1. Seminar on
Solid State Transformer(SST)
and its implementations
BY
MUDA BALA NAIK
M200207EE
2. Contents
Introduction
About solid state transformer,
Disadvantages of classical transformer,
Classification of SST topology,
Applications
Advantages of SST
Conclusion
Reference
3. Introduction
About Solid State Transformer (SST)?
Disadvantages of Conventional Transformer.
Advantages of SST over Conventional Transformer.
Topologies of SST.
Applications of SST
4. About Solid State Transformer?
Solid state transformer (SST) is an element/component
consisted of multi stage power electronics converters
isolated with high frequency transformer
A solid state transformer can actively regulate voltage
and current.
5. Disadvantages of classical Distribution
Transformer
Bulky size and heavy weight.
Transformer oil can be harmful when exposed to the
environment.
Core saturation produces harmonics, which results in large
inrush currents.
Many more….
6. Classification of SST topology
There are many topologies which can be categorized as below
7. Single stage
Its simplest SST topology.
It has only a direct power conversion with transformer
isolation to step down the HC to LV.
It operates in direct DC-DC or AC-AC power conversion
stages offer better efficiency and higher reliability.
It uses phase shift angle between the secondary and the
primary bridges to control the direction and magnitude of
power transfer.
8. Advantages
It can be used in bidirectional power flow with four-
quadrant switches which help to improve control strategy
and regulate harmonic content.
It can control power transferred to the load between
bridges.
9. Single phase dual active bridge converter
The single phase Dual Active Bridge (DAB) converter
consists of a full bridge circuit on the primary and the
secondary side of the high frequency transformer.
The DAB utilizes the leakage inductance of the
transformer to provide energy storage and to modify the
shape of the current waveform.
15. Two stage
It has additional design of DC-link either on the HV side
or the LV side.
The power flow is bidirectional though it can be used
into unidirectional by deploying an uncontrolled
rectifier at the LV side of the AC-DC converter.
It has capability to reduce the harmonic distortion in
both input and output current under unbalanced load
conditions.
16. Three stage
It can optimize the performance of distribution and
transmission grids apart from lower volume and weight in
this SST
The three stage SST topologies are designed with two DC
links that are able to address power quality issues and also
supply and utilize any devices.
It can be differentiated on basis of voltage and frequency
MEDIUM VOLTAGE STAGE(AC-DC)
LOW VOLTAGE STAGE (DC-AC)
MEDIUM FREQUENCY CONVERTER
HIGH FREQUENCY TRANSFORMER
17. Trending applications of SST
SOLAR PHOTOVOLTAIC APPLICATION
WIND ENERGY CONVERSION SYSTEM
TRACTION APPLICATION
OTHER FUTURE APPLICATION
RENEWABLE ENERGY SOURCE
MICROGRID APPLICATION
18. Renewable Energy Source
As renewable energy sources are gaining interest in order to conserve
energy for future generation.
As some of the RESs are generated as DC power and require the power
conversion i.e. inverter which would decrease the power efficiency.
In addition, a bulky converter is also required in order to be connected
to the conventional power grid. In this context the replacement of a
conventional power transformer by SST is the solution to many these
issues.
More importantly as most of the RESs systems disconnect during
overvoltage conditions.
The SST provides a solution by controlling the power output and the
power could still be generated.
19. Solar Photovoltaic Application
As PV generates a low voltage, there is a effective options
to connect solar PV to load or network. Thus a low
frequency transformer is utilised or large PV arrays are
used. These have some disadvantages.
Hence SST is alternative
A dual active bridge inverter topology based on SST
applied in PV module arrays is proposed where high
frequency transformers are utilized instead of bulky
medium voltage line frequency ones.
20. Wind Energy Conversion System
Main reason behind SST in wind energy conversion system
are reduction in weight and volume.
SST could offer reduction in fluctuation of voltage.
And many more future applications
22. Advantages of SST
Small in weight and volume.
Power factor correction and reactive power compensation
Harmonic isolation
Fault isolation
Environmental benefit
Instantaneous voltage regulation
23. Conclusion
Solid state transformer (SST) is emerging technology integrating
with a transformer, power electronics converters and control
circuits that could help in developments in many areas such as
smart grids, traction systems and with renewable energy sources
(RESs).Here Dual active bridge converter is implemented for solid
state transformer. A high frequency transformer is used to minimize
the bulk of passive components. Four quadrant switch cells and
phase shift modulation to ensure that energy can flow in both
directions.
24. Reference
M. A. Hannan “State of the Art of SSTs: Advanced Topologies,
Implementation Issues, Recent Progress and Improvements” Year: 2020
| Volume: 8 | Journal Article | Publisher: IEEE
Hengsi Qin, Jonathan W. Kimball “Ac-ac dual active bridge converter
for solid state transformer” Energy Conversion Congress and
Exposition Year: 2009 | Conference Paper | Publisher: IEEE
Xu She;Alex Huang “Solid state transformer in the future smart
electrical system” Power & Energy Society General Meeting Year: 2013
| Conference Paper | Publisher: IEEE
