Showing papers by "Shoji Otaka published in 2014"
16 Mar 2014
TL;DR: In this paper, a novel control method for wireless power transmission (WPT) is presented, which can maximize the power efficiency only by controlling the voltage ratio between the primary and the secondary side.
Abstract: This paper presents a novel control method for wireless power transmission (WPT). The proposed method can maximize the power efficiency only by controlling the voltage ratio between the primary and the secondary side. Experimental measurement results of the prototype system with 3 kW power transmission show the efficiency difference between the proposed control method and the available maximum value is less than 0.3 % even with a large variation of coil-to-coil distance and load voltage. The automatic controller for the proposed method provides the load-following operation, maintaining both constant power and high efficiency, using a WLAN connection.
33 citations
Patent•
11 Mar 2014TL;DR: In this paper, a foreign object detection device has been used to detect a non-contact foreign object when a power receiver receives power from a power transmitter in a noncontact manner, the foreign object detector being arranged between the power receiver and the power transmitter.
Abstract: A foreign object detection device has a foreign object detector configured to detect a foreign object when a power receiver receives power from a power transmitter in a non-contact manner, the foreign object detector being arranged between the power receiver and the power transmitter, and a power control signal generator configured to generate a power control signal which controls the power transmitted from the power transmitter when the foreign object is detected by the foreign object detector.
13 citations
Patent•
28 Feb 2014TL;DR: In this article, a power receiver including a first rectifying circuit, a second rectifier, a connecting part, and a controller is provided, and the controller performs a control such that the first AC power generating device and the second AC power generator do not operate simultaneously.
Abstract: According to an embodiment, there is provided a power receiver including: a first rectifying circuit, a second rectifying circuit, a connecting part and a controller. The first rectifying circuit rectifies a first AC power generated by a first AC power generating device. The second rectifying circuit rectifies a second AC power generated by a second AC power generating device. The connecting part electrically connects an output terminal of the first rectifying circuit and an output terminal of the second rectifying circuit, in parallel. The controller performs a control such that the first AC power generating device and the second AC power generating device do not operate simultaneously.
6 citations
Patent•
22 May 2014TL;DR: In this paper, the authors provided a wireless power transmission controller in which the input device receives first power information from a power transmitting device, indicating electric power transmitted by the power transmitting devices, and second power information received by a power receiving device.
Abstract: There is provided a wireless power transmission controller in which the input device receives first power information from a power transmitting device, indicating electric power transmitted by the power transmitting device, and second power information from a power receiving device, indicating electric power received by the power receiving device, the output device outputs a first control signal instructing a transmission voltage of the power transmitting device, and a second control signal instructing an impedance of the power receiving device, the control device performs raising control of transmission power of the power transmitting device by generating the second control signal so that a difference between the first and second power information becomes small, and generates the first control signal so that a difference between the first power information and a first target value or a difference between the second power information and a second target value becomes small.
3 citations
Patent•
03 Dec 2014
TL;DR: In this article, the authors propose a controller that can estimate the power transmission efficiency between a power transmission unit and a power reception unit by comparing a first voltage detected at a first point in the transmission unit with a second voltage detected in the reception unit.
Abstract: PROBLEM TO BE SOLVED: To provide a controller capable of easily estimating power transmission efficiency.SOLUTION: A controller according to an embodiment of the invention estimates the power transmission efficiency between a power transmission unit which includes a first coil and a first capacity connected in parallel/series to the first coil, and a power reception unit that includes a second coil and a second capacity connected in parallel/series to the second coil and receives the power from the power transmission unit via the connection between the first coil and the second coil. The controller has an estimation section that estimates the power transmission efficiency by comparing a first voltage detected at a first point in the power transmission unit and a second voltage detected at a second point in the power reception unit, or by comparing a first current detected at the first point in the power transmission unit and a second current detected at the second point in the power reception unit.
Patent•
22 Apr 2014TL;DR: In this paper, the level shifter adjusts a voltage level between a first terminal and a second terminal, and switches selectively connect the third terminal of the regulator to a second potential.
Abstract: According to an embodiment, a semiconductor integrated circuit includes a regulator, a level shifter and a switch circuit. The regulator converts an input voltage that is a difference in potential between a first terminal and a third terminal into an output voltage that is a difference in potential between a second terminal and the third terminal. The level shifter adjusts a voltage level between a first terminal and a second terminal. The switch circuit includes a first switch selectively connecting the third terminal of the regulator to a first potential, a second switch selectively connecting the third terminal of the regulator to the first terminal of the level shifter, and a third switch selectively connecting the third terminal of the regulator to a second potential.