UC San Diego
Novel High Power Density Turn-Less Motor Concept
- Author(s): Liu, Christopher Kirby
- Advisor(s): Yu, Paul K
- et al.
Recent developments in power transistor technologies, particularly with low voltage and high current densities have enabled a redesign of conventional motor technologies. In typical electromechanical devices, multiple turns are used to increase the generated magnetic field of the coil. For motor applications, this results in higher operating voltages in exchange for lower current requirements, as well as larger leakage inductance due to the added volume outside the motor’s stator for the return paths of copper. Additionally, the manufacturing of these motors either require complex machinery or costly labor-intensive methods to wind the motors. Alternatively, the Polarix motor-inverter unit relies on cutting-edge semiconductor technologies to engineer a novel turn-less motor topology. The motor takes advantage of a fortuitous match between current and voltage requirements in a single winding of a motor, to the current and voltage capabilities of high performance transistors. A single motor unit is comprised of 3 conductors (formed in the stator) shorted in a Y configuration and driven by a three-phase inverter. In this topology, we show that a higher power density can be achieved with low total inductance and simplified manufacturing. This thesis serves to demonstrate the viability of this technology on a circular motor – additionally the design, construction and performance is discussed in depth.