CN2788507Y

CN2788507Y - High-performance daylight lamp electronic ballast

Info

Publication number: CN2788507Y
Application number: CN 200520007616
Authority: CN
Inventors: 王孚望; 沈汉意
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-03-04
Filing date: 2005-03-04
Publication date: 2006-06-14
Anticipated expiration: 2015-03-04

Abstract

The utility model relates to an electronic ballast, particularly an electronic ballast of a high-performance daylight lamp. The utility model comprises a rectifying circuit (1), a filter circuit (2), an oscillation-starting triggering circuit (3), a half-bridge inverting circuit and an output resonance circuit, wherein the half-bridge inverting circuit and the output resonance circuit are driven by a transformer. The utility model is characterized in that two symmetrical high-frequency choking coils (L2 and L3) are arranged between the rectifying circuit (1) and the filter circuit (2), and the high-frequency choking coils (L2 and L3) are isolated from the filter circuit (2) through diodes (D5 and D6). Thus, odd harmonic is effectively suppressed, power factor is raised, total harmonic THD is always made to be smaller than 20 percent and the power factor is raised to be more than 0.98.

Description

The high-performance electronic ballast for fluorescent lamp

Technical field

The utility model relates to electric ballast, especially a kind of high-performance electronic ballast for fluorescent lamp.

Background technology

At present, high performance sight lamp electronic ballast adopts Active Power Factor Correction (PFC) circuit usually, use special chip, generally the line power factor can be brought up to more than 0.95, input current total harmonic distortion degree (THD) is reduced to below 10%, but its price is also higher usually, is difficult for being accepted by general marketplace.Therefore; most of electronic ballast for fluorescent lamp adopts passive pfc circuit on the domestic market; wherein use the most generally by the stream filter circuit; its operation principle is based on reducing output dc voltage; in each half period; the time that AC-input voltage is higher than VD is elongated; the angle of flow of rectifier diode just can increase; exchange input current like this and chase supply voltage transient change track; the power factor of circuit can be brought up to more than 0.9; power supply total harmonic distortion degree THD is reduced to below 30%; China's utility model patent " a kind of electric ballast " (Granted publication number: CN2648763Y; Granted publication day: on October 13rd, 2004; the patent No.: 03210546.0) disclose a kind of electric ballast that adopts modified model to pursue the stream filter circuit; China's utility model patent " a kind of High Power Factor high-performance electronic ballast " (Granted publication number: CN 2617119Y; Granted publication day: on May 19th, 2004, the patent No.: 03216800.4) also disclose the electric ballast that a kind of employing is pursued the stream filter circuit and had abnormity protection circuit.

But the defective by the stream filter circuit also is clearly, because the pulsation composition of high direct voltage is very big, makes the crest of lamp current bigger than (CCF), causes fluorescent tube to descend useful life.

Summary of the invention

It is simple that the purpose of this utility model provides a kind of circuit, with low cost, has the high-performance electronic ballast for fluorescent lamp of high power factor and low lamp current crest ratio.

The technical solution of the utility model is:

A kind of high-performance electronic ballast for fluorescent lamp, the half-bridge inversion circuit and the output resonant circuit that comprise rectification circuit, filter circuit, starting of oscillation circuits for triggering, drive by transformer, its special feature is, between rectification circuit and filter circuit, be provided with two high frequency choke coil L2, L3 of symmetry, these two high frequency choke coil L2, L3 isolate by diode D5, D6 and filter circuit respectively, thereby effectively suppress odd harmonic and improve power factor.

Wherein rectification circuit comprises the bridge rectifier be made up of diode D1, D2, D3, D4 and the capacitor C 2 in parallel with this bridge rectifier, filter circuit is the electrochemical capacitor C3 in parallel with this bridge rectifier, the positive output end of rectification circuit links to each other with the positive pole of diode D5 by high frequency choke coil L2, the negative pole of this diode D5 links to each other with the positive pole of electrochemical capacitor C3, the negative output terminal of rectification circuit links to each other with the negative pole of diode D6 by high frequency choke coil L3, and the positive pole of this diode D6 links to each other with the negative pole of electrochemical capacitor C3.

Wherein the starting of oscillation circuits for triggering comprise resistance R 6, capacitor C 7 and bidirectional trigger diode D13, the end of this bidirectional trigger diode D13 links to each other with the base stage of the switching tube Q2 that constitutes half-bridge inversion circuit, and its other end links to each other with the negative pole of electrochemical capacitor C3 by capacitor C 7 respectively and links to each other with the filament of fluorescent lamp by resistance R 6.

Also comprise abnormal state protection circuit; this circuit comprises inductance L 5; diode D15; resistance R 7; R8; electrochemical capacitor C9; zener diode D14; capacitor C 8; with controllable silicon DB32; inductance L 5 and constitute inductance L 6 conjugation of output resonant circuit wherein; when abnormality appears in circuit; the output loop electric current increases; inductance L 5 will induce electromotive force; through diode D15 rectification; resistance R 8; the R7 dividing potential drop; with after the electrochemical capacitor C9 filtering by voltage stabilizing didoe D14 to capacitor C 8 charging; controllable silicon DB32 conducting when reaching the triggering level of controllable silicon DB32; the base stage that makes the switching tube Q1 that constitutes half-bridge inversion circuit makes the circuit failure of oscillations by diode D12 and controllable silicon DB32 discharge thereby cause base potential to reduce.

Wherein before rectification circuit, also be connected with anti-emi filter.

The utlity model has following characteristics:

1, input circuit adopts the two inductance High frequency filters of symmetric form to add the diode isolation behind rectification output end, has effectively suppressed harmonic wave, has improved power factor, has reduced lamp current crest ratio;

2, improved starting of oscillation circuits for triggering and increased abnormal state protection circuit, if the filament open circuit, then not starting of oscillation of half-bridge inversion circuit; if filament is rubescent, can't light then controllable silicon conducting; the switching tube failure of oscillations, thus promptly the half-bridge inversion circuit failure of oscillation enters guard mode.

Description of drawings

Accompanying drawing 1 is circuit theory diagrams of the present utility model.

Embodiment

Come the utility model is described in further detail below in conjunction with circuit theory diagrams:

As shown in Figure 1, the utility model comprises rectification circuit 1, filter circuit 2, starting of oscillation circuits for triggering 3, half-bridge inversion circuit by the transformer driving, and output resonant circuit, between rectification circuit 1 and filter circuit 2, be provided with two high frequency choke coil L2 of symmetry, L3, these two high frequency choke coil L2, L3 is respectively by diode D5, D6 and filter circuit 2 are isolated, thereby effectively suppress odd harmonic, can make total harmonic wave THD＜20%, because the high frequency choke coil has certain phase shift effect, played the function of passive pfc circuit, therefore can improve more than the power factor to 0.98.

As shown in Figure 1, rectification circuit 1 comprises the bridge rectifier be made up of diode D1, D2, D3, D4 and the capacitor C 2 in parallel with this bridge rectifier, filter circuit 2 is high-pressure electrolysis capacitor C 3 in parallel with this bridge rectifier, the positive output end of rectification circuit 1 links to each other with the positive pole of diode D5 by high frequency choke coil L2, the negative pole of this diode D5 links to each other with the positive pole of electrochemical capacitor C3, the negative output terminal of rectification circuit 1 links to each other with the negative pole of diode D6 by high frequency choke coil L3, and the positive pole of this diode D6 links to each other with the negative pole of electrochemical capacitor C3.

As shown in Figure 1, starting of oscillation circuits for triggering 3 comprise resistance R 6, capacitor C 7, with bidirectional trigger diode D13, the end of this bidirectional trigger diode D13 links to each other with the base stage of the switching tube Q2 that constitutes half-bridge inversion circuit, its other end links to each other with the negative pole of electrochemical capacitor C3 by capacitor C 7 respectively and links to each other with the filament of fluorescent lamp by resistance R 6, in existing electric ballast, normally resistance is linked to each other with dc output end behind the rectifying and wave-filtering, charge to electric capacity by resistance during startup, reach bidirectional trigger diode conducting after the triggering level, the half-bridge inversion circuit starting of oscillation, and in the utility model, resistance R 6 is directly linked to each other with the filament of fluorescent lamp, if filament open circuit, then capacitor C 7 can't be charged, and half-bridge inversion circuit also just can not starting of oscillation.

As shown in Figure 1; the utility model also comprises abnormal state protection circuit 4; this circuit comprises inductance L 5; diode D15; resistance R 7; R8; electrochemical capacitor C9; zener diode D14; capacitor C 8; with controllable silicon DB32; inductance L 5 and constitute inductance L 6 conjugation of output resonant circuit wherein; when abnormality appears in circuit; the output loop electric current increases; corresponding inductance L 5 will induce electromotive force; through diode D15 rectification; resistance R 8; the R7 dividing potential drop; with after the electrochemical capacitor C9 filtering by voltage stabilizing didoe D14 to capacitor C 8 charging; controllable silicon DB32 conducting when reaching the triggering level of controllable silicon DB32; the base stage that makes the switching tube Q1 that constitutes half-bridge inversion circuit makes the circuit failure of oscillations by diode D12 and controllable silicon DB32 discharge thereby cause base potential to reduce.

As shown in Figure 1, before rectification circuit 1, also be connected with anti-emi filter 5, can effectively suppress the high-frequency interferencing signal in the electrical network.

Claims

1, a kind of high-performance electronic ballast for fluorescent lamp, the half-bridge inversion circuit and the output resonant circuit that comprise rectification circuit (1), filter circuit (2), starting of oscillation circuits for triggering (3), drive by transformer, it is characterized in that: two the high frequency choke coils (L2, L3) that between rectification circuit (1) and filter circuit (2), are provided with symmetry, these two high frequency choke coils (L2, L3) are isolated by diode (D5, D6) and filter circuit (2) respectively, thereby effectively suppress odd harmonic and improve power factor.

2, high-performance electronic ballast for fluorescent lamp as claimed in claim 1, it is characterized in that: wherein rectification circuit (1) comprises by diode (D1, D2, D3, D4) bridge rectifier of Zu Chenging and the electric capacity (C2) in parallel with this bridge rectifier, filter circuit (2) is the electrochemical capacitor (C3) in parallel with this bridge rectifier, the positive output end of rectification circuit (1) links to each other with the positive pole of diode (D5) by high frequency choke coil (L2), the negative pole of this diode (D5) links to each other with the positive pole of electrochemical capacitor (C3), the negative output terminal of rectification circuit (1) links to each other with the negative pole of diode (D6) by high frequency choke coil (L3), and the positive pole of this diode (D6) links to each other with the negative pole of electrochemical capacitor (C3).

3, high-performance electronic ballast for fluorescent lamp as claimed in claim 1 or 2, it is characterized in that: wherein starting of oscillation circuits for triggering (3) comprise resistance (R6), electric capacity (C7) and bidirectional trigger diode (D13), one end of this bidirectional trigger diode (D13) links to each other with the base stage of the switching tube (Q2) that constitutes half-bridge inversion circuit, and its other end links to each other with the negative pole of electrochemical capacitor (C3) by electric capacity (C7) respectively and links to each other with the filament of fluorescent lamp by resistance (R6).

4; high-performance electronic ballast for fluorescent lamp as claimed in claim 1 or 2; it is characterized in that: also comprise abnormal state protection circuit (4); this circuit comprises inductance (L5); diode (D15); resistance (R7; R8); electrochemical capacitor (C9); zener diode (D14); electric capacity (C8); and controllable silicon (DB32); inductance (L5) and constitute inductance (L6) conjugation of output resonant circuit wherein; when abnormality appears in circuit; the output loop electric current increases; inductance (L5) will induce electromotive force; through diode (D15) rectification; resistance (R8; R7) dividing potential drop; and charge to electric capacity (C8) by voltage stabilizing didoe (D14) after electrochemical capacitor (C9) filtering; controllable silicon (DB32) conducting when reaching the triggering level of controllable silicon (DB32); the base stage that makes the switching tube (Q1) that constitutes half-bridge inversion circuit makes the circuit failure of oscillations by diode (D12) and controllable silicon (DB32) discharge thereby cause base potential to reduce.

5, high-performance electronic ballast for fluorescent lamp as claimed in claim 1 or 2 is characterized in that: wherein also be connected with anti-emi filter (5) before at rectification circuit (1).