Abstract
Problem for finding the optimal PWM waveform, namely, the optimal PWM problem, is reduced to that for finding zeros of certain orthogonal polynomials. However, since the optimal PWM problem is rather ill-conditioned, one cannot solve a higher order optimal PWM problem in a double-precision floating-point number. In this note, numerical algorithms for solving optimal PWM problem on multiple-precision arithmetic are considered being based on orthogonal polynomials. Among several methods we experimented, solving a real symmetric tridiagonal matrix eigenvaule problem reduced from the optimal PWM problem is better than others with respect to speed and accuracy.
