Low And Zero Speed Sensorless

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Low and Zero Speed Sensorless Control of PMSM by Signal Injection Methods

Table of Contents




4.The permanent magnet synchronous motor4

5.Model of the permanent magnet synchronous motor3

6.Sensorless control of p m s m drives4

Methods of sensorless rotor position detection.3

Back EMF Method4

Signal Injection Method4

Theory signal injection4

Superposition injection4

Pattern of Pulse-width modulation (PWM)4

7.Recent experiment in this report4

Signal injection methods4

Model Reference Adaptive control (MRAC)4



1. Nomenclature

= a phase voltage (volt)

= b phase voltage (volt)

= c phase voltage (volt)

= d axis voltages (volt)

= q axis voltages (volt)

= stator resistance (ohme)

= a phase current (amperes)

= b phase current (amperes)

= c phase current (amperes)

= q axis curent (amperes)

= q axis crurent (amperes)

= q axis inductances (henrys)

= d axis inductances (henrys)

= a phase flux linkages (webers)

= b phase flux linkages (webers)

= c phase flux linkages (webers)

= d axis flux linkages (webers)

= q axis flux linkages (webers)

= the rotor position

The permanent magnetic flux (webers)

= rotor speed (rad/sec)

= angle between the rotor and phase A(radians)

= derivative operator

= estimate value

= the gain parameter


The efficiency and accuracy of sensorless control in the permanent magnet synchronous motor (PMSM) needs to be accurate to know the flux flow and the position of rotor, as well as speed of the motor. In this paper, many things about methods of the sensorless have been reported, which works by back EMF within the mid and high speed, and also works by the injection of high frequency signal in the event of inability to detect the position of rotor by back EMF at low or zero speed. These methods have been explained and how each one works and the technique of detecting the rotor position. Method of injection with high frequency signal has also been mentioned in some details for example, types, principle, common one, and difference between these types. These ways are (superposition) which installs high frequency on the top of the fundamental voltage wave entering the motor or by editing pattern of Pulse-width modulation (PWM). The superposition method has been chosen for the process that will be applied in this is project. In this paper it has also been clarified the instruction, types, and theory of work of permanent magnet synchronous motor (PMSM). The PMSM has salient roles that have been selected as the examples in this report. The PMSM is represented mathematically, stated equations were important and which are used in this report. The method of control to determine the rotor position and speed is reported generally, the Model Reference Adaptive Control (MRAC) is mentioned in this report in details which will be used for future project.


In recent years, Synchronous Motors with Permanent Magnet (PMSM) have been increasingly attractive for application in industrial drives. This motor can be operated in four quadrants. There are a lot of advantages of this motor such as low harmonics, high output power and torque. It also has high efficiency because there are not brushes, slip-rings, and rotor copper ...