Marine propulsion – Electric drive for propelling means
Reexamination Certificate
2001-12-21
2003-07-15
Basinger, Sherman (Department: 3617)
Marine propulsion
Electric drive for propelling means
C114S14400A
Reexamination Certificate
active
06592412
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to drive and propulsion systems for ships. In particular, drive and propulsion system having a steering propeller arranged outboard, comprising an azimuth module which can rotate and has a power transmission device, and a propulsion module arranged like a pod on the azimuth module and provided with a drive motor for a propeller.
2. Discussion of the Related Art
A drive technology such as this, which is also known in practice by the expression SSP, is a ship propulsion system which can be rotated, is preferably arranged in the region of the stern of a ship, and at the same time carries out the functions of propulsion, steering and lateral thrust production. The SSP drive is furthermore distinguished by producing little drag on the ship even with the most widely differing ship hull designs, and requires no additional cooling, since this is provided by the water flowing around the drive motor in the propulsion module. Furthermore, the SSP drive has low associated usage and maintenance costs, and offers the advantage of particularly high fuel efficiency.
In the field of ship propulsion technology there is an increasing requirement with regard to the competitiveness of the individual Companies involved to shorten the development times and to reduce the production costs. However, at the same time, propulsion systems are required which can cope with the random failure of one component, so that the maneuverability and controllability of a ship are ensured once again as quickly as possible after a fault occurring in the propulsion system.
Furthermore, it is normal in ship construction for electrical and electromechanical components, such as motors, transformers, switch panels, converter stations, cooling systems or control panels, to be supplied individually by the respective manufacturers to the shipyard, in order then to be installed in the ship by the yard personnel on appropriately provided foundations, and to wired up to one another and for their operation to be tested by the yard personnel. One disadvantage in this case is the considerable logistic complexity and hence considerable cost, which is further increased by the fact that both the manufacture of the individual components and the wiring and testing of the complete system necessitates inspection by a Classification Organization for example the American Bureau of Shipping (ABS), Bureau Veritas (BV), Der Norske Veritas (DNV), Germanischer Lloyd (GL) or Lloyds Register of Shipping (LRS). The present invention is based on the object of providing a drive and propulsion system for ships, which makes it possible to achieve a comparatively high level of safety with regard to reliable maneuverability of a ship, in a comparatively cost-effective manner.
According to the invention, this object is achieved for a drive and propulsion system having the features mentioned above in that at least two steering propellers are provided, whose respective drive motor is in the form of a permanent magnetic synchronous machine, with the stator winding of the synchronous machine having three sections which are connected to a 3-phase alternating current and are connected via the power transmission device to a converter, which is arranged in the ship and is connected on the input side via converter transformers to the ship's on-board power supply system, and in that a control and regulation device, which comprises standardized assemblies in a modular form, is provided for each of the steering propellers.
A drive and propulsion system designed in such a way takes account, to a major extent, of the increasingly more stringent requirements for the reliability and safety of a ship. This is primarily due to the presence of at least two identical steering propellers with an autonomous control and regulation device, which results in homogeneous redundancy in the propulsion system. When a fault event occurs in a mechanical or electrical component of a steering propeller, there is thus at least one spare drive available, which ensures the maneuverability of the ship.
Since the drive motor is in the form of an electrical synchronous machine, a compact, lightweight construction can be achieved, as is required for arranging the drive motor in the propulsion module. The interconnection of the sections of the stator winding, as well as the converters and converter transformers, result in a three-phase synchronous motor which is operated from the ship's on-board power supply network, and which makes it possible to achieve an adequate rated rotation speed and a sufficiently high torque at the propeller for the most common ship propulsion system in the power range from 5 W to 30 MW. Furthermore, the modular construction of the control and regulation device, which is composed of standardized modules, contributes to relatively cost-effective production.
In one preferred refinement of the invention, the converter is a network-controlled 12-pulse direct converter, and is connected on its input side to the on-board 3-power supply network via three converter transformers in the form of 3-winding transformers. Firstly, a direct converter can be manufactured cost-effectively and, secondly, it is particularly suitable for operation of large three-phase motors at a low rotation speed, such as those required for ship propulsion systems.
In order to achieve the abovementioned object, the invention furthermore proposes, for a drive and propulsion system of the type mentioned initially, that the drive motor be in the form of a permanent magnet synchronous machine, with the stator winding of the synchronous machine having six sections, of which three are in each case connected to a 3-phase alternating current and, forming a subsystem, are connected via the power transmission device to a converter which is arranged on the ship and is connected on the input side via a converter transformer to the ship's on-board power supply network, and in that a control and regulation device, which comprises standardized assemblies in a modular form, is provided for each of the two subsystems.
Such a drive and propulsion system also takes account of the random failure of one component and is easy to produce economically, for the reasons mentioned above. The partial redundancy of the drive system resulting from there being only a single steering propeller in this case is achieved by means of the autonomous subsystems, which ensure that at least limited propulsion is maintained for the ship when a defect occurs.
Ship propulsion systems, in particular steering propeller propulsion systems, produce oscillations during operation which propagate through the entire ship's hull and cause vibration in it. While, in the case of diesel propulsion systems, these oscillations are caused primarily by the reciprocating pistons, it might be supposed that such oscillations would no longer occur in the case of electric motors, such as those used in particular in submarines, but which are also being increasingly used for surface ships. However, this is not the case since, in particular, even a ship's propeller represents an oscillating load for the propulsion system, to be precise because the propeller blades partly move along the skeg or propeller-shaft stay (which is fitted to the ship's hull) during their rotational movement but, in contrast, can move largely free from this stay during another part of their rotational movement. This fluctuating load torque is readjusted by the rotation speed regulator, or by the current regulator which is subordinate to it, in order to stabilize the rotation speed of the ship's screw as exactly as possible at the pre-selected rotation speed nominal value. In this case, the torque (which fluctuates at the shaft rotation speed gas multiplied by the number of blades on the propeller) is transmitted to the drive motor, and is transmitted via its housing to its anchorage, and hence to the ship's hull. Parts of the ship's structure are thus caused to oscilla
Geil Günter
Hoes Stefan
Rzadki Wolfgang
Basinger Sherman
Schiff & Hardin & Waite
Siemens Aktiengesellschaft
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