Isolation type bidirectional buck-boost converter and work method

Abstract

The invention provides an isolation type bidirectional buck-boost converter. The isolation type bidirectional buck-boost converter is characterized in that a drain electrode of a first field effect transistor is connected with a first end of a high voltage side, a source electrode of the first field effect transistor is separately connected with one end of a first capacitor and a drain electrode of a second field effect transistor, a source electrode of the second field effect transistor is connected with a second end of the high voltage side, the other end of the first capacitor is connected with a first end of a transformer, a second end of the transformer is connected with the source electrode of the second field effect transistor, a third end of the transformer is separately connected with a source electrode of a third field effect transistor and a drain electrode of a fourth field effect transistor, a drain electrode of the third field effect transistor is connected with one end of a second capacitor, the other end of the second capacitor is separately connected with a source electrode of the fourth field effect transistor and a second end of a low voltage side, and a fourth end of the transformer is connected with a first end of the low voltage side. For realizing input and output electrical isolation, the transformer is employed to realize energy transmission of the bidirectional buck-boost converter, a switch device realizes the soft switch technology, the switch loss is reduced, and conversion efficiency is improved.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to an isolated bidirectional buck-boost converter and a working method. Background technique [0002] The bidirectional DC-DC converter realizes the bidirectional transmission of energy, which is functionally equivalent to two unidirectional DC / DC converters, and is a typical "one machine with two uses" device. In applications that require bidirectional energy flow, the volume, weight and cost of the system can be greatly reduced. It has been widely used in UPS systems, aerospace power systems, electric vehicle drives and distributed power systems. Improving the efficiency of the converter, increasing the input-output voltage ratio and reducing the number of devices are the key points and difficulties in this technical field; the existing medium-power bidirectional DC / DC converter has a relatively complex structure and a large number of devices. [0003] figure 1 It is an existin...

AI Technical Summary

Problems solved by technology

The circuit consists of two asymmetrical half-bridges, which can realize the electrical isolation of the input and output terminals, but its voltage ratio It is only related to the turn ratio of the transformer. After the circuit is built, its voltage becomes relatively low and cannot be changed, and the control is not flexible

At the same time, the circuit can only adjust the power of the circuit through phase-shift control technology, and the control algorithm is complicated

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