Series-connection super capacitor group charging equalization circuit and equalization method thereof

Abstract

A series-connection super capacitor group charging equalization circuit belongs to the cell power supply management field. The circuit comprises a master control device FPGA containing a master control unit, a voltage comparison unit, an AD control unit and a switch control unit, an AD conversion module, a super capacitor group and a switch network. The super capacitor group comprises n series-connection super capacitor monomers. The switch network comprises series-connection switches located between the adjacent super capacitor monomers, anode switches connected to anodes of the super capacitor monomers and cathode switches connected to cathodes of the super capacitor monomers. One end of each anode switch is connected to the anode of each super capacitor monomer and the other end of each anode switch is connected together. One end of each cathode switch is connected to the cathode of each super capacitor monomer and the other end is connected together. During an equalization process of the series-connection super capacitor group charging equalization circuit, energy does not pass through other middle devices and is transferred from a monomer capacitor with a largest voltage to a monomer capacitor with a smallest voltage so that energy losses and a device quantity are reduced.

Description

technical field [0001] The invention relates to the field of battery power management, in particular to a charging equalization circuit of a series supercapacitor bank and an equalization method thereof. Background technique [0002] A supercapacitor is a new type of energy storage element that uses the principle of an electric double layer to directly store electrical energy. Its capacity generally ranges from a few farads to tens of thousands of farads. With the advantages of long life, wide operating temperature range, good low temperature performance and high reliability, it has been widely used in electric vehicles, locomotive braking energy recovery systems, low temperature starting of tanks, high-power laser weapon power systems and other fields. However, due to the low working voltage of supercapacitor cells (generally about 2.7V), in practical applications, it is usually necessary to use multiple cells in series to meet the voltage and current requirements. However...

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Problems solved by technology

Among them, the equalization speed of the switched capacitor depends on the equalized speed of all supercapacitors in series, and the energy transfer process needs to pass through other supercapacitor monomers; there are many switch tubes and inductors in the Buck / Boost converter. When the voltage difference between multiple or adjacent cells is not large, because the energy does not flow directly from the highest to the lowest, but flows step by step, it will lead to a decrease in the equalization speed and increase energy loss; there is a magnetic circuit in the DC-DC conversion with an isolation transformer Complexity, large volume, and difficult expansion of windings; the single-flying capacitance method can directly transfer energy from the highest monomer to the lowest monomer, but the capacity of the intermediate flying capacitor is limited compared with the energy storage monomer, resulting in a longer equalization time Long, and the energy will also have a certain loss through the intermediate flying capacitor

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