Bidirectional BUCK-BOOST circuit and method based on battery charging and discharging

Abstract

The invention provides a bidirectional BUCK-BOOST circuit based on battery charging and discharging and a working method thereof, which are suitable for a high-voltage energy storage scheme, a port 1 of a switch tube S1 is connected to a positive electrode of a battery, a port 2 of the switch tube S1 is connected to a port 2 of a switch tube S4 after being connected to a Hall sensor CT1 and a power inductor L1, the port 2 of the switch tube S1 is further connected to a port 1 of a switch tube S2, the port 2 of the switch tube S4 is further connected to the port 1 of the switch tube S3, the port 1 of the switch tube S4 is connected to one end of the direct-current bus capacitor CBUS, the other end of the direct-current bus capacitor CBUS, the port 2 of the switch tube S3 and the port 2 of the switch tube S2 are connected to the negative electrode of the battery, a switch K1 is connected between the port 1 and the port 2 of the switch tube S1 in parallel, a switch K2 is connected between the port 1 and the port 2 of the switch tube S4 in parallel, a resistor R1 and a switch K3 are connected in parallel between the port 1 and the port 2 of the switch tube S4.

Description

technical field [0001] The invention and the power electronics industry particularly relate to a bidirectional BUCK-BOOST circuit and method based on battery charging and discharging. Background technique [0002] In the application of charge and discharge control of energy storage batteries, the buck-boost circuit based on dual tubes is the mainstream power topology of high-voltage energy storage systems on the market. This BUCK-BOOST circuit has the advantages of simple structure and control. However, based on the dual-tube BUCK-BOOST circuit, there are also some defects in practical applications, which cause certain limitations in practical use. [0003] 1) From the perspective of energy flow, whether it is battery charging or discharging mode, this dual-tube BUCK-BOOST circuit can only realize one of the functions of boosting or stepping down, and is not a bidirectional BUCK in the true sense -BOOST topology. This defect will limit the input voltage range of the energ...

AI Technical Summary

Problems solved by technology

This defect will limit the input voltage range of the energy storage battery and is not suitable for integration into higher voltage energy storage solutions

[0004] 2) The rear stage of the BUCK-BOOST circuit is generally an inverter circuit. At present, the output DC bus voltage of the dual-tube BUCK-BOOST circuit scheme is generally higher than the input battery high voltage, so the system has a high voltage when the high-voltage battery is input (usually a 500V system). Application Scenarios of Busbar Stress

This will cause the defects of high voltage stress and large switching loss of the switching device of the BUCK-BOOST circuit and the switching device of the subsequent inverter circuit, thereby reducing the system efficiency and reliability

[0005] 3) The current mainstream dual-tube BUCK-BOOST circuit topology, the battery discharge mode works in BOOST mode, so the input voltage of the energy storage battery cannot achieve higher voltage integration

This will make the energy storage battery have a larger current when charging and discharging, which will increase the difficulty of internal thermal management of the battery and affect the reliability of the battery to a certain extent.

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