The invention provides an input-series-output-parallel (ISOP)
system having natural
voltage sharing characteristic and a control method thereof. The
system comprises n sub-modules, wherein each sub-module comprises a
Boost converter and an LLC
resonant converter, n is a natural number larger than or equal to 2, in each sub-module, the
Boost converter is a front stage, the LLC
resonant converter isa rear stage, an output of the
Boost converter is used as an input of the LLC
resonant converter, the two
converters are connected by an intermediate
bus capacitor, input ends of the Boost convertersof the n sub-modules are sequentially connected in series, a positive
electrode of an input
voltage source is connected with an input positive end of a first Boost converter, a negative
electrode ofthe input
voltage source is connected with an input negative end of an n(th) Boost converter, and output ends of the LLC resonant
converters of the n sub-modules are connected in parallel and are respectively connected with a positive end and a negative end of an output
resistor. By the
system, no extra measure is needed to be added, input voltage sharing and output
current sharing of the ISOP system can be achieved, and the influence of inconsistent parameter among the modules on a voltage sharing and
current sharing effect is relatively small. The implement method is simple, and the reliability of the system can be greatly improved.