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Power Electronics in New and Renewable Energy Systems Mohammad A. Abusara Lecturer in control and Power Electronics Renewable Energy Research Group College of Engineering, Mathematics, and Physical Sciences

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Outline Microgrid Grid Connected Interleaved Inverter Exhaust Heat Energy Recovery Systems Marine Renewable Energy

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Microgrid System

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35kWHr lithium-ion batteries (60kVA Inverter) 100kW micro Gas Turbine

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MicroGrid: Controller Structure

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Microgrid Challenges and Features Challenges Maintain stability during connection, disconnection, load application/shedding Good Load sharing in island mode Good current quality in grid-connected mode Features Seamless transfer from grid-connected mode to island mode and vice versa Improved current quality Improved transient response

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Microgrid-Practical Test

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Microgrid-Practical Results

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The effect of virtual impedance on improving current THD

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Grid Connected Interleaved Inverter

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Interleaved Concept One channel is replaced by a number of channels connected in parallel Switching instants are phase shifted equally over a switching period Introduced for telecommunication power supplies (low voltage high current)

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Interleaved Inverter- Advantages Smaller Power Switches Smaller capacitors Smaller Inductor

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Novel DC/AC Grid Connected Interleaved Inverter Advantages over 2-level topology Smaller C and hence so high output impedance to voltage harmonics (better current THD) No need for a second L Smaller in size

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Controller Structure

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System Modelling

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Passive Damping For active damping Sampling frequency (35kHz) is only 1.47 to 3.2 times the natural resonance frequency Passive damping is possible (small capacitor current thanks to interleaved topology)

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Passive Damping R Root locus, R = 0 ohmRoot locus, R = 0.5 ohm The varying parameter in the Root Locus is the grid impedance

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Controller Design Phase Lag Controller Proportional Controller K(z) =10

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Robust Digital Controller Immunity to Grid Impedance Variations Excellent Current Quality (THD=2.3%)

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Interleaved Grid Connected Inverter

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Exhaust Heat Energy Recovery Systems

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Energy Recovery System Although it is a dominant prime mover and one of the most efficient power sources, a typical modern turbocharged Diesel engine still wastes significant amounts of fuel energy. The exhaust waste heat energy can be recovered and converted into useful electrical power

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Components of Exhaust Recovery System Fuel Saving 5-7% Power Boost 10-15% Turbine + High speed alternatorPower Electronics

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Exhaust Energy Recovery

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Organic Rankin Cycle (ORC) System

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ORC System Diagram

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ORC Optimisation

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Customers On road trucks Off road vehicleStationary power plants

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Hybrid Turbocharger

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Marine Renewable Energy

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Marine Renewable Energy Systems Wave Tide

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Thank You