JPH0646598B2 - Discharge lamp lighting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a discharge lamp lighting device using a phase-advancing ballast in which a leakage transformer and a series capacitor are combined, and in particular, a high-voltage discharge with a high starting voltage such as a metal halide lamp. The present invention relates to a discharge lamp lighting device suitable for starting an electric lamp.

[Conventional technology]

BACKGROUND ART A discharge lighting device using a phase-advance type ballast has been widely used in recent years because it has excellent constant power characteristics with respect to fluctuations in power source voltage and extinguishing characteristics.

FIG. 4 is a circuit configuration diagram showing a configuration example of a discharge lamp lighting device using such a phase-advancing ballast. In the figure, 101
Is a leakage transformer, the primary side of which is connected to the power supply 102,
On the secondary side, a parallel circuit of a series main capacitor C _M and its discharge resistance R _H , and a high pressure lamp 103 such as a metal halide lamp.
And are connected in series. And on the lamp 103, SS
Bidirectional two-terminal semiconductor switching element such as S element
Starter is connected in parallel to a series circuit of 104 and a pulse generation capacitor C _P.

Then, in the above-mentioned structure for a discharge lamp lighting apparatus, when the power source 102 is turned on, a sinusoidal voltage is applied to the switching element 104 through the main capacitor C _M, breakover voltage V of the peak value switching element 104 _BO
The switching element 104 is conductive when it exceeds, by stepwise sudden voltage is applied to the pulse generating capacitor C _P, abrupt charging current flows into the capacitor C _P. As a result, a pulse voltage is induced by series resonance with the inductance of the secondary coil of the leakage transformer 101, and the pulse voltage is applied to the lamp 103 to start the lamp 103. And after startup is flowed limited by the capacitive impedance due to the inductance in series with the main capacitor C _M of the secondary coil of the leakage transformer 101, so as to continue lighting.

[Problems to be Solved by the Invention]

By the way, generally, the discharge lamp has a current phase that is easy to start, and if a high-voltage pulse is applied to the discharge lamp at that phase,
It is extremely easy to start. In the case of a phase-advance type ballast using a series capacitor, as shown in FIG. 5, the lamp current Il has a lead phase with respect to the secondary no-load voltage V ₀₂ , and this current Il has a phase (zero crossing). Phase) P ₀ to a phase P ₄₅ delayed by 45 ° with respect to the secondary no-load voltage V ₀₂ waveform, preferably at a phase P _D slightly beyond the phase where the lamp current Il becomes zero, It can be easily started by applying a high voltage pulse. In FIG. 4, Vl represents a lamp voltage waveform.

However, in the conventional discharge lamp lighting device shown in FIG. 4, the breakover voltage V of the switching element 104 is
Due to the size of the _{BO and} the like, the starting pulse can be generated only with a delay phase of 60 ° to 70 ° with respect to the secondary no-load voltage V ₀₂ , and this pulse generation causes the secondary voltage V _02. However, it is difficult to perform the phase advance of the delay phase of about 50 °, and therefore, between the current zero cross phase for easy starting and the phase of 45 ° delay with respect to the secondary voltage V ₀₂ . It is almost impossible to generate a starting pulse at.

Further, since the operating voltage of the switching element cannot be set too high, the pulse voltage generated is not set too high, and therefore it is difficult to reliably and stably start and light a high pressure discharge lamp such as a metal halide lamp having a high starting voltage. It was

The present invention has been made in order to solve the above problems in the conventional discharge lighting device, therefore, in the phase that is easy to start the discharge lamp, to generate a large start pulse pulse energy,
An object of the present invention is to provide a discharge lamp lighting device capable of reliably starting and lighting.

[Means and Actions for Solving the Problems]

In order to solve the above-mentioned problems, the present invention relates to a discharge lamp lighting device in which a lamp is connected and lit through a phase-advancing ballast in which a leakage transformer and a series capacitor are combined with an AC power source, for pulse generation. A half-wave voltage doubler starter consisting of a series circuit of a capacitor and a switching element and a parallel circuit of a diode and a scanning resistor with a charging resistor connected in series is connected in parallel with the lamp. To do.

With this configuration, the generation phase of the starting pulse generated by the operation of the switching element by the output voltage of the half-wave voltage doubler circuit for each cycle of the power supply voltage is sequentially changed as the series capacitor is charged. Transition to advanced phase. This scanning operation of the starting pulse makes it possible to generate the starting pulse in the most favorable phase for lamp starting, and also to add the charging voltage charged in the series capacitor during the half cycle period to the next half cycle voltage. Since the switching element is driven by using the voltage, the pulse height of the generated pulse can be increased, so that stable starting can be reliably performed.

〔Example〕

Examples will be described below. FIG. 1 is a diagram showing a circuit configuration of an embodiment in which the present invention is applied to a discharge lamp lighting device using a phase stabilizer that combines a single-turn leakage transformer and a series capacitor. Reference numeral 1 is a leakage transformer, which is constructed as shown in FIG. That is, the center leg core 2 of the core 2
A gap 3 is formed in a part of a, the primary coil 4 is arranged in the central leg iron core 2a portion where the gap 3 is not provided, and the primary leg core 2a portion where the gap 3 is provided is formed. Is provided with a secondary coil 5. 6
Is a leak core provided in the window of the iron core.

A power supply 7 is connected to the primary side of the leakage transformer 1 configured as described above, and a metal halide lamp is connected to the secondary side via a parallel circuit of a series main capacitor C _M and its discharge resistance R _M. 8 is connected. Between both terminals of the lamp 8, a circuit in which a charging resistor R _c is connected in series to a parallel circuit of a diode D and a scanning resistor R _r , a pulse generating capacitor C _P, and a switching element destruction preventing reactance L _S are connected. A half-wave voltage doubler starter 10 composed of a parallel circuit with a series circuit of a bidirectional two-terminal semiconductor switching element 9 such as an SSS element is connected.

In the discharge lamp lighting device configured as described above, the power source 7
Is charged, the series main capacitor C _M is charged via the charging resistor R _C and the diode D in the positive half cycle. Next, when the negative half-wave is applied, the main capacitor C _M, the pulse generating capacitor C _P, through the breakdown preventing reactance L _S, the switching device 9, the charging voltage of the main capacitor C _M and half-wave When a voltage added with the voltage is applied and the voltage reaches the breakover voltage V _BO of the switching element 9, for example, as shown in FIG. 3, at a phase P _S delayed by 90 ° with respect to the secondary voltage. V _BO
, The switching element 9 becomes conductive in the phase P _S , a charging current flows rapidly in the pulse generating capacitor C _P , and the secondary coil 5 of the leakage transformer 1 and the high voltage pulse V _PS due to resonance action. Occurs.

When the next positive half-wave is applied, the main capacitor C _M is charged again, and when the next negative half-wave is applied,
The switching element 9 is applied with the charging voltage and the half-wave voltage of the main capacitor C _M that has been charged more than when the negative half-wave was applied, and the added voltage is switched in the phase P _C advanced from the phase P _S. The breakover voltage V _BO of the element 9 is reached, and the switching element 9 is turned on at its phase P _C to similarly generate a high voltage pulse V _PC . When a negative half-wave is applied, the charge stored in the main capacitor C _M is discharged through the scanning resistor R _r , but the amount of discharge is smaller than that in the positive half-wave. _M
The charging voltage of will gradually increase.

In the same manner, the main capacitor C _{M is} added every positive half cycle.
Charging progresses and the charging voltage increases, so that the conduction phase of the switching element 9 shifts to the forward advanced phase. Therefore, the starting pulse is generated by shifting to the progressively advanced phase while scanning.

Then, the transition of the pulse generation is stopped at the final phase P _{1 when} the charging of the main capacitor C _M is completed, and the final phase P ₁ is stopped.
The pulse generation is continued until the lamp 8 is started at.

The final pulse generation phase P ₁ depends on how to select the breakover voltage V _BO of the switching element 9 and the scanning resistor R _r.
And the value of the charging resistor R _C , it is possible to easily start the lamp by setting the phase P ₁ at or near the phase that is most easy to start. The scanning resistor R _r and the charging resistor R _r
The scanning speed can also be changed depending on the value of _c .

As described above, the discharge lamp normally starts by the first pulse scanning operation, but it may not start by the first pulse scanning operation for some reason, and even if pulses are continuously generated at the final phase of pulse scanning. Although the discharge lamp cannot be started, it may cause an instantaneous discharge (arcing in the tube) of the discharge lamp.

When in-tube arcing occurs, the charge stored in the main capacitor C _M is completely discharged, so that the pulse scanning operation starts again from the first pulse generation phase. Since the above operation is repeated until the discharge lamp is started, the discharge lamp can be surely started.

The pulse height of the starting pulse generated by the starter 10 is set by the value of the breakover voltage V _BO of the switching element 9, but since the voltage doubler method is adopted, this breakover voltage V _BO is set to a large value. Therefore, a starting pulse with a high pulse height is obtained. The pulse width of the starting pulse is determined by the inductance of the secondary coil of the leakage transformer and the pulse generating capacitor C
_Although it is set by the product of the values of _P , in the present embodiment, since the secondary coil of the leakage transformer 1 is arranged on the iron core provided with the gap, the inductance of the secondary coil can be increased, Therefore, a starting pulse having a wide pulse width and a large energy can be generated while scanning.

Further, in this embodiment, since the leakage transformer in which the iron core at the position of the secondary coil is provided with a gap is used, the waveforms of the secondary short-circuit current and the lamp current are improved and the current quiescent period is eliminated, whereby the lamp is lit. The height of re-ignition voltage rise of each half cycle in the initial stage and the occurrence time are low,
It shortens and can effectively prevent the disappearance and flicker phenomenon.

Further, in the present embodiment, the pulse generating capacitor C _P
Once There charged, may lamp 8 is secondary to start is short-circuited, abrupt discharge current flows from the capacitor C _P pulse generator to the switching elements 9 of the starter 10 in which case the However, the switching element 9 may be damaged, but in this embodiment, since the breakdown preventing reactance L _S is arranged in series with the switching element 9, the short-circuit current is blocked and the switching element 9 is prevented from being damaged. can do.

Although the above-mentioned embodiment shows the one using the single-winding type leakage transformer, the present invention is of course applicable to the one using the semi-multi-winding type or the complete multi-winding type leakage transformer.

Further, in the present embodiment, the present invention is applied to a discharge lamp lighting device using a phase-advancing ballast in which a leakage transformer configured by providing a gap in an iron core at a position where a secondary coil is arranged and a series capacitor are combined. As described above, the present invention is a phase-advancing type ballast in which a series transformer is combined with a leakage transformer having a small local magnetic saturation in which a secondary coil is wound around an iron core forming a narrow magnetic path looser than the lead peak type. The present invention can also be applied to a discharge lamp lighting device using, and it is possible to generate a starting pulse having a wide pulse width while scanning and perform a stable starting.

Further, in the above embodiment, the bidirectional two-terminal semiconductor switching element is used as the switching element forming the starter, but the switching element is S
Elements such as CR and TRIAC can be used, and similar effects can be obtained.

〔The invention's effect〕

As described above based on the embodiment, according to the present invention, a starting pulse having a high pulse height and a large pulse energy is generated while sequentially shifting the generation position for each cycle of the power supply voltage. Therefore, it is possible to reliably and stably start and light the discharge lamp with a pulse having a phase that facilitates starting.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a discharge lamp lighting device according to the present invention, FIG. 2 is a schematic diagram showing the configuration of its leakage transformer, and FIG. 3 is an explanation showing a starting pulse generation mode. FIG. 4 and FIG. 4 are circuit configuration diagrams showing an example of a conventional discharge lamp lighting device, and FIG. 5 is a diagram showing a secondary no-load voltage waveform, a lamp voltage waveform, and a lamp current waveform. In the figure, 1 is a leakage transformer, 3 is a gap, 4 is a primary coil, 5 is a secondary coil, 8 is a lamp, 9 is a switching element, and 10 is a starter.

Claims (1)

[Claims] Claim: What is claimed is: 1. A discharge lamp lighting device in which a lamp is connected through a phase-advancing ballast in which an AC power source is combined with a leakage transformer and a series capacitor to light the lamp, and a series circuit of a pulse generating capacitor and a switching element. , And a half-wave voltage doubler starter consisting of a diode and a scanning resistor connected in parallel with a charging resistor connected in series to the lamp. The discharge lamp lighting device is characterized in that the discharge lamp lighting device is configured to be generated while sequentially shifting.