Hybrid solar-RF energy harvesting systems for electric operated wheelchairs

Abstract

Over the decades, with the advancement of science and technology, wheelchairs have undergone remarkable changes, such as controlling an electrical wheelchair by using brain signals. However, existing electrical wheelchairs still need improvements in terms of energy management. This paper proposes an hybrid Solar-Radio frequency (RF) harvesting system able to supply power for the continuous and effective operation of electrically powered wheelchairs. This system can simultaneously harvest power from RF and solar source that are both available in the surrounding environment. A maximum power point tracking (MPPT) and a boost converter are exclusively employed for the standalone solar system while the standalone RF system is equipped with a 9-stage voltage multiplier (VM). The voltage level for the charging process is obtained by adding the output voltage of each source. In addition, a current booster and a stabilizer are used to reach the required level of current and pin the charging voltage to a stable level, respectively. Simulation results show how the hybrid system is better and more stable when the boost current and stabilizer are used in the charging system. Moreover, we also provide some analytic results to prove the advantages of this system.