Diodes or SCRs? It's Either Or
While reading Cory Lamerande’s article on harmonic distortion (March issue), I found a contradiction. The text under Figure 5, on page 74, (reproduced above) states: “Assume the diodes are SCRs, and you have a circuit found in most AC drives.” On page 76, the second paragraph begins: “In most AC drives, the input rectifier uses a diode bridge.” Lemerande can’t have it both ways. Most of today’s PWM