Three Phase Voltage Source Inverter Operating in Square Wave Mode

A three phase voltage source inverter is a type of inverter that converts DC voltage into AC voltage. It is commonly used in industrial applications to control the speed of AC motors. In square wave mode, the inverter produces a square wave output voltage.

Harmonics in Output Line Voltage

When a square wave voltage is applied to a load, it contains harmonics, which are multiples of the fundamental frequency. The harmonic content of the output line voltage depends on the waveform of the input voltage and the load impedance.

In a three phase voltage source inverter operating in square wave mode, the output line voltage is free from the 3rd harmonic. This means that the harmonic content of the output voltage does not contain the 3rd harmonic component.

Importance of 3rd Harmonic

The 3rd harmonic is particularly important because it causes a number of problems in power systems, including:

- Increased losses in transformers and other equipment
- Overheating of equipment due to increased losses
- Distortion of voltage and current waveforms
- Interference with communication systems

Therefore, the absence of the 3rd harmonic in the output line voltage of a three phase voltage source inverter operating in square wave mode is desirable and beneficial for power system operation.

Conclusion

In conclusion, a three phase voltage source inverter operating in square wave mode produces an output line voltage that is free from the 3rd harmonic. This is beneficial for power system operation, as the 3rd harmonic causes a number of problems in power systems.