**2. Introduction of the System Specification**

A high-power-rating motor drive system for aerospace applications was assumed in this paper. The specification of the drive system is defined in Table 2. The power demand of the motor was 60 kW. Although in current MEA power systems, a 230-V AC grid is the only choice of power supply for high-power converters. However, in the near future, a 460-V AC grid becomes possible, which makes the DC link voltage up to ±400 V. With the help of this high-voltage DC link, 460-V AC motors can be selected to lower AC cable loss and decrease both cable and motor weights. According to the specification, the nominal AC currents on both the rectifier side and the motor side, the modulation index M, and the power factor were calculated, which is also shown in Table 2. Because that a 200% overloading capability was required by the motor side, 300-A IGBT modules were selected for converters on both sides. The switching frequency was set to be 15 kHz, which is a common selection in converter design for an aerospace motor drive.


**Table 2.** Specifications of converters for motor control.

All these specifications present several challenges for the to-be-designed power electronic converter, which are listed as follows:

• High power density and high efficiency: The power electronic converters are the main heavy part of the drive system. Evaluation and comparison should be carried out to show which topology is better in terms of the power modules' size and weight. The efficiency is also important, since it also affects the size of the thermal system. On the other hand, the high temperature created by high-power losses affects the reliability of the converters.

