RU168569U1 - LED light source powered by an unstable three-phase AC network - Google Patents

Abstract

An LED lighting source powered by an unstable three-phase AC network refers to lighting engineering and is intended for use as part of LED lighting devices operating from an unstable three-phase AC network. The technical and economic results of the claimed solution are a significant reduction in cost, increased reliability, reduced weight and dimensions of drivers for LED illuminators, as well as increased efficiency. The LED lighting source includes a three-phase voltage rectifier (first voltage source), a second adaptive voltage source, a voltage sensor of the first voltage source, a group of series-connected LEDs with a passive current source, the first and second voltage sources are connected in series and sequentially, and their total voltage is included a group of LEDs connected in series with a passive current source, while the voltage of the adaptive (second) voltage source is controlled Xia sensor first voltage source so that the total voltage of the two voltage sources is always constant and depends on the range of instability and AC voltage on an adaptive voltage source. 3 ill.

Description

Technical field

The solution relates to lighting engineering and is intended for use as part of powerful professional LED illuminators.

State of the art

The main solution of LED lighting systems is a typical frequency-conversion power supply that generates a stabilized current to power the LEDs, and the voltage at the terminals of this power supply corresponds to the total voltage on the LEDs and, as a rule, has a low value from 12 V to 120 V and only in some cases higher. At the same time, if high light intensities (high power) are needed for illuminators that are used in professional technology (powerful High Bay, for cranes, high rooms, powerful floodlights for lighting large areas (stadiums, airfield areas, etc.)) , then such solutions are not justified, since the low reliability of power sources, due to the presence of electrolytic capacitors in them, high cost, large weight and dimensions hinder the development of LED lighting in many industries. Further, at high capacities and low output voltages, the necessary currents sharply increase for the implementation of powerful illuminators, and large currents impede the transmission of energy over a distance, since losses in the wires increase. So, when lighting stadiums, spotlights are usually located at a considerable distance from the cabinets with power sources and are installed in places with the help of climbers. In such devices, as a rule, two wires with a voltage of 700 V go from the source to the searchlight, because the power of the spotlights is from 700 to 2000 watts. Also, at present, in the innovative LED lighting, a high level DC voltage has already begun to be applied (more than 700 ... 800 V). In other words, for the design of high-power lighting, especially for those devices that are in inaccessible places (towers, towers, pillars of external lighting, lights of high industrial buildings, spotlights, etc.), the use of increased voltages and even power sources is quite acceptable, uninsulated from the industrial network.

The technical and economic results of the claimed solution are a significant reduction in cost, increased reliability, reduced weight and dimensions of drivers for LED illuminators, as well as an increase in their efficiency by 3 ... 4.9% with respect to the best drivers currently known.

Decision Disclosure

The claimed solution can be characterized by the following set of features.

A LED lighting source including a three-phase voltage rectifier (first voltage source), a second adaptive voltage source, a voltage sensor of a first voltage source, a group of series-connected LEDs with a passive current source, characterized in that the first and second voltage sources are connected in accordance with and in series , and their total voltage includes a group of LEDs connected in series with a passive current source, and the voltage of the adaptive (second) source is voltage is controlled by the voltage sensor of the first voltage source so that the total voltage of both voltage sources is always constant and depends on the range of instability of the AC network and voltage on the adaptive voltage source.

The basis for creating high-voltage drivers is a 6-diode rectifier of a three-phase AC network, which in nominal value gives 540 ... 560 V (220 ... 230 V) peak voltage with ripples of about 5-6% without any capacitors. However, the instability of the industrial network can be more than ± 10% and therefore some measures should be taken to eliminate the influence of this instability on the light characteristics of the illuminator.

In FIG. 1 shows the power supply circuit of LEDs from two voltage sources controlled by a voltage sensor, on which:

U ₁ - the main voltage source is unstabilized (this is the rectified voltage of a three-phase network, in the case of a three-phase network, the voltage range is from 486 V to 594 V);

U ₂ is a constant voltage from an adaptive IPAD power source;

IPAD - adaptive voltage source;

D.T. - a control signal sensor for IPAD control;

C is the output capacity of the IPAD;

D ₁ - Dn - LEDs;

I ₁ - current source (passive).

Power supplies are connected in series and LEDs are connected in series with the current source in their total voltage. The adaptive voltage source is controlled from a voltage sensor D.T. with a rectifier three-phase network. The higher the voltage from the rectifier, the lower the voltage on the IPAD and vice versa. If the network instability is ± 10%, the voltage after the rectifier will be in the range of ~ 485 V ... 595 V. If we take the minimum voltage on the IPAD equal to 20 V, then the voltage range that will be on the IPAD 595-485 = 110 V, i.e. from 20 to 130 V, and the total voltage will always be 615 V. The LEDs with the current source I ₁ will be turned on to this voltage. If the required current for the LEDs is assumed to be 0.7 A, then the total driver power will be Roc. = 615 × 0.7 = 430.5 W. The power taken from the three-phase network will be within

from 485 V × 0.7 A = 339.5 W

up to 595 V × 0.7 A = 416.5 watts.

IPAD power will be within

from 20 V × 0.7 A = 14 W

up to 130 V × 0.7A = 91 W, i.e. IPAD power is only 21% of the total power of the entire driver.

In FIG. Figure 2 shows a similar driver circuit, but the feedback on the IPAD control is taken from the current source, which has significant advantages compared to the previous circuit. The minimum allowable voltage at the current source is supported, which allows to achieve maximum efficiency (maximum efficiency). At the same time, automatic compensation of the voltage spread across the LEDs is achieved, which is inevitable even for one party, and even more so for LEDs from different parties.

In FIG. 3 shows a driver circuit with an active current source, powered by a single-phase AC network, on which:

U ₁ - rectified voltage of a three-phase network;

U ₂ - voltage at the output terminals of the active current source;

3 - active current source powered by a single-phase alternating current network;

4 - a group of LEDs.

As an IPAD, a standard active current source is used, powered from a single-phase, three-phase network or from a rectified voltage of a three-phase network. An active current source is a current source that is independently powered. If the efficiency of the current source is η ₁ = 0.92 at a power of 91 W (the worst case scenario), then the overall efficiency of the driver will be

At the rated operating point (at rated voltage), the power of the current source will be 38.5 W with an efficiency of ~ 0.9, then the driver's efficiency will be

The best performance for a standard 430 W driver can be on the order of 0.95, i.e. the gain is more than 4.0%, excluding the drop in power on the rectifier bridge. Since the driver load is LEDs, which can be considered an active load, the power factor will also be close to unity (even if the power factor PF = 0.97 for the current source, then with a total power of 430 W it will be close to unity). Harmonic components will be determined only by the current source, which at its rated power of 38.5 W is lower than the requirements of the standard, and for a power of 430 W they will be negligible. There is another advantage of the proposed schemes - there is no need to balance the phases, since the main power consumed by the driver is automatically balanced, and if the power source is supplied from the rectified voltage of a three-phase network, then 100% load balancing for the phases is implemented.

The LED lighting source, which includes a three-phase rectifier connected to a three-phase AC network, an additional power source connected in series with the voltage of the three-phase rectifier, and a group of series-connected LEDs is included in their total voltage. If the additional source is a voltage source, then it must be adaptive to changes in voltage on the rectifier and a passive current source is switched on in series with the LEDs. If the additional source itself is an active current source, then the additional current source is not installed.

Claims (1)

An LED light source powered by an unstable three-phase AC network, including a three-phase voltage rectifier — a first voltage source, a second adaptive voltage source, a voltage sensor of a first voltage source, a group of series-connected LEDs with a current source, characterized in that the first and second voltage sources are turned on according to both series and their total voltage, a group of LEDs is connected in series with a current source, and voltage a The adaptive voltage source is controlled by the voltage sensor of the first voltage source so that the total voltage of both voltage sources is always constant and depends on the instability range of the AC network and the voltage on the adaptive voltage source.

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