Abstract: To satisfy the designated multi-day unintermittent flight of solar-powered aircraft, drawing on the in-situ system state parameters including altitude, photovoltaic power output, battery residual capacity, etc., a study on power allocation between power battery charging-and-discharging and electric-propulsion system input is carried out. Based on the real-time power balance, the adopted strategy maximizes the photovoltaic resource utilization by making the best of photovoltaic midday peak power to feed the climbing and charging in the meantime, and taking up total photovoltaic output to the postmeridian gliding. The strategy also minimizes the composite energy loss by maintaining the gliding at a stand-by power during the photovoltaic effective output shortage. The method can increase the mission success rate of multi-day unintermittent flight under the conditions of predefined night flight altitude, or enlarge the combination range of the flight altitude, latitude, date, and payload weight (or payload power-consumption), so as to optimize the adaptability of the solar-powered aircraft.

Key words: solar powered aircraft, UAV, energy management, power allocation, endurance performance, altitude profile