Papers on Electric Machines by Paolo Bolognesi
16th International Conference on Electrical Machines - ICEM 2004, Sep 2004
The lumped-parameters modeling of electromechanical devices in terms of equivalent circuits and r... more The lumped-parameters modeling of electromechanical devices in terms of equivalent circuits and rigid bodies is widely in use by long time. In fact, it permits to draw important theoretical conclusions and to obtain handy analytical results useful for dynamic analysis. Nevertheless, this approach is often presented in reduced forms, e.g., assuming a single mechanical degree-of-freedom, magnetic linearity, 3-phase symmetrical windings, etc. This paper proposes a generalized treatment suppressing several of such hypotheses, leveraging on matrix notation and lagrangian notation for mechanical aspects to provide a powerful conceptual tool for the analysis of a wide class of devices.
18th International Conference on Electrical Machines - ICEM 2008, Sep 2008
The theoretical derivation of equivalent circuits by analytically modeling the internal electroma... more The theoretical derivation of equivalent circuits by analytically modeling the internal electromagnetic phenomena constitutes a classical approach for analyzing electric machines. Anyway, textbooks often tend to address it adopting a limited approach focused on specific common cases, thus introducing not strictly necessary hypotheses that turn into a reduced insight of the matter. On the other hand, papers focused on the derivation of analytical expressions of fields often adopt a much detailed approach resulting unwisely complex for circuital modeling. This paper proposes an intermediate circuit-oriented analysis that is more general and rigorous than usual while keeping a reasonable level of complexity of the treatment, thus resulting also suited for educational purposes at graduate level and above.
17th International Conference on Electrical Machines - ICEM 2006, Sep 2006
The circuital approach permits to obtain handy models of electric machines, representing the main... more The circuital approach permits to obtain handy models of electric machines, representing the main aspects of their external behavior avoiding the complexity of a field-based analysis. In typical cases, a further simplification of the model may be achieved by applying classical variables transformations. Anyway, these were derived and used referring to some common machine typologies. Basing on a generalized analysis previously developed for a broad class of electromechanical devices, this paper investigates the application of generic uniform invertible parametric pseudo-linear orthonormal transformations, which
are shown featuring interesting general properties that constitute a generalization of well known classical results.
16th International Conference on Electrical Machines - ICEM 2004, Sep 2004
Nowadays, advanced applications of motion control often require a coordinated management of sever... more Nowadays, advanced applications of motion control often require a coordinated management of several mechanical degrees-of-freedom (DoF). This is conventionally achieved by using suitable mechanical devices and a separate actuator per each DoF. Electric actuators able to directly manage multiple DoF may provide appreciable benefits in terms of performances, volume, weight and cost. This paper aims to provide an overview of several configurations of multi-DoF electromechanical actuators considered in the recent technical literature and presently under study.
International Symposium on Industrial Electronics - ISIE 2002, 2002
In apparatuses requiring articulated movements involving multiple freedom degrees, usually each o... more In apparatuses requiring articulated movements involving multiple freedom degrees, usually each one is managed by means of a conventional actuator charged to control the corresponding elementary motion, and the required comprehensive motion is obtained with the aid of suitable mechanisms. Nevertheless, weight, space and cost savings, besides structural simplifications, could be achieved by employing actuators able to simultaneously manage more freedom degrees. This paper proposes a novel
rotary-linear 4-phase permanent magnets brushless motor. The machine structure and its basic principles are first described, obtaining then an approximated analytical
model by means of a simplified electromagnetic analysis based on the equivalent magnetic circuit approach. The machine regulation is then examined, demonstrating the ideal possibility to achieve a fully decoupled control of the electromagnetic force and torque, joined to the suppression of the potentially correlated ripple phenomena, by adopting a suitable yet simple supply logic. Several theoretical waveforms are finally reported.
20th International Symposium on Power Electronics, Electrical Drives, Automation and Motion - SPEEDAM 2010, 2010
The combination of a rotary and linear motion along the same axis is used in several applications... more The combination of a rotary and linear motion along the same axis is used in several applications, including tooling machines, robotics, automation etc. It may be also used to conveniently manage pairs of basic functions of active wheels in electric and hybrid vehicles. In such cases, rotary-linear machines may represent an interesting alternative to the usual employ of a separated actuator per each basic motion. Anyway, such machines often rely on a structure that is either not suited to be conveniently realized using common materials and manufacturing techniques, or exhibits a complex behavior not permitting an effective decoupled control of force and torque. This paper presents some results concerning the structure, theoretical modeling, FEM analysis, magnetic circuit modeling and drive control for an isotropic brushless machine recently proposed.
19th International Conference on Electrical Machines - ICEM 2010, 2010
In several applications, ranging from industrial robotics to advanced automotive, a combination o... more In several applications, ranging from industrial robotics to advanced automotive, a combination of rotary and linear motions along the same axis is ultimately required.
Rotary-linear motors, providing both torque and force, may permit to fulfill the related requirements more effectively than conventional solutions using 2 distinct normal actuators. This paper presents the FEM modeling and analysis of a novel rotary-linear permanent magnets synchronous machine, whose structure, analytical modeling and control are presented in companion papers. Such machine was purposely conceived to be manufactured using common affordable technologies or even by assembling standard parts. A 3-D parametric model purposely developed to permit a detailed analysis of the machine operation is described. Several simulation results concerning various operative conditions are reported and commented, confirming the substantial validity of the basic idea and highlighting the secondary effects due to non-ideal aspects of machine behavior.
Symposium on Power Electronics, Electrical Drives, Automation & Motion - SPEEDAM 2006, 2006
In the framework of a recent Italian National Research Project focused on drive-by-wire systems f... more In the framework of a recent Italian National Research Project focused on drive-by-wire systems for industrial vehicles, a high-torque electric actuator was searched complying with stringent requirements in terms of specific performances, cost and dependability. This paper describes the considerations and guidelines that led to the development of an innovative electromagnetic structure for a double-anisotropic reluctance machine, illustrating its features and providing an overview of the theoretical, numerical and experimental results achieved.
11th European Conference on Power Electronics and Applications - EPE 2005, 2005
This paper presents a first overview of an unconventional switched-reluctance rotating machine co... more This paper presents a first overview of an unconventional switched-reluctance rotating machine conceived to provide high specific torque in low-speed applications by leveraging on the magnetic gearing effect while featuring a simple, modular, highly symmetrical structure that should permit to limit manufacturing costs. After recalling the main proposals found in the literature for similar targets, the first application considered for the machine is briefly described. The proposed structure is then introduced and briefly analyzed, highlighting the main features and issues related to manufacturing, performance and control. A few results coming from 3-D FEM analysis of the machine are finally reported and briefly commented.
4th International Conference on Power Electronics, Machines and Drives - PEMD 2008, Apr 2, 2008
Doubly-salient variable reluctance machines present several interesting aspects, such as winding ... more Doubly-salient variable reluctance machines present several interesting aspects, such as winding simplicity, no need of expensive permanent magnets, robustness etc. An innovative machine of such type, featuring a simple modular, multistack, axial-flux, homopolar magnetic structure, was recently proposed. This paper provides considerations about the features, design and manufacturing options for such machine, finally describing the first prototype realized.
Micro-turbine based high speed gensets exhibit several interesting features such as compactness a... more Micro-turbine based high speed gensets exhibit several interesting features such as compactness and light weight, low maintenance, fuel flexibility, relatively low emissions,
durability, high reliability etc. They represent an interesting solution in the distributed generation perspective, especially when employed as mid-low power co-generation units possibly exploiting byproducts of farming activities. This paper presents the preliminary design and FEM/circuital analysis of a high speed permanent magnets synchronous brushless machine useable as generator in such units. Results concerning different operative conditions and current waveforms are reported and commented, considering the opportunity to employ a controlled AC/DC converter in spite of the usual diodes rectifier bridge.
20th International Symposium on Power Electronics, Electrical Drives, Automation and Motion - SPEEDAM 2010, 2010
Permanent magnets synchronous machines are nowadays widely employed. In case of symmetrical const... more Permanent magnets synchronous machines are nowadays widely employed. In case of symmetrical construction, aligned mounting of the rotor and balanced supply, the distributed surface magnetic actions on the rotor feature a null resultant. Anyway, in case of defective assembly or when bearings exhibit a reduced or variable stiffness, the eccentricity of rotor determines a resultant force depending on angular position and currents. This paper investigates such phenomenon for a surface-magnets machine, using FEM analysis to permit keeping into account saturation. Simulation results are reported and commented, highlighting that such force may be affected from stator currents in a counter-intuitive way when magnetic saturation of the core becomes appreciable: in such event, the worst-case scenario required for design purposes must be carefully singled out.
19th International Conference on Electrical Machines - ICEM 2010, 2010
Permanent magnets synchronous machines are used in many different applications. While the popular... more Permanent magnets synchronous machines are used in many different applications. While the popular surface magnets isotropic variant is the simplest to manufacture and control, its relatively low airgap flux density limits the specific performances that are further reduced when a bandage is used to retain magnets. The different buried magnets variants may be tailored to improve the most relevant aspects, yet resulting more complex and expensive with a less robust rotor core. Inset magnets machines may constitute an interesting intermediate solution. In particular, the consequent pole variant features a simple and robust structure with some design flexibility. This paper investigates the opportunity to design consequent-pole machines featuring rotors with different pole and magnet angular width, aiming to improve the specific performances by better exploiting the potential of silicon steel laminations.
16th International Conference on Electrical Machines - ICEM 2004, Sep 2004
Classical Potier model is widely used to predict the behavior of isotropic synchronous machines i... more Classical Potier model is widely used to predict the behavior of isotropic synchronous machines in steady state conditions keeping into account the main effects of core saturation. Its parameters are usually determined using a popular traditional procedure, but the obtained model proved to appreciably lack accuracy in some machines at high loads. It also requires a short-circuit test, rather unpractical in large
machines. This paper proposes a generalization of such procedure, retaining its basic simplicity while allowing a much wider flexibility in the selection of test points. In fact, it uses 2 correlated null-power-factor tests, possibly carried out at the same voltage even with machine connected to the grid, avoiding the short-circuit test and permitting a more focused parametrization for operating range around the rated point.
18th International Conference on Electrical Machines - ICEM 2008, 2008
In some niche applications, e.g. emergency pumps operating in case of fire, a high reliability an... more In some niche applications, e.g. emergency pumps operating in case of fire, a high reliability and a constant speed operation capability are basically required. This paper deals with the use of hybrid excitation in DC motors to permit a highly reliable operation under adjustable field supply and unregulated armature supply, e.g. provided by an emergency accumulator. In fact, the field winding permits to retain a possibly adequate speed regulation capability, while the magnets ultimately allow an
uncontrolled operation even in case of full failure of the excitation system. The paper presents a preliminary design and its validation and optimization by means of FEM analysis.
35th Annual Conference of Industrial Electronics Society - IECON 2009, Nov 2009
Ram air turbines, deployed in the external airflow during flight, are used as emergency power sou... more Ram air turbines, deployed in the external airflow during flight, are used as emergency power sources to feed the vital apparatuses required for governing aircrafts in case of
failure of main supply systems. Such turbines mostly drive electric generators usually connected to a DC bus supported by emergency batteries, which supplies the vital avionic systems. Such generators must then feature high dependability, adequate
regulation capability and good overall efficiency. This paper investigates the employ for such purpose of hybrid-excitation DC machines, which may achieve a high reliability thanks to the inherent internal redundancies and to the limited use of electronic components. Referring to a mid-power case-study, a preliminary design and FEM-circuital models purposely developed for validation and design refinement are described, finally reporting and commenting significant simulation results.
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, Jan 1, 2010
The purpose of this paper is to investigate the use of hybrid-excitation solutions, using
contem... more The purpose of this paper is to investigate the use of hybrid-excitation solutions, using
contemporaneously permanent magnets and field coils, for DC machines intended to operate as the core of high-reliability drives in critical applications supplied by batteries (e.g. fire-extinguishing pumps, smoke blowers, etc.) where a roughly constant speed is required and a minimal use of electronic devices is prescribed to improve overall dependability. A high-reliability hybrid-excitation DC motor, initially designed basing on theoretical considerations, is then analyzed using purposely developed 2D and 3D finite element method (FEM) electromagnetic models under static, dynamic, healthy, and faulty conditions. The simulation results confirm that properly designed drives employing
hybrid-excitation DC motors may constitute an effective solution for applications requiring a very high reliability under DC supply with limited speed regulation capability.
Papers on Power Electronics by Paolo Bolognesi
IEEE-PELS 39th Power Electronics Specialists Conference - PESC 2008, Jun 15, 2008
Typically, electric energy is available from mains via a.c. feeders, which are usually 1-phase fo... more Typically, electric energy is available from mains via a.c. feeders, which are usually 1-phase for power levels below several kVA due to convenience reasons. Anyway, the
availability of a 3-phase supply might benefit also such class of loads, e.g. permitting to directly supply better quality induction motors. This paper proposes a converter able to
generate an almost symmetrical 3-phase supply from a 1-phase feeder, featuring low complexity, full reversibility, a quasi-sinusoidal output and a pseudo-resistive or quasi sinusoidal in-phase input. After a circuital theoretical analysis, considerations about the possible control strategies are developed and a simulation model purposely get ready is
described. Finally, simulation results illustrating the proposed solution are reported and commented.
IEEE-IES 35th Annual Conference of Industrial Electronics Society - IECON 2009, 2009
Utilities often provide power supply via standard 1- phase low-voltage AC feeders, at least in th... more Utilities often provide power supply via standard 1- phase low-voltage AC feeders, at least in the range up to several kVA. In rural areas and developing countries, even MV 1-phase
distribution grids are sometimes used. Nevertheless, 3-phase load appliances are often preferable: in such case, apparatuses able to effectively convert 1-phase feeders into standard 3-phase supplies are then required. After a brief recall of the few specific solutions available in the literature, this paper focuses on the 3-and 4- wires variants of a recently proposed converter aimed to achieve low complexity, full reversibility and high power quality. Its power structure and control strategies are described, recalling also analytical and simulation models. A theoretical steady state analysis, design considerations and several simulation results are reported and commented, confirming the good performances achieved also under unfavorable conditions.
18th International Conference on Electrical Machines - ICEM 2008, 2008
Due to historical reasons, the most diffused solution for electric energy transmission is via fix... more Due to historical reasons, the most diffused solution for electric energy transmission is via fixed voltage and frequency a.c. grids. A 3-phase symmetric supply results typically preferable; anyway, due to practical reasons 1-phase feeders are mostly used for low-power final distribution up to several kVA. This paper deals with a low-complexity converter that was recently proposed to provide a high power quality reversible interface between 1-phase supply and 3-phase loads. Some improvements in the control system are presented, reporting and commenting simulation results showing better performances under nonlinear, unbalanced and variable loads.
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Papers on Electric Machines by Paolo Bolognesi
are shown featuring interesting general properties that constitute a generalization of well known classical results.
rotary-linear 4-phase permanent magnets brushless motor. The machine structure and its basic principles are first described, obtaining then an approximated analytical
model by means of a simplified electromagnetic analysis based on the equivalent magnetic circuit approach. The machine regulation is then examined, demonstrating the ideal possibility to achieve a fully decoupled control of the electromagnetic force and torque, joined to the suppression of the potentially correlated ripple phenomena, by adopting a suitable yet simple supply logic. Several theoretical waveforms are finally reported.
Rotary-linear motors, providing both torque and force, may permit to fulfill the related requirements more effectively than conventional solutions using 2 distinct normal actuators. This paper presents the FEM modeling and analysis of a novel rotary-linear permanent magnets synchronous machine, whose structure, analytical modeling and control are presented in companion papers. Such machine was purposely conceived to be manufactured using common affordable technologies or even by assembling standard parts. A 3-D parametric model purposely developed to permit a detailed analysis of the machine operation is described. Several simulation results concerning various operative conditions are reported and commented, confirming the substantial validity of the basic idea and highlighting the secondary effects due to non-ideal aspects of machine behavior.
durability, high reliability etc. They represent an interesting solution in the distributed generation perspective, especially when employed as mid-low power co-generation units possibly exploiting byproducts of farming activities. This paper presents the preliminary design and FEM/circuital analysis of a high speed permanent magnets synchronous brushless machine useable as generator in such units. Results concerning different operative conditions and current waveforms are reported and commented, considering the opportunity to employ a controlled AC/DC converter in spite of the usual diodes rectifier bridge.
machines. This paper proposes a generalization of such procedure, retaining its basic simplicity while allowing a much wider flexibility in the selection of test points. In fact, it uses 2 correlated null-power-factor tests, possibly carried out at the same voltage even with machine connected to the grid, avoiding the short-circuit test and permitting a more focused parametrization for operating range around the rated point.
uncontrolled operation even in case of full failure of the excitation system. The paper presents a preliminary design and its validation and optimization by means of FEM analysis.
failure of main supply systems. Such turbines mostly drive electric generators usually connected to a DC bus supported by emergency batteries, which supplies the vital avionic systems. Such generators must then feature high dependability, adequate
regulation capability and good overall efficiency. This paper investigates the employ for such purpose of hybrid-excitation DC machines, which may achieve a high reliability thanks to the inherent internal redundancies and to the limited use of electronic components. Referring to a mid-power case-study, a preliminary design and FEM-circuital models purposely developed for validation and design refinement are described, finally reporting and commenting significant simulation results.
contemporaneously permanent magnets and field coils, for DC machines intended to operate as the core of high-reliability drives in critical applications supplied by batteries (e.g. fire-extinguishing pumps, smoke blowers, etc.) where a roughly constant speed is required and a minimal use of electronic devices is prescribed to improve overall dependability. A high-reliability hybrid-excitation DC motor, initially designed basing on theoretical considerations, is then analyzed using purposely developed 2D and 3D finite element method (FEM) electromagnetic models under static, dynamic, healthy, and faulty conditions. The simulation results confirm that properly designed drives employing
hybrid-excitation DC motors may constitute an effective solution for applications requiring a very high reliability under DC supply with limited speed regulation capability.
Papers on Power Electronics by Paolo Bolognesi
availability of a 3-phase supply might benefit also such class of loads, e.g. permitting to directly supply better quality induction motors. This paper proposes a converter able to
generate an almost symmetrical 3-phase supply from a 1-phase feeder, featuring low complexity, full reversibility, a quasi-sinusoidal output and a pseudo-resistive or quasi sinusoidal in-phase input. After a circuital theoretical analysis, considerations about the possible control strategies are developed and a simulation model purposely get ready is
described. Finally, simulation results illustrating the proposed solution are reported and commented.
distribution grids are sometimes used. Nevertheless, 3-phase load appliances are often preferable: in such case, apparatuses able to effectively convert 1-phase feeders into standard 3-phase supplies are then required. After a brief recall of the few specific solutions available in the literature, this paper focuses on the 3-and 4- wires variants of a recently proposed converter aimed to achieve low complexity, full reversibility and high power quality. Its power structure and control strategies are described, recalling also analytical and simulation models. A theoretical steady state analysis, design considerations and several simulation results are reported and commented, confirming the good performances achieved also under unfavorable conditions.
are shown featuring interesting general properties that constitute a generalization of well known classical results.
rotary-linear 4-phase permanent magnets brushless motor. The machine structure and its basic principles are first described, obtaining then an approximated analytical
model by means of a simplified electromagnetic analysis based on the equivalent magnetic circuit approach. The machine regulation is then examined, demonstrating the ideal possibility to achieve a fully decoupled control of the electromagnetic force and torque, joined to the suppression of the potentially correlated ripple phenomena, by adopting a suitable yet simple supply logic. Several theoretical waveforms are finally reported.
Rotary-linear motors, providing both torque and force, may permit to fulfill the related requirements more effectively than conventional solutions using 2 distinct normal actuators. This paper presents the FEM modeling and analysis of a novel rotary-linear permanent magnets synchronous machine, whose structure, analytical modeling and control are presented in companion papers. Such machine was purposely conceived to be manufactured using common affordable technologies or even by assembling standard parts. A 3-D parametric model purposely developed to permit a detailed analysis of the machine operation is described. Several simulation results concerning various operative conditions are reported and commented, confirming the substantial validity of the basic idea and highlighting the secondary effects due to non-ideal aspects of machine behavior.
durability, high reliability etc. They represent an interesting solution in the distributed generation perspective, especially when employed as mid-low power co-generation units possibly exploiting byproducts of farming activities. This paper presents the preliminary design and FEM/circuital analysis of a high speed permanent magnets synchronous brushless machine useable as generator in such units. Results concerning different operative conditions and current waveforms are reported and commented, considering the opportunity to employ a controlled AC/DC converter in spite of the usual diodes rectifier bridge.
machines. This paper proposes a generalization of such procedure, retaining its basic simplicity while allowing a much wider flexibility in the selection of test points. In fact, it uses 2 correlated null-power-factor tests, possibly carried out at the same voltage even with machine connected to the grid, avoiding the short-circuit test and permitting a more focused parametrization for operating range around the rated point.
uncontrolled operation even in case of full failure of the excitation system. The paper presents a preliminary design and its validation and optimization by means of FEM analysis.
failure of main supply systems. Such turbines mostly drive electric generators usually connected to a DC bus supported by emergency batteries, which supplies the vital avionic systems. Such generators must then feature high dependability, adequate
regulation capability and good overall efficiency. This paper investigates the employ for such purpose of hybrid-excitation DC machines, which may achieve a high reliability thanks to the inherent internal redundancies and to the limited use of electronic components. Referring to a mid-power case-study, a preliminary design and FEM-circuital models purposely developed for validation and design refinement are described, finally reporting and commenting significant simulation results.
contemporaneously permanent magnets and field coils, for DC machines intended to operate as the core of high-reliability drives in critical applications supplied by batteries (e.g. fire-extinguishing pumps, smoke blowers, etc.) where a roughly constant speed is required and a minimal use of electronic devices is prescribed to improve overall dependability. A high-reliability hybrid-excitation DC motor, initially designed basing on theoretical considerations, is then analyzed using purposely developed 2D and 3D finite element method (FEM) electromagnetic models under static, dynamic, healthy, and faulty conditions. The simulation results confirm that properly designed drives employing
hybrid-excitation DC motors may constitute an effective solution for applications requiring a very high reliability under DC supply with limited speed regulation capability.
availability of a 3-phase supply might benefit also such class of loads, e.g. permitting to directly supply better quality induction motors. This paper proposes a converter able to
generate an almost symmetrical 3-phase supply from a 1-phase feeder, featuring low complexity, full reversibility, a quasi-sinusoidal output and a pseudo-resistive or quasi sinusoidal in-phase input. After a circuital theoretical analysis, considerations about the possible control strategies are developed and a simulation model purposely get ready is
described. Finally, simulation results illustrating the proposed solution are reported and commented.
distribution grids are sometimes used. Nevertheless, 3-phase load appliances are often preferable: in such case, apparatuses able to effectively convert 1-phase feeders into standard 3-phase supplies are then required. After a brief recall of the few specific solutions available in the literature, this paper focuses on the 3-and 4- wires variants of a recently proposed converter aimed to achieve low complexity, full reversibility and high power quality. Its power structure and control strategies are described, recalling also analytical and simulation models. A theoretical steady state analysis, design considerations and several simulation results are reported and commented, confirming the good performances achieved also under unfavorable conditions.
cost, complexity etc. Different combinations of functions are examined and the main types of rotary-linear machines found in the literature are briefly recalled and commented, finally focusing on a brushless isotropic rotary-linear machine.