PPT Controllers & Compensators - Control Systems - Electrical Engineering (EE)

 Page 1


COMPENSATORS
? Types of compensators
? S-Plane representation of compensator
? Comparision of Compensators
Page 2


COMPENSATORS
? Types of compensators
? S-Plane representation of compensator
? Comparision of Compensators
Compensator
• The control system are designed to perform specific tasks. The requirement of a
control system are usually specified as performance specifications.
• The specifications related to accuracy, relative stability and speed of the response.
The design problem may be stated as follows:
• When a set of specifications are given for a system, then a
suitable compensator should be designed so that the overall system will meet the
given specification.
• The compensation schemes used for feedback control system is either series 
compensation or parallel feedback compensation.
Page 3


COMPENSATORS
? Types of compensators
? S-Plane representation of compensator
? Comparision of Compensators
Compensator
• The control system are designed to perform specific tasks. The requirement of a
control system are usually specified as performance specifications.
• The specifications related to accuracy, relative stability and speed of the response.
The design problem may be stated as follows:
• When a set of specifications are given for a system, then a
suitable compensator should be designed so that the overall system will meet the
given specification.
• The compensation schemes used for feedback control system is either series 
compensation or parallel feedback compensation.
The choice between series and parallel compensation
depends on:
1. Nature of signals in the system
2. Power levels at various points
3. Components available
4. D e s ig n e r ’ s experience
5. Economic considerations and so on.
The different types of electrical or electronics compensators used are
? Lag compensator
? Lead compensator
? Lag-lead compensator
Page 4


COMPENSATORS
? Types of compensators
? S-Plane representation of compensator
? Comparision of Compensators
Compensator
• The control system are designed to perform specific tasks. The requirement of a
control system are usually specified as performance specifications.
• The specifications related to accuracy, relative stability and speed of the response.
The design problem may be stated as follows:
• When a set of specifications are given for a system, then a
suitable compensator should be designed so that the overall system will meet the
given specification.
• The compensation schemes used for feedback control system is either series 
compensation or parallel feedback compensation.
The choice between series and parallel compensation
depends on:
1. Nature of signals in the system
2. Power levels at various points
3. Components available
4. D e s ig n e r ’ s experience
5. Economic considerations and so on.
The different types of electrical or electronics compensators used are
? Lag compensator
? Lead compensator
? Lag-lead compensator
In control systems, compensation is required in
the following
situations,
• When the system is absolutely unstable, then compensation is required to stabilize the system and also to meet
the desired performance.
• When the system is stable, compensation is provided to obtain the desired performance.
? The systems with type number 2 and above are usually absolutely unstable systems. Hence for systems with
type number 2 and above, lead compensation is required, because the lead compensator increases
the margin of stability.
? In the systems with type number 1 or 0, stability is achieved by adjusting the gain. In such cases any of the three
compensators may be used to obtain the desired performance.
Page 5


COMPENSATORS
? Types of compensators
? S-Plane representation of compensator
? Comparision of Compensators
Compensator
• The control system are designed to perform specific tasks. The requirement of a
control system are usually specified as performance specifications.
• The specifications related to accuracy, relative stability and speed of the response.
The design problem may be stated as follows:
• When a set of specifications are given for a system, then a
suitable compensator should be designed so that the overall system will meet the
given specification.
• The compensation schemes used for feedback control system is either series 
compensation or parallel feedback compensation.
The choice between series and parallel compensation
depends on:
1. Nature of signals in the system
2. Power levels at various points
3. Components available
4. D e s ig n e r ’ s experience
5. Economic considerations and so on.
The different types of electrical or electronics compensators used are
? Lag compensator
? Lead compensator
? Lag-lead compensator
In control systems, compensation is required in
the following
situations,
• When the system is absolutely unstable, then compensation is required to stabilize the system and also to meet
the desired performance.
• When the system is stable, compensation is provided to obtain the desired performance.
? The systems with type number 2 and above are usually absolutely unstable systems. Hence for systems with
type number 2 and above, lead compensation is required, because the lead compensator increases
the margin of stability.
? In the systems with type number 1 or 0, stability is achieved by adjusting the gain. In such cases any of the three
compensators may be used to obtain the desired performance.
Realization of lag compensator using electrical
network: