Natural disasters can strike across the globe and the restoration of communications is crucial for emergency personnel to meet the urgent needs of victims as well as restoring the availability of vital services like food, drinking water, and electricity.
A Japanese engineering firm, Fukaden Corporation, is supporting this humanitarian endeavor by providing power to base stations for mobile communications which are integrated to power their high-powered drones that are tethered. These lightweight, mobile drones can be used by first responders in order to provide instant communication once they arrive. First responders get the assistance they require to make informed decisions and communicate rapidly.
In collaboration with the major telecoms providers within Japan, Fukaden has conducted demonstrations with the Power Control BOX II Main Power Supply Unit, which is able to supply power via an untethered cable that connects the drone. It allows the power of 1 kW to be delivered for up as 150 meters. It can also be scaled easily using units that run in parallel , bringing the power to 3kW that can provide cellular service up to 10km in size.
Higher voltage makes it easier to make thinner and lighter cables
The biggest drawback with drones with tethers is the size as well as the weight of power cables. A long, bulky cables add weight, causing more drag, which demands more power, and reduces the possibility of adding new functions to drones like the sensors and high-quality video cameras.
Fukaden drones require between 1kW and 5kW of power. raising the voltage of supply from 24V to 337V cuts the current of supply by 15x.This makes it easier to use an ether cable that is thinner that reduces the weight of the tether cable by nearly 10-fold, from just 125g down to 11.1g per mile.
The 370V voltage that is running through the drone needs an extremely dense, light DC-DC converter module that can be fitted into the drone to lower the power back to DC24V, which is required to power the motor.
The original Fukaden DC-DC high-voltage converter was large and took up plenty of space. The company therefore searched for a smaller, lighter DC-DC converter. They substituted the big converter with an Vicor DCM power unit.
Figure 2: Fukadenpower supply unit for tethered drones “Power Control BOX II Main Power Supply Unit”(back)and a part of power unit, mounted two of Vicor DCM (right)
Vicor DCM Vicor DCM, an DC-DC isolated which utilizes high-frequency, ZVS (ZVS) technology. It is distinguished by high efficiency in conversion and high output power density. Utilizing the DCM reduced the size by 75 percent and reduced the weight by nearly 50.
The development of higher-performance drones for communication
Next-generation Fukaden communication drone will require as much as 9kW in power. With the use of more power at higher voltages (DC 700V) along with thinner cabling as well as upgrading the system to 3 Vicor BCM(r) bus converters running in series, Fukaden was able to increase the power to 4.5kW.To further increase power to 9kW 2 Fukaden Power supply devices could be linked in parallel.
Figure 3: Fukaden’s next generation communication station requires up to 9kW. Using higher voltage power (DC 700V), thinner cabling and an array of three Vicor BCMs in parallel Fukaden was able to easily scale the power to deliver better performance. With the added power, the drone can fly for 92 hours and maintain a communication area diameter of 10km.
With the additional power it can be flying for up to 92 hours, and keep an area of communication that is 10km. The increased performance also allows the base station perform better in all forms of weather.
The lightweight and compact module for power made it simple to develop and expand power. It also made it easy to install bases for drones to be used for crucial, life-saving, mission-critical deployments. Fukaden portable base stations are fast becoming the most vital equipment to first respond when natural disasters hit. The portability and versatility can be an asset for the relief efforts in Japan as well as around the globe.
