Pulsewidth modulated amplifier for DC servo systems

In control sytem design, one of the major problems faceing a designer is the power dissipated in the system. In large systems, which require high, torque and low speed, the power dissipated in linear amplifiers is highly undesirable. One way to solve this problem is by utilizing switching amplifiers or pulsewidth modulated amplifiers. The design of this type of amplifier is implemented in a dc servo system. Furthermore, measurements and other design considerations are taken practically. It is with these types of amplifiers that this research is concerned. The method used to meet the control requirements was to switch the amplifier at a constant frequency and to vary the "on" and "off" phases of the period according to the need.

The controlling capabilities of the system designed were limited to a particular range of frequencies determined by the finite switching time of the power transistors and the bandwidth of the system. The control requirements were well within the limitations of the feedback control system designed.