An Efficiency Optimal Control Method for Two-stage Converter

Abstract

An efficiency optimization control method for a two-stage converter, which is characterized in that the intermediate bus voltage reference value Uref of the output voltage of the front-end converter is adjusted, and it is used as a control voltage, and the front-end converter is controlled by the control circuit of the front-end converter. The output voltage Ubus of the stage converter reaches the intermediate bus voltage reference value Uref; the present invention adopts the efficiency optimization control method, based on the initial intermediate bus voltage Ubus and its reference value Uref and initial efficiency η1, to set Uref+ΔU(ΔU>0 ) to adjust the intermediate bus voltage Ubus by assigning Uref to it, detect and judge whether the adjusted efficiency η2 is increased or decreased compared with the previous efficiency η1, and determine whether the next step is to continue to assign Uref+ΔU to Uref or Uref-ΔU according to the direction of efficiency increase Uref is given to adjust the bus voltage Ubus until the two-stage converter gets the best efficiency in a certain range of intermediate DC bus voltage, so as to achieve the effect of getting the best efficiency under different working conditions.

Description

technical field [0001] The invention relates to a control method for improving the working efficiency of a two-stage converter system, and is especially suitable for converters whose input or output voltage varies in a wide range. Background technique [0002] Today, when energy issues are highly valued, improving energy utilization efficiency has become an important direction of scientific research. High-frequency converters based on modern power electronics have been widely researched and applied because of their advantages of high efficiency and small size compared with traditional linear power supplies. [0003] High-frequency converters convert one AC or DC voltage into another AC or DC voltage. Its topological form is various, according to its connection structure, there are two commonly used ones: one is a single-stage converter structure, which directly converts the input AC or DC voltage into an output AC or DC voltage; the other is a two-stage converter structure....

AI Technical Summary

Problems solved by technology

With such a wide or even wider input voltage, it is difficult to optimize the efficiency of the front-end converter design, which also affects the efficiency of the entire system

In addition, for a two-stage converter with adjustable output voltage, if a fixed intermediate bus voltage U bus If the control method is not used, the working point of the post-stage converter cannot be optimized, and the system efficiency will be reduced.

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