Electromechanical Energy Conversion
Introduction
Chapter 3
Electromechanical Energy
Conversion
Topics to cover:
1. Introduction
3. Force and Torque
5. Friction
2. Electro-Motive Force (EMF)
4. Doubly-Excited Actuators
6. Mechanical Components
Introduction (Cont.)
For energy conversion between electrical and mechanical forms, electromechanical devices are developed. In general, electromechanical energy conversion devices can be divided into three categories: – Transducers (for measurement and control), which transform signals of different forms. Examples are microphones, pickups, and speakers
– Force producing devices (linear motion devices), which produce forces mostly for linear motion drives, such as relays, solenoids (linear actuators), and electromagnets.
– Continuous energy conversion equipment, which operate in rotating mode. A device would be known as a generator if it convert mechanical energy into electrical energy, or as a motor if it does the other way around (from electrical to mechanical).
Lorentz Force & EMF
Lorentz force is the force on a point charge due to electromagnetic fields.
It is given by the following equation in terms of the electric and magnetic fields F q(E vB)
The induced emf in a conductor of length l moving with a speed v in a uniform magnetic field of flux density B can be determined by a e vB dl
b In a coil of N turns, the induced emf can be calculated by e
Concept map of electromechanical system modeling
d dt where is the flux linkage of the coil and the minus sign indicates that the induced current opposes the variation of the field. It makes no difference whether the variation of the flux linkage is a result of the field variation or coil movement.
EMF
EMF
- Example: EMF in a Linear Actuator
- Example Solution
Sketch L(x) and calculate the induced emf in the excitation coil for a linear actuator shown below.
Assuming infinite permeability for the magnetic
Chapter 3
Electromechanical Energy
Conversion
Topics to cover:
1. Introduction
3. Force and Torque
5. Friction
2. Electro-Motive Force (EMF)
4. Doubly-Excited Actuators
6. Mechanical Components
Introduction (Cont.)
For energy conversion between electrical and mechanical forms, electromechanical devices are developed. In general, electromechanical energy conversion devices can be divided into three categories: – Transducers (for measurement and control), which transform signals of different forms. Examples are microphones, pickups, and speakers
– Force producing devices (linear motion devices), which produce forces mostly for linear motion drives, such as relays, solenoids (linear actuators), and electromagnets.
– Continuous energy conversion equipment, which operate in rotating mode. A device would be known as a generator if it convert mechanical energy into electrical energy, or as a motor if it does the other way around (from electrical to mechanical).
Lorentz Force & EMF
Lorentz force is the force on a point charge due to electromagnetic fields.
It is given by the following equation in terms of the electric and magnetic fields F q(E vB)
The induced emf in a conductor of length l moving with a speed v in a uniform magnetic field of flux density B can be determined by a e vB dl
b In a coil of N turns, the induced emf can be calculated by e
Concept map of electromechanical system modeling
d dt where is the flux linkage of the coil and the minus sign indicates that the induced current opposes the variation of the field. It makes no difference whether the variation of the flux linkage is a result of the field variation or coil movement.
EMF
EMF
- Example: EMF in a Linear Actuator
- Example Solution
Sketch L(x) and calculate the induced emf in the excitation coil for a linear actuator shown below.
Assuming infinite permeability for the magnetic