CN203788534U - Pulse starting circuit of metal halide lamp - Google Patents

Abstract

The utility model relates to a pulse starting circuit of a metal halide lamp, relating to the technical field of metal halide lamp control. The pulse starting circuit is formed by connecting a DC/AC conversion circuit, a PFC circuit, a transformer, a first resistor, a first capacitor, a switch and multiple diodes, the pulse starting circuit is connected to the two ends of the lamp via the transformer and the DC/AC conversion circuit, a parasitic capacitor is connected in parallel with a secondary coil of the transformer, and an auxiliary inductor is connected between a primary coil of the transformer and the switch. According to the utility model, the auxiliary inductor is added into a traditional starting circuit and the parasitic capacitor of the transformer is fully utilized to generate two different frequencies of igniting pulse sequences and simultaneously add the pulse sequences to the two ends of the lamp, thereby providing a pulse voltage peak which is sufficiently high, ensuring sufficient pulse width, and effectively improving the igniting reliability; the auxiliary inductor can effectively limit current peaks of the circuits, and overcome fluctuation of the pulse voltage peak caused by discreteness of the parasitic capacitor; and the pulse starting circuit is simple in structure and very high in practicality.

Description

A kind of Metal halogen lamp pulse starting circuit

Technical field

The utility model relates to Metal halogen lamp control technology field, especially a kind of Metal halogen lamp pulse starting circuit.

Background technology

Along with popularizing of Green Lighting Project, metal halide lamp (that is: Metal halogen lamp) causes that high light flux, high light efficiency, color rendering are good, long-life and the advantage such as discharge tube is little, aspect the illuminations such as road, exhibition room, market, is being widely applied.

Metal halogen lamp due to self negative resistance charactertistic and start and require must mate ballast and jointly use; At present, the main Starting mode of electric ballast has two kinds: LCC resonance Starting mode and pulse transformer Starting mode; Wherein, when when pulse transformer Starting mode has load open circuit, no current in loop, open circuit start to main circuit switch pipe without advantages such as impacts, it needs special start-up circuit, but the peak impulse voltage that start-up circuit provides is little, pulse duration is narrow, easily reduces the reliability of igniting; The circuit structure of LCC resonance Starting mode is simple, control flexibly, can start frequency by software change, change starting resistor and adapt to different object lamps, but that shortcoming is loop start electric current in the time of load open circuit is large to facilitate.For the electric ballast of high-frequency lighting, resonance Starting mode is proper, but for low power metallic halogen lamp, easily produces acoustic resonance phenomenon, so generally adopt pulse transforming Starting mode.

Therefore, be necessary traditional pulse transforming start-up circuit to carry out circuit structure improvement.

Utility model content

For above-mentioned the deficiencies in the prior art, the purpose of this utility model be to provide a kind of circuit structure simply, not only enough large peak impulse voltage can be provided but also can ensure enough pulse durations, effectively improve the Metal halogen lamp pulse starting circuit of igniting reliability.

To achieve these goals, the utility model adopts following technical scheme:

A kind of Metal halogen lamp pulse starting circuit, it comprises the pulse starting circuit being formed by connecting by DC/AC change-over circuit, pfc circuit, transformer, the first resistance, the first electric capacity, switch member and several diodes, described pulse starting circuit is connected to the two ends of lamp body by transformer and DC/AC change-over circuit, on the secondary coil of described transformer, be parallel with parasitic capacitance, between the primary coil of described transformer and switch member, be connected with auxiliary induction.

Owing to having adopted such scheme, the utility model by adding auxiliary induction and making full use of the parasitic capacitance of transformer in traditional pulse starting circuit, the firing pulse sequence that generates two groups of different frequencies is added to lamp body two ends simultaneously, enough large peak impulse voltage both can be provided, can ensure again enough pulse durations, effectively improve igniting reliability; Meanwhile, effectively limit circuit current peak overcome the fluctuation of the caused crest value of impulse voltage of parasitic capacitance discreteness of auxiliary induction; Its circuit structure is simple, has very strong practicality.

Brief description of the drawings

Fig. 1 is the circuit structure diagram of the utility model embodiment;

Fig. 2 is the equivalent electric circuit of Fig. 1 discharge loop.

Embodiment

Below in conjunction with accompanying drawing, embodiment of the present utility model is elaborated, but the multitude of different ways that the utility model can be defined by the claims and cover is implemented.

As depicted in figs. 1 and 2, the Metal halogen lamp pulse starting circuit of the present embodiment, it comprises that (diode of the present embodiment amounts to two by DC/AC change-over circuit, pfc circuit, transformer T, the first resistance R, the first capacitor C, switch member S and several diodes, i.e. the first diode D1 and the second diode D2) pulse starting circuit that is formed by connecting, pulse starting circuit is connected to the two ends of lamp body L by transformer T and DC/AC change-over circuit; Wherein, after the secondary coil series connection lamp body L of transformer T, be connected to DC/AC change-over circuit, tandem tap part S between the primary coil of transformer T and earth terminal, switch member S is parallel with the second diode D2, between the second diode D2 and pfc circuit unit, be connected the first diode D1, after the first resistance R and the series connection of the first capacitor C and pfc circuit unit is in parallel, simultaneously, on the secondary coil of transformer T, be parallel with parasitic capacitance Cs, between the primary coil of transformer T and switch member S, be connected with auxiliary induction L1.As shown in Figure 1 and in conjunction with Fig. 2 and Fig. 3, in the time that switch member S turn-offs, the first capacitor C 1 energy storage is charged to pfc circuit; When switch member S conducting, the former limit inductance L p that transformer T primary side produces and auxiliary induction L1 and the first capacitor C 1 form basic resonant tank, then by transformer T secondarily level a coil produce required high pressure, utilize high-voltage pulse to be added on lamp body L.

For further illustrating the superiority that increases auxiliary induction L1, can carry out correlation computations according to Fig. 2, Fig. 2 is the reduced graph of the discharge loop that is derived according to Fig. 1, wherein La be the leakage inductance of transformer T and auxiliary induction L1 and, Lp is the magnetizing inductance of the primary side of transformer T, Rp is the conductor resistance of transformer T primary coil, and Lks is the leakage inductance of the second coil side of transformer T, and Rs is the conductor resistance of the secondary coil of transformer T.Voltage and current relation by loop is set up equation group, as follows:

$L_p\frac{{\mathrm{di}}_{L_p}}{\mathrm{dt}}-L_a{C}_1\frac{{{\mathrm{du}}_{C_1}}^2}{d^{2}t}-u_{C_1}=0---\left(1\right)$

$C_1\frac{{\mathrm{du}}_{C_1}}{\mathrm{dt}}=i_{L_p}+C_m{L}_p\frac{d^2{i}_{L_P}}{{\mathrm{dt}}^2}---\left(2\right)$

If

$P=\frac{(L_P{C}_1+L_a{C}_1+L_P{C}_m)-\sqrt{{(L_P{C}_1+L_a{C}_1+L_P{C}_m)}^2-4L_P{L}_a{C}_1{C}_m}}{2L_P{L}_a{C}_1{C}_m}---\left(3\right)$

$Q=\frac{(L_P{C}_1+L_a{C}_1+L_P{C}_m)+\sqrt{{(L_P{C}_1+L_a{C}_1+L_P{C}_m)}^2-4L_P{L}_a{C}_1{C}_m}}{2L_P{L}_a{C}_1{C}_m}---\left(4\right)$

And then voltage and the loop current of trying to achieve the second coil side of transformer T are:

$\begin{array}{c}{u}_0\left(t\right)=\frac{{\mathrm{NL}}_P{C}_1{u}_{C_1}\left(0\right)}{\sqrt{{(L_P{C}_1+L_a{C}_1+L_P{C}_m)}^2-4L_P{L}_a{C}_1{C}_m}}\\ \×(\cos \sqrt{P}t-\cos \sqrt{Q}t)\end{array}---\left(5\right)$

$i_{L_u}\left(t\right)=\frac{C_1{u}_{C_1}\left(0\right)}{\sqrt{{(L_P{C}_1+L_u{C}_1+L_P{C}_m)}^2-4L_P{L}_u{C}_1{C}_m}}$

$\begin{array}{c}{i}_{L_u}\left(t\right)=\frac{C_1{u}_{C_1}\left(0\right)}{\sqrt{{(L_P{C}_1+L_a{C}_1+L_P{C}_m)}^2-4L_P{L}_a{C}_1{C}_m}}\\ \×((\frac{1}{\sqrt{P}}-L_P{C}_m\sqrt{P})\sin \sqrt{P}t-(\frac{1}{\sqrt{Q}}-L_P{C}_m\sqrt{Q})\sin \sqrt{Q}t)\end{array}---\left(6\right)$

From formula (5), when increasing after auxiliary induction L1, output voltage comprises two frequencies, and high frequency frequency is by formula (4) decision, and Frequency is determined by formula (3).The high voltage pulse of two groups of different frequencies produces simultaneously, carries out synchronized oscillation, synchronous fading, can produce significant energy gain effect, and required energy when increasing lamp body L1 and starting, improves the reliability of igniting.

The foregoing is only preferred embodiment of the present utility model; not thereby limit the scope of the claims of the present utility model; every equivalent structure or conversion of equivalent flow process that utilizes the utility model specification and accompanying drawing content to do; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.

Claims (1)

1. a Metal halogen lamp pulse starting circuit, it comprises the pulse starting circuit being formed by connecting by DC/AC change-over circuit, pfc circuit, transformer, the first resistance, the first electric capacity, switch member and several diodes, described pulse starting circuit is connected to the two ends of lamp body by transformer and DC/AC change-over circuit, on the secondary coil of described transformer, be parallel with parasitic capacitance, it is characterized in that: between the primary coil of described transformer and switch member, be connected with auxiliary induction.