Non-symmetrical PWM control type ISOP full-bridge direct-current converter and control method thereof

Abstract

The present invention discloses a non-symmetrical PWM control type ISOP full-bridge direct-current converter and a control method thereof. The input side of each module of a converter comprises an input capacitor, an inverter bridge and a transformer primary side. The output side of each module of the converter comprises a transformer secondary side, a full-bridge rectifier circuit and an LC filter circuit. The positive electrode of an input direct-current power supply is in series connection with an input inductor and then is connected to the first bridge arm middle point of the inverter bridge of the input side of the first module. The negative electrode of the input direct-current power supply is connected with the negative end of the input capacitor of the last module. The connection mode of two adjacent modules is as follows: the negative end of the input capacitor of a former module is connected with the first bridge arm middle point of the inverter bridge of a latter module. Based on the above structure, the capacitive short circuit problem of the input power supply during the short-circuited stage can be effectively avoided. The converter is modulated in the non-symmetrical PWM manner, so that the voltage of the input capacitor is reduced. The capacitance value and the size of the input capacitor are reduced. The modules are driven in the staggered manner, so that the input and output current / voltage ripples are effectively reduced, and the requirements of a filter are lowered.

Description

technical field [0001] The invention relates to a power electronic device and a control method, in particular to an ISOP full-bridge DC converter controlled by an asymmetrical PWM and a control method thereof. Background technique [0002] As an important branch of power electronics integration technology, the multi-converter series-parallel system has been a research hotspot in recent years. [0003] Since the multi-module series-parallel system has the advantages of reducing development difficulty, facilitating expansion, realizing system redundancy and high reliability, it is widely used in systems such as distributed power generation, power electronic transformers and uninterruptible power supplies. For multi-converter series-parallel systems, systems with different series-parallel combinations are used in different situations. Taking the ISOP system as an example, it is suitable for high voltage input and high current output occasions. For example, high-power DC switc...

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Problems solved by technology

[0004] The input terminal of the traditional ISOP full-bridge DC converter system adopts the method of connecting each module directly in series with capacitors to realize the series connection of the input terminal, but this method will cause all the voltage dividing capacitors to be connected together when the input power supply is short-circuited. Short circuit will burn out components

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