AC-DC conversion using microgenerator

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DIRECT AC-DC ELECTRONIC CONVERTER TOPOLOGY.

Presented by:Bilal Ahmad. Areez Irfan.Hamza Ahmad.

CONTENTS. Introduction.

Converter Topologies.

Implementation Design.

Simulation Results.

Conventionally power electronic converters have two stages

a. Diode Bridge Rectifiers.

b. DC –DC Converters.

(It is less efficient and cant be used for electromagnetic microgenerators)

INTRODUCTION.

For efficient and maximum energy direct AC-DC power

electronic converter topology is proposed.

The single stage AC to DC power conversion is

achieved by utilizing the bidirectional conduction capability of MOSFETs.

ELECTROMAGNETIC MICROGENERATORS.

There are various microgenerators using different conversion

mechanisms but Electromagnetic microgenerators are common. Due to good power density. And they are typically spring-mass system.

Output:

Typically around few hundred millivolts.

Mechanical en-ergy

Electrical energy Electromagnetic damping

` Power processing stage between transducer and load.

Output has to be processed by power converter to produce suitable DC output voltage.

Amount of energy conversion depends on the damping force.

Damping force can be varied by changing the effective

resistance.

CONVERTER TOPOLOGIES.

A power converter is required for energy-harvesting applications.

Main function of the converter is to condition the AC output of the microgenerator to a suitable DC level and offer an adjustive resistive load to the microgenerator.

Two stage power converter is not used for electromagnetic microgeneration Because :

a) Diode voltages in bridge rectifier are difficult to overcome for low input voltage.

b) Diode losses are increased as input current is much higher than output current.

c) A rectifier offers a nonlinear load, which makes the converter unsuitable for

energy harvesting.

Above disadvantages are eliminated with Direct AC-DC boost converters.

DUAL POLARITY BOOST CONVERTER FOR

DIRECT AC-DC CONVERSION.

PROPOSED DIRECT AC-DC CONVERTER:SPLIT-CAPACITOR TOPOLOGY.

This operation has many advantages:

a) A constant duty cycle extracts constant power from source, enabling a simple control.

b) A converter operating with a constant duty cycle has only fundamental and switching harmonic frequency components and thus offers a resistive load to the microgenerator.

The implementation of auxiliary circuits (gate driver and control circuits) is very important for low power applications. They are chosen in such a way

that they will consume very low power.

Feedback control circuit.

Gate driver circuit.

Startup circuit.

IMPLEMENTATION.

SIMULATION RESULT.

Any Questions