Oprea Claudiu Alexandru
@utcluj.ro
Departamentul de Mașini și Acționări Electrice
Universitatea Tehnica din Cluj-Napoca
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Şerban Paula, Sebastian Ursache, Claudiu Oprea, Gabriel Chindriș, Mircea Ruba, Răzvan Ințe, Ankidim Zinveli, and Claudia Marțiș
IEEE
The present paper introduces a new concept in the field of vehicle electrification, referring not to a cargo or passenger one but to a funicular. The latter’s operation is normally based on an internal combustion diesel engine. In order to align such an application with the current trends in field of electrification, a project was developed to develop a hybrid solution. The requirements were based on the philosophy that during its operation, the funicular can recover a large quantity of energy during log’s downhill, as the system actually must operate as brake. Studies were engaged when decisioning on the chemistry, Li ion or Lead Acid. The latter one handshake well with operating cycles of a funicular as well as low temperature exposure in forest has less impact on the battery performances. Even more, safety-wise, the Lead Acid cells are not susceptible for fire in case of faults, that is mandatory regulation in forest exploitations. To design and study this system, a complex simulation environment had to be developed, mixing Simcenter Amesim software (for the mechanics) with MATLAB Simulink (for the batteries). Nevertheless, precise battery parameters identification and modelling required processes that are detailed in the paper.
Raul Nemes, Mircea Ruba, Raluca Raia, Claudia Martis, and Claudiu Oprea
Institute of Electrical and Electronics Engineers (IEEE)
Mircea Ruba, Sebastian Ursache, Şerban Paula, Claudia Martis, Mihai Diţ, and Claudiu Oprea
IEEE
The paper presents a complete hands-on procedure for LFP battery parameters identification, several modelling approaches and state of charge (SOC) estimation based on Kalman Filter approach. The background of the paper reflects the development of a battery management system (BMS) for storage applications developed in a cooperation between the Technical University of Cluj Napoca, Romania and ROMBAT Romania, an industrial partner with its main activity in the field of battery production. Considering that the outcome must become a vendable solution, the authors investigate several methods of creating a battery model to be embedded into a real BMS. Benchmarking their operational skills is handled by comparative analysis between simulation of those models and actual measurements. To create these models, the battery parameters must be identified at cell level. Also, the SOC estimation, traditionally approached by coulomb counting is replaced by a more precise method, namely the Kalman Filter one. The results presented on different operational scenarios prove the accuracy of the models as well as the one of the SOC estimations, underlying the benefits of using such an approach for a real BMS.
Marius Drancă, Mihai Chirca, Ințe Răzvan, Sorin Cosman, Daniel Lates, and Claudiu Oprea
IEEE
This paper proposes an interior permanent magnet (IPM) synchronous motor as solution for an electric sled-type forest cableway. Design evaluation based on 2D finite-element field analysis proves that the IPM motor meets the necessary specifications. The study approaches also the thermal and demagnetization analysis with the aim to determine whether the permanent magnets on the rotor disk are subject to overheating during typical electric motor operation, which could result in permanent-partial demagnetization of the magnets.
Ioana-Cornelia Gros, Xiaoshu Lü, Claudiu Oprea, Tao Lu, and Lucian Pintilie
IEEE
The present review paper provides an overview of the recent advances in AI-based techniques for the design and optimization of power electronic converters. There is an increased demand on power converters in applications like renewable energy generation, microgrids, electric and hybrid vehicles, high-voltage DC power transmission etc. with focus on their design and optimization. In this context, various AI techniques are discussed, such as: machine learning, deep learning, reinforcement learning, and evolutionary algorithms, artificial neural networks, fuzzy logic control, expert systems and their applications in power electronics and electric drives. Some case studies from the literature are referred and potential benefits of AI-assisted design and optimization of power electronic converters with aspects of enhanced power system stability and performance are highlighted.
Gabriel Gheorghe, Daniel Lates, Claudiu Oprea, and Carmen Baltatu
Latvia University of Life Sciences and Technologies, Faculty of Engineering
This article presents the way to obtain the structural model for elementary linear-elastic static analysis of the moldboard of the plow. Also, to prove the functionality of the structural model obtained, the structural analysis results for the linear elastic static test are presented. These results are useful for estimating the safety factor and for assessing the behavior in major overstress situations at the main part of the machine. Structure dynamics is a very broad discipline that uses a huge arsenal of theoretical and experimental methods to solve the fundamental problem of structures: the dynamic response to variable tasks over time. Vibrations, and especially vibration in resonance modes, are problems that occur frequently in large structures. As large structures with large numbers of components cannot be optimally engineered for resonant regimes, it is often done to resolve structures or improve them by using the modal analysis of the mathematical models of these structures. The usefulness of this analysis is particularly evident in the testing phase and even in the first stages of operation when it is necessary to improve the working regime of a product of the type analyzed. The main results of the static linear-elastic structural analysis are the values of the reactions in the holders, vector field distribution of the relative – resultant displacement in the structure, tensor fields’ distribution of the specific deformation and the Cauchy stress tensor in the same structure. Also, an important result for structure safety is the distribution of the safety factor. The analysis of the equipment’s own spectrum allows proper identification of the main frequencies, at which a resonant working regime can occur as well as the necessary forces to choose the optimal vibration system.
Daniel Lates, Razvan Alexandru Inte, Mihai Chirca, Marius Dranca, and Claudiu Oprea
Springer International Publishing
Stefan Breban, Marius Dranca, Mihai Chirca, Alexandru-Madalin Pacuraru, Petre-Dorel Teodosescu, and Claudiu-Alexandru Oprea
MDPI AG
In an attempt to limit the effects of global warming, virtually all car manufacturers have introduced in the last years Hybrid or full Electric Vehicles. The current study shows the experimental testing of a spoke-type PMSM that was developed based on the requirements of the L6e European light vehicle class. A test bench was developed for this purpose, using a DC machine fed by a bidirectional DC Power Supply that allowed the testing of the PMSM prototype both in motor and generator/brake regimes. The Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP) was implemented on the control stage of the testing set-up, allowing an accurate estimation of the PMSM-based E-drivetrain performance. The test results validated the FEM-simulated results and provided an insight on the efficiency of the entire drive system (battery–inverter–PMSM) and the autonomy of the L6e light EV. The electric drive system was integrated and tested on a prototype vehicle in normal operating conditions, validating the results obtained on the developed test bench.
Mihai Chirca, Marius Alexandru Dranca, Stefan Breban, and Claudiu Alexandru Oprea
IEEE
The current study aims to determine the best propulsion machine for a Light Electric Vehicle compatible with L6e quadri-cycle constrains defined by the European Commission. The performance evaluation is made between two permanent magnet synchronous machine with different rotor topology, namely the spoke type rotor and the interior permanent magnets rotor.
Mihai Chirca, Marius Dranca, Claudiu Alexandru Oprea, Petre-Dorel Teodosescu, Alexandru Madalin Pacuraru, Calin Neamtu, and Stefan Breban
MDPI AG
This paper presents two electromechanical systems used for the overspeed protection of small wind turbines. The actuators have the purpose of rotating the back rudder (tail vane) of the wind turbine when the blades are overspeeding. The rudder rotation angle is 90 degrees in order to completely turn the wind turbine blades away from the wind flow direction. The first device is a new limited-angle torque electromechanical actuator consisting of a device with a simplified structure composed of four permanent magnets (two on each side) glued on a rotor mounted between two stator poles built from ordinary rectangular construction pipes and an electronic control unit. The second device is based on a regular stepper motor actuator with a reduction gear and an appropriate control scheme to maximize the energy harvested at high, over-nominal wind speeds. A generic comparison is provided for the proposed solutions.
Bogdan M. Mîndruț and Claudiu A. Oprea
Springer International Publishing
Claudiu Alexandru Oprea, Calin Iclodean, Mihai Chirca, Marius Dranca, Florin Ghita, and Stefan Breban
IEEE
The current study aims to determine a viable solution for the electric propulsion system for a Light Electric Vehicle compatible with the L6e quadri-cycle constraints defined by the European Commission. System level analysis is performed to determine the performances of different topologies of the electric propulsion system, considering in-wheel electric machines or conventional structures connected to the vehicle’s wheel directly or through a gearbox. The second part of the paper compares various Permanent Magnet Synchronous Machine topologies to determine the most suitable solution for the targeted application.
Sorin I. Cosman, Cristina A. Moldovan, Rares A. Iusan, Claudiu Oprea, and Claudia S. Martis
IEEE
The rhythm of rising food prices due to unjustified consumption of resources is a fairly pronounced problem and a technological optimization of greenhouses in which they are cultivated is necessary. The proposed automation system aims both to reduce production costs due to the efficiency of water consumption and the elimination of the human factor in certain maintenance and care works as well as the improvement of plant growth factors. Simulation of the system automation consists in the practical execution of a miniature greenhouse system with a scale of 1:10, controlled by a development board equipped with Arduino, temperature, humidity and light intensity measuring elements, modules for interfacing the microcontroller with the elements respectively the sprinkler water pump, the ventilation fan and the motors for opening and closing the ventilation hatch. The automation system can be applied and adapted to an authentic agricultural greenhouse irrespective of its dimensions, but taking into account the required power of the electrical machines.
Andreea-Madalina Nicorici, Claudiu Oprea, and Claudia Martis
IEEE
In this paper a 7.5 kW permanent magnet assisted synchronous reluctance machine (PMASynRM) with ferrite magnets for light electric vehicles propulsion is studied. Electromagnetic Finite Element Analysis (FEA) is used in order to evaluate the performance of the machine. The flux linkage, inductances and torque are evaluated on d-q axes. When torque is calculated, the magnetic co-energy is taken into consideration.
Sorin Iulian Cosman, Vasile Ionut Boanca, Claudiu Oprea, and Claudia Steluta Martis
IEEE
This paper deals with the design, construction and testing of a high-current and low-voltage drive for powering a Switched Reluctance Motor (SRM) used for an electric-driven compressor for Heat-Ventilation-Air-Conditioning (HVAC) applications used in full electric cars. The purpose of the study is to design and test a flexible and easy-to-control converter for a wide range of SRMs, taking into account the technical specifications of the compressor. In order to carry out the experimental work, a test bench based on a dSPACE board, an electronic converter, a Direct-Current Machine used as load, a torque transducer, a position transducer, temperature sensors and the SRM.
Gheorghe Badea
STEF92 Technology
Gheorghe Badea
Stef92 Technology
Arkadiusz Dziechciarz, Claudiu Oprea, and Claudia Martis
IEEE
This paper is focused on multi-physics (structural and electromagnetic) analysis of synchronous reluctance machine (SynRM). Rotor's construction of SynRM is designed to provide the best electromagnetic behavior of the machine. The number and shapes of flux barriers are chosen in order to maximize the machine's saliency ratio. However, at high rotational speeds due to high stress in the bridges, the rotor might be damaged. To prevent from braking the bridges, some additional ribs have to be introduced into rotor's construction. This modification affects electromagnetic properties of the machine, thus optimal construction of the rotor has to be found in terms of electromagnetic and structural behavior of the machine.
Mihai Chirca, Claudiu Oprea, Petre-Dorel Teodosescu, and Stefan Breban
IEEE
This paper approaches the electromagnetic design and finite-element analysis of a radial flux NdFeB permanent magnet synchronous machine for use as direct-driven generator with low speed micro-wind turbines. The design evaluation of the radial-flux spoke-type permanent magnet (RFPM) generator, based on 2-D and 3-D finite element field analysis, proves that this topology represents a good-performance and cost-effective and could be the machine of choice in grid-connected or stand-alone small-scale wind energy conversion systems.
Mihai Chirca, Stefan Breban, Claudiu Oprea, and Mircea M. Radulescu
IEEE
This paper investigates two topologies of ferrite-permanent-magnet synchronous machines for use as direct-driven generators in micro-wind power applications, i.e. the axial-flux double-sided inner-stator permanent-magnet (AF-PM) generator and the radial-flux spoke-type interior-permanent-magnet (RF-IPM) generator. The comparative design analysis of AF-PM and RF-IPM micro-wind generators based on finite-element field analysis proves that both topologies represent a good-performance and cost-effective solution of choice for micro-wind power applications.
Claudiu Alexandru Oprea, Claudia Steluta Martis, Petru Cristinel Irimia, Calin Husar, and Mihail Grovu
IEEE
The intent of this paper is to present an electromagnetic and structural study of a Synchronous Reluctance Machine. While most literature on the SynRM only considers the influence of rotor and stator geometry on the electromagnetic behavior of the machine, this paper introduces a combined approach, considering also the stress field in the machine's rotor due to inertial loads. The analysis is made for different construction solutions at different rotation speeds. The validation of static design is carried out with FEA solution. Some recommendations are made regarding possible solutions.
Cassio T. Faria, Remi Mongellaz, Claudiu Oprea, Fabrice Boon, Saphir Faid, and Thomas Thiemann
IEEE
This paper outlines the process of reluctance motors design for a particular subclass of electric vehicles. The work presented here describes the target setting process of the electric vehicles categories: City Electric Vehicle (CEV), Extended-Range Electric Vehicle (E- REV) and Plug-in Hybrid Electric Vehicle (PHEV). Based on system level simulation and a set of vehicle targets, motor specifications are defined together with a list of parameters to be used in the motor design process. Three different reluctance machines technologies are considered as candidate technologies to meet the requirements previously established: Switched Reluctance Machine (SRM), DC-Excited Flux-Switching Machine (DCEFSM) and Synchronous Reluctance Machine (SynRM). Each motor design process takes into account the electromagnetic, thermal, vibro- acoustic, system-level performance and power electronics aspects of each topology. A direct and objective comparison of the three competing technologies is carried out by an assessment process that allows the selection of a single reluctance machine type to be further developed. This work was part of the ARMEVA project, and European Commission FP7 funded initiative.
Claudiu Oprea, Arkadiusz Dziechciarz, and Claudia Martis
IEEE
Synchronous reluctance machines become more popular nowadays. Development of power electronics allowed reluctance motors to be used in many drive applications. Due to increased interest in electric vehicles and high prices of PMs, the research on electric drives is mainly focused on reluctance machines. Lack of rotor winding lowers copper losses, simplifies power supply system and increases machine's robustness. SynRM produces torque due to rotor's magnetic anisotropy, which is achieved in machines with transversally laminated rotor by introducing flux barriers. The main goal when designing rotor's flux barriers is to achieve the highest saliency ratio possible. However, since operation of the machine depends on interaction between stator magnetic field and the rotor, both stator and rotor's topologies should be taken into account when designing the machine. This paper presents a comparison of SynRMs with stators of three different slot numbers and two different rotor's topologies.
M. Chirca, S. Breban, C.A. Oprea, and M.M. Radulescu
IEEE
An analysis of variations of innovative design for double-sided inner-coreless-stator axial-flux permanent-magnet (AFPM) generators intended for micro-wind turbine applications is presented in this paper. The 3-D finite-element field analysis proves that design variations of ironless stator with non-overlapping concentrated winding, sandwiched between two opposing steel rotor disks with embedded circumferentially-magnetized ferrite permanent magnets (PMs) in flux-concentration arrangement, may represent good-performance and cost-effective double-sided topologies for AFPM machines in micro-wind power generation applications.