In this paper, the steady state operations of the
squarewave inverter circuit with a series R-L load are
discussed. The circuit consists of transistors and
feedback diodes. The basic equation is derived from its
equivalent circuit. Solving the basic equation with
steady state conditions, the instaneous value of the
load current i is derived. The period t(2) for which the
current flows from the supply to the load and the
period t(l) for which the current feedbacks through diodes
from the load to the supply are calculated from (i), and
the ratio of t(l) to t(2) is illustrated using power factor
of fundamental wave, pf, as a variable. The ratios of
transistor mean current I(tr), diode mean current I(D),
supply mean current I(s) to the load current I are illustrated using pf as a variable, too. In result, each current ratios to I is shown in simple expressione. The load current can be calculated simply using the coefficient reading off the figure. In addition, it becomes clear from the figure that the load current is scarcely influenced by the harmonic voltage in less than 0.8 of pf. The ratio t(2)/(t(1)+t(2)) calculated in squarewave voltage, shows the limit of pulse width control whose out put voltage is the squarewave
