Lorenzo CarboneMario MarchesoniMassimiliano PassalacquaGianluca Postiglione...
3-15页
查看更多>>摘要：A medium voltage induction motor drive for a submarine oil pump is considered in this paper. In the considered application, the inverter is located on the oil platform, whereas the submersible oil pump is located under the sea and it is supplied with a 20-km long cable. Moreover, an LC filter is located at the inverter output on the platform. In addition, since all the motor sensors should be maintained with submarine robots, stator voltage, stator current and rotor speed sensors are not installed on the motor for reliability reasons. In this study, a new sensorless control is developed. The proposed control integrates a voltage drop compensation and a stator voltage-current estimation into a sensorless control based on a Luenberger Observer. The effectiveness of the proposed control is proved by experimental tests on a low voltage motor, on a 6.6 kV-710 kW motor and on a 2.1 MW-10.5 kV motor.
查看更多>>摘要：A large quantity of battery cells are required by each phase of the 35 kV large-capacity transformer-less battery energy storage system (LCTL-BESS) based on cascaded H-bridge converter (CHBC) and the parameters of battery cells are inconsistent. The inconsistencies of battery parameters should be fully considered in main circuit parameter design to improve the system's adaptability to them, thus delaying the aging rate of battery and ensuring the safety and high efficiency utilization during the whole life cycle of battery. The cascaded number of power modules in per phase is the most important main circuit parameter of system and has a significant influence on system performance, which should be optimized by considering system efficiency and safety comprehensively. Since the system efficiency and safety evaluation model are closely related to inconsistent battery parameters, it is impossible to establish them under different number of power modules based on the detailed parameters of each battery cell. Therefore, a method to establish system efficiency and safety evaluation model based on the capacity distribution of the battery cells is proposed. The massive battery cell parameter identifications and data processing are avoided. Our proposed method provides theoretical guidance for the optimization design of main circuit for LCTL-BESS. Additionally, the power and energy balancing control of 35 kV LCTL-BESS are investigated, and a novel energy balancing control strategy among modules considering the DC link voltage and state of charge (SOC) are proposed under the nearest level modulation (NLM), which can promise both the balancing effect and AC side output performance. Finally, the validity of the proposed parameter design method and the control strategy are proved through off-line simulation model.
Elisabet JanssonTorbjörn ThiringerEmma Arfa Grunditz
30-42页
查看更多>>摘要：This paper investigates the influence of flux barrier shape on the field-weakening performance of interior permanent magnet rotors with two layers of magnets. The field-weakening performance of four topologies, with different flux barrier shape, has been maximized using combined electromagnetic and mechanical optimization of the rotor geometry. The impact of the mechanical stress constraint on the optimization result is quantified. The rotor topologies differ in both their optimal balance between saliency and normalized magnet flux linkage, and in how severely they are affected by mechanical constraints. Including stress constraints strongly increased the differences between the rotor topologies and it was shown that careful handling of the mechanical constraints was of similar importance for the field-weakening performance as the shape of the flux barrier. Among the included topologies, the double V-shape design was found to have the highest power capability across the speed range and lowest sensitivity to mechanical constraints.
查看更多>>摘要：The AC characterization of solar photovoltaic (PV) cells typically employs electrical impedance spectroscopy (EIS) to ascertain internal dynamic impedance. However, EIS faces limitations in real-world applications, particularly under varying environmental conditions. The standard EIS method uses perturbation-based techniques tailored for specific frequency bandwidth measurements. To mitigate these issues, this paper introduces a direct continuous-time (CT) system identification strategy based on the recursive instrumental variable approach to estimate the AC equivalent electrical circuit (EEC) parameters of the solar PV. This CT identification method outperforms the EIS frequency technique in estimating AC EEC parameters under changing environments. It exploits the DC-DC boost converter's inherent switching characteristics, eliminating the need for an external excitation signal. The focus lies on the recursive instrumental variable method implemented using the Kalman filter. Simulation and experimental results validate the analysis and demonstrate the advantages of the CT system identification method in solar PV AC characterization applications. In the simulation, the EIS procedure and the system identification algorithm were compared to ground truth values. A Frequency Response Analyzer (FRA) was utilized to benchmark the experimental results estimated using the system identification method.
查看更多>>摘要：Permanent magnet linear synchronous motors (PMLSM) have their line-start performance enhanced with a conductive ladder arrangement in the “line-start PMLSM” design. However the thrust oscillation during the synchronisation in the non-salient structure is significant. To achieve stable synchronisation in practice, this paper develops a model-switching direct thrust and flux control (model-switching DTFC) theory for the line-start PMLSM. A general model is first established, which considers the longitudinal end effect and the eddy current produced by the conductive material of the ladder arrangement during transients. Then a conventional model is simplified into during steady-state periods at synchronous speed. Importantly conditions at which switching between models occurs are determined by the differential stator voltage between the general and the conventional model, with which the model-switching DTFC is designed. The proposed theory is applied to a prototype setup. Using experimental results, the model-switching DTFC is demonstrated to improve the kinetic performance of the line-start PMLSM. Both the overshoot and the steady-state ripple in the mover velocity can be improved by a factor of 2; 80% of underdamp and 50% of the thrust error can be eliminated. Therefore, the major contribution of this paper is improved control precision during reversals for the line-start PMLSM.
查看更多>>摘要：In this paper, a rotor reconstruction method based on the air-gap field coding is proposed to reduce iron losses of the partitioned stator flux-modulation (PSFM) machine. First, the armature and permanent magnet magnetomotive force (MMF) models are established, respectively. Considering the double air-gap modulation effect of the PSFM machine, the amplitude and rotation velocity of each harmonic are analyzed. Then, the contributions of each harmonic component in the air gap to iron losses are separated. Subsequently, an air-gap permeance model that determines the characteristics of harmonic components is established. On this basis, air-gap harmonics can be weakened by encoding the amplitude of the permeance. Simultaneously, the improved permeance harmonic components are reconstituted to guide the new rotor structure without optimizing parameters of the machine. The proposed rotor structure can effectively suppress the iron losses of the PSFM machine. Finally, a prototype of the rotor reconstructed PSFM machine is manufactured and tested to verify the effectiveness of the analytical results.
NETL
NSTL