Summary: | This work demonstrates the capability of a power electronic based power hardware-inthe-
loop (PHIL) platform to emulate electric machines for the purpose of a motor drive
testbench with a particular focus on induction machine emulation. PHIL presents advantages
over full-hardware testing of motor drives as the PHIL platform can save space and
cost that comes from the physical construction of multiple electric machine test configurations.
This thesis presents real-time models that were developed for the purpose of PHIL
emulation. Additionally, real-time modeling considerations are presented as well as the modeling
considerations that stem from implementing the model in a PHIL testbench. Next, the
design and implementation of the PHIL testbench is detailed. This thesis describes the
design of the interface inductor between the motor drive and the emulation platform. Additionally,
practical implementation challenges such as common mode and ground loop noise
are discussed and solutions are presented. Finally, experimental validation of the modeling
and emulation of the induction machine is presented and the performance of the machine
emulation testbench is discussed. === Master of Science === According to the International Energy Agency (IEA), electric power usage is increasing
across all sectors, and particularly in the transportation sector [1]. This increase is apparent
in one's daily life through the increase of electric vehicles on the road. Power electronics
convert electricity in one form to electricity in another form. This conversion of power is
playing an increasingly important role in society because examples of this conversion include
converting the dc voltage of a battery to ac voltage in an electric car or the conversion of
the ac power grid to dc to power a laptop. Additionally, even within an electric car, power
converters transform the battery's electric power from a higher dc voltage into lower voltage
dc power to supply the entertainment system and into ac power to drive the car's motor.
The electrification of the transportation sector is leading to an increase in the amount
of electric energy that is being consumed and processed through power electronics. As was
illustrated in the previous examples of electric cars, the application of power electronics
is very wide and thus requires different testbenches for the many different applications.
While some industries are used to power electronics and testing converters, transportation
electrification is increasing the number of companies and industries that are using power
electronics and electric machines.
As industry is shifting towards these new technologies, it is a prime opportunity to change
the way that high power testing is done for electric machines and power converters. Traditional
testing methods are potentially dangerous and lack the flexibility that is required
to test a wide variety of machines and drives. Power hardware-in-the-loop (PHIL) testing
presents a safe and adaptable solution to high power testing of electric machines. Traditionally,
electric machines were primarily used in heavy industry such as milling, processing, and
pumping applications. These applications, and other applications such as an electric motor
in a car or plane are called motor drive systems. Regardless of the particular application
of the motor drive system, there are generally three parts: a dc source, an inverter, and
the electric machine. In most applications, other than cars which have a dc battery, the
dc source is a power electronic converter called a rectifier which converts ac electricity from
the grid to dc for the motor drive. Next, the motor drive converts the dc electricity from
the first stage to a controlled ac output to drive the electric machine. Finally, the electric
machine itself is the final piece of the electrical system and converts the electrical energy to
mechanical energy which can drive a fan, belt, or axle. The fact that this motor drive system
can be generalized and applied to a wide range of applications makes its study particularly
interesting.
PHIL simplifies testing of these motor drive systems by allowing the inverter to connect
directly to a machine emulator which is able to replicate a variety of loads. Furthermore,
this work demonstrates the capability of PHIL to emulate both the induction machine load
as well as the dc source by considering several rectifier topologies without any significant
adjustments from the machine emulation platform.
This thesis demonstrates the capabilities of the EGSTON Power Electronics GmbH COMPISO
System Unit to emulate motor drive systems to allow for safer, more flexible motor drive system testing. The main goal of this thesis is to demonstrate an accurate PHIL emulation
of a induction machine and to provide validation of the emulation results through
comparison with an induction machine.
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