Input-voltage balancing of series-connected converters

Wireless Input-Voltage-Sharing Control Strategy for Input-Series Output-Parallel (ISOP) System Based on Positive Output-Voltage Gradient Method

“…Due to small mismatches in the controller parameters among the three prototypes, such as reference voltages, voltage sensors, and operational amplifiers, the measured maximum input-voltage difference among the three modules is 4 Vdc. It should be noted that even though the control strategies proposed in [9]- [20] are employed for ISOP systems, the input-voltage differences among the constituent modules still exist due to the controller parameter mismatches; however, the detailed precise measured results like those in Fig. 9 are not listed in these papers.…”

“…In [20], the controllers are also distributed into individual module, and one module is controlled to regulate the output voltage, whereas the other modules connected through a sharing bus are controlled to regulate their own input voltages. The modularization architecture realizes the modularity design of the ISOP system and increases system reliability and expansibility.…”

“…In order to ensure the proper operation of ISOP systems, the basic objective is to ensure input-voltage sharing (IVS) and output-current sharing (OCS) among the constituent modules. Control strategies to achieve IVS and OCS for the ISOP system have been studied extensively [1]- [20], and generally speaking, these control strategies can be classified into two categories, one is the natural voltage/current sharing method in which IVS and OCS are achieved without special control approach, and the other is the method with special IVS control approach. Common-duty-cycle control is usually employed for the natural voltage/current sharing method [2]- [7], which relies on the inherent self-correcting characteristic of the ISOP system when the duty cycles of all the constituent modules are the same.…”