Soft switch isolation type boost direct current converter and control method thereof

Abstract

The invention discloses a soft switch isolation type boost direct current converter and a control method thereof and belongs to the field of power electronic converters. The converter is formed by an input source (Uin), a primary side switching circuit (10), an auxiliary side switching circuit (20), an inductor (Lf), a transformer (T), a first output filtering capacitor (Co1), a second output filtering capacitor (Co2) and a load (Ro). The primary side switching circuit (10) is formed by four switching tubes, and the auxiliary side switching circuit (20) is formed by two diodes and two switching tubes. The converter achieves control of output voltage through phase shifting control of the switching tubes in the primary side switching circuit (10) and the auxiliary side switching circuit (20). The converter has the capability of achieving soft switching of all switching tubes in the whole load range, can achieve high-frequency high-efficiency power conversion, can effectively reduce the size of the inductor and the transformer, achieves high-power density, is simple to control, high in reliability and easy to achieve and provides a key technical scheme for isolation type high-efficiency power conversion.

Description

technical field [0001] The invention relates to an isolated soft-switching DC boost converter and a control method thereof, belonging to the technical field of power electronic converters. Background technique [0002] The isolated DC boost converter is suitable for occasions that require electrical isolation of the input and output and the output voltage is higher than the input voltage. This type of converter has a wide range of applications in new energy power generation, industry, civil, aerospace and other fields. [0003] Traditional isolated DC converters, such as forward converters, flyback converters, push-pull converters, half-bridge converters, full-bridge converters, etc., can achieve the expected boost requirements by adjusting the transformation ratio of the transformer . However, simply relying on adjusting the transformation ratio of the transformer to achieve the boost has the following problems: the voltage stress of the switching device is high, especiall...

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Problems solved by technology

However, simply relying on adjusting the transformation ratio of the transformer to achieve the boost has the following problems: the voltage stress of the switching device is high, especially the voltage stress of the rectifier diode on the secondary side of the converter is much higher than the output voltage; the leakage inductance of the transformer increases, causing the switching device Voltage spikes and oscillations, further stressing switching devices, reducing reliability and efficiency

[0004] The step-up full-bridge isolated DC converter (also known as the current source full-bridge isolated DC converter) can achieve a higher isolation boost capability without increasing the transformer ratio. However, when the switch commutates, due to the limitation of the transformer leakage inductance the rate of rise of the current in the transformer, the filter inductance at the input will cause severe voltage spikes

In order to improve this problem, it is necessary to introduce various voltage clamping or sinking circuits, the literature "Anmad Mousavi, Pritam Das, Gerry Moschopoulos.A comparative study of a new ZCS DC-DC full-bridge boost converter with a ZVS active-clamp converter, IEEETransactions on power electronics, vol.27, no.3, March2012, pp.1347-1358."A detailed analysis of the voltage spike problem in the step-up full-bridge isolated DC converter, and a comparative analysis of various voltage The clamping scheme, although it further proposes an improved absorption circuit scheme, these schemes increase the complexity of the circuit to varying degrees, increase the cost of the converter, increase the difficulty of control, reduce the efficiency of the converter and reduce the Reliability

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