Search results
1 – 10 of 84T. Orlowska‐Kowalska and M. Dybkowski
This paper aims to obtain an accurate and robust estimation method of the rotor flux and speed for the sensorless induction motor (IM) drive.
Abstract
Purpose
This paper aims to obtain an accurate and robust estimation method of the rotor flux and speed for the sensorless induction motor (IM) drive.
Design/methodology/approach
The reduced order observer has been used as an online tuned rotor flux model in the model reference adaptive system (MRAS) concept applied for the IM speed estimation. The output of this observer was used also as a feedback signal required in the direct field‐oriented control (DFOC) structure of the IM.
Findings
It is shown that a new rotor flux and speed estimator are more robust to motor parameter changes in comparison with the classical MRAS estimator and can work stably in the DFOC structure, in the wide speed range, even for relatively high (50 per cent) identification errors of equivalent circuit parameters of the IM.
Research limitations/implications
The investigation looked mainly at the estimation accuracy performance and whole system stability while economic issues will still need to be addressed.
Practical implications
The proposed new improved MRAS speed estimator can be easily realised using modern digital signal processors. The implementation was tested in an experimental set‐up with floating point DSP used as the system controller. The fixed‐point realisation needs to be developed to obtain the practical application in the industrial drive systems.
Originality/value
The application of the reduced order flux observer as a tuned flux model in the MRAS type speed estimator instead of the simple, but very sensitive to motor parameter uncertainties, current flux model, enables much better accuracy and stability of the rotor speed estimation in the complex DFOC structure than in the case of classical MRAS estimator.
Details
Keywords
Shweta Singh, Amar Nath Tiwari and S.N. Singh
For vector control of permanent magnet synchronous motor (PMSM) requires motor speed and rotor position estimation. The precision of the open-loop techniques of the stator flux…
Abstract
Purpose
For vector control of permanent magnet synchronous motor (PMSM) requires motor speed and rotor position estimation. The precision of the open-loop techniques of the stator flux and speed for vector control PMSM drive drops as mechanical speed decreases. The stator resistance and estimated stator flux values crisscross have a huge effect on the transient and steady-state performance of the drive at lower speed. The framework turns out to be increasingly strong against parameter crisscross and signal noises by using adaptive observers for estimation of speed and flux.
Design/methodology/approach
This paper presents a comparison of two-speed observers for the vector control PMSM drive: the sliding mode observer (SMO) and the model reference adaptive system (MRAS). A comprehensive analysis of SMO and MRAS respects dynamic, steady-state performance and robustness, affectability, stability and computational complexity has been introduced. The abstract of the advantages and disadvantages of both observer and their comparative analysis have also been discussed.
Findings
Dynamic performance steady-state performance and robustness, affectability and stability.
Originality/value
This paper presents a sensorless scheme, namely, MRAS and SMO for control of PMSM drive. These sensorless techniques have been tested for a PMSM motor drive and the motor performance was compared for both techniques. Matlab/Simulink based simulation results conclude that the adaptive methods improve dynamic response, reduces torque ripples and extended speed range.
Details
Keywords
This paper aims to suggest a parameter independent and simple speed estimator for primary field-oriented control of a promising electro-mechanical energy conversion device in the…
Abstract
Purpose
This paper aims to suggest a parameter independent and simple speed estimator for primary field-oriented control of a promising electro-mechanical energy conversion device in the form of brushless doubly-fed reluctance machine (BDFRM) drive.
Design/methodology/approach
The speed estimation algorithm, in this context, is formulated using a modified secondary winding active power (mPs)-based model reference adaptive system (MRAS). The performance of the proposed estimator is verified through computer aided MATLAB simulation study, compared with conventional active power-based MRAS and further supported with experimental validation using a 1.6 kW BDFRM prototype run by a dSPACE-1103 controller.
Findings
The formulation of mPs-MRAS is insensitive to any machine parameters and does not involve any integration/differentiation terms. Thus, any deviation therein does not hinder the performance of the mPs-MRAS-based speed estimator. The proposed speed estimator shows stable behavior for variable speed-constant load torque operation in all the four quadrants.
Originality/value
The formulation of mPs-MRAS is insensitive to any machine parameter and does not involve any integration/differentiation terms.
Details
Keywords
Aymen Omari, Bousserhane Ismail Khalil, Abdeldjebar Hazzab, Bousmaha Bouchiba and Fayssal ElYamani Benmohamed
The major disadvantage of the field-oriented control (FOC) scheme of induction motors is its dependency on motor parameter variations because of the temperature rise. Among the…
Abstract
Purpose
The major disadvantage of the field-oriented control (FOC) scheme of induction motors is its dependency on motor parameter variations because of the temperature rise. Among the motor parameters, rotor resistance is a parameter that can degrade the robustness of FOC scheme. An inaccurate setting of the rotor resistance in the slip frequency may result in undesirable cross coupling and performance degradation. To overcome this disadvantage, the purpose of this paper is to propose a model reference adaptive system (MRAS) rotor time constant tuning to improve the induction motor drive performance and to compensate the flux orientation error in vector control law.
Design/methodology/approach
First, the dynamic model and the indirect field-oriented control of induction motor are derived. Then, an inverse rotor time constant tuning is proposed based on MRAS theory where a new adaptation signal formulation is used as reference model, and the estimated stator currents obtained from induction motors (IM) state space resolution is used in the adaptive model.
Findings
The effectiveness and robustness of IM speed control with the proposed MRAS inverse rotor time constant estimator is verified through MATrix LABoratory/Simulink model simulation and laboratory experimental results. The simulation and experimental results show good transient drive performances, satisfactory for rotor resistance estimation and robustness with regard to uncertainties and load torque disturbance.
Originality/value
This paper presents an online tuning of the inverse rotor time constant using a new adaptation signal MRAS model. The proposed estimator is proved to guarantee the stability for different operating conditions, especially in very low/zero speed region and heavy load torque. The stability analysis of the proposed estimation procedure is also demonstrated.
Details
Keywords
F.E. Benmohamed, I.K. Bousserhane, A. Kechich, B. Bessaih and A. Boucheta
The end-effects is a well-recognized phenomenon occurring in the linear induction motor (LIM) which makes the analysis and control of the LIM with good performance very difficult…
Abstract
Purpose
The end-effects is a well-recognized phenomenon occurring in the linear induction motor (LIM) which makes the analysis and control of the LIM with good performance very difficult and can cause additional significant non-linearities in the model. So, the compensation of parameters uncertainties due to these effects in the control system is very necessary to get a robust speed control. The purpose of this paper is to propose a new technique of LIM end-effects estimation using the inverse rotor time constant tuning in order to compensate the flux orientation error in the indirect field-oriented control (IFOC) control law.
Design/methodology/approach
First, the dynamic model of the LIM taking into consideration the end-effects based on Duncan model is derived. Then, the IFOC for LIM speed control with end-effects compensation is derived. Finally, a new technique of LIM end-effects estimation is proposed based on the model reference adaptive system (MRAS) theory using the instantaneous active power and the estimated stator currents vector. These estimated currents are obtained through the solution of LIM state equations.
Findings
Simulations were carried out in MATLAB/SIMULINK to demonstrate the effectiveness and robustness of LIM speed control with the proposed MRAS inverse rotor time constant tuning to estimate end-effects value. The numerical validation results show that the proposed scheme permits the drive to achieve good dynamic performance, satisfactory for the estimated end-effects of the LIM model and robustness to uncertainties.
Originality/value
The end-effects causes a drop in the magnetizing, primary and the secondary inductance, requiring a more complex LIM control scheme. This paper presents a new approach of LIM end-effect estimation based on the online adaptation and tuning of the LIM inductances. The proposed scheme use the inverse rotor time constant tuning for end-effects correction in LIM vector control block.
Details
Keywords
Ena Vejnovic, Sharon Purchase and Liudmila Tarabashkina
To this date, research on tensions has been carried out on business networks and value co-creation, with no studies exploring tensions within the marketing services context. This…
Abstract
Purpose
To this date, research on tensions has been carried out on business networks and value co-creation, with no studies exploring tensions within the marketing services context. This study aims to use the three tension categories proposed by Toth et al. (2018) and Pressey and Vanharanta (2006) to address this gap by identifying the tensions experienced in the market research agency (MRA), creative agency (CA) and client relationship, as well as the processes that increase or minimize these tensions.
Design/methodology/approach
A total of 25 in-depth interviews were carried out with MRA, CA and client employees. NVivo 12 was used to conduct a thematic analysis to identify the overarching processes that influenced tensions.
Findings
Six second-order codes were identified, designating processes that exacerbated or minimized each of the three tensions experienced. Two new processes were identified (“adopting governance processes” and “aspects of identity formation”) which have not been previously reported. An empirical framework was developed pinpointing processes that influenced each tension category, also highlighting complex interdependencies between behavioral, emotional and structural tensions.
Originality/value
This study presents the perspectives of all actors within the marketing services triad providing a more nuanced understanding of tensions at the triadic level, as previous literature predominantly focused either on dyads or on networks. Furthermore, this study highlights important interdependencies between tension categories, providing novel contributions, as well as directions for future research.
Details
Keywords
– The purpose of this paper is to present a two-loop approach for velocity control of a permanent magnet synchronous motor (PMSM) under mechanical uncertainties.
Abstract
Purpose
The purpose of this paper is to present a two-loop approach for velocity control of a permanent magnet synchronous motor (PMSM) under mechanical uncertainties.
Design/methodology/approach
The inner loop calculates the two-axis stator reference voltages through a feedback linearization method. The outer loop employs an RST control structure to compute the q-axis stator reference current. To increase the robustness of the proposed method, the RST controller parameters are adapted through a fractional order model reference adaptive system (FO-MRAS). The fractional order gradient and Lyapunov methods are utilized as adaptation mechanisms.
Findings
The effect of the fractional order derivative in the load disturbance rejection, transient response speed and the robustness is verified through computer simulations. The simulation results show the effectiveness of the proposed method against the external torque and mechanical parameters uncertainties.
Originality/value
The proposed FO-MRAS based on Lyapunov adaptation mechanism is proposed for the first time. Moreover, application of the FO-MRAS for velocity control of PMSM is presented for the first time.
Details
Keywords
Through an illustrative case study, the paper seeks to demonstrate the implementation and use of new performance improvement software.
Abstract
Purpose
Through an illustrative case study, the paper seeks to demonstrate the implementation and use of new performance improvement software.
Design/methodology/approach
Past research in the field of performance measurement and management has tended to focus on what to measure. The reality, though, is that most of the value in performance measurement lies not in the measures selected, nor even in how the data are presented visually (using SPC where applicable) but in the decisions and actions that flow from insights provided. Deriving maximum value from performance measurement requires linking powerful insights from data to appropriate decision making, action and feedback.
Findings
Especially in situations of fast‐moving, operational data, it is possible to improve rates of innovation, adaptation and learning in organizations dramatically through a combination of: implementing the new genre of performance improvement software that currently has no name; structuring and enabling the performance planning and review process; and creating the necessary updraught of management attention.
Originality/value
This paper describes the impact of a new genre of performance improvement software implemented alongside novel concepts in performance planning and review. Performance measurement and management frameworks are analogous to new washing machines in the sense that they need to be properly plumbed‐in, connected‐up and switched‐on before they can deliver value. Given that achieving faster rates of innovation, adaptation and learning is now widely recognized as a key challenge for the coming decade, the message is that “plumbed‐in performance improvement” offers huge potential benefits for organizations that spot the opportunity first.
Details
Keywords
Alan Meekings, Simon Povey and Andy Neely
The purpose of this paper is to explore the concept of performance plumbing, arguing that too often performance management systems in organisations are not correctly installed…
Abstract
Purpose
The purpose of this paper is to explore the concept of performance plumbing, arguing that too often performance management systems in organisations are not correctly installed. Without the appropriate plumbing, performance management systems do not drive organisational change and improvement.
Design/methodology/approach
The paper draws on the consultancy experiences of two of the authors, as well as the research of the third. Specific case examples are provided throughout the paper to illustrate the points being made.
Findings
The paper argues that the key elements of a plumbed‐in performance management system are: performance architecture; performance insights; performance focus; and performance action. Taken together, these four elements provide the necessary plumbing to enable performance management systems to deliver real value.
Research limitations/implications
The paper draws on the experience of the authors, rather than a formally designed piece of research. The ideas presented in the paper would therefore benefit from further investigation and testing.
Originality/value
The paper will be valuable to scholars and practitioners interested in ensuring that performance management systems deliver lasting value.
Details