CN104640260A - Illuminating device using light-emitting diodes of multi-phase alternating current power supply - Google Patents

Abstract

The invention provides a lighting device of a Light Emitting Diode (LED) by using a multi-phase alternating current power supply, which reduces light flicker by using a plurality of alternating voltages with different phases. A multiphase AC to AC power generator generates a plurality of AC voltages of different phases from an AC power source. The AC voltages with different phases are generated by a plurality of rectifiers to generate a plurality of rectified AC voltages, and the rectified AC voltages are used for providing power for a plurality of LED lighting units. The brightness of each led lighting unit varies with the input voltage and reaches the maximum brightness at different times because the phase of the rectified ac voltage connected is different, the variation between the sharp peaks of the overall brightness of the lighting device is reduced, and thus the flickering of the light of the led-based lighting device is also reduced.

Description

Illuminating device using light-emitting diodes of multi-phase alternating current power supply

technical field

The present invention relates to a lighting device based on a light emitting diode (LED), in particular to a driving device and a method for reducing light flicker of a lighting device based on a light emitting diode.

Background technique

Light-emitting diode (LED) is a semiconductor-based light source, which is often used in low-power consumption meters and indicators of home appliances. The application of light-emitting diodes in various lighting devices has become more and more common. For example, high-brightness light-emitting diodes have been widely used in traffic lights, vehicle indicators, and brake lights. In recent years, lighting equipment using strings of high-voltage light-emitting diodes has also been developed to replace traditional incandescent and fluorescent bulbs.

In order to improve the brightness of lighting devices based on LEDs, usually a plurality of LEDs are connected in series to form a lighting unit based on LEDs, and multiple lighting units based on LEDs can be further connected in series to form a lighting unit device. The working voltage required by each lighting device usually depends on the forward voltage of the light-emitting diodes in the lighting unit, how many light-emitting diodes are in each lighting unit, how each lighting unit is connected to each other, and the How the lighting unit receives the voltage from the power supply in the lighting device.

Therefore, in most applications, some type of power voltage conversion device is required to convert the generally more common high voltage power supply to a lower voltage for supplying one or more LED-based lighting units . Because of the need for such a voltage conversion device, the efficiency of the lighting equipment based on the light-emitting diode is reduced, the cost is increased, and it is difficult to reduce its volume.

In order to improve the efficiency and reduce the size of the LED-based lighting device, many technologies have been developed so that the LED-based lighting device can use AC power such as 120V or 240V without a voltage conversion device. Generally, the LEDs in LED-based lighting devices are segmented into a plurality of LED segments. Each LED segment can be selectively turned on and off as the AC voltage increases or decreases under the control of an associated switch or current source. All switches or current sources in the lighting device are controlled by a controller.

FIG. 1 shows a block diagram of a conventional LED-based lighting device powered by an AC voltage source. The AC voltage is rectified by a rectifier 110 to generate a rectified AC voltage. An LED lighting unit 101 receives the rectified AC voltage. The rectified AC voltage is the input voltage.

Such LED-based lighting devices have a simple structure and can also be produced at low cost. However, because the input AC voltage is not stably regulated, the brightness of the LED lighting unit will vary with the input voltage, causing the lighting device based on the LED to flicker strongly. In order to make lighting devices based on light-emitting diodes acceptable in general households to replace traditional incandescent bulbs and fluorescent bulbs, how to reduce light flicker has become an indispensable requirement.

Contents of the invention

The present invention provides an LED-based lighting device with low light flicker. Therefore, the LED-based lighting device of the present invention is powered by a rectified multi-phase AC voltage, thereby reducing the peak-to-peak variation of the brightness of the lighting device. .

In a first embodiment of the present invention, an LED-based lighting device includes an AC power supply, a multi-phase AC-to-AC power generator generating a plurality of different phases of AC voltages for rectifying the plurality of different phases Multiple rectifiers for AC voltage, and multiple LED lighting units. The brightness of each LED lighting unit varies with the input voltage, and the plurality of rectified AC voltages of different phases provide power to the plurality of LED lighting units.

In the second embodiment of the present invention, the LED-based lighting device includes an AC power supply, a multi-phase AC-to-AC power generator generating multiple AC voltages of different phases, and multiple LED AC driving units. The brightness of each LED AC drive unit varies with the input voltage, and the multiple AC voltages with different phases provide power to the multiple LED AC drive units.

In a third embodiment of the present invention, a light-emitting diode-based lighting device includes an AC power supply, a multi-phase AC power generator generating a plurality of different phases of AC-to-AC voltage for rectifying the plurality of different phases multiple rectifiers for the AC voltage, and an LED lighting unit. The brightness of the LED lighting unit varies with the input voltage, and the multiple rectified AC voltages of different phases are connected in parallel to provide power to the LED lighting unit.

Description of drawings

Figure 1 shows a block diagram of a conventional LED-based lighting device powered by an AC voltage power supply;

2 shows a block diagram of an LED-based lighting device including a multi-phase AC-to-AC power generator according to a first embodiment of the present invention;

Fig. 3 shows an example of the LED lighting unit in the first embodiment;

FIG. 4 shows a block diagram of an LED-based lighting device utilizing two AC voltages with different phases according to the first embodiment of the present invention;

FIG. 5A shows voltage values of two-phase AC voltages in the light-emitting diode-based lighting device of FIG. 4;

Fig. 5B shows the voltage value of the rectified two-phase AC voltage;

FIG. 6 shows another example, a block diagram of an LED-based lighting device using three different phases of AC voltages made according to the first embodiment of the present invention;

FIG. 7A shows voltage values of three-phase AC voltages in the light-emitting diode-based lighting device of FIG. 6;

Fig. 7B shows the voltage value of the rectified three-phase AC voltage;

Fig. 8 shows the brightness of the three light-emitting diode lighting units in Fig. 6, along with the three-phase AC voltage variation;

Fig. 9 compares the brightness of an LED lighting unit powered by a single-phase AC voltage, and the brightness of an LED lighting device with three LED lighting units powered by a three-phase AC voltage;

Fig. 10 shows the crest factor of a lighting device based on light emitting diodes powered by single-phase, two-phase and three-phase AC voltages according to the present invention;

11 shows a block diagram of an LED-based lighting device including a multi-phase AC-to-AC power generator according to a second embodiment of the present invention;

FIG. 12 shows a block diagram of an LED-based lighting device using AC voltages of three different phases according to a second embodiment of the present invention;

13 shows a block diagram of an LED-based lighting device including a multi-phase AC-to-AC power generator according to a third embodiment of the present invention;

FIG. 14 shows a block diagram of an LED-based lighting device using AC voltages of three different phases according to a third embodiment of the present invention;

FIG. 15A shows the voltage values of three-phase AC voltages in the LED-based lighting device of FIG. 14;

Figure 15B shows the voltage values of the rectified three-phase AC voltage;

FIG. 16 compares the crest factor of the lighting device based on light emitting diodes according to the first embodiment and the third embodiment in the present invention; and

Figure 17 shows an example where there are N AC voltages of different phases, directly connected to N rectifiers, instead of utilizing multi-phase AC-to-AC power generators to generate AC voltages of different phases.

Wherein, the reference signs are explained as follows:

101, 201, 20N, 401, 402 LED lighting units

110, 211, 21N, 411, 412 rectifier

220 Multi-Phase AC-to-AC Power Generator

341, 342, 34N LED segment

351, 352, 35N Voltage-controlled current limiters with three terminals

371, 37k LED segment

381, 38k Voltage-controlled current limiter with three connections

390 current source

420 Quarter Phase AC-to-AC Power Generator

601, 602, 603 LED Lighting Units

611, 612, 613 rectifier

620 Three Phase AC to AC Power Generator

1101, 110N, 1201, 1202, 1203 LED AC drive unit

1120 Multi-Phase AC-to-AC Power Generator

1220 Three Phase AC to AC Power Generator

1301, 1401, 1701 LED Lighting Units

1311, 131N, 1411, 1412, 1413, 1711, 171N rectifier

1320 Multi-Phase AC-to-AC Power Generator

1420 Three Phase AC to AC Power Generator

Detailed ways

This specification provides accompanying drawings, so that the present invention can be further understood, and the accompanying drawings also constitute a part of this specification. The drawings illustrate the embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 2 shows a block diagram of an LED-based lighting device that utilizes a plurality of AC voltages with different phases to reduce light flicker according to a first embodiment of the present invention. In this embodiment, the device includes a multi-phase AC-to-AC power generator 220, a plurality of rectifiers 211-21N, and a plurality of LED lighting units 201-20N. The multi-phase AC-to-AC power generator 220 generates multiple AC voltages from an AC power source, each AC voltage has a different phase, and the different phases can be evenly or unevenly distributed. Each AC voltage passes through a rectifier to generate a rectified AC voltage for supplying an LED lighting unit.

FIG. 3 shows an example of the LED lighting unit in FIG. 2 . The LED lighting unit comprises a first plurality of LEDs divided into a plurality of LED segments 341-34N, each LED segment having a positive terminal and a negative terminal, respectively connected to a leading LED segment negative terminal and followed by the positive terminal of a LED segment. As shown in Figure 3, the negative terminal of each LED segment is also connected to the first connection terminal of a voltage-controlled current limiter 351-35N comprising three connection terminals, and the second connection terminal of the current limiter A bias voltage V ₁ -V _N is applied, and the third connection end is connected to a common node in the LED lighting unit.

It can also be seen from FIG. 3 that the LED lighting unit further includes a second group of multiple LEDs connected between its common node and the current source 390, and the second group of multiple LEDs is separated into a plurality of light emitting diodes. Diode segments 371-37k. For simplicity of illustration, only one LED is shown for each LED segment, and a plurality of three-connected voltage-controlled current limiters 381-38k are connected in parallel with the plurality of LED segments 371-37k. Each three-terminal voltage-controlled current limiter has a first terminal connected to the positive terminal of a corresponding LED segment, and a second terminal is applied with a bias voltage V _1,x -V _k,x , and the third connection terminal is connected to the first terminal of the current source 390 .

FIG. 4 shows an example made according to the first embodiment of the present invention, wherein a quarter-phase AC-to-AC power generator 420 is used to generate two AC voltages with a phase difference of 90 degrees. The two-phase AC voltage is connected to two rectifiers 411 and 412 respectively, and then the rectified two-phase AC voltage is connected to two LED lighting units 401 and 402 respectively.

FIG. 5A shows the voltage values of the two-phase AC voltage generated from a single-phase 220V AC power source from the device in FIG. 4, and FIG. 5B shows the voltage values of the rectified two-phase 220V AC voltage. As shown in FIG. 4 , in the example of the first embodiment, two LED lighting units 401 and 402 are respectively connected to two rectified AC voltages with a phase difference of 90 degrees.

FIG. 6 shows another example made according to the first embodiment of the present invention, wherein a three-phase AC-to-AC power generator 620 is used to generate a three-phase AC voltage. The three-phase AC voltage is respectively connected to three rectifiers 611, 612 and 613, and then the rectified three-phase AC voltage is respectively connected to three LED lighting units 601, 602 and 603.

FIG. 7A shows the voltage value of the three-phase AC voltage generated by a single-phase 220V AC power supply, and FIG. 7B shows the voltage value of the rectified three-phase 220V AC voltage. As shown in FIG. 6, in the example of the first embodiment, three LED lighting units 601, 602 and 603 are respectively connected to three rectified 220V AC voltages with different phases.

FIG. 8 shows the brightness of three LED lighting units powered by the rectified three-phase AC voltage in FIG. 7B , and the brightness of each LED lighting unit varies with the rectified AC voltage. Because the phases of the three rectified AC voltages are different, the brightness of each LED lighting unit reaches its maximum value at different times. In the present invention, the total brightness of the LED lighting device in the first embodiment is the sum of the brightness of each LED lighting unit, so the variation between peak values of the total brightness is reduced, and the light flicker of the lighting device is also reduced.

9 compares the brightness of an LED lighting unit powered by a single-phase AC voltage with the brightness of the LED lighting device of the first embodiment of the present invention powered by a rectified three-phase AC voltage. It can be seen from Fig. 9 that the peak-to-peak variation of the brightness of the light-emitting diode lighting device powered by the rectified three-phase AC voltage is much lower than that of the light-emitting diode lighting unit powered by the single-phase AC voltage. Obvious small.

The crest factor (crest factor) is often used as an index of light flicker. In order to show the reduction of light flicker, the present invention studies the crest factor in the LED lighting device of the first embodiment. The crest factor is defined as the ratio of the peak value of the light produced by a lighting device to the root mean square value. Figure 10 shows the LED-based lighting powered by rectified single-phase, two-phase and three-phase AC voltages. The crest factor of the device.

It can be seen from FIG. 10 that the crest factor of the LED-based lighting device powered by the rectified two-phase and three-phase AC voltage is obviously lower. The crest factor of LED-based lighting fixtures powered by rectified three-phase AC voltage is very close to that of filament bulbs. The crest factor of LED-based lighting fixtures powered by rectified single-phase AC voltage is higher than that of fluorescent lamps. Figure 10 also shows how the crest factor of an LED lighting unit varies with the number of LED segments.

FIG. 11 shows a block diagram of an LED-based lighting device that utilizes multiple AC voltages of different phases to reduce light flickering according to a second embodiment of the present invention. In the second embodiment, the device includes a multi-phase AC-to-AC power generator 1120, and a plurality of LED AC drive units 1101-110N. The multi-phase AC-to-AC power generator 1120 generates multiple AC voltages from an AC power source, each AC voltage has a different phase, and the different phases can be evenly or unevenly distributed. Each AC voltage is directly connected to a LED AC drive unit whose brightness changes with the input voltage.

FIG. 12 shows an example made according to the second embodiment of the present invention, wherein a three-phase AC-to-AC power generator 1220 is used to generate three-phase AC voltage. The three-phase AC voltage is respectively connected to three LED AC driving units 1201, 1202 and 1203, each LED AC driving unit contains at least one group of LEDs connected in series, and another group of LEDs connected in reverse series. Two groups of light emitting diodes connected in series are connected in parallel with each other.

In order to simplify the description, FIG. 12 shows that each LED AC drive unit only includes two reverse LEDs connected in parallel with each other. It can be seen from FIG. 12 that, for each LED AC drive unit, no matter whether the AC voltage is positive or negative, one LED is turned on.

FIG. 13 shows a block diagram of a lighting device based on LEDs for reducing light flicker by utilizing multiple AC voltages of different phases according to a third embodiment of the present invention. In this third embodiment, the device includes a multi-phase AC-to-AC power generator 1320 , a plurality of rectifiers 1311 - 131N, and an LED lighting unit 1301 . The multi-phase AC-to-AC power generator 1320 generates multiple AC voltages from an AC power source, each AC voltage has a different phase, and the different phases can be evenly or unevenly distributed. Each AC voltage passes through a rectifier to generate a rectified AC voltage, and all rectified AC voltages of different phases are connected in parallel to supply power to the LED lighting unit 1301 .

According to the present invention, the LED lighting unit shown in FIG. 3 can also be applied in the third embodiment. As shown in FIG. 13 , all rectified AC voltages of different phases are connected in parallel and connected to the LED lighting unit 1301 . FIG. 14 shows an example made according to the third embodiment of the present invention, wherein a three-phase AC-to-AC power generator 1420 is used to generate three-phase AC voltage. The three-phase AC voltages are respectively connected to three rectifiers 1411 , 1412 and 1413 , and then the rectified three-phase AC voltages are connected in parallel with each other and connected to the LED lighting unit 1401 .

FIG. 15A shows the three-phase AC power generator 1420 , which generates three-phase AC voltages from a single-phase 220V AC power supply. FIG. 15B shows voltage values of the rectified single-phase 220V AC voltage and voltage values of the rectified three-phase AC voltage applied to the LED lighting unit 1401 . Because there are three rectified 220V AC voltages with different phases connected in parallel to form a rectified three-phase 220V AC voltage, the voltage applied to the LED lighting unit 1401, the individual absolute voltage values of the rectified 220V AC voltages with different phases maximum value. Therefore, the peak-to-peak variation of the voltage value is reduced, so that the light flicker of the LED lighting unit is also reduced.

Fig. 16 shows the crest factor of an LED-based lighting device powered by a rectified three-phase AC voltage according to the first and third embodiments of the present invention, wherein the crest factor depends on the LED in the lighting device The number of segments to display. It can be seen from FIG. 16 that the crest factor of the lighting device of the third embodiment is lower than that of the first embodiment.

It is worth mentioning that, in the above-mentioned embodiments, although a plurality of AC voltages of different phases are exchanged to the AC power generator in a multi-phase, and are generated from a single-phase AC power source, if the If the aforementioned multiple AC voltages with different phases already exist, they can be directly rectified by the rectifier instead of using a multi-phase AC to AC power generator for generation.

For example, in FIG. 17, there are already N different phases of AC voltage, phase-1 to phase-N, directly connected to N rectifiers 1711-171N, instead of utilizing multi-phase AC-to-AC power generators to produce. All the rectified multi-phase AC voltages are connected in parallel with each other and connected to the LED lighting unit 1701 .

Although the present invention is described above only by a few implementation examples, those who are familiar with the technical field can clearly understand that there are still many undescribed modifications and modifications, all without departing from the present invention defined below within the scope of the patent application.

Claims (21)

1. a lighting device utilizing the light-emitting diode of leggy AC power, is characterized in that, comprising:

The alternating voltage of multiple out of phase;

Multiple rectifier, is connected to the alternating voltage of above-mentioned multiple out of phase separately, to produce multiple alternating voltage through rectification; And

Multiple LED lighting unit, is connected to above-mentioned multiple alternating voltage through rectification separately;

Wherein the brightness of each LED lighting unit of above-mentioned multiple LED lighting unit changes along with the voltage of input.

2. lighting device as claimed in claim 1, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is equally distributed.

3. lighting device as claimed in claim 1, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is uneven distribution.

4. lighting device as claimed in claim 1, is characterized in that, comprise again:

One AC power; And

One leggy interchange is connected to above-mentioned AC power, to produce the alternating voltage of above-mentioned multiple out of phase to alternating electromotive force generator.

5. lighting device as claimed in claim 4, it is characterized in that, above-mentioned leggy interchange comprises 1/4th multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator, and the alternating voltage of above-mentioned multiple out of phase comprises the alternating voltage of two phase 90 degree.

6. lighting device as claimed in claim 4, is characterized in that, above-mentioned leggy interchange comprises three multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator.

7. lighting device as claimed in claim 1, it is characterized in that, each LED lighting unit of above-mentioned multiple LED lighting unit comprises:

First group of multiple light-emitting diode is separated into first group of multiple light-emitting diodes pipeline section, and wherein each light-emitting diodes pipeline section has an anode and a negative terminal;

First group of multiple voltage-controlled demand limiter containing three links, wherein each is corresponding with a light-emitting diodes pipeline section in above-mentioned first group of multiple light-emitting diodes pipeline section containing the voltage-controlled demand limiter of three links, and have the first link to be connected to the negative terminal of the light-emitting diodes pipeline section of its correspondence, second link connection is applied in a bias voltage, and the 3rd link is then connected to first common node in this LED lighting unit;

Second group of multiple light-emitting diode is separated into second group of multiple light-emitting diodes pipeline section, wherein each light-emitting diodes pipeline section has an anode and a negative terminal, wherein the anode of first light-emitting diodes pipeline section is connected to above-mentioned first common node, and the negative terminal of last light-emitting diodes pipeline section is connected to second common node in this LED lighting unit;

Second group of multiple voltage-controlled demand limiter containing three links, wherein each is corresponding with a light-emitting diodes pipeline section in above-mentioned second group of multiple light-emitting diodes pipeline section containing the voltage-controlled demand limiter of three links, and have the first link to be connected to the anode of the light-emitting diodes pipeline section of its correspondence, second link connection is applied in a bias voltage, and the 3rd link is then connected to above-mentioned second common node; And

One current source, its first end is connected to above-mentioned second common node, the second end then ground connection.

8. one based on the lighting device of light-emitting diode, it is characterized in that, comprising:

The alternating voltage of multiple out of phase; And

Multiple light-emitting diode alternating voltage driver elements are connected to the alternating voltage of above-mentioned multiple out of phase separately;

Wherein the brightness of each light-emitting diode alternating voltage driver element of above-mentioned multiple light-emitting diode alternating voltage driver element changes along with the voltage of input.

9. lighting device as claimed in claim 8, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is equally distributed.

10. lighting device as claimed in claim 8, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is uneven distribution.

11. lighting devices as claimed in claim 8, is characterized in that, comprise again:

One AC power; And

One leggy interchange is connected to above-mentioned AC power, to produce the alternating voltage of above-mentioned multiple out of phase to alternating electromotive force generator.

12. lighting devices as claimed in claim 11, it is characterized in that, above-mentioned leggy interchange comprises 1/4th multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator, and the alternating voltage of above-mentioned multiple out of phase comprises the alternating voltage of two phase 90 degree.

13. lighting devices as claimed in claim 11, is characterized in that, above-mentioned leggy interchange comprises three multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator.

14. lighting devices as claimed in claim 8, it is characterized in that, it is in parallel mutually that each light-emitting diode alternating voltage driver element of above-mentioned multiple light-emitting diode alternating voltage driver element comprises the reverse light-emitting diode of at least two groups, and wherein each group light-emitting diode comprises the more than one light-emitting diode of or series connection.

15. 1, based on the lighting device of light-emitting diode, is characterized in that, comprising:

The alternating voltage of multiple out of phase;

Multiple rectifier is connected to the alternating voltage of above-mentioned multiple out of phase separately, and to produce multiple alternating voltage through rectification, described multiple alternating voltage through rectification is in parallel mutually; And

A LED lighting unit is connected to above-mentioned multiple alternating voltage through rectification;

Wherein the brightness of above-mentioned LED lighting unit changes along with the voltage of input.

16. lighting devices as claimed in claim 15, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is equally distributed.

17. lighting devices as claimed in claim 15, it is characterized in that, the alternating voltage of described multiple out of phase, its phase place is uneven distribution.

18. lighting devices as claimed in claim 15, is characterized in that, comprise again:

One AC power; And

One leggy interchange is connected to above-mentioned AC power, to produce the alternating voltage of above-mentioned multiple out of phase to alternating electromotive force generator.

19. lighting devices as claimed in claim 18, it is characterized in that, above-mentioned leggy interchange comprises 1/4th multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator, and the alternating voltage of above-mentioned multiple out of phase comprises the alternating voltage of two phase 90 degree.

20. lighting devices as claimed in claim 18, is characterized in that, above-mentioned leggy interchange comprises three multi-phase alternating current to alternating electromotive force generator to alternating electromotive force generator.

21. lighting devices as claimed in claim 15, it is characterized in that, above-mentioned LED lighting unit comprises:

First group of multiple light-emitting diode is separated into first group of multiple light-emitting diodes pipeline section, and wherein each light-emitting diodes pipeline section has an anode and a negative terminal;

First group of multiple voltage-controlled demand limiter containing three links, wherein each is corresponding with a light-emitting diodes pipeline section in above-mentioned first group of multiple light-emitting diodes pipeline section containing the voltage-controlled demand limiter of three links, and have the first link to be connected to the negative terminal of the light-emitting diodes pipeline section of its correspondence, second link connection is applied in a bias voltage, and the 3rd link is then connected to first common node in this LED lighting unit;

Second group of multiple light-emitting diode is separated into second group of multiple light-emitting diodes pipeline section, wherein each light-emitting diodes pipeline section has an anode and a negative terminal, wherein the anode of first light-emitting diodes pipeline section is connected to above-mentioned first common node, and the negative terminal of last light-emitting diodes pipeline section is connected to second common node in this LED lighting unit;

Second group of multiple voltage-controlled demand limiter containing three links, wherein each is corresponding with a light-emitting diodes pipeline section in above-mentioned second group of multiple light-emitting diodes pipeline section containing the voltage-controlled demand limiter of three links, and have the first link to be connected to the anode of the light-emitting diodes pipeline section of its correspondence, second link connection is applied in a bias voltage, and the 3rd link is then connected to above-mentioned second common node; And

One current source, its first end is connected to above-mentioned second common node, the second end then ground connection.