Switch-sharing-based multilevel inverters offer great advantages in terms of efficiency improvement and output quality enhancement for low-power photovoltaic (PV) applications. However, the capacitor voltage balancing issue may critically deteriorate the output voltages, and thus could nullify the aforementioned benefits. Hence, this paper proposes a capacitor voltage balancing solution based on a buck-boost converter with performance-based tuning controllers to address the issue. The proposed controllers are designed based on the proportional-integral (PI) configuration equipped with an online tuning mechanism. The main purpose of the online tuning mechanism is to fine tune the proportional gain according to the DC input voltage, based on the measured output current total harmonic distortion (THD) performance of the inverter, while at the same time preventing the controller from reaching a state of saturation. By using the actual measurement of current THD performance, online tuning accuracy can be improved since no ideal condition is assumed, and thus, the associated error can be minimized. Simulation and experimental results reveal that the capacitor voltages can be balanced at high modulation indexes with improved current harmonic performance able to be be acquired at the inverter’s output.

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Free-space optics (FSO) communication is a technology that uses light to transmit data through free space. The most important part in FSO communication is the alignment between transmitter and telescope’s receiver. However, since the transmission medium of FSO is atmosphere, it will give misalignment between the transceivers. Hence, auto tracking system is required to solve the problem between the transmitter and receivers. The 3-RPS parallel manipulator has been designed as an auto tracking system for the alignment between transceivers. First, a prototype of the system is designed in SolidWorks and integrated with LabVIEW software to perform virtual prototyping. Then, the result of virtual prrotyping is discussed.