The many different techniques for maximum power point tracking of photovoltaic (PV) arrays are discussed. The techniques are taken from the literature dating back to the earliest methods. It is shown that at least 19 distinct methods have been introduced in the literature, with many variations on implementation. This paper should serve as a convenient reference for future work in PV power generation.

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Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques

Wireless power transfer (WPT) using magnetic resonance is the technology which could set human free from the annoying wires. In fact, the WPT adopts the same basic theory which has already been developed for at least 30 years with the term inductive power transfer. WPT technology is developing rapidly in recent years. At kilowatts power level, the transfer distance increases from several millimeters to several hundred millimeters with a grid to load efficiency above 90%. The advances make the WPT very attractive to the electric vehicle (EV) charging applications in both stationary and dynamic charging scenarios. This paper reviewed the technologies in the WPT area applicable to EV wireless charging. By introducing WPT in EVs, the obstacles of charging time, range, and cost can be easily mitigated. Battery technology is no longer relevant in the mass market penetration of EVs. It is hoped that researchers could be encouraged by the state-of-the-art achievements, and push forward the further development of WPT as well as the expansion of EV.

Wireless Power Transfer for Electric Vehicle Applications

This paper overviews theoretical and practical design issues related to inductive power transfer systems and verifies the developed theory using a practical electric vehicle battery charger. The design focuses on the necessary approaches to ensure power transfer over the complete operating range of the system. As such, a new approach to the design of the primary resonant circuit is proposed, whereby deviations from design expectations due to phase or frequency shift are minimized. Of particular interest are systems that are neither loosely nor tightly coupled. The developed solution depends on the selected primary and secondary resonant topologies, the magnetic coupling coefficient, and the secondary quality factor.

Design considerations for a contactless electric vehicle battery charger

A system and method for variable power transfer in an inductive charging or power system. In accordance with an embodiment the system comprises a pad or similar base unit that contains a primary, which creates an alternating magnetic field. A receiver comprises a means for receiving the energy from the alternating magnetic field from the pad and transferring it to a mobile device, battery, or other device. In accordance with various embodiments, additional features can be incorporated into the system to provide greater power transfer efficiency, and to allow the system to be easily modified for applications that have different power requirements. These include variations in the material used to manufacture the primary and/or the receiver coils; modified circuit designs to be used on the primary and/or receiver side; and additional circuits and components that perform specialized tasks, such as mobile device or battery identification, and automatic voltage or power-setting for different devices or batteries.

System and method for inductive charging of portable devices

Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics. A new MPPT system has been developed, consisting of a buck-type DC/DC converter, which is controlled by a microcontroller-based unit. The main difference between the method used in the proposed MPPT system and other techniques used in the past is that the PV array output power is used to directly control the DC/DC converter, thus reducing the complexity of the system. The resulting system has high-efficiency, lower-cost and can be easily modified to handle more energy sources (e.g., wind-generators). The experimental results show that the use of the proposed MPPT control increases the PV output power by as much as 15% compared to the case where the DC/DC converter duty cycle is set such that the PV array produces the maximum power at 1 kW/m/sup 2/ and 25/spl deg/C.

/pdf/development-of-a-microcontroller-based-photovoltaic-maximum-1r79o424xa.pdf

Development of a microcontroller-based, photovoltaic maximum power point tracking control system

Interruption of the Output Voltage in Ferroresonant Circuits

https://www.jstage.jst.go.jp/article/ieejpes1972/105/7/105_7_620/_pdf

Analysis of magnetic frequency tripler by describing function method

To reduce the size and weight of a switching dc-dc converter, it is effective to increase its switching frequency. This requires the reduction of the switching time and switching loss. This paper introduces a dc-dc converter with a short turn-off time and a high efficiency at a switching frequency up to the order of megahertz. This is achieved by using a bipolar transistor with current feedback and core saturation. The turn-off mechanism was analyzed by using an equivalent circuit. The turn-off time was found to be considerably shortened by the quick discharge of the excess carrier in the base region. This is due to the formation of an LC circuit consisting of the saturated inductance of the current feedback transformer which magnetically saturates during the turn-off period, and the base-emitter capacitance of the switching transistor. This phenomenon can be used widely for high-speed and high current switchings.

High‐speed switching of the power transistor in a DC‐DC converter with current feedback and core saturation

The collector voltage surge in the free-running transistor inverter is investigated. In the period of commutation, the collector-emitter voltage increases sharply with a reduction in m.m.f. of the core. This surge is undesirable from the viewpoint of the reliability of transistor and the efficiency. However, since this surge makes the other transistor turn on, this phenomenon is unavoidable. The mechanism of the surge generation is unknown, so we analyze the surge voltage by using a high-frequency equivalent circuit (pi model) of transistor.

Koosuke Harada

Papers

Interruption of the Output Voltage in Ferroresonant Circuits

Analysis of magnetic frequency tripler by describing function method

High‐speed switching of the power transistor in a DC‐DC converter with current feedback and core saturation

Analysis of Voltage Surge in the Free-Running Transistor Inverter

Three-phase Uninterruptible Power Supply Using a Stand-by Inverter of a Single Phase