Li-Po Battery Charger Based on the Constant Current/Voltage Parallel Resonant Converter Operating in ZVS

This paper discusses and presents the implementation of a boost converter as power electronic interface to be used with the thermoelectric generator (TEG). The common application for such system is the battery charger. The boundary conditions for battery chargers include the charging current and battery voltage limits which have to be respected throughout the charging process, while the maximization of the power generated from the TEG is a global target that is desired to be met as much as possible. Coordinated control algorithm that collectively combines these constraints is the main focus of this work. Novel global control algorithm is proposed and verified in this paper with detailed analysis that shows the effectiveness of the proposed algorithm. Dual control loops for the voltage and current of the boost converter will be designed and analyzed to satisfy the source and load demands. Maximum power point tracking (MPPT) mode, power matching mode and voltage stabilization mode will be integrated in the control algorithm of the battery charger. This paper puts a schematic design for a system that harvests energy from a thermoelectric generator bank of a TEG1-12611-6.0 TEG modules in order to charge a battery bank of Samsung ICR18650 Batteries using constant current (CC) and constant voltage (CV) charging profiles.

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Reevaluation of Performance of Electric Double-layer Capacitors from Constant-current Charge/Discharge and Cyclic Voltammetry

Scientific Reports ◽

10.1038/srep38568 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 76

Author(s):

Anis Allagui ◽

Todd J. Freeborn ◽

Ahmed S. Elwakil ◽

Brent J. Maundy

Keyword(s):

Cyclic Voltammetry ◽

Double Layer ◽

Time Domain ◽

Electric Double Layer ◽

Constant Current ◽

Step Response ◽

Current Voltage ◽

The Time Domain ◽

Double Layer Capacitors ◽

Electric Double Layer Capacitors

Abstract The electric characteristics of electric-double layer capacitors (EDLCs) are determined by their capacitance which is usually measured in the time domain from constant-current charging/discharging and cyclic voltammetry tests, and from the frequency domain using nonlinear least-squares fitting of spectral impedance. The time-voltage and current-voltage profiles from the first two techniques are commonly treated by assuming ideal S s C behavior in spite of the nonlinear response of the device, which in turn provides inaccurate values for its characteristic metrics. In this paper we revisit the calculation of capacitance, power and energy of EDLCs from the time domain constant-current step response and linear voltage waveform, under the assumption that the device behaves as an equivalent fractional-order circuit consisting of a resistance R s in series with a constant phase element (CPE(Q, α), with Q being a pseudocapacitance and α a dispersion coefficient). In particular, we show with the derived (R s , Q, α)-based expressions, that the corresponding nonlinear effects in voltage-time and current-voltage can be encompassed through nonlinear terms function of the coefficient α, which is not possible with the classical R s C model. We validate our formulae with the experimental measurements of different EDLCs.

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