Solving nonlinear equations for selective harmonic eliminated PWM using predicted initial values

The authors report novel methods for determining switching angles for selective-harmonics-eliminated pulse-width modulation (SHE PWM) inverters. Such switching angles are defined by a set of nonlinear equations, and to solve these equations a predicting algorithm is used to calculate initial values which are first-order approximations of the exact solutions. With these predicted initial values, the Newton algorithm can be used to find the solutions within usually only one or two iterations. The authors also suggest another approach for solving the SHE PWM problem: an ordinary differential equations approach. The advantages of this approach are discussed, and its applications are demonstrated by some examples.<>