Supercapacitor Charging Device with Impedance Compensation
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Solution Overview
Problem
The existing charging devices for supercapacitors are inefficient due to their failure to account for internal voltage drops, leading to prolonged charging periods and reduced efficiency.
Innovation Solution
A charging device comprising a DC to DC converter, an adjustable voltage divider, and a controller that senses the supercapacitor voltage, determines a target voltage exceeding the nominal voltage to compensate for internal impedance, and adjusts impedance values during charging phases to efficiently charge the supercapacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to set supercapacitor voltage to nominal voltage, then voltage control is achieved, but charging time is dramatically lengthened due to internal voltage drop not being accounted for
Solution Approach 1:
The charging device calculates and applies a voltage compensation value in advance based on the supercapacitor's internal impedance and expected charging current. This preliminary action anticipates the internal voltage drop and pre-adjusts the target voltage, allowing the feedback control to achieve accurate voltage control without the delay caused by reacting to voltage drops after they occur.
Solution Approach 2:
The invention dynamically changes the target voltage parameter by adding a compensation value that accounts for internal impedance effects. Instead of using a fixed nominal voltage as the target, the system adjusts the target voltage based on real-time parameters (internal impedance, charging current), transforming the control approach to account for the supercapacitor's non-ideal characteristics and thereby reducing charging time while maintaining accuracy.
2Device complexity
If feedback control ignores internal impedance, then control simplicity is maintained, but charging efficiency is dramatically reduced
Solution Approach 1:
The invention introduces an intermediary compensation mechanism that bridges the gap between the simple feedback control and the supercapacitor's internal impedance effects. The compensation value acts as an intermediary parameter that translates the internal impedance characteristics into a voltage adjustment, allowing the simple feedback control structure to achieve high charging efficiency without requiring complex control algorithms or additional hardware.
3Manufacturing precision
If target voltage equals nominal voltage, then charging stops at nominal voltage, but actual stored voltage is lower due to internal voltage drop
Solution Approach 1:
The compensation value acts as a counterweight to the internal voltage drop. By adding this compensatory voltage component to the nominal voltage target, the system balances out the negative effect of internal impedance. The extra voltage applied through the compensation mechanism counteracts the voltage that will be lost internally, ensuring that the supercapacitor actually reaches the desired voltage level without wasting energy on prolonged charging.
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 significantly reduces charging time and improves efficiency by accounting for internal voltage drops, ensuring the supercapacitor reaches the desired voltage level effectively.
Implementation Method 1
A charging device comprising a DC to DC converter
Implementation Method 2
an adjustable voltage divider
Data Source
AI summary
A charging device that includes (a) a DC to DC converter (“converter”) that includes a converter control input and a converter output for outputting a charging voltage to the supercapacitor, (b) an adjustable voltage divider, (c) a controller that is configured to (i) sense a supercapacitor voltage, (ii) determine a first target value of the supercapacitor voltage, based on an internal impedance of the supercapacitor and on a nominal supercapacitor voltage that is lower than the first target value of the supercapacitor voltage, and (iii) during a first phase of a charging process, output a control signal via the control output and to the converter control input, to set the charging voltage to one or more values that once provided to the supercapacitor cause the supercapacitor voltage to reach, at the end of the first phase of the charging process, the first target value of the supercapacitor voltage.