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This paper analyzes the behavior of a pure capacitive output filter in parallel and series-parallel resonant converters. Unlike traditional resonant voltage-and current-driven rectifiers, pure capacitive output filters present interruptions in power transfer from the transformer primary to the secondary, owing to the existence of a parallel resonant capacitor. Therefore, existing formulas for different...
Single-phase AC/DC or DC/AC systems inherently subject to harmonic disturbance which is caused by the well-known double line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc-link, but such passive filtering approach may inevitably lead to low power density and limited system lifetime. An alternative approach is to use active power...
The impact of the shield resistance (Rsh) on the waveform ringing and system efficiency is assessed in this work for 30V trench power FETs with shielded-gate (TP-FETs). Two different approaches, named distributed and local Rsh, are extensively investigated by experimental and numerical simulation tools. A layout distributed Rsh emerges as the ultimate solution to maximize the self-damping without...
With voltage-balancing control, the voltage difference among sub-module (SM) capacitors in a modular multilevel converter can be reduced. However, this comes at the cost of increased device switching frequency. In this paper, the relationship between the switching frequency and SM capacitor unbalanced voltage is investigated. As the relationship depends on the voltage-balancing control schemes, a...
Transformer parameters such as leakage inductance and self-capacitance are rarely calculated in advance during the design phase, because of the complexity and huge analytical error margins caused by practical winding implementation issues. Thus, choosing one transformer architecture over another for a given design is usually based on experience or a trial and error approach. This work presents equations...
LLC Resonant converters have been popular in recent years by providing highly-efficient, compact isolated power conversion for numerous applications. 48V to 12V and 400V to 12V step-down isolated converters are often required in server, telecom and automotive applications. While the switching losses in LLC converters are eliminated due to zero-voltage switching, the primary-side switch output capacitance...
There is a current movement within the scientific, engineering, educational and entrepreneurial communities called “making.” Most electronics makers are familiar with hardware offerings Arduino™ and Xbee™, which are user friendly rapid prototyping platforms for microcontrollers and wireless networks respectively; however an equivalent solution for power electronics is not available at comparable cost...
In this paper, the common mode (CM) EMI noise characteristic of three popular topologies of resonant converter (LLC, CLL and LCL) is analyzed. The comparison of their EMI performance is provided. A state-of-art LLC resonant converter with matrix transformer is used as an example to further illustrate the CM noise problem of resonant converters. The CM noise model of LLC resonant converter is provided...
This paper presents a new strategy, diffusion charge redistribution (DCR), for balancing power among photovoltaic cells to increase energy extraction and to improve maximum power point tracking (MPPT) efficiency under partial shading conditions. With DCR, testing and binning during cell manufacturing can be eliminated, and significant cost savings can be achieved during production. The proposed technique...
Bearing currents cause a reduction of ball bearing's lifetime in electronically commutated permanent magnet motors. To compensate the lifetime decreasing factors, a tradeoff between special bearings and additional changes in the machine design have to be found. Stator grounding, for example, keeps the bearing voltage low and thus guarantees a long fan system's lifetime, however, results in a higher...
In this paper, a current-fed asymmetric full-bridge LLCC resonant converter is proposed for the dielectric barrier discharge (DBD) applied to the surface treatment. Compared with a previous design, the asymmetric structure with no front-end buck circuit and only two reverse-voltage blocking diodes is adopted to reduce the component count and circuit complexity. Moreover, the phase-shift control of...
GaN HEMT devices exhibit improved performance in terms of switching speed and reduced on-state resistance, especially if low-voltage and high-frequency conditions are considered. In this paper, a high-power density quasi-resonant converter is proposed in order to improve both the maximum output power and the maximum operating frequency with GaN HEMT devices. Since the proposed converter operates as...
This paper discusses a development for high output of 2.5 MHz inverter without fast-switching semiconductor switches. This inverter consists of a multi-phase inverter using conventional silicon semiconductor switches and multiple core transformers. In this paper, a principle of drop in inverter output voltage which reduces the inverter output voltage due to a relationship between dead-time and a leakage...
This paper extends the Universal Serial Bus (USB) standard to the contactless domain by combining bidirectional data communication with a capacitive power transfer interface. This work first addresses the power transfer with analysis, simulations, and experiment, based on a secondary side phase feedback series resonant topology. This gives the advantage of simple circuitry to regulate output voltage...
Conventional AC-DC driver circuits for Light-Emitting Diode (LED) lamps require large output capacitance across the LED load to minimize the low frequency current ripple. This large capacitance is usually achieved by using an electrolytic capacitor, which has a lifetime that is at least two times less than that of a LED device. To match the potential lifetime of the LEDs, a new isolated single switch...
This paper presents design and implementation of the phase-shift burst-mode control method for interleaved self-oscillating resonant SEPIC converters for LED lighting applications. The proposed control method utilizes delays in the turn-on and turn-off of the power stage and control circuitry in order to reduce requirements for the comparator in the regulation circuit. The control method is experimentally...
Flyback converters are widely used in several applications, however, with this topology it is very challenging to achieve high voltage operation especially with very high step-up ratio (>500) within limited space. This paper presents a new flyback-based topology which utilizes primary parallel and secondary series transformer connection in order to achieve very high step-up ratio (up to 650) as...
The 15 kV SiC N-IGBT is the state-of-the-art high voltage power semiconductor device developed by Cree. The SiC IGBT is exposed to a peak stress of 10–11 kV in power converter systems, with punch-through turn-on dv/dt over 100 kV/μs and turn-off dv/dt about 35 kV/μs. Such high dv/dt requires ultralow coupling capacitance in the dc-dc isolation stage of the gate driver for maintaining fidelity of the...
A new GaAs power switching device, the gFET™ switch was introduced at APEC 2013. This paper describes devices developed since APEC 2013 including depletion mode devices with nominal on resistances of 7, 14 and 40 MΩ as well as an enhancement mode device with a nominal on resistance of 40 MΩ. The enhancement mode device is particularly well suited for use as a control switch in buck converters. The...
Gallium nitride (GaN) based power devices are becoming common place due to their ability to achieve higher efficiencies and higher switching frequencies than is possible with silicon (Si) power MOSFETs. With discrete eGaN® FETs capable of switching at slew rates beyond 40V/ns, the system performance is greatly impacted by aspects outside the power devices, such as high speed gate drivers and printed...
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