A hybrid three-level dab converter current stress optimization control method under full working conditions

Abstract

The present invention relates to a hybrid three-level DAB converter full working condition current stress optimization control method, comprising the following steps: obtaining the output voltage reference value and the actual value of the DAB converter; the difference between the output voltage reference value and the actual value through the PI After the controller obtains the estimated value of the internal resistance of the DAB converter, after the parameter adaptive direct power controller, the transmission power per unit value and the voltage transmission ratio under the current load mode are obtained; based on the transmission power per unit value under the current load and The voltage transmission ratio is used to obtain the optimal steady-state current stress control parameters in the current state; it is judged whether there is a sudden change in the load power, and if there is a sudden change in the load power, the switching sequence is reconstructed to realize the optimal control of the current stress. Combining the optimization of the steady-state performance of the converter with the optimization of the dynamic performance, the dynamic response characteristics are improved on the basis of ensuring the optimization of the steady-state current stress, thereby realizing the optimal control of the current stress of the converter under the full range of working conditions.

Description

technical field [0001] The invention relates to the field of power converters, in particular to a hybrid three-level DAB converter current stress optimization control method under all working conditions. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] New energy power generation is one of the most promising energy methods to solve the global energy crisis. The characteristics of intermittent and random power generation are the main problems in the current large-scale application. Microgrid is considered to be an effective way to achieve large-scale access and control of new energy. The key equipment to realize its energy interconnection, "energy router", is a new type of power electronic transformer that combines power electronics technology with high-frequency transformers. Voltage conversion, electrical isolation, power transmission and...

AI Technical Summary

Problems solved by technology

[0006] Or in order to optimize the dynamic response characteristics of DAB, a virtual direct power control strategy is proposed. The method of this strategy can greatly improve the response speed of DAB, but only optimize the output voltage response characteristics of the converter. When the load changes suddenly, the converter A large degree of DC bias will be generated, which will increase the transient current stress of the converter and affect the stable operation of the converter;

[0007] Or propose an inductor current boundary control method to improve the converter’s response to load and reference voltage mutations, but this method not only requires complex calculations, but also requires up to 5 Hall sensors, which greatly increases the Reduced system hardware costs;

[0008] It can be seen that the power electronic transformer DAB is used as an interface converter connecting the high-voltage side DC bus and the low-voltage side DC bus. The number of isolation transformers is large, which leads to large system volume, high cost, and decreased stability. Some existing control methods are difficult to cope with all working conditions of the converter, and it is difficult to balance steady-state operation and dynamic response performance.

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