JP2018037136A - Lighting control lighting device including choke transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting control lighting device which does not need to use a conventional switch element of high breakdown voltage performance, but can use a switch element of relatively low breakdown voltage performance, when performing lighting control of a lamp for illumination by phase control.SOLUTION: A lighting control lighting device includes the main winding L1 of a choke transformer 34 connected in series between an AC power supply 10 and a lamp 12, a triac 38 connected in series with the sub-winding L2 of the choke transformer and forming a loop circuit, and a phase control circuit 40 imparting an on/off command for the triac 38 performing phase control of the conduction current i+i'of the main winding L1, by cutting a loop current iflowing through the sub-winding L2 and the triac 38. The phase control circuit 40 is provided to change the on-duty of the triac 38 according to an external input signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to lighting lighting devices such as discharge lamps and LED lamps, and more particularly to a dimming lighting device including a choke transformer.

  In order to realize stepless dimming with a copper-iron type ballast before about 30 years ago, a variable voltage input by a bolt slider is necessary, and such a dimming lighting device has been mainstream. However, a bolt slider more than VA of the ballast that performs dimming is required, and the system is very large.

  In response to this problem, a continuous dimming / lighting device shown in FIG. 4C using phase control has been proposed (for example, Patent Document 1). First, a discharge lamp lighting device as a base will be described with reference to FIG. The lighting device in FIG. 4A includes a lamp 12 and a main choke 14 connected in series to a power supply 10 (for example, 2200 V), and limits the current flowing through the lamp that is lit with alternating current. The main choke 14 is a coil that exhibits a maximum output (for example, 9 kW) alone. In addition, when the choke 14 is used, the lamp current is delayed in phase with respect to the power supply voltage and the primary power factor is lowered. Therefore, the power factor is improved by the power factor improving capacitor 16 connected in parallel to the lamp 12. Here, “choke” refers to a choke coil.

  On the other hand, the two-stage dimming / lighting device of FIG. 4B has a main choke 14 and an additional choke 18 connected in series to the discharge lamp 12, and a bypass switch connected in parallel to the additional choke 18. 20 If the lighting operation is performed with the switch 20 turned on, a current of 8.1 A flows through the switch 20 → the main choke 14, and the lamp 12 is supplied with rated lamp power (1300 V, 9 kW). Further, if the lighting operation is performed with the switch 20 turned off, a current of 5.7 A flows through the additional choke 18 → the main choke 14, and the lamp 12 has a lamp power (1240V, 6 kW) is supplied. In this way, by adding impedance in series with the main choke, it becomes possible to perform two-stage dimming, which is known as a very popular configuration in general lighting circuits.

It can be said that the continuous light control lighting device in FIG. 4C combines the above-described two-stage light control configuration with phase control. That is, in the continuous light control lighting device, instead of the switch 20, a triac (three-terminal semiconductor switch element) 22 is connected in parallel to the additional choke 18. The dimming operation will be described with reference to the waveform diagram of FIG. If the triac 22 is always OFF during lighting, the minimum current (5.7 A) of the waveform i ₁ flows due to the impedance of the two chokes, and the lamp power becomes 6 kW (minimum dimming state). Further, if the triac 22 is always ON, only the impedance of the main choke acts, so that the maximum current (8.1 A) of the waveform i ₂ is obtained and the rated lamp power (9 kW) is supplied to the lamp 12.

Then, the phase control circuit 23 in FIG. 4C repeats the operation of turning off the triac 22 in synchronization with the 0 V phase (zero cross) of the AC power supply and turning it on during the half cycle, thereby adding choke. 18 energization time is controlled (phase control). In FIG. 5, the waveform i ₁ current flows during the OFF period, and the waveform i ₂ current flows during the ON period. By making the ON duty (phase angle (π−φ)) variable, the amount of current flowing through the additional choke 18 can be adjusted, and the lamp current can be changed from the maximum current to the minimum current in an effective value. Dimming is possible between 1 and 2/3 times the lamp power.

JP 05-13189 A (FIG. 1)

  However, in the dimming / lighting device of FIG. 4C, the voltage that the triac 22 opens and closes is the impedance voltage of the dimming additional choke 18, and this additional choke 18 has a high impedance voltage and a relatively large inductance. Indicates. If the triac 22 performs such on / off of the additional choke 18, the surge voltage when the switch is turned off becomes high, and as a result, an expensive triac with high pressure resistance must be used. For example, assuming an 8 kW type UV lamp power supply device (rated 9 kW), the impedance voltage of the additional choke is divided to about 470 V with respect to the AC power supply 2200 V. With regard to the withstand voltage performance of the triac, considering the surge voltage at the OFF time, the 600V withstand voltage product is insufficient, and a triac having a higher withstand voltage performance has to be used.

  The present invention has been made in view of the above problems, and when dimming an illumination lamp by phase control, there is no need to use a switch element having a high withstand voltage performance as in the prior art, and a switch with a relatively low withstand voltage performance. It aims at providing the light control lighting device which can use an element.

  The inventor first examined the dimming lighting device shown in FIGS. 6A and 6B as a derivative type of the conventional phase control system. In the dimming / lighting device of FIG. 6A, a series circuit of an additional choke 28 and a switch 30 is connected in parallel to the main choke 24. If the lighting operation is performed with the switch 30 turned off, a current of 5.7 A flows through the main choke 24 and the lamp 12 is supplied with 2/3 times the rated lamp power (1240 V, 6 kW). When the switch 30 is ON, a current of 5.7 A flows through the main choke 24 and a current of 2.4 A flows through the additional choke 28. Therefore, the lamp 12 has a combined current of 8.1 A. The rated lamp power (1300 V, 9 kW) is supplied. In this way, by adding the currents flowing through the two chokes, the lamp is brightened and two-stage dimming is possible.

In the continuous dimming / lighting device of FIG. 6B, a triac 32 is connected in series to the additional choke 28 instead of the switch 30. Using the waveform diagram of FIG. 6C, if the TRIAC 32 is always OFF by the phase control circuit 33 during lighting, the minimum current (5.7 A) of the waveform i ₁ due to the effect of only the impedance of the main choke 24. And the lamp power becomes 6 kW (minimum dimming state). If the triac 32 is always ON, the maximum current (8.1 A) of the waveform i ₁ + i ₂ obtained by superimposing the waveform i ₁ and the waveform i ₂ is obtained by the action of the impedance of the two chokes, and the lamp 12 Is supplied with rated lamp power (9 kW).

Then, when the triac 32 is operated to control the energization time of the additional choke 28 (phase control), according to the ON duty (phase angle (π−φ)) of the triac 32, as shown in FIG. A current having a waveform i ₁ flows during the OFF period, and a current having a waveform i ₁ + i ₂ flows during the ON period. Therefore, by making the ON duty variable, the lamp current can be changed from the maximum current to the minimum current in an effective value, and dimming between 1 and 2/3 times the rated lamp power becomes possible. Become.

  However, in the dimming / lighting device of FIG. 6B, the impedance voltage of the main choke 24 is divided by about 1500 V with respect to the AC power supply 2200 V, and such a high impedance voltage is also applied to the triac 32. Will be. Therefore, it is considered that such a dimming / lighting device in which two chokes are connected in parallel has not been adopted in the past.

  Here, the inventor paid attention to a technique of adding an additional current by phase control to the current of the main choke as in the phase control method of FIG. If the main choke is composed of the main winding of the transformer and the loop current of the magnetically coupled sub winding is turned on and off by the switch element, the current of the main choke is changed only during the switch ON period. It was found that the additional current due to the mutual inductance of the transformer can be added and the dimming operation by phase control is realized. As a result, it is not necessary to dispose the switch element on the main choke circuit having a high voltage, and the sub-winding composed of the choke having a low impedance voltage and a small inductance can be set as a switching target. If it does so, the surge voltage at the time of switch OFF will also become small, and the switch element of a low pressure | voltage resistant performance can be utilized.

That is, the dimming lighting device according to the present invention is
The main winding (L1) of the choke transformer (34) connected in series between the AC power supply input terminal (P1) and the lamp current output terminal (P2) as shown in FIG.
A semiconductor switching element (38) connected in series to the auxiliary winding (L2) of the choke transformer (34) to form a loop circuit;
Phase control of the conduction current (i ₁ + i ₂ ′) of the main winding (L1) is performed by turning on and off the loop current (i ₂ ) flowing through the sub-winding (L2) and the semiconductor switch element (38). A phase control circuit (40) for giving an on / off command to the semiconductor switch element (38);
Comprising
The phase control circuit (40) is provided so as to change the on-duty of the semiconductor switch element (38) in accordance with an external input signal.

Here, the choke transformer (34) has a tertiary winding (L3), and a detection circuit (44) for detecting a lamp current or a lamp voltage based on an induced electromotive force generated in the tertiary winding (L3). It is preferable to provide.
A discharge lamp (12) is connected to the lamp current output terminal (P2). Alternatively, in FIG. 3, an LED lamp (64) is connected to the lamp current output terminal (P2) via an AC-DC conversion circuit (62).

  According to the above configuration, during phase control, the semiconductor switch element turns on and off the sub winding of the choke transformer that exhibits a low impedance voltage and a small inductance, and the surge voltage when the switch is OFF can be suppressed to a low level. It is possible to provide a phase control type dimming / lighting device using a low-voltage, high-current semiconductor switch element.

The schematic block diagram and operation waveform diagram which show the light control lighting device of 1st embodiment of this invention. It is a figure which shows the specific circuit structure of the said light control lighting apparatus. It is a schematic block diagram which shows the light control lighting apparatus of 2nd embodiment of this invention. Explanatory drawing of the conventional light control lighting apparatus containing the choke transformer connected in series. Explanatory drawing which shows the relationship between the light control operation and current waveform in the apparatus of FIG. Explanatory drawing of the conventional light control lighting apparatus containing the choke transformer connected in parallel.

A circuit configuration and circuit operation of a dimming / lighting device for a discharge lamp according to an embodiment of the present invention will be described with reference to the drawings.
1A includes a main winding (main choke) L1 of a choke transformer 34 and a lamp 12 that are connected in series to an AC power supply 10 (for example, 2200 V), and is lit with an alternating current. The current flowing through the lamp 12 is limited. The main winding L1 is a main choke designed to have, for example, 6 kW output alone at the time of minimum dimming (triac to be described later is always OFF). The choke transformer 34 has a window frame (winding margin) for the auxiliary winding L2, and may have a window frame for the tertiary winding as necessary. A power factor improving capacitor 36 is connected in parallel to the series circuit of the main winding L1 and the lamp 12. A connection point P1 of the capacitor 36 between the power supply 10 and the main winding L1 indicates an AC power supply input terminal, and a connection point P2 between the main winding L1 and the lamp 12 indicates a lamp current output terminal.

A triac 38, which is a semiconductor switching element, is connected in series to the secondary winding L2 of the choke transformer 34, and a loop circuit is formed by the secondary winding L2 and the triac 38. The winding ratio (N2 / N1) of the secondary winding L2 to the primary winding L1 can reduce the voltage generated in the secondary winding L2 to the withstand voltage of the selected triac 38 with respect to the impedance voltage of the primary winding L1. Thus, it is set within the range of approximately 1/5 to 1/10. To the triac 38, given the on / off instruction from the phase control circuit 40, it turns on and off the loop current i ₂ flowing through the auxiliary winding L2 and the triac 38.

The circuit operation will be described with reference to FIG. If brought into lighting operation in a state of being turned OFF triac 38, current _{i 1} of 5.7A flows through the main winding L1, the lighting power of the lamp 12 is 6 kW. Since the current i ₁ flowing through the main winding L1 is an AC waveform, and light up operation in a state of being ON the triac 38, a loop current i ₂ flows through mutual induction in the auxiliary winding L2. Then, due to the mutual inductance of the choke transformer 34, a 2.4 i current i ₂ ′ proportional to the turn ratio (N2 / N1) is added to the main winding L1 having a 6 kW output alone. As a result, a current of 8.1 A (= i ₁ + i ₂ ′ = 5.7 A + 2.4 A) flows through the main winding L1. This current value is a current corresponding to the maximum output 9 kW of the lamp 12. In this way, the lamp 12 can be dimmed in two stages simply by turning on or off the triac provided in the sub-winding L2 of the choke transformer 34. In FIG. 1 (B), the current flowing through the sub-winding L2 differs from the current flowing through the main winding L1, and therefore is shown as a separate graph. 5 is conceptually similar to the waveform of FIG. 5, but conceptually similar to the operation of the derivative circuit of FIG. 6C, the current waveform i _{2 of the} main winding L _{1 is changed} to the current waveform i ₂ by the triac ON. 'Addition is performed.

Further, the phase control operation will be described with reference to the waveform diagram of FIG. If the phase control by the triac 38 is combined with the above-described two-stage dimming configuration, the continuous dimming control of the lamp 12 becomes possible. If the triac 38 is always OFF during lighting, the minimum current (5.7 A) of the waveform i ₁ flows due to the impedance of the main winding L1, and the lamp power becomes 6 kW (minimum dimming state). If the triac 38 is always ON, the mutual inductance of the choke transformer 34 acts and the maximum current (8.1 A) of the waveform i ₁ + i ₂ ′ flows, and the lamp 12 has a rated lamp power (9 kW). Is supplied.

Then, the phase control circuit 40 in FIG. 1A repeats the operation that the triac 34 is turned off in synchronization with the 0 V phase (zero cross) of the AC power supply and is turned on during the half cycle, thereby mutual inductance. The energization time of the additional current i ₂ ′ is controlled (phase control). In FIG. 1B, a current having a waveform i ₁ flows during the OFF period, and a current having a waveform i ₁ + i ₂ ′ flows during the ON period. By making the ON duty (phase angle (π−φ)) variable, the amount of current flowing through the main winding L1 can be adjusted, and the lamp current can be changed from the maximum current to the minimum current in an effective value. Dimming is possible between 1 and 2/3 times the rated lamp power.

Here, for example, when it is desired to select a triac having a withstand voltage of 600V and 30A, the auxiliary winding L2 may be set to the number of turns N2 that generates an electromotive voltage with about 180 to 200V as a guide. Becomes the voltage applied to the triac 38 decreases if less number of turns N2, the current i ₂ for the impedance decreases increases. It is preferable to design the current i ₂ to flow about several tens of A. The details depend on the coupled state of the choke transformer, so it is better to cut and try to reduce the practical number of turns to N2.

FIG. 2 is a specific circuit configuration diagram of the dimming / lighting device of the present embodiment.
The lighting device is connected in order of the step-up transformer 50, the power factor improving capacitor 36, the choke transformer type triac circuit 52, the starting circuit 54, and the lamp 12 from the AC power supply 10 side.

  The phase control circuit 40 is configured to change the on-duty of the triac 38 in accordance with an external input signal from the dimming volume 46. The phase control circuit 40 also includes a detection circuit 42 that detects the power supply voltage of the AC power supply, and a lamp voltage / current detection circuit 44. The detection circuit 44 feeds back the lamp voltage and the lamp current based on the induced electromotive force generated in the tertiary winding L3 provided in the choke transformer 34. In the phase control, the switching timing may be determined based on a detection value selected from the power supply voltage, the lamp voltage, and the lamp current. It is also possible to detect an overcurrent or overvoltage of the lamp 12. For example, when the rectification phenomenon of the lamp occurs, the phase control can be switched to the minimum dimming state, and the rectification phenomenon can be suppressed.

The triac circuit 52 includes a loop circuit including the sub winding L2 of the choke transformer 34 and the triac 38. In this embodiment, a series circuit of a resistor and a capacitor is connected to the triac 38 in parallel. A command signal issued from the output terminal GT of the phase control circuit 40 is applied to the gate of the triac 38 through a resistor.
The dimming volume 46 is a simple dimming instruction volume. In the present embodiment, the dimming volume 46 is constituted by a variable resistor VR, and this variable resistor VR is an element for turning on the trigger element of the gate of the triac 38. When the variable resistor VR is operated, the potential at the connection between the sub-winding L2 and the triac 38 changes, and the on-voltage of the trigger element at the gate of the triac 38 can be adjusted, and the on-duty of the phase control is changed. It is like that.

<Effect of this embodiment>
In the dimming / lighting device of the present embodiment, although the impedance voltage of the main winding L1 of the choke transformer is divided by about 1500V with respect to the AC power supply 2200V, the inductance of the sub winding L2 can be selected to be small. It becomes easy to set the induced voltage generated in the auxiliary winding L2 as small as about 180 to 200 V, and a relatively low impedance voltage is applied to the triac 32. The surge voltage due to the counter electromotive voltage generated in the auxiliary winding L2 is also reduced. As described above, the triac 38 is not arranged in the main circuit, but is arranged in the auxiliary winding L2 by using a magnetically coupled choke transformer. The applied voltage can be matched with the rating (breakdown voltage performance, etc.) of the triac 38. Therefore, the phase control circuit 40 can use a low voltage and large current triac.

When the switch is OFF, the current i ₂ ′ flowing through the main winding L1 disappears, but the current i ₁ flows continuously, so that the surge voltage generated in the main winding L1 is small.

  FIG. 3 is a circuit configuration of a dimming / lighting device for an LED lamp according to the second embodiment of the present invention. AC power from the power supply 10 is supplied to the power supply unit 62 via the choke transformer type triac dimmer 60. In the power supply unit 62, AC-DC conversion is performed on the input power, and a predetermined DC current is supplied to the LED lamp 64.

  As in the triac circuit of the first embodiment, the choke transformer type triac dimmer 60 in FIG. 3 includes a main circuit of the choke transformer and a loop circuit composed of the sub winding and the triac. The conduction current of the main winding is phase-controlled in accordance with the optical signal.

In each of the above-described embodiments, as shown in FIG. 1, the loop circuit formed by connecting the triac 38 in series to the auxiliary winding L2 of the choke transformer has been described as a specific example. As described in the example of FIG. 2, the case where the dimming volume 46 including the variable resistor VR for phase adjustment is used has been described. This variable resistor VR is an element for adjusting the voltage for turning on the trigger element of the gate of the triac 38.
However, as another embodiment, a semiconductor switch element such as an FET can be used instead of the triac, and the FET or the like can be controlled by an IC or a microcomputer. For example, when an analog voltage signal for dimming is input to the microcomputer, the analog voltage value may be adjusted by the dimming volume.

10 AC power supply 12 Lamp (discharge lamp)
34 Choke transformer 36 Power factor improving capacitor 38 Triac (semiconductor switch element)
40 Phase control circuit 42 Power supply voltage detection circuit 44 Lamp voltage / current detection circuit 46 Dimming volume 50 Step-up transformer 52 Choke transformer type triac circuit 54 Start circuit 60 Choke transformer type triac dimmer 62 Power supply unit (AC-DC conversion circuit)
64 LED light emitting device (LED lamp)
i ₂ loop current i ₁ + i ₂ 'conduction current L1 main winding L2 sub winding L3 tertiary winding P1 AC power input P2 lamp current output

Claims (4)

A main winding of a choke transformer connected in series between the AC power supply input terminal and the lamp current output terminal;
A semiconductor switch element connected in series to the sub winding of the choke transformer to form a loop circuit;
A phase control circuit that gives an on / off command to the semiconductor switch element that controls the phase of the conduction current of the main winding by turning on and off a loop current flowing through the sub-winding and the semiconductor switch element;
Comprising
The dimming / lighting device according to claim 1, wherein the phase control circuit is provided so as to change an on-duty of the semiconductor switch element in accordance with an external input signal.   2. The apparatus according to claim 1, wherein the choke transformer has a tertiary winding, and includes a detection circuit that detects a lamp current or a lamp voltage based on an induced electromotive force generated in the tertiary winding. Light lighting device.   3. The dimming / lighting device according to claim 1, wherein a discharge lamp is connected to the lamp current output terminal.   3. The dimming / lighting device according to claim 1, wherein an LED lamp is connected to the lamp current output terminal via an AC-DC conversion circuit.

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