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ELG 4135 :Electronics III Fall 2006 Voltage Filters Analysis, design and implementation of active filters in DC power supplies Presented to : Dr.R.Habash Presented by: Alaa Farhat Mohammed Al-Hashmi Mubarak Al-Subaie November , 24. 2006. Outline. Brief Overview of Filters
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ELG 4135 :Electronics IIIFall 2006 Voltage FiltersAnalysis, design and implementation of active filters in DC power suppliesPresented to :Dr.R.HabashPresented by:Alaa FarhatMohammed Al-HashmiMubarak Al-SubaieNovember , 24. 2006
Outline • Brief Overview of Filters • DC Power Supply System • Filter Types and Classification • Passive Low Pass Filter Circuits • Drawbacks • Proposed Solution • Simulation Results • Improvements • Future Work • References
A Brief Overview of Filters In General • An electrical filter is a device designed to separate, pass or suppress a group of signals from a mixture of signals. • Electrical filters may be classified in a number of ways -Technology -Transfer function -Topology
Original, half-wave rectified, and full-wave rectified signals. (Top to bottom)
Actual Response Passive Low Pass Filter Frequency Response • Ideal Response
Used DC Voltage Filter Circuits • Simple Capacitor Filter • RC Capacitor-Input Filter - Negative gain • LC Capacitor-Input Filter -Not favored in electronics
Problems • Magnitude attenuation • Maximum gain <1 • Requires a DC-DC converter • Pass band must be greater than cutoff frequency • Fixed cutoff frequency
The need for an alternative • New technologies using existing power lines to transmit data over different frequencies -PLC (Power Line Communication) -PLT (Power Line Telecommunication) -PLN (Power Line Networking)
Solution • Active filter type - Eliminate attenuation - Allow a positive gain • Band Pass filter - Allow frequency selection • Higher order filter - Higher quality factor
Band Pass Filter Design • C = C1 = C2 • k = 2 π fo C • R2 = Q/(A.k) • R3 = Q/(2Q^2 – A).k • R1 = 2Q/k
Improvements • Unity gain • Highly selective frequency tuned to 60 Hz by design Tuning: • Gain can be adjusted by adjusting R2 • F0 can be shifted by adjusting R1
Future Work • Implement a circuit with multiple outputs (High, low, and band pass) • Use as a common filter for other applications next to serving role in power supply
References • [1] Phelps, T. K., and W. S. Tate. Passive Input Filter Design, Proceedings of the Sixth National Solid-State Power Conversion Conference, (PowerCon 6), Miami Beach, FL, May 1979. • [2] Sedra, S, and Smith, C, Microelectronic Circuits, Fifth Edition, Oxford, New York - 2004, pp. 171-190.