This document summarizes a presentation about direct AC-DC electronic converter topologies for electromagnetic microgenerators. In 3 sentences: Conventionally, power converters have two stages including rectifiers and DC-DC converters, but this is inefficient for microgenerators with low input voltages. The presentation proposes a single-stage direct AC-DC converter using MOSFETs for bidirectional conduction to efficiently convert the AC output of electromagnetic microgenerators into a suitable DC level. It describes a split-capacitor boost converter topology for direct AC-DC conversion that enables constant power extraction from the source using a constant duty cycle for simple control.

2. ALLPPT.com _ Free PowerPoint Templates, Diagrams and Charts
DIRECT AC-DC
ELECTRONIC
CONVERTER
TOPOLOGY.
Presented by:
Bilal Ahmad.
Areez Irfan.
Hamza Ahmad.

3. CONTENTS.
 Introduction.
 Converter Topologies.
 Implementation Design.
 Simulation Results.

4.  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.

5.  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.

6. 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 energy Electrical energyElectromagnetic damping

7. `
 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.

8. 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.

9.  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.

10. DUAL POLARITY BOOST CONVERTER
FOR
DIRECT AC-DC CONVERSION.

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

12. 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.

13.  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.

14.  Feedback control circuit.
 Gate driver circuit.
 Startup circuit.

15. IMPLEMENTATION.

16. SIMULATION RESULT.

18. Any Questions