CN1187748A - Electronic ballast for high-intensity discharge lamps - Google Patents
Electronic ballast for high-intensity discharge lamps Download PDFInfo
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- CN1187748A CN1187748A CN97121243A CN97121243A CN1187748A CN 1187748 A CN1187748 A CN 1187748A CN 97121243 A CN97121243 A CN 97121243A CN 97121243 A CN97121243 A CN 97121243A CN 1187748 A CN1187748 A CN 1187748A
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Abstract
An electronic ballast comprises an inverter section (17, 19) to supply a load (L) at high frequency, control means (43) which generate a switching signal for the said inverter section, and means of modulating the frequency of the said switching signals. The switching signal is modulated by the modulating means with a modulating signal having a triangular waveform.
Description
The present invention relates to a kind of power supply or ballast and be used for high frequency, particularly but be not only to be used for high-intensity discharge (HID) lamp to an electric.
Have tens KHz magnitudes, generally about 20KHz, the ballast of frequency is used for high-intensity lamp, for example the power supply of metal halide lamp.One of subject matter that runs in the power supply of this class lamp results from such fact, and supply frequency triggers resonance phenomena in lamp, causes the life-span of lamp to be reduced.
Resonance frequency changes in quite wide scope from lamp to a lamp, therefore can not design ballast like this, makes supply frequency automatically get rid of the resonance frequency of lamp.
Various systems in the effort that addresses the above problem, have been designed.Especially, proposed and power to lamp with variable frequency rather than with constant frequency, to prevent to trigger resonance phenomena.In people such as LaszloLaskai " the white noise modulation of high frequency high intensity discharge lamp ballast ", P.1953 1/1994 IEEE among the ff., has stated the mathematical analysis of this solution.Analysis and research for the mathematics aspect should in this piece article, propose and power to lamp with the frequency or the phase place of change at random with reference to this piece article.This just need add a quite complicated and expensive electronic circuit on the pwm circuit that produces switching signal to.
The objective of the invention is to, provide a kind of circuit of much simple and more cheap different structure, with the similar problem that solves the resonance problems in the HID lamp or in load, exist by the high frequency ballast power supply.
According to the present invention, change the frequency of switching signal in time by means of modulation signal with triangular waveform, the frequency of the frequency ratio switching signal of these triangular waveforms is much lower, low approximately two orders of magnitude.With regard to circuit structure, the solution that proposes according to the present invention is compared with the required circuit of randomly changing frequency that is used for of current use, produces a kind of simple especially circuit solution.
In practice, the detailed description of the invention a kind of electric ballast, this ballast comprises: a phase inverter part powers to the load with high frequency; Control device is for described phase inverter partly produces a switching signal; And the device of the described switching signal frequency of modulation.On feature, switching signal is by the modulating device modulation with triangular waveform modulation signal.
In the embodiment of a reality, modulating device comprises a triangular current generator, and the output of this generator is connected on the plate of a capacitor, and the charging rate of capacitor has been determined the frequency of switching signal.
On feature, inversion frequency can have the magnitude of 10-30kHz, and the frequency of modulation signal can have the magnitude of 80-150Hz.Have the 110-120Hz magnitude for the good especially value of modulation signal, and 115-120Hz preferably.
In a possible embodiment, modulating device comprises that is connected to the timer on the operational amplifier, this transistorized disconnection of amplifier control and connection.
To be expressly understood more that by description and accompanying drawing the present invention, accompanying drawing represent a non-limiting example of the present invention.In the accompanying drawings,
Fig. 1 represents to implement a circuit diagram of the present invention;
Fig. 2 represents that modulation signal over time;
Fig. 3 is illustrated in the voltage as the function of time on the CT plug of pwm circuit;
Fig. 4 represents the variation of electric current in frequency domain of lamp; And
Electric current is as the variation of the function of time in Fig. 5 indication lamp.
The top of circuit diagram is the reduced graph of ballast 1 that is used for the power supply of HID type lamp 2 in Fig. 1.
Switch 17 and 19 disconnection and connect by inductor 33,35 controls that are wrapped on the public iron core 37 are being twined the inductor 39,41 that is connected on transistor 17,19 base stages on the public iron core 27 altogether, and transistor 17,19 forms the controlled switch of phase inverters.
Make switch 17,19 alternately conducting and disconnection, so that power to lamp L with the voltage that changes according to following rule:
V (t)=Vsin (w
oT+ φ (t)) (1) wherein t be the time, w
oBe the fundamental frequency of carrier signal, and φ (t) is a modulation signal, its time derivative has leg-of-mutton variation, as shown in Figure 2, the frequency of 80-150Hz magnitude is for example arranged, and better is the magnitude of 100-130Hz, and optimum value approximately is 115-118Hz.A kind of possible circuit solution is represented in the bottom of figure among Fig. 1, is used for the switching signal frequency modulation(FM) to switch 17,19, and the modulation signal with the triangular waveform of type shown in Fig. 2 is provided.Pwm circuit of label 43 expression, the integrated circuit of model UC2525A or equivalence for example, 16 plugs of this circuit are represented with the corresponding standard title.Output plug OUTA and OUTB provide the signal of opposite phase to switch 17,19, with the control phase inverter.Depend on the element that is connected on RT and the CT plug in the signal frequency on OUTA and the OUTB (so inversion frequency of phase inverter).The RT plug is through resistor 45 ground connection, and the CT plug is connected on the capacitor 47 and through a resistor 49 and receives on the discharge plug DISC.Under normal operating condition, by 47 chargings of a current i, the result has increased the voltage on the CT end to capacitor 47 gradually.The internal structure of circuit 43 is such, and when the voltage on the CT end reached a predetermined value, capacitor 47 discharged into the DISC end rapidly through resistor 49.
When not having other circuit elements to be connected on CT and the RT end, the zigzag that the voltage on CT has type shown in Figure 3 changes, but the constant frequency with carrier signal on OUTA and OUTB end.
In order to obtain frequency modulation(FM), the positive plate of capacitor 47 is connected to through a diode 51 does on the as a whole triangular current generator by label 53 expressions.Do not describe the structure of generator 53 in detail, because it can be made in the mode that those skilled in the art is familiar with.In general, it can comprise: a timer 55, for example an IC555 type integrated circuit; An operational amplifier 57 is connected on this timer; And a transistor 59, make its base stage be connected to the output of operational amplifier 57, its emitter is connected to the end of convert of amplifier 57, and its collector electrode is connected on the diode 51.
By this way, in capacitor 47 charge cycles, reach the voltage that causes through the discharge of DISC end, this charge cycle time to time change, this changes corresponding to the output current from circuit 53 and changes.Therefore, corresponding to the non-constant frequency at OUTA and OUTB end upconverted signal, the zigzag that the voltage at capacitor 47 two ends has non-constant frequency changes.
Fig. 3 is illustrated in the voltage V on the CT end
CTQualitative variation in time.In order to represent to use from the resulting frequency modulation(FM) effect of the electric current of circuit 53, the interval of the half period by approximating the triangular wave that circuit 53 produces is at time interval T
1And T
2In two parts voltage signal be separated from each other, and be illustrated on the same time diagram among Fig. 3.Voltage signal frequency on the CT end is higher than interval T
1, in interval T
1In current value from circuit 53 bigger.Different therewith, V
CTFrequency at time interval T
2In lower, at time interval T
2The charging of middle capacitor 47 is slower, because less from the electric current of circuit 53.Voltage signal V
CTEach cycle P, P ' corresponding to a circulation of PWM generator, PWM generator on OUTA and OUTB output thereby will comprise modulation signal with variation shown in Figure 2.
Because switch 17,19 results by means of the conversion of signals on OUTA and OUTB, the change list in its frequency domain is shown in the electric current I among Fig. 4
LTo flow to lamp L.For the modulation band width of 5kHz, under the modulating frequency of 116Hz, obtain the figure among Fig. 4.As seeing among Fig. 4, as supposition w
o(seeing formula (1)) when having the value of 22.5kHz, its frequency spectrum designation 20 and 25kHz between window in actual energy spectral density uniformly.
Fig. 5 represents the apparent instantaneous frequency for 20.49kHz, changes as the electric current of the lamp of the function of time.
Should be appreciated that accompanying drawing only has been provided by an example that provides, only as a kind of practical illustration of the present invention, and the present invention can and arrange change in its form, and do not depart from the scope of the present invention and instruct notion.Any label in claims has the purpose of being convenient to reference to specification and accompanying drawing reading right claim, does not limit the protection range that claims are represented.
Claims (5)
1. electric ballast, comprise: one with the phase inverter part (17,19) of high frequency to load (L) power supply, partly produce the control device (43) of a switching signal for described phase inverter, and the device of the described switching signal frequency of modulation, it is characterized in that switching signal is by the described modulating device modulation with triangular waveform modulation signal.
2. ballast according to claim 1, it is characterized in that, described modulating device comprises a triangular current generator (53), and the output of this generator is connected on the plate of a capacitor (47), is determined the frequency of switching signal by the charging rate of capacitor (47).
3. ballast according to claim 1 and 2 is characterized in that inversion frequency has the magnitude of 10-30kHz, and the frequency of modulation signal has the magnitude of 80-150Hz.
4. ballast according to claim 3 is characterized in that, modulation signal frequency have the magnitude of 110-120Hz, and preferably about 115-120Hz.
5. according to one or more described ballasts in the above claim, it is characterized in that described modulating device comprises a timer (55) that is connected on the operational amplifier (57), the disconnection and the connection of this amplifier transistor of control (59).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97121243A CN1187748A (en) | 1996-10-31 | 1997-10-30 | Electronic ballast for high-intensity discharge lamps |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP96830557.3 | 1996-10-31 | ||
| CN97121243A CN1187748A (en) | 1996-10-31 | 1997-10-30 | Electronic ballast for high-intensity discharge lamps |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1187748A true CN1187748A (en) | 1998-07-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN97121243A Pending CN1187748A (en) | 1996-10-31 | 1997-10-30 | Electronic ballast for high-intensity discharge lamps |
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| Country | Link |
|---|---|
| CN (1) | CN1187748A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102918931A (en) * | 2009-12-10 | 2013-02-06 | 偶氮数字化公司 | Method for controlling high intensity discharge lamp and supply system for high intensity discharge lamp |
-
1997
- 1997-10-30 CN CN97121243A patent/CN1187748A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102918931A (en) * | 2009-12-10 | 2013-02-06 | 偶氮数字化公司 | Method for controlling high intensity discharge lamp and supply system for high intensity discharge lamp |
| CN102918931B (en) * | 2009-12-10 | 2015-08-12 | 偶氮数字化公司 | For the electric power system of the method and high-intensity gas discharge lamp that control high-intensity gas discharge lamp |
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| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |