CN1090119A - Have the protector for abnormal condition high power factor electronic lamp - Google Patents

Abstract

Have the protector for abnormal condition high power factor electronic lamp, belong to glow discharge spot lamp, comprise fluorescent tube, housing and electric ballast.The major technique feature is ac power input end varistor MYG in parallel; The dc supply input of inverter circuit is in series with positive temperature coefficient thermistor PTC1, constitutes multiple functional protector for abnormal condition.Diode D5 is serially connected between rectification circuit and the power supply filter capacitor, has high power factor, makes the source current wave distortion minimum.Thermistor PTC2 is connected between two negative electrodes of fluorescent tube, realizes the preheating starter.The present invention can be used for compact electronic energy-saving lamp or straight-pipe fluorescent lamp, to improve its reliability and photoelectric technology index.

Description

Have the protector for abnormal condition high power factor electronic lamp

The invention belongs to glow discharge spot lamp, relates to the high power factor electronic lamp that has protector for abnormal condition.

Along with the raising of science and technology development and social demand, people require velocitron that high line power factor is not only arranged, low distortion source current waveform and high-luminous-efficiency; But also must have fluorescent tube open circuit, gas leakage, fracture of wire, do not start and the self-protection function of overvoltage, overcurrent, have high reliability and long working life.In actual use, because the abnormality that power circuit fault and fluorescent lamp performance change are caused is recurrent, the velocitron of developing this class performance and requirement has certain social, economic benefit.

The patent documentation " electric ballast that has abnormal state protection circuit " (notification number CN2086496U) of Xi'an Communications University is disclosed; adopt voltage, current signal sampling; trigger the controllable silicon conducting, the feedback loop of short circuit oscillator forces inverter to quit work and realizes protection.It is equipped with the integral delay circuit of triggering signal electric current in order to prevent false triggering at the SCR control utmost point.Abnormality makes controllable silicon have little time triggering and conducting because of signal code is delayed in case occur, and inversion to enter second breakdown with transistor be that the microsecond level is damaged, and circuit structure complexity.The power rectifier output of this electric ballast is by the direct filtering of large value capacitor, and circuit is capacitive, makes source current be pulse type, and power factor is low to reach 0.55, and the current waveform distortion is serious.

Task of the present invention be to propose a kind of simple in structure, reliable operation, light efficiency high again have a protector for abnormal condition high-power factor electronic electricity-saving lamp.

Task of the present invention is to realize like this, it comprises fluorescent tube, housing and electric ballast, the power input that it is characterized in that electric ballast is through fuse BX varistor MYG in parallel again, by transistor T 1, the dc supply input that T2 and pulse transformer B constitute half bridge inverter circuit is in series with positive temperature coefficient thermistor PTC1, between rectification circuit output end that D1-D4 constitutes and power filter large capacitor C3, be connected to diode D5, its positive pole is connected with the rectification circuit positive output end, negative pole is connected with the anode of C3, a negative electrode of fluorescent tube is connected with the output of inverter circuit through ballast inductance device L6, and another negative electrode is connected with the rectification circuit positive output end through commissure capacitor C6.Be in series with positive temperature coefficient thermistor PTC2 between two negative electrodes of above-mentioned fluorescent tube, said transistor T 1, T2 are that two VMOS pipes constitute, also can replace with two bipolar-type power pipes, said thermistor PTC1 is mounted between two heating panels of T1 and T2.

The present invention's advantage compared with prior art is: according to supply voltage and consumed power that velocitron uses, the capacity of design insurance silk BX and the operating voltage of varistor MYG are carried out overvoltage protection effectively; At the power input series connection positive temperature coefficient thermistor PTC1 of inverter circuit, and be installed between two transistorized heating panels, simply and reliably to the caused overcurrent of working under the abnormality, hotwork self-protection excessively; Be connected to isolating diode between power rectifier circuit output and power supply filter capacitor, the high-frequency current that inverter is exported directly is subjected to the modulation of the pulsating direct current electric current of rectification circuit output, and the line power factor is improved, and the source current wave distortion is minimum; Be in series with thermistor PTC2 between two negative electrodes of fluorescent tube, realize the preheating starter, prolonged fluorescent tube useful life.

Description of drawings:

Fig. 1 is a structural representation of the present invention;

Fig. 2 adopts the electrical schematic diagram of VMOS pipe for the present invention;

Fig. 3 adopts the electrical schematic diagram of bipolar transistor for the present invention;

Fig. 4 is an input voltage waveform of the present invention;

Fig. 5 is a source current waveform of the present invention;

Fig. 6 is a MYG voltage-current characteristic curve;

Fig. 7 is PTC electric current, temperature-resistance characteristic curve.

Now in conjunction with the accompanying drawings the present invention is further described.

With reference to Fig. 1, the present invention is by fluorescent tube 1, and housing 2 and the electric ballast 3 that is contained in the housing are formed.Inwall at fluorescent tube 1 scribbles fluorescent RE powder 4, and making it has higher luminous efficiency than common phosphors.Fluorescent tube 1 is fixedly mounted on above the housing 2, also can make according to the patented technology " inserting type hyperbolic fluorescent lamp " (notification number CN87209826) of our company, and it and electric ballast 3 and housing 2 are separated, and makes inserting type.

Embodiment shown in Figure 2 is the electrical schematic diagram that adopts the VMOS pipe.Fuse BX is connected on the power input of electric ballast, and is connected with the common mode anti-interference filter of L1, L2 composition.Adopt E type magnetic core, two equal turn numbers, direction identical coil L1, L2 on same skeleton, it presents very big induction reactance for the hf interference current that common mode noise and velocitron between power supply phase line and ground wire are taken place, and has good inhibition effect.The capacitor C1 that is in parallel with it strengthens its anti-interference effect.Varistor MYG is connected with two outputs of L1, the L2 of common mode anti-interference filter.Be connected into bridge rectifier by four diode D1-D4,, can connect by the voltage-multiplying type rectification circuit if AC supply voltage is low.Be connected to isolating diode D5 between rectification circuit positive output end and power filter large capacitor C3, its positive pole is connected with the rectification circuit positive output end, and negative pole is connected with the anode of C3.To the positive supply input loop of inverter circuit, be in series with positive temperature coefficient thermistor PTC1 from the anode of capacitor C3, constitute overcurrent, overheated automatic protector.Inverter circuit constitutes semi-bridge type inverter by two VMOS transistor Ts 1, T2 and pulse transformer B.The end of the primary coil L3 of pulse transformer is connected with the output of inverter, and the other end is connected with ballast inductance device L6.Secondary coil L4 is in parallel with grid-source electrode of T1 through R4, and with the L3 homophase; L5 is in parallel with grid-source electrode of T2 through R6, and anti-phase with L3.Voltage stabilizing didoe D7, D8 are in parallel with grid-source electrode of T1, T2 respectively, constitute the positive feedback pulse amplitude limiter.R3 and R5 are connected in the transistorized source electrode loop, play the electric current negative feedback, improve circuit working stability.Diac D6 and resistor R 1, capacitor C4 are connected into trigger starting circuit.The tie point of the positive pole of diode D9 and R1, C4 joins, and negative pole connects the drain electrode of T2, plays clamping action.Because R1 " conducting resistance of T2, after the inverter startup work, the last terminal potential of C4 below the triggering level of D6, is made circuits for triggering withdraw from the triggering state automatically by the D9 strangulation.Phase corrective network R2, C5 series connection back is in parallel with leakage-source electrode of T1, does the phase compensation of high-frequency current.A negative electrode of fluorescent tube 1 is connected with ballast inductance device L6, and another negative electrode directly is connected with the positive output end of rectification circuit behind commissure capacitor C6.After starting capacitor C7 and positive temperature coefficient thermistor PTC2 parallel connection, be connected between two negative electrodes, make to postpone build-up of luminance.

Operation principle of the present invention is: after the energising, civil power is by BX, and by L1, L2 and C2 filtering, filtering also weakens the influence of the high-frequency current of inverter to power circuit from the disturbing pulse of power supply.In case supply voltage surpasses specified allowed band, the varistor MYG at two ends in parallel punctures work, and overvoltage protection is made in the BX quick-break, guarantees the safety of each components and parts of velocitron.By the Rectified alternating current after D1-D4 rectification stream by D5 to the C3 filtering of charging, provide T1, T2 work through PTC1.Pulse transformer B utilizes the positive counter-cyclical of iron core resultant flux to repeat to change and makes transistor take turns conducting output high-frequency current, and igniting through L3, L6 and resonant capacitor C7 makes fluorescent tube 1 work.High-frequency current is directly modulated the Rectified alternating current stream of rectification circuit output through C6 coupling back.Though capacitor C2 is connected in parallel on the rectifier power source output, its capacity is too little, only high-frequency current is constituted path, and greatly anti-to the Rectified alternating current fluid capacitance; Though make the C3 of power filter is big capacity electrolytic capacitor, because the isolation of D5, only bigger at start momentary charge electric current, minimum after the inverter operate as normal from the energy of C3 absorption, thereby the last charging current of C3 is also minimum, make the AC power current waveform basic approaching sinusoidal wave, power factor is improved, and therefore the source current wave distortion also reduces.The high-frequency current that flows to PTC2 in the certain hour of start back makes the thermistor heating with positive temperature coefficient, and after two negative electrodes also were heated simultaneously, its resistance value just jumped to maximum.Because startup capacitor C7 capacity in parallel with it has only the part of C6, so in the series resonant tank of L6, C6, C7, the resonance potential at C7 two ends is several times of C6, high like this electric pulse will excite fluorescent tube 1 to make it starter.Fluorescent tube 1 is lighted between latter two negative electrode voltage and is reduced to operating voltage, and the high-frequency current of the C7 that flows through reduces greatly, and PTC2 keep electric current only below the milliampere level.This soft start operating state has alleviated the black powder phenomenon of sputter that fluorescent tube cold cathode hard excitation causes, tube cathode enters cold conditions work during operate as normal, and this is the key point of prolonging lamp tube working life.The present invention is installed in positive temperature coefficient thermistor PTC1 between two heating panels of T1 and T2, in case occur that fluorescent tube 1 open circuit, gas leakage, negative electrode damage, lamp does not start, the abnormality of starter short circuit or rectifying effect, the operating current that all will cause inverter circuit increases exponentially, the temperature rise of transistor T 1, T2 sharply increases, can be up to 120 ℃ about.Reach operating current or the operating temperature of PTC1, its resistance sharply rises, temperature coefficient can reach+(15-60) %/℃, moment is high-impedance state, realizes overcurrent, overheated automatic protection functions.

According to above-mentioned principle, PTC1 is connected on the drain electrode of T1 drain electrode or T2, and its effect is identical with being connected on the C3 anode with effect in inverter circuit positive supply input loop.

Fig. 3 is the electrical schematic diagram of another embodiment of the present invention, and the structure of its operation principle and L1, L2, MYG, D5, PTC1 and PTC2, effect and last example are basic identical.Difference is that T1, the T2 in the half bridge inverter circuit is made of bipolar transistor, C8 and C9 are connected on respectively in the base loop of T1, T2, R7, R8, D10 and R9, R10, D11 constitute the base bias circuit of T1, T2 respectively, and suitable working point is provided.Diode D12, D13 respectively with T1, T2 reverse parallel connection, constitute the reverse impulse current path, T1, T2 are not breakdown in protection.It was switched on about 0.1 second, automatically be converted to Class C from the Class A operating state, the base stage negative self-bias reaches 0.5-2V, reduce the base storage effect, make transistor T 1, when T2 takes turns to operate, end and turn on delay in advance, the logical drawback of mutual conductance often takes place in the half bridge inverter circuit that significantly reduces the starting of oscillation of common employing diac.

Fig. 4 is an input voltage waveform of the present invention, and Fig. 5 is a source current waveform of the present invention.As can be seen, both phase places are close substantially, and the source current waveform is also near sinusoidal wave.

The major parameter nominal voltage U of the varistor that the present invention is selected.Can be calculated as follows:

$U_o\mathrm{=1.5\; ·}\sqrt{\mathrm{2U}}\mathrm{\pm 10\%}$

U is the AC supply voltage effective value in the formula.

PTC1 and PTC2 should select the saltant positive temperature coefficient thermistor, and its operating current should be complementary with velocitron power, and Curie point should be chosen in before 110 ℃.Fig. 6 is a MYG voltage-current characteristic curve.Fig. 7 is electric current, the temperature-resistance characteristic curve of the PTC element selected for use of the present invention.Wherein the room temperature resistance of PTC1 should be chosen below 10 Ω, and power consumption during with the minimizing operate as normal selects PTC2 should satisfy the preheating requirement of tube cathode, is example with the 20-30W fluorescent lamp, and the cathode preheat electric current is 0.2-0.3A, and be 0.4-2 second warm-up time.D5 should select fast recovery diode, and the trr parameter is preferably less than 1us, and L1, L2 can form with each coiling 150 circle of enamelled wire on the E5 magnetic core.

Through actual measurement, power factor of the present invention can reach more than 98%, and the source current deviation factor of wave can be reduced to 7%, abnormality self-protection reliable in action, and the tube cathode pipeline start up by preheating prolongs about one times of its useful life.The present invention is simple in structure, and debugging is convenient, is applicable to the compact energy-saving velocitron, also can be mounted to the straight-pipe fluorescent lamp of large volume.

Claims (4)

1; have the protector for abnormal condition high power factor electronic lamp; comprise fluorescent tube 1; housing 2 and electric ballast 3; the power input that it is characterized in that electric ballast is through fuse BX varistor MYG in parallel again; by transistor T 1; the dc supply input that T2 and pulse transformer B constitute half bridge inverter circuit is in series with positive temperature coefficient thermistor PTC1; between power rectifier circuit output that D1-D4 constitutes and power filter large capacitor C3, be connected to diode D5; its positive pole is connected with the rectification circuit positive output end; negative pole is connected with the anode of C3; a negative electrode of fluorescent tube is connected with the output of inverter circuit through ballast inductance device L6, and another negative electrode is connected with the rectification circuit positive output end through commissure capacitor C6.

2, the protector for abnormal condition high power factor electronic lamp that has as claimed in claim 1; it is characterized in that being in series with positive temperature coefficient thermistor PTC2 between two negative electrodes of said fluorescent tube 1; said transistor T 1, T2 are that two VMOS pipes constitute; also available two bipolar-type power pipes replace, and said thermistor PTC1 is mounted between two heating panels of T1 and T2.

3, the protector for abnormal condition high power factor electronic lamp that has as claimed in claim 1 or 2; it is characterized in that also being connected to the common mode anti-interference filter that coil L1, L2 constitute between the power rectifier circuit that fuse BX and D1-D4 in the said electric ballast 3 constitute, two coils are same to be connected and on same magnetic core.

4, the protector for abnormal condition high power factor electronic lamp that has as claimed in claim 1 or 2; it is characterized in that said fluorescent tube 1 inwall scribbles fluorescent RE powder 4; it can be fixed in housing 2 with electric ballast 3, also can separate with electric ballast and make inserting type.

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