Abstract: An aircraft emergency power unit (EPU) includes a battery powered subsystem that replaces toxic hydrazine fuel use. The battery of the battery powered subsystem is utilized to supply power to an aircraft electrical system in the event of a failure of the EPU turbine-powered generator. The battery of the battery powered subsystem is also utilized to supply power to an electric hydraulic motor pump in the event of a failure of the EPU turbine-powered hydraulic pump (or to augment the output of the EPU-turbine-powered hydraulic pump). The battery of the battery powered subsystem is capable of simultaneously powering the electrical system and the electric hydraulic motor pump or of powering either one of the electrical system and electric hydraulic motor pump independently based upon aircraft fault conditions. Intermittent operation of the electrical system and/or the electric hydraulic motor pump in an intermittent fashion on an as-needed basis is also possible.

Abstract: An electronic power factor corrector for a main equipment is employed to correct the power factor of an accessory to the main equipment. A voltage signal is generated in accordance with the rectified current input to the accessory. This voltage signal is summed with a voltage signal in accordance with the sampled input current or the current in the return current path from the main equipment. The summation signal is fed to a differential amplifier where it is compared with a reference signal in accordance with the current input to the main equipment. The output of the differential amplifier is fed as a control signal to a switching current source circuit which controls the current drawn by the main equipment and accessory to maintain the power factor close to unity.