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

Sensorless Speed Direct Torque Control with Space Vector Modulation (DTC-SVM)
Chapter 6
DIRECT TORQUE CONTROL WITH SPACE VECTOR MODULATION (DTC-
SVM) OF PMSM DRIVE WITHOUT MOTION SENSOR
6.1 Introduction
Many motion control applications, such as material handling, packaging and hydraulic
or pneumatic cylinder replacement, require the use of a position transducer for speed or
position feedback, such as an encoder or resolver. In addition, permanent magnet
synchronous motors require position feedback to perform commutation. Some of
systems utilize velocity transducer as well. These sensor add cost, weight, and reduce
the reliability of the system. Also, a special mechanical arrangement needs to be made
for mounting the position sensors. An extra signal wires are required from the sensor to
the controller. Additionally, some type of position sensors are temperature sensitive and
their accuracy degrades, when the system temperature exceed the limits. Therefore, the
research in the area of sensorless speed control of PMSM is beneficial because of the
elimination of the feedback wiring, reduced cost, and improved reliability.
Sensorless speed DTC-SVM control block scheme is presented in Fig. 6.1.
Figure 6.1. Block scheme of DTC-SVM for PMSM drive without motion sensor.
As we can see the operation of speed controlled PMSM drive without mechanical
motion sensor is based only on measurement of following signals, which are available
in every PWM inverter-fed drive system as:
• DC link voltage,
• motor phase currents,
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