STATIC POWER CONVERSION I
EEE-463 Lecture Notes
A. Prof. Dr. Canras Batunlu
METU Northern Cyprus Campus
L1
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Power Electronics
I. What is power electronics?
II. The history
III. Applications
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1) Definition
• Power Electronics:
is the electronics applied to conversion and control of
electric power.
Range of power scale :
milliwatts(mW) megawatts(MW) gigawatts(GW)
• A more exact explanation:
The primary task of power electronics is to process and
control the flow of electric energy by supplying voltages
and currents in a form that is optimally suited for user
loads.
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Conversion of electric power
Electric Other names for electric
Power Power Power power converter:
input output
Converter -Power converter
-Converter
-Switching converter
Control
input -Power electronic circuit
-Power electronic converter
Changeable properties in
Two types of electric power
conversion
DC(Direct Current) Magnitude
Frequency, magnitude,
AC (Alternating Current)
number of phases
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Power Electronics
Power Electronics : What is?
Power electronics are the application of solid-state electronics to the control
and conversion of electric power.
Use of semi conductor devices for optimal conversion and control of
electrical energy.
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Power Electronics Integration
Switching on and off gives pulsed energy flow – that is why we need energy
storage elements as well to give “smooth” control of power flow.
Energy storage elements for smooth power flow:
Inductors smooth current – they oppose change in their current.
Capacitors smooth voltage - they oppose change in their voltage.
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Classification of power converters
Power
output
Power DC AC
input
AC to AC converter
AC AC to DC converter ( Fixed frequency : AC controller
(Rectifier) Variable frequency: Cycloconverter
or frequency converter)
DC DC to DC converter DC to AC converter
(Chopper) (Inverter)
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2) History
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3) The interdisciplinary nature
William E. Newell’s description
Electronics Power
Power
Electronics
Continuous,
discrete
Control
Power electronics is the interface between electronics and power.
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Interdisciplinary Nature of Power Electronics
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Scope and Applications
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Industrial applications
• Motor drives
• Electrolysis
• Electroplating
• Induction heating
• Welding
• Arc furnaces and ovens
• Lighting
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Transportation applications
• Trains & locomotives
• Subways
• Trolley buses
• Magnetic levitation
• Electric vehicles
• Automotive electronics
• Ship power systems
• Aircraft power systems
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Utility systems applications
• High-voltage dc transmission(HVDC)
• Flexible ac transmission(FACTS)
• Static var compensation & harmonics
suppression: TCR, TSC, SVG, APF
• Custom power & power quality control
• Supplemental energy sources :
wind, photovoltaic, fuel cells
• Energy storage systems
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Power supplies for electronic equipment
• Telecommunications
• Computers
computer
• Office equipment server
• Electronic instruments
• Portable or mobile
electronics
Telecommunication
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Residential and home appliances
• Lighting
• Heating
• Air conditioning
• Refrigeration & freezers
• Cooking
• Cleaning
• Entertaining
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Applications in space technology
• Spaceship power systems
• Satellite power systems
• Space vehicle power
systems
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Other applications
• Nuclear reactor control
• Power systems for
particle accelerators
• Environmental
engineering
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Power Electronics Integration
1.Semi conductor switches
2.Devices Drivers
3.Passive Components – capacitors & inductors
4.Busbars and connectors
5.Cooling systems
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Research
Thermal Characterisation and Reliability Analysis of Power Electronic
Devices in Wind and Solar Energy Systems
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Power Processor as a Combination of
Converters
• Most practical topologies require an energy
storage element, which also decouples the input
and the output side converters
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Power Electronic Conveters
AC to DC Converter (Rectifier): Converts AC voltage into a fixed DC voltage.
The input voltage to rectifier could be either single phase or three phase.
DC to AC Converter (Inverter): Coverts DC input voltage into AC.
AC to AC Converter (Voltage regulator): Convert a fixed AC input voltage into
variable AC output voltage.
DC to DC Converter (DC Chopper): Converts a fixed DC input voltage into
variable DC voltage or vice versa. The DC output voltage is controlled by
varying of duty cycle.
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Applications Power Electronics Boost Converter
Solar Systems
MPP tracker
k
Iph
Load
= IO
VPV VO VL
PV =
DC-DC
converter
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Applications Power Electronics Boost Converter
Battery
= DC-DC converter
=
DC-DC converter DC-AC inverter Grid
= ~
PV = =
Filter ~
DC-Link
Load
MPP tracker Data Acquisition
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Applications Power Electronics Boost Converter
Wind Energy Systems
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Applications Power Electronics Boost Converter
Speed Control of Elctrical Drives
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Applications Power Electronics Boost Converter
Electric Cars
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Basic Principle of Switch-Mode Synthesis
• Constant switching frequency
pulse width controls the average
L-C filters the ripple
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Power Flow through Converters
• Converter is a general term
• An ac/dc converter is shown here
• Rectifier Mode of operation when power from ac to dc
• Inverter Mode of operation when power from dc to ac
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AC Motor Drive
• Converter 1 rectifies line-frequency ac into dc
• Capacitor acts as a filter; stores energy; decouples
• Converter 2 synthesizes low-frequency ac to motor
• Polarity of dc-bus voltage remains unchanged
– ideally suited for transistors of converter 2
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Matrix Converter
• Very general structure
• Would benefit from bi-directional and bi-polarity switches
• Being considered for use in specific applications
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DC/DC Power Electronic Boost Converter
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DC/DC Boost Converter
The output voltage can be maintained at desired level by controlling the
switching time sequence which can be calculated as:
TON TOFF TP 1 f (1)
where f is the switching frequency.
TON DT P TOFF (1 D )TP (2,3)
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DC/DC Boost Converter
Switching-on state
Considering ideal components, when switch is turned on, voltage applied on
inductor is;
diin i
L VI L in (4).
dt DTP
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DC/DC Boost Converter
Switching-off state
Where L is the inductance; when switch is off:
diin iin
L VI VO L (5)
dt (1 D)TP
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DC/DC Boost Converter
By equating eqns. 4 and 5;
DTPVI (1 D)TP
(VI VO ) (6)
L L
VI (1 D)VO
(7)
∴ for a lossless system input power (Pi) is equal to the output power(Po)
Pin = Pout = Iin VI = IoVo (8)
I o (1 D) I I (9)
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DC/DC Boost Converter
VI
Toff Ton
TP t
II
ID t
Is t
t
Current Signal Characteristics of boost converter
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Power Electronic Conveters
Voltage source DC-AC inverter linked with a DC-DC boost converter
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Thyristors – The heart of HVDC - ABB
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End of Second Section
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