The DC-DC boost-buck converter for SPV array fed BLDC motor driven water pump has been proposed. The complete system has been designed, modeled and simulated in MATLAB/Simulink environment and implemented on a developed hardware prototype. Utilizing all the properties of both the boost and buck converters and connecting these two converters in an appropriate manner, a new BB converter with the low valued components has been designed and operated in CCM. Working as a non-inverting buck-boost converter, the proposed BB converter has eliminated the drawbacks of the buck, boost and topologies of buck-boost converters used in SPV based applications. The water pumping has been attained even at the minimum solar insolation level and the starting current of the motor has been controlled within the permissible range. Moreover, fundamental frequency switching of the VSI has avoided the high frequency switching losses. The presented simulation and experimental performances of the proposed system at starting, dynamic and steady state have proven its suitability for the SPV array based water pumping