CN2195839Y - Electronic ballast - Google Patents

Abstract

The utility model relates to an electronic ballast, which is composed of a power part, a rectification part, a filtering part, a switching control part and a lamp output part. The power factor of the utility model can be reached as high as 95%, and the energy saving effect is remarkable. The harmonic interference is small, the effect to the electric network and the household electrical appliances is small, and the lamp current peak factor is small. Due to the ballast and the lamp tube are all work under the low temperature, the lifetime of the ballast can be reached 25 years, and the lifetime of the lamp tube can be increased about one time. The utility model has the advantages of small size and light weight, the lamp tube can be started in a moment, and the utility model can work in a low voltage area and an unstable area as usual.

Description

Electronic ballast

The utility model belongs to a kind of electric ballast.

Existing ballast comprises traditional type ballast and electronic ballast.The traditional type ballast is the inductance of being made by silicon steel sheet, cooperates a starter to be composed in series.Its shortcoming is that weight is big, and volume is big, is not suitable for new-type light fixture; Power factor too low (about about 50%) is so power consumption is big; Electric current is too big, so the temperature of ballast and fluorescent tube is higher, both life-spans are all short; Fluorescent lamp glimmers significantly, during power supply 50Hz fluorescent lamp in fact each second switch 100 times, so flicker 100 times diminishes eyesight; Harmonic Interference (leakage) is big, influences power supply grid and household electrical appliance; Area in power shortage often can not start fluorescent lamp.At present commercially available electric ballast is an electronic switch in fact just; the unprotect loop; and regulation voltage and electric current automatically; power factor is too low; about 50-60%; harmonic distortion surpasses 100%, and energy-saving effect is not remarkable, can not reach the energy conservation standard (countries in the world are the clearest and the most definite with U.S.'s specification at present) of USDOE's regulation fully.That is:

Power factor is greater than 95%

Harmonic Interference is less than 25%

The lamp current peak factor is below 1.7%

The purpose of this utility model is at the deficiencies in the prior art part, provides the high energy-saving effect of a kind of power factor remarkable, and Harmonic Interference is little, and little to electrical network and household electrical appliances influence, the lamp current peak factor is little, and light is stable, and temperature rise is low, safing electric ballast.

The utility model is made up of power unit, rectifying part, filtering part, conversion and control part and lamp output, series connection negative tempperature coefficient thermistor L1 on power unit fuse F1; The filtering part is made up of capacitor C 3, C4 and diode D5, D6, D7 and resistance R 1, R2, R3, wherein capacitor C 4 is in parallel with resistance R 3, capacitor C 3 is in parallel with resistance R 2, capacitor C 4 is connected with capacitor C 3 via diode D7, resistance R 1, capacitor C 4 is connected with diode D6, and capacitor C 3 is connected with diode D5.

The utility model adopts integrated circuit and accurate electronic component, its operating frequency between 30K to 50KHz, so do not glimmer, harmless to human eye.It can increase the light output (LUMEN) of fluorescent lamp, so same fluorescent tube during with high-frequency electronic the brightness with 50Hz can increase 8-10%: the high-frequency current of its supply fluorescent tube has only about the 1/4-1/3 of traditional ballast supplying electric current, so power factor is high, reach more than 95%, 35-50% therefore can economize on electricity.Its low current is all worked ballast and fluorescent tube at low temperatures, thus the life-span of ballast can reach 25 years, and about the life-span of fluorescent tube can double.Its volume is little, and is in light weight, can moment start fluorescent tube, and in undertension and the work as usual of unsettled area.

The more commercially available electronic ballast power factor of the utility model improves more than 0.35, and Harmonic Interference is less than 25%, and the lamp current peak factor is about 1.7; Temperature rise has only the 10-15 degree.The performance of the utility model and commercially available electric ballast relatively sees the following form:

Electric ballast performance comparison sheet

The item compared brand	Power output (W)	Input power (W)	Power factor	The current peak factor	Current harmonics (%)
						Li Keming 40Y-40E white clouds YS-91 Beijing 701 the utility model	32.72 38.19 40.81 41.04	58.33 67.09 60.27 42.59	0.580 0.589 0.677 0.964	3.966 3.720 2.450 1.718	126.04 122.00 34.91 23.91

Above result measures under the situation of equivalent environment identical device: input voltage 230V, load 40W.

Fig. 1 is the utility model functional-block diagram.

Fig. 2 is a circuit diagram of the present utility model.

Below in conjunction with accompanying drawing the utility model is described in detail.

The utility model is made up of power unit 1, rectifying part 2, filtering part 3, conversion and control part 4 and lamp output 5.

Power unit is made up of C1, F1 and L1, but wherein the C1 filtering by the noise of alternating current circuit.F1 is a fuse, if the improper or component wear of assembling is arranged, when causing overload condition, circuit can be disconnected in circuit, does not influence power supply network, avoids causing danger.L1 is a negative tempperature coefficient thermistor, but causes through the effect of the resistance thus peakedness ratio with electric current.Fuse F1 connects with negative tempperature coefficient thermistor L1

Rectifying part is made up of D1, D2, D3, D4, is a bridge rectifier.

Pulsating direct current through gained behind the bridge rectifier is added on the filter circuit.Filtering part, general ballast are that rectification connects an electrochemical capacitor afterwards, or two capacitances in series constitute.By the operation principle of rectification circuit as can be known, capacitance not simultaneously, the waveform of filtering voltage is also different.And the ON time of rectifier diode is also different.Capacitance is more little, and the ON time of diode is long more.Only use capacitor filtering, the alternating electron ballast is had bigger influence, and also can cause bad influence to the life-span of gaseous discharge lamp.We are brought in by the input of alternating electron ballast and see, because wave distortion causes the system power factor low, and harmonic content is big in the input current, wherein based on triple-frequency harmonics, at a large amount of alternating electron ballasts that use, when adopting the three-phase and four-line power supply, on center line, form the neutral current that equals 1-1.5 times of left and right sides line current.This neutral current is that electrical network is caused quite big harm with triple harmonic current.Filter circuit directly can have influence on the operating current waveform of system power factor, current harmonics and lamp.

Filtering part of the present utility model is made up of capacitor C 3, C4 and diode D5, D6, D7 and resistance R 1, R2, R3, wherein capacitor C 4 is in parallel with resistance R 3, capacitor C 3 is in parallel with resistance R 2, capacitor C 4 is connected with capacitor C 3 via diode D7, resistance R 1, capacitor C 4 is connected with diode D6, and capacitor C 3 is connected with diode D5.When we with per half period in the ON time of rectifier diode when increasing, the electric current of conducting is similar to the voltage waveform in this period as much as possible, promptly near sinusoidal wave.Then conducting is long more, and the harmonic wave in the input current is fewer.And power factor also improves relatively.This filter circuit changes rectification circuit to filter capacitor charging and discharge time constant with diode, and the method for discharge voltage, reaches and improves Harmonics of Input, improves the purpose of system power factor.C4 is through diode D7 when charging, and R1 connects with C3, and when two capacitances were identical, each electric capacity was chargeable to the Um/2 value.Be parallel to the last resistance R of C3, C4 2, R3 is a balance resistance, but the voltage of balance two capacitors.During discharge, capacitor C 3, C4 are by diode D5, D6 parallel discharge.In phase, commutating voltage is opened diode D5, D6 in the time of during 30 degree-90 degree, the D7 conducting weekly.Capacitor C 3, C4 series connection, each electric capacity is charged to Um/2, and commutating voltage is powered to converter simultaneously.During 90 degree-150 degree, commutating voltage descends according to sinusoidal rule.At this moment, capacitor C 3, C4 do not charge and also do not discharge, this period commutating voltage still power to converter.More than supply with converter during two electric current and commutating voltage be directly proportional.During the 150-210 degree, commutating voltage is lower than the voltage of each capacitor, and under the effect of C4, C3, diode D7 closes, and D5, D6 open, and C4, C3 parallel connection are powered to converter.We can make capacitor discharge voltage be not less than about 150V in this period as long as select suitable C1+C2 value, and this moment, commutating voltage was lower than condenser voltage, no longer powered to converter.The ON time of rectifier diode is corresponding to the power-on time of converter with rectification circuit.Via mode like this, and improve power factor, reach energy-saving effect.Harmonic Interference is also little simultaneously, and is also little to electrical network and household electrical appliances influence.The lamp current peak factor is little, and light is stable, has prolonged the life-span of fluorescent tube.

Conversion portion forms square wave with the AC line voltage of input circuit under certain frequency, and the square wave of conversion is outputed to the LC resonant circuit that comprises lamp.

Control section is the auto-excitation type mode of oscillation.Comprise diac and driver transformer.In this part, used a thick film IC (AT-200), voltage stabilizing is provided and has triggered function, the reliability of circuit is improved.AT-200IC is a trigger control circuit, and R8 is to power positive end for the series connection of AT-200IC the 1st pin, and R8 is an adjustment resistance, when trigger voltage reaches the set point of IC inside, send one via IC the 2nd pin and control signal to the T2 base stage, make the T2 conducting, T1, T2 are an electronic switch.IC the 3rd pin is connected to the T2 collection utmost point, and the 4th, 5 pin are empty pin, and the 6th pin is held with being connected to.After system enters operate as normal, T1 and T2 are directly by L3 control, and we can recently control the magnitude of current of input transistors base stage by the number of turn that changes L3, and D9 and R5 also are attached to the T1 base stage, D8 and R4 also are attached to the T2 base stage, the size of the set point controlled amount system base current of this R4 and R5.The directivity of D8, D9 may command input T1, T2 base current.The T1 collection utmost point, emitter-base bandgap grading D11 in parallel, D10 in parallel between the T2 collection utmost point, emitter-base bandgap grading.As T1, the T2 collection utmost point, when the emitter-base bandgap grading revers voltage is too high, D11, D10 have played protective effect, make that T1, T2 are unlikely to be burnt.T1 emitter-base bandgap grading series connection R6, R7 is to ground for the series connection of T2 emitter-base bandgap grading.The controlled amount system of this R6, R7 resistance flows through the size of T1, the T2 collection utmost point, emitter current, the also size of may command power output.

The lamp output: the resonance phenomena that inductance and electric capacity produced that the conversion portion utilization is connected with lamp converts the sine wave of supply voltage to square wave, and sends lamp to.The frequency of system is determined by the selected frequency of LC resonant circuit, and then the frequency of determining by this way feeds back to transducer as resonance frequency by control circuit again.The LC resonant circuit is at initial open-circuit condition, obtains the desired about 800V(PP of arc discharge) high voltage.

Fluorescent tube if operating frequency greater than 15KHz when above because conversion rate is too fast, the charge and discharge phenomena of fluorescent lamp inside has had little time reflection.So electronic ballast does not have stroboscopic phenomenon.And the operating frequency of this circuit is 30-50KHz.

Claims (1)

1, a kind of electric ballast is made up of power unit, rectifying part, filtering part, conversion and control part and lamp output, it is characterized in that power unit fuse F1 goes up series connection negative tempperature coefficient thermistor L1; The filtering part is made up of capacitor C 3, C4 and diode D5, D6, D7 and resistance R 1, R2, R3, wherein capacitor C 4 is in parallel with resistance R 3, capacitor C 3 is in parallel with resistance R 2, capacitor C 4 is connected with capacitor C 3 via diode D7, resistance R 1, capacitor C 4 is connected with diode D6, and capacitor C 3 is connected with diode D5.

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