Synchronous Machine Single Exciter Stage Weight Reduction
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Solution Overview
Problem
Conventional synchronous machines are complex, heavy, and less reliable due to dual exciter field windings and control units, which increase cost, weight, and volume, and cause stability issues during startup due to low frequency excitation current and large field windings.
Innovation Solution
A synchronous machine design featuring a single high-frequency exciter stage with a transformer and rectifier, where the primary and secondary windings are magnetically coupled and positioned in a spaced-apart relationship, with a control unit providing a high-frequency control signal to induce a high-frequency AC output voltage for efficient operation as both a synchronous motor and generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dual exciter field windings and control units are used, then the synchronous machine can operate in both motor and generator modes, but the system becomes more complicated, heavier, and less reliable
Solution Approach 1:
The patent merges the dual exciter field windings into a single shared exciter field winding that serves both motor and generator modes. The control units are also merged into a single control unit that manages both operating modes, thereby reducing system complexity while maintaining operational versatility
Solution Approach 2:
The single exciter field winding is designed to function universally for both motor mode excitation and generator mode excitation. The control unit is programmed to perform multiple functions, controlling the field winding appropriately depending on the operating mode, thus eliminating the need for separate dedicated components
2Adaptability or versatility
If dual exciter field windings and control units are used, then the synchronous machine can operate in both motor and generator modes, but the weight and volume increase by 20 to 30%
Solution Approach 1:
By combining the two separate exciter field windings into one shared winding and merging the two control units into a single control unit, the patent eliminates the redundant weight of duplicate components, reducing the overall machine weight by 20 to 30% while preserving dual-mode operation capability
3Loss of energy
If low frequency excitation current and large field windings are used, then energy losses are avoided, but the back electromotive force is significantly affected by rotor speed causing stability problems during startup
Solution Approach 1:
The patent implements dynamic excitation frequency control where the excitation frequency is adjusted based on rotor speed conditions. During startup when rotor speed is low, the excitation frequency is increased to maintain stable back electromotive force. As rotor speed increases, the frequency is reduced to minimize energy losses, thus dynamically optimizing both stability and efficiency
Solution Approach 2:
The patent changes the excitation frequency parameter dynamically during operation. Instead of using fixed low frequency excitation, the system adjusts the frequency parameter according to operating conditions, thereby resolving the contradiction between energy efficiency and startup stability
4Loss of energy
If large field windings are used, then energy losses are avoided, but the amount and weight of expensive copper used in the windings increases substantially
Solution Approach 1:
The patent merges two separate large field windings into a single shared field winding that serves both motor and generator modes. This consolidation maintains the necessary magnetic field strength to avoid energy losses while substantially reducing the amount of copper required, thereby reducing weight and cost
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
This design simplifies the architecture, reduces weight and copper/iron usage, enhances stability and control, and improves reliability by using a single exciter section, providing better efficiency and reduced component count.
Implementation Method 1
The primary and secondary windings are spaced apart from, and magnetically coupled to, each other
Implementation Method 2
The rectifier is electrically connected to the secondary winding, is mechanically connected to the rotor, and rectifies an output of the secondary winding to provide a rectified output to the rotor
Data Source
AI summary
A synchronous machine (100) has a frame (110), a shaft (115), a main section (120), and an exciter section (125). The main section (120) has a stator winding (130) which is mounted on the frame, and a rotor winding (135) which is mounted on the shaft. The exciter section has a transformer (140) and a rectifier (145). The transformer has a primary winding (140A) mounted on the frame and a secondary winding (140B) mounted on the shaft. The rectifier is mounted on the shaft and rectifies an output of the secondary winding to provide a rectified output to the rotor. A control unit (170) provides a high-frequency control signal to the primary winding. This signal is magnetically coupled to the secondary winding, rectified, and then applied to the rotor to control the operation of the synchronous machine.