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Power Electronics Society The Power Electronics Society (PEL-35) fosters the development and innovation in power electronics technology on Long Island. This technology includes the application of circuit theory and design techniques, for the efficient conversion, control and condition of electric power. |
App Notes & Articles > Load Sources for Peak Efficiency > Magnetics (Ridley Engineering) LI Power Supply Firms > Behlman LI Power Reps > Link One > TAM Power Semi > EPC > Infineon Power Electronics > 3, Modeling/Losses/Efficiency > 4a, Inclusion of Switching Loss > 11, Discontinuous Conduction > 12a, Magnetics Energy Storage > 17, Line-Commutated Rectifiers > 20, Quasi-Resonant Converters > Ap 2, Magnetics Design Tables > Ap 3, Sw Modeling, CCM SEPIC Reference > iPES > Verimod
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Past Lectures |
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The lectures listed below took place before the annual IEEE LI Power Electronics Symposium. For lectures taking place at the symposium, please visit:
Flyback transformer basics are first explored, followed by a review of losses for these devices. Core losses are determined by several foactors including DC bias and duty cycle. The effect of snubbers on leakage losses is also discussed in addition to the effect of input voltage range on flyback transformer power density.
The operation of GaN devices is discussed, followed by an overview of the state-of-the-art and future of GaN technology. Practical high-efficiency applications are presented including envelope tracking, wireless power transfer, class-D audio amplifier and power conversion. Circuit design considerations are also covered such as gate drive, layout, paralleling, and thermal management.
Attenuating conducted EMI can be complex and difficult, especially when the root cause is not obvious. The lecture begins with the basics of EMI types and categories, followed by coupling mechanisms and measurement standards. Conducted EMI measurements and test setups are also explored. As an illustrative example, the characterization of a simulated Buck converter and a real-world isolated DC/DC converter are examined showing noise origins, paths and characterization. Tips on converter selection to help achieve lower EMI are discussed. Circuit simulations are provided to illustrate insertion loss, followed by methods to determine stability of a given input filter network with a particular DC-DC Converter. In addition to classic passive differential and common-mode filter schemes, active EMI filter topology is also explored. The lecture concludes with discussions on case histories and troubleshooting topics.
Fundamental magnetic theory and the associated equations are first reviewed, covering inductance calculations, Ampere’s law for magnetizing force, Faraday’s law for flux density, BH curves and magnetic saturation. From this point practical design considerations are explored including core loss, AC and DC wire losses, effective permeability, inductance rolloff and winding methods. To help illustrate practical considerations, an in-depth design example of a flyback coupled inductor is provided. Trade-offs among various core materials are also discussed in addition to methods for achieving optimal coupling between the primary and secondary windings.
When developing DC/DC converters and power systems, the slower dynamic speed and higher cost of digital loop control are not suitable for many applications. However, the ability to configure, monitor and control DC/DC converters or power systems through a digital communications interface is of great value. For many applications, an ideal design utilizes an analog PWM controller combined with a microcontroller-based digital power management interface. New technology that integrates an 8-bit microcontroller, high voltage drivers, precision analog and pulse width modulation control into a single device can be ideal for many power electronics applications. This lecture introduces new “Digitally Enhanced Power Analog” technology and provides details into system and applications. Typical applications include configurable point-of-load DC/DC converters, programmable battery chargers, intelligent LED drivers and programmable DC/DC converters with integrated PMBus communication.
While there are many ways to cut weight in airborne/defense electronic systems, the power supply subsystem is an area where major improvement can be realized. In many systems, the AC power source is converted to an intermediate voltage which is distributed and then down-converted as needed via local DC/DC converters. Higher intermediate voltages can be used to lower currents and minimize I2R losses. However, with multiple voltage requirements often spread from <1 V to 28 V with power requirements ranging from a few watts to multi-kilowatts, distribution losses and the multi-stage conversion loss can become unwieldy. This presentation discusses products that offer advantages over conventional technologies, including higher density, higher efficiency, and lighter/lower-noise architectures. Using the Zero Voltage Switching (ZVS) topology this technology achieves a high power/weight ratio which is a crucial factor especially in airborne applications. Also covered are high-efficiency active ripple attenuators that dramatically reduce noise while improving transient load response without the necessity of large output capacitance.
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Interested in presenting an IEEE PELS lecture for Long Island? |
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Providing a lecture for the Long Island IEEE PELS society is an excellent method for reaching out to the power electronics community in this area. If your company or organization is interested in presenting a PELS lecture, please review the following guidelines. |
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2015-11-22 |
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Chair
ieee.li
Vice
Chair
Overlooked Loss Mechanisms In Flyback Transformers
Isaac
Cohen - TI