Phase Locked Loop

Any grid connected inverter requires accurate information of the phase angle and frequency of the grid through a Phase Locked Loop (PLL). The tutorial will describe through simulations, every aspect of the implementation of a PLL in software which in hardware would be through a Digital Signal Processor (DSP) or an equivalent embedded processor. The outline of the tutorial is as follows:

  1. The need for a PLL and the basic concept behind a software PLL.
  2. The concept of transformation that forms the basis of a software PLL with a single-phase system.
  3. The closed loop to generate the synchronization.
  4. Transformation applied to a three-phase system.
  5. The effect of unbalance with respect to oscillations in the phase angle and the need for a notch filter.
  6. The design of a notch filter.
  7. The working of a PLL in practical conditions.

This tutorial is accompanied by a number of simulation cases. It is recommended to try out the simulation cases while reading the tutorial.

The report for the tutorial can be found in the link:

Click here for report

The simulation files for the tutorial can be purchased from the link:

All the latest updates in the project are added to the Updates page:

The latest version of the software can be found on the link:

In order to install the software, read the document INSTALL.pdf:

To use the software, check out the user manual:

For further questions, contact me by email at