| 1. |
- Huang, Zhifeng, et al.
(författare)
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Three-dimensional posture optimization for biped robot stepping over large ditch based on a ducted-fan propulsion system
- 2020
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Ingår i: IEEE International Conference on Intelligent Robots and Systems. - 2153-0858 .- 2153-0866. ; , s. 3591-3597
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Konferensbidrag (refereegranskat)abstract
- The recent progress of an ongoing project utilizing a ducted-fan propulsion system to improve a humanoid robot's ability to step over large ditches is reported. A novel method (GAS) based on the genetic algorithm with smoothness constraint can effectively minimize the thrust by optimizing the robot's posture during 3D stepping. The significant advantage of the method is that it can realize the continuity and smoothness of the thrust and pelvis trajectories. The method enables the landing point of the robot's swing foot to be not only in the forward but also in a side direction. The methods were evaluated by simulation and by being applied on a prototype robot, JetHR1. By keeping a quasistatic balance, the robot could step over a ditch with a span of 450 mm (as much as 97% of the length of the robot's leg) in 3D stepping.
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| 2. |
- Jiang, Bowen, 1993, et al.
(författare)
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A New Battery Active Balancing Method with Supercapacitor Considering Regeneration Process
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2020-October:18 October 2020, s. 2364-2369
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Konferensbidrag (refereegranskat)abstract
- Lithium-ion batteries have been widely used in new energy vehicles (NEV) as large energy storage systems (ESS). It is necessary to balance series-connected cells to avoid over-charging or over-discharging as well as to improve the amount of usable energy. This paper starts with a comprehensive review of the existing strategies and gives a battery balancing category. A new balancing topology with its control algorithms is then introduced. A supercapacitor is used in the balancing circuit which replaces the highest state of charge (SOC) cell and is charged during the vehicle regeneration process. The supercapacitor also transfers energy to the lowest SOC cell after it is fully charged. This new strategy can not only improve the balancing efficiency due to fewer times of energy conversion but also reduce the required balancing time compared to single capacitor balancing.
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| 3. |
- Mademlis, Georgios, 1992, et al.
(författare)
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Circulating Current Reduction in Common DC-Link Power-HIL for Drives using SVM with Zero-Sequence Compensation
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2162-4704 .- 2577-1647. ; , s. 4673-4678
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Konferensbidrag (refereegranskat)abstract
- A new zero-sequence control technique is presented in this paper in order to eliminate the circulating current flowing in power hardware-in-the-loop test benches for electrical machine emulators. The machine emulator studied in this paper is made up of two three-phase inverters with an inductor connecting their ac-side. Both inverters share the same dc-link allowing circulating flow of the electric energy within this loop in order to emulate the operation of high power machine drives. Unfortunately, common-mode voltage is also freely developed within the loop and creates high circulating currents that act as a disturbance for the control of the inverters. Available control techniques have not managed to completely eliminate this current and common-mode filters are used additionally in order to solve the problem. The proposed zero-sequence control utilizes a modified version of the space vector modulation and reduces the circulating current amplitude up to 2.1% of the phase current, eliminating the need for hardware filters. Simulation results from Matlab/PLECS verify the effectiveness of the developed controller.
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| 4. |
- Pehrman, Daniel, 1988, et al.
(författare)
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Loss Reduction by Synchronous Rectification in a 50 kW SiC-based Inductive Power Transfer System
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2020-October, s. 3907-3912
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Konferensbidrag (refereegranskat)abstract
- With development in wide band-gap semiconductors, such as silicon carbide (SiC), inductive power transfer (IPT) has become a promising technology for charging electric vehicles (EV). To meet fast charging demands by consumers, higher power levels in IPT is required. The power in IPT is usually limited by thermal stress due to losses at the vehicle side. Synchronous rectification is an efficient way to reduce losses compared to passive rectification. In this paper, the loss reduction accounted to synchronous rectification is quantitatively evaluated. The level of reductions varies depending on the load level, primary voltage, and constant current or constant voltage (CCCV) operation. The analytical results support the simulation results for various operating points. The loss profiles are studied for different dc-link voltages and duty cycles. An 800 V, 50 kW dual-active bridge test setup with series-series compensation is constructed and experiments are done for verification. The setup is arranged in a back-to-back configuration with a common dc-link. Experimental result shows that losses are reduced by up to 60 % on the receiving side with synchronous rectification. At rated operation the losses are reduced by 100 W in the secondary side inverter.
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| 5. |
- Rodionov, Artem, 1990, et al.
(författare)
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Analysis of DC Link Current and Voltage Stress for Motor Drive Application in Dual Three-Phase Configuration
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2020-October, s. 1267-1272
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Konferensbidrag (refereegranskat)abstract
- In automotive applications both space and operational safety of the drive-train are important design considerations. In this study a thorough DC link design for a fault tolerant dual three-phase drive train is conducted. PWM interleaving technique is utilized and based on the three-phase reference case DC link sizing maps in terms of both current and voltage stress are obtained for dual-three-phase configurations.It is found that current stress of the DC link capacitor can be reduced by up to 46 % compared to the three phase case. Similarly, the voltage stress can be reduced by up to 45 % while maintaining fault tolerant capability.
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| 6. |
- Sharma, Nimananda, 1988, et al.
(författare)
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Design of a power hardware-in-the-loop test bench for a traction permanent magnet synchronous machine drive
- 2020
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Ingår i: Proceedings - 2020 International Conference on Electrical Machines, ICEM 2020. ; , s. 1765-1771
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Konferensbidrag (refereegranskat)abstract
- The challenges in inverter development for traction applications are low cost, better performance, optimized design and faster time to market. A solution is to use machine emulators whose phase currents and voltages at the terminal resembles a machine connected to a mechanical load for testing. Testing of an inverter for traction applications using permanent magnet synchronous machine (PMSM) emulator is presented. The emulator test bench consists of two identical front-to-front connected 2-level voltage source converters connected via an auxiliary inductor. Verification of the emulator is carried out in MATLAB/PLECS by comparing simulated phase currents, torque and rotor speeds to an equivalent PMSM drive. A common dc-link is used between the emulator and the inverter under test resulting into circulating common-mode currents. A common-mode choke and controller is used to eliminating common-mode currents. It is shown that the emulator can effectively emulate the PMSM drive with reasonable accuracy.
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| 7. |
- Song, Kai, et al.
(författare)
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Constant Current Charging and Maximum System Efficiency Tracking for Wireless Charging Systems Employing Dual-Side Control
- 2020
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Ingår i: IEEE Transactions on Industry Applications. - 0093-9994 .- 1939-9367. ; 56:1, s. 622-634
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Tidskriftsartikel (refereegranskat)abstract
- Wireless power transfer (WPT) systems have attracted much attention because of their safety, convenience, and environmental friendliness. For wireless supercapacitor charging, the system efficiency and charging current are highly dependent on the load that varies over a wide range. In this article, a simultaneous maximum system efficiency (MSE) tracking and constant current (CC) charging control scheme for a supercapacitor is proposed. For CC charging, a double-sided LCC topology is chosen due to its characteristic of providing a load-independent output current. Furthermore, the impact of the coil internal resistance on the system characteristics (especially the charging current) is investigated, so a semiactive rectifier is introduced on the secondary side to achieve accurate CC charging and improve the system robustness. Based on the variable-step perturbation and observation algorithm, the MSE is tracked by searching for the minimum system input dc current using a primary-side buck converter on the premise that the charging current reaches its target value. The abovementioned two control loops are independent, and mutual communication is unnecessary when they cooperate; thus, the system is simplified. The simulation and experimental results show great consistency with the theoretical analysis. The experimental system maintains the MSE of 86% during charging the supercapacitor from 20 to 50 V with 2 A.
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| 8. |
- Xun, Qian, 1990, et al.
(författare)
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Intelligent Power Allocation with Load Disturbance Compensator in Fuel Cell/Supercapacitor System for Vehicle Applications
- 2020
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Ingår i: ITEC 2019 - 2019 IEEE Transportation Electrification Conference and Expo. - 9781728146294 ; , s. 489-494
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Konferensbidrag (refereegranskat)abstract
- A fuel cell-based hybrid power system with a supercapacitor can downsize the fuel cell power rating and shows good dynamic characteristics. However, power distribution between fuel cell and supercapacitor is challenging, and inappropriate power allocation strategy will easily cause over-charge or overdischarge of supercapacitor. Also, the DC bus voltage fluctuation is always encountered during the acceleration and deceleration of the vehicle. This paper proposes an intelligent power allocation method based on a low-pass filter. The adaptive cut-off frequency is applied to avoid over-charging and over-discharging the supercapacitor, and the cut-off frequency is calculated by cutting the load spectrum with allocation ratio changing with the state of charge (SoC) of the supercapacitor. A load disturbance compensator is also proposed to suppress the DC bus voltage fluctuation when the load variation occurs. According to the hybrid system model developed with commercially available devices, the feasibility of the strategy is verified by MATLAB/Simulink. The simulation results show that the SoC of the supercapacitor is effectively controlled and the DC bus voltage fluctuation is significantly reduced.
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