Grid-connected solar photovoltaic (PV) systems, otherwise called utility-interactive PV systems, convert solar energy into AC power.
Stand-alone or off-grid PV systems can be either DC power systems or AC power systems. In both systems, the PV system is independent of the utility grid.
Solar PV systems are integrated with other power sources, such as diesel generators or renewable sources like wind, to implement the hybrid PV system.
A new, prevailing marketing trend is to showcase a product as an “environmental-friendly solution” or relate it to a reduced carbon footprint. While this technique might be questionable for some products, marketers won’t have any trouble spinning solar photovoltaic systems as environmental-friendly solutions—they truly are.
A solar photovoltaic system is a renewable energy technology that has the complete setup required to harness solar energy as electricity. These systems can be on-grid systems, where the solar energy is converted into AC power to integrate into the grid, or they can be standalone or off-grid AC or DC power systems. Let’s take a look at three different types of solar photovoltaic systems.
1) Grid-Connected Solar Photovoltaic Systems
A grid-connected solar photovoltaic (PV) system, otherwise called a utility-interactive PV system, converts solar energy into AC power. The solar irradiation falling on the solar panels generates photovoltaic energy, which is DC in nature. Using a DC-DC converter, the total photovoltaic DC voltage from the solar panels is raised to a higher DC level.
A DC-DC converter is not an essential part of a grid-connected solar PV system, but it can control the variations in the photovoltaic system and regulate DC voltage. The inverter in a PV system converts the DC voltage (either the DC voltage from the solar panels or the DC-DC converter output voltage) into AC voltage. As this AC voltage is integrated into the grid, the inverter converts the photovoltaic energy into AC power with a frequency that matches the utility grid. The voltage and power quality requirements of the grid are satisfied by the inverter AC output.
Usually, a metering system is installed along with the solar PV system. In residences, when the PV system power is capable of supplying the complete load, utility grid power is not consumed. When PV power is scarce, the remaining power is consumed from the grid. If the PV power generated is in excess, it is supplied to the grid. The solar PV system supplies power only when the grid is energized.
2) Stand-Alone or Off-Grid PV Systems
A stand-alone or off-grid PV system can be a DC power system or an AC power system. In both systems, the PV system is independent of the utility grid. If DC loads are connected to the solar PV system, then the solar panels can supply the DC voltage or a DC-DC converter can be used to convert the photovoltaic energy to higher DC levels. The DC-DC converter boosts the PV voltage to a value that is suitable for the DC loads. Incorporating the DC-DC converter can reduce the number of solar panels in the PV system.
When the loads connected are AC-powered devices, the off-grid PV system utilizes inverters for the conversion of PV voltage to AC voltage. In between DC-DC converters can also be incorporated to reduce the number of solar panels. A DC-DC converter can also be helpful in stand-alone PV systems when storing the PV voltage in batteries.
3) Hybrid Solar PV Systems
A solar PV system is integrated with other power sources, such as diesel generators or renewable sources like wind, to implement a hybrid PV system. Depending on the type of sources incorporated with the solar PV panels, different converters are used in these systems to convert energy into either DC voltage or AC voltage.
In all PV systems, including hybrid systems, a maximum power point tracker (MPPT) is used so that the maximum power is harnessed from the PV arrays. It is not a must-have component in solar PV systems, however, MPPT can help increase the efficiency of the whole system.
Solar photovoltaic systems are the most promising solution to the energy crisis that we are facing globally. Cadence’s software can help in the design and simulation of any type of solar PV system.