embodiment of this invention. FIG. 2 is a diagram for explaining an example of the configuration of the booster circuit shown in FIG. 1. It is a flowchart for demonstrating the charging operation of the strobe charging device shown in FIG.

  Hereinafter, an example of a charging device according to an embodiment of the present invention will be described with reference to the drawings. Here, a charging device (hereinafter referred to as a strobe charging device) for charging a strobe device that is one of light emitting devices used with an imaging device such as a camera will be described. However, the main capacitor is not limited to the strobe device. Can be applied to charge a light emitting device that emits light by discharging from the main capacitor.

  FIG. 1 is a block diagram showing an example of the configuration of the strobe charging device according to the embodiment of the present invention.

  The illustrated strobe charging device is used to charge a strobe device used with a camera. The strobe charging device is provided in a strobe device, for example.

  In FIG. 1, a power source 101 is, for example, a battery, and supplies a DC voltage to the strobe charging device. This DC voltage is applied to the booster circuit 102. The booster circuit 102 boosts the DC voltage and applies the output voltage to the main capacitor (energy storage means) 103 to charge the main capacitor 103. The illustrated booster circuit 102 is a so-called flyback booster switching power supply circuit.

  FIG. 2 is a diagram for explaining an example of the configuration of the booster circuit 102 shown in FIG.

  In FIG. 2, the booster circuit 102 includes a booster transformer (also referred to as a voltage conversion transformer) 302, and a primary side switch element 303 is connected to a primary winding 302 a of the booster transformer 302. When the primary side switch element 303 is turned on by the primary side switch element control unit 110, an input voltage is applied from the power source 101 to the primary winding 302a, and a current flows through the primary winding 302a. As a result, energy is stored in the step-up transformer 302.

  Thereafter, when the primary side switch element 303 is turned off by the primary side switch element control unit 110, the energy accumulated in the step-up transformer 302 is connected in series from the secondary winding 302b to the secondary winding 302b. Further, it is discharged to the main capacitor 103 through the secondary side rectifying element 304. The charging voltage of the main capacitor 103 is detected by the charging voltage detector 105.

  The primary switch element 110 repeats on / off control of the primary side switch element 303 until the charge voltage of the main capacitor 103 reaches a predetermined charge completion voltage, as will be described later.

  As described above, in the booster circuit 102, the energy accumulated in the boosting transformer 302 (that is, the primary winding 302a) is transferred from the secondary winding 302b to the secondary side connected to the secondary winding 302b. It is discharged to the main capacitor 103 via the rectifying element 304. At this time, the secondary side discharge time measuring unit (release time measuring means) 104 measures the time required for the release energy (secondary side release energy) from the secondary winding 302b to become zero from the start of the release. . Then, the secondary side discharge time measurement unit 104 outputs the measurement result (secondary side discharge time) to the primary side conduction current peak value calculation unit 106.

  A charging voltage detection unit (charging voltage detection means) 105 performs A / D conversion on the charging voltage of the main capacitor 103, and calculates a charging voltage detection value (digital value) corresponding to the charging voltage value as a primary side conduction current peak value calculation unit. It outputs to 106. The primary side conduction current peak value calculation unit 106 is given a primary side switching element on / off setting time from a primary side switching element on / off time setting unit 109 described later. The primary side conduction current peak value calculation unit (current peak value calculation means) 106 is a current that flows through the primary winding in the ON period defined by the primary side switch element ON / OFF set time, as will be described later. The peak value (primary winding current peak value) is calculated and output to the primary side switch element on-time calculating unit 107.

  The primary side switch element on-time calculating unit (switch element on-time calculating unit) 107 includes a primary winding current peak value and a primary side energizing current set value set by the primary side energizing current peak value setting unit 108. Are compared to calculate the primary-side switch element on-time. Then, the primary side switch element on time calculation unit 107 outputs the primary side switch element on time to the primary side switch element on / off time setting unit 109.

  The primary side switch element on / off time setting unit 109 is configured to turn on / off the primary side switch element based on the secondary side release time and the primary side switch element on time measured by the secondary side discharge time measurement unit 104. The off time is determined and output to the primary side switch element control unit 110. The primary side switch element control unit 110 performs on / off control of the primary side switch element 303 based on the primary side switch element on / off time.

  At this time, the primary side switch element control unit 110 performs on / off control of the primary side switch element 303 so that the peak value of the conduction current of the primary side switch element 303 is constant regardless of the power supply voltage.

  FIG. 3 is a flowchart for explaining the charging operation of the strobe charging device shown in FIG.

  When charging control is started in the strobe charging device, first, the primary side switch element on / off time setting unit 109 performs an initial setting process (step S200). Here, the primary side switch element on / off time setting unit 109 sets an initial value set in advance for the primary side switch element on / off time, and the initial value is sent to the primary side switch element control unit 110. Output.

  The primary side switch element control unit 110 controls to turn on the primary side switch element 303 based on the primary side switch element ON time indicated by the initial value, and energizes the primary winding 302a of the boosting transformer 302. Is performed (step S201). Subsequently, the primary side switch element control unit 110 determines whether or not the primary side switch element ON time indicated by the initial value has elapsed (step S202).

  If the primary side switch element ON time has not elapsed (NO in step S202), the primary side switch element control unit 110 continues the on control of the primary side switch element 303. On the other hand, when the primary-side switch element ON time has elapsed (YES in step S202), primary-side switch element control unit 110 controls primary-side switch element 303 to be off, and primary winding of boosting transformer 302 The energization to 302a is stopped (step S203).

  As a result, the energy stored in the boosting transformer 302 is transferred from the secondary winding 302a of the boosting transformer 302 to the secondary side rectifying element 304 in accordance with the energizing current flowing in the primary winding 320a of the boosting transformer 302. To the main capacitor 103. Then, the secondary side discharge time measuring unit 104 starts measuring the secondary side discharge time (step S204).

  The secondary-side release time measuring unit 104 determines whether or not the release of energy from the secondary winding 302a of the boosting transformer 302 to the main capacitor 103 (that is, secondary-side release) has been completed (step S205). . If the secondary side release has not been completed (NO in step S205), the secondary side release time measuring unit 104 continues to measure the secondary side release time.

  When the secondary release is completed (YES in step S205), the secondary release time measuring unit 104 completes the measurement of the secondary release time (step S206). Then, the charging voltage detection unit 105 detects the charging voltage of the main capacitor 103 and gives a charging voltage detection value (also referred to as a detected charging voltage) to the primary-side conduction current peak value calculation unit 106 (step S207).

  Subsequently, the primary-side conduction current peak value calculation unit 106 compares the charge voltage detection value with a predetermined charge voltage completion voltage value to determine whether or not the charge voltage of the main capacitor 103 has reached the predetermined charge completion voltage. Is determined (step S208). When primary side conduction current peak value calculation unit 106 determines that the charging voltage of main capacitor 103 has reached the charging completion voltage (YES in step S208), the primary switch is not shown in FIG. The element control unit 110 turns off the primary side switch element 303 and ends the charge control.

  On the other hand, if the charging voltage of main capacitor 103 has not reached the charging completion voltage (NO in step S208), primary-side energization current peak value calculation unit 106 performs step-up transformer 302 between steps S201 to S203. The peak value I1pk (primary side current peak value) of the energization current flowing through the primary winding 302a is calculated according to the following equation (1) (step S209).

I1pk = (Vmc / Ls) × Ton2 × (Ns / Np) (1)
In Equation (1), I1pk represents the peak current value of the primary winding 302a of the step-up transformer 302, and Vmc represents the charging voltage (charge detection value) of the main capacitor 103. Ls represents the inductance of the secondary winding 302b of the step-up transformer 302, and Ton2 represents the secondary-side emission time. Ns indicates the number of turns of the secondary winding 302b of the boosting transformer 30a, and Np indicates the number of turns of the primary winding 302a of the boosting transformer 302.

  Subsequently, the primary-side switch element on-time calculating unit 107 sets the primary-side conduction current peak value I1pk and the primary-side conduction current peak value setting value set by the primary-side conduction current peak value setting unit 108. Based on the following equation (2), the next on-time Ton1 ′ (calculated on-time) of the primary side switching element 303 is calculated (step S210).

Ton1 ′ = I1set × (Ton1 / I1pk) (2)
In Formula (2), Ton1 ′ indicates the next ON time of the primary side switching element 303, and I1set is the primary side conduction current peak value setting value set by the primary side conduction current peak value setting unit 108. Indicates. Further, Ton1 indicates the current on-time of the primary side switching element 303, and I1pk indicates a current carrying current peak value of the primary winding 302a of the step-up transformer 302.

  Here, the primary-side conduction current peak value set value I1set is set to a value that does not cause magnetic saturation of the core provided in the step-up transformer 302 and does not exceed the rated current of the primary-side switch element 303. This prevents an excessive current from flowing through the primary side switch element 303 and prevents the primary side switch element from being damaged, and the conduction current peak value of the primary side switch element 303 is constant regardless of the power supply voltage. As described above, the on-time of the primary side switch element 303 can be controlled.

  Next, the primary side switch element on / off time setting unit 109 sets the next off time of the primary side switch element 303 based on the secondary side discharge time, and sets the primary switch element on time Ton1 ′ next time. Is set as the ON time of the primary side switching element 303 (step S211). Then, the primary side switch element on / off time setting unit 109 determines whether or not the elapsed time from the secondary side release start in step S203 has passed a preset primary side switch element off time set value. (Step S212).

  If primary side switch element on / off time setting section 109 determines that the elapsed time from the start of secondary side release has not passed the primary side switch element off time set value (NO in step S212). The primary side switch element control unit 110 continues the off control of the primary side switch element 303. If primary switch element on / off time setting section 109 determines that the elapsed time from the start of secondary side discharge has passed the primary switch element off time (YES in step S212), the primary side The switch element control unit 110 returns to the process of step S201 and starts energization on the primary side. At this time, the primary side switch element on / off time set in step S211 is used. And the process from step S201 to S212 is repeated until the charging voltage of the main capacitor 103 reaches the charging completion voltage.

  Thus, in the strobe charging device according to the embodiment of the present invention, the main capacitor 103 is charged according to the primary-side conduction current peak value setting value set by the primary-side switch element conduction current peak value setting unit 108. Therefore, it is possible to prevent the primary side switch element 303 from being damaged due to an excessive current flowing through the primary side switch element 303 to ensure safety, and to shorten the charging time.

  In the above example, the peak value of the conduction current of the primary side switching element 303 is controlled to be constant. For example, the discharge characteristic of the voltage of the power supply 101 (power supply voltage) and the temperature characteristic of the booster circuit 102 are detected. Then, the energization current peak value of the primary side switching element 303 may be adjusted based on the detection result.

  As is apparent from the above description, in the example shown in FIG. 1, the primary side switch element on / off time setting unit 109 and the primary side switch element control unit 110 function as a switch element control unit. Further, the primary side conduction current peak value calculation unit 106 functions as a determination unit.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to these embodiment, Various forms of the range which does not deviate from the summary of this invention are also contained in this invention. .

  For example, the function of the above embodiment may be used as a control method, and this control method may be executed by the charging device. Further, a program having the functions of the above-described embodiments may be used as a control program, and the computer provided in the charging apparatus may be caused to execute the control program. The control program is recorded on a computer-readable recording medium, for example.

  At this time, each of the control method and the control program has at least a charge voltage detection step, a discharge time measurement step, a calculation step, a switch element on-time calculation step, and a switch element control step.

  The present invention can also be realized by executing the following processing. That is, software (program) for realizing the functions of the above-described embodiments is supplied to a system or apparatus via a network or various recording media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 101 Power supply 102 Boost circuit 103 Main capacitor 104 Secondary side discharge time measurement part 105 Charging voltage detection part 106 Primary side conduction current peak value calculation part 107 Primary side switch element ON time calculation part 108 Primary side conduction current peak value setting Part 109 Primary side switch element ON / OFF time setting part 110 Primary side switch element control part

Claims (8)

A step-up transformer having a primary winding and a secondary winding; a switch element connected in series to the primary winding to control energization from a power source to the primary winding; and the secondary winding Energy storage means for storing energy from the step-up transformer, and when the switch element is turned on, the energy stored in the step-up transformer is converted into the secondary winding when the switch element is turned off. A charging device for discharging energy from the wire to the energy storage means,
Charging voltage detecting means for detecting a charging voltage of the energy storage means as a detected charging voltage;
A discharge time measuring means for measuring a time during which energy is discharged from the secondary winding to the energy storage means as a secondary side discharge time;
A current peak value calculating means for calculating a peak value of a current flowing through the primary winding according to the detected charging voltage and the secondary discharge time as a primary current peak value;
Switch element on-time calculation means for calculating an on-time of the switch element as a calculated on-time according to a current peak value set value for setting a peak value of a current flowing through the primary winding and the primary-side current peak value When,
A charging device , comprising: a switch element control unit that performs on / off control of the switch element in accordance with the calculated on-time without measuring a current flowing through the primary winding .   The current peak value calculating means is responsive to the detected charging voltage, the inductance of the secondary winding, the secondary side discharge time, the number of turns of the secondary winding, and the number of turns of the primary winding. The charging device according to claim 1, wherein a primary current peak value is calculated.   The switch element on-time calculating means sets the next on-time of the switch element as the calculated on-time according to the current peak value set value, the current switch element on-time, and the primary current peak value. The charging device according to claim 1, wherein the charging device is calculated. Determining means for determining whether or not charging of the energy storage means is completed based on the detected charging voltage;
The current peak value calculation unit calculates the primary current peak value when the determination unit determines that charging is not completed. 4. The charging device described.   5. The switch element control unit according to claim 1, wherein the switch element controls the switch element so that the primary-side current peak value is constant regardless of the voltage of the power source. 6. The charging device described.   6. The switch element control unit according to any one of claims 1 to 5, wherein the switch element controls on / off of the switch element according to an off time of the switch element obtained based on the secondary emission time. The charging device described in 1. A step-up transformer having a primary winding and a secondary winding; a switch element connected in series to the primary winding to control energization from a power source to the primary winding; and the secondary winding Energy storage means for storing energy from the step-up transformer, and when the switch element is turned on, the energy stored in the step-up transformer is converted into the secondary winding when the switch element is turned off. A method of controlling a charging device that discharges energy from a wire to energy storage means,
A charging voltage detecting step for detecting a charging voltage of the energy storage means as a detected charging voltage;
A discharge time measuring step of measuring a time during which energy is discharged from the secondary winding to the energy storage means as a secondary side discharge time;
A current peak value calculating step of calculating a peak value of a current flowing through the primary winding according to the detected charging voltage and the secondary discharge time as a primary current peak value;
A switch element on-time calculation step of calculating an on-time of the switch element as a calculated on-time according to a current peak value set value for setting a peak value of a current flowing through the primary winding and the primary-side current peak value When,
And a switching element control step of controlling on / off of the switching element according to the calculated on-time without measuring the current flowing through the primary winding . A step-up transformer having a primary winding and a secondary winding; a switch element connected in series to the primary winding to control energization from a power source to the primary winding; and the secondary winding Energy storage means for storing energy from the step-up transformer, and when the switch element is turned on, the energy stored in the step-up transformer is converted into the secondary winding when the switch element is turned off. A control program used in a charging device that discharges energy from a wire to energy storage means,
In the computer provided in the charging device,
A charging voltage detecting step for detecting a charging voltage of the energy storage means as a detected charging voltage;
A discharge time measuring step of measuring a time during which energy is discharged from the secondary winding to the energy storage means as a secondary side discharge time;
A current peak value calculating step of calculating a peak value of a current flowing through the primary winding according to the detected charging voltage and the secondary discharge time as a primary current peak value;
A switch element on-time calculation step of calculating an on-time of the switch element as a calculated on-time according to a current peak value set value for setting a peak value of a current flowing through the primary winding and the primary-side current peak value When,
A control program for executing a switch element control step of performing on / off control of the switch element in accordance with the calculated on-time without measuring a current flowing through the primary winding .

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