Ultracapacitor Module With Bidirectional DC/DC Bus Transient Control
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Solution Overview
Problem
Ultracapacitor modules connected to a voltage supply bus lack the ability to control current and respond to voltage transients, relying solely on natural capacitor control, which is inadequate for managing voltage fluctuations in vehicle systems.
Innovation Solution
An ultracapacitor module with a bidirectional boost/buck DC/DC converter and an electronic controller that monitors and adjusts the voltage range of the ultracapacitor cell stack to operate between 20 to 80 percent of the voltage supply bus, enabling adaptive voltage control and protection against voltage sags and spikes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a parallel DC/DC converter is added to recharge capacitors, then the ability to restore voltage is improved, but the device complexity increases
Solution Approach 1:
The DC/DC converter is designed to perform multiple functions: it can operate in boost mode to recharge ultracapacitors when bus voltage sags, and in buck mode to protect ultracapacitors from overvoltage transients. This multi-functionality resolves the contradiction by consolidating voltage restoration and protection capabilities into a single versatile device rather than requiring separate circuits for each function.
Solution Approach 2:
The system dynamically switches between boost and buck operating modes based on real-time bus voltage conditions. The electronic controller monitors voltage transients and adaptively controls the converter's operation, allowing the same hardware to optimize performance for different scenarios (voltage sag recovery vs. transient protection), thereby maintaining reliability while managing complexity through adaptive control.
2Ease of operation
If the ultracapacitor operates at the same voltage as the bus, then the control simplicity is improved, but the adaptability to voltage transients deteriorates
Solution Approach 1:
The ultracapacitor is maintained at a continuous lower voltage level (20-80% of bus voltage) rather than attempting to match the bus voltage. This continuous voltage differential enables the capacitor to continuously absorb or supply current in response to transients, providing ongoing protective action. The DC/DC converter maintains this continuous useful action by actively regulating the voltage relationship between capacitor and bus.
Solution Approach 2:
The DC/DC converter acts as an intermediary device between the ultracapacitor and the voltage supply bus. It mediates the voltage relationship by transforming the bus voltage to match the capacitor's operating range, enabling the capacitor to respond adaptively to transients without directly experiencing full bus voltage variations. This intermediary function provides both adaptability and controlled operation.
3Reliability
If adaptive voltage control is implemented, then the protection against transients is improved, but the device complexity increases
Solution Approach 1:
The electronic controller implements feedback control by continuously monitoring the voltage supply bus and adjusting the DC/DC converter's operation accordingly. When voltage transients are detected, the controller activates appropriate control modes (boost or buck) to maintain the ultracapacitor within safe voltage limits. This feedback mechanism provides effective transient protection while keeping the control system relatively simple by relying on standard control algorithms rather than complex hardware circuits.
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 effectively protects the voltage supply bus from transients, provides emergency backup power, and ensures safety integrity by actively managing voltage within a controlled range, enhancing the reliability and safety of vehicle electrical systems.
Implementation Method 1
a bidirectional boost/buck DC/DC converter, wherein the ultracapacitor cell stack and the DC/DC converter are configured to be connected in series with a voltage supply bus
Data Source
AI summary
An ultracapacitor module may include an ultracapacitor cell stack containing one or more ultracapacitor cells. An ultracapacitor module may include a bidirectional boost/buck DC/DC converter. The ultracapacitor cell stack and the DC/DC converter may be configured to be connected in series with a voltage supply bus of a vehicle. An ultracapacitor module may include a voltage sensor configured to determine an operating voltage of the voltage supply bus. An ultracapacitor module may include an electronic controller in electrical communication with the DC/DC converter and the voltage sensor. The electronic controller may be configured to control the DC/DC converter such that the ultracapacitor cell stack operates in a voltage range that is 20 to 80 percent of the operating voltage of the voltage supply bus.