Control Techniques for Electric Drives

Root Locus Plot

Root Locus Plot: In the electrical drives employing closed loop control techniques, it is often necessary to investigate the effects of changing the parameters of the system on its stability. The drive motor used itself has several parameters and time constants which affect the stability of the motor itself. The controls used also introduce some …

Root Locus Plot Read More »

Relative Stability from the Nyquist Plot

Relative Stability from the Nyquist Plot: Relative Stability from the Nyquist Plot – The considerations discussed above provide information about the absolute stability of the system, i.e., whether the system is stable or not. An equally important system behaviour to be considered is the relative stability. The relative stability is indicative of how various poles …

Relative Stability from the Nyquist Plot Read More »

Nyquist Criterion

Nyquist Criterion: Nyquist Criterion – This stability criterion enables one to establish the stability of a system using a graphical procedure in the frequency domain. Here also there is no necessity for the evaluation of the roots of the characteristic equation. The stability of a closed loop system is revealed by subjecting the open loop …

Nyquist Criterion Read More »

Correlation Between Frequency and Transient Response

Correlation Between Frequency and Transient Response: As has been stated, the use of frequency response for the design of control systems requires a Correlation Between Frequency and Transient Response. Time response specifications are available for the performance of a system. These must be translated to frequency response. There must be frequency domain specifications also, corresponding …

Correlation Between Frequency and Transient Response Read More »