High-frequency transformer delta-star connected high-gain DC converter

Abstract

The invention discloses a high-frequency transformer delta-star connected high-gain DC converter comprising six power switch tubes, an input filter capacitor, an output filter inductor, an output filter capacitor, six rectifier diodes and a high-frequency three-phase transformer, wherein a winding of the high-frequency three-phase transformer is in delta / Y connection. The invention realizes the output boosting by utilizing the intrinsic characteristics of the delta / Y connected high-frequency three-phase transformer, can achieve the high grain of output voltage by combining with the proper turn ratio of the high-frequency three-phase transformer; a primary side is a three-phase bridge type power conversion circuit, the three-phase bridge type power conversion circuit respectively dislocates phases at 120 degrees, the upper and the lower power switch tubes work complementarily and symmetrically, and the primary side bridge type circuit and a secondary side three-phase rectifier diode can realize three-phase cross parallel-connected effect so as to decrease input current ripples and output current ripples, enable the heat distribution of power devices to be equalized and enhance the reliability of the converter.

Description

technical field [0001] The invention relates to a DC-DC converter, in particular to a high-gain DC converter with delta-star connection of a high-frequency transformer. Background technique [0002] A conventional full-bridge DC-DC converter includes a high-frequency transformer, four power switch tubes, and four output rectifier diodes, the source of the first power switch tube and the drain of the second power switch tube and the high-frequency One end of the primary winding of the transformer is connected, the source of the third power switch is connected with the drain of the fourth power switch and the other end of the primary winding of the high frequency transformer, the cathode of the first diode is connected with the second diode The anode of the third diode is connected to one end of the secondary winding of the high-frequency transformer, and the cathode of the third diode is connected to the anode of the fourth diode and the other end of the secondary winding of ...

AI Technical Summary

Problems solved by technology

In recent years, some high-gain DC-DC conversion circuits have been studied successively. There are two main types: one is the push-pull forward converter, which is essentially an isolated push-pull converter. This converter is a basic step-down converter. The deformation of the full-bridge converter still needs to rely on the turn ratio of the high-frequency transformer to achieve high-gain voltage output. Due to the large leakage inductance of the transformer, there are also switching losses and reverse recovery losses similar to the full-bridge converter; another The first class is a two-stage power converter. For example, the front stage is a basic step-up converter, and the rear stage is an open-loop bridge converter. In this case, the latter stage converter is equivalent to an electronic transformer. The two-stage power converter It is possible to achieve a high-gain output voltage, but there are five power switch tubes and five output rectifier diodes in the entire conversion topology, so in the case of low-voltage input, there are still switching losses caused by leakage inductance and reverse recovery losses

Although these two types of high-gain isolated DC-DC converters achieve high-gain voltage output through a very high transformer turn ratio, the external power circuit is complicated, and the high-turn ratio transformer has a large leakage inductance, so the power cannot be reduced. The voltage stress of the switch tube and the output rectifier diode limits the further improvement of the working efficiency of the converter

Images