This paper describes the study and experimental verification of sensorless control of permanent magnet synchronous motors with a high precision drive using two novel estimation methods. All the studies of the modified Luenberger observer, reference model, and unscented Kalman filter are presented with algorithm details. The main part determines trials with a full range of reference speeds with a special near-zero speed area taken into account. In order to compare the estimation performances of the observers, both are designed for the same motor and control system and run in the same environment. The experimental results indicate that the presented methods are capable of tracking the actual values of speed and motor position with small deviation, sufficient for precise control.

This paper presents an application of an Unscented- and a Fuzzy Unscented- Kalman Filter (UKF and FUKF) to the estimation of mechanical state variables and parameters in a drive system with an elastic connection. The cascade control structure incorporating an IP controller supported by two additional feedbacks and suitable adaptation mechanism is investigated in this study. The coefficients of the control structure are retuned on the basis of the value of mechanical parameters estimated by filter. The effectiveness of the proposed approaches (classical and fuzzy) is researched through simulation and experimental tests.

Permanent magnet synchronous motor drives Permanent magnet synchronous motorThe Permanent Magnet Synchronous Motor is a rotating electric machine where the stator is a classic three phase coils like that of an induction motor and the permanent magnets are located on the rotor surface. A PMSM provides rotation at a fixed speed in synchronization with the frequency of the power source, regardless of the fluctuation of the load or line voltage. The motor runs at a fixed speed synchronous with mains frequency, at any torque up to the motor's operating limit. The PMSM consist stator windings and rotor permanent magnets sinusoidally distributed so Field Oriented Control can be used (Vas, 1990). From a control point of view, FOC is transfer and extension of DC motor control theory into PMSM. The basic concept is control by a excitation field and armature field-current (Vas, 1990). This type of machines are extensively used in servo drives for low power machine tool, e.g. robots, positioning devices etc. They are receiving increased attention by possibility to use in the region of larger power e.g. electricity generation. The following requirements for servo drives must be served:• high possible power to weight ratio, • large torque to inertia ratio -high acceleration possible, • smooth torque in wide speed -small pulsation of speed, • full torque at zero speed -stand still working, • high speed operation, • compact design and small size. New types of Permanent Magnet materials offer the ability to design electromagnetic energy converters with complicated shapes. Permanent magnets can be sticked or inserted to the small rotor. Rare-earth magnets are mostly used in modern drive. It can be obtained air-gap flux density in range of 1 T. PMSM are used in high-accuracy direct-drive applications mainly due to their advantages. Compared to conventional DC motors, they have no brushes or mechanical commutators, which eliminates the problems due to mechanical wear of the moving parts. In addition, the better heat dissipation characteristic and ability to operate at high speed render them superior to the PMSM drives. Vector control scheme of PMSMThe control scheme of PMSM is relative simple, proposed scheme is presented on Figure 2. www.intechopen.com The field-oriented controller is based on a current-controlled voltage source inverter structure (Vas, 1990;Janiszewski 2004;Terorde, 2002). The current control loops are arranged in the 2-phase synchronously rotating rotor reference frame d-q aligned with rotor flux (also rotor position g), while the rotor position and speed detection operates in the 2-phase stationary reference frame α . The dq-phase arrangement PMSM machine is similar to DC machine in operation. The excitation flux (Ψf) is frozen to the direct axis of the rotor and is associated with d axis. Equivalent of armature current in DC machine is associated with current in q axis. There is also assumed that the effect of any magnetic saturation is neglected during working and thus for modelling purposes the permanent ma...

This paper describes a study and the experimental verification of sensorless control of permanent magnet synchronous motors using Kalman filters. There are proposed two structures, extended and unscented Kalman filters, which use only the measurement of the motor current for on-line estimation of speed, rotor position and load torque reconstruction. The Kalman filter is an optimal state estimator and is usually applied to a dynamic system that involves a random noise environment. These structures are described in detail, starting with the selection of the variables state vector, the filters structure, and ending with in-depth laboratory tests. It has become possible, without using position and torque sensors, to apply these control structures as a cost-effective solution. Experimental results confirm the validity of the proposed estimation techniques.

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Permanent magnet synchronous motor drives Permanent magnet synchronous motorThe Permanent Magnet Synchronous Motor is a rotating electric machine where the stator is a classic three phase coils like that of an induction motor and the permanent magnets are located on the rotor surface. A PMSM provides rotation at a fixed speed in synchronization with the frequency of the power source, regardless of the fluctuation of the load or line voltage. The motor runs at a fixed speed synchronous with mains frequency, at any torque up to the motor's operating limit. The PMSM consist stator windings and rotor permanent magnets sinusoidally distributed so Field Oriented Control can be used (Vas, 1990). From a control point of view, FOC is transfer and extension of DC motor control theory into PMSM. The basic concept is control by a excitation field and armature field-current (Vas, 1990). This type of machines are extensively used in servo drives for low power machine tool, e.g. robots, positioning devices etc. They are receiving increased attention by possibility to use in the region of larger power e.g. electricity generation. The following requirements for servo drives must be served:• high possible power to weight ratio, • large torque to inertia ratio -high acceleration possible, • smooth torque in wide speed -small pulsation of speed, • full torque at zero speed -stand still working, • high speed operation, • compact design and small size. New types of Permanent Magnet materials offer the ability to design electromagnetic energy converters with complicated shapes. Permanent magnets can be sticked or inserted to the small rotor. Rare-earth magnets are mostly used in modern drive. It can be obtained air-gap flux density in range of 1 T. PMSM are used in high-accuracy direct-drive applications mainly due to their advantages. Compared to conventional DC motors, they have no brushes or mechanical commutators, which eliminates the problems due to mechanical wear of the moving parts. In addition, the better heat dissipation characteristic and ability to operate at high speed render them superior to the PMSM drives. Vector control scheme of PMSMThe control scheme of PMSM is relative simple, proposed scheme is presented on Figure 2. www.intechopen.com The field-oriented controller is based on a current-controlled voltage source inverter structure (Vas, 1990;Janiszewski 2004;Terorde, 2002). The current control loops are arranged in the 2-phase synchronously rotating rotor reference frame d-q aligned with rotor flux (also rotor position g), while the rotor position and speed detection operates in the 2-phase stationary reference frame α . The dq-phase arrangement PMSM machine is similar to DC machine in operation. The excitation flux (Ψf) is frozen to the direct axis of the rotor and is associated with d axis. Equivalent of armature current in DC machine is associated with current in q axis. There is also assumed that the effect of any magnetic saturation is neglected during working and thus for modelling purposes the permanent ma...