Virtual Capacitor Emulating Shunt via Bi-directional Current Source
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Solution Overview
Problem
Conventional power distribution systems struggle to maintain well-regulated voltages in the presence of dynamic loads due to the large and heavy shunt capacitors required to filter transients and fluctuations, which are not feasible in space-constrained applications like ships, planes, and satellites.
Innovation Solution
A virtual capacitor system that employs a physical capacitor and a bi-directional current source, controlled by circuitry to emulate a shunt capacitor with a different capacitance, allowing the voltage across the physical capacitor to operate outside the bus voltage range, thereby reducing size and weight while maintaining effective filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large shunt capacitors are used to filter transients and fluctuations on the power distribution bus, then voltage regulation is improved, but the size and weight of the system increases substantially
Solution Approach 1:
The system changes the operating voltage parameter of the capacitor from the bus voltage (e.g., 400V) to a higher voltage level (e.g., 800V or 1000V) through a DC-DC converter. This parameter change allows the capacitor to store the same energy with smaller capacitance value, thereby reducing its physical size and weight while maintaining effective voltage regulation on the bus.
Solution Approach 2:
A DC-DC converter is introduced as an intermediary device between the power distribution bus and the capacitor. This converter enables the capacitor to operate at a different voltage level than the bus, decoupling the capacitor's operating parameters from the bus voltage and allowing optimization of the capacitor's size and weight independent of the bus voltage requirements.
2Reliability
If large shunt capacitors are used to filter transients and fluctuations on the power distribution bus, then voltage regulation is improved, but the space required for the capacitor increases
Solution Approach 1:
The system changes the operating voltage parameter of the capacitor from the bus voltage (e.g., 400V) to a higher voltage level (e.g., 800V or 1000V) through a DC-DC converter. This parameter change allows the capacitor to store the same energy with smaller capacitance value, thereby reducing its physical size and weight while maintaining effective voltage regulation on the bus.
Solution Approach 2:
A DC-DC converter is introduced as an intermediary device between the power distribution bus and the capacitor. This converter enables the capacitor to operate at a different voltage level than the bus, decoupling the capacitor's operating parameters from the bus voltage and allowing optimization of the capacitor's size and weight independent of the bus voltage requirements.
3Reliability
If the capacitance of the shunt capacitor is increased to effectively filter highly dynamic loads, then the filtering capability is improved, but the physical size and weight of the capacitor increases
Solution Approach 1:
The system changes the operating voltage parameter of the capacitor from the bus voltage (e.g., 400V) to a higher voltage level (e.g., 800V or 1000V) through a DC-DC converter. This parameter change allows the capacitor to store the same energy with smaller capacitance value, thereby reducing its physical size and weight while maintaining effective voltage regulation on the bus.
4Reliability
If the capacitance of the shunt capacitor is increased to effectively filter highly dynamic loads, then the filtering capability is improved, but the physical size of the capacitor increases
Solution Approach 1:
The system changes the operating voltage parameter of the capacitor from the bus voltage (e.g., 400V) to a higher voltage level (e.g., 800V or 1000V) through a DC-DC converter. This parameter change allows the capacitor to store the same energy with smaller capacitance value, thereby reducing its physical size and weight while maintaining effective voltage regulation on the bus.
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 virtual capacitor system effectively mitigates bus disturbances and reduces stress on generators by allowing a smaller, lighter physical capacitor to emulate a larger shunt capacitor, supporting dynamic loads without the space and weight constraints of traditional capacitors.
Implementation Method 1
a physical capacitor, and a bi-directional current source electrically coupled between the physical capacitor and a power distribution bus. The control circuitry may be configured to control the bi-directional current source and the physical capacitor to emulate a shunt capacitor electrically connected to the power distribution bus with a different capacitance than a capacitance of the physical capacitor by controlling a voltage across the physical capacitor to be within a physical capacitor voltage range that is different than the operating bus voltage range
Data Source
AI summary
An example virtual capacitor including processing circuitry, a physical capacitor, and a bi-directional current source is provided. The bi-directional current source may be electrically coupled between the physical capacitor and a power distribution bus. The control circuitry may be configured to control the bi-directional current source and the physical capacitor to emulate a shunt capacitor electrically connected to the power distribution bus with a different capacitance than a capacitance of the physical capacitor by controlling a voltage across the physical capacitor to be within a physical capacitor voltage range that is different than an operating bus voltage range.