Sensorless Control Of Permanent Magnet Synchronous Motor Research Articles

Sensorless Control of PMSM with Compensated Sliding Mode Observer

This paper presents a research on sensorless control of Permanent-magnet Synchronous Motor (PMSM) based on a compensated sliding mode observer (C-SMO) using one Hall sensor. Generally the sliding mode observer (SMO) has an attractive robustness to disturbances, and parameter variations in relatively high speed region. But the SMO cannot help reducing the ripple or chattering components of the estimated currents and the estimated phase especially in the low speed region. The estimated rotary speed is the differential result of the estimated phase. So the noise of the estimated phase is amplified in the estimated rotary speed which is used in speed closed-loop control and the low pass filter. The PMSM cannot be started with traditional SMO under closed-loop control condition. A more accurate estimated speed and a phase reference may solve this problem and they can be estimated by the Hall sensor. This more accurate estimated speed can also help the PMSM achieve a better performance on rotor phase estimation. The C-SMO which combines the advantages of Hall sensor and SMO achieves a less noise, less vibration effect. And the PMSM can be started with C-SMO under closed-loop control condition. The comparison between the SMO and C-SMO is realized by Matlab/Simulink and the simulation results show the effectiveness of the proposed algorithm for the sensorless drive system of a PMSM.

Sensorless direct torque control for salient-pole PMSM based on extended Kalman filter fed by AC/DC/AC converter

In this paper, a new sensorless interior permanent magnet synchronous motor (IPMSM) drives method with extended Kalman filter (EKF) for speed, rotor position and load torque estimation is proposed. The direct torque control (DTC) technique for permanent magnet synchronous motor (PMSM) is receiving increasing attention due to the important advantages of the low dependence on motor parameters when compared with other motor control techniques. The Kalman filter is an observer for linear and non-linear systems and is based on the stochastic intromission, in others words, noise. The PMSM is fed by an indirect power electronic converter which is controlled by a sliding mode technique. The simulation tests performed for different operating conditions have confirmed the robustness of the overall system; and it is shown that the sliding mode technique has successfully minimized the different harmonics introduced by the line converter.

Sensorless Control of PMSM Based on Low-Frequency Current Signal Injection in the Direct Axis at Low and Zero Speed

A novel sensorless control method of permanent magnet synchronous motor (PMSM) based on low frequency (LF) current signal injection is proposed in this paper. A LF sinusoidal current signal is superimposed into the estimated d-axis, and the corresponding voltage response and current response are detected to estimate the rotor speed and the rotor position. This method doesn't rely on the non-ideal features but just the fundamental model of PMSM. As a result, the introduced method can be applied to not only IPMSM, but also to SPMSM. Theoretical analysis and simulation results are carried out. The simulation results indicate that the rotor position and speed can be obtained exactly at low and zero speed. The approach ensures good dynamic and static performances, and can realize accurate position servo control.

High-Performance Sensorless Control of PMSM Based on Sliding Mode Current Observer

The sensorless vector control system of permanent magnet synchronous motor (PMSM) is a system with uncertainty and external disturbance. According to sliding mode control theory, this paper realized robust control of the uncertainty and external interference by use of the equivalent control matched with switching control. Meanwhile, in order to eliminate the adverse effect produced by the chattering of the sliding mode, this paper adopts the saturation function of quasi-sliding mode instead of the traditional sign function. Furthermore, the exponential reaching law is used to further weaken the chattering and to ensure the rapidity of the system. Simulation and experimentation show that this control method has good dynamic and static performance.

A High-Speed Sliding-Mode Observer for the Sensorless Speed Control of a PMSM

This paper proposes a sensorless speed control strategy for a permanent-magnet synchronous motor (PMSM) based on a new sliding-mode observer (SMO), which substitutes a sigmoid function for the signum function with a variable boundary layer. In order to apply a sensorless PMSM control which is robust against parameter fluctuations and disturbances, a high-speed SMO is proposed, which estimates the rotor position and the angular velocity from the back EMF. In the conventional SMO, a low-pass filter and an additional position compensation of the rotor are used to reduce the chattering problem that is commonly found in the SMO using the signum function. In order to overcome the time delay caused by the low-pass filter, in this research, a sigmoid function is used for the switching function instead of the signum function. Also, the variation in the stator resistance is estimated to improve the steady-state performance of the SMO. The stability of the proposed SMO was verified using the Lyapunov second method to determine the observer gain. The validity of the proposed high-speed PMSM sensorless velocity control has been demonstrated with simulations and real experiments.

Sensorless Direct Torque Control of PMSM using Unsected Kalman Filter

AbstractThis paper considers the sensorless direct torque control of a Permanent Magnet Synchronous Motor (PMSM) by using Unscented Kalman Filtering (UKF) to estimate the flux-linkage, the rotor speed and the position. UKF adapts the unscented transformation (UT) algorithm and symmetrical sampling strategy. The UKF algorithm represents a serious strongpoint to the Extended Kalman Filter (EKF) for the highly nonlinear systems. UKF ensures high estimation precision and simple calculation. The sensorless Direct Torque Control (DTC) for PMSM is designed in this paper. The estimating errors when using UKF and EKF are compared. The effectiveness of this method is verified through several simulations. The DTC based on UKF for PMSM has good speed and torque response performances. This method has rapid astringency of estimated error.

고속 슬라이딩모드 관측기를 이용한 PMSM 센서리스 속도제어

The paper proposes a sensorless speed control strategy for a PMSM (Permanent Magnet Synchronous Motor) based on a new SMO (Sliding Mode Observer), which substitutes a signum function with a sigmoid function. To apply robust sensorless control of PMSM against parameter fluctuations and disturbance, the high speed SMO is proposed, which estimates the rotor position and angular velocity from the back EMF. The low-pass filter and additional position compensation of the rotor are used to reduce the chattering problem commonly found in sliding mode observer with signum function, which becomes possible by applying the sigmoid function with the control of a switching function. Also the proposed sliding mode observer with the sigmoid function has better efficiency than the conventional sliding mode observer since it adjusts the observer gain by variable boundary layer and estimates the stator resistance. The stability of the proposed sliding mode observer is verified by the Lyapunov second method in determining the observer gain. The validity of the proposed high speed PMSM sensorless velocity control has been demonstrated by real experiments.

Design and implementation of a novel high-performance sensorless control system for interior permanent magnet synchronous motors

This study proposes a novel high-performance rotor position estimator for an interior permanent magnet synchronous motor (PMSM). By suitably processing the mathematical model of the motor, a systematic method of the rotor position estimating method has been developed. The proposed control system can be used in the space vector pulse-width modulation switching method, which is widely used in industry. By measuring the DC-bus voltage and the phase currents, a systematic rotor position estimator has been developed. Finally, the rotor position and rotor speed are obtained, and a closed-loop control system can be achieved. A digital signal processor, TMS 320F2812, is used to execute the estimating algorithm and control algorithm. As a result, the hardware is very simple. Several experimental results show that both the position control system and the adjustable speed control system are achieved. The system can be adjusted from 1 to 2000 r/min. In addition, by using the proposed position-loop H∞ controller, the position control system can be achieved with satisfactory performance. This study proposes a new method for a sensorless interior PMSM control system.

Enhancement of the Speed Response of PMSM Sensorless Control Using A New Adaptive Sliding Mode Observer

This paper proposes an adaptive sliding mode observer (SMO), which adds the estimation function of the stator resistance to a new sliding mode observer for the robust sensorless control of permanent magnet synchronous motor (PMSM) with variable parameters. To reduce the chattering problem commonly found in the conventional sliding mode observer where the low-pass filter and additional position compensation of the rotor are used, the sigmoid function is used for the control of a switching function in this research. With the estimation of the stator resistance, the proposed observer can improve the control performance by reducing the estimation error of the motor's speed. Note that the stator resistance is varying with the ambient temperature and becomes an error source for the sensorless control of PMSM. The new sliding mode observer has better efficiency than the conventional adaptive sliding mode observer by reducing the time consuming integral calculations. The stability of the proposed adaptive sliding mode observer is verified by the Lyapunov function in determining the observer gains, and the effectiveness of the observer is demonstrated by simulations and experiments.

Sensorless control of PMSM based on adaptive sliding mode observer

A novel speed and position sensorless control method for permanent magnet synchronous motor (PMSM) based on sliding mode observer is presented. In this paper, the sliding mode observer's structure and its design method are described. First, by adopting mathematical model of PMSM in a stationary reference frame, stator currents are observed to achieve the stator speed and position of PMSM by using sliding mode observer. At the same time, the parameter variations of PMSM, the estimated rotor speed and position are obtained through a Lyapunov function. A novel equation is obtained to estimate rotor speed. Finally, simulation results show that the proposed observer can achieve satisfying performance and the feasibility is verified.

Fast response adaptive fuzzy logic controller for sensorless direct torque control of PMSM with minimum torque ripple

PurposeThe paper seeks to provide an adaptive fuzzy logic controller for permanent magnet synchronous motor (PMSM) under direct torque control (DTC) algorithm to minimize the torque ripple.Design/methodology/approachThe design methodology is based on vector control analysis. MATLAB simulations supported with experimental study under C++ are used to execute the proposed work.FindingsThe results show that considerable torque ripple reduction as well as considerable current ripple reduction can be achieved by utilizing adaptive fuzzy switching algorithm to fire the inverter supplying the PMSM.Research limitations/implicationsThis research is limited to PMSM, however the research can be extended to include other AC motors as well. In addition, the following points can be studied, the effects of harmonics in control signals on the torque ripple. Digital and active filters as solution to these harmonics can be also addressed. The actual mathematical relation between the torque ripple and flux ripple can be studied to set the flux and torque bands width in reasonable value.Practical implicationsBased on existence DTC control system, it is only required to change the software‐switching algorithm, to provide smooth torque, given that the switching frequency of the inverter module is more than or equal to 15 kHz and the system is supplied with timers. In addition, a relatively higher DC voltage may be required to achieve higher speed compared with the traditional DTC.Originality/valueIn this paper, the stator flux position, and errors due to deviations from reference values of the torque and stator flux are used to select two active vectors while at the same time the absolute value of the torque error and the stator flux position are fuzzified to adapt the switching of the inverter in order to control the applied average voltage level in such a way as to minimize the torque ripple, so instead of fixed time table structure, a fuzzy logic is used to calculate the switching time for the selected vectors and no PI controller is used as the case in the traditional‐space vector modulation. This work is directed to motor drive system designers who seek highly smooth torque performance with fast response.

Sensorless control of PMSM drive with state and load torque estimation

PurposeThe purpose of this paper is to obtain a fully sensorless permanent magnet synchronous motor (PMSM) drive control algorithm used for robot arm drive with load recognition. The paper shows how to use an extended Kalman filter (EKF) instead of sensors of the mechanical quantities as well as how to adapt the model of the PMSM to the filter procedures and aims at the real time application in the field‐oriented control (FOC) structure of the high‐dynamic drive.Design/methodology/approachThe synthesis of the control system is based on the method of the FOC, theory of the EKF and object description in the form of state equation with suitable choice of state vector. The adequate connection of these three methodologies is a core of the approach to design. First, the control algorithm was tested by means of simulation method then the real laboratory plant was built and investigated.FindingsOwing to task‐oriented formulation of the PMSM model, adequate organization of the EKF procedures and suitable choice of covariance matrices the proper control algorithm was obtained. The algorithm can be applied on DSP and gives a good result for the high dynamic drive in spite of the fact that the Kalman procedures are recognized as a time‐consumed solution of the estimation problem.Research limitations/implicationsThe proposed algorithm can be used also in the case of another type of drive, for instance induction motor drive, although the model of the motor has a different formula. A disadvantage of the method is lack of the general rules for choosing the elements of the covariance matrices.Practical implicationsThe presented algorithm is written in open‐programming language. Obtained results may be important for synthesis of robot arm drive, where the information about load forces is needed.Originality/valueThe paper presents an original sensorless vector control of PMSM with load recognition based on EKF. The originality elements are the choice of the covariance matrix elements and the real‐time realisation of the algorithm on the DSP.

Adaptive observer of rotor speed and position for PMSM sensorless control system

This paper deals with the problem of rotor speed and position detection in sensorless permanent magnet synchronous motor (PMSM) drives. A concept based on detecting the back EMF induced in stator windings was developed and modified. A general structure of an adaptive observer with the proportional‐integral function of a corrector is introduced. The non‐stationary character of the observer presented in this paper requires an adaptive change of observer corrector settings. Such observer structure was implemented on a DSP system and verified experimentally. Both simulation and experimental results show good properties of the proposed observer structure.

Two Sliding Mode Based Observers for Sensorless Control of PMSM Drives

This paper develops two sliding mode-based observers for sensorless control of permanent magnet synchronous motor (PMSM) drives. These observers estimate the rotor position and speed from the stator currents and the DC-link voltage measurements. The first observer uses the f g stator reference, while the second observer uses an estimated dq rotor reference. Both observer structures have two main parts. The first part is a sliding mode-based observer that uses the equivalent control to estimate a disturbance term containing information on the position and speed. The second part is a specific observer used to extract these desired variables. The observer designs the implementation aspects, and a comparative study on the extensive experimental results are given.

Industry application of zero-speed sensorless control techniques for PM synchronous motors

This paper presents the state of the art in the area of industrial applications of sensorless control for permanent-magnet synchronous motor (PMSM) drives. A new emerging technology is becoming mature to come to the market, based on high-frequency signal injection, that makes it possible to achieve zero-speed operation without increasing the complexity and the cost of the system. After an overview of major theoretical principles of sensorless control of PMSMs, the paper focuses on the practical implementation of one of the previously described high-frequency injection techniques in both salient and nonsalient PM machines. Experimental results are presented, including useful hints for practical implementation.