Stability analysis of motor drive interactions in aircraft electrical systems

More Electric Aircraft are currently being developed so that in the future all non-propulsive power on an aircraft can be provided by the electrical system. In this electrical system, it is expected that several motor loads will run in parallel from a single DC bus. The paper will investigate the interactions between five motor loads connected to a common DC bus, paying particular attention to the effects of the line impedance on the stability of the system, and how this interacts with any capacitance in the input filters to the motor drive loads. Based on the results of the tests carried out, guidelines to ensure the stability of a multiple load system are presented. To achieve this, a generic model for a motor load is proposed. Five of these motor loads are then connected to a DC bus and the stability of this system has been tested. The motor parameters have been scaled to represent models of different sizes, and they have different input filters. The impedance of the line has been included.