JPS61245494A - Discharge lamp lighting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention has a high-frequency power circuit unit and a lighting fixture including a discharge lamp installed separately, so that even when the number of fixtures connected to the high-frequency power circuit unit changes, The present invention relates to a discharge lamp lighting device that controls so that a rated current always flows through the discharge lamp of each lighting device.

[Background technology]

Discharge lamps, especially low-pressure discharge lamps such as fluorescent lamps, reach their maximum luminous efficiency when lit at a high frequency of several tens of KHz.
It is well known that the efficiency of lighting devices can be improved and the devices can be made smaller and lighter.
In order to shorten the length and increase the flexibility of the fixture, the high-frequency power circuit section is placed separately, and only the discharge lamp, stabilizing element, and preheating circuit are housed in the lighting fixture, and multiple units are connected in parallel to form a single unit. There is a method of lighting multiple lights by supplying power from one high-frequency power supply circuit, but in this method, harmonics flow when there is waveform distortion, increasing power loss in the wiring. A series circuit of a reactance element and a capacitance element is provided on the output side of the conversion circuit (inverter circuit) to remove harmonics. In addition, this capacitance element has a filter effect and also has a power factor improvement effect, which means that the maximum number of lighting fixtures can be connected to the high-frequency power supply, and all lighting fixtures can be equipped with discharge lamps. It also has the function of passing a leading phase current that compensates for the slow phase current that flows through each lighting device (the current flowing to the discharge lamp and the current flowing to the primary winding of the preheating transformer) in a state where multiple lights are lit. When the number of lamps changes, the capacitance of the capacitance element must also change according to the changed lamp current, otherwise the output voltage will change, and as a result, the lamp current will change.Regarding this problem, The output voltage and current at each number of lamps are detected to control the conduction phase angle of the input current, or a variable inductance element is provided in parallel with the capacitance element and the inductance is controlled so that the output voltage becomes the rated voltage. I have to.

However, this method is set so that the rated voltage is reached only when the number of lamps changes, and does not take into account the effect of the primary current of the preheating transformer when the lighting equipment is removed. There is a problem that the lamp current does not reach the rated current when the lamp is removed.

FIGS. 4A and 4B show circuit diagrams of a discharge lamp lighting device that is the basis of the present invention. This discharge lamp lighting device connects a full-wave rectifier 2 to an AC power supply 1, and connects a constant current chiller coil CH to the positive output terminal of the full-wave rectifier 2 via a Cyrisk 5CR2.

One end of the is connected. A series circuit of resistor R1 and thyristor SCR is connected to both ends of this thyristor 5CR2,
The anode of the thyristor 5CR2 is connected to the gate of the thyristor SCR via a resistor R2. The constant current choke coil CH.

The other end is connected to the intermediate terminal of the primary winding n1 of the oscillation transformer Tl, and both terminals of the primary winding n1 of the oscillation transformer T1 are connected to each other via a capacitor C1, and each is connected to a switching transistor Ql.

3 of the zero oscillation transformer TI which is connected to the collector of Q2, and which connects the emitters of the switching transistors Ql and Q2 to each other and connects to the negative terminal of the full-wave rectifier 2.
Both ends of the next winding n3 are connected to switching transistors Q
The bases are connected to each other through resistors R3 and R, and a DC power supply is connected between the connection point of both resistors R3 and R4 and the negative output terminal of the gold wave rectifier 2. A series circuit of a reactance element CH2 and a capacitance element C2 is connected to both ends of the secondary winding n2 of the zero oscillation transformer T connected to E, and a series circuit of a reactance element CH2 and a capacitance element C2 is connected in parallel to both output ends of the capacitance element C2 for output voltage detection. A primary winding n1 of the transformer T2 is connected, and one end of the primary winding n1 of the output current detecting current transformer CT is connected to one end of the primary winding n1 of the output voltage detecting transformer T2. The circuits up to this point together with the number of lights control circuit CR, which will be described later, constitute a high frequency power supply circuit section l. In addition, the circuit IN surrounded by a dashed-dotted line constitutes a high frequency conversion circuit IN, the circuit DT surrounded by a dashed-dotted line constitutes an output voltage/current detection circuit, and the circuit IV surrounded by a dashed-double line constitutes an inverter. There is. Terminal T at the other end of the primary winding n1 of the output voltage detection transformer T2
M, and the terminal TM2 at the other end of the primary winding n1 of the current transformer CT for detecting the output current are connected to a series circuit (lighting equipment , ■') are connected in parallel, and the primary winding nl of the preheating transformer T3゜Ta2 is connected to both ends of each discharge lamp 4. .4
′ is connected to the filament. The secondary winding n2 of the output voltage detection transformer T2 is a lamp number control circuit CR.
connected to the full-wave rectifier 6, with resistors R13,
A series circuit of R11 is connected, and a smoothing capacitor C5 is connected to both ends of the resistor R11. The secondary winding n2 of the current transformer CT for output current detection is connected to the full-wave rectifier 5,
A series circuit of resistors R12 and RIG is connected to its output terminal, and a smoothing capacitor C4 is connected to both ends of the resistor RIO. Then, resistors RII + R10 are connected in series so that the voltage direction of the output current detection voltage VRIO is opposite to the output voltage detection voltage vR, and the resistors R11 and R10 are connected in series.
The combined voltage from IO is applied to the gate of programmable unijunction transistor PUT via resistor R9. In addition, there are resistors R6 and R at both ends of the thyristor SCR.
6 in series, connect the connection point of resistors R5 and R6 to the base of transistor Q3, connect its emitter to the cathode of thyristor SCR, connect its collector to the base of transistor Q4, and connect the collector of transistor Q4. A capacitor C3 is connected between the transistor Q4 and the emitter, and the collector of the transistor Q4 is connected to the anode of the programmable unijunction transistor PUT.

Then, the cathode of the programmable unijunction transistor PUT is connected to the primary winding n of the pulse transformer PT.
1 through transistor Q3. Connected to the emitter of Q4. Below, these transistors Q3. Q.

Let the potential of the emitter of be the negative line.

The negative output end of the full wave rectifier 6 is connected to the minus line, and a resistor R1 is connected from the positive output end of the full wave rectifier 6.
4 through the Zener diode ZD.

and connect its anode to the cathode of transistor Q5.
The emitter of transistor Q is connected to the negative line and connected to the base via resistor R16. The collector of transistor Q is connected to the gate of thyristor SCR+. Also, the cathode of the Zener diode ZDI is connected to the negative line via a capacitor C6, and each resistor R? , R, and the transistor Q3. It is connected to the collector of Q.

Next, the operation of this discharge lamp lighting device will be explained.

After the power is turned on, a gate current is applied to thyristor 5CRI via resistor R2, thyristor 5CR1 becomes conductive, and an input voltage is applied to inverter IV via resistor R1.
Inverter IV starts oscillating. When the inverter v oscillates, a detection voltage is generated in the secondary winding n2 of the output voltage detection transformer T2, which is rectified by the full-wave rectifier 6 and charged to the capacitor C6 by the time constant of the resistor R14 and capacitor C6. When the charging voltage exceeds the Zener voltage of the Zener diode ZD, a base current flows through the transistor Q5, which becomes conductive, and the thyristor SCR
, and the thyristor SCR is turned off. By turning off thyristor S'CR, thyristor SCR.

A voltage is generated every half cycle across the resistor Rs.
, R6 detect the partial voltage, transistor Q3 is turned on, transistor Q4 is turned off, and capacitor C3 is charged at a constant time constant (within half a commercial cycle). On the other hand, a composite voltage of the voltage detected from the output voltage and the output current is applied to the gate of the programmable unijunction transistor PUT via the resistor R9, and on the other hand, when the charging voltage of the capacitor C3 becomes high, the programmable unijunction transistor PUT becomes conductive, current flows through the primary winding n1 of the pulse transformer PT, and a pulse signal is applied to the gate of the thyristor 5CR2, making it conductive.

In this conventional example, the difference voltage between the applied detection voltages VRII and VRIO is adjusted as the gate voltage of the programmable unijunction transistor PUT so that the optimum voltage can be obtained from the output current and output voltage for each number of lamps. A pair of terminals TM,,T depending on the change in the number of lights.
The voltage appearing between M2 is simply controlled so that the rated current always flows through each discharge lamp 4, 4', and the current in the primary winding n1 of the preheating transformer T3 ( There was a problem in that the lamp current was not compensated for due to changes in the slow phase current.

The reason why the lamp current changes as the number of lamps changes is as follows. That is, the oscillation period of inverter IV is determined by capacitor C1 and oscillation transformer T! It is determined by the resonant frequency with the inductance component of the load as seen from the primary winding +11 side, so if the number of lamps is reduced due to thinning lighting or failure at the end of the discharge lamp life, the inductance component of the load increases and the frequency increases. Since the output current decreases and the voltage drop at reactance element CH2 decreases,
This is because the output voltage of the inverter v increases.

[Purpose of the invention]

This invention allows a predetermined lamp current to flow through each discharge lamp regardless of the number of discharge lamps connected to the high-frequency power source, and also allows each discharge lamp to flow regardless of the number of lighting devices connected to the high-frequency power source. An object of the present invention is to provide a discharge lamp lighting device that can flow a predetermined lamp current.

[Disclosure of the invention]

A discharge lamp lighting device of the present invention includes a high-frequency power supply unit and a plurality of lighting fixtures connected in parallel to an output end of the high-frequency power supply unit, and each of the plurality of lighting fixtures includes a discharge lamp and a plurality of lighting fixtures connected in parallel to an output end of the high-frequency power supply unit. a stabilizing element that limits a lamp current flowing through the discharge lamp; a preheating circuit that supplies a preheating current to the discharge lamp; and a first capacitance element that is connected in parallel to the preheating circuit and compensates for the current that flows through the preheating circuit. The high-frequency power supply section includes: a high-frequency conversion circuit that converts a DC voltage into a high-frequency voltage; a series circuit of a reactance element and a second capacitance element connected to the output end of the high-frequency conversion circuit; A pair of output terminals provided at both ends of the capacitance element to supply power to the plurality of lighting fixtures, and an output voltage appearing between the pair of output terminals is detected and supplied to the plurality of lighting fixtures from the pair of output terminals. An output voltage/current detection circuit that detects the output current, and a discharge voltage that appears between the pair of output terminals in accordance with the number of discharge lamps connected between the pair of output terminals based on the output of the output voltage/current detection circuit. This configuration includes a number-of-lights control circuit that controls the output voltage.

In this way, the output voltage appearing between a pair of output terminals and the output current supplied from a pair of terminals to multiple lighting fixtures are detected by an output voltage/current detection circuit, and based on the output of this output voltage/current detection circuit, Since the output voltage appearing between the pair of output terminals is controlled in accordance with the number of discharge lamps connected between the pair of output terminals, each A predetermined lamp current can be passed through the discharge lamp, making it possible to perform thinning lighting.

In addition, since each lighting fixture is provided with a first capacitance element that is connected in parallel to the preheating circuit and compensates for the current flowing through the preheating circuit, when the lighting fixture is removed and the current in the preheating circuit disappears, the first capacitance element is connected in parallel to the preheating circuit. There is also no compensation current flowing through the capacitance element, so the presence or absence of current in the preheating circuit does not affect the high frequency power supply section, and even if the number of connected lighting equipment changes, it will not change depending on the difference in the number of discharge lamps mentioned above. A predetermined current can be passed through each discharge lamp simply by controlling the voltage. As a result, an arbitrary number of lighting fixtures can be connected to the high frequency power supply unit within a range that does not exceed the maximum number of lighting fixtures.

Note that by providing the first capacitance element in parallel with the preheating circuit, the capacitance of the second capacitance element is reduced.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. This discharge lamp lighting device has a configuration as shown in FIG.
Output voltage/current detection circuit DT.

The light number control circuit CR) is the same as in FIGS. 4A and 4B. The difference is that a capacitance element 'C7IC7' for current compensation is connected in parallel to the series circuit of a stabilizing element 3.3' such as a current limiting choke coil and a discharge lamp 4.4'. As shown in FIG. 2, the capacitance of this capacitance element C7 is such that a current IC7 whose absolute value is about the same and whose phase is 180° different from the current IL flowing through the stability element 3 and the primary winding n1 of the preheating transformer T3 flows through the current IL. eVc2, which is set to a value that allows , is the voltage across the capacitance element C2, and is equal to the voltage v2.

The operation of the capacitance element C7 will be explained with reference to FIG. In the same figure, the solid line indicates the state where all the lights are on, vl
is the output voltage of the high frequency conversion circuit IN, and 2 is the output voltage of the high frequency power supply circuit I. vL^ is the lamp current flowing through the discharge lamp 4, IL is the current flowing through the preheating transformer T3, and Ic is the capacitance element C2, C? is the sum of the currents flowing in . Vt is the voltage across reactance element CH2, and VL(
LA) is the voltage component due to lamp current IL^, VL (
C) is a capacitance element c2. This is the voltage component due to the current flowing through C.

Now, if only the number of lamps decreases and the lamp current flowing through the lamps decreases from ILA to ILA', then the lamp current IL
The voltage across reactance element CH2 due to A' is VL
(LA) to VL' (LA), and as a result, the composite voltage Vt with voltage VL (C) is VL'
(VL'<VL), voltage (1) becomes Vt'(Vt'<Vt) due to the relationship with voltage v2.

Here, since the voltage V1 is always constant, the voltage v2 increases, but for this effect, the number of lights control circuit C
R works to step down v2 by phase control etc. and make it the rated output.

Next, if the number of appliances changes, the voltage V.

The process up to (LA) is the same as when the number of lamps changes, but if there was no capacitance element C7, the current IL in the primary winding n1 of the preheating transformer T3 would have decreased, but this would have been compensated for. The leading phase current rc+ increases and the current 1c becomes ■c', so that i' V L (C) becomes V
L (C) ' (Vt (C) '>VL (
C)), and as a result, the voltage ■L' becomes ■L',
The voltage y,+ becomes v,' (V, "<vl ')," where v1=constant, so the voltage v2 becomes even larger.

However, in this embodiment, when the lighting fixture I is removed, the capacitance element C7 for compensating the current IL in the primary winding of the preheating transformer T3 is also removed, and the phase-advanced current IC+ that was compensating for the current IL is also reduced. , VL (C) does not change, and as a result, the voltages v and I also do not change. Therefore, the rated output voltage can be obtained only by controlling the number of lights control circuit CR, regardless of the number of connected lighting fixtures n and n'. The lamp current is constantly adjusted to the rated current.

〔Effect of the invention〕

The discharge lamp lighting device of the present invention detects the output voltage appearing between a pair of output terminals and the output current supplied from the pair of terminals to a plurality of lighting equipment with an output voltage/current detection circuit,
This output voltage/current detection circuit controls the output voltage appearing between the pair of output terminals in accordance with the number of discharge lamps connected between the pair of output terminals based on the output. A predetermined lamp current can be passed through each discharge lamp regardless of the number of discharge lamps connected to the lamp, and thinning lighting is possible.

In addition, since each lighting fixture is provided with a first capacitance element that is connected in parallel to the preheating circuit and compensates for the current flowing through the preheating circuit, when the lighting fixture is removed and the current in the preheating circuit disappears, the first capacitance element is connected in parallel to the preheating circuit. There is also no compensation current flowing through the capacitance element, so the presence or absence of current in the preheating circuit does not affect the high frequency power supply section, and even if the number of connected lighting equipment changes, it will not change depending on the difference in the number of discharge lamps mentioned above. A predetermined current can be passed through each discharge lamp simply by controlling the voltage. As a result, an arbitrary number of lighting fixtures can be connected to the high frequency power supply unit within a range that does not exceed the maximum number of lighting fixtures.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a discharge lamp lighting device according to an embodiment of the present invention, FIGS. 2 and 3 are voltage and current vector diagrams of each part,
FIGS. 4A and 4B are circuit diagrams of a discharge lamp lighting device that is the basis of the present invention. ■...High frequency power supply section, n, n'...Lighting equipment, IN
...High frequency conversion circuit, CR...Light number control circuit, DT
...output voltage/current detection circuit, CH2...reactance element, C2...capacitance element (second),
4゜4'...discharge lamp, 3,3'...stability element, T3
．． T3'... Preheating transformer, C7, C7'... Capacitance element (first)

Claims (1)

[Scope of Claims] A high-frequency power supply unit and a plurality of lighting fixtures connected in parallel to the output end of the high-frequency power supply unit, each of the plurality of lighting fixtures including a discharge lamp and a discharge lamp connected to the discharge lamp. The lamp comprises a stabilizing element that limits the flowing lamp current, a preheating circuit that supplies a preheating current to the discharge lamp, and a first capacitance element that is connected in parallel to the preheating circuit and compensates for the current that flows through the preheating circuit. , the high-frequency power supply section includes a high-frequency conversion circuit that converts a DC voltage into a high-frequency voltage, a series circuit of a reactance element and a second capacitance element connected to the output terminal of the high-frequency conversion circuit, and a series circuit of the second capacitance element. A pair of output terminals provided at both ends to supply power to the plurality of lighting fixtures, and detecting an output voltage appearing between the pair of output terminals and detecting an output current supplied to the plurality of lighting fixtures from the pair of output terminals. An output voltage/current detection circuit to be detected, and an output voltage appearing between the pair of output terminals corresponding to the number of discharge lamps connected between the pair of output terminals based on the output of the output voltage/current detection circuit. A discharge lamp lighting device equipped with a lamp number control circuit.