Control method of high-order LCLCL direct-current converter

Abstract

The invention provides a control method of a high-order LCLCL direct-current converter. The method comprises the following steps: carrying out the circuit conversion of the high-order LCLCL direct-current converter, and obtaining an equivalent circuit and a corresponding nonlinear time-varying equation; introducing an extended description function into the nonlinear time-varying equation to obtain an extended description time-varying equation, and performing harmonic approximation to obtain a steady-state working point equation of the nonlinear time-varying equation; adding disturbance to the steady-state working point equation to obtain a small-signal steady-state working point equation; linearizing the small-signal steady-state working point equation to obtain a harmonic equation; and establishing a state space model by the harmonic equation, and further obtaining a small signal model. The compensator is designed for the small-signal model so as to realize compensation control of the converter.

Description

Technical field [0001] The present invention belongs to the technical field of DC power converters, and more particularly to control methods for high-order LCLCL DC converters. Background technique [0002] In the field of DC / DC power converters, the power density and efficiency of the power supply is two important indicators to evaluate its performance, and improve the switching frequency of the converter to increase the efficiency of the switching power supply, but due to the rise of the switching frequency, the switching loss is greatly Increase, the efficiency also decreases with the increase in frequency, and therefore, high-frequency DC / DC power converters use LC resonance to implement soft switches operating state, thereby eliminating switch loss and improves power converters. Work efficiency. At present, the application of the LLC high-frequency resonant converter is very extensive, but its efficiency has not reached the optimal level, and the sensitivity of the high-...

AI Technical Summary

Problems solved by technology

[0002] In the field of DC / DC power converters, the power density and efficiency of the power supply are two important indicators for evaluating its performance. Increasing the switching frequency of the converter can improve the efficiency of the switching power supply, but the switching loss is greatly increased due to the increase of the switching frequency. As the frequency increases, its efficiency will also decrease significantly with the increase of frequency. Therefore, high-frequency DC / DC power converters mostly use LC resonance to realize the working state of soft switching, thereby eliminating switching losses and improving the efficiency of power converters. work efficiency

At present, LLC high-frequency resonant converters are widely used, but their efficiency has not yet reached the optimal level, and their sensitivity to high-frequency frequencies is relatively poor, which affects their ability to adjust to fluctuations in input voltage and load resistance. certain room for improvement

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