| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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