192.

B. Krüger, S. Kratz, T. Theopold and S. Soter, "Wear Reduction Control Method in a Blade Pitch System of Wind Turbines" in 2019 IEEE 28th International Symposium on Industrial Electronics (ISIE), 2019, pp. 1107--1112.

Abstract:
Mechanical transformation of speed is needed in a lot of industrial applications but it is attended by backlash. Gear parts without closed linkage can accelerate and crash to another. So with the backlash comes the wear. There are many technical solutions and ideas to reduce the backlash by mechanical and electrical components and adaptions, but in most cases with the goal to increase the precision. In some applications, like the described pitch drive, the precision is not the problem and the increasing costs for backlash elimination are not to justified because the reduction of wear is more important. Further the extensive adaption has influence on functional safety and maintenance. This paper gives a short overview of mechanisms that reduce the wear in a given application without mechanical adaptions, only by adding a software module. In the first step backlash is detected and in dependence on its reason in a second step a reaction is induced by the drive to spare the mechanics.

191.

S. Kratz, B. Krüger, R. Wegener and S. Soter, "Integration of Photovoltaics into a Smart Trolley System Based on SiC-Technology" in 2018 IEEE 7th International Conference on Power and Energy (PECon), 2018, pp. 168--173.

Abstract:
This paper gives an insight to a research project with the aim of a fully electrified short-range public transportation in a German town called Solingen. It starts with an overview of the special characteristics of the existing fully isolated overhead contact system and then derives the projected system. A new silicone carbide power electronic and the necessary control algorithms for the direct integration of photovoltaic arrays are proposed and evaluated. The measurement of a first small volume 10kW prototype inverter shows that the integration can be done with high efficiency.

190.

A. Uphues, K. Nötzold, R. Wegener and S. Soter, "Crowbar-less ride through of asymmetrical gric faults with DFIG based WECS" in 2017 IEEE AFRICON, 2017, pp. 1026--1031.

Abstract:
Due to the increased renewable power penetration level renewable power plants have to provide low-voltage ride-through (LVRT) capability with simultaneous dynamic voltage support, to ensure the grid stability during grid faults. Concerning doubly fed induction generator (DFIG) based wind energy conversion systems (WECS) large electromotive forces and rotor currents, which may damage the rotor-side converter, or adversely affect the DFIG's controllability are induced into the rotor circuit in case of voltage dips. To handle and limit the rotor currents in case of asymmetrical voltage dips without crowbar triggering, a virtual resistance control approach based on the standard dq-control in the synchronous reference frame is discussed. The theoretical results are compared with those of more demanding virtual inductance control. The LVRT capability is verified with measurement results, recorded during a certification campaign at a 2.1 MW WECS concerning the Indian grid code.

189.

A. Uphues, K. Nötzold, R. Wegener and S. Soter, "DFIG's virtual resistance demagnetization for crowbar less LVRT" in 2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS), 2017, pp. 265--270.

Abstract:
Due to the increased renewable power penetration level renewable power plants have to provide low-voltage ride-through (LVRT) capability with simultaneous dynamic voltage support, to ensure the grid stability during grid faults. Concerning doubly fed induction generator (DFIG) based wind energy conversion systems (WECS) large transient electromotive forces (EMF) and rotor currents, which may damage the rotor-side converter (RSC), or adversely affect the controllability of the DFIG are induced into the rotor circuit in case of voltage dips. To limit the rotor currents and to accelerate the transient flux component's or transient electromotive force's damping respectively, a virtual resistance demagnetization approach based on the standard dq-control in the synchronous reference frame is discussed. The theoretical results are compared with those of more demanding virtual inductance and virtual impedance approaches. Additionally, to increase the IGBT's current conductivity, a reduction of switching losses due to a simple pulse pattern optimization is provided. The LVRT-capability is verified with measurement results, recorded during a certification campaign at a 2.1 MW WECS in India, concerning the Indian grid code.

188.

J. Holtz, "Advanced PWM and Predictive Control---An Overview", IEEE Transactions on Industrial Electronics, vol. 63, no. 6, pp. 3837--3844, 2016.

Abstract:
Synchronous optimal modulation and predictive current control and their preferred applications in drive control systems are described. Operation at low switching frequency is required to minimize harmonic distortion and switching losses, thus increasing the utilization of medium-voltage inverters and drive motors. Maximum fundamental output voltage is achieved by predictive overmodulation. Predictive torque control offers less attractions.

187.

A. Uphues, K. Nötzold, R. Wegener and S. Soter, "Comparison of parameter identification approaches with linearised process models based on RLS for induction machines with P {\textgreater} 100 kW" in 2016 IEEE International Conference on Industrial Technology (ICIT), 2016, pp. 134--140.

Abstract:
This paper presents a comparison between a continuous time domain approach (CTD) and a discrete time domain approach (DTD) for parameter identification of induction machines P{\textgreater}100 kW fed with a voltage source inverter (VSI). The machine parameters are identified off-line, based on the reference voltage and the measured current at standstill and single-axis excitation by the VSI. The quality of the identified parameters is verified with the comparison of measured and estimated torque for the whole operating range, exclusively the field weakening region.

186.

S. Gruber, "Analyse und Optimierung eines tubularen Linearmotors in Sonderbauform für hydraulisch betätigte Kupplungs-Brems-Kombinationen", {Bergische Universität Wuppertal}, 2016.

185.

J. Holtz, G. da Cunha, N. Petry and P. J. Torri, "Control of Large Salient-Pole Synchronous Machines Using Synchronous Optimal Pulsewidth Modulation", IEEE Transactions on Industrial Electronics, vol. 62, no. 6, pp. 3372--3379, 2015.

Abstract:
High-power grinding mills are used in the cement and mining industries to crush clinker or copper ore and grind these materials to fine powder. The multimegawatt speed-controlled mill drives operate at a very low angular speed. Synchronous motors with a high number of pole pairs are used as the prime movers. They are traditionally fed by load-commutated thyristorized cycloconverters. These are prone to failure modes that can lead to excessive torque pulsations and high overcurrents. The huge stator, which was built as a separate ring-shaped structure around the tubular mill, may then get mechanically displaced, and the operation of the plant is interrupted. A novel and reliable direct drive uses a voltage source inverter that operates at the unity power factor for increased efficiency. Synchronous optimal pulsewidth modulation ensures a low harmonic current distortion and reduced switching losses at a very low switching frequency. The optimization of the pulse patterns takes the anisotropic magnetic properties of a separately excited synchronous motor into account. The implementation in a 23-MW semiautonomous grinding mill installed in a Zambian copper mine is intended.

184.

S. Gruber, R. Wegener and S. Soter, "Design Process for High Force Tubular Linear Drive with DiscreteWound Coils" in The 10th International Symposium on Linear Drives for Industry Applications, 2015.

183.

A. Uphues, K. Nötzold, R. Griessel, R. Wegener and S. Soter, "Overview of LVRT-capability pre-evaluation with an inverter based test bench" in 2015 IEEE 24th International Symposium on Industrial Electronics (ISIE), 2015, pp. 748--753.

Abstract:
With increased renewable power penetration level the system operators of power grids require low-voltage ride-through (LVRT) capability of renewable power plants. The LVRT-capability has to be verified during the process of certification with precisely defined short circuit tests on a reactance based test bench. For the development of the fault ride through (FRT) capability the cost intensive reactance based test configuration is replaced by an inverter based voltage sag generator (VSG). This paper deals with an overview of the whole inverter based test configuration including the control structure of the grid emulator and the adjustment of the grid side converter's control structure to reach LVRT-capability as well as measurement results for the pre-evaluation.