Power Electronics

Multi-pulse rectifier

1.4.3 Multi-pulse rectifier.

The other already power electronics techniques is use of multi-pulse rectifiers. Although easy to implement, possess several disadvantages such as: bulky and heavy transformer, increased voltage drop, and increased harmonic currents at non-symmetrical load or line voltages.

Mixing single and three phase diode rectifier

1.4.2 Mixing single and three phase diode rectifier

The other technique, based on mixing single and three-phase non-linear loads, gives a reduced THD because the 5th and 7th harmonic current of a single-phase diode rectifier often are in counter-phase with the 5th and 7th harmonic current of a three-phase diode rectifier .

 

Traditional harmonic reduction technique

The traditional method of current harmonic reduction involves passive filters LC, parallel-connected to the grid. Filters are usually constructed as series-connected legs of capacitors and chokes [the number of legs depends on number of filtered harmonics (5th, 7th, 11th, 13th) ].