Harmonic reduction methods for electrical generation: a review

This paper provides a comprehensive literature review of techniques for harmonic related power quality improvement of electrical generation systems. An increasing interest in these aspects is due to the ever more stringent power quality requirements, deriving from new grid codes and compliancy standards, aimed at limiting waveform harmonic distortion at all points of the distribution network. Although a wealth of literature is available for such techniques, it has never been compiled into a handbook incorporating all the solutions aimed at both electrical machine and power systems engineers

On the Modeling, Analysis and Development of PMSM: For Traction and Charging Application

Permanent magnet synchronous machines (PMSMs) are widely implemented commercially available traction motors owing to their high torque production capability and wide operating speed range. However, to achieve significant electric vehicle (EV) global market infiltration in the coming years, the technological gaps in the technical targets of the traction motor must be addressed towards further improvement of driving range per charge of the vehicle and reduced motor weight and cost. Thus, this thesis focuses on the design and development of a novel high speed traction PMSM with improved torque density, maximized efficiency, reduced torque ripple and increased driving range suitable for both traction and integrated charging applications. First, the required performance targets are determined using a drive cycle based vehicle dynamic model, existing literature and roadmaps for future EVs. An unconventional fractional–slot distributed winding configuration with a coil pitch of 2 is selected for analysis due to their short end–winding length, reduced winding losses and improved torque density. For the chosen baseline topology, a non–dominated sorting genetic algorithm based selection of optimal odd slot numbers is performed for higher torque production and reduced torque ripple. Further, for the selected odd slot–pole combination, a novel star–delta winding configuration is modeled and analyzed using winding function theory for higher torque density, reduced spatial harmonics, reduced torque ripple and machine losses. Thereafter, to analyze the motor performance with control and making critical decisions on inter–dependent design parameter variations for machine optimization, a parametric design approach using a novel coupled magnetic equivalent circuit model and thermal model incorporating current harmonics for fractional–slot wound PMSMs was developed and verified. The developed magnetic circuit model incorporates all machine non–linearities including effects of temperature and induced inverter harmonics as well as the space harmonics in the winding inductances of a fractional–slot winding configuration. Using the proposed model with a pareto ant colony optimization algorithm, an optimal rotor design is obtained to reduce the magnet utilization and obtain maximized torque density and extended operating range. Further, the developed machine structure is also analyzed and verified for integrated charging operation where the machine’s winding inductances are used as line inductors for charging the battery thereby eliminating the requirement of an on–board charger in the powertrain and hence resulting in reduced weight, cost and extended driving range. Finally, a scaled–down prototype of the proposed PMSM is developed and validated with experimental results in terms of machine inductances, torque ripple, torque–power–speed curves and efficiency maps over the operating speed range. Subsequently, understanding the capabilities and challenges of the developed scaled–down prototype, a full–scale design with commercial traction level ratings, will be developed and analyzed using finite element analysis. Further recommendations for design improvement, future work and analysis will also be summarized towards the end of the dissertation

A Study of the Degradation of Electronic Speed Controllers for Brushless DC Motors

Brushless DC motors are frequently used in electric aircraft and other direct drive applications. As these motors are notactually direct current machines but synchronous alternating current machines; they are electronically commutated by a power inverter. The power inverter for brushless DC motors typically used in small scale UAVs is a semiconductor base delectronic commutator that is external to the motor and is referred to as an electronic speed control (ESC). This paper examines the performance changes of a UAV electric propulsion system resulting from ESC degradation. ESC performance is evaluated in simulation and on a new developed test bed featuring propulsion components from a reference UAV. An increase in the rise fall times of the switched voltages is expected to cause timing issues at high motor speeds. This study paves the way for further development of diagnostic and prognostic methods for inverter circuits which are part of the overall electric UAV system

Design and Application of Electrical Machines

Electrical machines are one of the most important components of the industrial world. They are at the heart of the new industrial revolution, brought forth by the development of electromobility and renewable energy systems. Electric motors must meet the most stringent requirements of reliability, availability, and high efficiency in order, among other things, to match the useful lifetime of power electronics in complex system applications and compete in the market under ever-increasing pressure to deliver the highest performance criteria. Today, thanks to the application of highly efficient numerical algorithms running on high-performance computers, it is possible to design electric machines and very complex drive systems faster and at a lower cost. At the same time, progress in the field of material science and technology enables the development of increasingly complex motor designs and topologies. The purpose of this Special Issue is to contribute to this development of electric machines. The publication of this collection of scientific articles, dedicated to the topic of electric machine design and application, contributes to the dissemination of the above information among professionals dealing with electrical machines

Field Weakening Control of Interior Permanent Magnet Synchronous Motor Employing Model Order Reduction

Various control strategies have been adopted for the field weakening control of the interior permanent magnet synchronous motors. Most of these either use the magnetic model parameters or utilize the approaches like the look up tables to minimize the effects of parametric sensitivity. The variation of the inductance values due to the magnetic saturation or the cross-coupling and fluctuation in the stator resistance and the permanent magnet flux due to the temperature difference can significantly affect the control performance especially at high speeds. In this thesis, the field weakening algorithm has been proposed that employs one of the model order reduction technique, i.e. orthogonal interpolation method. This technique obtained from reducing the order of the finite element model of the machine takes the stator current components as input and outputs the corresponding flux linkage components. At first, the control design was implemented utilizing the reduction technique that contained the motor parameters to test the validity of the orthogonal interpolation method in the field weakening operation. Thereupon, the technique was designed operating independent of any machine parameter that put into place the orthogonal interpolation method and its inversion for the references calculation. The simulink feature, ‘algebraic constraint’, was used in combination with the reduction technique to produce the required current components. The control techniques were implemented in the field oriented control scheme. The methods were at first tested through simulations in the MATLAB/Simulink environment and then the experiments were performed in the dSPACE laboratory for validity of the results. The results provided in the end confirm the feasibility of the approach used. The motor operates well in the field aweakening region and can operate in the wide speed range. The results also confirm that the approach operating independent of the machine parameters exhibit better control performance

Modelling, dynamics and control of a permanent magnet generator for wind power applications.

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State-of-art on permanent magnet brushless DC motor drives

Permanent magnet brushless DC (PMBLDC) motors are the latest choice of researchers due to their high efficiency, silent operation, compact size, high reliability and low maintenance requirements. These motors are preferred for numerous applications; however, most of them require sensorless control of these motors. The operation of PMBLDC motors requires rotor-position sensing for controlling the winding currents. The sensorless control would need estimation of rotor position from the voltage and current signals, which are easy to be sensed. This paper presents a state of art on PMBLDC motor drives with emphasis on sensorless control of these motors