Electro-Mechanical Converter for DC Bus Stabilization
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Solution Overview
Problem
Conventional methods for paralleling electrical generators with different rotational speeds, phases, and voltage/current values require large capacitors for DC power bus stabilization, leading to significant weight, size, and safety concerns in aerospace applications, where electrolytic capacitors are not viable due to temperature and stability limitations.
Innovation Solution
An electro-mechanical converter coupled with a power electronic converter and feedback control system that uses the stored energy of a prime mover's rotating component to stabilize electrical power on a bus, reducing the need for large capacitors by modulating torque and energy transfer between electrical and mechanical systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If large capacitors are used to stabilize DC power bus voltage, then voltage stability is improved, but weight and size increase significantly
Solution Approach 1:
An intermediary electro-mechanical converter is introduced between the generators and the DC power bus. This converter acts as a mediator that dynamically balances power fluctuations, eliminating the need for large stabilizing capacitors. The converter transforms electrical power imbalances into mechanical energy storage in the rotating component, thereby stabilizing bus voltage without requiring massive capacitor banks.
Solution Approach 2:
The system changes the operational parameters by allowing generators to operate at different rotational speeds and produce power at different frequencies. The electro-mechanical converter adapts to these varying parameters by dynamically adjusting its operation, converting power from generators with different characteristics into a stable DC output, thus maintaining voltage stability without large capacitors.
2Stability of the object's composition
If large capacitors are used to maintain steady bus voltage, then power distribution stability is improved, but device complexity and safety risks increase
Solution Approach 1:
The electro-mechanical converter serves as a sophisticated intermediary that simplifies the overall system architecture. Rather than requiring complex capacitor banks and associated safety systems, the converter provides a single integrated solution that handles power stabilization, frequency conversion, and energy buffering through its rotating component, thereby reducing device complexity while maintaining stability.
Solution Approach 2:
The converter incorporates feedback control mechanisms that continuously monitor power bus conditions and automatically adjust its operation to maintain stability. This closed-loop control eliminates the need for complex open-loop capacitor sizing calculations and safety systems, as the feedback-driven converter dynamically adapts to maintain optimal power distribution stability.
3Quantity of substance
If electrolytic capacitors are used for DC power bus stabilization, then capacitance density is improved, but operational temperature range and reliability deteriorate
Solution Approach 1:
The patent replaces the electrical capacitor-based energy storage system with a mechanical energy storage system using the rotating component of the electro-mechanical converter. This substitution eliminates the reliability issues of electrolytic capacitors in aerospace environments, as the mechanical system has no temperature-sensitive electrolyte and can operate reliably across the full aerospace temperature range without degradation.
4Reliability
If film-foil capacitors are used in aerospace applications, then operational reliability is improved, but weight and size increase significantly
Solution Approach 1:
The system replaces the entire film-foil capacitor assembly with a mechanical energy storage approach using the rotating component. The rotating mass serves as a kinetic energy buffer that provides the same stabilization function as large film-foil capacitors but with dramatically reduced weight, while maintaining the operational reliability required for aerospace applications.
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 minimizes the weight and size of capacitors required, lowers fault currents, and reduces the risk of explosions or fires, while maintaining stable electrical power distribution, allowing for more efficient and safer operation in aerospace environments.
Implementation Method 1
an electro mechanical converter associated with the rotating component of the prime mover to convert electrical rotation into electrical power and vice versa by variable applied torque
Implementation Method 2
a feed back control associated with the electrical power bus to stabilise electrical power provided on the electrical power bus by feedback to the electrical power converter in order to proportionately control electrical power to the electro-mechanical converter to alter the torque applied to the rotating component
Implementation Method 3
uses the stored energy of a prime mover's rotating component to stabilize electrical power on a bus
Data Source
AI summary
Use of a common electrical power bus to which a number of electrical power generators and consumers are coupled is well known. Typically, a high electrical capacitance is provided across the bus in order to provide stabilisation in the switching of generators and consumer devices as well as differences in the operational performances of the electrical power generators. Particularly in aerospace applications provision of high capacity electrical capacitors creates problems. By providing a feedback control and an electrical power converter take primary electrical power from an electro-mechanical converter associated with a rotating component of a prime mover, electrical power stabilisation is achieved by applying torque changes through the electromechanical converter to the rotating component of the prime mover such that stored electrical power can then be drawn as required to accommodate transients in electrical power on the bus.