A PV cell is composed of one or two layers of semiconductor materials like silicon.
The number of PV modules in series and parallel are chosen such that they satisfy the voltage and current requirements of the project.
A PV inverter can be a string inverter or microinverter, and both types synchronize the photovoltaic power to the utility grid power frequency.
Photovoltaic refers to the direct conversion of sunlight into electricity using solar panels
Population growth, urbanization, and industrialization have drastically increased our demands for power. To address this, various electric power generation options have been developed. The trend in power generation to incorporate zero-emissions sources or green energy sources, popularly known as renewable resources, is one of the best options to address power scarcity. The global demand for green energy has led to tremendous market growth of solar photovoltaic power systems. Over the past decade, photovoltaic power system components have seen a depreciation of more than 70% of their initial cost. Governing bodies and other authorities have supported photovoltaic power systems by giving incentives and subsidies.
Circuit design with photovoltaic modules is a hot research topic. Solar photovoltaic power system designs involve several components and developments to offer better performance and increased efficiency. In this article, we will discuss the conventional components present in circuit designs with photovoltaic modules.
Photovoltaic Cells and Types
The utilization of solar energy is one of the solutions for exponentially increasing power demand. Solar power generation is a secure energy supply option for the future. The merits of solar power generation include abundance, non-depletion, zero carbon emissions, and no waste generation. The phenomenon of photovoltaics is the basic principle of solar power generation. Photovoltaics refers to the direct conversion of sunlight into electricity using solar panels. Solar panels or photovoltaic (PV) panels or PV modules are the intermediate systems in solar power generation that enable the production of electricity. Solar panels are formed by arranging solar cells or PV cells.
What Is a PV Cell?
A PV cell is composed of one or two layers of semiconductor materials like silicon. There are different types of solar cell classifications—such as crystalline solar cells and thin-film solar cells—based on their manufacturing processes.
Crystalline solar cells are of two types: monocrystalline solar cells and multi-crystalline solar cells.
Thin-film solar cells can include amorphous silicon, cadmium telluride, and copper indium gallium di-selenite (CIGS).
Perovskite solar cells are currently in high demand in the photovoltaic market.
The Generation of Electricity Using PV Arrays
Irrespective of the solar cell type, multiple PV cells are arranged to form a PV module. Multiple PV modules are arranged together to build a PV array. PV arrays are the most significant part of solar photovoltaic power generation. When light falls on PV arrays, it is converted into a direct current. Each PV cell produces a certain DC voltage and the overall effective voltage and current from the PV array depends on the series-parallel arrangement of the PV cells. The direct current produced by the PV array needs to be converted into alternating current for use in domestic, commercial, and industrial systems. Inverters are utilized for DC to AC conversion.
Solar power generation is not solely based on sun and PV arrays. Circuit design with photovoltaic modules requires several supporting systems like an inverter. In the upcoming section, we will discuss various components in photovoltaic circuit designs.
Circuit Design With Photovoltaic Modules
Major components in photovoltaic power generation systems are:
The circuit design of photovoltaic power generation is impossible without PV modules. PV modules are available in different sizes and varieties. The ones that best suit the space and load of the project should be selected. PV modules are connected in series and parallel to form the PV array. The number of PV modules in series and parallel are chosen such that they satisfy the voltage and current requirements of the project. Additionally, combiner boxes are installed to combine the electric power generated in multiple PV modules into one output circuit.
PV Module Mounting Racks
PV module mounting racks are the mechanical structures that hold PV arrays in certain orientations. The orientation is based on the direction in which the maximum sunlight falls on the PV array. In the northern hemisphere, the PV arrays are oriented in the south direction for maximum solar irradiation. Usually, the orientation is secured using mounting racks placed on the roof or ground. The mounting racks are designed such that they withstand the PV module weight as well as wind loads.
PV Inverters for DC to AC Conversion
Since most of the systems used in residential, commercial, and industrial sectors are wired for AC power, there is a need to convert the DC power generated in PV arrays to AC power. Whether a stand-alone system or a grid-connected system, the inverter converts the DC to AC power. In a grid-connected system, the inverter enables seamless connection to the power grid. The PV inverter can be a string inverter or microinverter, and both types synchronize the photovoltaic power to the utility grid power frequency. Grid-connected PV inverters are capable of preventing islanding during no utility power conditions.
The electrical panel of the photovoltaic system covers safety and protection equipment. The switchgear and protection is an inevitable part of a good photovoltaic electrical panel circuit design. It follows electrical codes, such as NEC 690, and good system design. The main components of electric panels include fuses, circuit breakers, relays, and switches. At times, the electrical panel includes transformers for higher voltage interconnections.
In certain circuit designs with photovoltaic modules, battery banks are incorporated for storing and utilizing photovoltaic power when sun or grid power is not available. Cadence software can help you in designing standalone as well as grid-connected solar power generation systems.