A review of foreign object detection (FOD) for inductive power transfer systems
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Zhang, Yiming↗
Engineering topics
Mi, Chris
Publications and source records attributed to Mi, Chris.
Interoperability study of fast wireless charging and normal wireless charging of electric vehicles with a shared receiver
Fast charging of electric vehicles (EVs) has been the trend recently. For conductive charging, normal charging can be realised by an on‐board charger, while fast charging can be realised by a DC charger which is usually off‐board the vehicle. However, for wireless charging, there is a need of a transmitter on the ground and a receiver on the EV side. Therefore, there will be a high‐power receiver and a low‐power receiver in one EV to achieve dual charging capabilities. To reduce the EV‐side cost, weight, and volume, this paper proposes a wireless charging system with a shared receiver compatible of fast wireless charging (FWC) at a small air gap and normal wireless charging (NWC) at a large air gap. The relationship between the coil size and the power level is investigated and a suitable receiver coil size is selected for FWC. The LCC‐LCC topology is selected due to its characteristic of output power proportional to the coupling coefficient. Design procedures of the receiver and transmitters are investigated. The simulations and the experimental results obtained from the downscaled prototype verified the effectiveness of the compatibility design.
Zhang, Yiming↗
Double-sided LCLC-compensated topology for capacitive power transfer
A double-sided LCLC-compensated network is proposed for a capacitive power transfer (CPT) system. In one design, four metal plates are used to form two power transmitting and receiving capacitors and the LCLC network is used to compensate the capacitors. In the second design, two extra metal plates are used to couple with the previous four plates at the transmitting and receiving side, respectively, which forms the capacitor-integrated structure. The circuit parameter values are tuned to achieve zero voltage switching (ZVS) of the input side switches. There is also a CLLC topology proposed, which is a similar variation of LCLC circuit. A 3.3 kW input power capacitive power transfer prototype is designed and built. The experiment results show that the proposed CPT system can transfer 3.1 kW output power through an air gap distance of 70 mm with a dc-to-dc efficiency of 92.1%.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Single phase bi-directional AC-DC converter with reduced passive components size and common mode electro-magnetic interference
A bidirectional AC-DC converter is presented with reduced passive component size and common mode electro-magnetic interference. The converter includes an improved input stage formed by two coupled differential inductors, two coupled common and differential inductors, one differential capacitor and two common mode capacitors. With this input structure, the volume, weight and cost of the input stage can be reduced greatly. Additionally, the input current ripple and common mode electro-magnetic interference can be greatly attenuated, so lower switching frequency can be adopted to achieve higher efficiency.
24 POWER TRANSMISSION AND DISTRIBUTION↗
Improved battery parameter estimation method considering operating scenarios for HEV/EV applications
This study presents an improved battery parameter estimation method based on typical operating scenarios in hybrid electric vehicles and pure electric vehicles. Compared with the conventional estimation methods, the proposed method takes both the constant-current charging and the dynamic driving scenarios into account, and two separate sets of model parameters are estimated through different parts of the pulse-rest test. The model parameters for the constant-charging scenario are estimated from the data in the pulse-charging periods, while the model parameters for the dynamic driving scenario are estimated from the data in the rest periods, and the length of the fitted dataset is determined by the spectrum analysis of the load current. In addition, the unsaturated phenomenon caused by the long-term resistor-capacitor (RC) network is analyzed, and the initial voltage expressions of the RC networks in the fitting functions are improved to ensure a higher model fidelity. Simulation and experiment results validated the feasibility of the developed estimation method.
25 ENERGY STORAGE↗
Wireless power transmission for battery charging
A wireless power transmission system is provided for high power applications. The power transmission system is comprised generally of a charging unit configured to generate an alternating electromagnetic field and a receive unit configured to receive the alternating electromagnetic field from the charging unit. The charging unit includes a power source; an input rectifier; an inverter; and a transmit coil. The transmit coil has a spirangle arrangement segmented into n coil segments with capacitors interconnecting adjacent coil segments. The receive unit includes a receive coil and an output rectifier. The receive coil also has a spirangle arrangement segmented into m coil segments with capacitors interconnecting adjacent coil segments.
24 POWER TRANSMISSION AND DISTRIBUTION↗
A correlation based fault detection method for short circuits in battery packs
Here this paper presents a fault detection method for short circuits based on the correlation coefficient of voltage curves. The proposed method utilizes the direct voltage measurements from the battery cells, and does not require any additional hardware or effort in modeling during fault detection. Moreover, the inherent mathematical properties of the correlation coefficient ensure the robustness of this method as the battery pack ages or is imbalanced in real applications. In order to apply this method online, the recursive moving window correlation coefficient calculation is adopted to maintain the detection sensitivity to faults during operation. An additive square wave is designed to prevent false positive detections when the batteries are at rest. The fault isolation can be achieved by identifying the overlapped cell in the correlation coefficients with fault flags. Simulation and experimental results validated the feasibility and demonstrated the advantages of this method.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗