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Matrix Converter
Technology Development
Matrix converter is an "all silicon" solution for AC-AC conversion, removing the
need for reactive energy storage components used in conventional rectifierinverter based systems. Converter topology and control technique of a Matrix
Converter is established through this development project. This is a joint
activity by CDAC, Thiruvananthapuram and IISc Bangalore.
A direct 3 Phase to 3 Phase Matrix Converter consists of nine bi-directional
switches that are used to connect the input phases directly to the output
phases of the converter. The switching of these bi-directional switches is then
modulated to produce the desired output voltage and frequency. Matrix
converters offer many advantages over traditional topologies such as the ability
to regenerate energy back to the utility, sinusoidal input and output currents
and controllable input current displacement factor. The size of the converter
can also be reduced since there are no large reactive components for energy
storage. Major applications are listed below.
• m phase to n phase conversion
• All silicon motor drives with capability of regeneration
• Grid interface for non conventional energy sources
• Variable voltage, variable frequency power supplies
The development of the above technology involved the development of various
critical sub systems and algorithm for switching modulation. The control of
Matrix Converter is achieved with a Micro controller-FPGA based digital
hardware with suitable intelligence to execute the controlled commutation of
the bi directional switches. A circuit for sensing of current direction was
integrated in the gate drive circuit. ‘Venturini modulation’ strategy was
implemented and used for direct matrix converter.
Outcome
One proto unit with a rating of 50kVA is developed and demonstrated as a part
of this project. A 5kVA proto unit is also developed and demonstrated in various
exhibitions.
Proto developed at CDAC
Proto developed at IISc
At rated load the input PF is unity and the THD of input current is 2.5%. As a
part of this project a 5kVA proto unit of Direct Matrix Converter is developed
and tested by IISc Bangalore
Technology Development
Future scope
The converter topology, control circuits and the algorithm for control of the
converter etc. has been developed and thoroughly tested in this project.
The technology shall be extended for suitable applications. To start with, the
system has been tested as a static frequency converter and as an induction
motor drive. More developments shall be undertaken in the following
applications.
•
Frequency changing static power supply application like aircraft ground
power supply
•
Development of Matrix Converter as an AC drive considering industrial
requirements
•
Using Matrix Converter as grid interface for non-conventional AC
sources.
•
Application of Matrix converters in EVs and hybrid EVs.
•
Matrix converter for applications like Loop Power Flow Controller in
power systems. Loop power flow controllers are relevant to power system
with large scale distributed generation.