A five-degree-of-freedom modulation method for dual active bridge dc-dc converters

Abstract

The invention discloses a five-degree-of-freedom modulation method of a dual active bridge DC-DC converter, the modulation method is used for a DAB converter, and the modulation method includes: S1, based on the conduction of the switch in the DAB converter Sequence and duration determine the working mode of the DAB converter; S3, take the minimum peak-to-peak value of the inductor current as the optimization goal, use the KKT condition to find the minimum peak current in each working mode, and then compare and obtain the minimum peak-to-peak value of the global current strategy, it is worth mentioning that the peak-to-peak value of the inductor current has a simple expression, which can be regarded as another form of the root mean square current, which can greatly simplify the optimization complexity; the present invention has a smaller effective value of the inductor current, almost All switching tubes can realize soft switching, which can reduce the conduction loss and turn-on loss of the DAB converter to the greatest extent; in addition, the present invention also retains the simplicity of control and is easier to implement.

Description

technical field [0001] The invention relates to the technical field of power electronic control, in particular to a five-degree-of-freedom modulation method of a dual active bridge DC-DC converter. Background technique [0002] In recent years, with the rapid development of distributed power sources and energy storage systems, the demand for bidirectional isolated converters (IBDC) is increasing; dual active full-bridge bidirectional DC / DC (DAB) converters are due to their symmetrical structure and simple control , high power density, high efficiency, and modularization have become the core topology of bidirectional isolated converters, and are widely used in power electronic transformers, electric vehicles, and battery energy storage grid-connected systems. [0003] The traditional DAB converter modulation method is phase shift modulation (PSM), which controls the direction and magnitude of the transmission power by adjusting the phase shift angle (external phase shift angl...

AI Technical Summary

Problems solved by technology

[0003] The traditional DAB converter modulation method is phase shift modulation (PSM), which controls the direction and magnitude of the transmission power by adjusting the phase shift angle (external phase shift angle) between the primary and secondary full bridges of the converter; although the PSM method is simple, But when the input and output do not match, the zero-voltage switching (ZVS) operation will be lost, thereby increasing the switching loss; in addition, a large amount of reactive power increases the RMS value of the inductor current, resulting in a higher conduction loss; therefore , its conversion efficiency decreases, especially at light load

Images