| 1. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Balancing Peak-torque and Drive-cycle Efficiency with Magnet Dimensioning of Permanent Magnet Synchronous Machines
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2020-October, s. 883-888
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Konferensbidrag (refereegranskat)abstract
- There is an increasing trend in reducing rare-earth materials due to environmental and cost concerns. It affects design and manufacturing of Permanent Magnet Synchronous Machines (PMSM). Changes in parameters such as size and shape of the magnets will affect requirements as operating efficiency and maximum torque. In this paper, the design of a 250 kW PMSM for a commercial heavy-duty vehicle application is considered in order to evaluate effects of magnets thickness variation on performance and driving cycle efficiency. With this aim, an electromagnetic model is built using Finite Element Method (FEM) and efficiency map computations are carried out to investigate the effects of the magnet variation. System simulations are then implemented in MATLAB/PLECS to evaluate the driving cycle efficiency. Simulation results shown that the reduction of magnet thickness leads to significantly improved operating efficiency with reduction of maximum torque.
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| 2. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Convective Heat Transfer Coefficients and Mechanical Loss Evaluation of Oil Splashing in Direct Cooled Electrically Excited Hairpin Motors
- 2022
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Ingår i: 2022 International Conference on Electrical Machines, ICEM 2022. ; , s. 496-503
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Konferensbidrag (refereegranskat)abstract
- There in an increasing trend in the use of the direct oil cooling in electric motors for automotive because of the increasing demand of high power/torque density as well as overload capability. One of the most immediate solution is to fill the housing with some oil level and benefit of the heat transfer from the oil splashing. The mechanical losses coming from the rotor rotation are well known and they represent a significant challenge, especially at high speed and high oil level. Therefore, the derivation and prediction of these losses have not been properly investigated leading to a lack in the current literature. Moving Particles Simulation (MPS) method is used in Particleworks to calculate the mechanical losses caused by the oil viscosity and convective heat transfer coefficients (HTC) are extracted for a 250 kW Electrically Excited Synchronous Machine at different speeds and oil levels.
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| 3. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Design and Verification of an Electrically Excited Synchronous Machine Rotor with Direct Oil Cooling for Truck Applications
- 2024
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Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- The rotor cooling in Electrically Excited Synchronous Machines (EESM) poses significant challenges due to the high power density resulting from active conductors necessary for generating the DC field, which in turn leads to substantial heat generation. Additionally, the rotor rotation further complicates the cooling system and contributes to mechanical losses. This paper presents the design of the rotor cooling system for a 200 kW EESM for truck applications. The system employs simultaneous direct cooling of the hollow shaft, rotor lamination, and rotor winding using mineral oil. The design is verified in simulations using Conjugate Heat Transfer (CHT) method by analyzing the oil flow and temperature distribution. Experimental tests are conducted on an 8-pole prototype rotor in stationary condition with a maximum coil heat loss of 4.7 kW, enabling 8x190 Aturns magneto-motive force per pole with 9.2 L/min oil flow rate. The results demonstrate the effectiveness of the cooling method in doubling the possible current density for continuous operation, from 5.05 A/mm2 to 10.1 A/mm2, keeping the Startup condition for more than 5 min and the maximum power for 20 minutes when the ventilation effect for the rotor rotation is included in simulation.
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| 4. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Numerically-based Reduced-order Thermal Modeling of Traction Motors
- 2021
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Ingår i: IEEE Transactions on Industry Applications. - 0093-9994 .- 1939-9367. ; 57:4, s. 4118-4129
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach based on numerical reduced-order modeling to analyze the thermal behavior of electric traction motors. In this study, a single conjugate heat transfer analysis provides the possibility to accurately predict thermal performances by incorporating both computational fluid dynamic and heat transfer modules. Then, the developed model is used as the basis for deriving a fast reduced-order model of the traction motor enabling prediction of motor thermal behaviour in duty cycles with a high number of operating points. All the results achieved are verified using flow and temperature measurements carried out on a traction motor designed and built for a traction application. A good agreement between the measured and estimated values of flows and temperatures is achieved while keeping the computation time within a reasonable range for both the full-order and reduced-order conjugate heat transfer models. The optimized full-order model can be run in minutes and the reduced-order model computation time is less than one second per operating point. The transient simulation based on reduced-order model is conducted and both the learning phase and validation results are well illustrated. It is shown than the deviation of the reduced-order model in estimating the motor thermal performance is less than one Celsius degree from the full-order model.
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| 5. |
- Boscaglia, Luca, 1991, et al.
(författare)
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Thermal Modeling and Driving-cycle Critical Temperatures Estimation of Electrically Excited Synchronous Machine for Automotive Traction
- 2023
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Ingår i: 2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023. ; , s. 4501-4508
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Konferensbidrag (refereegranskat)abstract
- Electrically Excited Synchronous Machines (EESM) has garnered attention due to their outstanding performance characteristics but it presents significant thermal challenges. The rotor is embedded with active conductors resulting in a high loss density and large amount of heat that discourage the adoption of this machine in various applications. This paper investigates into the feasibility of utilizing a 60 kW EESM for a commercial vehicle application, with a specific focus on understanding its thermal behavior. Steady-state 3D Conjugate Heat Transfer (CHT) analysis is conducted to obtain the temperature response of various machine components across the torque-speed map. Based on this analysis, thermal resistances are estimated to construct a simplified Lumped Parameter Thermal Network (LPTN) and predict maximum temperatures along the Worldwide harmonized Light-duty vehicles Test Cycles (WLTC). Simulations in MATLAB Simulink show that the temperatures remain below the limits defined by the winding insulation class throughout the entire driving cycle. This finding assures the reliability and safe operation of the EESM for the considered application.
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| 6. |
- Chen, Hao, et al.
(författare)
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Electromagnetic Performance Investigation of A Brushless Electrically-Excited Synchronous Machine for Long-Distance Heavy-Duty Electric Vehicles
- 2024
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Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- Long-distance heavy-duty electric vehicles, e.g., electric trucks, expect demanding requirements from the electric drive system, including high starting torque, high torque density, high power factor, high efficiency, etc. Permanent magnet synchronous machines (PMSMs) have been widely used for traction applications. However, the high cost and associated environmental issues due to the rare-earth permanent magnet material intensify researchers to explore new solutions. Accordingly, a brushless electrically-excited synchronous machine (EESM) is designed and investigated in this paper. The brushless EESM is also quantitatively compared with a PMSM candidate for the aforementioned application. Differing from conventional EESMs in which the brushes and slip rings are used for rotor field winding excitation, a contactless/brushless rotating transformer is adopted for the presented EESM to feed the rotor field winding. It is shown that the interior PMSM exhibits higher efficiency in low-speed region, but lower efficiency in high-speed region. By contrast, the brushless EESM exhibits lower efficiency in low-speed region, but much higher efficiency in high-speed region. Hence, the EESM is more suitable for long-distance heavy-duty electric vehicle applications where significant highspeed operations are required. Moreover, compared to the PMSM, the EESM is more cost-effective, sustainable, and environmentally friendly due to the absence of the rare-earth permanent magnet material. Both the PMSM and the EESM are prototyped and manufactured. Experimental results are provided to validate the effectiveness of the presented designs.
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| 7. |
- Jiang, Bowen, 1993, et al.
(författare)
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Active Balancing of Reconfigurable Batteries Using Reinforcement Learning Algorithms
- 2023
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Ingår i: 2023 IEEE Transportation Electrification Conference and Expo, ITEC 2023.
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Konferensbidrag (refereegranskat)abstract
- In reconfigurable batteries, series or parallel connections among cells/modules are able to be actively changed during operations. One big advantage of reconfiguration is to achieve active balancing among cells/modules. Rule-based and greedy algorithms of reconfigurable battery control have problems of being sensitive to battery characteristic variation and requiring a lot of computing resources. Therefore, deep reinforcement learning (DRL) algorithms are used to overcome these difficulties. Very few studies related to this idea have been done previously, and the studied battery reconfiguration topologies are either too simple or too complex. Thus, in this paper, a module-level reconfigurable battery with moderate flexibilities is controlled by DRL algorithms. Two neighboring modules are connected in either parallel or series by following a well-trained optimal policy. Two battery discharging cases, constant power and variable power, are simulated. The final results prove the feasibility and great potential of utilizing DRL algorithms in reconfigurable battery control.
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| 8. |
- Mademlis, Georgios, 1992, et al.
(författare)
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Performance Evaluation of Electrically Excited Synchronous Machine compared to PMSM for High-Power Traction Drives
- 2020
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Ingår i: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. - 9781728199450 ; , s. 1793-1799
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Konferensbidrag (refereegranskat)abstract
- The electric drive design for heavy-duty vehicles ischallenging due to special requirements involved, such as highstarting torque and operation at the peak power for a longtime. The electrically excited synchronous machine (EESM) is asuitable machine type for such an application and a potentialalternative to the permanent magnet synchronous machines(PMSM) due to the superior flexibility that the control of thebrushless rotor excitation offers. The direct adjustment of theflux allows also to tune the best efficiency region of the machineclose to the usual operating points of the vehicle achieving at thesame time a better power factor compared to a PMSM, whichcan further increase the efficiency and the power capability ofthe stator inverter. A case-study comparison of a EESM- andPMSM-based drive for electric trucks is presented in this paperwhere Finite-Element-Method and Matlab simulations of thewhole vehicle drivetrain showcase the advantages of the EESM.
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| 9. |
- Tang, Junfei, 1990, et al.
(författare)
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Comprehensive Dynamic Current Control of Electrically Excited Synchronous Machines With Magnetic Mutual Couplings
- 2024
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; In press
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Tidskriftsartikel (refereegranskat)abstract
- Electrically excited synchronous machines have become an attractive solution to electric vehicles. The excitation of the machine is controllable by adjusting the field current. However, due to the magnetic mutual couplings between stator and rotor windings, a voltage will be induced in the stator winding in case of a current rise in the field winding and vice-versa. In this article, a dynamic current control algorithm is proposed in which magnetic mutual couplings are comprehensively taken into consideration. To achieve this, first, the expected current derivatives are determined according to the error. Then, the voltages across all self- and mutual inductances are calculated correspondingly. In the end, the resistive voltages, inductive voltages, and the cross-coupling terms are summed up to construct the total controller output. To make sure that the control still works when the voltage output limit is reached, an antiwindup algorithm with adaptive bandwidth is proposed to cooperate with the dynamic current control algorithm. The results from simulations and experiments show that smoother responses can be achieved with the proposed control method.
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| 10. |
- Tang, Junfei, 1990, et al.
(författare)
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Observations of Field Current and Field Winding Temperature in Electrically Excited Synchronous Machines with Brushless Excitation
- 2022
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Ingår i: 2022 International Conference on Electrical Machines, ICEM 2022. ; , s. 841-847
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Konferensbidrag (refereegranskat)abstract
- Electrically excited synchronous machines have become an alternative in electrification of transportations and renewable power generations. To reduce the extra effort in the maintenance of sliprings and brushes for field excitation, brushless excitation has been developed. However, when brushless excitation is adopted, the field winding becomes physically inaccessible when the machine is rotating. To solve this problem, an algorithm is proposed in this study to observe the field current and field winding temperature of an EESM with brushless excitation. The stator currents are measured and then used to correct the machine state predictor. The correction of the state prediction is interpreted to adjust the field winding resistance and temperature value. The algorithm is evaluated in simulations. The estimations of field current and field winding temperature track the measurements successfully.
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