Dual Channel PM Generator Flux Regulation
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Solution Overview
Problem
Electrical power generation systems for aeronautical applications face challenges with weight, cost, and complexity due to the need for reduction gearboxes in wound field synchronous machines, while traditional permanent magnet machines lack means to regulate output effectively.
Innovation Solution
A dual channel power generation system using a permanent magnet dynamoelectric machine with two multiphase alternating current stators, control coils, multiphase rectifiers, current and voltage feedback loops, and load-sharing controllers to regulate magnetic flux linkage and maintain equal current values across both channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wound field synchronous machine is used to enable easy adjustment of rotor current for regulating electrical output, then output regulation capability is improved, but weight, cost, and complexity increase due to the requirement of a reduction gearbox
Solution Approach 1:
The patent replaces the mechanical reduction gearbox with an electrical control solution. Instead of mechanically adjusting rotor current through a gearbox, the invention uses control coils that generate magnetic flux to regulate the permanent magnet machine's output electrically, eliminating the mechanical transmission system and reducing weight.
Solution Approach 2:
The patent changes the regulation approach from mechanical parameter adjustment (via gearbox) to electrical parameter control (via control coil current). By varying the control coil current, the magnetic flux linkage is adjusted, which directly controls the electrical output parameters without mechanical intervention.
2Weight of moving object
If a permanent magnet machine is used to enable direct coupling to prime movers and eliminate reduction gearbox, then weight, cost, and complexity are reduced, but means to alter magnetic flux for regulating output are lacking
Solution Approach 1:
The patent introduces control coils as an intermediary element between the permanent magnets and the stator windings. These control coils generate an adjustable magnetic flux that interacts with the permanent magnet field, serving as a mediator to regulate the machine's output without compromising the direct-coupling advantage.
Solution Approach 2:
The patent segments the magnetic field generation into two independent components: the permanent magnets providing the base flux and the control coils providing the adjustable flux. This segmentation allows independent control of the magnetic flux linkage, enabling output regulation while maintaining the permanent magnet structure's weight advantages.
3Adaptability or versatility
If a regulated PM machine with control coil is used to enable magnetic flux alteration for output regulation, then output regulation capability is improved, but device complexity increases due to additional control systems
Solution Approach 1:
The patent merges the control coil system with the existing stator windings structure. The control coils are integrated into the stator assembly, sharing the same magnetic circuit and structural support, which reduces overall device complexity compared to having separate control systems.
Solution Approach 2:
The patent implements feedback control loops that automatically adjust the control coil current based on the actual electrical output. This feedback mechanism simplifies the control system by using automatic regulation rather than complex manual control, reducing the operational complexity while maintaining regulation capability.
4Reliability
If a dual channel power generation system with two stator windings is designed for system redundancy, then reliability is improved, but control complexity increases to maintain equal current distribution
Solution Approach 1:
The patent uses current feedback loops for each rectifier bus that continuously monitor the current distribution between the two channels. This feedback information is fed to the load-sharing controller, which automatically adjusts the voltage regulator reference signals to maintain equal current distribution, simplifying the control of the dual-channel system.
Solution Approach 2:
The patent introduces a load-sharing controller as an intermediary between the two independent control systems. This mediator coordinates the control signals to both channels, ensuring balanced current distribution without requiring complex direct interaction between the two control systems, thereby reducing overall control complexity.
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 configuration reduces weight, cost, and complexity by enabling direct coupling to prime movers and precise voltage regulation, ensuring equal current distribution across both channels, thereby enhancing system stability and dynamic performance.
Implementation Method 1
two multiphase alternating current stators that develop electromotive force (EMF) in response to rotation of the rotor due to the magnetic flux linkage between the rotor and the stators
Implementation Method 2
two control coils that each change the magnetic flux linkage of a respective stator in response to the level of a control current that passes through the control coil
Data Source
Figure 1
Figure 2~3
AI summary
A dual channel power generation system (2) comprises: a prime mover (4); a permanent magnet (PM) dynamoelectric machine (6) that has a PM rotor (10) coupled to the prime mover, two multiphase alternating current (AC) stators (12a, 12b) that develop electromotive force (EMF) in response to rotation of the PM rotor due to the magnetic flux linkage between the PM rotor and the stators, two control coils (14a,14b) that each change the magnetic flux linkage of a respective stator in response to the level of a control current that passes through the control coil; a multiphase AC rectifier (18a,18b) for each stator that receives AC power from its respective stator to supply DC power on a respective rectifier bus; a current feedback loop (96a,96b) for each rectifier bus; a voltage feedback loop (98a,98b) for each rectifier bus; a load-sharing controller (34) responsive to both current feedback loops to develop a voltage regulator reference signal for each rectifier bus that is representative of the value of voltage that its corresponding stator should produce to maintain equal values of current for both rectifier buses; and a voltage regulator (38a,38b) for each rectifier bus responsive to its respective voltage feedback loop and voltage regulator reference signal to produce the control current for its respective control coil that changes the magnetic flux linkage of its respective stator to maintain the value of voltage that its corresponding stator should produce to maintain equal values of current for both rectifier buses.