Energy storage system realizing bidirectional electric energy flow and control method thereof

Abstract

The invention discloses an energy storage system realizing bidirectional electric energy flow and a control method thereof, belonging to the technical fields of electric energy conversion and storage systems and control methods thereof. The invention aims to satisfy efficient energy conversion and storage in the energy storage system realizing bidirectional electric energy flow, combines series-parallel connection switching technology of the super-capacitor and the optically designed bidirectional direct-current power inverter, realizes design of the variable voltage system adopting low voltage grade power source for power supply, reduces the volume of the power supply and saves the cost, and the power supply voltage and the system voltage can change independently, and the bidirectional direct-current power inverter with topological structure being optimally designed solves the problems of big volume of the inductor in the power inverter, high cost and high loss and is especially suitable for the occasions with instantaneous power feedback energy, and the voltage ratio of the power inverter is controlled within 2 by the novel series-parallel connection switching technology of the super-capacitor, thus being conductive to controlling the inverter and improving the efficiency of the inverter.

Description

technical field [0001] The invention belongs to an electric energy storage system, in particular to an energy storage system with bidirectional flow of electric energy and a control method thereof. Background technique [0002] In hybrid vehicles, electric vehicles, etc., where the motor is used as the power system and the two-way flow of electric energy is required, when the motor works in electric mode, the power supply provides energy to the motor, and when the motor works in power generation mode, the power supply recovers the energy generated by the motor. Energy, in the process of energy transfer in two directions, it is necessary to realize energy transformation and storage, and the energy storage system plays a key role. [0003] In the past, such an energy storage system with two-way flow of electric energy is known, that is, a high-voltage power supply is used to realize the two-way flow of energy through the transformation of voltage and flow of the power converte...

AI Technical Summary

Problems solved by technology

[0004] In the above-mentioned energy storage system with two-way flow of electric energy, the power supply is large in size and high in cost; when the motor runs electrically and the required voltage increases to a value greater than the voltage of the power supply, the voltage value of the power supply must be increased; the switch that constitutes the power converter The tube voltage / current level is large and the loss is large, resulting in low efficiency of the device; when the motor’s own inductance is used to boost the feedback energy, the motor’s inductance loss is large. In practice, the boost has a certain transformation ratio, and the back electromotive force and the power supply voltage value are between This method can only be used within a certain ratio, which limits the range of voltage variation; when the motor is generating electricity and the speed is relatively low, the counter electromotive force is very small, and energy cannot be recovered, making the energy recovery efficiency low

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