Active Power Filters for 2nd-50th Harmonic Mitigation in Photovoltaic Power Stations

During grid-connected power generation, photovoltaic power stations often generate severe 2nd to 50th harmonic pollution due to the use of inverter technology, leading to power quality issues. As a result, APF (Active Power Filters) have become the preferred equipment for many photovoltaic power stations.

1. Harmonic Issues in Photovoltaic Power Stations
The daily operation of photovoltaic power stations relies heavily on photovoltaic inverters. However, the extensive use of these inverters generates 2nd to 50th harmonics. These harmonics not only pollute the grid and affect power quality but can also cause equipment overheating, malfunctions, and even damage.

2. Working Principle of Active Power Filters
APF Active Power Filters use high-frequency switching circuits to generate currents with the same frequency but opposite phase as the harmonics, thereby eliminating harmonic components. They can specifically target harmonics at certain frequencies (such as the 2nd, 5th, and 7th) generated in photovoltaic power stations while simultaneously addressing higher-order harmonics, such as the 11th, 13th, and 17th. This is crucial for the grid-connected operation of photovoltaic power stations.

3. Application Effects of Active Power Filters in Photovoltaic Power Stations

3.1 Reduction of Harmonic Currents
After installing active power filters, harmonic currents in the grid are significantly reduced, particularly the 2nd to 50th harmonic components, which are effectively suppressed. This not only resolves the harmonic pollution issue in photovoltaic power stations but also enhances grid stability.

3.2 Reduction of Grid Voltage Fluctuations
With the mitigation of harmonic pollution, voltage fluctuations in the grid are effectively controlled, equipment failure rates are reduced, and the working environment for power equipment is improved.

3.3 Improvement of Power Factor
Active power filters can also compensate for reactive power, improving the power factor of photovoltaic power stations. This reduces the burden of reactive power on the grid and further enhances grid operational efficiency.