Solar inverters are an important part of solar energy generation systems that transform direct current (DC) power from solar panels into alternating current (AC) for consumption in homes or industry. 

With the continuous development of solar energy technology, inverters play a more and more crucial role in energy conversion. Their principles of operation, types, benefits, and maintenance need to be understood in order to choose solar inverters correctly.

What is a solar inverter?

Solar inverters are the principal devices that link solar panels with electrical loads such as domestic appliances and industrial equipment. Its key function is to convert the direct current generated by solar panels into alternating current used in household or commercial power grids.

The role of inverters in solar energy systems

The current generated by solar panels is direct current, while most power systems require alternating current. Therefore, inverters are a necessary component for achieving energy conversion. Without an inverter, the electricity generated by solar panels cannot be directly supplied to household appliances or returned to the grid.

Working principle of solar inverter

Solar inverters are the core equipment of photovoltaic power generation systems, whose core function is to convert the direct current (DC) generated by photovoltaic modules into alternating current (AC) that meets the requirements of the power grid or load.

1. DC input and preprocessing
Photovoltaic modules supply unstable direct current under illumination and have current and voltage sensitive to light intensity and temperature. DC power initially passes through the filtering circuit of the inverter (e.g., inductors, capacitors, etc.) to remove high-frequency noise and voltage fluctuations, which gives stability to the input current. The nature of this stage is to avoid the following circuits from transient voltage spikes.

2. The core process of inverse conversion
The core of an inverter is the inverter circuit, which converts DC to AC through fast switching of semiconductor power devices such as IGBT and MOSFET. The specific process is as follows:

• High frequency switch control:
  Power semiconductor devices switch at a frequency of thousands to tens of thousands of times per second, and use pulse width modulation technology to cut DC electricity into pulse sequences.
• Waveform shaping:
  The initial square wave needs to be smoothed through an LC filtering circuit (a combination of inductance and capacitance) to remove high-frequency harmonics, and finally output a sine wave AC power that meets the grid standards

3. Maximum Power Point Tracking (MPPT)
MPPT technology is the inverters’ fundamental algorithm, used to dynamically determine the operation point of photovoltaic modules in a way that delivers maximum power under any circumstance.

For example, if light is reduced or parts get obstructed, MPPT adjusts voltage-to-current ratio (e.g., perturbation observation method or incremental conductance method) to keep the system at the best state of efficiency always