A Dual Three-Phase DC-Link Inverter Prototype Powering a Redundant Space Robotics Motor Drive

Like their industrial counterparts, space robotics motor drives require a DC-link inverter to convert the spacecraft's DC-bus voltage into a three-phase AC rotating field. The designer of a space grade inverter needs to balance various opposed design objectives. Achieving a high level of operational reliability, including dependable fault monitoring capabilities is essential, while simultaneously keeping design complexity as low as possible. Based on the preliminary results of an earlier on-orbit-servicing project study initiated by German Aerospace Center DLR, the Institute of Robotics and Mechatronics has developed an engineering prototype of a robotic arm for space. This paper describes the design and initial operation of the robotic system's dual three-phase DC-link inverter, which powers the robotic motor drives. It summarizes some lessons learned during the development process and indicates the next steps required to further test and qualify the inverter for a planned in-orbit demonstration of European space robotics servicing technology.