Dual-bridge DC-DC converter and its control method

Abstract

The invention discloses a DC-DC converter circuit and a relevant control method; wherein, the converter comprises two DC-AC inverters; each can create symmetrical and isolated square waves or other similar AC output voltage. Through the movement of the phase of one of the DC-AC inverters, the overlapping part of the corresponding voltage of a DC output filtration circuit, which is the two DC-AC inverters can be applied to, will be changed accordingly, so as to reach the target of regulating the output voltage. A double half-bridge and double full-bridge DC-DC converters are two typical types of the converters. During normal running process, the bridge-type inverter is always running in a 50 percent of duty cycle, so as to fulfill Zero Voltage Switching (ZVS) in broad loads. Meanwhile, the invention can also eliminate circulation current, so as to improve the efficiency of power conversion. As for the adjustment and startup of low output voltage, the circuit can work in a Pulse Width Modulation (PWM) status.

Description

technical field [0001] The present invention relates to a DC-DC converter (DC-DC Converter), which has two power transformers, is controlled by PWM and phase shifting, and has the characteristics of wide-load ZVS and zero circulation current. More specifically, dual half-bridge and dual full-bridge DC-DC converters. Background technique [0002] In the field of power conversion, high-frequency switching technology is usually used to convert direct current from one voltage level to another isolated voltage level. The use of switching technology greatly reduces the volume of the converter and improves the conversion efficiency. While the industry is enjoying this switching technology, it is facing new challenges, including further improving conversion efficiency, reducing volume and reducing electromagnetic interference (EMI) caused by switching voltage and current. For these challenges, many efforts have focused on the following four areas: [0003] 1. Wide-load zero-volta...

AI Technical Summary

Problems solved by technology

As a result, large load changes can easily cause bias and saturation of the main transformer

Therefore, the asymmetrical half-bridge cannot be used in high-power circuits; when designing, its zero-crossing frequency is relatively lower than that of conventional bridge circuits.

[0013] Although these attempts reduce power consumption and component electrical stress to varying degrees, none of them can overcome the above four problems simultaneously on one circuit.

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