| 1. |
- Kersten, Anton, et al.
(författare)
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Electric Vehicle Heating Management Techniques utilizing Drivetrain-Loss-Heating of Refrigerant
- 2022
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2022-October
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Konferensbidrag (refereegranskat)abstract
- Resistive cabin heaters can significantly reduce the driving range of battery electric vehicles in cold climate conditions. Heat pump solutions can mitigate this drawback, but these are also complemented with resistive heaters which are often unnecessary in warmer climates. This paper investigates different drivetrain-loss-heating techniques, which can be used as redundancy or as a replacement for the resistive heater. With the help of different software tools, the achievable electric drive unit (EDU) losses, considering the motor and inverter losses, of a Volkswagen ID.3 are simulated. When driving at lower speeds or standstill, the EDU losses can be regulated via the stator current magnitude. As demonstrated, this method increases the torque ripple, but the generated heat losses, varying from 5.8 kW to 7.9 kW, are sufficient to fulfill the cold climate heating requirements. When operated at standstill, a declutched motor can achieve comparable heat losses, but disconnectors are seldomly used in battery electric vehicles. When using balanced three-phase DC currents at standstill, the heat losses vary from 4.6 kW to 5.4 kW depending on the rotor position, which might not be sufficient to fulfill the required heating capacity at cold climates.
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| 2. |
- Xu, Yu, 1996, et al.
(författare)
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Comparative study of efficiency improvement with adjustable DC-link voltage powertrain using DC-DC converter and Quasi-Z-Source inverter
- 2023
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Ingår i: 2023 IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific). - 9798350314274
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Konferensbidrag (refereegranskat)abstract
- Adjusting the DC-link voltage in the electric pow-ertrain has proven to be beneficial for enhancing powertrain efficiency. This paper presents a comparative study between two adjustable DC-link voltage powertrain solutions: (1) Voltage Source Inverter (VSI) integrated with a DC-DC converter (VSI+DC-DC) and (2) Quasi-Z-Source Inverter (QZSI). Based on the different operation principles of the two solutions, DC-link voltage adjustment strategies have been proposed to maximize powertrain efficiency over drive cycle operation. With the help of simulation in the PLECS environment, the powertrain losses of the two solutions are examined over the WLTC drive cycle. The results suggest both solutions can achieve significant powertrain loss reduction compared to the conventional powertrain with fixed DC-link voltage. In addition, the QZSI solution sees a 20% higher loss in power electronics than the VSI+DC-DC solution, as the DC-link voltage in the QZSI solution has to be boosted to higher values. Nevertheless, from an overall powertrain perspective, the QZSI solution has only 3% higher powertrain losses compared to the VSI+DC-DC solution, making QZSI remain an attractive alternative for adjustable DC-link powertrain given its advantages such as fewer active switches and improved system reliability.
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| 3. |
- Xu, Yu, 1996, et al.
(författare)
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Improved efficiency with adaptive front and rear axle independently driven powertrain and disconnect functionality
- 2023
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Ingår i: Transportation Engineering. - 2666-691X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Front and rear axle independently driven (FRID) powertrains are becoming a popular solution for electric vehicles (EVs) due to torque distribution capability which can enhance powertrain energy efficiency. Typically, permanent magnet synchronous machines (PMSMs) are used for FRID powertrains due to their high torque, and power density. However, the drive-cycle efficiency of FRID powertrains with PMSMs is typically reduced in comparison to single motor drives. This is due to the unwanted no-load losses of PMSMs in the field weakening region. To overcome this drawback of PMSM FRIDs, this paper proposes an adaptive front- and rear-axle independently driven (AFRID) powertrain, utilizing two dog clutches, so that the powertrain can be operated in different modes (rear, front, and all-wheel drive) by adaptively connecting and disconnecting the front and/or rear electric drive unit (EDU). A rule-based mode selection strategy is developed to utilize the flexibility of different powertrain operating modes of the powertrain for maximizing the energy efficiency of the EDU. The simulation results show that the suggested AFRID powertrain, in comparison to a common FRID powertrain, can improve the WLTC drive-cycle consumption from 22.17 kWhh to 20.50 kWhh per 100 km. Based on the route and road-load information, the energy-saving potential of the AFRID powertrain can be further improved to 20.37 kWhh per 100 km by a suggested predictive mode selection strategy, achieving an optimal mode selection.
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| 4. |
- Xu, Yu, 1996, et al.
(författare)
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Maximizing Efficiency in Smart Adjustable DC Link Powertrains with IGBTs and SiC MOSFETs via Optimized DC-Link Voltage Control
- 2023
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Ingår i: Batteries. - 2313-0105. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the push towards electrifying transportation has gained significant traction, with battery-electric vehicles (BEVs) emerging as a viable alternative. However, the widespread adoption of BEVs faces multiple challenges, such as limited driving range, making powertrain efficiency improvements crucial. One approach to improve powertrain energy efficiency is to adjust the DC-link voltage using a DC-DC converter between the battery and inverter. Here, it is necessary to address the losses introduced by the DC-DC converter. This paper presents a dynamic programming approach to optimize the DC-link voltage, taking into account the battery terminal voltage variation and its impact on the overall powertrain losses. We also examine the energy efficiency gains of IGBT-based and silicon carbide (SiC) MOSFET-based adjustable DC-link voltage powertrains during WLTC driving cycles through PLECS and Matlab/Simulink simulations. The findings indicate that both IGBT and MOSFET-based adjustable DC-link voltage powertrains can enhance the WLTC drive-cycle efficiency up to 2.51%2.51% and 3.25%3.25% compared to conventional IGBT and MOSFET-based powertrains, respectively.
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| 5. |
- Xu, Yu, 1996
(författare)
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Novel powertrain topologies for energy-efficient battery electric vehicles
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The global transition towards sustainable transportation has underscored the importance of battery electric vehicles (BEVs), with a growing need for enhancement in powertrain energy efficiency to mitigate range anxiety and promote widespread adoption. In response to this need, there have been significant contributions from advancements on powertrain components, such as electric motors and inverters, towards increased energy efficiency. However, it is crucial to acknowledge that BEV powertrain efficiency is not simply a product of the efficiencies of electric motors and inverters. In this context, the exploration of novel powertrain topologies presents itself as an alternative and promising approach for further enhancing BEV powertrain efficiency. Moreover, when component-level advancements are integrated with innovative powertrain topologies, there is potential to push the boundaries of powertrain energy efficiency in BEVs. To this end, system simulation techniques are utilized in this thesis to evaluate different powertrain topologies in terms of energy efficiency over standard drive cycles, each operating under its optimal powertrain strategy. Specifically, two powertrain topologies are investigated in this thesis: 1) the Adaptive Front- and Rear-Axle Independently Driven (AFRID) powertrain features two clutches that enable the mechanical disconnection of two electric motors with differentiated high-efficiency operating areas, aiming to address the inherent high no-load losses of dual motor powertrains while utilizing the high-efficiency zone of each motor and leveraging torque distribution functionality to enhance overall efficiency. 2) The adjustable DC-link voltage powertrain allows the adjustment of DC-link voltage to an efficiency-favored level irrespective of the battery voltage, in response to dynamically changing driving conditions. The findings of this thesis indicate that the integration of both investigated powertrain topologies with state-of-the-art components can significantly enhance powertrain energy efficiency in comparison to conventional BEV powertrains. Importantly, these improvements in efficiency do not come at the expense of vehicle performance or driveability; in fact, vehicles equipped with these novel powertrain topologies are observed to exhibit superior performance and improved driveability, making them highly favorable options for the next generation of BEV powertrains.
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