Integrated Starter-Exciter for Compact Rotating Stabilisers
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Solution Overview
Problem
Existing rotating stabilisers have a large footprint and complex construction due to the need for a separate auxiliary motor and exciter, requiring maintenance and increasing costs and noise.
Innovation Solution
An integrated starter/exciter replaces the separate auxiliary motor and exciter, functioning as both a motor during starting and an exciter during normal operation, with a power converter mounted on the rotor shaft, reducing the need for a separate auxiliary motor and simplifying the construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate auxiliary motor and exciter are used in the rotating stabiliser, then the synchronous condenser can be started and operated, but the footprint and device complexity increase significantly
Solution Approach 1:
The patent combines the auxiliary motor and exciter into a single integrated starter/exciter unit. The stator of the auxiliary motor and the stator of the exciter are merged into one common stator assembly, while the rotor of the auxiliary motor serves as the rotor for the exciter. This merging eliminates the need for separate motor and exciter components, reducing the overall footprint and construction complexity while maintaining the starting capability and excitation function.
Solution Approach 2:
The integrated starter/exciter unit performs multiple functions: it acts as an auxiliary motor to start the synchronous condenser, and simultaneously serves as an exciter to provide field current to the rotor winding. The power converter mounted on the rotor shaft also serves dual purposes by providing both starting torque control and excitation current control. This multi-functionality reduces the number of components needed in the system.
2Speed
If a separate auxiliary motor is used to rotate the rotor assembly during starting, then the synchronous condenser can reach rated speed, but the footprint area increases to more than 11 metres
Solution Approach 1:
The auxiliary motor and exciter are merged into a single integrated unit with shared stator and rotor components. The common stator assembly houses both the auxiliary motor stator winding and exciter stator winding, while the rotor contains both the auxiliary motor rotor winding and exciter rotor winding. This consolidation significantly reduces the spatial footprint compared to having separate motor and exciter installations.
Solution Approach 2:
The exciter components are nested within the auxiliary motor structure. The exciter rotor winding is positioned on the same rotor as the auxiliary motor rotor winding, and the exciter stator winding is positioned on the same stator as the auxiliary motor stator winding. This nested arrangement allows both functions to occupy the same physical space, dramatically reducing the overall footprint area.
3Ease of repair
If separate auxiliary motor and exciter are installed on separate base plates, then the components can be independently maintained, but the total footprint and construction complexity increase
Solution Approach 1:
The auxiliary motor and exciter are merged into a single integrated assembly mounted on one base plate. The common stator assembly can be accessed and maintained as a unified structure, while the rotor components remain accessible through the coupling mechanism. This merging reduces the total footprint while maintaining reasonable maintenance accessibility through the modular design of the integrated unit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a significantly smaller footprint, reduced maintenance needs, lower costs, and lower acoustic noise, while maintaining effective reactive power support for the power grid.
Implementation Method 1
a first power converter having first terminals electrically connected to the first rotor winding and second terminals electrically connected to the second rotor winding, wherein the first power converter is mounted for rotation on the rotor shaft
Implementation Method 2
the rotor winding of the rotor assembly is typically excited by a direct current (DC) current. When operating under no-load conditions and in an under-excited mode, a synchronous condenser will absorb reactive power from the power grid. This is useful when there is an excess of reactive power in the system. When operating in an over-excited mode, a synchronous condenser will supply reactive power to the power grid.
Data Source
Figure 1~2
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AI summary
A rotating stabiliser (100) is described. The rotating stabiliser (100) is electrically connectable to a power grid (200), and includes a synchronous condenser (102), a starter/exciter (116), and a power converter (126). The synchronous condenser (102) includes a stator assembly (104) with a stator winding that is electrically connectable to the power grid (200), and a rotor assembly (108) with a rotor winding. The starter/exciter (116) includes a stator assembly (118) with a stator winding and a rotor assembly (120) with a rotor winding. The rotor assemblies (108, 120) are mechanically connected by a rotor shaft (110). A power converter (122) of the starter/exciter (116) is electrically connected to the rotor windings of the synchronous condenser (100) and starter/exciter (116) and is mounted for rotation on the rotor shaft (100). The power converter (126) has first terminals (138a, 138b, 138c) electrically connectable to the power grid (200) and second terminals (140a, 140b, 140c) electrically connected to the stator winding of the starter/exciter (116).