The Experts below are selected from a list of 181425 Experts worldwide ranked by ideXlab platform

Naoki Shinohara - One of the best experts on this subject based on the ideXlab platform.

  • A 5.8-GHz Phased Array System Using Power-Variable Phase-Controlled Magnetrons for Wireless Power Transfer
    IEEE Transactions on Microwave Theory and Techniques, 2020
    Co-Authors: Bo Yang, Xiaojie Chen, Jie Chu, Tomohiko Mitani, Naoki Shinohara
    Abstract:

    We build a phased array system with four Power-Variable phase-controlled magnetrons (PCMs) by applying the injection-locking method and phase-locked-loop method. To reduce the cost and ensure the durability of the phased array, a waveguide slot array antenna was designed and used for the output antenna of Power-Variable PCMs. The slot antenna has an expected angle deflection of 22.5°, a gain of 24.9 dBi, and the half bandwidth of the main lobe was 10°. We demonstrated the properties of microwave beamforming and wireless Power transfer based on the magnetron phased array system. In horizontal directions, a beam scanning range of ±3° was obtained by adjusting the output phase of the magnetrons. Furthermore, the received dc Power reaches 142 W at a distance of 5 m when the output microwave Power of the magnetron phased array is 1304 W.

  • Development of a 5.8 GHz Power-Variable phase-controlled magnetron
    2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017
    Co-Authors: Bo Yang, Tomohiko Mitani, Naoki Shinohara
    Abstract:

    In this study, we developed a 5.8 GHz PowerVariable phase-controlled magnetron (PVPCM), which utilizes an injection locking method and phase locked loop (PLL) method. We had developed a PVPCM for a 2.45 GHz oven magnetron and we applied the same method to the 5.8 GHz magnetron. In this method, we control the phase of 5.8 GHz magnetron output by a phase shifter without the anode current control PLL method. Then we can control the output Power of the magnetron by controlling the anode current. Our experiments show that, the developed PVPCM had a 655 W stable output Power, the phase locked response time was less than 50 μs, and the phase-locked stability was lower than ±5°.

David J. Braun - One of the best experts on this subject based on the ideXlab platform.

  • Algorithmic Design of Low-Power Variable-Stiffness Mechanisms
    IEEE Transactions on Robotics, 2017
    Co-Authors: Vincent Chalvet, David J. Braun
    Abstract:

    Compliant actuators enabling low-Power stiffness adaptation are missing ingredients and key enablers of next generation robotic systems. One of the key components of these actuators is the mechanism implementing stiffness adaptation that requires sophisticated control and nontrivial mechanical design. However, despite recent advances in controlling these systems, their design remains experience based and not well understood. In this paper, we present an optimization-based computational framework for the design of intrinsically low-Power compliant Variable stiffness mechanisms. The core ingredient of this framework is the mathematical formulation of the design problem—provided by a constrained nonlinear parameter optimization—which is computationally solved here to identify optimal Variable stiffness designs. We show the basic capability of this formulation in finding parameters for Variable stiffness mechanisms that require the least Power by design. Further, we demonstrate the generality of this method in cross-comparing mechanisms with different kinematic topology to identify the one that requires the least Power by design.

  • Criterion for the Design of Low-Power Variable Stiffness Mechanisms
    IEEE Transactions on Robotics, 2017
    Co-Authors: Vincent Chalvet, David J. Braun
    Abstract:

    Designing robotic systems capable of low-Power operation, inherent to their compliant actuation, has been elusive in practical application. In this paper, we propose a physical measure to mathematically define mechanical designs that are suitable to realize stiffness modulation with low Power cost. Using this measure, we present a mathematical formulation of an ideal Variable stiffness mechanism unaffected by the external load during its operation. We then analyze several existing mechanisms from the literature to relate design features with analytical conditions inherent to low Power stiffness modulation in practical designs. Through this analysis, we identify an approximate practical realization of an ideal actuator capable of stiffness modulation with inherently low Power cost. Similar to a number of existing efficient Variable stiffness mechanisms, this mechanism is able to hold a given stiffness setting with zero input force under no external load. However, unlike many other previously designed mechanisms, it enables infinite range stiffness modulation using finite control forces. A practical Variable stiffness mechanism that is capable of infinite range stiffness modulation using finite control forces leads to lower Power cost and reduced energy consumption.

Bo Yang - One of the best experts on this subject based on the ideXlab platform.

  • A 5.8-GHz Phased Array System Using Power-Variable Phase-Controlled Magnetrons for Wireless Power Transfer
    IEEE Transactions on Microwave Theory and Techniques, 2020
    Co-Authors: Bo Yang, Xiaojie Chen, Jie Chu, Tomohiko Mitani, Naoki Shinohara
    Abstract:

    We build a phased array system with four Power-Variable phase-controlled magnetrons (PCMs) by applying the injection-locking method and phase-locked-loop method. To reduce the cost and ensure the durability of the phased array, a waveguide slot array antenna was designed and used for the output antenna of Power-Variable PCMs. The slot antenna has an expected angle deflection of 22.5°, a gain of 24.9 dBi, and the half bandwidth of the main lobe was 10°. We demonstrated the properties of microwave beamforming and wireless Power transfer based on the magnetron phased array system. In horizontal directions, a beam scanning range of ±3° was obtained by adjusting the output phase of the magnetrons. Furthermore, the received dc Power reaches 142 W at a distance of 5 m when the output microwave Power of the magnetron phased array is 1304 W.

  • Development of a 5.8 GHz Power-Variable phase-controlled magnetron
    2017 Eighteenth International Vacuum Electronics Conference (IVEC), 2017
    Co-Authors: Bo Yang, Tomohiko Mitani, Naoki Shinohara
    Abstract:

    In this study, we developed a 5.8 GHz PowerVariable phase-controlled magnetron (PVPCM), which utilizes an injection locking method and phase locked loop (PLL) method. We had developed a PVPCM for a 2.45 GHz oven magnetron and we applied the same method to the 5.8 GHz magnetron. In this method, we control the phase of 5.8 GHz magnetron output by a phase shifter without the anode current control PLL method. Then we can control the output Power of the magnetron by controlling the anode current. Our experiments show that, the developed PVPCM had a 655 W stable output Power, the phase locked response time was less than 50 μs, and the phase-locked stability was lower than ±5°.

Vincent Chalvet - One of the best experts on this subject based on the ideXlab platform.

  • Algorithmic Design of Low-Power Variable-Stiffness Mechanisms
    IEEE Transactions on Robotics, 2017
    Co-Authors: Vincent Chalvet, David J. Braun
    Abstract:

    Compliant actuators enabling low-Power stiffness adaptation are missing ingredients and key enablers of next generation robotic systems. One of the key components of these actuators is the mechanism implementing stiffness adaptation that requires sophisticated control and nontrivial mechanical design. However, despite recent advances in controlling these systems, their design remains experience based and not well understood. In this paper, we present an optimization-based computational framework for the design of intrinsically low-Power compliant Variable stiffness mechanisms. The core ingredient of this framework is the mathematical formulation of the design problem—provided by a constrained nonlinear parameter optimization—which is computationally solved here to identify optimal Variable stiffness designs. We show the basic capability of this formulation in finding parameters for Variable stiffness mechanisms that require the least Power by design. Further, we demonstrate the generality of this method in cross-comparing mechanisms with different kinematic topology to identify the one that requires the least Power by design.

  • Criterion for the Design of Low-Power Variable Stiffness Mechanisms
    IEEE Transactions on Robotics, 2017
    Co-Authors: Vincent Chalvet, David J. Braun
    Abstract:

    Designing robotic systems capable of low-Power operation, inherent to their compliant actuation, has been elusive in practical application. In this paper, we propose a physical measure to mathematically define mechanical designs that are suitable to realize stiffness modulation with low Power cost. Using this measure, we present a mathematical formulation of an ideal Variable stiffness mechanism unaffected by the external load during its operation. We then analyze several existing mechanisms from the literature to relate design features with analytical conditions inherent to low Power stiffness modulation in practical designs. Through this analysis, we identify an approximate practical realization of an ideal actuator capable of stiffness modulation with inherently low Power cost. Similar to a number of existing efficient Variable stiffness mechanisms, this mechanism is able to hold a given stiffness setting with zero input force under no external load. However, unlike many other previously designed mechanisms, it enables infinite range stiffness modulation using finite control forces. A practical Variable stiffness mechanism that is capable of infinite range stiffness modulation using finite control forces leads to lower Power cost and reduced energy consumption.

Richard Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Test-bench for very high Power Variable frequency drives working under constrained grid conditions
    2013 IEEE Energy Conversion Congress and Exposition, 2013
    Co-Authors: Stefan Schröder, Jie Shen, Fan Zhang, Kunlun Chen, Laigui Qin, Richard Zhang
    Abstract:

    This paper introduces a test-bench concept for high Power Variable frequency drives that can work reliably also with a weak and Power limited grid. Experimental results are shown for a 10MW+ drive test bench with only a remote 1.25MVA feeding transformer supply. Common “pump-back” configurations circulate the test bench Power via the supply grid. This produces huge distortions and potential instabilities with weak grids. Hence, we circulate the Power via a virtual 50 or 60 Hz grid that is not connected to the feeding grid. Only the losses are fed from the grid directly to the dc-link of one test-bench VFD via a simple diode rectifier. Since the total system losses are typically only about 10% of the rated Powers, the corresponding grid disturbances are significantly reduced. The implemented test-bench is utilizing a virtual machine but the concept can also be combined with a real motor-generator set.