Direct Torque Control with Space Vector Modulation (DTC-SVM) of ...

Control methods of PM Synchronous motor
Chapter 4 CONTROL METHODS OF PM SYNCHRONOUS MOTOR
4.1 Introduction
The basic block scheme of adjustable speed drive with control block for PMSM is
presented in Fig. 4.2. It consists of two parts: power (fat line) and control part
employed microprocessor (thin line). The first one previously have been explained in
chapter 3. The second one will be described bellow.
Figure 4.2. The basic block scheme of PMSM drive supplied voltage source inverter.
The main task of control block is follow demand reference speed by motor and provide
proper operation in static (insight of the limits) and dynamic states without any
instability. This is ensured through suitable generated gate signals for the IGBT
transistor inside of the inverter. Therefore, to make good decision how to control power
transistors in the inverter, the following feedback signals are measured and used:
• DC link voltage,
• motor phase currents,
• speed or position of the rotor.
This significantly improve dynamic behavior of the system (good performance of the
torque and speed response, very fast dynamics response with fully controllable torque in
wide speed range).
The scalar control for PMSM without damper winding (squire cage) is not simple as for
induction motor [39,40]. It requires additional stabilization loop, which can be provide
by feedback loop from: rotor velocity perturbation, active power or DC-link current
perturbation [9].
The vector control method will be described bellow.
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