Switched Reluctance Motor System Research Articles

A Lambert importance model‐based reliability design method for power converters in switched reluctance motor systems

SummaryThe reliability of power converters is crucial for achieving high‐performance operation in switched reluctance motor (SRM) systems. However, there is a notable deficiency in reliability‐oriented design of power converters that can effectively integrate both static and dynamic reliability indicators. To address this issue, this paper proposes a reliability design methodology for power converters based on the Lambert importance model, aimed at enhancing reliability of SRM systems. Firstly, the modeling principles of Lambert importance model are presented. Subsequently, a reliability design method is proposed to maximize reliability within a unit economic cost framework. Especially, the proposed design scheme is designed to maximize reliability enhancement potential through a two‐pronged approach: strategic topology selection informed by potential reliability assessments and component selection guided by importance calculations. Meanwhile, dynamic reliability evaluation is carried out to form a double‐loop reliability feedback and increase the credibility of design scheme. Finally, an example is developed to verify the validity of proposed reliability design scheme.

Quantized iterative learning control for impulsive differential inclusion systems with data dropouts

This paper studies the quantized iterative learning control with encoding–decoding mechanism of a class of impulsive differential inclusion systems with random data dropouts. First, the set-valued mappings in the differential inclusion systems are transformed into single-valued mappings by using the Steiner-type selector. Then, a learning algorithm based on the intermittent update principle is designed to address the data asynchronism problem caused by two-sided data dropouts. If the data are successfully transmitted at the actuator and measurement sides, then the control input is effectively updated. Furthermore, a suitable scaling sequence is introduced to ensure the system output to achieve zero-error tracking performance for a desired trajectory. An upper bound of the quantization level is determined such that the quantization error is always bounded. The results show that the quantization method reduces the burden of network communication at the cost of increasing the amount of computation, and the learning algorithm does not require the data dropouts to satisfy a certain probability distribution. Finally, the effectiveness of the learning algorithm is verified by numerical simulations of the switched reluctance motor system.

A Novel-Driven Scheme Regarding to Current Dynamics Enhancement for Switched Reluctance Motor System

Aiming at lowering the cost and enhancing the current dynamics for switched reluctance motor (SRM) system, a novel driven scheme is proposed by combing the self-boost voltage converter (SBVC) and chopping limit active regulation (CLAR) current control strategy. First, the working modes of SBVC are analyzed during the one-phase and two-phase operation situations. And the DC-link voltage pump-up mechanism and capacitor parameters selection method are developed. Then, the CLAR current control strategy is performed to adjust the excitation voltage and demagnetization voltage and then shape the current waveform. Owing to the proposed current profile generation technique, the excitation time and demagnetization time can be actively adjusted to enhance the current dynamics under different mission profiles. Compared to the existing current dynamics enhancement strategy, the proposed operation strategy achieves the lower cost, better current tracking performance, lower torque ripple and wider speed range. Simulations and experiments are performed on a four-phase 8/6 SRM to verify the validity of the proposed operation strategy in different mission profiles.

A Review on Predictive Control Technology for Switched Reluctance Motor System

The significance of employing control strategies on a switched reluctance motor (SRM) is that they can reduce vibration noise and torque ripple. With the rapid development of digital system processors, predictive control (PC), as a modern control approach, is increasingly applied to enhance the dynamic performance and operational efficiency of SRMs. This review provides a comprehensive overview of the current state of research on PC strategies of SRMs and classifies PC technologies, such as generalized predictive control (GPC), hysteresis predictive control (HPC), deadbeat predictive control (DPC), and model predictive control (MPC). It summarizes the PC schemes from the aspects of predictive current control (PCC), predictive torque control (PTC), and other PC, and it discusses the current trends in technology development, as well as potential research directions. The insights presented herein aim to facilitate further investigations into predictive control techniques for SRM.

Direct Instantaneous Torque Control of SRM Based on a Novel Multilevel Converter for Low Torque Ripple

The torque ripple of a switched reluctance motor (SRM) limits its application in electric vehicles. This paper proposes a DITC system for SRMs based on a novel multilevel converter (MLC), which aims at the problem that the torque ripple cannot be effectively suppressed for the conventional direct instantaneous torque control (DITC) of an SRM due to the limitation of the DC bus voltage in the asymmetric half-bridge converter (AHBC) and the single control strategy formulated in the commutation region. Based on the advantages of fast excitation and fast demagnetization for the proposed MLC and the torque distribution characteristics for each phase winding in the commutation region, a novel torque hysteresis control strategy is developed to improve the torque-following ability of the DITC and achieve the purpose of minimizing the torque ripple in the commutation region. In addition, multiobjective optimization control of the motor is carried out to improve the efficiency of the DITC system while suppressing the torque ripple. The effectiveness of the proposed SRM drive scheme is verified by experiment, which is of great significance for the application of SRMs in electric vehicles.

Fault diagnosis and fault‐tolerant control of uncertain network control systems

SummaryIn this article, the equivalent control strategy based on Laplace transform is proposed for the problem of stochastic delay in networked control systems. The original system is transformed into an equivalent control system without random delay block by Laplace transform. Then, a new augmented variable and equivalent control system is introduced to construct an augmented system. An adaptive fault diagnosis observer is designed based on the augmented system. The adaptive turning rate of the observer is obtained by solving the corresponding linear matrix inequality. Based on the information of online fault diagnosis and state estimation, a fault‐tolerant controller based on PI control strategy is designed to compensate the fault. Finally, a model of the switched reluctance motor system is considered to show the effectiveness of this method.

A Simple Method to Control The Excitation Angle for Switched Reluctance Motor

A switched reluctance motor (SRM) has been an alternative solution for electric drives because of its benefit features. The use of such a motor in electric vehicles (EVs) or hybrid electric vehicles (HEVs) requires a control strategy that is capable to develop high torque. SRMs are commonly available in the market with rotor position detectors embedded inside. Problems will appear when such detectors are not symmetrically installed because most of SRM control strategies are commonly based on them. Inaccurate pulses will be generated by the control circuit which finally takes effect on phase current commutation or the beginning of the excitation which is not on proper angle. The use of such detectors is just capable to give information of rotor position in common angles. Improvement for such problems can be done by generating pulses related to the rotor position in smooth angles. In this paper, a control strategy to produce excitation signals with proper angles for SRM stator winding is proposed. By using input capture facility that is commonly available in embedded system, excitation angles can be controlled precisely because a large number of pulses can be produced by the system. Accuracy level of this strategy is determined by TIMER period of embedded system and speed of SRM. To verify the analysis, laboratory experiments were done. They show that the proposed control strategy is capable to rotate the motor with better performance.

Gravity measurement method of solid rocket drive based on switched reluctance motor system

Solid rocket drive system based on switched reluctance motor is established through the working principle of switched reluctance motor, and the closed-loop precise control of solid rocket drive system digitization is realized by the control method of pulse width modulation technology. The gravity value of solid rocket drive system is measured by the vertical deviation measurement method based on attitude error observation. The attitude datum of solid rocket drive system is obtained by the relationship between the vertical deviation and the attitude error of solid rocket drive system. The state space of solid rocket drive system is established by the attitude datum obtained. The horizontal gravity component estimation model of the real gravity value of the solid rocket drive system is established by the state space model, and the accurate gravity value of the solid rocket drive system is obtained by the estimation model. The simulation results show that the method can effectively measure the gravity value of solid rocket driving system, and the errors of measuring the gravity of solid rocket driving system are less than 1%.

MFO-ANN based FOPID Controller for Torque and Speed Control of SRM Drive System

This paper proposed an optimal control algorithm based Fractional Order PID (FOPID) controller for the torque ripple minimization of Switched Reluctance Motor (SRM) drive system. That convalesce both control loop task, the Moth Flame Optimization (MFO)- Artificial Neural Network (ANN) algorithm is insinuated. The routine of intelligent technique is principally as the objective function of system error minimization. At this time the quality inspired algorithm of MFO is firstly reconnoitered to optimize the speed and torque error from the SRM system. Instead the output of MFO algorithm is optimized and to finding the premium value, the ANN method is recuperated. Nonetheless, the output of MFO-ANN is imperiled to the input of FOPID controller. For tweaking the exact FOPID gains, the multi objective functions are grew. Created on the operation of propositioned algorithm by normalize the system speed and minimalize the torque ripples of SRM system. The qualities of the suggested procedure are force falconer and in addition to augmented level of the reliability and flexibility in answering the system error. Also the enactment of proposed MFO-ANN process is executed in the MATLAB/Simulink running platform.

Reliability Evaluation for Power Converter of SRM on Fault-Tolerance Capability and Thermal Stress

In this article, a novel reliability evaluation scheme to achieve quantitative reliability calculation for power converter in the whole operation region of switched reluctance motor system is proposed. First, the electrical model is built to obtain electrical stress and fault-tolerance capability in the Matlab/Simulink environment. Second, the thermal circuit model is performed to get the thermal stress of power converter quickly. Third, the dynamical Markov model with a novel failure criterion is applied to achieve quantitative reliability calculation by characterizing the fault-tolerance capability and thermal stress. The proposed failure criterion can simplify the model to decrease the number of states and avoid the divergence of results, especially the interconnected relationship between the three models is key emphasized. Next, the proposed reliability evaluation scheme is carried out to explore the reliability of power converter under different chopping modes. Finally, simulations in conjunction with experiment verify the validity of the proposed reliability evaluation scheme.

Output Delay Sliding Mode Tracking Control of SRM based on Multi-innovation Model Identification

The drive system of switched reluctance motor (SRM) is a complex nonlinear system that is composed of many links. The delay in the measurement of the speed and position signal of SRM is caused by the factors that affect the measuring sensor. To effectively improve the influence of the SRM rotor position and speed signal delay on the system performance, a sliding mode position tracking method based on output delay observation was proposed in this study. First, the model was discretized according to the structure and characteristics of SRM and the mathematical parameters of the system were identified using a multi-innovation stochastic gradient (MISG) algorithm. Second, a delay state observer was constructed on the basis of an SRM system model with output delay. Then, the sliding mode tracking control method based on the delay state observation compensation was proposed and combined with sliding mode control theory. Lastly, the effectiveness of the designed model parameter identification, delay state observation, and output delay control methods were compared through numerical simulation. Results show that when uncertain factors, such as noise, are present in the system, the MISG identification method can rapidly and accurately identify the parameters of the SRM model compared with the stochastic gradient identification method; the identification accuracy of the former is four times higher than that of the latter. Similarly, the sliding mode position tracking control method based on output delay observer can rapidly and accurately track the position and speed within 0.5 s. However, its position (0.2 rad) and velocity (0.233 rad/s) tracking exhibit large steady-state errors when no delay observation compensation is present. The proposed method not only demonstrates high position tracking accuracy, but also possesses strong robustness to output delay.

Design and Analysis of a Novel Converter Topology for Photovoltaic Pumps Based on Switched Reluctance Motor

In order to improve the performance of switched reluctance motor (SRM) systems for photovoltaic (PV) pumps, this paper introduces a new converter topology for SRM with controllable multiple power sources. Only simple switching components need to be added at the front end of the asymmetric half-bridge converter in this topology, which enables the control of multiple power sources. The new PV pump system has four operating modes, which are the PV panel driven mode, battery bank driven mode, dual-source driven mode, and battery charging mode. By adjusting the state of the front-end converter switch, the voltage tracking of PV panel can be achieved, providing a stable bus voltage for the SRM system. By controlling the battery bypass switch, the bus voltage of SRM system can be increased, thereby increasing the system power level. Simulations and experiments based on a four-phase 8/6 SRM demonstrate the effect of the novel converter proposed in this paper.

One‐cycle decoupling control method of multi‐leg switching power amplifier for magnetic bearing system

The traditional current control algorithm of the multi-leg switching power amplifier (SPA) is complicated since the control of different phase currents is intercoupling. To address this problem, a novel control strategy based on one-cycle control is proposed in this study, which can enforce the average current of each phase is equal to the reference in each control cycle. Since it sets the duty cycle of the neutral leg as a constant, this method presents significant advantages such as quick dynamic response, easy control and decoupling of the phase currents. Taking a five-phase six-leg SPA, e.g. the mathematic model of the system was built, the duty cycle of the neutral leg was analysed, the principle of the novel control strategy was introduced, and the detailed implemented process was presented. Thereby, a high-speed switched reluctance motor system using the magnetic bearing is constructed to test this method. Both the simulation and experimental results have demonstrated the simplicity and effectiveness of the proposed method.

Electromagnetic field analysis and cooling system design for high power switched reluctance motor

PurposeThe electromagnetic field and cooling system of a high power switched reluctance motor (SRM) are studied numerically. The geometry of the motor and its main components are established using a computer-aided design software in the actual size. This study aims to evaluate the resulting thermal losses using the electromagnetic analysis of the motor.Design/methodology/approachIn the electromagnetic analysis, the Joule’s loss in the copper wires of the coil windings and the iron losses (the eddy currents loss and the hysteresis loss) are considered. The flow and heat transfer model for the thermal analysis of the motor including the conduction in solid parts and convection in the fluid part is introduced. The magnetic losses are imported into the thermal analysis model in the form of internal heat generation in motor components. Several cooling system approaches were introduced, such as natural convection cooling, natural convection cooling with various types of fins over the motor casing, forced conviction air-cooled cooling system using a mounted fan, casing surface with and without heat sinks, liquid-cooled cooling system using the water in a channel shell and a hybrid air-cooled and liquid-cooled cooling system.FindingsThe results of the electromagnetics analysis show that the low rotational speed of the motor induces higher currents in coil windings, which in turn, it causes higher copper losses in SRM coil windings. For higher rotational speed of SRM, the core loss is higher than the copper loss is in SRM due to the higher frequency. An air-cooled cooling system is used for cooling of SRM. The results reveal when the rotational speed is at 4,000 rpm, the coil loss would be at the maximum value. Therefore, the coil temperature is about 197.9°C, which is higher than the tolerated standard temperature insulation material. Hence, the air-cooled system cannot reduce the temperature to the safe temperature limitation of the motor and guarantee the safe operation of SRM. Thus, a hybrid system of both air-cooled and liquid-cooled cooling system with mounting fins at the outer surface of the casing is proposed. The hybrid system with the liquid flow of Re = 1,500 provides a cooling power capable of safe operation of the motor at 117.2°C, which is adequate for standard insulation material grade E.Originality/valueThe electromagnetic field and cooling system of a high power SRM in the presence of a mounted fan at the rear of the motor are analyzed. The thermal analysis is performed for both of the air-cooled and liquid-cooled cooling systems to meet the cooling demands of the motor for the first time.

Energy Management System in Electric Vehicle with PV Fed SRM System

This project presents the switched reluctance motor (SRM) with hybrid renewable system. Switched Reluctance Motors (SRM) has a wide range of industrial applications because of their advantages over conventional AC/DC Drives. This is due to simple construction, ruggedness and inexpensive manufacturing potential. Various methods have used and applied to control SRM speed generally, the PV-fed EV has a similar structure to the hybrid electrical vehicle, whose internal combustion engine(ICE) is replaced by the hybrid system. A hybrid energy system, or hybrid power, usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply. The PV has different characteristics to ICEs, the maximum power point tracking (MPPT) and solar energy utilization are the unique factors for the PV-fed EVs. This matter is done by applying the proposed system to a multi-objective function including both speed error and torque ripple. This controller is implemented for an 8/6, 4-kW SRM. In this paper to coordinate the PV panel, SRM and battery. Hybrid renewables applied in Energy storage like battery technologies, superconducting magnetic energy, capacitors, compressed air and pumped storage, seems to be an alternative method that the operator of an electrical power grid can use to adapt energy production to energy consumption, both of which can vary randomly over time. The simulation results confirm excellent dynamic performance, reduced torque ripple and current oscillation can be achieved by using ANFIS.

Design and analysis of PV fed SRM system

Renewable energy sources supplied motor applications are being studied widely by researchers. As it is especially focused on design and control of such systems, studies on performance analysis approach is limited. It is vital to determine the operating behaviour of motor loads when they are supplied by limited energy sources like photovoltaic (PV) systems. According to this necessity, in this study, a switched reluctance motor (SRM) which is supplied by a PV system is analysed in terms of speed, current and torque data. Because of its advantages as it can be controlled over a wide range, its reliability and stability, SRM was used for analysis. Such data are observed in two cases, PV system irradiance change and fault conditions. System is designed as direct-fed, which is not include any storage unit. Therefore, any changes at supply system directly affect motor parameters. These effects and results are discussed by using the graphs that obtained from various points of system for both cases.

Circuit‐based flux linkage measurement method with the automated resistance correction for SRM sensorless position control

The accuracy of flux linkage measurement is significantly important for a number of sensorless control methods for switched reluctance motor (SRM). This study proposes a novel flux linkage measurement circuit with the automated resistance correction, which comprises only circuit components. During the SRM sensorless operation, the dependence of resistance on temperature leads to the errors in flux linkage measurement and position estimation. The developed scheme is based on the zero-crossing property which asserts that the flux linkage and current pass through zero simultaneously. Hence, the flux linkage error captured at the time when the current falls to zero represents the resistance error and is used for resistance correction. The proposed circuit has been successfully implemented and tested on a sensorless SRM system. Experiment results indicate that the proposed system in sensorless control can be operated stably at different load torques and at the condition of given speed mutation and load mutation, and the speed range in steady state with rated load torque is 0-160 r/min. The overall estimated position error remains within an acceptable margin of 2%. Hence, it significantly improves the sensorless position estimation and thus SRM performance.

A fault-tolerant control strategy for switched reluctance motor drive for electric vehicles under short-fault condition

This paper proposed a new fault-tolerant control strategy for the short-fault occurring in the switched reluctance motor (SRM) electric drive system, which can not only suppress severe torque ripples in short faults, but also can adjust the total torque and torque ripples in different working conditions to ensure the reliability of the SRM system and the safety of drivers. The proposed strategy is to select the derating states according to the operation requirements when switches short faults occur, then shorten the conduction angle of the faulty phase and adjust the duty cycle of all switches of three phases according to the proposed fault-tolerance rule. Furthermore, the fault-tolerant strategy was applied to a three-phase 12/8 SRM drive. Simulation results in MATLAB/Simulink and experiments on the RT-LAB validate the effectiveness of the proposed strategy, which may be significant in reliability of electric vehicles.

Back‐EMF‐based sensorless control system of hybrid SRM for high‐speed operation

Based on the back electromotive force (back-EMF) detection, a novel rotor position estimation strategy with adjustable turn on/off angle is proposed for the high-speed hybrid switched reluctance motor (SRM). The minimum back-EMF position is captured in every electrical cycle for rotor position estimation. The current comparator is employed to send out a turn-off signal for phase winding when the maximum inductance position is detected in the first electrical cycle. By providing sufficient current rise time to the phase winding, the proposed sensorless control system enables the motor to run in high-speed application. Besides the straightforward estimation principle, the proposed strategy has the implemental feasibility by eliminating extensive calculations and complicated look-up tables. The experimental results of a prototype are demonstrated to verify the proposed sensorless control system.

A Review on Machine Topologies and Control Techniques for Low-Noise Switched Reluctance Motors in Electric Vehicle Applications

This paper presents a technical overview for low-noise switched reluctance motor (SRM) drives in electric vehicle (EV) applications. With ever-increasing concerns over environmental and cost issues associated with permanent magnet machines, there is a technical trend to utilize SRMs in some mass production markets. The SRM is gaining much interest for EVs due to its rare-earth-free characteristic and excellent performance. In spite of many advantages compared with conventional adjustable-speed drives, SRMs suffer from torque ripple and radial distortion (and thus noise and vibration) by their nature. Therefore, for high-performance vehicle applications, it is important and urgent to optimize the SRM system to overcome the drawbacks of the noise and vibration. In order to present clear solutions to the acoustic noise in SRMs, this paper starts by analyzing the mechanism of the radial vibration and torque ripples inherent in the motors, and then focuses on the state-of-the-art technologies to mitigate the radial force and torque ripples. It highlights two categories for low-noise SRMs, including the machine topology improvement and control strategy design for radial vibration mitigation and torque ripple reduction. Advanced technologies are reviewed, classified, and compared accordingly. In addition to these methodologies, the schemes that have been developed by authors are also presented and discussed. Finally, the research status on this topic is summarized and forecast research hotspots are presented. It is our intention that this paper provides the guidance on performance improvements for low-noise SRM drives in EV applications.