Photovoltaic inverters (PV inverters or solar inverters) are inverters that convert the variable DC voltage generated by photovoltaic (PV) solar panels into alternating current (AC) at the mains frequency, which can be fed back into commercial transmission systems or used in off-grid grids. Photovoltaic inverter is one of the important system balances (BOS) in photovoltaic array systems, which can be used with general AC power supply equipment. Solar inverters have special features for PV arrays, such as maximum power point tracking and islanding protection.

Solar inverters can be divided into the following three categories: 1. Stand-alone inverters: used in independent systems, the photovoltaic array charges the battery, and the inverter uses the DC voltage of the battery as the energy source. Many stand-alone inverters also incorporate a battery charger that can be used to charge the battery with AC power. In general, these inverters do not come into contact with the power grid, so there is no need for islanding protection. 2. Grid-tied inverters: The output voltage of the inverter can be sent back to the commercial AC power supply, so the output sine wave needs to be the same as the phase, frequency and voltage of the power supply. The grid-tied inverter will have a safety design and will automatically shut down the output if it is not connected to the power supply. If the grid power supply is lost, the grid-connected inverter does not have the function to reserve power supply. 3. Battery backup inverters are a special type of inverter, which uses the battery as its power source, and cooperates with the battery charger to charge the battery, if there is too much power, it will be recharged to the AC power terminal. This kind of inverter can provide AC power to the specified load when the grid power supply is lost, so it needs to have islanding protection function.

Maximum Power Point Tracking BroadcastEdit Main Article: Maximum Power Point Tracking PV inverters use Maximum Power Point Tracking (MPPT) technology to extract the maximum possible power from solar panels. There is a complex relationship between solar irradiance, temperature, and total resistance of solar cells, so the output efficiency will vary nonlinearly, called the current-voltage curve (I-V curve). The purpose of maximum power point tracking is to generate a load resistance (of the solar module) for the output of the solar module in each environment to obtain the maximum power. The fill factor (FF) of a solar cell together with its open-circuit voltage (Voc) and short-circuit current (Isc) determines the maximum power of the solar cell. The form factor is defined as the ratio of the maximum power of a solar cell divided by the product of Voc and Isc. There are three different algorithms for maximum power point tracking: perturb-and-observe, incremental conductance, and constant voltage, the first two are often referred to as "hill climbing", which follow the voltage-to-power curve, increasing the voltage if it falls to the left of the maximum power point, and decreasing the voltage if it falls to the right of the maximum power point.

Micro PV Inverter Broadcast EditorMicro PV inverter is a PV inverter that only works with a single solar module, converting the DC power of the solar module into AC power. Its design allows multiple micro PV inverters to be operated independently in parallel in a modular manner. The advantages of micro PV inverters include the ability to optimize the power of a single solar module, the ability of each module to operate independently, i.e. ready-to-install method, improved installation method and fire safety, minimal cost of system design, and minimal inventory. A 2011 study by Appalachian State University in the United States pointed out that when using the same solar panels, individual inverters will produce 20% more electricity than a series device with only one inverter, and 27% more power when shielded.

Grid-connected inverter Grid-connected inverter Solar grid-connected inverter is to feed electric energy back to the grid, if the grid is out of power, it is necessary to quickly cut off the power supply to the grid, which is the requirement of the National Electrical Code (NEC) to ensure that when the power is off, the grid-connected inverter will also be turned off to avoid injury to the maintenance of the grid. There are many different technologies for grid-tied inverters on the market today, including the use of newer high-frequency transformers, traditional power frequency transformers, or transformerless architectures. Instead of directly supplying 120 V or 240 V AC power, a high-frequency transformer has a computer-controlled, multi-step process that converts the power supply to high-frequency alternating current, then to direct current, and finally to the voltage and frequency required by the power supply. In the past, there were some doubts about systems that do not have a transformer and have to supply power to the grid, mainly because there is no galvanic isolation between the DC circuit and the AC circuit, and if the DC terminal fails, there will be a large current flowing to the AC terminal. However, since 2005, the National Electrical Code of the National Fire Protection Association (NFPA) allows transformerless inverters. VDE 0126-1-1 and IEC 6210 also allow and define the safety mechanisms required for such systems. First, there needs to be residual current or ground circuitry to detect abnormal short circuits, and insulation tests are also performed to confirm the separation between DC and AC circuits. Many solar inverters are designed to be connected to the grid, and the inverter will not function without grid detection. This type of inverter also has special circuitry, which precisely matches the magnitude, frequency and phase of the output voltage with the power supply.

Solar charge controllers, charge controllers can be used with solar panels as well as devices that use direct current. The charge controller can provide a stable DC power output and store excess energy in the battery, and monitor the battery level to avoid overcharging or over-discharging. Some of the more expensive modules can also support MPPT. The inverter can be connected to the output of the solar charge controller, and the inverter can then push the AC load.

Solar pump inverter, solar pump inverter can convert the direct current generated by the solar module into alternating current to drive the submersible pump, without the need for batteries or other energy storage equipment. With MPPT (Maximum Power Point Tracking), the solar pump inverter can adjust the output frequency to control the speed of the pump and avoid damage to the motor driving the pump. Solar pump inverters generally have several interfaces, which can allow the solar module array to provide DC current, there will be an interface to output AC voltage, and there may also be an interface to the input of the water level sensor.