Positive Feed-Forward Control Scheme for Distributed Power Conversion System With Multiple Voltage Sources

This paper presents the positive feed-forward control (PFFC) scheme associated with the average current-mode control (ACMC) scheme for the distributed power conversion system with the multiple voltage sources of different power ratings to protect individual voltage sources from the chain reaction of the undervoltage lockout in order not to cause system voltage collapse. The ACMC scheme has the inherent function of the negative feed-forward control (NFFC) to increase the input current of the converter by increasing the control duty cycle of the converter while the source voltage decreases. However, the undervoltage lockout protection of the employed source or converter can be activated if the source voltage drops below the set threshold value. Therefore, the PFFC+ACMC scheme is proposed to reduce the control duty cycle of the employed converter once the source voltage is less than the set threshold value to avoid system voltage collapse. The input current of the individual converter module is regulated by the proposed PFFC+ACMC mechanism in correspondence with the level of the sensed input terminal voltage. Finally, the prototype circuit of a simple interleaved buck-type converter system is built to validate the proposed PFFC+ACMC function.