Half-bridge LLC constant-power wide-range converter topology and circuit

Abstract

The invention discloses a half-bridge LLC constant-power wide-range converter topology and circuit, which comprises a switch unit and a half-bridge LLC converter unit, the output of a full-bridge rectifier circuit of the half-bridge LLC converter unit is connected with a filter circuit, primary LLC half-bridge converters of two converter transformers are connected in parallel or in series, and the primary LLC half-bridge converters are connected in parallel or in series. Secondary sides of two adjacent transformers are connected together through a controllable switch, and when the control switch is switched off, output rectification parts of the secondary sides of the transformers work in a parallel mode, so that the requirement of low-voltage large-current output is met; when the control switch is closed, the secondary output rectification part of the transformer works in a series mode, so that the requirement of high-voltage output is met, and the purpose of wide output voltage is achieved.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a half-bridge LLC constant power wide range converter topology and circuit. Background technique [0002] DC-DC converter is an important electrical equipment to realize the conversion and transmission of electrical energy in electrical systems. It is widely used in the fields of power electronics technology, communication power supply, LED lighting power supply and some experimental power supplies. The DC-DC converter can convert the input DC to another fixed or adjustable DC, including DC-DC direct conversion and DC-AC-DC indirect conversion; direct conversion is generally direct conversion without transformer isolation, The indirect conversion adds an AC link in the middle of the converter, and usually uses a transformer to isolate the input and output, so it is also called a DC isolation converter. [0003] In various fields, DC-DC converters are required to have a...

AI Technical Summary

Problems solved by technology

[0004] In order to meet the requirements of wide output voltage range and constant power, the DC-DC converter topology used is basically through electronic switches (relays, semiconductor switching tubes, etc.) and logic control circuits, through different combinations of switches to achieve wide output voltage The range includes changing the series-parallel connection of the primary or secondary windings of multi-winding transformers through switch switching, changing the series-parallel connection of multiple outputs through switch switching, and using the principle of diode voltage doubler rectification to achieve a wide range of output voltages through switch switching; these Although the technology can achieve constant power and wide-range voltage output, it increases additional costs and increases the size of the equipment. For example, by switching the turn ratio of the transformer, the transformer often involves complex windings and is large in size. In addition, the switching is complicated and the switching time It needs to be shut down for a long time to realize the switching, and the overload protection of the parallel section and the series section also need to consider the stress of these devices, switching overvoltage surge suppression, especially when the power demand is greater, this kind of problem is more prominent and seriously affects actual use

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