Static and Dynamic Analyses of Integral Pulse-Width Pulse-Frequency Modulator with Small Error-Reset Integrator Logical Circuit

In this study, the static and dynamic analyses of a modified integral pulse-width pulse-frequency (PWPF) modulator with small error-reset integrator (SE-RI) logical circuit are carried out using grid search method. A set of quasi-normalized equations is utilized in order to reduce the number of parameters, that is, the integrator gain and the maximum torque of modulator are merged to other parameters. The output of the modified integral PWPF (IPWPF) modulator is limited to ۵۰ Hertz.The preferred regions of the IPWPF are chosen by the amount of limitation on fuel consumption and thruster firings. These preferred regions are obtained for different dead zone values of SE-RI circuit. The analyses are performed in two methods with different choices of Schmitt-trigger parameters (i.e., hysteresis or threshold ratio). The proposed regions described by simple inequality relations represent the rectangular regions, which does not give the whole preferred region. As an advantage of the study, the preferred regions are presented graphically instead of rectangular regions by inequality relations.

Keywords:

Integral Pulse-Width Pulse Frequency Modulator , On-off thrusters , Spacecraft attitude control