IGBT Inverter Circuit for Aircraft Flight Control Damping
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Solution Overview
Problem
Current electrical flight control systems for aircraft mobile aerodynamic surfaces rely on electromechanical relays for damping, which have a short lifespan, are heavy, voluminous, and fail to maintain damping capacity upon failure, posing weight and space constraints.
Innovation Solution
A power supply circuit using inverter bridges with insulated-gate bipolar transistors and junction field-effect transistors, along with damping resistors, allowing for both active motor operation and passive damping modes, utilizing junction field-effect transistors for reliability and reduced mass, and a circuit breaker for overvoltage protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromechanical relay is used to connect the motor to the damping circuit, then the damping function is achieved, but the device has a short lifespan, high mass, and large volume
Solution Approach 1:
The patent replaces the electromechanical relay with an electronic switching circuit composed of insulated-gate bipolar transistors (IGBTs) and diodes. This substitution eliminates the mechanical moving parts of the relay, thereby increasing reliability and lifespan while reducing mass and volume. The IGBT-based circuit achieves the same damping function through electronic control rather than mechanical switching.
2Reliability
If an electromechanical relay is used for damping, then the damping function is provided, but the volume is not compatible with weight and space savings requirements
Solution Approach 1:
The electromechanical relay is replaced with a compact electronic circuit using IGBTs and diodes arranged in an inverter bridge configuration. This electronic solution occupies significantly less volume than the mechanical relay while maintaining the damping function, thus satisfying the aircraft's stringent space constraints.
3Reliability
If a relay is used to connect motor to damping circuit, then damping is achieved, but the relay is subject to vibrations and has random resistance to vibrations
Solution Approach 1:
The patent eliminates the mechanical relay and its vulnerable coil and contact components by using a solid-state electronic circuit. The IGBT-based switching circuit has no moving parts, making it inherently resistant to vibrations and shocks, thereby solving the vibration resistance problem while maintaining the damping function.
4Reliability
If a relay is used for damping control, then the damping circuit is complete, but the mass and volume are incompatible with aircraft design constraints
Solution Approach 1:
The electromechanical relay is replaced with a lightweight electronic switching circuit using IGBTs and diodes. This substitution dramatically reduces the mass of the damping circuit while preserving the damping function, thereby meeting the aircraft's strict weight constraints for flight control systems.
5Reliability
If all bipolar transistors are open in passive mode, then the motor windings are connected to damping resistors, but overvoltages may rise towards the network
Solution Approach 1:
The patent introduces diodes as intermediary protective elements in the circuit. These diodes are positioned to conduct overvoltages away from the DC network when the damping resistors are insufficient to absorb all the energy. The diodes act as a safety valve, redirecting excess voltage to protect the network from damage.
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 solution provides a reliable, lightweight, and efficient damping mechanism that maintains partial damping capacity even with transistor failures, ensuring effective movement control and weight savings in aircraft systems.
Implementation Method 1
A dedicated damping circuit is therefore provided between the motor and the power supply circuit to dissipate the energy produced by the latter when the latter is driven by the mobile aerodynamic surface
Data Source
Figure 1~2
AI summary
The invention relates to an electrical engine power supply circuit, including a plurality of bridge inverter arms provided with a means for connecting each arm to an engine winding, each bridge inverter arm comprising, in series, a first insulated-gate bipolar transistor and a junction field effect transistor which are linked to a control unit, the circuit including a second insulated-gate bipolar transistor mounted in series with each field effect transistor and linked to the control unit, and a damping resistor mounted in parallel with the second bipolar transistor. The invention also relates to an aircraft flight control member, comprising a mobile aerodynamic surface combined with at least one drive motor linked to such power supply circuit.