Abstract High speed electrical machines are central in replacing existing systems in aircraft with electrical counterparts. An integrated, fault tolerant, permanent magnet machine and drive is considered. Aerospace systems require high power density and high reliability from systems. Availability may be increased by adding fault tolerance to the system design and power density may be increased by integration of subparts. Much design flexibility can be found when system subparts are designed jointly. To aid system integration losses are to be kept low. This can be done by selection of a topology which yields low losses, amongst other factors. A three phase inverter and full bridge inverters with bipolar PWM, unipolar PWM and Phase Shifted Full Bridge topologies are investigated, for which switching and conduction losses are calculated. Low frequency modulation is shown to be possible with the use of a Phase Shifted Full Bridge topology. This strategy also enables the use of IGBT devices in high speed machines where switching speeds limits the power level and rotational speed of such fast rotating machines.@en

The integration of an electrical machine and power electronics promises many benefits, the largest being an increase in power density. The use of system integration may lead to an increase in loss density and local or component temperatures. For this reason much attention needs to be paid to the thermal design aspects of the system. In the aerospace industry weight and reliability are of significant importance. In this paper the integration of a permanent magnet machine and power electronics into a single structure with joint thermal management is investigated. An overall goal of 2 kW/kg is set for system power density. Additionally in this paper fault tolerance is introduced into the design. This will allow the system to continue functioning should a single electrical fault occur. Principle faults are identified and discussed. A 50 kW, 6 phase, 8 pole permanent magnet machine is presented with a rotor speed of 50 krpm. A symmetrical phase shifted full bridge is used to drive the permanent magnet machine, aiding the functionality of fault tolerance and enabling the use of soft switching. A mathematical model for both machine and power electronics is created and used to calculate phase currents and losses in the machine and power electronics. Finally, spatial integration and thermal management concepts are presented and analysed.@en

Electrical machines used in aerospace applications require fault tolerance to ensure high availability. This frequently includes partitioning, increasing the number of machine and drive phases. Fitting every partitioned phase with a localised controller increases the autonomy of each phase. Using the magnetisation of the rotor as reference, minimal communication between phases is required. An overhead controller is used for open loop startup. Due to the high rotor speed, sensorless control is implemented to avoid reliability problems with encoders. Low frequency commutation is used to lower computational effort and converter loss.@en