POWER ELECTRONICS
FOR RENEWABLE ENERGY
SYSTEMS
UNIT I INTRODUCTION
Environmental aspects of electric energy conversion: impacts of renewable
energy generation on environment (cost-GHG Emission) - Qualitative study
of different renewable energy resources: Solar, wind, ocean, Biomass, Fuel
cell, Hydrogen energy systems and hybrid renewable energy systems.
UNIT II ELECTRICAL MACHINES FOR RENEWABLE ENERGY
CONVERSION
Reference theory fundamentals-principle of operation
and analysis: IG, PMSG, SCIG and DFIG.
UNIT III POWER CONVERTERS
Solar: Block diagram of solar photo voltaic system -Principle of operation:
line commutated converters (inversion-mode) - Boost and buck-boost
converters- selection of inverter, battery sizing, array sizing Wind: Three
phase AC voltage controllers- AC-DC-AC converters: uncontrolled
rectifiers, PWM Inverters, Grid Interactive Inverters-matrix converters.
UNIT IV ANALYSIS OF WIND AND PV SYSTEMS
Stand alone operation of fixed and variable speed wind energy
conversion systems and solar system Grid connection Issues -Grid
integrated PMSG, SCIG Based WECS, grid Integrated solar system
UNIT V HYBRID RENEWABLE ENERGY SYSTEMS
Need for Hybrid Systems- Range and type of Hybrid systems- Case
studies of Wind-PV Maximum Power Point Tracking (MPPT)
UNIT II
ELECTRICAL MACHINES FOR RENEWABLE
ENERGY CONVERSION
Reference theory fundamentals-principle of operation
and analysis: IG, PMSG, SCIG and DFIG.
GENERATORS USED FOR WIND
ENERGY CONVERSION SYSTEM
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IG –power factor poor
SEIG- power factor improved
SCIG –constant speed WECS
DFIG(WRIG)- variable speed generator
PMSG –Permanent Magnet Synchronous Generator
Wind Turbine Generator
Output Curve
Induction Generators
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●
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Same basic construction as squirrel-cage induction motors
Drive at a speed greater than the synchronous speed
Not started as a motor
Operated by wind turbines, steam turbines, etc.
ECE 441
9
Self Excited Induction Generator
Speed –Torque curve
Double Fed Induction Generator
PMSG
Advantages over the DFIG
● The PMSG does not require DC excitation as the
magnetic field is produced by the permanent magnets
rather than by the coil.
● Hence, the PMSG does not require slip rings and brushes,
which reduces the weight, cost, losses, and maintenance
● PMSG, connected to the power electronic converter, can
operate at low speeds; hence, a gearbox is not required
Classification of PMSG
Based on the direction of the flux lines:
● Radial flux PMSGs
● Axial flux PMSGs and
● Transverse flux PMSGs
Based on the location of the permanent magnets on the
rotor:
● Surface inset PMSGs
● Surface mounted PMSGs and
● Interior PMSGs
Equivalent circuit of PMSG
Clarke’s Transformation
● It transforms abc quantity into stationary
●
coincides with phase a-axis and
by
● The equation
with
The inverse
and
leads the
Park’s Transformation
● It was proposed by Robert H. Park from MIT
● There are wide ranges of application from machine
simulation, control, drives, etc.
● This transform is one of the most important application for
power engineers.
Park’s Transformation (2)
Park’s Transformation (3)
● A vector
in space can be seen from several coordinate
● We can change from one coordinate to another coordinate
Park’s Transformation (4)
Park’s Transformation (5)
The abc to dqo transformation
The abc to dqo transformation (2)
The abc to dqo transformation (3)
The abc to dqo transformation (3)
Commonly Used Reference Frame
Transformation Between Reference Frame
Application to Voltage Equation
Application to Voltage Equation(2)