CN202663635U

CN202663635U - Active power factor correcting circuit in electronic ballast of electrodeless lamp

Info

Publication number: CN202663635U
Application number: CN2012203425090U
Authority: CN
Inventors: 张新华; 张若煜
Original assignee: University of Shaoxing
Current assignee: University of Shaoxing
Priority date: 2012-07-16
Filing date: 2012-07-16
Publication date: 2013-01-09
Anticipated expiration: 2022-07-16

Abstract

The utility model discloses an active power factor correcting circuit in an electronic ballast of an electrodeless lamp. The active power factor correcting circuit comprises a chip IR1150, resistors, capacitors and a field-effect tube, wherein a pin GATE of the chip IR1150 is connected with two ends of an output voltage through the field-effect tube. A pin VCC is externally connected with an operating voltage and is grounded through the capacitor. A pin VFB is connected with two ends of the output voltage through partial-pressure serially connected resistors. A pin COMP is grounded through the serially connected resistors and the capacitors. One more capacitor is serially connected at two ends of the serially connected resistors and the capacitors. A pin OVP is connected with two ends of the output voltage through the partial-pressure serially connected resistors. A pin FREQ and a pin ISNS pin are grounded through the resistors. A pin COM is grounded and is connected with the pin ISNS through one capacitor. With the active power factor correcting circuit, current harmonic waves input by the alternating-current mains supply are reduced, and the power factor of a system is improved.

Description

APFC in a kind of electronic ballast of electrodeless lamp

Technical field

The utility model relates to the Non-polarized lamp technical field, and is special relevant with the APFC in a kind of electronic ballast of electrodeless lamp.

Background technology

Non-polarized lamp structurally is comprised of three parts, i.e. radio-frequency generator (high frequency electric source), power coupler and scribble the glass cell-shell of fluorescent RE powder.

Before Non-polarized lamp was not yet lighted, gas was equal to dielectric in the fluorescent tube, and the secondary disconnection of excitation transformer coil, so same pure inductances such as transformer this moments.When inductance flows through high-frequency current, will set up high frequency magnetic field in the inductance core.According to maxwell's Theory of Electromagnetic Field, around the magnetic flux of alternation, will generate the electric field of vortex, this eddy electric field can drive a small amount of free charge in the fluorescent tube.When the intensity of eddy electric field was enough large, free charge meeting that is accelerated was so that the mercury atoms in the fluorescent tube causes the free charge in the fluorescent tube to get more and more.At last, cause avalanche effect, plasma current can be controlled oneself in the fluorescent tube, and in the mercury ion ionization process, can produce ultra-violet radiation, like this with regard to the fluorescent material on the exciter lamp tube wall, sends visible light, and lamp will be lit.

After Non-polarized lamp was lit, the conductivity of gas increased in the electrodeless lamp tube, and excitation transformer is by the elementary secondary transferring energy of fluorescent tube of giving.The electric charge of high-frequency alternating magnetic field in the excitation transformer in the alternation eddy electric field continuation driving fluorescent tube of discharge tube internal induction, the fluorescent tube plasma current is increasing, the mercury ion of ionization is also more and more, is limited in certain scope by the resonant inductance in the electric ballast at last.Electric energy in the ballast is passed in the electrodeless lamp tube endlessly by excitation transformer, and Non-polarized lamp sends lasting visible light.

This shows that electron rectifier opens great role in the Non-polarized lamp course of work, generally comprise rectification unit, APFC, half-bridge inversion circuit.Existing APFC calibration result is unstable, the easily final work that starts Non-polarized lamp of impact, the inventor has done research for the Non-polarized lamp commutation technique, designs a kind of APFC of electronic ballast of electrodeless lamp, and this case produces thus.

The utility model content

Main purpose of the present utility model provides the APFC in a kind of electronic ballast of electrodeless lamp, reduces the current harmonics of electric main input, improves the power factor of system.

In order to achieve the above object, the utility model is achieved through the following technical solutions:

APFC in a kind of electronic ballast of electrodeless lamp comprises chip I R1150, some resistance, some electric capacity, field effect transistor; Wherein the GATE pin of chip I R1150 connects the output voltage two ends by field effect transistor; The external operating voltage of VCC pin of chip I R1150, and pass through capacity earth; The VFB pin of chip I R1150 is connected to the output voltage two ends by the dividing potential drop series resistance; The COMP pin of chip I R1150 is by series resistance and capacity earth, and at the resistance of series connection and electric capacity two ends an electric capacity in parallel again; The OVP pin of chip I R1150 is connected to the output voltage two ends by the dividing potential drop series resistance; FREQ pin and the ISNS pin of chip I R1150 pass through respectively grounding through resistance; The COM pin ground connection of chip I R1150, and be connected with the ISNS pin by electric capacity.

After adopting such scheme, current loop utilizes embedded input voltage signal to control average current input, allows it follow input voltage and changes.The external voltage loop is being controlled the output voltage of boost converter, realizes the adjusting of power factor correction and output voltage.

Description of drawings

Fig. 1 is the circuit diagram of the utility model preferred embodiment.

Embodiment

By reference to the accompanying drawings, preferred embodiment is described in further details to the utility model.

APFC in a kind of electronic ballast of electrodeless lamp, as shown in Figure 1, four bridge circuits that diode forms, its input connects electric main ACinput, and output forms 385Voutput, and alternating current is carried out rectification.

The utility model adopts " monocycle control " control technology, mainly includes chip I R1150, some resistance, some electric capacity, field effect transistor.Wherein the GATE pin of chip I R1150 connects the output voltage two ends by field effect transistor Q1.The external operating voltage vcc of VCC pin of chip I R1150, and by capacitor C 5 ground connection.The VFB pin of chip I R1150 is connected to the output voltage two ends by dividing potential drop series resistance R5, R6, R7.The COMP pin of chip I R1150 is by series resistance R4 and capacitor C 3 ground connection, and at the resistance R 4 of series connection and capacitor C 3 two ends a capacitor C 4 in parallel again.The OVP pin of chip I R1150 is connected to the output voltage two ends by dividing potential drop series resistance R8, R9, R10.The FREQ pin of chip I R1150 and ISNS pin are respectively by resistance R 1, R3 ground connection.The COM pin ground connection of chip I R1150, and be connected with the ISNS pin by capacitor C 2.

APFC 2 current loops utilize embedded input voltage signal to control average current input, allow it follow input voltage and change.The external voltage loop is being controlled the output voltage of boost converter, realizes the adjusting of power factor correction and output voltage.The design process of physical circuit is:

1, inductor design

Power taking sensor current pulsation coefficient

Figure 2012203425090100002DEST_PATH_IMAGE004

=30, calculate through formula (1)

=1.45mH adopts PQ35/35 PCAO magnetic core and 0.Olmm

100 multi cords are got

Figure 2012203425090100002DEST_PATH_IMAGE012

2OO μ H, close around 85T.

2, input capacitance design

Figure 2012203425090100002DEST_PATH_IMAGE014

Maximum voltage ripple factor during high frequency (

), exemplary value is got r=6% in the design between 3% to 9%, calculated as can be known by formula (2), and the high frequency input capacitance is nominal value C=

, model is CBB21 film high frequency capacitance.

3, output capacitance design

Allow the output voltage ripple fluctuation in ± 3.5%, known that by formula (3) output filter capacitor choice criteria numerical value is C6=

4, metal-oxide-semiconductor and fly-wheel diode

When MOSFET turn-offs, the anti-phase withstand voltage 400V that it bears, then

400V, when defeated people's voltage is minimum,

=2.44A.Selecting metal-oxide-semiconductor is the FQP11N50CF of fairchild company.Rectifier diode is when turn-offing, and the inverse peak voltage that bears is 400V, then VR〉400V, the electric current that flows through rectifying tube is

=0.57A, the fast recovery diode MUR360 of selection ON company.

5, control circuit design

The output voltage of transducer be by

,

With

The voltage divider that forms is set, and gets =

=499k Ω, tolerance is 1%.Reference voltage Vf=7.0V then uses nominal value resistance

=18.5k Ω/0.25W.

The factor of synthetic circuit electromagnetic interference performance, optimum inductor and power switch loss several respects, the selector switch frequency is

100kHz, at this moment R3=90k Ω.

Detect the resistance of electric current Should be minimum at input voltage, power output is for designing peak inrush current and load overload factor when power taking inducing current derate is used in the maximum situation

=5%, then:

Calculate

=0.55 Ω, power taking resistance nominal value =0.47 Ω, power are 2W.

In the system of peak current control, need to use external filter, now design the RC filter, its corner frequency design, is selected for the RC filter at about 1～1.5MHz

100 Ω,

The rated voltage of output capacitor is 450V, prevents that output voltage from exceeding the maximum rated voltage of output capacitor, and design output over-voltage protection (OVP) voltage divider is: =

=499k Ω;

=17.9k Ω.

Above-described embodiment only is used for explaining inventive concept of the present utility model, but not to the restriction of the utility model rights protection, allly utilizes this design that the utility model is carried out the change of unsubstantiality, all should fall into protection range of the present utility model.

Claims

1. the APFC in the electronic ballast of electrodeless lamp is characterized in that: comprise chip I R1150, some resistance, some electric capacity, field effect transistor; Wherein the GATE pin of chip I R1150 connects the output voltage two ends by field effect transistor; The external operating voltage of VCC pin of chip I R1150, and pass through capacity earth; The VFB pin of chip I R1150 is connected to the output voltage two ends by the dividing potential drop series resistance; The COMP pin of chip I R1150 is by series resistance and capacity earth, and at the resistance of series connection and electric capacity two ends an electric capacity in parallel again; The OVP pin of chip I R1150 is connected to the output voltage two ends by the dividing potential drop series resistance; FREQ pin and the ISNS pin of chip I R1150 pass through respectively grounding through resistance; The COM pin ground connection of chip I R1150, and be connected with the ISNS pin by electric capacity.