Design of a robust PWM power amplifier using approximate two-degree-of-freedom integral-type control

A method is proposed for designing a robust controller for PWM power amplifiers, which are widely used as amplifiers and power supplies. The main technical requirements imposed on PWM power amplifiers are linearity in a wide frequency range and a well-damped fast dynamic response in the presence of extensive load and DC power supply variations. Therefore, in order to satisfy the design specifications, namely, linearity in a wide frequency range and no overshoots during transients, an approximate two-degree-of-freedom integral control structure is proposed and a design procedure for the robust controller is discussed. It is shown by some simulations and experiments that the designed controller shows especially good dynamic performance and effective disturbance rejection in the presence of external disturbances, that is, load and power-supply variations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 68–77, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10102