DALI Emergency Light Unit with DC Bus Charging
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Solution Overview
Problem
Emergency lighting units in DALI-standard lighting systems require a connection to the AC mains for recharging, limiting their installation flexibility and increasing costs due to the need for rectification and potential mains access issues.
Innovation Solution
An emergency light unit is designed to be powered by a low-voltage DC bus voltage for charging, allowing it to operate independently and reducing the need for AC mains connection, combined with a DALI control device to manage increased current draw within the DALI standard limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If emergency light units are connected to AC mains for recharging, then reliable power supply is ensured, but installation flexibility is reduced and costs increase due to rectification requirements
Solution Approach 1:
The emergency light unit is designed to perform multiple functions: it can recharge from both AC mains voltage and DC bus voltage. The operating circuit automatically detects and adapts to the available power source, making the device universally compatible with different power supply configurations without requiring separate designs for mains-powered and bus-powered installations.
Solution Approach 2:
The charging circuit is designed to accept different voltage parameters - it can process both higher AC mains voltage (requiring rectification) and lower DC bus voltage (9.5-22.5V). The operating circuit modifies its operation based on the input voltage type, enabling the same hardware to reliably charge from either source while adapting to the specific electrical parameters of each power source.
2Power
If emergency light units are connected to AC mains, then sufficient charging power is available, but device complexity increases due to rectification circuits
Solution Approach 1:
The rectification function is extracted as an optional component rather than a mandatory element. When DC bus voltage is available, the rectification circuit can be completely bypassed, reducing the active components in the charging path. This allows the system to maintain high charging power capability when needed while minimizing circuit complexity when DC input is used.
Solution Approach 2:
The charging circuit configuration is made dynamic - it automatically reconfigures based on the power source type. The operating circuit switches between mains rectification mode and DC bus charging mode, dynamically adjusting the circuit topology to match the input source. This dynamic adaptation allows the system to use simpler circuit paths when DC voltage is available while maintaining full power capability when AC mains are used.
3Use of energy by moving object
If DALI control devices draw increased current from the bus, then emergency light recharging is enabled, but current draw limits of the DALI standard are violated
Solution Approach 1:
The emergency light unit is merged with a DALI control device (such as a sensor module) to form a combined unit. This allows the device to legitimately draw higher current from the DALI bus under the exception provisions for control devices while simultaneously performing emergency lighting recharging. The sensor functionality provides a valid reason for increased power consumption that complies with DALI standard exceptions.
Solution Approach 2:
The combined unit performs multiple functions: sensing (light, presence, motion, or IR detection) and emergency lighting recharging. This multi-functionality justifies the higher current draw from the DALI bus, as the device falls into the category of DALI control devices with additional functionality beyond simple lighting control, thereby complying with the standard's exception provisions for multi-functional control devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the emergency light unit to recharge without AC mains access, reducing installation constraints and manufacturing costs while maintaining compliance with DALI standards, ensuring reliable emergency lighting.
Implementation Method 1
an emergency light unit (15) with at least one emergency light source (16), in particular at least one LED, a rechargeable store for electrical energy (17) and an operating circuit (15a)
Data Source
Figure 1~3
AI summary
The invention relates to an emergency light unit for a lighting system, in particular an emergency light unit designed according to the DALI standard, having the following features: The emergency light unit is connected to a bus (2) of the lighting system, to a rechargeable store (17) of electrical energy, and to emergency lighting means (16).