Generator DC Bus Fault Control via Battery Backup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electric systems for gas turbine engines, a short circuit on the DC power bus can divert power from engine accessories and prevent the voltage regulator from receiving control voltage, jeopardizing the operation of critical components like air, lube, and fuel pumps.
Innovation Solution
A control system monitors the DC bus for short circuits, disconnects affected accessories using a switch, and provides control voltage from a battery to ensure continued operation of these components until the short circuit is resolved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the DC bus and engine accessories are connected in parallel to share generated power, then power distribution efficiency is improved, but a short circuit on the DC bus can divert power from engine accessories causing them to fail
Solution Approach 1:
The electrical system is segmented into two independent circuits: a main DC bus circuit for aircraft power distribution and an accessory bus circuit for engine accessory power supply. A physical separator (insulating barrier) divides the DC bus and accessory bus into separate electrical domains, preventing fault propagation between them while maintaining independent power distribution functionality.
Solution Approach 2:
A control system acts as an intermediary between the DC bus and engine accessories. It continuously monitors the DC bus for short circuits and automatically controls a switch to disconnect accessories from the DC bus when a fault is detected, thereby protecting accessories from fault-induced power diversion while maintaining normal parallel operation during healthy conditions.
2Device complexity
If the voltage regulator receives control voltage from the DC bus, then system complexity is reduced, but during a short circuit the voltage regulator receives no control voltage causing loss of voltage control
Solution Approach 1:
The control system serves as an intermediary power source for the voltage regulator during fault conditions. It includes a switch that connects the voltage regulator to the accessory bus (which remains powered during DC bus short circuits) when a fault is detected, ensuring continuous control voltage supply without adding complex dual-power-source architecture.
Solution Approach 2:
The control system is pre-configured with knowledge of the electrical architecture and fault scenarios. It continuously monitors DC bus conditions and is ready to immediately switch the voltage regulator's power source from the DC bus to the accessory bus upon detecting a short circuit, eliminating the need for complex real-time decision-making circuits.
3Reliability
If a switch disconnects accessories from the DC bus during a short circuit, then accessory protection is improved, but device complexity increases due to additional switching control components
Solution Approach 1:
The control system performs multiple functions using a single integrated unit: it monitors DC bus voltage for short circuits, controls the switch to disconnect/ reconnect accessories based on fault detection, and manages power distribution to the voltage regulator. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The control system automatically detects DC bus short circuits and autonomously controls the switch to protect accessories without requiring external intervention or complex control algorithms. The system self-monitors and self-acts based on pre-programmed fault response logic, simplifying the control architecture.
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
Prevents power drainage from critical engine accessories during a short circuit, maintains their operation, and ensures continuous control voltage supply to the voltage regulator, thereby ensuring reliable power generation and accessory functionality.
Implementation Method 1
control voltage is delivered to the generator from a battery
Data Source
AI summary
An aircraft electrical system comprises a generator to be driven as part of a gas turbine engine. The generator supplies electrical power to a plurality of accessories associated with the gas turbine engine, and to an aircraft DC bus in parallel to the supply to the accessories. A battery supplies voltage to a control circuit for the generator through a selectively opened and closed switch. A control detects a short circuit on the aircraft DC bus. The battery switch allows power from the battery to flow to provide control voltage for the generator when the control detects a short circuit on the aircraft DC bus.