8th International Conference on Power Electronics and Variable Speed Drives
Buy conference proceeding
- Location: London, UK
- Conference date: 18-19 Sept. 2000
- ISBN: 0 85296 729 2
- Conference number: CP475
- The following topics were dealt with: power electronics; variable speed drives; active power filters; AC-AC power convertors; HF power convertors; renewable energy; induction motor drives; electric machines; power semiconductor devices; field oriented control; sensorless control; power factor correction; brushless motor drives; reluctance motor drives; DC-DC power convertors; power quality; industrial power convertors; and power convertor simulation
1 - 20 of 99 items found
-
The future of electric drives: where are we headed?
- Author(s): R.D. Lorenz
- + Show details - Hide details
-
p.
(5)
A key dimension for the future of motor drives is to make them reliable, value-added parts of a system. Reliability of motor drives is far from a resolved issue. The failure of drives has been attributed to many causes, but one of the dominant ones is “misuse” in the application. While this may not seem like a drives problem, it actually represents one of our biggest opportunities for value-added engineering of drives. In essence, future drives need to be designed to live and function despite ongoing abuse. This may seem trivial, but the resolution of such application specific problems has vexed even the best of drive suppliers. This research domain is not simply another application of neural networks or fuzzy logic. Instead it will rely on smart drive research engineers who develop drives such that they avoid operating conditions which are not compatible with sustained operation and continue doing their main function, despite their lack of full knowledge of the load. This paper begins to unfold a vision of this future set of challenges.
-
Test and characterisation of modern fast recovery diodes for high speed switching applications
- Author(s): M.T. Rahimo and N.Y.A. Shammas
- + Show details - Hide details
-
p.
(5)
In modern power electronics applications, diodes and other circuit components have been required to switch at much higher speeds and frequencies. Ultra fast recovery diodes complementing modern high power switching devices such as IGBTs and MOSFETs are available with extremely small switching parameters. Characterisation of such devices requires a good understanding of the device requirements, improved electrical test circuits and special test procedures. In this paper, the main requirements for the test and characterisation of modern ultra fast power diodes are discussed. A brief description of different test circuits traditionally used to carry out the dynamic tests are presented outlining the advantages and disadvantages of each method. In addition, the authors suggests improved methods for testing modern ultra fast diodes especially for high speed switching applications. Results for the diode reverse recovery waveforms obtained using different test circuits are also presented.
-
Operation of system double fed machine-turbine in power network
- Author(s): I. Schreier ; M. Chomat ; J. Bendl
- + Show details - Hide details
-
p.
(4)
The paper deals with analysis of the operation of the system composed of a doubly fed machine and a water turbine connected to the power network with constant voltage. The interaction of vector control of the electrical machine with a cycloconverter in the rotor circuit and control of the turbine at optimal speed is studied.
-
A fuzzy logic controlled power electronic system for variable speed wind energy conversion systems
- Author(s): Z. Chen ; S.A. Gomez ; M. McCormick
- + Show details - Hide details
-
p.
(5)
An intelligent power electronic system based on a fuzzy logic controller is presented for variable speed wind power conversion systems. The proposed scheme uses a fuzzy logic approach to control the electromagnetic torque for maximum power capture and dynamic performance improvement of the turbine-generator system. The system does not require the information on the wind velocity and can effectively limit electrical power fluctuations. Simulation results have demonstrated the effectiveness of the proposed method.
-
Design and construction of a modular electronic photo-voltaic simulator
- Author(s): S.H. Lloyd ; G.A. Smith ; D.G. Infield
- + Show details - Hide details
-
p.
(3)
The design and construction of a modular electronic photovoltaic (PV) simulator is presented. This is to be used to develop a reliable and repeatable methodology for the assessment of maximum power point tracking (MPPT) performance. As part of the design process the simulator was modelled using Ispice and Simulink. A linearised model was derived which is used to obtain an optimal compromise between accuracy and dynamic performance for the controller.
-
Real-time maximum power point tracking for grid-connected photovoltaic systems
- Author(s): L. Zhang ; A. Al-Amoudi ; Yunfei Bai
- + Show details - Hide details
-
p.
(5)
The paper presents a model-based method for photovoltaic array maximum power point prediction. The method was tested successfully on a small grid-connected PV system. A three-phase IGBT-voltage-source inverter is used as the power conditioner and a DSP-controller is employed to perform real-time control and prediction functions. The system and experimental results obtained are presented in the paper.
-
Current control of active power filters assisted by adaptive algorithm
- Author(s): S. Fukuda and H. Kamiya
- + Show details - Hide details
-
p.
(4)
An active power filter is required to have a high current control capability of tracking a time-varying current reference template. However, a steady-state current error always exists because the reference current varies in time. This paper proposes the application of adaptive digital signal processing to the current control of an active filter. It does not require any additional hardware, but it can automatically minimize the steady-state current error. Experimental results demonstrate the usefulness of the adaptive digital signal processing algorithm for improving the filter performance.
-
Maximum power point tracking with capacitor identificator for photovoltaic power system
- Author(s): N. Kasa ; T. Iida ; H. Iwamoto
- + Show details - Hide details
-
p.
(5)
This paper presents a perturbation and observation method with an identifier of capacitor for the maximum power point tracking (MPPT) in a photovoltaic power system. Usually, by increasing or decreasing the duty ratio of on-state of switching device, the maximum power point is tracked. The variation of duty ratio is determined by considering its circuit parameters. However, it is known that actual capacitance of an electrolytic capacitor in parallel with the photovoltaic array has 50% error of its nominal value. If the variation of duty ratio is determined based on its nominal value, the performance of MPPT is degraded. Thus, accordingly we must change the variation of duty ratio based on its actual value. In our system, we adapt the model reference adaptive system to identify the capacitor, then we can estimate the accurate capacitance and correct the variation of duty ratio. As a result, we may obtain the high performance of MPPT. Experimental results are shown using a proposed power inverter using buck-boost chopper circuits.
-
110 W low cost, efficient PV-grid interface for rural electrification
- Author(s): M.N. Mather ; M. Malengret ; J.C. Le Claire
- + Show details - Hide details
-
p.
(3)
PV-utility interface systems for remote rural South Africa are investigated: contemporary topologies are assessed and a unique concept formulated. Based on this, a low power 110 W prototype unit was developed using a highly integrated, low-cost microcontroller. The PV-panel attaches (via a DC-bus capacitor filter) to an H-Bridge. The H-bridge pulse width modulates the DC bus to create a high quality low voltage sine-wave (after an LC filter). The sine-wave is then stepped up to the utility voltage by a standard 50 Hz mains transformer. Preliminary experimental results are included.
-
A method of iron loss and magnetising flux saturation modelling in stationary frame reference of single and two-phase induction machines
- Author(s): M. Popescu and V. Navrapescu
- + Show details - Hide details
-
p.
(6)
This paper proposes an equivalent circuit for the single and two-phase induction machines including simultaneously, but as independent phenomena, the iron loss and the main flux saturation. This model permits an improvement in operation of vector-controlled single and two-phase induction machines. The vector control structure suitable for the unsymmetrical two-phase induction machine can be either rotor or stator flux oriented control. The model can be implemented for simulations by using either experimentally determined parameters or FEM calculated parameters. The stator field oriented system can be readily implemented on the same DSP board with the rotor field control version, as the same parameters are used. It is expected that the stator flux control should be more suitable for low speed applications, while the rotor flux control system is useful for high-speed applications.
-
Improved direct and inverse gamma models for vector controlled induction machines
- Author(s): M. Popescu
- + Show details - Hide details
-
p.
(6)
This paper analyses equivalent circuit models for vector controlled induction motor for dynamic and steady-state operation analysis, that accounts for stator saturation and core loss effects. The circuits, denoted as Γ or inverse-Γ model, are simpler than the conventional third order T-model of equivalent circuit. Their parameters are readily obtained from no-load and standstill measurements. Using the derived models, it is shown that the unwanted cross coupling introduced by saturation and core loss can be eliminated in order to obtain de-coupled flux and torque control. Compensation of stator saturation and iron loss may be realised through modified stator or rotor flux oriented controller. Although more complex than the standard ones, these controllers are easily implemented by DSP technologies. The additional required data is the saturation characteristics (air-gap flux vs. magnetisation current) for determining the nonlinear inductance that models the saturation and the value of the equivalent iron loss resistance.
-
PSpice model for asymmetrical two-phase induction motors
- Author(s): D. Vanata and J.M. Marti
- + Show details - Hide details
-
p.
(3)
Simulation models for two-phase induction motors are often based on the reference frame theory and utilise mathematical programs to solve the differential equations and compute stator currents. In general these models lack the capability of incorporating nonlinear semiconductor behaviour for power electronic circuits. In this article a PSpice simulation model for an asymmetrical two-phase induction motor is proposed to model the motor with semiconductor based power converter circuits. A model validation is performed and simulation results are shown.
-
Application of Rosenbrock algorithm to motor parameters identification using transient stator current measurements
- Author(s): M. Bounekhla ; M.E. Zaim ; A. Rezzoug ; M. Ait-Ahmed
- + Show details - Hide details
-
p.
(4)
This work presents a parametric identification using the least square method based on the output error. The Rosenbrock algorithm is applied as a technique to minimise the objective function in order to obtain simultaneously the electrical and the mechanical machine parameters. The validation of the algorithm is obtained from experiments carried out on different machines.
-
An adaptive rotor flux observer with time varying gain for direct field oriented induction motor drives
- Author(s): A. Damiano ; G. Gatto ; I. Marongiu ; M. Scano
- + Show details - Hide details
-
p.
(6)
At the present time the direct field oriented (DFO) control is the widespread used control technique in high performance induction motor (IM) drive. As it is well known, the IM drive performances are strictly connected to the rotor flux observation. The motor parameter variations cause the observer de-tuning and, hence, the IM drive performance degradation. In the present paper an adaptive observer is proposed which allows the on-line rotor time constant tuning. The identification of the rotor time constant is performed by a MRAS approach. The adaptive observer is synthesised using the Lyapunov stability theory. To improve the speed convergence of the identifier and the selectivity characteristic of the proposed adaptive observer, a time varying gain has been introduced. Simulations conducted on a DFO controlled drive, are reported to evidence the good performance of the proposed observer.
-
An observer-based DTC of induction motors driven by 3-level inverter for improving low speed operation
- Author(s): K.B. Lee ; J.H. Song ; I. Choy ; J.Y. Choi
- + Show details - Hide details
-
p.
(5)
Direct torque control algorithm for 3-level inverter-fed induction motors is proposed. Conventional selection method of the stator voltage vector shows problems of stator flux drooping phenomenon and undesirable torque control appeared especially at the low speed operation. To overcome these problems, a proposed method uses intermediate voltage vectors, which are inherently generated in 3-level inverters. An adaptive observer is also employed to estimate some state-variables and motor parameters, which takes a deep effect on the performance of the low speed operation. Simulation and experiment results verify effectiveness of the proposed algorithm.
-
Optimum-seeking field weakening control of induction motor drives
- Author(s): L. Harnefors ; K. Pietilainen ; L. Gertmar
- + Show details - Hide details
-
p.
(5)
The optimum-seeking (in the sense of maximisation of torque) field weakening control scheme proposed by Kim and Sul (see IEEE Trans. Ind. Electron., vol. 44, no.4, p.512-18, 1997) is developed further. The performance under imperfect field orientation conditions is investigated, and it is shown that an overestimated-rather than an under-estimated-model leakage inductance should be used. A slightly modified algorithm, which offers better robustness and reduced computational complexity, is presented. The importance, for good performance, of combining the scheme with a current controller featuring anti-windup and improved disturbance rejection is emphasized. The dynamics of the resulting closed-loop system are analysed. Thus obtained are rules for selection of all controller parameters, allowing for straightforward implementation and commissioning. Good performance of the resulting system is verified experimentally.
-
Predictive control of active power filters
- Author(s): J.H. Marks and T.C. Green
- + Show details - Hide details
-
p.
(5)
A novel technique for delayless calculation of the fundamental component of the input current for a three-phase rectifier, with an inductive smoothing filter, is presented. The technique provides a means to accurately estimate the necessary cancellation current reference for use in an active power filter (APF) under transient conditions. An artificial neural network (ANN) based predictor directly calculates the mean DQ-axis currents without filtering. The technique is applied to experimental data and compared against conventional cancellation reference calculation techniques.
-
Current fed induction machine
- Author(s): J.F. Yhuel ; S. Siala ; J.C. Le Claire
- + Show details - Hide details
-
p.
(5)
In this paper, the authors present an induction motor drive vector control strategy involving a current regulated voltage source inverter (CRVSI). Instead of using a classical PWM, we employ a novel analog modulator which allows the current control in inductive loads. To check this control method, the authors compare its performances with the direct torque control (DTC), which provides very fast dynamics. By the use of both of these control methods, simulated results demonstrate the excellent torque dynamic.
-
Low cost technique for sensorless vector control of induction motors robust in the presence of variations of resistive parameters
- Author(s): F. Vargas-Merino ; J. Fernandez-Moreno ; F.M. Perez-Hidalgo ; J.L. Duran-Paz
- + Show details - Hide details
-
p.
(5)
The work shows a speed control technique for induction motors using vector control, that is characterized by constructive simplicity, good dynamical behaviour and low implementation cost. This technique does not use a speed sensor and results are robust when resistive parameters change. The technique proposed has been developed with SIMULINK/Matlab and experimentally implemented with help of a digital signs processor (DSP).
-
Performance comparison of the controller configurations for the sensorless IM drive using the modified speed adaptive observer
- Author(s): F. Yusivar ; H. Haratsu ; T. Kihara ; S. Wakao ; T. Onuki
- + Show details - Hide details
-
p.
(6)
This paper evaluates the controller configurations for the application of the modified observer introduced in our previous paper (see IEEE 15th Annual Applied Power Electronics Conference, p.127-32, 2000). A full load disturbance is applied to each configuration to observe the load effect. A simple speed estimation adjustment procedure to minimize the speed estimation error at the desired speed is proposed. All results are carried out through experiments.
