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A new stationary-frame AC current control strategy that can eliminate steady-state errors is discussed and applied to the control of transverse flux permanent-magnet machine (TFPM). Based on the principle of modulation and demodulation, this AC controller can achieve the same frequency response characteristic as the equivalent DC controller. Validity of the TFPM control system using this current control strategy is confirmed with simulation results.

A novel embedded-type permanent magnetic motor for hybrid motorcycle, which employs asymmetric design of eccentric air-gap, is proposed in the paper. This special design of air-gap well conforms to the mono-directional operation characteristic of motorcycle and effectively suppresses the distortion of air-gap magnetic field caused by armature reaction. Hence the torque ripple is reduced. A drive system consisting of the newly-designed Nd-Fe-B permanent magnet synchronous motor and parallel-MOSFET three-phase inverter for hybrid motorcycle propulsion is established. Wide-range speed operation is realized through a simple and novel control strategy. Computer simulation is described and experimental results given to verify the practicality of the proposed motor design and control strategy.

The geometrical feature of the skewed rotor slots in induction motors makes the 2-dimensional (2-D) finite element method (FEM) not directly applicable. Based on the multi-slice model in this paper, a time stepping 2-D eddy-current FEM is described to study the steady-state operation and the starting process of induction machines with skewed rotor slots. The fields of the multi-slices are solved in parallel, and thus the effects of skewed slots and eddy-current can be taken into account directly. The basic formulas for the multi-slice model are derived. Special technique to reduce computation time in solving the coupled system equations is also described. The results obtained by using the program developed have very good correlation with the test data.

The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.