Torque control strategy for an axial flux switched reluctance machine

This paper reflects the work done to design a torque control strategy for an axial flux switched reluctance machine. The general electrical model is first presented but as the switched reluctance machine behaves nonlinearly1 a (three-dimensional) finite element method characterization is performed, so the nonlinearity may be considered. Once the machine is characterized in FEM a Simulink model is developed where a torque control strategy is proposed. Then, both the machine and the control are experimentally tested. The control setting, and the obtained real performance results are also presented in this document. Finally, the most outstanding conclusions about the control strategy are captured. Main difficulties encountered during the implementation of the control strategy are also collected

Dynamic measurement of magnetic characteristics of switched reluctance motor

Introduction. Switched reluctance motor (SRM) is a type of electric motor featuring nonlinear magnetic characteristics. The flux linkage or inductance profile of SRM is usually required for the purpose of high control performance, and can be normally obtained through conventional static test by using DC or AC method when the rotor is locked. Problem. However, it is not practical to use the conventional method of measurement when the specific apparatus for locking the rotor is unavailable. Besides, due to the magnetic nonlinearity of SRM, the saturation effect makes it difficult to obtain the saturated magnetic characteristics, and the conventional static AC test fails to address this problem. Novelty. In this paper, a dynamic measurement method of the magnetization curves of SRM is proposed which allows the measurement take place while the motor is running with load. Methodology. Based on the conventional static AC test, the proposed measurement handles the saturation problem successfully by introducing a DC offset in the high frequency AC voltage. Phase inductance with different rotor positions and currents can be obtained by analyzing simple equivalent circuit. Practical value. Simulation is conducted in MATLAB/Simulink environment and the results have verified that the proposed dynamic measurement can effectively obtain the magnetic characteristics of SRM.Вступ. Вентильний реактивний двигун (ВРД) є типом електродвигуна з нелінійними магнітними характеристиками. Профіль потокозчеплення або індуктивності ВРД зазвичай потрібний для забезпечення високої ефективності управління і зазвичай може бути отриманий за допомогою звичайних статичних випробувань з використанням постійного або змінного струму, коли ротор заблокований. Проблема. Однак недоцільно використовувати традиційний метод вимірювання, коли відсутній спеціальний пристрій для блокування ротора. Крім того, через магнітну нелінійність ВРД ефект насичення ускладнює отримання насичених магнітних характеристик, і звичайне статичне випробування змінним струмом не вирішує цю проблему. Новизна. У цій роботі пропонується метод динамічного вимірювання кривих намагнічування ВРМ, який дозволяє проводити вимірювання під час роботи двигуна з навантаженням. Методологія Пропонований вимір, заснований на звичайному статичному випробуванні змінним струмом, успішно вирішує проблему насичення за рахунок введення зміщення постійного струму у високочастотну змінну напругу. Фазна індуктивність при різних положеннях ротора та струмів може бути отримана шляхом аналізу простої еквівалентної схеми. Практична цінність. Моделювання проводилося у MATLAB/Simulink, і результати підтвердили, що пропонованим динамічним вимірюванням можливо ефективно отримати магнітні характеристики ВРД

Dynamic measurement of magnetic characteristics of switched reluctance motor

Introduction. Switched reluctance motor (SRM) is a type of electric motor featuring nonlinear magnetic characteristics. The flux linkage or inductance profile of SRM is usually required for the purpose of high control performance, and can be normally obtained through conventional static test by using DC or AC method when the rotor is locked. Problem. However, it is not practical to use the conventional method of measurement when the specific apparatus for locking the rotor is unavailable. Besides, due to the magnetic nonlinearity of SRM, the saturation effect makes it difficult to obtain the saturated magnetic characteristics, and the conventional static AC test fails to address this problem. Novelty. In this paper, a dynamic measurement method of the magnetization curves of SRM is proposed which allows the measurement take place while the motor is running with load. Methodology. Based on the conventional static AC test, the proposed measurement handles the saturation problem successfully by introducing a DC offset in the high frequency AC voltage. Phase inductance with different rotor positions and currents can be obtained by analyzing simple equivalent circuit. Practical value. Simulation is conducted in MATLAB/Simulink environment and the results have verified that the proposed dynamic measurement can effectively obtain the magnetic characteristics of SRM.Вступ. Вентильний реактивний двигун (ВРД) є типом електродвигуна з нелінійними магнітними характеристиками. Профіль потокозчеплення або індуктивності ВРД зазвичай потрібний для забезпечення високої ефективності управління і зазвичай може бути отриманий за допомогою звичайних статичних випробувань з використанням постійного або змінного струму, коли ротор заблокований. Проблема. Однак недоцільно використовувати традиційний метод вимірювання, коли відсутній спеціальний пристрій для блокування ротора. Крім того, через магнітну нелінійність ВРД ефект насичення ускладнює отримання насичених магнітних характеристик, і звичайне статичне випробування змінним струмом не вирішує цю проблему. Новизна. У цій роботі пропонується метод динамічного вимірювання кривих намагнічування ВРМ, який дозволяє проводити вимірювання під час роботи двигуна з навантаженням. Методологія Пропонований вимір, заснований на звичайному статичному випробуванні змінним струмом, успішно вирішує проблему насичення за рахунок введення зміщення постійного струму у високочастотну змінну напругу. Фазна індуктивність при різних положеннях ротора та струмів може бути отримана шляхом аналізу простої еквівалентної схеми. Практична цінність. Моделювання проводилося у MATLAB/Simulink, і результати підтвердили, що пропонованим динамічним вимірюванням можливо ефективно отримати магнітні характеристики ВРД

Numerical estimation of switched reluctance motor excitation parameters based on a simplified structure average torque control strategy for electric vehicles

Switched reluctance motors (SRMs) have been receiving great attention in electric vehicle (EV) applications. However, the complicated control and inherent torque ripples are the major drawbacks of SRMs. This paper introduces a numerical estimation method for the optimum control parameters of SRM based on a simplified average torque control (ATC) strategy for EVs. The proposed control aims to simplify the control algorithm to cut down complexity and cost. Besides, it aims to achieve all the vehicle requirements. A multi-objective optimization problem is set to determine the most efficient excitation parameters that can fulfill the vehicle requirements. The objective function has two terms: torque ripple and efficiency. Proper constraints for both turn-on and turn-off angles are included in order to achieve high-performance control, maximum torque per Ampere (MTPA) production, and reliable operation. Besides, additional toque constraints are involved to ensure fast dynamics, high-performance torque tracking capability, and parameter insensitivity. The motor model is accurately achieved based on the experimentally measured torque and flux characteristics. Several simulations are executed to prove the feasibility and effectiveness of the proposed control. Moreover, experimental results are obtained to validate the theoretical findings. It is observed that the proposed control has a significant reduction of torque ripples compared to the conventional control methods. The average reduction ratio of torque ripple over the speed range is about 72.43%. Besides, the proposed control succeeds in maintaining a very good efficiency and high torque/current ratio. It also has a fast-dynamic performanc

Modelling and Control of Switched Reluctance Machines

Today, switched reluctance machines (SRMs) play an increasingly important role in various sectors due to advantages such as robustness, simplicity of construction, low cost, insensitivity to high temperatures, and high fault tolerance. They are frequently used in fields such as aeronautics, electric and hybrid vehicles, and wind power generation. This book is a comprehensive resource on the design, modeling, and control of SRMs with methods that demonstrate their good performance as motors and generators

Modelling and Control of Switched Reluctance Machines

Today, switched reluctance machines (SRMs) play an increasingly important role in various sectors due to advantages such as robustness, simplicity of construction, low cost, insensitivity to high temperatures, and high fault tolerance. They are frequently used in fields such as aeronautics, electric and hybrid vehicles, and wind power generation. This book is a comprehensive resource on the design, modeling, and control of SRMs with methods that demonstrate their good performance as motors and generators

Online magnetization surface identification for a switched reluctance motor

The precise control of switched reluctance motor requires information about the magnetization surface as a function of rotor angular position and current. The surface can be obtained performing offline tests; however, it demands specialized mechanical equipment and time for commissioning. Moreover, the magnetization surface may be changed with the varying of the rotor and stator temperatures, which affect their dimensions and, therefore, the airgap variation. That is why the online estimation of the magnetization surface is desirable. This paper proposes the identification method operating in parallel with the model predictive current control system utilizing the magnetization map. Any error between the referenced and obtained currents is used to correct the reference points of the two-dimensional array representing the magnetization surface. The proposed method was examined using a simulation model and operated online in parallel with the primary control system driving the electrical machine

Analysis of consequent-pole flux reversal permanent magnet machine with biased flux modulation theory

This paper investigates a consequent-pole flux reversal machine (CP-FRM) with biased flux modulation theory, which employs homopolar permanent magnets (PMs) placed between the adjacent stator poles. The machine topology is introduced from the perspective of FRM with a shifted magnet position and CP arrangement, and the performance comparison between the proposed CP-FRM and its original surface-mounted PM (SPM) counterpart is presented to highlight the torque improvement of the CP structure. Then, a simplified permeance model is applied to the CP-FRM to identify the principal effective air-gap field harmonics engaging in the torque productions. It shows that the CP-FPM works based on a biased flux modulation effect due to its asymmetric air-gap field distribution caused by the CP configuration, which unveils its underlying torque improvement mechanism over its SPM-FRM counterpart. In order to obtain the highest torque capability, the key design parameters are analytically optimized by analyzing the winding configuration, which aids the establishment of a general design guideline for the CP-FRM. The analytical and FE results are validated by the experiments

Development of methods, algorithms and software for optimal design of switched reluctance drives

The aim of this thesis is to estimate the perspectives of integrated switched reluctance drives (I-SRDs), i.e. reluctance machines integrated with converters. It is assumed that such drive series can be manufactured in the power range of 0.75...7.5 kW and speed ranges of 300...3000 rpm and 600...6000 rpm for applications like pumps, fans, conveyors, compressors, extruders and mixers. Based on the performed research and design work it is stated that the new drives have to be developed according to their applications, which determine objective functions and constraints, and that the best possible design should be found as a solution of a synthesis task. Sizing equations are not applied at all. The approach used in the thesis is based on the virtual prototyping concept, i.e. the new I-SRD series is designed in a virtual environment. Therefore, mathematical models and the ways to verify them have to be elaborated. The concepts of multidisciplinary and multilevel modeling are applied. The multidisciplinary model is a combination of interconnected electromagnetic, thermal and noise models. The multilevel concept is the approach when different elements of the drive are described using different languages, i.e. on different levels. Several original solutions are introduced, like the electromagnetic model comprising SIMULINK block-diagrams and MATLAB script, expressions for the correction of the flux linkage due to end-effects, an original equivalent circuit for thermal analysis, which allows using a very simple and fast method to solve the circuit, together with the concept of a multi-layer equivalent cylinder for modeling the motor winding. For verification of the multidisciplinary model a database of test results has been collected using both testing of several reluctance machines in the laboratory and analyzing of test results published by other researchers. After verification the model can be considered as a virtual prototype and can be used in the synthesis process. Several methods of solving the synthesis task were tested. The method, proved to be best suited for solving this task in the proposed form, is the genetic algorithm in the vector form with alphabetic encoding. The genetic algorithm should be coupled with the experimental design method or with the Monte-Carlo method