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This paper explores the use of speed harmonic for accurate and fast maximum-torque-per-ampere (MTPA) control of interior permanent magnet synchronous machines (IPMSMs). A novel MTPA angle calculation approach is proposed, in which the MTPA angle is directly calculated from the phase angle of the speed harmonic that is induced by an injected harmonic current. At first, the relation between the speed harmonic and machine parameters is derived from the IPMSM model, which shows that the phase angle of the induced speed harmonic can be utilized to cancel the machine parameters in existing MTPA equation. Thus, a new MTPA equation is derived, which does not involve machine parameters for MTPA angle calculation. Compared with existing methods, the proposed approach is independent from the machine and drive nonlinearities. Moreover, the MTPA angle is directly calculated from the derived MTPA equation, so the proposed approach is fast and computationally efficient. Thus, the proposed approach is suitable for both on-line applications and building off-line lookup tables of MTPA angles for IPMSMs. The proposed approach is experimentally evaluated on a laboratory IPMSM drive system. [ABSTRACT FROM AUTHOR]

This paper presents a methodology for the design, analysis, and graphical optimization of ironless brushless permanent magnet machines primarily for generator applications. Magnetic flux in this class of electromagnetic machine tends to be 3-D due to the lack of conventional iron structures and the absence of a constrained magnetic flux path. The proposed methodology includes comprehensive geometric, magnetic and electrical dimensioning followed by detailed 3-D finite element (FE) modeling of a base machine for which parameters are determined. These parameters are then graphically optimized within sensible volumetric and electromagnetic constraints to arrive at improved design solutions. This paper considers an ironless machine design to validate the 3-D FE model to optimize power conversion for the case of a low-speed, ironless stator generator. The machine configuration investigated in this paper has concentric arrangement of the rotor and the stator, solenoid-shaped coils, and a simple mechanical design considered for ease of manufacture and maintenance. Using performance and material effectiveness as the overriding optimization criteria, this paper suggests optimal designs configurations featuring two different winding arrangements, i.e., radial and circumferentially mounted. Performance and material effectiveness of the studied ironless stator designs are compared to published ironless machine configurations. [ABSTRACT FROM AUTHOR]