| Summary: | 碩士 === 崑山科技大學 === 電機工程研究所 === 102 === The input-series output-parallel (ISOP) modular DC-DC converter based on asymmetrical half-bridge converters (AHBC) is studied in this thesis. It consists of three AHBC modules connected in series at the input and in parallel at the output with interleaved operation. The converter is suitable for high input-voltage and high output- current applications. To ensure the proper operation, the input voltage sharing and output current sharing evenly are the key techniques of the ISOP modular converters.
Based on the small-signal equivalent circuit of AHBC converter, the small-signal transfer functions from the duty cycle to the output voltage and the module input voltages of the ISOP-AHBC modular converter are derived. This thesis uses a new two-loop control strategy which has the advantage of decoupling the input voltage sharing regulation (IVSR) and output voltage regulation (OVR). In other words, the control system can be decoupled from three independent single-input and single-output systems. The K-factor method is used to design the controllers such that the goals of input voltage sharing evenly, output current sharing evenly and output voltage regulation are reached.
Finally, the experimental result of the ISOP modular converter is presented. The converter with input voltage 600 V, output voltage 24 V and output power 720 W is implemented. The performance of input voltage sharing regulation, output current sharing regulation and output voltage regulation is conformed under the conditions of input voltage variation and load change.
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