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Thermal ageing is one of the key factors that result in insulation degradation leading to lower dielectric strength and thereafter occurrence of partial discharge in high voltage machines. However, in low voltage high current machines, the occurrence of partial discharge is minimal and degradation of dielectric strength alone will not cause the breakdown of the insulation. This paper hypothesizes...
The use of inverter-driven motors in aircraft has been steadily increasing to replace hydraulic and pneumatic systems. Accurate knowledge of the motor parameters including the winding stray capacitance is required to construct a wider motor/drive systems model to investigate electromagnetic compatibility (EMC) issues and also to correctly size the common mode EMC filter components. In this paper,...
This paper presents the design and optimization of an airliner fan motor to adapt it to a 540V HVDC network, starting with an existing BLDC motor. The motor reliability must be kept despite the increased constraint on the insulation due to higher voltage. A small tooth separating the slot in two is introduced, along with a fractional slot concentrated winding, allowing the phases to be kept separate...
This paper focuses on aging and breakdown of insulation systems of rotating machines (Type I insulation). Specifically, it deals with the partial discharge (PD) phenomenology, comparing the PD behavior of phase to ground and turn insulation under sinusoidal and PWM-type voltage. Two-level and multilevel inverter design, with different rise times of the repetitive voltage impulses generated by the...
Forced by the high requirements on modern variable speed controlled drives, power electronics are used to achieve the specific requirements on accuracy and dynamics. These properties are realized by fast switching converters, which result in voltages and currents with high slew rates. As a consequence, these rise times or slew rates lead to high frequency phenomena throughout the electrical drive...
This paper presents a fast and accurate 2-D spectral element model for analyzing electric field distributions in linear synchronous motors. The electric field distribution is derived using the electric scalar potential for static cases. The spatial potential and electric field distributions obtained by the spectral element method are validated by finite element analysis. Protrusions, voids and rounded...
Advanced high speed permanent magnet synchronous machines (PMSM) have been the subject of recent research for electrified transportation. Specific power of electric machines must increase in order to make hybrid-electric passenger aircraft feasible. Raising operating frequency improves specific power and requires robust windings. This paper will present electrical loss, dielectric, thermal, and mechanical...
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