| 1. |
- Song, Kai, et al.
(författare)
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An Impedance Decoupling-Based Tuning Scheme for Wireless Power Transfer System under Dual-Side Capacitance Drift
- 2021
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Ingår i: IEEE Transactions on Power Electronics. - 0885-8993 .- 1941-0107. ; 36:7, s. 7526-7536
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Tidskriftsartikel (refereegranskat)abstract
- High performance of a wireless power transfer system is related to the resonance. However, the capacitance drift caused by temperature variation leads to detuning. In this article, a tuning scheme against dual-side capacitance drift using the impedance decoupling algorithm is investigated. First, the impact of the capacitance drift on transmission efficiency and output power are analyzed. Second, it is difficult to compensate for the dual-side capacitance drift quickly since the primary and secondary sides are coupled. Therefore, the impedance decoupling algorithm is introduced. The primary and secondary reactances are decoupled from the total impedance. The two independent reactances are only determined by the capacitance drift of the corresponding side. Then, by adjusting system frequency and the phase-shift angle of the semiactive rectifier, the reactances of both sides can be eliminated, respectively. Compared with the existing tuning methods focusing on total input impedance, the continuous adjustment on two sides is avoided, so the tuning time is significantly reduced. The experimental results prove that the proposed method can improve the system efficiency by 5%-40% and reduce the tuning time by 67% under different capacitance drift.
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| 2. |
- Song, Kai, et al.
(författare)
-
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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