Current Harmonic Compensation in Dual Three-Phase Permanent Magnet Synchronous Machines
Karttunen, Jussi (2017-06-30)
Väitöskirja
Karttunen, Jussi
30.06.2017
Lappeenranta University of Technology
Acta Universitatis Lappeenrantaensis
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-335-098-4
https://urn.fi/URN:ISBN:978-952-335-098-4
Tiivistelmä
Dual three-phase electric machines can bring significant benefits over conventional threephase
machines in many applications. Although increasing the phase number of the
electric machine can deliver significant advantages, it also introduces problems with
stator current harmonics. In dual three-phase machines, even a small voltage excitation
of certain frequency components can produce significant corresponding stator current
harmonics. Current harmonics cause adverse effects such as additional losses, which
degrade the efficiency of the machine. Thus, the target is usually to eliminate the
harmonics.
The established solution to eliminate current harmonics is to use some current harmonic
compensation method. In the literature, a variety of methods have been suggested for the
purpose. The objective of this doctoral dissertation is to show that in addition to the
traditional methods, an inverse-based current harmonic controller can be effectively used
to eliminate stator current harmonics in dual three-phase machines. Further, it is
demonstrated that, compared with the traditional methods, the inverse-based structure of
the proposed controller is very advantageous in the theoretical analysis. Another novel
approach for harmonic compensation is obtained by recognizing that the current
harmonics can be modelled as caused by a lumped disturbance signal. Hence, it is possible
to use a disturbance-observer-based control to eliminate the current harmonics. The
results show that the disturbance observer provides a high-performance alternative to the
conventional harmonic compensation solutions.
The well-known current harmonic compensation methods reported in the literature and
the new approaches developed in this doctoral dissertation are extensively compared in
terms of stability and performance. A detailed theoretical analysis of the methods is given
by using a modern multi-input multi-output technique based on a structured singular value
analysis. In addition, the performance of the methods is studied with experimental results.
The main contribution of this dissertation is to establish the most favourable current
harmonic compensation method for dual three-phase permanent magnet synchronous
machines. All in all, the results show that the current harmonics can be eliminated
robustly and efficiently with the right type and parameters of the harmonic compensation.
machines in many applications. Although increasing the phase number of the
electric machine can deliver significant advantages, it also introduces problems with
stator current harmonics. In dual three-phase machines, even a small voltage excitation
of certain frequency components can produce significant corresponding stator current
harmonics. Current harmonics cause adverse effects such as additional losses, which
degrade the efficiency of the machine. Thus, the target is usually to eliminate the
harmonics.
The established solution to eliminate current harmonics is to use some current harmonic
compensation method. In the literature, a variety of methods have been suggested for the
purpose. The objective of this doctoral dissertation is to show that in addition to the
traditional methods, an inverse-based current harmonic controller can be effectively used
to eliminate stator current harmonics in dual three-phase machines. Further, it is
demonstrated that, compared with the traditional methods, the inverse-based structure of
the proposed controller is very advantageous in the theoretical analysis. Another novel
approach for harmonic compensation is obtained by recognizing that the current
harmonics can be modelled as caused by a lumped disturbance signal. Hence, it is possible
to use a disturbance-observer-based control to eliminate the current harmonics. The
results show that the disturbance observer provides a high-performance alternative to the
conventional harmonic compensation solutions.
The well-known current harmonic compensation methods reported in the literature and
the new approaches developed in this doctoral dissertation are extensively compared in
terms of stability and performance. A detailed theoretical analysis of the methods is given
by using a modern multi-input multi-output technique based on a structured singular value
analysis. In addition, the performance of the methods is studied with experimental results.
The main contribution of this dissertation is to establish the most favourable current
harmonic compensation method for dual three-phase permanent magnet synchronous
machines. All in all, the results show that the current harmonics can be eliminated
robustly and efficiently with the right type and parameters of the harmonic compensation.
Kokoelmat
- Väitöskirjat [1037]