TW201519692A - An LED-based lighting apparatus powered by multi-phase AC voltages - Google Patents

Abstract

An LED-based lighting apparatus is powered by multi-phase AC voltages to reduce flicker. A multi-phase AC-to-AC power generator is used to generate a plurality of AC voltages from an AC power source. The plurality of AC voltages each having a different phase are rectified by a plurality of rectifiers to provide a plurality of rectified AC voltages for a plurality of LED lighting units. Each LED lighting unit has voltage dependent brightness and reaches maximum brightness at different time due to the phase difference in the rectified AC voltage. The peak-to-peak variation in the total brightness is reduced and therefore the LED-based lighting apparatus has low flicker.

Description

Light-emitting diode lighting device using multi-phase AC power source

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

Light-emitting diodes (LEDs) are semiconductor-based light sources that are often used in low-power meters and appliances, and the use of light-emitting diodes has become more common in a variety of lighting devices. For example, high-brightness LEDs have been widely used in traffic lights, vehicle lights, and brake lights. In recent years, lighting devices using high voltage LED strings have also been developed to replace conventional incandescent bulbs and fluorescent bulbs.

In order to improve the brightness of the illumination device based on the light-emitting diode, a plurality of light-emitting diodes are usually connected in series to form a lighting unit based on the light-emitting diode, and a plurality of lighting units based on the light-emitting diode can be further Further connected in series to form a lighting device. The working voltage required for each illuminating device is usually determined by the forward voltage of the illuminating diode in the lighting unit, and how many illuminating diodes are in each lighting unit, how each lighting unit is connected to each other. And how each lighting unit receives the voltage from the power source in the lighting fixture.

Therefore, in large and complex applications, some type of power supply voltage conversion device is required to convert a generally common high voltage power supply into a lower voltage to provide a Or a plurality of lighting units based on light emitting diodes. Since such a voltage conversion device is required, the efficiency of the illumination device based on the light-emitting diode is reduced, the cost is increased, and it is difficult to reduce the volume.

In order to improve the efficiency and reduce the volume of a light-emitting diode-based lighting device, many technologies have been developed to enable a light-emitting diode-based lighting device to use a voltage conversion device such as 120V or 240V. AC power. Generally, a light-emitting diode in a lighting device based on a light-emitting diode is divided into a plurality of light-emitting diode segments. Each of the light-emitting diode segments 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 of the switches or current sources in the luminaire are controlled by a controller.

1 shows a block diagram of a conventional LED-based illumination device powered by an AC voltage source, the AC voltage being rectified by a rectifier 110 to produce a rectified AC voltage, a LED illumination unit. 101 receives the rectified AC voltage as an input voltage.

Such a lighting device based on a light-emitting diode has a simple structure and can also be produced at a low price. However, since the input AC voltage is not stably adjusted, the brightness of the illumination unit of the LED is changed as the input voltage changes, so that the illumination device based on the LED has a strong light flicker. In order to replace the traditional incandescent bulbs and fluorescent bulbs with lighting devices based on LEDs, it has become an indispensable requirement for reducing the flashing of lights.

The invention provides a low-light flashing illumination device based on a light-emitting diode Therefore, the illuminating device based on the illuminating diode of the present invention supplies electric power from the rectified multi-phase AC voltage, thereby reducing variations in the peak value of the brightness of the illuminating device.

In a first embodiment of the present invention, an illumination device based on a light-emitting diode includes an AC power source, a multi-phase AC to AC power generator that generates a plurality of AC voltages of different phases, for rectifying the plurality of different phases A plurality of rectifiers of alternating voltage, and a plurality of light emitting diode lighting units. The brightness of each of the light-emitting diode illumination units varies with an input voltage, and the plurality of rectified AC voltages of different phases provide power to the plurality of light-emitting diode illumination units.

In a second embodiment of the present invention, an illumination device based on a light-emitting diode includes an AC power source, a multi-phase AC to AC power generator that generates a plurality of AC voltages of different phases, and a plurality of LEDs. Drive unit. The brightness of each of the LED driving units varies with an input voltage, and the plurality of AC voltages of different phases provide power to the plurality of LED driving units.

In a third embodiment of the present invention, an illumination device based on a light-emitting diode includes an AC power source, and a multi-phase AC power generator that generates a plurality of AC-to-AC voltages of different phases for rectifying the plurality of different phases. A plurality of rectifiers of alternating voltage, and a light emitting diode lighting unit. The brightness of the LED illumination unit varies with input voltage, and the plurality of rectified AC voltages of different phases are connected in parallel to each other to provide power to the LED illumination unit.

101:201:20N:401:402‧‧‧Lighting diode lighting unit

110:211:21N:411:412‧‧‧Rectifier

220‧‧‧Multi-phase AC to AC power generator

341:342:34N‧‧‧Lighting diode segment

351:352:35N‧‧‧ Voltage-controlled current limiter with three terminals

371:37k‧‧‧Lighting diode segment

381:38k‧‧‧ voltage-controlled current limiter with three terminals

390‧‧‧current source

420‧‧‧ Quarter phase AC to AC power generator

601:602:603‧‧‧Lighting diode lighting unit

611:612:613‧‧‧Rectifier

620‧‧‧Three-phase AC to AC power generator

1101:110N: 1201:1202: 1203‧‧‧Lighting diode AC drive unit

1120‧‧‧Multi-phase AC to AC power generator

1220‧‧‧Three-phase AC to AC power generator

1301:1401:1701‧‧‧Lighting diode lighting unit

1311:131N:1411:1412:1413:1711:171N‧‧‧Rectifier

1320‧‧‧Multi-phase AC to AC power generator

1420‧‧‧Three-phase AC to AC power generator

Figure 1 shows a conventional LED-based diode powered by an AC voltage source. A block diagram of the device.

2 shows a block diagram of a light-emitting diode-based lighting device including a multi-phase AC to AC power generator in accordance with a first embodiment of the present invention.

Fig. 3 shows an example of the light-emitting diode lighting unit in the first embodiment.

Figure 4 shows a block diagram of a lighting diode-based lighting device utilizing two different phases of alternating voltage, in accordance with a first embodiment of the present invention.

Figure 5A shows the voltage value of the AC voltage of the two phases in the illumination device based on the LED of Figure 4, and Figure 5B shows the voltage value of the rectified two-phase AC voltage.

Figure 6 shows a block diagram of a light-emitting diode-based illumination device utilizing three different phases of alternating voltage, in accordance with a first embodiment of the present invention.

Figure 7A shows the voltage value of the three-phase AC voltage in the illumination device based on the light-emitting diode of Figure 6, and Figure 7B shows the voltage value of the rectified three-phase AC voltage.

Figure 8 shows the brightness of the three LED lighting units in Figure 6, as the AC voltage of the three phases changes.

Figure 9 compares the brightness of a light-emitting diode illumination unit with a single-phase AC voltage as the power source, and the brightness of a light-emitting diode illumination device with three light-emitting diode illumination units powered by a three-phase AC voltage.

Figure 10 shows the crest factor of a light-emitting diode based illumination device powered by single-phase, two-phase, and three-phase AC voltages in accordance with the present invention.

Figure 11 shows a block diagram of a light-emitting diode-based illumination device including a multi-phase AC to AC power generator in accordance with a second embodiment of the present invention.

Figure 12 shows a block diagram of an illumination device based on a light-emitting diode using three different phases of alternating voltage, in accordance with a second embodiment of the present invention.

Figure 13 shows a block diagram of a light-emitting diode-based illumination device including a multi-phase AC to AC power generator in accordance with a third embodiment of the present invention.

Figure 14 is a block diagram showing an illumination device based on a light-emitting diode using three different phases of alternating voltage, in accordance with a third embodiment of the present invention.

Fig. 15A shows the voltage value of the three-phase AC voltage in the illumination device based on the light-emitting diode of Fig. 14. Fig. 15B shows the voltage value of the rectified three-phase AC voltage.

Fig. 16 is a comparison of the crest factor of the illumination device based on the light-emitting diode according to the first embodiment and the third embodiment in the present invention.

Figure 17 shows an example where there are N different phase AC voltages connected directly to the N rectifiers instead of using a multi-phase AC to AC power generator to generate AC voltages of different phases.

The present invention is provided with the accompanying drawings in which the invention may be further understood and The drawings illustrate embodiments of the invention and, together with

2 shows a block diagram of a light-emitting diode-based lighting device that utilizes a plurality of alternating voltages of different phases to reduce light flicker in accordance with a first embodiment of the present invention. here In an embodiment, the apparatus includes a multi-phase AC to AC power generator 220, a plurality of rectifiers 211-21N, and a plurality of LED illumination units 201-20N. The multi-phase AC to AC power generator 220 generates a plurality of AC voltages from an AC power source, each AC voltage having a different phase, and the different phases may be a uniform or uneven distribution. Each AC voltage is supplied to a light emitting diode illumination unit via a rectifier to generate a rectified AC voltage.

Figure 3 shows an example of a light-emitting diode lighting unit in Figure 2. The light emitting diode lighting unit comprises a first group of a plurality of light emitting diodes divided into a plurality of light emitting diode segments 341-34N, each of the light emitting diode segments having a positive end and a negative end, each connected To the negative end of the leading one of the light-emitting diode segments and the positive terminal of the subsequent one of the light-emitting diode segments. As shown in FIG. 3, the negative ends of each of the light-emitting diode segments are also respectively connected to a first connection end of a voltage-controlled current limiter 351-35N having three terminals, the current limiter The two terminals are applied with a bias voltage V ₁ -V _N , and the third terminal is connected to a common node in the light-emitting diode illumination unit.

As can be seen from FIG. 3, the LED illumination unit further includes a second plurality of LEDs connected between the common node and the current source 390. The second group of LEDs It is divided into a plurality of light emitting diode segments 371-37k. In order to simplify the description, each of the light-emitting diode segments only displays one light-emitting diode, and a plurality of voltage-controlled current limiters 381-38k having three terminals are connected in parallel with the plurality of light-emitting diode segments 371-37k. . Each of the voltage-controlled current limiters including three terminals has a first terminal connected to a 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 is connected to the first end of current source 390.

Figure 4 shows an example made in accordance with a first embodiment of the present invention in which a quarter phase AC to AC power generator 420 is utilized to produce two phases that are 90 degrees out of phase. AC voltage. 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 the two LED illumination units 401 and 402, respectively.

Figure 5A shows the voltage value of the two-phase AC voltage generated from a single-phase 220V AC power supply from the device of Figure 4, and Figure 5B shows the voltage value of the rectified two-phase 220V AC voltage. As shown in FIG. 4, in the example of the first embodiment, the two light-emitting diode lighting units 401 and 402 are respectively connected to the rectified two alternating voltages whose phases are different by 90 degrees.

Figure 6 shows another example made in accordance with a first embodiment of the present invention in which a three phase AC to AC power generator 620 is utilized to generate a three phase AC voltage. The three-phase AC voltage is connected to three rectifiers 611, 612 and 613, respectively, and then the rectified three-phase AC voltage is connected to three LED illumination units 601, 602 and 603, respectively.

Figure 7A shows the voltage value of the three-phase AC voltage generated by a single-phase 220V AC power supply. Figure 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 illumination units 601, 602 and 603 are respectively connected to three rectified 220V AC voltages having different phases.

Figure 8 shows the brightness of three light-emitting diode illumination units with the rectified three-phase AC voltage of Figure 7B as power, and the brightness of each of the light-emitting diode illumination units varies with the rectified AC voltage. Since the three rectified AC voltages have different phases, the brightness of each of the LED illumination units reaches a maximum value at different times. In the present invention, the total brightness of the light-emitting diode lighting device of the first embodiment is the sum of the brightness of each of the light-emitting diode lighting units, so the variation between the peak-to-peak values of the total brightness is reduced, and the lighting of the lighting device The flicker is also reduced.

FIG. 9 compares the brightness of a light-emitting diode lighting unit with a single-phase AC voltage as a power source, and the light-emitting diode lighting device of the first embodiment in which the rectified three-phase AC voltage is used as a power source in the present invention. brightness. It can be seen from FIG. 9 that the change between the peak value of the brightness of the light-emitting diode lighting device with the rectified three-phase AC voltage as the power source is compared with the light-emitting diode lighting with the single-phase AC voltage as the power source. The unit is very small and obvious.

The crest factor is often used as an index of the flashing of the light. In order to express the reduction in the flicker of the light, the present invention has studied the crest factor in the illuminating diode illuminating device of the first embodiment. The crest factor is defined as the ratio of the peak value of the light generated by an illumination device to the root mean square value. Figure 10 shows the light-emitting diode based on the rectified single-phase, two-phase, and three-phase AC voltages. The crest factor of the lighting device.

As can be seen from FIG. 10, the crest factor of the illumination device based on the rectified two-phase and three-phase AC voltages is significantly lower. The crest factor of a light-emitting diode-based illumination device powered by a rectified three-phase AC voltage is very close to the filament bulb. The crest factor of the illumination device based on the rectified single-phase AC voltage is higher than that of the fluorescent lamp. Figure 10 also shows a light-emitting diode illumination unit whose crest factor varies with the number of light-emitting diode segments.

11 shows a block diagram of a light-emitting diode-based lighting device that utilizes a plurality of alternating voltages of different phases to reduce light flicker in accordance with a second embodiment of the present invention. In this second embodiment, the apparatus includes a multi-phase AC to AC power generator 1120 and a plurality of LED output driving units 1101-110N. The multi-phase AC to AC power generator 1120 generates a plurality of AC voltages from an AC power source, each AC voltage having a different phase, and the different phases may be a uniform or non-uniform distribution. Each AC voltage is directly connected A light-emitting diode AC drive unit that varies in brightness as the input voltage changes.

Figure 12 shows an example made in accordance with a second embodiment of the present invention in which a three phase AC to AC power generator 1220 is utilized to generate a three phase AC voltage. The three-phase AC voltage is respectively connected to three LED driving units 1201, 1202 and 1203, each LED driving unit, comprising at least one set of LEDs connected in series, and another set of inversions In the series of light-emitting diodes, the two sets of light-emitting diodes connected in series are connected in parallel with each other.

To simplify the description, FIG. 12 shows that each of the LED driving units has only two inverted LEDs connected in parallel with each other. As can be seen from Fig. 12, each of the light-emitting diode AC drive units has a light-emitting diode that is turned on regardless of whether the AC voltage is positive or negative.

Figure 13 shows a block diagram of a light-emitting diode-based lighting device utilizing a plurality of alternating voltages of different phases to reduce light flicker in accordance with a third embodiment of the present invention. In this third embodiment, the apparatus includes a multi-phase AC to AC power generator 1320, a plurality of rectifiers 1311-131N, and a light emitting diode illumination unit 1301. The multi-phase AC to AC power generator 1320 generates a plurality of AC voltages from an AC power source, each AC voltage having a different phase, and the different phases may be a uniform or uneven distribution. Each AC voltage is passed through a rectifier to generate a rectified AC voltage, and all of the rectified AC voltages of different phases are connected in parallel to each other to supply power to the LED illumination unit 1301.

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

Figure 15A shows the three-phase AC to AC power generator 1420, a three-phase AC voltage generated by a single phase 220V AC power source. Figure 15B shows the voltage value of the rectified single phase 220V ac voltage and the voltage value of the rectified three phase ac voltage applied to the illuminating diode illumination unit 1401. Since there are three rectified 220V AC voltages of different phases connected in parallel to form a rectified three-phase 220V AC voltage, the voltage applied to the LED illumination unit 1401 is an absolute absolute of the rectified 220V AC voltages of different phases. The maximum value of the voltage value. Therefore, the change in the peak value of the voltage value is lowered, so that the light flicker of the light-emitting diode lighting unit is also reduced.

Figure 16 shows a crest factor of a light-emitting diode-based illumination device that supplies power by a rectified three-phase alternating voltage according to the first embodiment and the third embodiment, wherein the crest factor is based on the illumination device The number of light-emitting diode segments in the display is shown. As can be seen from Fig. 16, the crest factor of the illumination 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 generated by a multi-phase AC to an AC power generator from a single-phase AC power source, if The complex AC voltages of different phases are already available, and they can be rectified directly via the rectifier without the need to use multi-phase AC to AC power generators.

For example, in Figure 17, there are already N different phases of AC voltage, phase-1 to phase-N, directly connected to N rectifiers 1711-171N instead of using multiple phases. The bit is exchanged to an AC power generator to generate. All of the rectified multi-phase AC voltages are connected in parallel to each other and to the light-emitting diode lighting unit 1701.

Although the invention has been described above by way of a few embodiments, it is obvious to those skilled in the art that many modifications and modifications may be made without departing from the invention as defined below. Within the scope of the patent application.

201:20N‧‧‧Lighting diode lighting unit

211:21N‧‧‧Rectifier

220‧‧‧Multi-phase AC to AC power generator

Claims (21)

An illumination device based on a light-emitting diode using a multi-phase AC power source, comprising: a plurality of AC voltages of different phases; a plurality of rectifiers each connected to the plurality of AC voltages of different phases to generate a plurality of rectified AC voltages And a plurality of light emitting diode illumination units each connected to the plurality of rectified AC voltages; wherein a brightness of each of the plurality of LED illumination units changes with an input voltage . The lighting device of claim 1, wherein the plurality of alternating voltages of different phases are uniformly distributed in phase. The lighting device of claim 1, wherein the plurality of alternating voltages of different phases have a phase that is unevenly distributed. The lighting device of claim 1, further comprising: an alternating current power source; and a multi-phase alternating current to alternating current power generator connected to the alternating current power source to generate the plurality of alternating voltages of different phases. The lighting device of claim 4, wherein the multi-phase AC to AC power generator comprises a quarter-phase AC to AC power generator, and the plurality of AC voltages of different phases comprise two phases. AC voltages that differ by 90 degrees. The lighting device of claim 4, wherein the multi-phase AC to AC power generator comprises a three-phase AC to AC power generator. The illuminating device of claim 1, wherein each of the plurality of illuminating diode lighting units comprises: the first group of the plurality of illuminating diodes being separated into the first group of plural a light-emitting diode segment, wherein each light-emitting diode segment has a positive terminal and a negative terminal; a first plurality of voltage-controlled current limiters having three terminals, each of which has three terminals The voltage-controlled current limiter corresponds to one of the first plurality of light-emitting diode segments of the first group, and has a first connection end connected to a negative end of the corresponding light-emitting diode segment, The second connection end is connected to a bias voltage, and the third connection end is connected to a first common node in the illumination diode unit; the second plurality of light emitting diodes are separated into a plurality of second plurality a light emitting diode segment, wherein each of the light emitting diode segments has a positive end and a negative end, wherein a positive end of the first light emitting diode segment is connected to the first common node, and the last light emitting diode segment The negative end is connected to the light a second common node in the diode lighting unit; a second plurality of voltage-controlled current limiters having three terminals, wherein each of the three terminals has a voltage-controlled current limiter and the second Having a pair of light emitting diode segments corresponding to a plurality of light emitting diode segments, and having a first connecting end connected to a positive end of its corresponding light emitting diode segment, and a second biasing terminal is applied with a bias voltage a third connection end connected to the second common node; and A current source has a first end connected to the second common node and a second end grounded. A lighting device based on a light-emitting diode, comprising: a plurality of alternating voltages of different phases; and a plurality of light-emitting diode alternating voltage driving units respectively connected to the plurality of alternating voltages of different phases; wherein the plurality of light-emitting diodes The luminance of each of the light-emitting diode AC voltage driving units of the body AC voltage driving unit changes with the input voltage. The illuminating device of claim 8, wherein the plurality of alternating voltages of different phases are uniformly distributed in phase. The lighting device of claim 8, wherein the plurality of alternating voltages of different phases have a phase that is unevenly distributed. The lighting device of claim 8, further comprising: an alternating current power source; and a multi-phase alternating current to alternating current power generator connected to the alternating current power source to generate the plurality of alternating voltages of different phases. The illuminating device of claim 11, wherein the multi-phase AC to AC power generator comprises a quarter-phase AC to AC power generator, and the plurality of AC voltages of different phases comprise two phases. AC voltages that differ by 90 degrees. The lighting device of claim 11, wherein the multi-phase AC to AC power generator comprises a three-phase AC to AC power generator. The lighting device of claim 8, wherein each of the plurality of LED output voltage driving units comprises at least two sets of opposite light emitting diodes connected in parallel with each other, Each of the sets of light-emitting diodes comprises one or more light-emitting diodes in series or in series. A lighting device based on a light emitting diode, comprising: a plurality of alternating voltages of different phases; a plurality of rectifiers each connected to the plurality of alternating voltages of different phases to generate a plurality of rectified AC voltages, the plurality of rectified The alternating voltages are connected in parallel with each other; and a light emitting diode lighting unit is coupled to the plurality of rectified alternating voltages; wherein the brightness of the light emitting diode lighting unit changes with an input voltage. The lighting device of claim 15, wherein the plurality of alternating voltages of different phases are uniformly distributed in phase. The illuminating device of claim 15, wherein the plurality of alternating voltages of different phases have a phase that is unevenly distributed. The lighting device of claim 15, further comprising: an alternating current power source; and a multi-phase alternating current to alternating current power generator connected to the alternating current power source to generate the plurality of alternating voltages of different phases. The lighting device of claim 18, wherein the multi-phase AC to AC power generator comprises a quarter phase AC to AC power generator, and wherein the plurality of AC voltages of different phases comprise two phases AC voltages that differ by 90 degrees. The lighting device of claim 18, wherein the multi-phase AC to AC power generator comprises a three-phase AC to AC power generator. The illuminating device of claim 15, wherein the illuminating diode lighting unit comprises: the first group of the plurality of illuminating diodes being separated into the first group of the plurality of illuminating diode segments, wherein each illuminating The diode segment has a positive terminal and a negative terminal; a first plurality of voltage-controlled current limiters having three terminals, wherein each of the three voltage-controlled current limiters and the first group Corresponding to one of the plurality of LED segments, the first connection end is connected to the negative end of the corresponding LED segment, and the second connection is connected to apply a bias voltage. The third connection end is connected to a first common node in the illumination diode unit; the second plurality of LEDs are separated into a second group of a plurality of LED segments, wherein each of the two LEDs The pole body segment has a positive end and a negative end, wherein a positive end of the first LED segment is connected to the first common node, and a negative end of the last LED segment is connected to the LED illumination unit a second common Point; a second group comprising a plurality of current limiter control voltage of the three connections, each of which contains a voltage-controlled three connections of the current limiter and the second set of plurality of light-emitting diode segment Corresponding to one of the LED segments, and having a first connection end connected to the positive end of its corresponding LED segment, a second connection connection is applied with a bias voltage, and a third connection end is connected to the above a second common node; and a current source having a first end coupled to the second common node and a second end grounded.