A dc-dc converter and its control method

Abstract

The present invention relates to a DC-DC converter and a control method thereof. The DC-DC converter includes a control circuit, a BOOST voltage boosting main circuit and a soft switching auxiliary circuit, and the output terminals of the control circuit are connected to the BOOST voltage boosting circuit respectively. The input end of the main circuit is electrically connected to the input end of the soft switching auxiliary circuit, the output end of the BOOST boost main circuit is electrically connected to the input end and the output end of the soft switching auxiliary circuit, and the control circuit is used for Controlling the zero-voltage turn-on and turn-off of the BOOST step-up main circuit, and controlling the zero-current turn-on and turn-off of the soft-switching auxiliary circuit. The technical scheme of the invention reduces the switching loss of the power device, weakens the voltage peak and the current peak, and meanwhile the device occupies a small space.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a DC-DC converter and a control method thereof. Background technique [0002] With the global energy shortage and people's increasing attention to the living environment, fuel cell electric vehicles have attracted widespread attention due to their advantages such as high energy conversion rate, zero pollution and good fuel economy, and are developing at a high speed. [0003] Since the output voltage of the fuel cell varies in a large range, it is difficult to directly supply power to the electric drive system of the electric vehicle. Therefore, a DC-DC converter is required. For example, the electric energy output by the hydrogen fuel cell is converted by the DC-DC converter and delivered to the Power batteries and electric drive systems, etc. At present, the commonly used DC-DC converter is the BOOST boost converter. The existing BOOST boost converter often adopts ha...

AI Technical Summary

Problems solved by technology

At present, the commonly used DC-DC converter is the BOOST boost converter. The existing BOOST boost converter often adopts hard switching technology, which makes the switching loss of the power device large, the efficiency of the whole machine is low, and the voltage spikes during the switching process of the power device And the current peak is high, so that the power device is easy to overvoltage and overcurrent, and the electromagnetic interference is serious. At the same time, the switching frequency of the hard switching technology is not high, usually need to use a larger magnetic device, which will lead to the oversized and heavy machine.

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