BEE BEE Bachelor of Electrical Engineering Control System Principles Questions and Answers 2

Question 1

What is the primary purpose of a lead compensator in a control system?

Accepted Answer

To improve transient response by adding phase lead

Answer

A lead compensator adds positive phase to the system near the crossover frequency, improving transient response and stability margins.

Question 2

In a Bode plot, what does a slope of -40 dB/decade indicate about the system's transfer function?

Accepted Answer

Two poles at that frequency range

Answer

Each pole contributes -20 dB/decade, so -40 dB/decade indicates two poles are dominating in that frequency range.

Question 3

Which criterion determines the absolute stability of a linear time-invariant system by examining the characteristic equation coefficients?

Accepted Answer

Routh-Hurwitz criterion

Answer

The Routh-Hurwitz criterion uses the coefficients of the characteristic polynomial to determine whether all roots lie in the left-half plane.

Question 4

What does a phase margin of 0 degrees indicate about a feedback control system?

Accepted Answer

The system is on the verge of instability

Answer

A phase margin of 0 degrees means the open-loop phase is exactly -180 degrees at the gain crossover frequency, placing the system at the boundary of instability.

Question 5

In state-space representation, what does the controllability matrix being full rank guarantee?

Accepted Answer

The system state can be driven to any desired state using the input

Answer

Full rank of the controllability matrix ensures that every state is reachable from any initial condition through appropriate input signals.

BEE - Bachelor of Electrical Engineering Practice Test

BEE - Bachelor of Electrical Engineering Practice Test

BEE BEE Bachelor of Electrical Engineering Control System Principles Questions and Answers 2