Dual Active Bridge Battery Interface for Stable DC Bus Voltage
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Solution Overview
Problem
The use of fully rated DC:DC converters in electrical storage systems for aerospace applications adds substantial weight without providing continuous power, as they often remain idle due to the intermittent nature of power delivery.
Innovation Solution
A partially rated DC:DC converter system with a dual active bridge configuration and a controller for switching operations between DC:AC converters, allowing for voltage compensation and reduced power ratings, enabling efficient power transfer and stabilization of the DC network voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fully rated DC:DC converter is used to connect the battery ESS to the DC network, then the DC network voltage can be maintained stable, but the system weight increases substantially
Solution Approach 1:
The patent applies partial action by using a partially rated DC:DC converter (e.g., 20% power rating) instead of a fully rated converter. The converter operates intermittently to provide voltage compensation when battery voltage deviates from the DC network voltage, rather than continuously handling full power. This reduces the converter's power rating and weight while maintaining voltage stability through targeted intervention.
Solution Approach 2:
The partially rated DC:DC converter acts as an intermediary between the battery ESS and the DC network. Instead of directly connecting the battery to the DC network (which would cause voltage fluctuations), the converter mediates by providing controlled voltage compensation only when needed, reducing the burden on the converter while maintaining network stability.
2Reliability
If a fully rated DC:DC converter is used, then power regulation capability is sufficient, but the converter remains idle for much of the time, creating wasteful overhead
Solution Approach 1:
The patent implements partial action by sizing the DC:DC converter at a fraction of the battery ESS power rating (e.g., 20%). The converter provides adequate power regulation capability for voltage compensation purposes while accepting that it will operate intermittently rather than continuously. This matches the converter's capacity to the actual regulation needs rather than the maximum possible power transfer.
Solution Approach 2:
The system allows the battery ESS to directly serve the DC network without requiring a fully rated converter for continuous power transfer. The partially rated converter supplements the direct connection by providing voltage compensation when needed, allowing the system to self-regulate to the extent possible without heavy converter intervention.
3Device complexity
If the battery is connected directly to the DC network, then the system is simpler, but the DC network voltage varies by up to 20%, requiring all loads to operate with variable supply voltage
Solution Approach 1:
The patent introduces a partially rated DC:DC converter as an intermediary between the battery and DC network. This intermediary provides controlled voltage compensation to stabilize the DC network voltage while keeping the overall system relatively simple. The converter intervenes only when voltage stabilization is needed, rather than requiring complex control systems or redesigning all loads to handle variable voltage.
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 reduces the overall weight and cost of the electrical power system while maintaining rated power, providing stable DC voltage and efficient power transfer, and minimizing energy losses through reduced semiconductor ratings and advanced switching techniques.
Implementation Method 1
a DC:DC converter having first and second DC:AC converters and a transformer connected between the first and second DC:AC converters
Data Source
AI summary
The disclosure relates to an electrical power system for providing a stabilised DC voltage to a power bus. Example embodiments include an electrical power system comprising: a DC power bus having first and second DC power bus terminals; an electrical storage unit having first and second terminals, the second terminal connected to the second DC power bus terminal; a DC:DC converter having first and second DC:AC converters and a transformer connected between the first and second DC:AC converters, the first DC:AC converter connected between the first terminal of the electrical storage unit and the first DC power bus terminal; and a controller connected to control a switching operation of one or both of the first and second DC:AC converters.