Wide voltage range high efficiency high frequency isolated battery charging and discharging circuit and its control method

Abstract

The invention provides a wide-voltage-range high-efficiency high-frequency isolated battery charge-discharge circuit and a control method thereof. The wide-voltage-range high-efficiency high-frequency isolated battery charge-discharge circuit comprises a transformer, and a primary circuit and a secondary circuit of the transformer, the primary circuit can be a half-bridge circuit, a full bridge circuit or a push-pull circuit, because the current can be adjusted regardless of the magnitude of the battery voltage, the battery can generate a needed discharge current under a very low voltage or even zero voltage, and charge-discharge integrated control of the battery in a wide voltage range can be achieved. Furthermore, soft switching of a main circuit can be achieved, zero-current turning off and zero-current turning on of a switch tube can be achieved, and a voltage spike generated by a secondary side switch tube of the transformer due to that the current is forced to be turned off can be eliminated with no need of an absorption circuit at the same time. By employing soft switching and removing the absorption circuit, loss of the main circuit can be reduced, and the efficiency of a charge and discharge power supply of the battery can be improved.

Description

technical field [0001] The invention relates to a charging and discharging circuit and a control strategy for a battery in the process of battery formation, in particular to a charging and discharging circuit and a control method for a wide voltage range high-efficiency high-frequency isolated battery. Background technique [0002] As represented by electric vehicles, large-capacity batteries have been widely used in national defense, transportation, industry, information technology and other fields, which put forward higher requirements for battery performance and battery charging and discharging technology. The storage battery will meet the huge opportunity. [0003] As a key process in the battery manufacturing process, battery formation technology is accompanied by battery technology. Battery formation technology is the process of converting the plate into a positive and negative plate with electrochemical characteristics under the action of chemical and electrochemical...

AI Technical Summary

Problems solved by technology

[0008] During the battery discharge process, the existing charging and discharging circuit is essentially equivalent to a Boost converter, that is, the inductive energy storage is controlled by the battery voltage on the secondary side of the transformer. When the battery voltage is low and the primary side voltage and turn ratio are constant , the required step-up ratio is quite high, and the circuit will not work normally due to factors such as the conduction voltage drop of the switch tube and the inductance resistance, and cannot meet the discharge requirements of some types of batteries; during the battery discharge process, the secondary switch tube of the transformer is turned off There will be a large voltage peak when it is off, and it is often necessary to add an absorption circuit in the circuit to reduce this voltage peak and increase the loss of the circuit; moreover, most of the main circuit switching tubes of the current charging and discharging circuit are in a hard switching state, and the switching When the frequency is high, the switching loss is large, and the system efficiency is low

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