Stator Winding Wave Pattern Reduces Switch Complexity
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Solution Overview
Problem
Existing stator windings for electric generators face challenges in efficiently converting electrical frequency while maintaining mechanical frequency, leading to issues with symmetry, increased current, and asymmetrical currents due to the need for multiple bidirectional switches and long conductors, which complicates the design and reduces reliability.
Innovation Solution
A wave winding scheme is introduced, where Z-shaped stator bars connect opposite parts in series, reducing the need for long conductors and bidirectional switches, and ensuring coils on opposite sides carry the same current, eliminating the need for thyristors and minimizing eddy currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a polygonal winding with multiple bidirectional switches is used for AC/AC conversion, then frequency conversion capability is improved, but device complexity and reliability deteriorate due to the large number of switches and long conductors
Solution Approach 1:
The patent extracts and eliminates the bidirectional switches from the system by implementing a direct wave winding connection. The stator bars are connected directly in series through the wave winding structure, removing the need for external switching devices and long conductors that were previously required for AC/AC conversion.
Solution Approach 2:
The patent merges the functions of frequency conversion and stator winding into a unified wave winding structure. The wave winding itself provides the frequency conversion capability through its symmetrical connection pattern, eliminating the need for separate bidirectional switches and long conductors.
2Adaptability or versatility
If bidirectional switches and long conductors are used to connect opposite parts of the winding, then frequency conversion is enabled, but asymmetrical currents and eddy currents increase
Solution Approach 1:
The patent applies asymmetry principle by creating a symmetrical wave winding structure that inherently balances the currents. The wave winding connects opposite stator bars in a symmetrical pattern, ensuring that currents flowing through opposite parts of the winding are equal and opposite, thereby eliminating asymmetrical currents and reducing eddy currents.
3Device complexity
If the number of bidirectional switches is reduced, then device complexity is reduced, but the ability to handle asymmetrical currents worsens
Solution Approach 1:
The wave winding structure is self-balancing and automatically handles current symmetry without requiring external control switches. The inherent symmetrical connection pattern of the wave winding ensures that asymmetrical currents are naturally prevented, making the system self-sufficient in maintaining current balance.
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 wave winding arrangement simplifies the stator design, reduces the number of long conductors required, and enhances reliability by directly connecting series-connected stator bars, thereby reducing the complexity and issues associated with bidirectional switches and asymmetrical currents.
Implementation Method 1
The rotor turns at a frequency where P is the number of poles of the machine and f el is the electrical frequency of the network. Electric generators are typically synchronous machines
Implementation Method 2
minimizing eddy currents
Data Source
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AI summary
Apparatus for producing electrical power from mechanical power, comprising an electric generator with a rotor and with a stator, the electric generator is configured for conversion of mechanical power into a polyphase alternating current, with the polyphase alternating current having more than three phases, with the stator having a stator core with a stator bore (109), with the stator core providing a plurality of stator slots (53-106) arranged at a distance from one another, with a plurality of coil portions inserted in the stator slots (53-106) and the coil portions are connected to form coils, wherein the coils comprises a plurality of Z-shaped portions and are laid out in a wave pattern.