@article{Werner2020, author = {Werner, Ulrich}, title = {3D-model for active vibration control of rotating machines mounted on active machine foot mounts using vibration mode coupling by asymmetry}, series = {Journal of Vibration Engineering \& Technologies}, volume = {9}, journal = {Journal of Vibration Engineering \& Technologies}, editor = {werner, ulrich}, publisher = {Springer}, doi = {10.1007/s42417-020-00252-z}, pages = {613-641}, year = {2020}, abstract = {Purpose: In this work, active vibration control of rotating machines mounted on active machine foot mounts is investigated. Methods: Therefore, a simplified 3D model is derived and the mathematical coherences are described. Different mathematical solutions are presented for special boundary conditions and a method called "vibration mode coupling by asymmetry" is derived. Results: It could be shown that a symmetrical system with a machine design, where the center of gravity lies symmetrically between the machine feet with a vertical distance, and where all actuators are identical, represents a system, where all vibration shapes but one can be influenced by the controllers, when the gyroscopic effect can be neglected. In this case, a special vibration shape occurs—where the machine is only rotating at its vertical axis—which cannot be influenced by the controllers. When the stiffness and/or damping in axial and/or horizontal direction of only one actuator will be changed—which will lead to an asymmetrical system—the vibration shape with pure rotation at the vertical axis will not exist anymore. Now, the vibration shapes will become more coupled and they all can be influenced by the controllers, which is here called "vibration mode coupling by asymmetry". Conclusions: With the here presented method of "vibration mode coupling by asymmetry", all vibrations mode shapes can now be active controlled.}, language = {en} } @article{Werner2018, author = {Werner, Ulrich}, title = {Vibration control of large induction motors using actuators between motor feet and steel frame foundation}, series = {Mechanical Systems and Signal Processing}, volume = {112}, journal = {Mechanical Systems and Signal Processing}, editor = {werner, ulrich}, publisher = {Elsevier}, doi = {10.1016/j.ymssp.2018.04.033}, pages = {319-342}, year = {2018}, abstract = {In the paper a theoretical analysis is deduced regarding vibration control of large induction motors - power rating >=1 MW - with roller bearings, using actuators between motor feet and a soft steel frame foundation. Based on a multibody model, the mathematical coherences are shown, including the feedback control system. Afterwards a numerical example of a soft mounted, converter driven, 2-pole induction motor (1.6 MW) with ball bearings is presented, where the bearing housing vibrations and the foundation vibrations are analyzed with and without control system. It could be shown, that without vibration control system the operating speed range cannot be used completely because of resonances, caused by the soft foundation. Therefore, critical speed areas occur, where steady state operation is not possible. However, with the vibration control system, the whole operating speed range can be used. The aim of the paper is to show the capability of using a vibration control system with actuators between motor feet and a soft foundation, for avoiding off-limits areas for the operation speed of large induction motors.}, language = {en} } @inproceedings{Werner2018, author = {Werner, Ulrich}, title = {Increasing the threshold of vibration stability of soft mounted induction motors with elastic rotors and sleeve bearings using active motor foot mounts}, series = {Proceedings of ISMA2018 including USD2018}, booktitle = {Proceedings of ISMA2018 including USD2018}, editor = {Werner, Ulrich}, pages = {2509-2523}, year = {2018}, abstract = {In the paper, the threshold of vibration stability of induction motors with flexible shafts and sleeve bearings, mounted on soft steel frame foundations with active motor foot mounts, is analyzed. The developed model is based on a multibody model, considering electromagnetic influence, stiffness and internal damping of the rotor, stiffness and damping of the bearing housings and end shields, stiffness and damping of the foundation and stiffness and damping of the oil film of the sleeve bearings. Additionally the stiffness and damping of the motor foot mounts - which are positioned between the motor feet the soft steel frame foundation - are considered, as well as the controlled forces which are applied in the vibration system by the motor foot mounts, using PD-controllers. The aim of the paper is to unite all these influences in a mathematical model and to derive a procedure for calculating the threshold of vibration stability. Based on a numerical example it can be shown, that the threshold of stability can be pushed to very high rotor speeds, using active motor foot mounts.}, language = {en} } @inproceedings{Werner2025, author = {Werner, Ulrich}, title = {Active vibration control of rotating machines with current-controlled electrodynamic actuators between machine feet and steel frame foundation using vibration mode coupling by asymmetry - a theoretical analysis}, editor = {werner, ulrich}, pages = {10}, year = {2025}, abstract = {In the paper a simplified 3D-model of a rotating machine is presented where current-controlled electrodynamic actuators are mounted between machine feet and an elastic steel frame foundation and where the vertical machine feet vibrations are fed back to separate controllers for active vibration control. It could be shown, that if an asymmetrical system is chosen - where one actuator has a different stiffness in the horizontal plane - all rigid body modes are more coupled and can now be influenced by the control system. With this concept critical speeds can be avoided in the operation speed range, independent of the foundation properties.}, language = {en} } @incollection{Werner2020, author = {Werner, Ulrich}, title = {Calculation procedure to derive the threshold of vibration stability of soft mounted induction motors with elastic rotors and sleeve bearings fixed on active motor foot mounts for arbitrary controller structures}, series = {12th International Conference on Vibrations in Rotating Machinery}, booktitle = {12th International Conference on Vibrations in Rotating Machinery}, editor = {werner, ulrich}, address = {CRC Press}, isbn = {9781003132639}, pages = {12}, year = {2020}, abstract = {In the paper an iterative calculation procedure is presented for deriving the threshold of vibration stability of induction motors with flexible shafts and sleeve bearings, mounted on soft steel frame foundations with active motor foot mounts and arbitrary controller structures. The mathematical model considers the electromagnetic influence, stiffness and internal damping of the rotor, stiffness and damping of the bearing housings with end shields, of the foundation and of the oil film of the sleeve bearings, as well as the stiffness and damping of the motor foot mounts and the controlled forces, which are applied by the motor foot mounts.}, language = {en} } @inproceedings{Werner2024, author = {Werner, Ulrich}, title = {Active vibration control of an induction motor with sleeve bearings and electrodynamic actuators between motor feet and steel frame foundation regarding electromagnetic excitation}, series = {Journal of Physics: Conference Series}, booktitle = {Journal of Physics: Conference Series}, number = {2909}, editor = {werner, ulrich}, publisher = {IOP Publ.}, doi = {10.1088/1742-6596/2909/1/012001}, pages = {13}, year = {2024}, abstract = {The paper presents a theoretical analysis of active vibration control of an induction motor with sleeve bearings and electrodynamic actuators between motor feet and steel frame foundation, where the vertical vibration velocities of the motor feet are lead back to separate controllers. Based on a 2D model, the mathematical coherences of the controlled vibration system are presented, as well as a numerical example of a 2-pole induction motor. The threshold of vibration stability is calculated as well as frequency responses regarding bearing housing vibrations caused by electromagnetic forces in the air gap of the induction motor, due to a static magnetic eccentricity between rotor and stator. Also the actuator forces are analyzed. With this analysis, the effectiveness of the developed active vibration control system can be demonstrated.}, language = {en} } @inproceedings{WachterWernerHerzogetal.2022, author = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg and Bauer, Christian}, title = {1D-Simulation and experimental validation of active vibration damping of an induction motor mounted on an elastic steel frame foundation using modified integral controllers}, editor = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg and Bauer, Christian}, pages = {3605 -- 3619}, year = {2022}, abstract = {Preventing vibrations in electrical motors that are mounted on elastic foundations could help to open up operating speed ranges in which it was previously not allowed to operate as a permanent operating point. In the present paper, theoretical and practical aspects of an active vibration control of a two-pole induction motor (11 kW) mounted on a drive system and an elastic steel frame foundation are investigated. In preparation for simulating state space models with more degrees of freedom, a theoretical analysis derived from the existing test bench reduced to a two-mass-oscillator - motor, actuator and foundation - is done, to show which components are essential. Based on this analysis, simulations with a state space model and modified integral control algorithms will be discussed - in open and closed loop. Results of simulations of vibration reduction due to the control algorithm and disturbance response will be compared to experimental results from the test bench. Additionally, the power consumption of an actuator is analysed.}, language = {en} } @inproceedings{WachterWernerHerzog2025, author = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg}, title = {Vibration analysis including active vibration control of a 11 kW two-pole induction motor with elastic steel frame foundation based on detailed 3D FE-models and experimental modal analyses}, editor = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg}, pages = {10}, year = {2025}, abstract = {This paper describes the vibration behaviour of a small 11 kW two pole induction motor, which is mounted on an elastic steel frame foundation with an active vibration control system (AVCS). On the one hand the paper presents detailed 3D finite element models for vibration analysis and compares the vibration simulation results to vibration measurement results and on the other hand, the paper presents a comparison of different settings of the test bench-motor mounted directly on the steel frame foundation and motor mounted on the developed AVCS. Further, the comparison of experimental modal analyses with open and close control loop operation are shown to demonstrate the efficiency of the AVCS. Finally, the paper gives an outlook about the scaling of the AVCS for motors in the megawatt range.}, language = {en} } @article{Werner2023, author = {Werner, Ulrich}, title = {Generalized mathematical formulation for active vibration control of rotating machines with voltage-driven electrodynamic actuators between machine feet and steel frame foundation}, series = {ZAMM- Journal of Applied Mathematics and Mechanics}, volume = {103}, journal = {ZAMM- Journal of Applied Mathematics and Mechanics}, number = {8}, editor = {Werner, Ulrich}, publisher = {Wiley}, issn = {1521-4001}, doi = {10.1002/zamm.202200394}, pages = {19}, year = {2023}, abstract = {In the paper, a generalized mathematical formulation for active vibration control of rotating machines with voltage-driven electrodynamic actuators between machine feet and steel frame foundation is derived. This generalized mathematical formulation is based on a state space description in the Laplace domain, where the state space vector is lead back, for considering the actuator forces. The aim of the paper is that this generalized mathematical formulation can be used now for arbitrarily models of rotating machines—1D-, 2D-, and 3D-models— with voltage-driven electrodynamic actuators between machine feet and steel frame foundation, and where the vertical vibration acceleration at each machine foot is lead back to a separate controller. Of course, this mathematical formulation can also be adopt easily to other boundary conditions. As an example, the generalized mathematical formulation is used here for a 1D-model of a rotating machine, to calculate the poles and the frequency response functions.}, subject = {Rotating machines}, language = {en} } @inproceedings{WachterWernerHerzogetal.2024, author = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg and Bauer, Christian}, title = {Analysis of the controller and damping behavior of an electrodynamic actuator system for an 11 kW two-pole induction motor on an elastic steel frame foundation}, editor = {Wachter, Raimund and Werner, Ulrich and Herzog, Hans-Georg and Bauer, Christian}, publisher = {Berlin}, address = {VDE}, isbn = {978-3-8007-6391-7}, pages = {4}, year = {2024}, abstract = {This paper describes the open loop configuration of the simulation and measurement of a controller hardware and a voice coil actuator for vibration control of a 11 kW motor on steel frame foundation. The paper discusses the phase response regarding damping behavior of the actuator force and identifies approaches for improvements. Further, the paper offers a comparison of measurements as a result of the run up of the motor in open loop and closed loop operation with rubber elements and with steel springs. It is shown that all vibration modes with vertical movement at the motor feet can be reduced. Finally, the paper discusses the change in the system's natural frequencies due to the replacement of the rubber elements by steel springs.}, subject = {Induction motors}, language = {en} } @article{Werner2023, author = {Werner, Ulrich}, title = {Active vibration control of a rotating machine with voltage-driven electrodynamic actuators between machine feet and steel frame foundation under multiple base excitations}, series = {Journal of Vibration Engineering \& Technologies}, volume = {12}, journal = {Journal of Vibration Engineering \& Technologies}, editor = {werner, ulrich}, publisher = {Springer}, doi = {10.1007/s42417-023-01100-6}, pages = {3977-4004}, year = {2023}, abstract = {Purpose: In the paper, a theoretical analysis—based on a 2D multibody model—is presented regarding active vibration control of a rotating machine with voltage-driven electrodynamic actuators between machine feet and steel frame foundation under multiple base excitations. Methods: Mathematical formulations are derived in the time domain and then transferred into the Laplace domain, where a state space formulation is used to describe the controlled vibration system. With this mathematical formulations, it is possible to analyze separately the two different kinds of actuator forces—the actuator forces, caused by the motion-induced voltage and the actuator forces caused by the control system—and their influence on the vibration behavior. Afterward, the mathematical formulations are transferred into the Fourier domain, for considering harmonic excitations of the base. Also a numerical example is presented, where different cases regarding machine mounting and operation conditions are investigated and compared to each other. Results: It could be clearly demonstrated that with the presented control system, most of the resonance peaks in the frequency responses could be strongly damped. Conclusions: With the presented mathematical formulations, the controlled vibration system can be well described, considering separately the two different kinds of electrodynamic actuator forces and their influence.}, subject = {Rotating machines}, language = {en} }