Supercapacitor Control for Micro-Hybrid Systems
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Solution Overview
Problem
In motor vehicle micro-hybrid systems, existing technologies face challenges in effectively managing the voltage and temperature of supercapacitor energy storage units, leading to potential voltage breakdowns, premature aging, and impaired performance due to disparities in rated values and capacity, which affects the reliability and lifespan of the units.
Innovation Solution
A method of controlling a supercapacitor energy storage unit that utilizes information on its internal status, including maximum elementary voltage and temperature, to limit the availability of functions such as regenerative braking and torque assistance when thresholds are reached, and provides user warnings for potential prohibitions, ensuring optimal operation and extending the unit's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If supercapacitors are assembled in series to support high voltage values, then the voltage capability is improved, but the disparity in rated values and capacity among cells increases, requiring complex electronic balancing circuits
Solution Approach 1:
The patent changes the operating parameters of supercapacitors by defining specific voltage thresholds (first voltage threshold and second voltage threshold) and temperature thresholds. The control method monitors these parameters and limits function availability when thresholds are reached, thereby managing the series-connected cells without requiring complex balancing circuits while maintaining voltage capability.
2Reliability
If electronic balancing circuits are introduced to protect supercapacitors from overcharging, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback-based control method where the microcontroller continuously monitors the voltage of each supercapacitor cell and the temperature. When the voltage of any cell reaches the first voltage threshold for a predetermined duration or when temperature reaches the temperature threshold, the system provides feedback by limiting the availability of functions (regenerative braking, torque assistance, automatic stop-restart). This feedback mechanism protects the supercapacitors without requiring additional balancing circuits.
3Duration of action of stationary object
If function availability is limited when voltage or temperature thresholds are reached, then the lifespan of supercapacitors is extended, but the performance of the micro-hybrid system is reduced
Solution Approach 1:
The patent applies preliminary anti-action by proactively limiting function availability before voltage breakdown or excessive temperature damage can occur. When the voltage of any cell approaches the first voltage threshold or temperature approaches the temperature threshold, the system preemptively restricts functions that would otherwise charge the supercapacitors further. This prevents harmful conditions while maintaining system performance within safe operating parameters.
Solution Approach 2:
The patent makes the system dynamic by adjusting function availability based on real-time voltage and temperature conditions. The microcontroller continuously monitors the state of supercapacitor cells and dynamically enables or disables functions (regenerative braking, torque assistance, automatic stop-restart) according to the current operating conditions. This dynamic adaptation allows the system to maintain optimal performance when conditions permit while protecting the supercapacitors when thresholds are approached.
Data Source
AI summary
A method of controlling a supercapacitor energy storage unit (12), included in a motor vehicle micro-hybrid system, is disclosed. The storage unit is suitable for performing the functions of an alternator, starter and automatic stop-restart of the vehicle heat engine, regenerative braking and torque assistance. The energy storage unit (12) is a plurality of supercapacitor elementary cells connected in series (C1 to C10) and capable of delivering information (Vmax, Temp and DeltaV) on its internal status. The method includes various stages of: comparing a maximum elementary voltage (Vmax) with a first voltage threshold (Vmax1); comparing a temperature (Temp) with at least one temperature threshold (ST1=55° C., ST2=65° C. and ST3=70° C.); and, deciding on limitations of the availability of functions of the unit when the (Vmax) information reaches threshold (Vmax1) for a predetermined duration (T) and/or when the (Temp) information reaches the temperature threshold (ST1=55° C., ST2=65° C. and ST3=70° C.).