|The Benefits of Low-Voltage DC Power Distribution for LED Lighting (LumaStream)
Lighting companies are struggling to transition from traditional lighting sources to providing reliable, energy efficient, high-performance dimming-control solutions utilizing solid-state lighting (SSL) technology. Typically, there is a lack of technical knowledge
Dimming quality influences the quality of the entire lighting system. Many available dimming solutions have either a noticeable flicker during changes in light intensity or a limited dimming range of 10% to 100% where light output drops abruptly from 10% to 0. In addition, the proportional energy savings benefits of dimming are eroded by inferior power efficiency at lower power loads.
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This power and control solution typically combines disparate components such as remote mounted AC/DC power sources, a dimming control interface, and current drivers. Current drivers located within the LED fixture contribute additional heating, reducing the longevity and light output performance of the fixture. Furthermore, the current driver and control/dimming interface is located within every LED fixture increasing the wiring complexity and component count and therefore reliability of the entire SSL system (see Figure 2).
FIGURE 2: Kluged SSL DC Low-Voltage Distribution System with Dimming
3. The optimal methodology realizes that energy saving potential, reliability, and dimming performance of an SSL system is directly related to the power conversion and dimming/control design. The technology solution illustrated is an integrated “3 in 1” Trinity platform that combines the blocks of an AC/DC Power Converter with power factor correction, multi-channel current drivers and a control-dimming interface.
The Trinity platform is intended for remote mounting in a wiring cabinet, closet, rack
The Trinity platform offers superior power conversion efficiency, more intelligence, and potentially lower costs for installation and dimming control. The cost saving and technology benefits with this approach are significant (see Figure 3).
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FIGURE 3: Low-Voltage DC Distribution SSL System Using Trinity Platform With Dimming
Installation Cost Savings Potential
A major cost benefit comes from the typical AC voltage distribution approach where AC voltage is distributed by expensive Class 1 electrical wiring infrastructure compared to low voltage DC Class 2 distribution which is less expensive and easier to install. From a safety perspective, the DC approach is classified as a low voltage, energy limited DC distribution system.
Installation of the Trinity platform early on in the wiring to the LED fixtures as part of a low voltage DC distribution system reduces the amount of conduit or armoured cable
The Trinity platform includes a dimming/control interface to control and dim up to 12 output current drivers and up to 24 LED fixtures with a single wiring dimming interface connection. This approach reduces the wiring complexity and cost compared to an AC voltage distribution method where a discrete wiring connection for dimming control needs to be made to each LED Driver connected in close proximity to every fixture.
Similarly, in the case of a kluged low voltage DC system where the current drivers and dimming interface are embedded within the LED fixture, there is a significant cost and wiring complexity since a wiring connection for dimming control also needs to be made to every LED fixture.
Maintenance Cost Savings and Safe Access Potential
The remote mount capability of the Trinity platform enables safe accessibility for maintenance personnel in secure locations such as prisons and psychiatric hospitals or in hazardous locations. Its inherent safety with a low voltage, energy limited power distribution approach also enables the safety of end users.
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Upgrade Savings Potential
Future generations of LED light engines are expected to provide better efficacies in terms of higher lumens/watt.
In the case of a typical Class 1 AC Voltage distribution installation, a future upgrade would require every LED engine and every LED Driver whether located within the fixture or
The Trinity platform incorporates microprocessors to provide numerous configuration options for drive currents (350mA to 1400mA), dimming-control protocols and channel configuration that facilitates adaptation to the newest generation of LEDs.
The integrated power conversion stages within the Trinity platform utilize digital feedback control in order to optimize energy efficiency. This approach provides superior energy efficiency compared to a kluge solution over a wide range of load conditions such as 25%, 50%, 75%, and 100% with an average efficiency over these load conditions exceeding 80% (see Figure 4 and Figure 5).
FIGURE 4: Kluge vs. Trinity Platform
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FIGURE 5: Trinity6 Efficiency While Dimming
Key Performance Benefits