Some results of voltage increase in marine electrical propulsion installations

The main voltage parameters of marine electrical propulsion installations, at various load capacities, with further stress assessment are discussed in the article. By considering voltage options, it was revealed that an increase in inductive resistance makes it possible to manufacture a machine with high power, but the quality of electrical energy in transient modes is deteriorated. During starts, reversals, resets and load surges of powerful consumers, large voltage dips will occur on the generator. To solve the problem, including determination of optimal parameters of the generator, based on the multifactorial nature of the task of creating an electric machine for a specific purpose, an analysis of all the necessary parameters was carried out. The main dimensions of the machine depend on its full power, angular speed and electromagnetic loads. The article presents technical solutions considered using the example of a modern multipurpose icebreaker-supply “Vitus Bering”. Also, as an example, an icebreaker of the Taimyr type with a limited draft is considered, for the first time in modern practice, an alternating-changing current EDMS is used. From the experience of operating the icebreakers “Taimyr” and “Vaigach”, the transition to high voltage did not lead to a complication and increase in the complexity of the maintenance of the MPM, although it required strict compliance with safety regulations during the work. During the operation of icebreakers with MPM 6.3 kV, not a single case of single-phase short circuit or electrical injury has been recorded.

A survey of harmonics in power systems of ships with electrical propulsion drives

The number of commercial ships with electric propulsion is in continuous increase due to their versatility and fuel efficiency. Total harmonic distortion consequences on marine electrical power systems will be discussed. This paper aims to highlight the need for harmonic filter implementation on electric propulsion with static converters. For this study, a simulation in Matlab Simulink will reveal the effect of electrical filters on THD and voltage end current waveforms.

Experimental and numerical studies on small contra-rotating electrical ducted fan engines

Electrical propulsion has been identified as one of the key fields of future research within the aerospace sector. The Institute of Aeronautical Engineering at the Universität der Bundeswehr München aims to contribute to the ongoing development of small-sized electrical ducted fan engines with a thrust in the range of 100 N. A special emphasis is placed on electrically powered contra-rotating fan stages. When compared to a conventional rotor–stator stage, contra-rotating fan stages allow for a more compact design, considering a given pressure ratio, or an increased pressure ratio at a constant fan diameter. Since numerous new aircraft concepts are presently being developed, a high demand for compact and powerful electrically driven engines arises. Electrically driven contra-rotating fan engines provide a high potential in terms of compactness, emissions and efficiency. Using electric motors offers the ability to overcome common issues, such as design and integration of a contra-rotating stage into a gas turbine. An innovative new engine design featuring such a contra-rotating stage is developed and tested at one of the Institute’s test benches for electrical propulsion. Key components are two brushless motors powering the fan stage, one for each rotor. Various operation points are investigated experimentally during an extensive test campaign. Experimental results are compared to results of numerical simulations computed by ANSYS CFX. Results indicate a good agreement between experiment and simulation. The engine is running very smooth throughout all tested operation points. Yet, intensive heating up of the electric motors and high-temperature zone are found to be an issue at higher rotation speeds.

Design and analysis of double stator HE-FSM for aircraft applications

The main objective of aerospace industry is to produce all electric aircraft (AEA) equipped by electrical devices in coming developments. Electrical machines that provide higher torque densities are gaining more interest for researchers to obtain sustainable direct-drive electrical propulsion system for aircraft applications. In addition to lesser weight and higher torque density, a machine should be “fault tolerant” to applied in aerospace applications. A novel machine for high starting torque, identified as flux switching machine (FSM) was established over the last decade. FSMs comprise all effective sources on stator including robust rotor structure. These machines exhibited higher “torque-to-weight ratios” and reliability. Nonetheless, the challenge of developing a machine suitable for aircraft applications goes far beyond electromagnetic design and much deeper into the field of mechanical systems than traditional ones. Thus, a new double stator (DS) hybrid excitation (HE) FSM design employing segmented rotor is proposed and analyzed in this research work. The suggested design for DS HE-FSM comprises of six field excitation coils (FECs) and six permanent magnets (PMs) as their excitation sources. In this research, investigation of DS HE-FSM is accomplished with respect to flux linkage, back EMF, cogging torque and torque analysis based on 2D FEA.