Design of LQR control law for hybrid electric propulsion system based on engine IOL

With the rapid development of the aviation industry, the demand for air traffic has been growing steadily, and the trend of electric power for aircraft has also taken shape. Due to the relatively low energy density of current batteries, hybrid electric propulsion represents a more feasible option under the present technological conditions. This paper conducts research on fixed-wing vertical take-off and landing (VTOL) air-craft, adopts a series hybrid electric propulsion system(HEPS), finds the efficient working point of the engine based on the universal characteristic curve of the engine, and thus establishes the ideal operating line (IOL) of the internal combustion engine. A state-space model of the hybrid electric propulsion system has been established, and a control law based on Linear Quadratic Regulator (LQR) has been designed. Simulation results indicate that the proposed LQR control law enables the engine to operate along the ideal working line, thereby enhancing the fuel economy of the hybrid electric propulsion system.