Synthesis of a scalar ACS of the valve motor rotational speed for the icebreaker's ERM with a propulsion-steering complex "Azipod"

В статье рассматриваются основные тенденции развития систем судового автоматизированного электропривода с машинами переменного тока. В частности представлены варианты реализации электропривода с использованием частотно управляемых асинхронных двигателей и синхронных двигателей с электромагнитным возбуждением. Предлагается перспективная электромеханическая система на основе вентильного двигателя для ГЭУ ледокола с движительно-рулевым комплексом «Азипод». Целью работы является исключение структурной сложности и повышения функциональных возможностей электропривода за счет применения скалярной САУ частоты вращения вентильного двигателя вместо векторной для ГЭУ. Новизна заключается в использовании подхода и представления вентильного двигателя как объекта регулирования на основе аналогии с коллекторным двигателем постоянного тока при регулировании положения его оси токосъема. В соответствии с этим анализ информационных процессов, связанных с процессами электромеханического преобразования энергии, протекающими в синхронной машине с позиционно-зависимым частотным управлением, и синтез САУ электропривода по принципу подчиненного регулирования базируются на тех подходах, которые широко используются в регулируемых электроприводах постоянного тока, обладающих наилучшими динамическими свойствами. The article discusses the main trends in the development of marine automated electric drive systems with AC machines. In particular, variants of the implementation of an electric drive using frequency-controlled asynchronous motors and synchronous motors with electromagnetic excitation are presented. A promising electromechanical system based on a valve engine for the icebreaker's ERM with the propulsion-steering system Azipod is proposed. The aim of the work is to eliminate the structural complexity and to increase the functionality of the electric drive by using a scalar ACS of the valve motor rotational speed instead of a vector one for the ERM. The novelty lies in the use of the approach and representation of the valve motor as an object of regulation based on the analogy with the collector DC motor when regulating the position of its current collection axis. Thereby, the analysis of information processes related to the processes of electromechanical energy conversion occurring in a synchronous machine with position-dependent frequency control, and the synthesis of an ACS electric drive based on the principle of subordinate regulation are based on those approaches that are widely used in regulated DC electric drives possessing the best dynamic properties.

The Silent Path: The Development of the Single Sleeve Valve Two-Stroke Engine over the Last 110 Years

At the beginning of the 20th century the operational issues of the Otto engine had not been fully resolved. The work presented here seeks to chronicle the development of one of the alternative design pathways, namely the replacement for the gas exchange mechanism of the more conventional poppet valve arrangement with that of a sleeve valve. There have been several successful engines built with these devices, which have a number of attractive features superior to poppet valves. This review moves from the initial work of Charles Knight, Peter Burt, and James McCollum, in the first decade of the 20th century, through the work of others to develop a two-stroke version of the sleeve-valve engine, which climaxed in the construction of one of the most powerful piston aeroengines ever built, the Rolls-Royce Crecy. After that period of high activity in the 1940s, there have been limited further developments. The patent efforts changed over time from design of two-stroke sleeve-drive mechanisms through to cylinder head cooling and improvements in the control of the thermal expansion of the relative components to improve durability. These documents provide a foundation for a design of an internal combustion engine with potentially high thermal efficiency.

Synthesis of a Scalar Automatic Control System of a Valve Engine with Field Control for a Rowing Electric Installation with an Azipod Propulsion and Steering System

The article deals with the main trends in the development of marine automatic AC electric drive systems. A variant of the implementation of an electric drive using an electromechanical converter of a synchronous machine with electromagnetic field excitation is presented. A promising electric drive system with a valve engine for the icebreaker's with the Azipod propulsion and steering system is proposed. The aim of the work is to eliminate the structural complexity and expand the functional capabilities of the electric drive by using a scalar automatic control system of the frequency of rotation in the two-zone control of the valve motor of the EPS. The novelty lies in the use of the approach and representation of the control object-a valve motor as an analog of a DC collector motor controlled by an armature and by a field. The analysis of control processes is directly related to the processes of electromechanical energy conversion occurring in a synchronous machine.

Providing Processing of Complex Surfaces by Cutting on Machines Equipped with a Valve Electric Drive with an Information and Measuring System

Promising methods of metal processing by cutting the surface of complex parts are considered. To ensure high productivity when processing complex surfaces on CNC machines, the tool is provided with additional high-speed complex-coordinated movements that ensure the displacement of the cutting edge relative to the cutting surface. The offset of the cutting edges relative to the cutting zone during milling reduces the temperature load on the teeth and, as a result, increases the tool’s durability. The faster the cutting edge leaves the cutting zone, the lower the heat load and the higher the wear resistance of the cutters. In this regard, it is important to increase the speed and accuracy of movements of the working bodies of the machine. To implement the required characteristics when performing technological operations, it is proposed to use an AC electric drive system based on a valve motor with vector control and an information and measurement system containing variable sensors, which has better technical, economic and mass-dimensional indicators compared to other types of electric motors. The results of computer simulation of dynamic processes of regulating the speed and torque of a valve engine that provide the required dynamic torque and acceleration are presented. It is shown that an AC electric drive based on a valve motor provides the implementation of the required speed modes.