In this paper, a new loss minimization control algorithm for inverter-fed permanent-magnet synchronous motors (PMSMs), which allows for the reduction of the power losses of the electric drive without penalty on its dynamic performance, is analyzed, experimentally realized, and validated. In particular, after a brief recounting of two loss minimization control strategies, namely, the "search control" and the "loss-model control," both a new modified dynamic model of the PMSM (which takes into account the iron losses) and an innovative "loss-model" control strategy are presented. Experimental tests on a specific PMSM drive employing the proposed loss minimization algorithm have been performed, aiming to validate the actual implementation. The main results of these tests confirm that the dynamic performance of the drive is maintained, and in small motors enhancement up to 3.5% of the efficiency can be reached in comparison with the PMSM drive equipped with a more traditional control strategy.

This paper presents a low cost, simple, and highly accurate resolver-to-digital converter (RDC) for electrical drive applications based on an integrated software approach, thus allowing a significant reduction of hardware components count with significant improvements in terms of reliability, reduction of fault rate, and susceptibility to electromagnetic interference (EMI). Particular attention has been addressed to cost which is 25% off over conventional RDC. Simulations and experimental tests confirm the high quality of the proposed system.

This paper presents an investigation and a comprehensive analysis on fault operations in a conventional three-phase voltage source inverter. After an introductory section dealing with power converter reliability and fault analysis issues in power electronics, a generalized switching function accounting for both healthy and faulty conditions and an easy and feasible method to embed fault diagnosis and reconfiguration within the control algorithm are introduced. The proposed system has simple and compact implementation. Experimental results operating both at open- and closed-loop current control, obtained using a test bench realized using a dSPACE system and the fault-tolerant inverter prototype demonstrate that the proposed solution is effective and feasible and makes all faults easily managed by the controller itself.

In this paper, a new software tool developed by the authors for ac winding design, optimization, and complete analysis is presented. In particular, this software can be used as a valid aid in design and analysis for a wide variety of motor and generator windings with generic number of phases (including the case of those machines in which some slots are left empty), pole pairs, slot number, and so on. The calculation of winding factors and the evaluation of their harmonic distribution is also accomplished. The software is implemented in the MATLAB programming environment. By means of some examples, covering the most relevant winding types, the capabilities of this software will be shown. In particular, integer and fractional slot, single- and double-layer winding, concentrated windings, imbrication, belt widening, and belt shifting techniques can be treated to reduce particular harmonics in the electromotive force (EMF) or in the magnetomotive force (MMF). Finally, the connections, the winding factor harmonic distribution, the total harmonic distortion (THD) of EMF and spatial distribution of both the MMF, the Görges polygon, and the flux density are shown together with an estimate of the differential leakage and the air-gap flux density spatial distribution. The software presented in this paper is very modular, highly structured, and flexible due to the conspicuous number of operations that it can fulfill. Clearly, for the sake of brevity and clarity, the authors limit to represent the main features of the software, without going into specific details of programming and coding. All the main mathematical relationships that are useful to solve the problem of design and optimization of the windings of rotating machines are hereafter presented.

In modern high power electrical drives, the efficiency of the system is a crucial constraint. Moreover, the efficiency of power converters plays a fundamental role for modern applications requiring also a limited weight, such the electric vehicles and novel more electric aircrafts. The reduction of losses pushes for systems with a DC bus and a high number of DC/AC converters, widespread in the vehicle, not burdened by a too expensive data processing system. The purpose of this work is to concur to reduce losses by proposing an innovative selective harmonic mitigation method based on the identification of the working areas where the reference harmonics present lower amplitudes. In particular, the main objective is to find a new way to calculate the control angles in real-time operation without solving non-linear equations, whose resolution would require expensive controllers. Through a very simple approach, the polynomial equations, which drive the control angles, were detected for a three-phase five-level cascaded H-bridge inverter and implemented in a digital system to real-time operation with a low computational cost. As result, a comparison between simulation and experimental behavior is presented. In the last part of the paper, a real electric machine is driven by considering the appropriate working areas of the inverter and current harmonics are also evaluated.

Winding design methods have been a subject of research for many years of the past century. Many methods have been developed, each one characterized by some advantages and drawbacks. Nowadays, the star of slots is the most widespread design tool for electrical machine windings. In this context, this paper presents a simple and effective procedure to determine the distribution of the slot EMFs over the phases and of the winding configuration in all possible typologies of electrical machines equipped with symmetrical windings. The result of this procedure gives a Winding Distribution Table (WDT), which can be used to define coils and coil groups connections and also to simply implement winding optimizations techniques, such as zone widening, imbrication, etc. Moreover, this procedure can be easily implemented on a computer in order to perform automated winding designs for rotating electrical machines. Several examples are provided in order to validate the proposed procedure.