High-step-down-ratio switched capacitor LCLCL resonant converter based on third harmonics and parameter design method

Abstract

The invention discloses a high-step-down-ratio switched capacitor LCLCL resonant converter based on third harmonics and a parameter design method. The high-step-down-ratio switched capacitor LCLCL resonant converter mainly comprises a switched capacitor bridge, a five-element resonant cavity, a transformer and a full-wave rectification module, wherein the switched capacitor bridge comprises six switching tubes and five capacitors, the switching tubes are connected in series, and two ends of every two adjacent switch tubes are connected in parallel with one capacitor; the five-element resonant cavity comprises three resonant capacitors, a resonant inductor, an excitation inductor, a notch inductor and a notch capacitor, the three resonant capacitors are connected with two flying capacitors of the switched capacitor bridge respectively, the other ends of the three resonant capacitors are connected with the resonant inductor in series, the other end of the resonant inductor is connected with the excitation inductor in series, the excitation inductor is connected with the notch inductor, and two ends of the notch inductor are also connected in parallel with two ends of the notch capacitor; and the primary side of the transformer is connected in parallel with the excitation inductor of the five-element resonant cavity, and the secondary side of the transformer is the full-wave rectification module. The converter has the capability of reducing the current loss of a rectifier diode, and can improve efficiency.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a third harmonic-based high step-down ratio switched capacitor LCLCL resonant converter and a parameter design method. Background technique [0002] In recent years, the development of renewable energy such as wind power and photovoltaic power generation has been booming, and the cost of power generation has gradually decreased, and it has gradually become an indispensable and important part of the power supply system. However, the status of renewable energy power generation is generally greatly affected by the environment and has poor stability. Therefore, the DC microgrid came into being. The output of renewable energy power generation is generally direct current, so access to direct current microgrid often only needs to be boosted by a first-stage DC-DC converter. The bus voltage of the DC microgrid is 400V, 48V, 12V, etc. Generally, a lower bus voltage is obtain...

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Problems solved by technology

[0003] (1) When the voltage ratio of the converter is high, the volume of the magnetic element increases and the efficiency decreases;

[0004] (2) The voltage input range is limited. When inputting in a wide range, it is easy to stay away from the resonance operating point and reduce the efficiency;

[0005] (3) When the circuit starts, it often brings a large surge current, which may cause circuit damage

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