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This paper presents a single-phase differential-type photovoltaic inverter named single inductor dual buck-boost inverter (SIDBBI) based on improved half-cycle PWM (HPWM). Conventional DBBI (CDBBI) is a good option for photovoltaic application due to step-up/down ability for varying inputs. However, inherent high inductor current and corresponding increments of inductor size and device ratings have made it less attractive than other topologies. This paper proposes an HPWM scheme with active clamping switches to reduce inductor voltage swing, highly induced current and component stresses by eliminating output voltages offsets. Under the proposed modulation, component voltage stresses in CDBBI can be reduced by zero offset, and there arises a chance to integrate half-utilized inductors, main switches and complementary diodes of two modules into one set, which is the proposed SIDBBI topology. 500 W prototypes of the conventional/proposed inverters have been built for verifications and comparison. Detailed analysis and experimental results under the proposed HPWM show that the size of SIDBBI can be reduced by 40.4% than CDBBI, maintaining comparable efficiency over 96% and wide input coverage by step-up/down ability. Comparative results address that SIDBBI is competitive in terms of component counts, stresses and losses, compared with various kinds of buck-boost inverter topologies. [ABSTRACT FROM AUTHOR]

In this study, the authors propose a feedback control method for energy storage systems for storing electrical energy and for load levelling. The proposed method uses both source and load power feedback, resulting in a fast response with respect to load levelling. To verify the proposed system, a power conditioning system based on the proposed feedback scheme was implemented and tested, in order to show the effectiveness of the scheme with respect to load levelling and energy harvesting. The system involved 60 of 50 W photovoltaic panels and a 20 Ah lithium polymer battery. An office was selected for testing, which was performed over an entire year. The authors obtained the operating profiles and determined the reduction in the daily total energy usage of the consumer as well as the standard deviation in load levelling. [ABSTRACT FROM AUTHOR]