Doubly Stator-Fed Synchronous Generator Design
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Solution Overview
Problem
Contemporary generators, such as aircraft generators, face limitations in performance due to their reliance on wound-field synchronous generators with brushless exciters and permanent magnet sub-excitors, which struggle with speed fluctuations and fast voltage disconnection in failure modes like armature winding inter-turn short circuits.
Innovation Solution
A brushless synchronous generator design featuring a rotor with magnetic flux barriers and a three-phase winding, along with an excitation winding, that operates using a doubly-fed alternating current system with a controlled rectifier and microcontroller for stable field excitation, allowing for adjustable field excitation current and efficient energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wound-field synchronous generator with brushless exciter and permanent magnet sub-exciter is used, then voltage control capability is improved, but device complexity and reliability deteriorate due to multiple excitation systems
Solution Approach 1:
The patent extracts and eliminates the complex brushless exciter and permanent magnet sub-exciter systems from the generator structure. By removing these separate excitation systems and using only stator windings for both power generation and field excitation, the design simplifies the overall structure while maintaining voltage control capability through the doubly-fed configuration.
Solution Approach 2:
The stator windings serve dual functions: generating power and providing field excitation. The doubly-fed configuration allows the same stator windings to interact with both the rotor magnetic field for power generation and the excitation winding for field control, eliminating the need for separate excitation systems.
2Ease of operation
If wound-field synchronous generator with brushless exciter is used, then voltage control is achieved, but reliability deteriorates in failure modes like armature winding inter-turn short circuit
Solution Approach 1:
The microcontroller monitors the generator's operational status and provides feedback control. When detecting failure modes such as armature winding inter-turn short circuits, the microcontroller can rapidly respond by controlling the excitation winding to maintain stable operation or safely disconnect the field excitation, improving reliability through active monitoring and response.
Solution Approach 2:
The design incorporates protective measures in advance by enabling the microcontroller to detect potential failures and take preventive actions. The ability to safely disconnect field excitation during failures is prepared beforehand, preventing catastrophic damage and maintaining system reliability.
3Adaptability or versatility
If speed fluctuations occur in contemporary generators, then adaptability is improved, but output voltage stability deteriorates
Solution Approach 1:
The microcontroller implements feedback control by continuously monitoring the generator's operating conditions and adjusting the excitation winding current accordingly. This active control compensates for speed fluctuations and maintains stable output voltage, resolving the contradiction between speed adaptability and voltage stability.
Solution Approach 2:
The doubly-fed configuration with controlled rectifier and microcontroller creates a dynamic control system that can adapt to varying speeds. The system dynamically adjusts the field excitation to maintain optimal performance across different operating conditions, ensuring voltage stability despite speed variations.
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 provides high reliability, efficient energy conversion, stable output voltage, and regulated reactive power, with the ability to prevent over-excitation and under-excitation, and safely disconnect field excitation during failures to protect electrical systems.
Implementation Method 1
a three-phase winding configured to produce a first magnetic field; and an excitation winding configured to produce a second magnetic field, wherein a rotation of the generator occurs in accordance with an interaction between the first and second magnetic fields
Implementation Method 2
an excitation winding integrated into the stator and is provided with a direct current supply
Data Source
AI summary
According to an aspect of the disclosure herein, a generator is provided herein. The generator includes a rotor that further includes a plurality of slots. The generator also includes a three-phase winding configured to produce a first magnetic field and an excitation winding. The excitation winding is a material filling in the plurality of slots and produces a second magnetic field. In turn, a rotation of the generator induces alternating voltage in the stator three-phase winding and the stator excitation winding excites the magnetic flux in the rotor.