Solar Inverters: How do they work and what type is right you?
Grid-tied solar inverters are not as sexy as solar panels, but they are arguably the most important part of a solar electric system. Inverters perform two primary functions:
1) Convert solar DC power to AC power, which we use in our buildings
2) Are a safety mechanism that shuts off system when the grid goes down.
Convert Solar DC Power to AC Power
DC power coming from a solar panel is converted AC power, which is the type of power delivered by the utility and is used to power appliances, lighting, etc. In many cases, the inverter connects to the electric panel via a breaker within the panel.
This allows solar power to simply work as another source of energy in buildings and allows energy to be back-feed to the utility. When this happens, the meter spins backwards, effectively storing excess energy in the daytime for later use.
Grid-tied solar inverters will automatically shut off when the utility power goes out. This provides an important safety mechanism that prevents power from feeding back to the lines.
Central inverters have been the standard for many years in the solar industry. Energy is harvested from a series of solar panels called a string. These strings produce DC voltage that is fed down to the inverter where it is converted to AC power. The inverter is typically located near the electric panel to allow us to connect to the electric service. The straightforward design of a solar system with a central inverter continues to make central inverters a good choice for many systems today.
Micro-inverters perform the same primary functions as a central inverter. However, they perform these functions for each solar panel. They are typically mounted on the solar racking or directly to the solar panel itself. They are a good choice if the solar array is dispersed over differently oriented roof sections or if a portion of the array is shaded during parts of the day. They also allow monitoring of each solar panel’s production. While more expensive than a central inverter, they are also a good choice for many customers.