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This paper presents a new circuit topology of active edge resonant snubbers assisted half-bridge soft switching PWM inverter type high power dc-dc converter for photovoltaic applications. The proposed step-up DC/DC converters with transformer isolation can obtain high voltage step-up trough turns ratio. The proposed dc-dc power converter is composed of typical voltage source-fed half-bridge high frequency...
To integrate distributed generators (DGs) with the power grid, interfacing power converters such as voltage source converters (VSCs) are required. However, due to the switching natures, these converters generate harmonics, which may have detrimental effects on the system. To find out how these harmonics may interact with the grid, it is essential to find the admittance matrices of the converters....
Today's PV micro-inverters (MIVs) provide a modular solution for generation, however the energy storage architectures remain centralized, requiring an additional bi-directional ac-dc converter, with complex cell balancing circuits. Distributing storage capacity within the smart PV panels allows power fluctuations to be locally buffered, while minimizing the need for additional power electronics and...
The analysis of discontinuous conduction mode (DCM) for a novel single active switch based zero voltage and zero current switching (ZVZCS) tapped boost converter is proposed in this paper. The ZVZCS converter includes a lossless snubber composed of three diodes and two capacitors, and exhibits novel ZVZCS operation for wide operating ranges of duty cycle, load current, and input voltage. The voltage...
Frequency controlled Inductive Power Transfer (IPT) systems for Electric Vehicle (EV) battery charging applications often suffer from high power losses in partial-load, because the transmitter coil current is not significantly reduced at low output power. Therefore, in this paper a novel control method is presented that exhibits a substantially higher partial-load efficiency, while it also enables...
In order to prevent the failure of regeneration and reduce energy consumption, making full use of regenerative energy has been widely recognized as an important issue by Chinese urban railway transportation community. This paper provides an overview on the technologies of regenerative energy braking in China. It is first explained that why the ground resistor is popular in China in order to prevent...
An appropriate driver-assistance in order to use regenerative braking effectively is significant as a feasible method of a smart power management for energy-saving and economical solutions in sustainable electric railway operation. It is substantially significant to suppress braking force in high speed so that the braking force is less than corresponding traction force in the field-weakening speed...
DC power distribution can be more effective than AC power distribution in the built environment. However, DC bus protection by using DC circuit breaker (CB) can be costly. This paper proposes a protection method which adopts power electronic-based methods to isolate the faulted segment instead of using CBs. Starting with investigations on the architecture of DC power distribution system for typical...
Encompassing the global developments towards more sustainable and environment-friendly energy solutions for the future, Norway has been developing its own Smart Grid strategy. This strategy follows a path defined by the specific characteristics of the Norwegian energy system and the societal context. This article presents the Norwegian Smart Grid case by collecting the experiences and actions taken...
This paper presents the possibility to make the dc current ripple to zero. The simulation results show that the ripple-less operation is possible theoretically. The fast response in the current control is also shown by using the simple digital control algorithm. The control for the load change is investigated in simulation. The simulation results show that the output current loop is more suitable...
For the sustainable development of our highly electrified societies, power electronics technology is playing an important role. Especially in the field of electric power systems, it is considered as one of the essential technologies which make power grids more efficient, more reliable and more environment-friendly. Those are the goals of so-called smart grids. In this paper, expected roles and applications...
Due to the inherent variability of Renewable Energy Generation Systems (REGSs), REGSs are commonly uncontrollable. Although microgrids can effectively monitor REGSs, it cannot directly manage and control the intermittent output characteristic of REGSs. Recently, many experts recommend that Energy Storage Systems (ESSs) should be integrated into REGSs to mitigate the instability and further reduce...
Inductive power transfer (IPT) systems are resonant converters whose output characteristics are mostly load dependent. Conditions for ensuring a load-independent voltage-transfer ratio of an IPT system have been studied. However, load-independent current output can be more desirable for applications such as battery charging and LED driving. This paper studies the characteristics of IPT systems operating...
This research developed an eccentric disk and novel circular Halbach array to harvest wave energy from the rolling motion of a ship. The designed eccentric disk revolves in a motion that mimics a hula-hoop at higher angular speeds than eccentric disks oscillate normally having. The produced kinetic energy was converted into electrical energy through electromagnetic induction. To enhance electromagnetic...
Winding layouts for the bearingless ac homopolar and consequent pole motors that allow the same coils to be used for both radial force and torque production are investigated. This concept enables a “pure” bearingless motor where the same iron and copper are used for both magnetic bearing operation and torque production. For three phase windings, it is shown that these schemes limit 6-pole machines...
The contactless power transformer systems (CPTs) have recently attracted much attention as it is possible to supply electrical energy to mobile vehicles without cables. 300kW class CPT systems are required for railway vehicles power feeding applications. In this power range, there are some technical problems such as higher reactive power due to longer gap and power control at the misalignment of ground...
This paper proposes a new interleaved current-fed resonant converter with significantly reduced high current output filter which is suitable for EV and HEV applications. The proposed interleaved converter has theoretically zero output filter capacitance, low input current ripple, ZCS turn on and off for all switches and diodes and zero di/dt at turn off of diodes when operated at load independent...
This paper describes mathematical modeling of a novel wound-field synchronous motor self-excited by space harmonics. The torque equation on the dq-reference frame is investigated to clarify the self-excitation mechanism of the proposed motor. It has been analytically explicated how the motor parameters give influences on the self-excited electromagnet torque. Furthermore, the current phase vs. torque...
For power transfer to the rotor circuit of excitation-type synchronous motors, we propose a contactless power transfer system with a primary series capacitor (S topology) to compensate for the leakage reactance. This system does not contain secondary resonant and smoothing capacitors and can reduce the number of components in the rotor circuit. The value of the primary resonant capacitor is determined...
In the Tokaido Shinkansen, we built new Electronic Frequency Converter (EFC) to replace Rotary Frequency Changer. The new EFC is individually operated in basic feeding pattern, and there appears the necessity for over-current tolerance in the converters. We describe the application of EFC to the Shinkansen railyard in this paper, showing the development of the control scheme which can control the...
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