CN2416709Y - Electronic ballast - Google Patents

Abstract

The utility model discloses an electronic ballast for HID gas discharge lamp. The circuit board consists of a rectifying filter circuit, a switch circuit, a dynamic adaptation network, a high voltage generating device and the like. The dynamic adaptive network is characterized in that a dynamic adaptive network is arranged between the switching circuit and the load, so that the load can stably work in the impedance change process. The stability of the circuit and the electric energy utilization efficiency are improved.

Description

Electric ballast

The utility model relates to the electric ballast that gaseous discharge lamps such as a kind of high-pressure sodium lamp, Metal halogen lamp, fluorescent lamp are used.

Now, electric ballast has begun on probation in fields such as high-pressure sodium lamp, Metal halogen lamps.It mainly is by power circuit, switching circuit, high-voltage pulse produces compositions such as circuit, its operation principle is: power circuit becomes civil power direct current (also can insert as required power factor (PF) adjust circuit) to convert high-frequency alternating current to through switching circuit through rectifying and wave-filtering to produce circuit (coil) through high-voltage pulse, light gaseous discharge lamp (to call HID in the following text), this electron-like ballast, for example Chinese " electronics newspaper " 99 years the tenth first phases disclosed " high-pressure sodium electronic lamp ballast ", the high-frequency alternating current that switching circuit produces directly produces coil supply HID through high-voltage pulse, and (the high-voltage pulse coil is finished high pressure and is triggered, play the inductor of restriction lamp current behind the HID build-up of luminance), this form, the tube voltage of supplying with HID is all the time less than the output voltage of switching circuit, just there is a problem in this, make HID energy steady operation, just must supply with switching circuit, make switching circuit that higher output voltage be arranged with higher DC power supply voltage.But efficient is reduced, and energy consumption increases.

When using than low dc voltage, owing to HID extinguishes because of internal factor causes the tube voltage fluctuation in the course of the work, can not steady operation.

At the problems referred to above, the purpose of this utility model is to improve the dynamic adaptation of the input impedance of switching circuit output impedance and HID, and a kind of high efficiency is provided, the HID electron rectifier of energy steady operation.

For achieving the above object, solution of the present utility model is: be provided with one and dynamically become the resistance adaptation network in above-mentioned electric ballast, the switching circuit output is connected with HID by this network, eliminate the HID tube voltage and change the phenomenon of extinguishing that causes.

A kind of is an inductance and electric capacity to be connected the back with 7 shapes insert between switching circuit output and the high-voltage pulse coil, and the resonance potential amplitude of utilizing inductance capacitance changes with the impedance of HID, obtains the dynamic adaptation with the HID impedance.Can certainly insert boost type leakage inductance power transformation device between switching circuit and the high-voltage pulse coil, the output voltage that utilizes leakage inductance transformer obtains dynamic adaptation with the characteristic that the impedance of HID becomes.

Owing to adopted the dynamic adaptation network in the above-mentioned solution, thereby can reduce the supply power voltage of switching circuit, and can make the HID steady operation, so circuit efficiency is higher.Can also isolate and reduce the influence of high-voltage pulse switching circuit.

The utility model is described in further detail below in conjunction with accompanying drawing and experimental example:

Figure (1) is the circuit theory diagrams of the utility model first embodiment.

Figure (2) is the circuit theory diagrams of the utility model second embodiment.

Referring to figure (1) D ₁～D ₄And C ₁Form current rectifying and wave filtering circuit, the direct voltage of switching circuit work is provided, switching circuit is by T ₁, T ₂, B, D ₅, C ₂The half-bridge series connection auto-excitation type circuit of forming is by L ₄, C ₃7 fonts of forming dynamically become resistance network and R ₅, D ₆, C ₅, D ₇, L ₆, L ₅The high-voltage pulse circuit of forming, load circuit is by gas discharge lamp HID and capacitance C ₄Form.Civil power is through D ₁-D ₄Rectifying and wave-filtering becomes direct current to supply with by T ₁, T ₂, the switching circuit formed of B, T ₁, T ₂At trigger tube D ₅Exciting under, produce alternate conduction and produce high frequency square wave and output to L ₄With C ₃The resonance of forming becomes the resistance network, because HID this moment does not excite conducting to be equivalent to open circuit, L ₄, C ₃The voltage of output is very high, through R ₅, D ₆Rectification is to C ₅Be charged to silicon two-terminal switch D ₇Breakover voltage, D ₇Produce the tunnel conducting, at L ₆Induce transient magnetic field, L ₅By with L ₆Mutual inductance obtain high-voltage pulse and act on the HID two ends, make it to excite build-up of luminance, the HID conducting, impedance descends, pulling L ₄, C ₃Output voltage descends, C ₅Both end voltage also drops to less than D ₇Breakover voltage and quitting work.L ₄With C ₃Output voltage follow the tracks of the impedance of HID and change.Make switching circuit and HID reach dynamic adaptation, HID can normally stably be worked.

Referring to figure (2), switching circuit adopts parallel connection excitement auto-excitation type half-bridge inversion circuit, and output is connected to leakage inductance boost type transformer B ₂, its course of work is; T ₁With T ₂Be subjected to D ₅The triggering for generating alternate conduction, the output square wave is by L ₄Be coupled to L ₈, through resistance R ₅Be transferred to L ₃, L ₃Coupling L ₁And L ₂Act on T with the positive feedback form ₁, T ₂Form self-oscillation.The switching circuit square wave is through L ₄With L ₇Leakage inductance coupling back output because L ₇On induced voltage can change along with the impedance variation of load, so leakage inductance transformer also has dynamic change resistance ability.Can be fit to adaptive between HID and the switching circuit.This circuit remainder is the same with (1) embodiment.

Claims (3)

1. An electronic ballast is composed of a power supply circuit, a switching circuit, and a high-voltage pulse generating device, and is characterized in that it has a dynamic impedance adaptation network, which is connected to the output end of the switching circuit. 2. The electronic ballast according to claim 1, characterized in that the impedance adaptation network has an inductance connected in series between the output end of the switch circuit and the input end of the load and the high-voltage coil, and is connected in parallel with the load and the high-voltage coil of capacitance. 3. The electronic ballast according to claim 1, characterized in that the impedance adaptation network has a step-up leakage inductance transformer connected between the switching circuit and the load and the high voltage coil.

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