H. Børsting

Sensorless field oriented control of a PM motor including zero speed

This paper presents a simple control method for controlling permanent magnet synchronous motors (PMSM) in a wide speed range without a shaft sensor. The method estimates the stator flux by integration of the measured BEMF signal. To compensate for the offset in the BEMF the offset is estimated. The control method is made robust at zero and low speed by changing the direct vector current component to a value different from zero. In order to verity the applicability of the method the controller has been implemented and tested on a 800 W motor.

Rotor field oriented control with adaptive iron loss compensation

It is well known from the literature that iron loses in an induction motor implies field angle estimation errors and hence detuning problems. In this paper, a new method for estimating the iron loss resistor in an induction motor is presented. The method is based on a traditional dynamic model of the motor referenced to the rotor magnetizing current, and with the extension of an iron loss resistor added in parallel to the magnetizing inductance. The resistor estimator is based on the observation that the actual applied stator voltages deviates from the voltage estimated, when a motor is current controlled in a field oriented control scheme. This deviation is used to force an MIT-rule based adaptive estimator. An adaptive compensator containing the developed estimator is introduced and verified by simulations and tested by real time experiments.

Adaptive observer for speed sensorless PM motor control

This paper presents an adaptive observer for estimating the rotor position and speed of a permanent magnet synchronous motors (PMSM). The observer compensates for voltage offsets and permanent magnet strength variations. The adaptation structure for estimating the strength of the permanent magnet is determined from a Lyapunov stability proof. The observer estimates the stator flux by integration of the measured BEMF signal. In order to verify the applicability of the method the observer has been implemented and tested on a 800 W motor.

Estimation of Physical Parameters in Induction Motors

Abstract Parameter estimation in induction motors is a field of great interest, because accurate models are needed for robust dynamic control of induction motors. In this paper physical parameters in a continuous-time model structure of the motor are estimated. The physical parameters are estimated, using a continuous-discrete version of the prediction error method based on an innovations model structure. In order to reduce the large number of unknown parameters in the stochastic part of the innovations model, the model is replaced by an output error model. Experimentai results show that the model identified is improved, compared to motor models obtained from standard methods based on steady state measurements. All the results in this paper are based on experiments, carried out on a laboratory setup.

Full adaptive backstepping design of a speed sensorless field oriented controller for an induction motor

It is well known that modern induction motor control relies on a good dynamic model of the motor. Full state variable information together with exact parameter knowledge is needed. The aim of this work is to fulfil these needs by use of a novel nonlinear observer structure based on the backstepping principle. A full proof for convergence of states is presented together with a stability proof for the parameter estimates. When the system is persistently excited, simulations and experiments show convergence of the parameters. The observer is used in a rotor field oriented control strategy and verified by experiments.

Adaptive sensorless field oriented control of PM motors including zero speed

This paper presents a simple control method for controlling permanent magnet synchronous motors (PMSM) in a wide speed range without a shaft sensor. An adaptive observer is used for estimation of the rotor position and speed of a permanent magnet synchronous motors (PMSM). The observer compensates for voltage offsets and permanent magnet strength variations. The adaptation structure for estimating the strength of the permanent magnet is determined from a Lyapunov stability proof. The control method is made robust at zero and low speed by changing the direct vector current component to a value different from zero. In order to verify the applicability of the method the controller has been implemented and tested on a 800 W motor.

Speed sensorless field oriented control of an induction motor at zero speed with identification of inverter model parameters

Using adaptive Lyapunov design a new approach for the design of an observer for speed sensorless control is developed. The resulting scheme leads to a nonlinear full order observer for the motor states and for the motor and inverter parameters including the rotor speed. Assuming motor parameters are known, the design achieves stability with a guaranteed region of attraction. Experiments demonstrate high dynamic performance even at zero rotor speed based only on the slip frequency caused by the load torque.

Nonlinear control of induction motors: a performance study

An approach to control of induction motors, based on nonlinear state feedback has previously been presented by the authors (1997). The resulting scheme gives a linearized input-output decoupling of the torque and the amplitude of the field. The proposed approach is used to design controllers for the field amplitude and the motor torque. The method is compared with the traditional rotor field oriented control method as regards variations in rotor resistance an magnetizing inductance.