Aims: To introduce and analyse electrical machines and switched-mode power-electronic converters which make up the low- to medium-power machine-drive systems that are widely used for motion control, automated manufacturing, and in aerospace and automotive applications.
After completing this unit, students should be able to:
(i) explain the construction, action and operation of a number of types of dc and ac machines; model and analyse the machines to characterise steady-state and quasi steady-state performance; analyse the requirements of typical loads in terms of torque, speed and duty-cycle, and relate these requirements to the selection of a particular machine.
(ii) recognise and explain the operation of a number of power converter topologies commonly used for machine and actuator control; model and analyse the power converters to characterise steady-state and dynamic performance; compare different control methods; and identify salient performance limitations imposed by such factors as power-semiconductor-device, power-source and machine characteristics.
Application of the information, techniques and methods discussed in the lectures, to the proposal of and the carrying through of appropriate solutions to engineering problems in power electronics and drives. Taught, facilitated and tested.
Electrical machines: construction, action and variable speed operational characteristics of conventional and brushless dc machines, polyphase induction machines and dc and ac servomotors and transducers.
Application of machines: analysis of load torque and speed requirements, gearing, regeneration and braking, duty-cycle and rating.
Power converters: DC-to-DC choppers, single and three-phase inverters, basic design calculations, review of control methods, provisional controller design, and assessment of steady-state and dynamic performance.
Power semiconductor devices: power MOSFET, IGBT, fast-recovery diode, salient device characteristics, basic sizing calculations, application at high switching-frequency.