Power Converters and AC Electrical Drives with Linear Neural Networks

3

Power Quality

3.1 Nonlinear Loads

3.1.1 Current Source Type of Harmonic Sources (Harmonic Current Sources)

The classic harmonic current source (CS) is the thyristor rectifier with a series inductance, which maintains the load current constant, as shown in Figure 3.1. The switching operation of the diodes makes the source current periodic (three-step square wave) but nonsinusoidal; as a consequence, a distortion on voltage source (VS) occurs due to the voltage drop on its impedance. Since this kind of load imposes the distorted current to the source, it is called harmonic CS. In this case, the load current is not significantly dependent on the AC side, so it can be considered a CS. Figure 3.2 shows the typical time waveform of the ...