1,721,070 research outputs found
Esercizi di Macchine Elettriche - Seconda edizione
No full textLa raccolta di esercizi che viene qui proposta fa seguito alle numerose richieste da parte degli studenti di avere a disposizione esempi di soluzioni di esercizi numerici.
Il lavoro svolto ha compreso innanzitutto la collezione degli esercizi proposti negli anni dai vari Docenti del Dipartimento di Ingegneria Elettrica (ora Energia) ai quali va pertanto rivolto un doveroso e sentito ringraziamento.
La raccolta comprende 43 esercizi svolti su circuiti magnetici, trasformatore, macchina in corrente continua, macchina asincrona e riscaldamento delle macchine; essa è corredata da 124 figure e riteniamo possa essere utile per una miglior comprensione del funzionamento delle macchine elettriche e per la preparazione all’esame
Seamless Transition to Sensorless Control of EV Traction IPM Motors Using Virtual High-Frequency Voltage Injection
No full textDue to the possible malfunction or failure of the position sensor mounted on an electrical vehicle (EV) traction motor, a backup position sensorless torque control strategy is required. The switching-on-the-fly seamless transition from sensored mode to sensorless mode is particularly challenging at low-speed operation, where high-frequency injection (HFI) is usually employed to estimate the rotor position and speed through a tracking observer that must be properly initialized. Therefore, this paper proposes a virtual high-frequency voltage injection technique that is able to achieve a seamless transition between sensored mode and sensorless mode for interior permanent magnet (IPM) motors in EV traction drives. Detailed experimental validation is provided for a 157kW EV traction IPM motor mounted on a test rig
Grid-Feeding Inverter with Simplified Virtual Synchronous Compensator Providing Grid Services and Grid Support
Full text linkThispaperproposestheenhancementofthecontrolof agrid-connectedinverterbyasimplifiedvirtualsynchronouscompensator (S-VSC) model working in parallel with the traditional inverter current control loops. The goal of the integration of this model into the inverter control scheme is to provide grid services, such as virtual inertia behavior, current harmonic compensation, aswellasreactivegridsupportduringfaults.TheS-VSCisonlyin charge of providing the aforementioned services, working, therefore, always at a low power level. On the other hand, the main power references are sent directly to the inverter control loops. This way, a more stable and damped operation of the inverter is obtained. The proposed structure has been implemented on a 15 kVA grid-connected inverter for experimental validation
Fast Simulator for the Estimation of Inverter DC-link Temperature in e-Drives Subjected to Highly Variable Working Cycles
No full textAccurate estimation of losses and operating temperatures is extremely important for the design of traction inverters and its validation for specific operating conditions. Although several methods are already available in the literature to estimate the semiconductor power losses, the power losses and temperature evaluation of inverter DC-link capacitors are less explored. Therefore, this paper presents a fast simulation model of traction eDrive to provide accurate estimation of DC-link loss and temeperature, as well as DC link voltage ripple evaluation. The proposed model is implemented in Simulink and consists of both a loss model based on loss maps and a circuital model to estimate the dc-link voltage ripple. This model is very fast and therefore it is very useful when the eDrive is subject to long and highly variable driving cycles. Moreover, the model accounts for the influence of the main parts of the powertrain and allows a proper verification of the selected DC link capacitor
Overview of Sensorless Control Strategies for Electric Vehicle Traction IPMSM
No full textSensorless control of electric drives can eliminate the use of position sensor during operation, thus increasing reliability and decreasing cost of the drive. Many methods have been proposed and commercialized in industrial applications such as fans, pumps and home appliances. In case of electric vehicle (EV) traction application encoder is normally used, hence sensorless control provides back-up in case of encoder failure. The aim of the paper is to provide an overview of sensorless control methods
used or likely to be used on EV traction motors. Overall, EV motors have high power density and can operate under heavy saturation, thus not every sensorless method is suitable, and operating range is likely to be limited in sensorless mode. Our goal is to identify which sensorless control techniques are more suitable to be embedded in the control of EV traction motor
Optimal High-Frequency Injection Minimizing High-Frequency Torque Ripple for Sensorless Control of Electric Vehicle IPM Traction Motors
No full textA high-frequency (HF) torque ripple-free sinusoidal HF injection-based sensorless control technique is proposed for electric vehicle (EV) traction motors. The sensorless control is developed for interior permanent magnet (IPM) synchronous machines, which is the most commonly used motor type in EV traction applications. The HF torque ripple minimization is performed by injecting sinusoidal voltage along an optimal injection angle in the estimated rotor-aligned dq frame, which varies with the operating point. The magnetic saturation and cross-saturation that affect the operation of most traction motors are properly taken into account. The effectiveness, stability, and parameter sensitivity of the proposed method have been experimentally verified on a commercial 157 kW IPM traction motor mounted on a test rig
Digital Multi-Loop Control of a 3-Level Rectifier for Electric Vehicle Ultra-Fast Battery Chargers
Full text linkThis paper proposes a digital multi-loop control strategy for a 3-level unidirectional rectifier specifically targeted to electric vehicle (EV) ultra-fast charging applications. The basic operation of a 3-level rectifier is described and the state-space model of the complete system is explained, with particular focus on the mid-point current generation process. By means of an appropriate modeling of the delays and the discretization introduced by the digital control implementation, four controllers (i.e. dq-currents, DC-link voltage and mid-point voltage balancing loops) are analytically designed in the continuous time domain with conventional techniques. Ultimately, the proposed controller design procedure is tested on a 50 kW, 20kHzT-type rectifier, both in simulation and hardware-in-the-loop (HIL) environments, verifying the dynamical performance of all control loops
Ricarica ultraveloce: sfide e opportunità
No full textLa ricarica ultraveloce delle auto
elettriche preoccupa i gestori della rete.
L'elevato e intermittente assorbimento
di potenza pone ardue sfide al sistema
elettrico. E se invece nascondesse
un'opportunità
Analysis and Optimization of Polarity Detection Methods for Electric Vehicle Traction IPMSM
No full textInterior permanent magnet synchronous motors are used in the traction drive of most modern vehicles. These machines are designed to have a high power density, and they are likely to operate under heavy saturation.
Therefore, they exhibit strong magnetic nonlinearity, which poses challenges to sensorless control. For the startup of a sensorless electric drive, polarity detection is crucial, since an unstable control action could be induced if the 180 degree angle estimation error is not corrected. This work revisits the polarity detection fundamentals and their decision logic, applied to a real 157 kW IPMSM drive for electric vehicle applications. As proved, this kind of motor may have locally inverse saturation characteristics, so the polarity detection decision logic should be refined accordingly. Analysis and experimental validation are put together along the paper in order to stress wrong assumptions (from state-of-the-art) and implementation solutions that fit with the motor
Modulation Strategy Assessment for 3-Level Unidirectional Rectifiers in Electric Vehicle Ultra-Fast Charging Applications
Full text linkThis paper proposes a complete analysis and comparison of the most significant pulse-width modulation (PWM)
strategies for unidirectional 3-level rectifiers. The basic operation of the converter is described and the stresses on the major
passive components (i.e. DC-link capacitors, differential-mode
inductors, common-mode chokes) are calculated, highlighting
the general performance trade-off of each modulation strategy.
This analysis is applied to a rectifier for electric vehicle (EV)
ultra-fast charging connected to the European low-voltage grid
(i.e. 50 Hz, 400 V line-to-line), adopting a 650 V DC-link. The
best candidates concerning different performance metrics are
identified and the most suitable strategy for EV battery charging
is selected
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