The Experts below are selected from a list of 13350 Experts worldwide ranked by ideXlab platform
Zhengming Zhao - One of the best experts on this subject based on the ideXlab platform.
-
A Phase Synchronization Technique Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless electric vehicle charging system, when both the primary and secondary converters are active, the Phase synchronization between the two converters are necessary to control the power flow direction. This article proposes a new Phase synchronization method by tracking the maximum (or minimum, depending on the power flow direction) value of the output current, without auxiliary hardware or the real-time communication between the primary and secondary sides. First, the relationship between the output current and the Phase difference of the control signals is derived. It is found that the maximum output current is determined by the Relative Phase-Shift angle (time interval between the middle points of the primary and secondary voltages) and the internal Phase-Shift angles of the two converters (time interval when the output voltage equals to the dc-link voltage). Second, a new scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Third, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Moreover, the relationship between the internal Phase-Shift angle and the transfer power is derived to regulate the magnitude of the transfer power, with the dead-time effect taken into consideration. Finally, experimental results verify the validity of the proposed method with different air gaps and power levels. The method is easy to be implemented, helpful for the optimal operation of the static and quasi-static wireless charging system and suitable for the bidirectional power flow.
-
Phase Synchronization of Control Signals Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless power transfer (BWPT) system, when both the primary and secondary converters become active, the Phase synchronization between their control signals are necessary to control the power flow direction. Generally, the synchronization is realized by the real-time wireless communication devices or the auxiliary windings, which calls for high requirements of the hardware for sampling and controlling as well as increases the cost. Therefore, this paper proposes a new Phase synchronization method without the real-time communication or auxiliary hardware. Firstly, the relationship between the output current and the Phase differences of the control signals is derived. It is found that the extreme value of the output current is determined by the Relative Phase-Shift angle between the primary and secondary converters and the internal Phase-Shift angles of the two converters. Secondly, a scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Thirdly, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Finally, simulation and experimental results verify the validity of the proposed method. The method is easy to be implemented, and useful for the bidirectional power flow of the static BWPT system.
Fang Liu - One of the best experts on this subject based on the ideXlab platform.
-
A Phase Synchronization Technique Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless electric vehicle charging system, when both the primary and secondary converters are active, the Phase synchronization between the two converters are necessary to control the power flow direction. This article proposes a new Phase synchronization method by tracking the maximum (or minimum, depending on the power flow direction) value of the output current, without auxiliary hardware or the real-time communication between the primary and secondary sides. First, the relationship between the output current and the Phase difference of the control signals is derived. It is found that the maximum output current is determined by the Relative Phase-Shift angle (time interval between the middle points of the primary and secondary voltages) and the internal Phase-Shift angles of the two converters (time interval when the output voltage equals to the dc-link voltage). Second, a new scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Third, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Moreover, the relationship between the internal Phase-Shift angle and the transfer power is derived to regulate the magnitude of the transfer power, with the dead-time effect taken into consideration. Finally, experimental results verify the validity of the proposed method with different air gaps and power levels. The method is easy to be implemented, helpful for the optimal operation of the static and quasi-static wireless charging system and suitable for the bidirectional power flow.
-
Phase Synchronization of Control Signals Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless power transfer (BWPT) system, when both the primary and secondary converters become active, the Phase synchronization between their control signals are necessary to control the power flow direction. Generally, the synchronization is realized by the real-time wireless communication devices or the auxiliary windings, which calls for high requirements of the hardware for sampling and controlling as well as increases the cost. Therefore, this paper proposes a new Phase synchronization method without the real-time communication or auxiliary hardware. Firstly, the relationship between the output current and the Phase differences of the control signals is derived. It is found that the extreme value of the output current is determined by the Relative Phase-Shift angle between the primary and secondary converters and the internal Phase-Shift angles of the two converters. Secondly, a scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Thirdly, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Finally, simulation and experimental results verify the validity of the proposed method. The method is easy to be implemented, and useful for the bidirectional power flow of the static BWPT system.
-
Measuring the complex orbital angular momentum spectrum of light with a mode-matching method
Optics letters, 2017Co-Authors: Peng Zhao, Xue Feng, Kaiyu Cui, Fang Liu, Wei Zhang, Yidong HuangAbstract:The Relative Phase Shift among different components in the superposition of orbital angular momentum (OAM) states contains significant information. However, with existing methods of measuring the OAM spectrum, the Phase term of the spectrum coefficient is hard to obtain. In this Letter, a mode-matching method is proposed to identify the complex OAM spectrum with a Mach-Zehnder interferometer and a charge-coupled device camera. It has the potential to extend the applications of OAM in scenarios sensitive to the Phase factor, for instance, in imaging and quantum manipulation. The method is experimentally demonstrated with the superposition of two or three OAM states, while the maximum deviation of the energy ratio and the Relative Phase Shift is 8.4% and 5.5% of 2π, respectively.
M Wax - One of the best experts on this subject based on the ideXlab platform.
-
ICASSP - The estimate of time delay between two signals with random Relative Phase Shift
ICASSP '81. IEEE International Conference on Acoustics Speech and Signal Processing, 1Co-Authors: M WaxAbstract:This paper presents the maximum likelihood estimate of the time delay between two signals with random Relative Phase Shift. The analysis applies for both broad-band and narrowband signals and incorporates a parametric representation of the spread of the Phase variation which allows the examination of all cases ranging from uniformly distributed Phase Shift to known Phase Shift. A realization of the ML estimator is presented which illustrated the difference between optimum processing for random Phase Shift and no Phase Shift. The Cramer-Rao bound is also derived and the performance degradation is discussed.
Chiachan Chang - One of the best experts on this subject based on the ideXlab platform.
-
design of a reflection type Phase Shifter with wide Relative Phase Shift and constant insertion loss
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Shengfuh Chang, Chiachan ChangAbstract:reflection-type Phase Shifter with constant insertion loss over a wide Relative Phase-Shift range is presented. This important feature is attributed to the salient integration of an impedance-transforming quadrature coupler with equalized series-resonated varactors. The impedance-transforming quadrature coupler is used to increase the maximal Relative Phase Shift for a given varactor with a limited capacitance range. When the Phase is tuned, the typical large insertion-loss variation of the Phase Shifter due to the varactor parasitic effect is minimized by shunting the series-resonated varactor with a resistor Rp. A set of closed-form equations for predicting the Relative Phase Shift, insertion loss, and insertion-loss variation with respect to the quadrature coupler and varactor parameters is derived. Three Phase Shifters were implemented with a silicon varactor of a restricted capacitance range of Cv,min = 1.4 pF and Cv,max = 8 pF, wherein the parasitic resistance is close to 2 Omega. The measured insertion-loss variation is 0.1 dB over the Relative Phase-Shift tuning range of 237deg at 2 GHz and the return losses are better than 20 dB, excellently agreeing with the theoretical and simulated results.
Kainan Chen - One of the best experts on this subject based on the ideXlab platform.
-
A Phase Synchronization Technique Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2020Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless electric vehicle charging system, when both the primary and secondary converters are active, the Phase synchronization between the two converters are necessary to control the power flow direction. This article proposes a new Phase synchronization method by tracking the maximum (or minimum, depending on the power flow direction) value of the output current, without auxiliary hardware or the real-time communication between the primary and secondary sides. First, the relationship between the output current and the Phase difference of the control signals is derived. It is found that the maximum output current is determined by the Relative Phase-Shift angle (time interval between the middle points of the primary and secondary voltages) and the internal Phase-Shift angles of the two converters (time interval when the output voltage equals to the dc-link voltage). Second, a new scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Third, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Moreover, the relationship between the internal Phase-Shift angle and the transfer power is derived to regulate the magnitude of the transfer power, with the dead-time effect taken into consideration. Finally, experimental results verify the validity of the proposed method with different air gaps and power levels. The method is easy to be implemented, helpful for the optimal operation of the static and quasi-static wireless charging system and suitable for the bidirectional power flow.
-
Phase Synchronization of Control Signals Based on Perturbation and Observation for Bidirectional Wireless Power Transfer System
2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018Co-Authors: Fang Liu, Kainan Chen, Zhengming ZhaoAbstract:For the bidirectional wireless power transfer (BWPT) system, when both the primary and secondary converters become active, the Phase synchronization between their control signals are necessary to control the power flow direction. Generally, the synchronization is realized by the real-time wireless communication devices or the auxiliary windings, which calls for high requirements of the hardware for sampling and controlling as well as increases the cost. Therefore, this paper proposes a new Phase synchronization method without the real-time communication or auxiliary hardware. Firstly, the relationship between the output current and the Phase differences of the control signals is derived. It is found that the extreme value of the output current is determined by the Relative Phase-Shift angle between the primary and secondary converters and the internal Phase-Shift angles of the two converters. Secondly, a scheme for generating the control signals is proposed to ensure that the Relative Phase-Shift angle is not influenced by the internal Phase-Shift angles. Thirdly, based on the perturbation and observation method, a procedure is proposed to track the extreme value of the output current and obtain the target Relative Phase-Shift angle for the Phase synchronization state. Finally, simulation and experimental results verify the validity of the proposed method. The method is easy to be implemented, and useful for the bidirectional power flow of the static BWPT system.
