Elements of Wireless Power Transfer Essential to High Power Charging of Heavy Duty Vehicles

Miller, John M.; Daga, Andrew

doi:10.1109/tte.2015.2426500

Cited by 116 publications

(42 citation statements)

References 29 publications

(54 reference statements)

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“…However, the output voltage gain (G = ⁄ , Vin is the DC input voltage of the inverter) was maintained at about 3.04 across the misalignment range up to 200 mm, which coincides well with the simulation result in Figure 4c. The DC output voltage Vb after the rectifier and the smoothing capacitor (Figure 3a) is the rectifier input RMS voltage V2 multiplied by a constant value, specifically: V2 = √ Vb [12]. The theoretical peak-peak voltage gain is 4.0 ( Figure 4c); hence the theoretical DC output voltage over DC input is 3.27, which is quite close to the measured gain.…”

Section: Experimental Results With Misalignment Under a Constant Air Gapsupporting

confidence: 65%

“…However, this causes the circulating current for resonant control to be quite high. In some studies, soft switching techniques are used to minimize the power losses of switching devices where the phase angle is forced to shift to a small value, making the WPT under-coupled [1,8,[10][11][12]. There are several different ways to provide resonant frequency control, such as adding auxiliary components to adapt to the variance of magnetic couplings and directly switching the frequency of gate signals.…”

Section: Open Accessmentioning

confidence: 99%

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A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

2015

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Abstract:The efficiency of wireless power transfer is sensitive to the horizontal and vertical distances between the transmitter and receiver coils due to the magnetic coupling change. To address the output voltage variation and efficiency drop caused by misalignment, a uniform voltage gain frequency control is implemented to improve the power delivery and efficiency of wireless power transfer under misalignment. The frequency is tuned according to the amplitude and phase-frequency characteristics of coupling variations in order to maintain a uniform output voltage in the receiver coil. Experimental comparison of three control methods, including fixed frequency control, resonant frequency control, and the proposed uniform gain control was conducted and demonstrated that the uniform voltage gain control is the most robust method for managing misalignment in wireless charging applications.

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Section: Experimental Results With Misalignment Under a Constant Air Gapsupporting

confidence: 65%

Section: Open Accessmentioning

confidence: 99%

A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

2015

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“…For eliminating the 5% tolerance in C 1 , the potentiometer R 1 which is adjustable is employed. The four quadrant analog multiplier MLT04 is employed to realize the multiplication of Equation (16). The butterworth low pass filter is designed to filter out the second-order harmonic components shown in Equation (16), and the cut off frequency of the filter is 80 Hz.…”

Section: Current Decompositionmentioning

confidence: 99%

“…In order to meet the requirements of high-power applications, e.g., the power supplying for high-speed trains, the charging system for public vehicles [15][16][17], quite a few methods have been proposed to increase the capacity of IPT systems in the past decade. They can be roughly classified into three categories: the cascaded method, the parallel connected method and the magnetic field enhancement method.…”

Section: Introductionmentioning

confidence: 99%

Circulating Current Reduction Strategy for Parallel-Connected Inverters Based IPT Systems

Liwen

Lin

et al. 2017

Energies

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Multiple inverters connected in parallel is a promising method to upgrade the power capacity of inductive power transfer (IPT) systems. Due to a slight unbalance of the control signals, the inner resistances of the inverters and other uncertainties, circulating currents exist among the parallel units which reduce the reliability of IPT systems. Firstly, the series-parallel resonant tank is employed in the multiple inverters based IPT system to eliminate the DC and harmonic circulating currents. The fundamental circulating currents in the paralleled inverter units are analyzed in detail. Then, for eliminating the fundamental circulating currents, a current decomposition method and a control diagram are proposed to avoid acquiring the phase of the current by detecting zero cross current point which increases the accuracy of the control algorithm. Finally, a 1-kW parallel-connected inverter IPT system is provided to verify the proposed approach. The experimental results show that the proposed method is effective for eliminating the fundamental circulating currents. The maximum efficiency of the system is up to 92.18% which is 0.53% higher compared to that without the current phasor control (91.65%).

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“…SAE J2954 recommends 85 kHz for wireless charging EV batteries [12]; ORNL's (Oak Ridge National Laboratory) experimental setup adopts 22 kHz [5], and in [13], the resonant frequency is 1 MHz, both with kilowatt-level output power. Higher resonant frequency settings can be found in [14,15].…”

Section: Effect Of the Resonant Frequencymentioning

confidence: 99%

Design Method for the Coil-System and the Soft Switching Technology for High-Frequency and High-Efficiency Wireless Power Transfer Systems

Liu

Wang

et al. 2017

Energies

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Abstract:Increasing the resonant frequency of a wireless power transfer (WPT) system effectively improves the power transfer efficiency between the transmit and the receive coils but significantly limits the power transfer capacity with the same coils. Therefore, this paper proposes a coil design method for a series-series (SS) compensated WPT system which can power up the same load with the same DC input voltage & current but with increased resonant frequency. For WPT systems with higher resonant frequencies, a new method of realizing soft-switching by tuning driving frequency is proposed which does not need to change any hardware in the WPT system and can effectively reduce switching losses generated in the inverter. Eighty-five kHz, 200 kHz and 500 kHz WPT systems are built up to validate the proposed methods. Experimental results show that all these three WPT systems can deliver around 3.3 kW power to the same load (15 Ω) with 200 V input voltage and 20 A input current as expected and achieve more than 85% coil-system efficiency and 79% system overall efficiency. With the soft-switching technique, inverter efficiency can be improved from 81.91% to 98.60% in the 500 kHz WPT system.

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Elements of Wireless Power Transfer Essential to High Power Charging of Heavy Duty Vehicles

Cited by 116 publications

References 29 publications

A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

A Uniform Voltage Gain Control for Alignment Robustness in Wireless EV Charging

Circulating Current Reduction Strategy for Parallel-Connected Inverters Based IPT Systems

Design Method for the Coil-System and the Soft Switching Technology for High-Frequency and High-Efficiency Wireless Power Transfer Systems

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