This chapter gives an overview of three widely used machines of the full range of power spectrum. Steady-state torque-speed boundaries in all four quadrants within and above the base speed for the major types of conventional DC and AC machines are introduced first, followed by the dynamic models of these machines. A limited, by no means complete, analysis of the two dominant types of AC machine (the AC induction and the synchronous) dynamics is included with a view to guide the reader to appreciate the necessity for transformations of voltages and currents and flux linkages of a three-phase machine to one of the rotating axes, in order to appreciate how current controls are used for controlling the torque and flux linkages independently of each other. The logical control structures, the RFOC, for these machines then follow for each machine type. This is followed by a brief description of sensor technologies and associated hardware. Finally an overview of recent developments in the AC induction and PM synchronous machines is included.

Chapter Contents:

• 2.1 Introduction
• 2.2 Electric machines and torque–speed (T–ω) boundaries
• 2.3 T–ω characteristics within torque–speed boundaries
• 2.4 Dynamic models of machines and simulation
• 2.4.1 Dynamic model of DC machines
• 2.4.2 Dynamics model of synchronous machines in rotor reference frame [1]
• 2.4.2.1 Machine inductance and flux linkages
• 2.4.2.2 Voltage equations
• 2.4.2.3 Rotor flux-oriented control (RFOC) or vector control [2,3]
• 2.4.3 Dynamic model of induction machines in synchronous reference frame
• 2.4.3.1 Machine inductance and flux linkages
• 2.4.3.2 Voltage, developed power and torque equations
• 2.4.3.3 Conditions for rotor flux-oriented control
• 2.5 Simulation of drive systems
• 2.5.1 Tuning of an electric drive using a cascaded structure [4]
• 2.5.2 Voltage reference amplitude limitation
• 2.5.3 Pulse-width modulation block
• 2.6 Sensors in drive systems
• 2.6.1 Current sensors for electric drive systems
• 2.6.2 Speed sensors for electric drive systems
• 2.7 Recent developments in PM machines; with reference to developments of other types: DCM and IM
• 2.7.1 Developments in winding topologies
• 2.7.2 Emerging electric machine topologies
• 2.7.3 Permanent magnet synchronous machines (PMSMs) with deep flux weakening capability
• 2.7.4 Control of the PMSM at deep flux weakening
• 2.8 Summary
• List of symbol
• Glossary of terms
• References

Inspec keywords: machine control; induction motor drives; sensors; DC motor drives; synchronous motor drives; torque control

Other keywords: rotating axes; dynamic models; three-phase machine; DC machine; voltage transformation; drive systems; flux linkage control; PM synchronous machine; current transformation; torque control; electric machines; power spectrum; steady-state torque-speed boundaries; AC machine; sensor technologies; AC induction machine

Subjects: Control of electric power systems; Sensing devices and transducers; Transducers and sensing devices; Asynchronous machines; Mechanical variables control; Synchronous machines; Drives; d.c. machines