A super high speed PM motor drive system by a quasi-current source inverter

FEM modeling of rotor losses in PM motors

“…These eddy currents cause power loss. In design of high-speed PM machines, it is important to know this loss because it heats the rotor which lower the PM operating point and causes pole demagnetization in sintered rare-earth magnets [4].…”

BLDC-SPM motor drive with DC-DC Converter in the DC link: Hall sensor versus sensorless speed control

“…Another approach on BLDC control is to separate speed control and inverter commutation [10][11][12][13], especially in the high speed area. This is called Pulse Amplitude Modulation (PAM), when the inverter is operated with the squarewave of 120° conduction and the speed control is achieved by regulating the DC link input voltage of the inverter [10].…”

“…This is called Pulse Amplitude Modulation (PAM), when the inverter is operated with the squarewave of 120° conduction and the speed control is achieved by regulating the DC link input voltage of the inverter [10]. An efficiency comparison between PWM control and PAM control for refrigerator applications was realized in [11] and the idea of a quasi-current source inverter was presented in [12]. The results were near unit power factor operation, thus improving the system overall efficiency, reducing the dc current ripples and reducing the size of the electrolytic dc filter capacitor.…”

“…Further improvements can be brought by using a film capacitor in the DC link instead of the classic electrolytic capacitor [12][13].…”

Multilevel DC link inverter for brushless permanent magnet motors with very low inductance

“…In [5], the air gap is intentionally made large to reduce the flux harmonics caused by stator slots and thus the resultant iron loss in the stator is significantly decreased for super-high speed PM motors. Recent design techniques on high power PM motors (several tens of kWs) for EV/HEV applications such as the use of ironless stator structure have reduced the inductance even further below 100 µH [6].…”