Variable-speed AC drives are nowadays based on three-phase electrical machines fed by power electronic converters acting as power interface between the electrical machine and AC or DC power sources. Nevertheless, in the last two decades the multiphase electrical drives have become an interesting alternative for particular applications. However, the application of multiphase drives is still limited, mainly due to their complexity and control that somehow make them more difficult to handle with respect to the conventional three-phase counterparts. Therefore, this work intends to be a useful tool to disseminate the fundamental concepts of multiphase drives to students and application engineers.

Chapter Contents:

• 16.1 Introduction
• 16.1.1 Definition of a multiphase drive
• 16.1.2 Advantages of multiphase drives
• 16.1.3 A brief history of multiphase motor drives
• 16.1.4 Applications
• 16.2 Multiphase electrical machines
• 16.2.1 VSD approach
• 16.2.1.1 Symmetrical machines
• 16.2.1.2 Asymmetrical machines
• 16.2.1.3 Features of VSD approach
• 16.2.1.4 Case study 1: asymmetrical six-phase IM
• 16.2.1.5 Case study 2: asymmetrical IPM machine
• 16.2.2 Multi-stator approach
• 16.2.2.1 Case study 3: asymmetrical 12-phase IM
• 16.2.3 Summary on multiphase machines
• 16.3 Multiphase power converters
• 16.3.1 Modulation strategies for multiphase inverters
• 16.3.2 Pulse width modulation
• 16.3.3 Voltage limits
• 16.3.3.1 Case study: sinusoidal operating conditions
• 16.3.3.2 Case study: five-phase inverters
• 16.3.3.3 Case study: seven-phase inverters
• 16.3.3.4 Effect of the zero-sequence component on the power losses
• 16.3.4 Space vector modulation
• 16.3.5 Analysis of the output current ripple
• 16.4 Control of multiphase drives
• 16.4.1 Field-oriented control
• 16.4.2 Direct torque control
• 16.4.3 Direct flux vector control
• 16.4.4 Model predictive control
• 16.5 Summary
• List of symbols
• Glossary of terms
• References

Inspec keywords: variable speed drives; reviews; machine control; AC motor drives

Other keywords: variable-speed AC drives; multiphase electrical drives; control; multiphase machine drives

Subjects: Drives; Control of electric power systems; a.c. machines