JP3085004B2 - Discharge lamp lighting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device.

[0002]

2. Description of the Related Art Conventional lighting devices for discharge lamps include:
As shown in FIG. 5, the chopper circuit 4 and the inverter circuit 5
A circuit that shares a switching element is known.
Thus, the input power factor of the voltage input to the discharge lamp 6 is increased, and the harmonic components are reduced.

The circuit configuration of the above-described conventional discharge lamp lighting device will be described. Inverter circuit 5 includes transistors 50 and 51 connected in series and transistor 5
Diodes 50 connected in anti-parallel to 0 and 51, respectively.
a, 51a, a series circuit of capacitors 52, 53, and feedback windings 54ca, 5 for driving the transistors 50, 51.
4cb, the output winding 54b connected to the discharge lamp 6
And the connection point of the transistors 50 and 51 and the capacitor 5
A transformer 54 having a primary winding 54a connected between the connection points 2 and 53, and resistors 55, 56, 57 and 58
It is composed of The chopper circuit 4 is connected to the AC power supply 1 via the noise filter 2 and the rectifier circuit 3, and is connected between the smoothing capacitor 41, the transistor 50, and the output terminal of the transistor 50 and the rectifier circuit 3. And a diode 51a for flowing a charging current from the connection point between the inductance element 42 and the transistor 50 to the smoothing capacitor 41 (JP-A-3-276598).

Next, the operation of the above circuit will be described. When a full-wave rectified DC pulsating voltage is applied to the chopper circuit 4 from the AC power supply 1 via the noise filter 2 and the rectifier circuit 3, the inductance element 42 is added to the smoothing capacitor 41.
Is charged through the diode 51a. For example, resistor 5
A start-up current flows through 6 to turn on the transistor 50. When the transistor 50 is turned on, the smoothing capacitor 4
1 flows through the capacitor 53 and the transformer 54a, and the transformer 54 of the inverter circuit 5 and the capacitor 5a.
The resonance system composed of 2, 53 starts to vibrate. for that reason,
A voltage is generated in the feedback windings 54ca and 54cb of the transformer 54 so that the transistor 50 is turned on and the transistor 51 is turned off, the transistor 50 is kept on, and the transistors 50 and 51 are turned on and off with the vibration of the resonance system. Is alternately repeated. When the transistor 50 is on,
A current limited by the inductance element 42 flows from the AC power supply 1 via the inductance element 42, and this current increases with time. In addition, this current, and
The current flowing from the smoothing capacitor 41 via the resonance system simultaneously flows into the transistor 50, and this current increases with time. Next, when the transistor 50 is turned off, the energy stored in the inductance element 42 immediately before the turn-off is discharged to the smoothing capacitor 41 via the diode 51a. At the same time, when the transistor 50 is turned off, the transistor 51 is turned on, the resonance system continues to oscillate, and continues to supply voltage and energy to the discharge lamp 6. Due to the vibration of the resonance system, the transistor 5
1 turns off and the transistor 50 turns on. Thereafter, the chopper circuit 4 and the inverter circuit 5 repeat the above operation,
The discharge lamp 6 is kept on.

In this operation, when the instantaneous value of the AC power supply 1 is low, the rate of increase of the current flowing through the inductance element 42 is low.
The energy stored in the inductance element 42 at the time of turn-off of 0 is small, and the charging voltage of the smoothing capacitor 41 also decreases. At this time, the input current also decreases according to the instantaneous value of the AC power supply 1. When the instantaneous value of the AC power supply 1 is high, an operation opposite to that when the instantaneous value is low is performed. That is, the increase rate of the current flowing through the inductance element 42 is high,
If the ON time is always the same, the energy stored in the inductance element 42 when the transistor 50 is turned off is large, and the charging voltage of the smoothing capacitor 41 increases. The input current also increases according to the instantaneous value of the AC power supply 1. Therefore, an input current having a substantially similar shape to the waveform of the AC power supply 1 can be obtained, the power input power factor can be increased, and harmonic components of the power supply input current can be reduced.

[0006]

However, such a conventional discharge lamp lighting device requires an inductance element 42 in addition to the transformer 54a of the inverter circuit 5, so that the entire circuit becomes large. Further, since all the voltage of the AC power supply 1 is applied to the inductance element 42 and it is necessary to limit the inductance element 42 to a predetermined input current, the inductance element 42 itself becomes larger and more expensive. Also, since the voltage of the smoothing capacitor 41 becomes proportional to the voltage of the AC power supply 1 as the transformer 54 of the inverter circuit 5,
The voltage ripple becomes large, and a voltage large enough to apply a large resonance voltage to the moment of the large voltage ripple is required, and there is a problem that the whole circuit becomes large.

An object of the present invention is to provide a discharge lamp lighting device capable of starting and maintaining a discharge lamp in a state having a small input, a simple configuration, a high input power factor, and a low harmonic component of a power supply input current. It is.

[0008]

SUMMARY OF THE INVENTION A discharge lamp lighting device according to the present invention comprises a series body of a discharge lamp and a resonance capacitor, a smoothing capacitor connected to one end of the series body, and a second end connected to the other end of the series body. And a closed circuit of a switch element connected to the other end of the smoothing capacitor, a connection point between the inductance element and the switch element, and a connection point between the smoothing capacitor and the series body. A rectifier is connected between the rectifier and the output end of a rectifier circuit to be connected to an AC power supply at a connection point between the smoothing capacitor and the switch element and a connection point between the series body and the inductance element. Having a configuration.

[0009]

According to the present invention, the discharge lamp, the resonance capacitor, the smoothing capacitor, the inductance element, and the switch element form a closed circuit, and the rectifier circuit, the inductance element of the inverter circuit, and the switch element form a closed circuit. By using the inductance element for the chopper operation and the inverter operation for a part of time and a part of current value, both the charging operation of the smoothing capacitor and the lighting operation of the discharge lamp interfere with each other. At this time, the current due to the inverter operation acts as a chopper operation in the direction of suppressing the power supply input current proportional to the instantaneous power supply voltage value flowing through the inductance element. At the same time, since the current due to the chopper operation is proportional to the instantaneous value of the power supply input voltage, it suppresses the low-frequency ripple of the discharge lamp current flowing through the inductance element and acts as a current suppressing element of the discharge lamp current itself. . Therefore, the charging operation of the smoothing capacitor and the lighting operation of the discharge lamp assist each other, thereby reducing the load on the inductance element, increasing the power input power factor, reducing the harmonic components of the power input current, and Thus, the discharge lamp current ripple is improved.

[0010]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the discharge lamp lighting device according to the embodiment of the present invention comprises a series body of a fluorescent lamp 80 as a discharge lamp and a resonance capacitor 72, and a smoothing capacitor 79 connected to one end of the series body. A closed circuit of an inductance element 73 connected to the other end of the series body, and a transistor 70 connected to the other end of the smoothing capacitor 79,
A diode 71a is connected between a connection point between the inductance element 73 and the transistor 70 and a connection point between the smoothing capacitor 79 and the series body, and a connection point between the smoothing capacitor 79 and the transistor 70, and the series body and the inductance element 73. Rectifier circuit 3 to be connected to the AC power source at the connection point with
Output terminals are connected respectively.

An AC power supply 1, a fluorescent lamp 80, a smoothing capacitor 79, a resonant capacitor 72 connected in series to the fluorescent lamp 80, and a transistor 7 as a switch element.
0, 71 and the fluorescent lamp 80 connected to the transistor 70
The DC input from the smoothing capacitor 79 is converted to AC using the LC resonance generated by the on / off operation of the transistors 70 and 71, that is, the resonance generated by the inductance element and the capacitor. An inverter circuit 7 for supplying the fluorescent lamp 80, and a rectifying circuit 3 for rectifying the AC power supply voltage
A current transformer 74 connected between the transistor 70 of the inverter circuit 7 and a diode 71a as a rectifier connected between the transistor 70 and the smoothing capacitor 79; , And a filter circuit 2 connected between the inverter circuit 7 and the AC power supply 1. One of the output terminals of the rectifier circuit 3 is connected to one end of the inductance element 73, and the other is connected to the emitter of the transistor 70 via the resistor 77. The other end of the inductance element 73 is connected to the collector of the transistor 70 via the primary winding 74a of the current transformer. That is, the rectifier circuit 3, the inductance element 73, and the primary winding 74 of the current transformer.
a, the transistor 70, and the resistor 77b form a closed circuit. The inverter circuit 7 includes a transistor 71 having a resistor 77a connected to the emitter and a transistor 70 having a resistor 77b connected to the emitter, forming a series circuit. A smoothing capacitor 79 is connected in parallel with the series circuit. Resistors 77a and 77b and transistors 70 and 7
1 and the diodes 70a, 71a
Are connected in anti-parallel, respectively, and the diode 71 a is connected in parallel with the capacitor 78. In addition, a resonance capacitor 7 is connected to a series circuit of the transistor 71 and the resistor 77a.
2, a fluorescent lamp 80, an inductance element 73, and a primary circuit 74a of a current transformer are connected in series, and a capacitor 81 is connected in parallel via a preheating electrode of the fluorescent lamp 80. Further, the drive control means 9 includes:
A resistor 75a is connected between the output terminal of the secondary winding 74b of the current transformer 74 and the base of the transistor 71 having the resistor 77a connected to the emitter.
A resistor 75b is connected between the output terminal of the next winding 74c and the base of the transistor 70 having a resistor 77b connected to the emitter. A diode 76a is connected between the base of the transistor 71 and the resistor 77a toward the base, a diode 76b is connected between the base of the transistor 70 and the resistor 77b toward the base, and is connected in parallel with the capacitor 23 of the filter circuit 2. Is connected to the base of the transistor 70 via a trigger element 84 from a connection point of the series circuit. The filter circuit 2 includes an AC power supply 1
, A capacitor 21 is connected in parallel to the output terminal of the rectifier circuit 3, and an inductance 22 is connected in series. A diode 24 is connected in series to the output terminal in the forward direction. A capacitor 23 is connected between the output terminal of the rectifier circuit 3 and the other end.

Next, the operation of such a discharge lamp lighting device will be described. Before the fluorescent lamp 80 is started, a pulsating voltage is generated from the AC power supply 1 at one output terminal of the filter circuit 2. The current due to this pulsating voltage flows to the next closed circuit. That is, one output terminal of the rectifier circuit 3 → the inductance element 73 → the current transformer 74 → the diode 71
a → smoothing capacitor 79 → flows from the other output terminal of the rectifier circuit 3 to charge the smoothing capacitor 79 up to the peak value of the power supply voltage. At the same time, due to the charging current, an output is generated in the secondary winding 74c of the current transformer 74, and the transistor 7
Supply a base current of zero. At the same time, when the capacitor 85 is charged via the resistor 82 and the voltage reaches the breakdown voltage of the trigger element 84, the charge of the capacitor 85 is supplied to the base of the transistor 70, and the transistor 70 is turned on. When the transistor 70 is turned on, the initial voltage of the smoothing capacitor 79 is lower than the voltage of the AC power supply 1, so that the inductance element 73, the current transformer 74, and the AC power supply 1 are further passed through the rectifier circuit 3 and the filter circuit 2. The current flows through the transistor 70 while increasing. Next, when the core of the current transformer 74 is magnetically saturated by the current flowing through the primary winding 74a of the current transformer 74, the output of the secondary winding 74c is lost, and the base current supplied to the transistor 70 cannot be supplied. The voltage of the resistor 77b through which the emitter current 70 flows also rises, and this voltage is applied in the reverse direction between the base and the emitter of the transistor 70, and the transistor 70 is turned off. Immediately before the transistor 70 is turned off, the inductance element 73 is turned off.
The energy stored in the current transformer 74
Is discharged to the smoothing capacitor 79 via the diode 77a. Due to this step-up chopper operation, the voltage of the smoothing capacitor 79 becomes higher than the output voltage of the rectifier circuit 3. At the same time, since the current of the inductance element 73 decreases with time, the output polarities of the secondary windings 74b and 74c are inverted, and the transistor 71 is turned on and the transistor 70 is turned off. When this current decreases, the operation of the trigger element 84 again causes the transistor 70 to operate.
Turns on.

Next, when the transistor 70 is turned on again, the output voltage of the rectifier circuit 3 and the filter circuit 2 is initially lower than the voltage charged in the smoothing capacitor 79 at this time, so that the diode 24 is turned off. Flowing through the inductance element 73 from the smoothing capacitor 79 to the resonance capacitor 72, the preheating electrode of the fluorescent lamp 80, the capacitor 81, the inductance element 73, the primary winding 74a of the current transformer, the transistor 70, and the resistor 77b.
Is the current flowing through This current is applied to the fluorescent lamp 8
Flow through the 0 preheating electrode to heat the electrode. As the capacitor 81 is charged by this current, the diode 24
When the cathode potential of the diode 24 decreases below the anode potential of the diode 24, the diode 24 turns on,
A current flows from the AC power supply 1. At this time, the current flowing through the inductance element 73 keeps continuity, and the impedance of the capacitor 81 is sufficiently larger than the input impedance including the filter circuit 2, so that the current flowing through the inductance element 73 is rapidly smoothed. The current from the capacitor 79 is replaced with the current from the AC power supply 1. That is, during the ON period of the transistor 70 until the current transformer 74 switches at a substantially constant current value to turn off the transistor 70, the preheating electrode of the fluorescent lamp 80 is heated, and the inductance is obtained immediately before the transistor 70 is turned off. Most of the current flowing through the element 73 can be replaced with the current I ₂ from the AC power supply 1 from the electrode heating current. Therefore, the energy stored in the inductance element 73 can boost the voltage of the smoothing capacitor 79 to a sufficiently large voltage according to the turn-off of the transistor 70. At the same time, during the next ON period of the transistor 71, the inductance element 73 and the capacitors 72, 81 due to the energy stored in the capacitors 72, 81, which are generated immediately after the diode 24 is turned off due to the decrease in the energy discharge of the inductance element 73. Due to the resonance, a large voltage is applied to the fluorescent lamp 80, and a large preheating current also flows to the preheating electrode. By repeating such an operation, the fluorescent lamp 80 is turned on with an increase in the electrode temperature.

Next, when the fluorescent lamp 80 is lit,
The circuit operation will be described. When the transistor 70 turns on,
At this time, the voltage charged in the smoothing capacitor 79 is
Output voltage of the rectifier circuit 3 and the filter circuit 2
Initially, the voltage of the inductance element 73 is sufficiently low.
High voltage due to the current flowing from the smoothing capacitor 79
The diode 24 is off. That is,
What flows to the inductance element 73 is a smoothing capacitor
From 79, the preheating power of the resonance capacitor 72 and the fluorescent lamp 80
And the preheating electrodes of the capacitor 81 and the fluorescent lamp 80
Inductor 73 and primary winding of current transformer
Flows through transistor 74a, transistor 70 and resistor 77b
Current I₁(The power supply voltage V in FIG.₁<
Voltage V of inductance element 73_TwoCurrent I during the period₁).
This current I₁Is the resonance capacitor 72 and the inductance
A resonance current with the element 73 is formed. This current I₁By
As the resonant capacitor 72 is charged, the diode
24, the cathode potential of the diode 24 decreases.
The anode potential is lower than the instantaneous value of the AC power supply 1
And the diode 24 turns on, and the AC power supply 1
Current I_TwoFlows in. At this time,
Current I_TwoIndicates that the current flowing through the inductance element 73 is continuous.
The function of maintaining the continuity and the resonance capacitor 72
The impedance of the fluorescent lamp 80 and the capacitor 81 and the
Filter circuit for the voltage value of the
Input impedance and power supply voltage instant including 2
Rapidly changes and smooths to a value determined by the ratio to the value
Current I from capacitor 79₁From the AC power supply 1
Current I_Two(In FIG. 2 (b),
Source voltage V₁> Voltage V of inductance element 73_TwoOf period
Current I_Two). That is, the current transformer 74 is magnetically saturated.
The switching at almost constant current value
Transistor 70 until transistor 70 is turned off.
When the current of the fluorescent lamp 80 is supplied during the ON period,
Before turning off transistor 70, the inductor
The current flowing through the sensing element 73 is
_TwoCan be partially replaced with a current value. That
Therefore, when the transistor 70 is turned off,
Of the energy stored in the
_TwoThe energy of the smoothing capacitor 79 can be supplied by the component
You. Also, the current I flowing simultaneously₁Ingredients, fluorescent run
Can be maintained at a constant level. Transis
When the transistor 70 is off and the transistor 71 is on,
As the energy discharge of the conductance element 73 decreases,
As the charging current to the smoothing capacitor 79 decreases,
The resonance between the capacitor 72 and the inductance element 73 is maintained.
To maintain the discharge of the fluorescent lamp 80 at a certain level.
Can be. And to repeat such operation
As a result, the fluorescent lamp 80 can be kept lit and smooth.
The voltage of the capacitor 79 can be maintained.

In such a starting / lighting operation, when the instantaneous value of the AC power supply 1 is low (the hatched portion in FIG. 2A), as shown in FIG. 2B, the power supply voltage V ₁ < period the voltage V ₂ of the inductance element 73 becomes longer and the period of the current I ₂ flowing from the AC power supply 1 to the inductor 73 is short, and the current I ₂ this current I ₂ is proportional to the power supply input voltage instantaneous value Is also smaller. That is, the current I ₁ through the fluorescent lamp 80 due to the inverter operation suppresses the current I ₂ flowing from the AC power supply 1 to the inductance element 73 as a chopper operation in terms of time and current value, and the current I _{1 of the} fluorescent lamp 80. Can be reduced.

On the other hand, when the instantaneous value of the AC power supply 1 is high (the hatched portion in FIG. 3A), the power supply voltage V ₁ > the voltage V ₂ of the inductance element 73 as shown in FIG. 3B. period is long, the period of the current I ₂ flowing from the AC power supply 1 to the inductor element 73 is long, and the current I ₂ this current is proportional to the power input voltage instantaneous value is increased. That is, in this case, the fluorescent lamp 8 by the inverter operation is used.
Current I ₁ through 0, the AC power supply 1 as a chopper operation
Temporally current inhibits the rate of current I ₂ flowing through the inductance element 73 from the smaller.

[0018] In such an operation, looking for one cycle of the AC power source 1, as shown in FIG. 4 (a), the input current I _s is a waveform V _s of the AC power supply 1 and substantially similar shape, The power input power factor is high, and harmonic components of the power input current can be reduced.

Further, looking at the current I ₁ of the fluorescent lamp 80, when the voltage instantaneous value of the AC power source 1 is low, the resonance current I ₁ is then kept large, when the voltage instantaneous value of the AC power supply 1 is high, The resonance current I ₁ is suppressed by the input current I _{2, and} the current I ₁ of the fluorescent lamp 80 is made substantially constant in one cycle of the AC power supply 1 as shown in FIG. As a result, the lamp current ripple is reduced, and the fluorescent lamp 80 can always have a substantially constant tube wall load, so that instantaneous overload of the phosphor, electrode, and tube wall can be reduced, and the lamp life can be improved. Further, since the lamp current ripple is small, the capacitance of the smoothing capacitor 79 can be reduced, and the stability of the inverter circuit 7 with respect to the power supply voltage and load can be improved. Further, as shown in FIG. 4C, the current flowing through the inductance element 73 is a current I ₂ from the AC power supply 1 (FIG. 4A) and a current I ₁ from the smoothing capacitor 79 (FIG. 4B). ) Is added. Current flowing through the inductance element 73 is divided and operates as the current I ₁ from the current I ₂ and the smoothing capacitor 79 some time, and mutually partially current suppressed from the AC power supply 1 As a result, the same performance as the conventional one can be obtained by using one inductance element, which has conventionally required two inductance elements for the chopper circuit and the inverter circuit. Need not be limited by a single inductance component, the inductance value of the inductance element 73 can be set smaller than in the past, so that the inductance element 73 does not increase in size, and the circuit configuration can be simplified, inexpensive, and compact.

Also, the AC power supply 1 supplies the current transformer 7
4, the smoothing capacitor 79 can be charged first, so that the first transistor 70 can be easily turned on, and in particular, the circuit starting performance at low temperatures can be improved.

As described above, in the discharge lamp lighting device according to the embodiment of the present invention, the fluorescent lamp 80, the resonance capacitor 72, the smoothing capacitor 79, the inductance element 73, and the transistor 70 constitute a closed circuit, and the rectifier circuit 3 and the inverter By forming a closed circuit with the inductance element 73 of the circuit 7 and the transistor 70, the inductance element 7
3 is used for the chopper operation and the inverter operation in part of the time and part of the current value, so that both the charging operation of the smoothing capacitor 79 and the fluorescent lamp lighting operation interfere with each other. At this time, the current by the inverter operation acts as a chopper operation in a direction to suppress the power supply input current proportional to the instantaneous value of the power supply voltage flowing through the inductance element 73.
At the same time, since the current due to the chopper operation is proportional to the instantaneous value of the power supply input voltage, it suppresses the low-frequency ripple of the discharge lamp current flowing through the inductance element 73 and acts as a current suppressing element of the discharge lamp current itself. Will be.

As described above, the charging operation and the discharge lamp lighting operation of the smoothing capacitor 73 assist each other, thereby reducing the load on the inductance element 73, increasing the power input power factor, and reducing the harmonic components of the power input current. The state can be improved, and the current ripple of the discharge lamp 80 can be improved.

As an example, in the circuit configuration shown in FIG. 1, the inductance element 73 is 1.2 mH, the resonance capacitor 72 is 0.022 μF, and the capacitor 81 is 2200.
pF smoothing capacitor 79 is 10 μF, AC power supply voltage 12
When the experiment was carried out using each of them at 0 V, it was found that 15 W
TOTAL HARM, which can start and maintain a fluorescent lamp, has an input power factor of 99%, and is a sum of harmonics to a fundamental wave
Good results with ONIC DISTORTION of 10% or less were obtained.

In the above embodiment, the drive control means 9 is of a self-excited type by the current transformer 74 because the circuit can be minimized. However, another type may be used. Although the switching elements 70 and 71 are bipolar transistors, FETs or the like may be used. In this case, a diode with a built-in FET can be used as the diodes 71a and 70a. Also in the case of the present embodiment, the base-collector PN junctions of the transistors 71 and 70 may be diodes 71a and 70a. Further, the filter circuit 2 may have another configuration as long as it smoothes the chopper operation current and reduces noise. In this embodiment, a series inverter is used as the inverter circuit configuration. However, any other inverter circuit using resonance can obtain the same effect, and a single inverter circuit can also obtain the same effect.

[0025]

As described above, the discharge lamp lighting device of the present invention has a small, inexpensive, and simple configuration, has a high power input power factor, and discharges in a state where the harmonic components of the power input current are small. The lamp can be started and lit.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a discharge lamp lighting device according to an embodiment of the present invention.

2A is a waveform diagram of a power supply voltage. FIG. 2B is a waveform diagram of a current and a voltage of an inductance element when an instantaneous value of an AC power supply voltage is low.

3A is a waveform diagram of a power supply voltage. FIG. 3B is a waveform diagram of a current and a voltage of an inductance element when an instantaneous value of an AC power supply voltage is high.

FIG. 4 is a diagram showing an input current, a lamp current, and a current waveform of an inductance element in one cycle of an AC power supply.

FIG. 5 is a circuit diagram of a conventional discharge lamp lighting device.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 3 Rectifier circuit 50, 51, 70, 71 Transistor 41, 79 Smoothing capacitor 72 Resonant capacitor 73 Inductance element

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-197086 (JP, A) JP-A-64-84592 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05B 41/282 H02M 7/48 H05B 41/24

Claims (1)

(57) [Claims] 1. A series body of a discharge lamp and a resonance capacitor, a smoothing capacitor connected to one end of the series body,
An inductance element connected to the other end of the series body,
A switching circuit connected to the other end of the smoothing capacitor; anda rectifier between a connection point between the inductance element and the switch element and a connection point between the smoothing capacitor and the series body. Discharging, wherein a connection point between the smoothing capacitor and the switch element and an output terminal of a rectifier circuit to be connected to an AC power supply are connected to a connection point between the series body and the inductance element, respectively. Lamp lighting device.