Niroo Research Institute

The need for sinusoidal voltage waveforms with adjustable amplitude and frequency is essential in many applications. Power electronics converter-based supplies with pulse-width modulation (PWM) introduce high-order harmonics at their output and the use of filters is mandatory to remove the harmonic distortion. However, output filters are undesired in some specific applications such as B-H meter of magnetic devices because they act as the inverter output load together with the actual load affecting the measurement results. This paper explains the principles of operation and design considerations of a controlled AC power supply with nearly sinusoidal output. The proposed AC power supply consists of switching-mode DC-DC converters connected at the DC links of asymmetric cascaded H-bridges (ACHB). The proposed AC power supply offers a nearly sinusoidal output even at high-current low-voltage outputs. A modular compact 63-level supply is designed for the special case of the B-H meter and the simulation results are presented.

This chapter critically engages with the imperative research topic of enhancing social justice in electrical energy distribution by proposing practical solutions within distribution companies. It underscores the pivotal role of justice in decision-making processes within the electricity industry, with a specific emphasis on its impacts on customers. A controllability index is proposed to evaluate the performance of the distribution companies in load management. Analyzing the controllability index variations reveals that while budget increments contribute to enhance the controllability index, there exists a threshold beyond which unlimited budget allocations fail to yield further improvements, owing to geographical and operational constraints. The installation of automation switches emerges as a pivotal factor in elevating the controllability index, prompting the exploration of budget allocation as a multi-criteria decision-making challenge across various distribution companies. Influential criteria, such as the number and length of medium-voltage feeders, weather conditions, and the volume of sensitive loads, play crucial roles in this problem. Ultimately, the findings underscore the indispensability of infusing principles of justice into decision-making processes, ensuring a socially equitable distribution of electricity that integrates technical, economic, and environmental considerations.

Implementing appropriate operating rule curves for water resources systems and hydroclimatic conditions significantly reduce damages floods and droughts damages in the downstream area. This paper uses simulation-optimization approach to establish a multi-purpose reservoir's rule curve. The hedging method is utilized for drought, and the multi-stage flood routing method is used for floods. The melody search algorithm is employed as the optimization algorithm. The Karkhe Reservoir is a case study, facing irregular water distribution and hydrological challenges from extensive domestic and agricultural water usage, varying cultivation patterns, and flood susceptibility. The region grows two types of crops - autumn and summer crops. Autumn cultivation is fundamental and strategic, but water use for summer or water-based crops reduces water resources for it. Meeting water demands from September to November is another challenge due to the overlapping water needs of summer and autumn crops. Significant changes in the upstream and downstream areas, including alterations in the shape and water resource utilization of the catchment area, as well as changes in the rivers' morphological condition and water carrying capacity, make it a constant challenge to determine the optimal water level for the reservoir. The results demonstrate the satisfactory performance of the optimized rule curve.