Input-parallel output-parallel DC-DC converter with MPPT technique for grid connection of multiple distributed generators

Novel input-parallel output-parallel (IPOP) DC-DC converter with maximum power point tracking (MPPT) technique is presented in this paper, which consists of two cascaded stages including buck-boost and isolated boost, so as to achieve high voltage gain and galvanic isolation at proper duty ratio and low leakage energy. Using proposed DC-DC converter, multiple distributed generators (DGs) can be connected to DC grid or subsequent power management unit (PMU) through IPOP method, which is conducive to hot plug in and out of DGs in real applications. Open loop MPPT technique is combined with pulse width modulation (PWM) to control the main switch of the DC-DC converter. Simulation results show that for two identical DG inputs of ~24V, voltage gain reaches 12.6, and total output current is the sum of single unit. For two different DG inputs of ~24V and ~36V, output voltage is boosted by an average factor of 15.3. In both conditions, stable output with small ripple are obtained, proving the suitability of the proposed DC-DC converter and grid connection method in DG applications.