Control of Synchronous Motors

Chapter 1

Synchronous motor controls, Problems and Modeling ¹

1.1. Introduction

The tremendous importance of rotary synchronous motors in the industrial systems control has been recalled in the general introduction of this book. There is in the professional community a very important emulation to define control structures, simple to materially implant and to design and very efficient ([BOS 86, LEO 90, VAS 90, MIL 89, LEP 90, LAC 94, LAJ 95, GRE 97, LOU 99, STU 00b, LOU 04c, LOU 09]). Nowadays, we can consider that the control structures are based on some very solid basic principles that we will present. Of course, from one designer to another, many alternatives can appear (each manufacturer wants to have their own patents), but we can consider that the basic principles exploited in practice are those that will be covered in Chapters 2 and 3 of this book, which are devoted to the torque controls. The most important key concepts will be: “self-control”, torque control in the “natural” reference frame (often known as the a-b-c reference frame); torque control in the rotor reference frame (often known as “Park reference frame” or d-q reference frame). Indeed, when the torque control is carried out, it is easy to successively implant a speed control, to obtain a device usually called an “electronic speed variator” and then if necessary, a position control. These last questions will be tackled in Chapter 4. This chapter exposes a general modeling of the synchronous motors and is particularly ...