CVFR Power Supply for Aircraft Induction Machines
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Solution Overview
Problem
The increasing use of variable frequency electrical networks in aircraft systems reduces the maximum mechanical torque output of induction machines, leading to inefficiency and reliability issues when trying to supply power to these machines without adding mass or using power electronics.
Innovation Solution
A device and method utilizing a Constant Voltage and Frequency Ratio (CVFR) source, such as a Permanent Magnet Alternator or VFG Generator, to power induction machines, maintaining a constant torque over a wide frequency range by varying voltage and frequency in a constant ratio, and incorporating an induction regulator with an angular position regulation loop to ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If variable frequency power supply is used to simplify electrical power generation systems, then system reliability and simplification are improved, but the maximum mechanical torque output of induction machines decreases significantly
Solution Approach 1:
The patent changes the electrical parameters by introducing a CVFR power supply that varies both voltage and frequency simultaneously, maintaining a constant V/f ratio. This allows the system to operate at variable frequencies while preserving the magnetic flux density and torque characteristics, resolving the contradiction between system simplification and torque maintenance
2Ease of operation
If static converter with two transformation stages is added to restore fixed voltage and frequency, then induction machine operation is improved, but system reliability decreases by an order of magnitude
Solution Approach 1:
The patent extracts the power electronics conversion function and replaces it with a direct CVFR power supply approach. By eliminating the static converter with its two transformation stages, the system maintains induction machine operability while significantly improving reliability by removing vulnerable electronic components from the aircraft system
3Adaptability or versatility
If constant voltage and variable frequency power supply is used, then power supply flexibility is improved, but the maximum flux in the air gap and maximum mechanical torque output decrease in very high proportions
Solution Approach 1:
The patent applies parameter changes by coupling voltage and frequency variations together through a constant V/f ratio. This allows the power supply to be flexible across different frequencies while maintaining constant magnetic flux density in the air gap, thereby preserving maximum torque output despite frequency 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 solution maintains maximum electromagnetic torque unchanged across varying frequencies, allowing for efficient and reliable operation of induction machines without increasing mass or using power electronics, while ensuring starting torque is improved and inrush current reduced.
Implementation Method 1
A CVFR type power supply according to the invention can be made using a permanent magnet alternator
Implementation Method 2
An induction machine (asynchronous motor) is an electromechanical actuator widely used in the aeronautical field
Data Source
AI summary
A device and a method for supplying electrical power to at least one induction machine on board an aircraft. This device includes at least one CVFR type source, in which the voltage and frequency are both variable but in a constant ratio, that supplies power to at least one induction machine.