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Dipl.-Ing. Tobias Gemaßmer

Dr.-Ing. Tobias Gemaßmer

Former Research Assistant
Tobias GemassmerBhz9∂gkndriveline com


Forschungsprojekte
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Veröffentlichungen
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KIT Scientific Publishing

PCIM Europe 2015, International Conference and Exhibition for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management

Inverter nonlinearities and machine spatial harmonics yield unwanted machine current harmonics, causing control loop instabilities, additional losses and torque ripples. In this paper a method is presented that allows online identification and compensation of both effects for anisotropic permanent magnet synchronous machines with nonlinear magnetics. The method requires no additional sensors and only fundamental component machine model parameters. It can be implemented easily in existing inverter systems by software updates. Test bench measurements show significant improvements in the whole operational area. Measurements at nominal operation result in a motor current total harmonic distortion of 0.28 % which is less than a seventh of the uncompensated value. The functional principle is transferable to other machine types or grid applications enabling the mitigation of current harmonics in a wide field of applications.

IEEE International Conference on Industrial Technology (ICIT), 2015

High performance interior permanent magnet syn-chronous machines show nonlinear magnetics due to saturation and cross-coupling. Nonlinear differential equations describe these phenomena and make feedback control challenging. This paper presents a predictive control method to precisely control the dynamics of these machines. Four real-time capable strategies to online identify transient trajectories are proposed: Two straight line trajectories, a strategy that yields a fast torque response and a strategy that reaches the reference values in a short amount of time. A predictive control method to force the machine to precisely follow the selected trajectory is developed and analyzed using simulations and test bench measurements. Thus, advantages and disadvantages of specific trajectories are identified. This allows the selection of a proper strategy depending on the drive requirements.

International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), 2014

2014 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Ischia, Italy,

Highly utilized permanent magnet synchronous machines show magnetic saturation and cross-coupling effects. These phenomena are described by nonlinear differential equations and make feedback current control of the machine challenging. State of the art current control methods usually ignore these effects and hence do not produce optimal results in transient operation or in operation at the inverter voltage limit. Therefore, this paper presents a method to design a current controller taking into account saturation and dynamic cross-coupling. Feed forward calculation of transient quantities in realtime enables complete decoupling and dead-beat behavior which is experimentally validated by test bench measurements. With this approach, strongly nonlinear, highly utilized synchronous machines can be successfully controlled achieving best control quality in all operational conditions.

International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), 2014

This paper describes and investigates different dynamic overmodulation strategies applied to highly dynamic current control of interior permanent magnet synchronous machines. Although the machine is highly utilized, which indicates significant saturation characteristics, a linearized PI-Controller with excellent dynamic performance is used. The impact of voltage limitation with use of overmodulation on the current control quality is investigated and described.

PCIM Europe 2014, Nuremberg, Germany

EPE'13 ECCE Europe, Lille, France

This paper presents the analysis of current harmonics in an inverter-driven interior permanent magnet machine for different modulation methods. In contrast to other approaches, the influence of the saliency (Ld <> Lq) on the harmonics is being considered. By use of the rms-value of the currents, analytically closed equations can be deduced and tedious Fourier analyses of single harmonics can be avoided. The derivation of the analytic equations is described and the results are verified by numerical simulation as well as by experimental results.

PCIM Europe 2013, Nuremberg, Germany

In automotive applications, efficiency of the drive train is very important due to the limited energy in the battery. Improvement can be achieved by increasing the inverter output voltage through overmodulation. This can be used for either increasing output power or reducing power losses.
This paper presents a new strategy of voltage limitation for the current control of three-phase electric drives. The proposed limitation scheme allows the use of dynamic rotor-oriented current control with no modifications for operation in overmodulation range. The novel limitation structure is described and verified through simulations and experimental results.



abgeschlossene studentische Arbeiten
Titel Typ Bearbeiter
Bachelorarbeit

Marina Botros

Bachelorarbeit
Diplomarbeit

Andreas Greulich

Diplomarbeit

Jules Valere Taptso Fotso

Masterarbeit

Mathias Schnarrenberger

Diplomarbeit

Hassan Ennadifi

Bachelorarbeit

Simon Decker

Bachelorarbeit

Marcel Nophut

Bachelorarbeit
Studien-/Bachelor- oder Diplom-/Masterarbeit
Diplomarbeit

Jochen Braun

Studienarbeit

Jürgen Thoma

Studienarbeit

Kai Märzhäuser

Studienarbeit

Philipp Hofmeier

Diplomarbeit

Michael Eberlin

Diplomarbeit (extern)

Patrick Winzer

Diplomarbeit

Mohamed Said Zamit

Diplomarbeit
Diplomarbeit (extern)

Johannes Dréwniok

Studienarbeit

Mohamed Said Zamit

Studienarbeit
Studienarbeit (extern)
Studienarbeit