ENERGY REQUIREMENTS & SUPPLY
Major part of energy for power supply will be obtained from solar energy, abundant and accessible in space. It would be the main source of hybrid power system. The secondary sources are to be: electrochemical cells and rechargeable DC batteries.
Two coaxial counter-rotating modules and the common rotation generator module are suitable to carry sun tracking solar arrays. In some configurations solar arrays attached to one module can be obstacles for efficient solar power generation on other solar arrays attached on the other modules because of their proximity, rotation, and size. To avoid this, and especially to isolate solar arrays from the craft’s rotation, the central rotation (but not rotating) generator module will carry high-power solar arrays directed toward the Sun. The central non-rotating module with the solar arrays attached will be a kind of solar power satellite (SPS) and wireless transmitter of microwaves or laser beams to rectennas or other receivers attached on the rotating modules.
The best option for solar arrays is the innovative high-TRL and high-power flexible round panel array with circular deployment, revolutionary unfurling mechanism, and cutting-edge materials, which provides high specific power, lightweight, high stiffness and strength, and small stowed volume. Another favourable options are thin-film or flexible rollout array and concentrating arrays.
Generated solar energy will be transmitted from the central non-rotating module to the coaxial counter-rotating modules by wireless power transfer (WPT) via microwave beaming or magneto dynamic coupling. In both cases the central module acts as SPS and contains power source and transmitters for WPT while both rotating modules contains receivers and loads.
In the case of WPT by high intensity power beaming, power can be transmitted via microwaves. Although considered long-range technique, it also can be efficiently applied as short-range technique. The central module is power source and contains magnetrons as transmitters for WPT directed towards the rotating modules that contain receiving systems with rectennas. In the case of high intensity power beaming, 50% efficiency has been already achieved at the receiver. In some cases it is up to 80%. Mutual coupling between transmitting antennas and receiving antennas occurs in short distance. The final output electrical power density at the receiver has reached 20 W/cm2.
There is a plenty of space inside the rotation generator module itself, just as there is plenty of space inside the rotating modules. All this free space is available for storage of electrochemical and regenerative fuel systems and, also, for power management and distribution system. Combining these power sources with the solar power obtained from solar panels and solar arrays, EDGG electric power system becomes fully hybrid.