This paper presents a comparative study of discrete proportional integral (PI) and proportional resonant (PR) current control for single-phase uninterruptible power supply (UPS) inverters. There is an increasing requirement for current and voltage-controlled UPS inverters with very low or zero steady-state error, improved transient response and lower total harmonic distortion (THD). The most promising type of current regulator for single-phase inverters is PR control because it can introduce an infinite gain at a selected resonance frequency such as the fundamental frequency to eliminate the steady-state error, which cannot be achieved by well-known proportional integral (PI) control. Note that PI control has limitations in terms of the steady-state magnitude and phase errors. In addition, PI control also has limited harmonic rejection capability, unlike the PR control, also can compensate for low-order harmonics. Imperfections in the current and voltage control scheme results in higher harmonic distortion of the output current and voltage. In this paper, performance of PR control parameters (Kp, Ki, and ωc) and filter parameters (Lf and Cf) are optimally tuned to obtain a very low current THD with reduced output voltage ripple and steady-state error. The analysis, design and implementation of both PI and PR current control in single-phase UPS inverter applications through simulations and experiments are also presented in this paper. The performance of both of these control schemes are analyzed in terms of steady-state response, transient response, and level of current harmonics.

Over the last decade, dc-dc power converters have attracted significant attention due to their increased use in a number of applications from aerospace to renewable energy. The interest in wide bandgap (WBG) power semiconductor devices stems from outstanding features of WBG materials, power device operation at higher temperatures, larger breakdown voltages, and the ability to sustain larger switching transients than silicon (Si) devices. As a result, recent progress and development of converter topologies, based on WBG power devices, are well-established for power conversion applications in which classical Si-based power devices show limited operation. Currently, Si carbide (SiC) and gallium nitride (GaN) are the most promising semiconductor materials that are being considered for the new generation of power devices. The use of new power semiconductor devices, such as GaN high electron mobility transistors (GaN HEMTs), leads to minimization of switching losses, allowing high switching frequencies (from kHz to MHz) for realizing compact power converters. Finally, design recommendations and future research trends are also presented.

Tilt angle of a PV module is one of the most significant parameters for receiving maximum solar irradiation falling on the PV systems. This research article investigates the numerical aspects of selecting the optimal tilt angle for the PV modules used in Bangladesh and makes recommendations on how the collected power output of the module can be increased by altering the tilt angle. The results show that the optimum tilt angle of Cox's Bazzar Chittagong, Dhaka, Jessore, Ishurdi, Bogra, Sylhet and Rangpur is 26°, 25°, 30°, 25°, 27°, 27°, 28° and 29°, respectively. The annual energy production of Cox's Bazar and Sylhet has shown the highest and the lowest energy production, the month was March and July, respectively. The characteristics curves obtained by the simulation with the data provided by using simulated software SAM (System Advisor Model). Finally, the article measures the optimum tilt for PV applications in Bangladesh on Monthly and yearly bases.

This paper presents the analysis of current harmonics compensation using the proportional-resonant controller for single-phase stand-alone photovoltaic inverter applications. The effect of frequency variation in the reference signal to the controller performance was also analyzed. The controller parameters (K_p , K_i , and ω_c ) and the inductor-capacitor (LC)-filter parameters are optimally selected to obtain a very low current total harmonic distortion . The control algorithm was implemented using a low-cost digital signal processor (DSP) TMS320F28335 eZdsp development board. Both simulation and experimental results validate the performance and the effectiveness of the control technique used.