With the increased availability of power MOSFET's and insulated gate bipola
r transistors, a new generation of simple choppers for ac inductive loads i
s foreseen. These new power semiconductors ease the use of forced commutati
ons of thyristor snitches to improve the supply power factor, even with hig
hly inductive loads. The ac controllers with thyristor technology can be re
placed by pulsewidth modulation (PWM) ac chopper controllers which have imp
ortant advantages. In this paper, a symmetrical PWM ac chopper designed to
operate with single-phase inductive loads with a reduced number of controll
ed switches is described. The operation as a variable voltage source of thi
s converter is evaluated. This includes the conversion characteristics, har
monic generation, harmonic distortion factor, and input power factor. By di
gital simulation, these characteristics are investigated theoretically, and
to correlate the measurements,vith theory, an experimental setup is presen
ted to confirm the analytical analysis.