Solar Energy Harvesting: Power Electronics Interfaces and Control

Abstract

Among renewable energy sources such as biomass, tidal, minihydro, microturbines, and wind, solar energy is one of the most promising sustainable energy resources. Solar energy is converted to electrical energy in photovoltaic (PV) cells through a process called photovoltaic effect. The output voltage polarity of the PV cell is direct current (DC) whose magnitude depends on the connection type of PV cells/modules, while the output current or power mainly varies with solar irradiance. One of the primary tasks in PV systems is to convert the output DC voltage of PV modules to alternate current (AC) to energize general‐purpose AC loads and utility connection. In addition, an interface, which regulates and adjusts the output voltage of the PV, is required because the output voltage of the PV system varies with various factors such as irradiation and temperature. Meanwhile, the power extracted from the PV system must be optimized based on the weather conditions to get the highest efficiency. A PV system is a combination of several components such as PV panels, energy storage system (ESS), and power conditioning units (PCUs). In PV systems, PCU is composed of power electronic converters along with special controls/algorithms, and it is responsible for various tasks including ESS charging, maximum power point tracking (MPPT), and DC–AC conversion. This article aims to describe a complete PV system architecture and design by following design steps: PV cell/module/array modeling, MPPT algorithms and implementation, design and control of DC/DC power electronic converters responsible for MPPT operation, and DC/AC inverter to supply general‐purpose AC loads. In addition to the provided basic concepts, an example of a complete stand‐alone PV system design including the system sizing has been presented. The designed system has been simulated, and detailed results are provided.

Advances and critical aspects in the life-cycle assessment of battery electric cars

“…For example, the on-board electric infrastructure of BEVs is facing fast efficiency improvements: first-generation on-board-chargers were converting up to 40% of electricity into heat losses, 45 while next-generation BEV inverters, chargers, and further electronic parts will be based on wide-bandgap semiconductors offering up to 98% energy efficiency. 86,87 This is going to considerably improve the use-phase carbon footprint of BEVs in view of the 14% charging losses considered so far. 44 Inductive charging, which is believed to be the future of charging BEVs, is presently disadvantaged with having an efficiency of 75%-80% only.…”