Electric Drive Based on an Open-End Winding Surface PM Synchronous Machine with a Floating Capacitor Bridge

A speed control scheme is presented for a 3-phase surface permanent magnet synchronous machine with an openend stator winding fed by a three-phase inverter and a floating bridge inverter. The latter is used to compensate for the reactive power of the main inverter and to maximize the active power received by the motor, without exceeding the available stator current and DC-link voltage. To reduce the switching losses, the DC-link voltage of the floating inverter bridge varies depending on the operating condition of the motor and the controllability requirements of the system. The experimental results show that a significant improvement in the speed range at constant power is achievable, proportionally to the DC-link voltage of the floating bridge inverter

A simple braking method for six-phase induction motor drives with unidirectional power flow in the base-speed region

Induction motor drives supplied from diode front-end rectifiers are commonly used in industrial applications due to their low cost and reliability. However, the two-quadrant operation of such a topology makes the regenerative braking impossible. Braking resistors can be used to dissipate the braking power and provide enhanced braking capability, but additional hardware is then necessary. Alternatively, the braking power can be dissipated within the inverter/motor by control software reconfiguration. In this scenario, the additional degrees of freedom of multiphase drives can be used to increase the system losses without disturbing the flux and torque production. Experimental results confirm the possibility to enhance the braking capability of six-phase drives with only few changes in the control scheme

Rotor magnet demagnetisation diagnosis in asymmetrical six-phase surface-mounted AC PMSM drives

Multiphase permanent-magnet synchronous machines (PMSMs) are receiving more and more interest in safety-critical modern industries owing to their higher reliability when compared with conventional three-phase PMSMs. Rotor magnets are critical components, which, in case of fault, directly affect the performance of the PMSMs. Thus, monitoring the rotor magnets status is essential to ensure both high level of efficiency and service continuity. The present study focuses on the investigation of a new approach for the detection of rotor magnet demagnetisation in a vector-controlled asymmetrical six-phase surface-mounted AC PMSM. The main contribution of the proposed technique is the assessment of a rotor demagnetisation fault index derived from the fifth and seventh harmonics of the stator voltage space vector evaluated in the α 5–β 5-plane, and already available in the control system platform. The performance of the proposed approach is evaluated using finite element analysis and numerical simulations, both validated by experimental tests

Impact of Star Connection Layouts on the Control of Multiphase Induction Motor Drives Under Open-Phase Fault

This paper presents a post-fault control algorithm that minimizes the stator Joule losses in multiphase induction machines under an open-phase fault and for different star connection layouts. The key novelty is that the algorithm can be applied to any configuration of a multi n-phase machine, independently of the connection of the neutral points. The latter is analytically derived and is based on the space vector representation of the machine model. Also, it is shown that a low number of neutral points helps to reduce the winding losses in case of an open-phase fault but requires additional control regulators and computational efforts. The theory is applied to an asymmetrical quadruple three-phase induction machine, which is configured to represent five different motor layouts. Finally, experimental results are presented to validate the control algorithm. The optimal solution that is given in the paper can be employed for the control of symmetrical or asymmetrical multiphase machines with different star connection layouts and in any open-phase post-fault operation

Preparing Phase 4 of the n_TOF/CERN facility

After CERN's Long Shutdown 2, the n_TOF facility infrastructure was largely upgraded. The biggest change is the installation of a new lead spallation target, the performance of which needs to be carefully examined. During Summer 2021, the facility's two flight paths were characterised in terms of neutron beam energy distribution, profile and resolution. In this work, the characterisation of the facility is described and the first results are given

-1- Generalità e Circuiti Magnetici - rev

Glavni cilj ovog diplomskog rada je usporediti preporuke o vrsti i količini tjelovježbe potrebne za održavanje i unapređenje zdravlja i kvalitete življenja te poboljšanja antropološkog statusa. Usporedit će se preporuke dostupne na internetskim portalima s preporukama temeljnim na stručnoj i znanstvenoj literaturi da bi se dobio uvid u valjanost, ispravnost i pouzdanost informacija na internetu. Koliko su te informacije vjerodostojne i primjenjive u stvarnom životu provjerit će se na primjeru aktivnosti visokog intenziteta kao osnovi svih modernih fitnes programa koji su trenutno popularni, a poznati su pod nazivima CrossFit, Insanity, BootCamp i nekih od aktivnosti umjerenog intenziteta kao što su vježbe u vodi, a isto se u javnosti promoviraju kao korisni za naše zdravlje. Primjerenost takvih programa za održavanje zdravstvenog statusa i kvalitete života te drugih ciljeva kao što je smanjenje viška potkožnog masnog tkiva ili povećanje udjela mišićne mase istražit će se uzimanjem u obzir preporuke legitimnih znanstvenika i znanstvenih ustanova te usporediti ih s preporukama s kojima se možemo susresti na internet portalima. Preporuke, savjeti i metode postizanja željenih ciljeva dostupne na internetu mogu biti štetne za pojedince koji se nikada u svom životu nisu bavili bilo kakvim oblikom tjelovježbe ili žive jako sedentarnim životom, posebice kada je riječ o visoko intenzivnom treningu koji se provodi samostalno i kod kuće te bez stručnog nadzora. Sve vrste tjelesnih aktivnosti, kako visokog tako i umjerenog intenziteta, valja provoditi u za to primjerenim uvjetima i pod stručnima nadzorom da bi se pospješilo zadovoljavanje potrebe za kretanjem i samoaktualizacijom te smanjio rizik od potencijalnog ozljeđivanja i odustajanja od tjelovježbe u cijelosti.The main aim of this thesis is to compare the recommendations on the kind and amount of exercise required for maintenance and improvement of one's physical health and quality of living as well as the improvement of one’s anthropological state. Recommendations available on internet portals will be compared to recommendations based on professional and scientific literature to gain insight into the validity, accuracy and reliability of information available on the internet. The credibility and applicability of that information in real life will be verified on the example of high intensity exercise as a basis of all currently popular modern fitness program, known as CrossFit, Insanity and Boot camp as well as certain medium intensity exercises such as workout in water, that are also publicly promoted as useful for one’s health. The validity of such programs for maintaining one’s health and quality of life as well as other objectives, such as reducing excess body fat or increasing muscle mass, will be investigated by taking into account recommendations of legitimate scientists and scientific institutions and comparing them to recommendations that we encounter on internet portals. Recommendation, advices and methods of achieving desired results accessible on the internet can be harmful for individuals who have never engaged in any physical exercise or live an extremely sedentary life, especially in regards to high intensity exercise performed independently at home without professional supervision. All forms of physical exercise, high intensity as well as medium intensity, should be conducted in appropriate conditions and under professional supervision in order to improve the likelihood of meeting one’s need for mobility and self-actualization as well as reducing the risk of potential injury and giving up on exercise altogether