This paper presents a multiphase permanent magnet synchronous motor (PMSM) for the more electric aircraft propulsion. The stator winding of the motor is composed of multiple sets of multiphase windings with different parameters. The purpose of the motor design is to modify the distribution of the high efficiency area of the motor by reasonably matching the winding parameters of each set, thereby making the motor more suitable for the working condition of more electric aircraft and improving the working efficiency of the motor. This paper analyzes the selection principle of slot-pole combination and the influence that asymmetric windings have on the motor magnetic field. Three basic matching modes are proposed: equal torque matching, equal power matching and equal speed matching. The motor model is established, with the external characteristics, efficiency and dynamic response of different matching modes being compared and analyzed. The results show that equal torque matching and equal speed matching can reduce the total loss of the motor in a complete flight working condition, whereas equal power matching is not suitable for more electric aircraft.

Although many permanent magnet synchronous motors (PMSMs) are used as the driving source for aerospace applications, the motor and converter are not integrated. This leads to large volume and low power density of the system. This article proposes an SiC-based integrated modular motor drive (IMMD) as a potential solution, in which the SiC converter is placed at the end of the stator core of the motor. The converter is directly connected to the end-turn windings of the motor so as to reduce the wiring cable losses, with the motor and converter being cooled by an integrated water-cooled housing, significantly reducing the weight of the system and improving the power density. First, the topology of a five-phase IMMD is briefly introduced. Then, the influence of the number of slots on the output performance of the motor is analyzed with the aim of improving the power density of the system. Because the system integration will cause the loss density of the motor to sharply increase, this will thereby cause the local temperature of the IMMD to be higher. A detailed analysis and calculation of the thermal design will be required to improve the reliability of the system in high-temperature environments. The skewed rotor method is adopted so that the torque ripple of the fractional-slot motor is suppressed in the high-speed region. The results show that these methods can increase the power density of the IMMD and expand the speed range of the motor so as to meet the needs of different stages during the whole flight of more electric aircraft.

The pulsed alternator (PA), a kinetic energy pulsed power supply, has been developed during the past four decades for application to the electromagnetic launchers. The principles and characteristics of PAs, including topologies, compensation type, and operation mode are described here. The development history of PAs is introduced with a description of the research prototypes that have been developed. Technical improvements have occurred during the development of each generation of PAs. Three basic design aspects, electromagnetic, thermal, and structural design of PAs are presented. The challenges and prospects for PAs are presented, concluding with future trends.

Although many PMSMs are used as the driving source for electric vehicle motor drive systems, there is still a gap compared with the power density index in the DOE roadmap. Considering that the motor occupies a large space in the motor drive system, it is of great significance for the system to increase the motor power density and thus reach the system power density index. This article starts with electrical machine basic design theory and finds the motor power density influence factors. Guided by the theory and considering motor driver influence, this article proposes a high power density motor for electric vehicle integrated motor drive system. The motor for the system is a five-phase interior permanent magnet synchronous motor (IPMSM) with a double-layer rotor structure and fractional slot distributed winding. Compared with Ver1.0 motor, Ver2.0 motor power density improves significantly. In order to prevent damage from excessive temperature, a temperature field solution model is established in this article to compare the cooling effect and pressure loss of the spiral, dial, and axial water jackets. The temperature is checked at motor main operating conditions using an optimal cooling structure. Finally, the power density of the designed Ver2.0 motor reaches 3.12 kW/kg in mass and 15.19 kW/L in volume.

Compensated pulsed alternator (CPA, Compulsator) is a pulsed power supply with high power density and energy density. The principles of electromagnetic shielding and magnetic flux compression are used to provide a huge pulse current to the load. In order to reduce the mass or volume of the alternator and increase the storage density, high-strength composite materials are used in the air-core CPA. They are the preferred sources of modern electromagnetic weapon systems because of their merits. A high-speed air-core permanent magnet CPA (PMCPA) was presented in this paper with Halbach array PM topology of the rotor. The heavy external excitation source was not needed, so the volume and mass of the entire discharge system was reduced. Due to the special topology of air-core PMCPA, the parameters of the PMCPA were designed based on the theory of electromagnetic field analysis, numerical, and analytical methods. The finite element method simulation model is built based on the dimension parameters of CPA. The discharge process is simulated by Ansys Maxwell to optimize the performance of PMCPA.

This paper investigates the choice of pole spacer materials for a high-speed surface-mounted PMSM based on the temperature rise and thermal stress. For a rotor without copper shield, the influences of pole spacer materials on the rotor losses, temperature rise, and thermal stress are analyzed. After that, the rules for selecting pole spacer materials are concluded. For a rotor with copper shield, the effects of copper shield's positions and thickness on the rotor losses are studied. Then the variation of temperature rise of the rotor with copper shield thickness is described. Finally, the influences of pole spacer materials on the temperature rise and thermal stress of the rotor are compared and the rules for choosing pole spacer materials are summarized.