Abstract: In order to solve problems in the prior art, the invention provides a current difference control method for an input-series and output-parallel type DC/DC converter. The total number of system loops is minimized based on a master-slave structure. A master module is provided with only one voltage loop to control the output voltage. The output current of the master module serves as a reference for the output current loop of a slave module. The voltage loop and the output current loop are in a parallel relationship. During designing, the control parameters of the master module and the slave module can be designed respectively and separately, so that the mutual influence therebetween is avoided. The output currents of the two modules are controlled to be equal, while the voltage-sharing effect is realized at the input ends thereof. Since the output currents are controlled, no conventional input grading ring is required. Therefore, the complexity of a telemetry circuit is simplified. The reference currents of the output current loops of all the above modules are provided by the same master module, so that the summation operation of all sampling currents is avoided. The method is simple and easy to realize, and the accurate voltage-and-current sharing effect is realized. When the extension and the redundant backup of the system are required, the system runs in the master-slave mode automatically. Therefore, the failure of the master module and the breakdown of the system are avoided.
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