Control Of Switched Reluctance Motor Research Articles

Optimized Direct Instantaneous Torque Control for SRMs With Efficiency Improvement

This article proposes an optimized direct instantaneous torque control (DITC) scheme for switched reluctance motor (SRM) drives with a novel adaptive dynamic commutation strategy, which can effectively reduce torque ripple and improve system efficiency. To minimize torque ripple, two operational modes are developed for torque tracking during commutation regions. In Mode I, the torque error is compensated by the outgoing phase during the current buildup region of the incoming phase; in Mode II, the torque error is compensated by the incoming phase during the demagnetization region of the outgoing phase. To implement the proposed DITC scheme in a more effective conduction range, the commutation instants are dynamically adjusted according to the varied operation conditions. For each phase, the turn- on and turn- off angles are modified in each electrical cycle by a torque error regulator and a phase current endpoint detector, respectively. By employing the proposed strategy, the torque generation capability is fully utilized for minimized torque ripple, and the phase currents work within a more effective conduction range for improved system efficiency. The simulation and experiments on a three-phase 12/8 SRM are carried out to verify the feasibility and effectiveness.

Disturbance Observer based Constrained Resonant Control of SRM Integrated EV Drive in Vehicle-to-Home (V2H) Operation

This paper presents a disturbance observer based constrained resonant control strategy for a switched reluctance motor (SRM) integrated electric vehicle (EV) drive in vehicle-to-home (V2H) mode of operation. First, a full-order large-signal model of the integrated drive is developed using averaged modeling technique. Then, a fixed switching frequency disturbance estimation based constrained resonant control with an intrinsic anti-windup mechanism is proposed to achieve a 50Hz sinusoidal voltage at the inverter output. It is shown through simulation studies that the proposed control scheme achieves excellent reference tracking and disturbance rejection with different linear and non-linear load types.

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.

Precise in-situ characterization and cross-validation of the electromagnetic properties of a switched reluctance motor

The electrical-magnetic characteristics of a Switched Reluctance Motor (SRM) exhibit highly nonlinear relationship with respect to the rotor position and excitation current, which poses challenges for both precise static measurements and exact calculation of these properties in real-time control. To guarantee that an in-lab test result can be used in the application, firstly a measurement method is proposed to characterize the SRM's electromagnetic properties such as the flux linkage, magnetic co-energy, phase inductance and electromagnetic torque on the basis of an installed SRM control circuitry and half-bridge power converter. By this means the characterization process is equivalent to the online observation in its results. Secondly, a theoretical model is built to discriminate the physical meaning between the incremental inductance and the phase inductance, which is the origin of other relevant parameters. This helps to guide the correct utilization of the characterization result. Thirdly an in-situ cross-validation experimentation according to the magnetizing and demagnetizing status measurement verifies the feasibilities and accuracy of the proposed inductance measuring method, which avoid a dubious FEM-based comparison between the numerical calculation and experimental results. Cross-validation experiment shows that the proposed in-situ characterization scheme obtains an accurate full-range electromagnetic properties. The proposed methodology breaks the barrier between the in-lab measurement and on-line utilization of the SRM parameters, highlighting the merits that it completely includes the in-situ factors and replicates the operational scenario without the need of specifically designed instrumentation, which is especially suitable for rapid field characterization for high power motors.

Artificial Intelligence Based Vector Controller for Switched Reluctance Motor SRM

The prevalence of the Switched Reluctance Motors (SRMs) increments step by step because of its points of interest, for example, Simple structure, low cost, less weight, high effectiveness and high beginning torque when contrasted with regular motors. SRM is an electric motor which has invaluable highlights that qualifies it to be utilized in electric vehicle, aviation and industrial applications. In this paper, the switched reluctance motor is controlled using vector control by AI controller (fuzzy) so as to limit the torque ripples by directing torque inside indicated hysteresis band. AI Control of SRM encouraged through an irregular converter. The proposed AI controllers are executed in MATLAB/SIMULINK for specified SRM parameters. As indicated by the attained outcomes the SRM behavior is better when impelled by AI controller in contrast with usual controllers.

A Modulation Technique for Sensorless Control of Switched Reluctance Motor

The switched reluctance motor (SRM) uniquely bears several merits with respect to other motor configurations. Especially, the construction of the rotor is simple in the sense that it neither contains copper not contains permanent magnets. Because of this construction, likelihood of rotor’s failure is less than the other motor configurations. This makes this motor more suitable for harsh environments. On the flip side, this motor cannot directly operate with AC or DC power source and needs electronic commutation. For commutation, the information on instantaneous orientation of the rotor is essential. Since inclusion of appropriate sensor adds to the cost and complexity of the system, sensor-less commutation of SRM gained interest among the researchers and has been studied extensively in literature. The techniques for sensorless control of SRM can be broadly classified into Active phase and Idle phase techniques. Idle phase techniques are generally believed to be not suitable for high speed operation beause of tail current in a phase, i.e., because of inductive nature of the phase, it takes time for flow of current to stop. This paper proposes a novel idle phase technique that is conducive for high speed operation of switched reluctance motor.

Synthesis of a fractional-order PIλDμ-controller for a closed system of switched reluctance motor control

The relevance of creating high-quality control systems for electric drives with a switched reluctance motor (SRM) was substantiated. Using methods of mathematical modeling, transient characteristics of the process of turn-on of SRMs with various moments of inertia were obtained. Based on analysis of the obtained transient characteristics, features of the SRM turn-on process determined by dynamic change of parameters of the SRM during its turn-on were shown. Low accuracy of SRM identification using a fractionally rational function of rat34 class was shown. Regression coefficient of the resulting model was 85 %. Based on analysis of transient characteristics of the SRM turn-on process, a hypothesis was put forward about the possibility of identifying the SRM by means of a fractional-order transfer function. Using the methods of mathematical modeling, transient characteristics of the process of turning-on the SRMs with various moments of inertia were obtained. Using the FOMCON MATLAB Toolbox, identification of the SRM turn-on process with the help of a fractional-order transfer function of second order was performed. Regression coefficient of the resulting model was 93–96 %. For the obtained fractional-order transfer functions, a method of synthesis of a fractional-order PI λ D μ controller optimized in terms of minimum integral square error of the transition function of the closed system of fractional-order control of objects was implemented. The FOMCON MATLAB Toolbox was used for synthesis of the PI λ D μ controller. Comparative analysis of the SRM turn-on processes in both open and closed control systems with a classical integer-order PID controller and with a fractional-order PI λ D μ controller was made. Use of the fractional-order PI λ D μ controller in comparison with the classical integer-order regulator makes it possible to reduce overshoot from 13.3 % to 2.64 %, increase speed of the closed ACS, decrease regulation time from 1.48 s to 0.53 s while reducing variability of transient characteristics. The study results can be used to improve performance of closed systems for controlling angular velocity of the SRM

The Design of Flux Linkage Measurement for Switched Reluctance Motor

A Back Propagation neural network (BPNN) flux linkage model was proposed based on the measured magnetization curve for 8/6 poles switched reluctance motor (SRM). A flux linkage measuring installation is set up by using a digital signal processor (DSP) and measuring the voltage of winding under different rotor positions and different current values, then obtained the value of the corresponding flux linkage and the rotor magnetization characteristics of different positions.The flux linkage has higher accuracy. The design has the actual reference value to the high performance speed control of SRM.

Unipolar sinusoidal excited switched reluctance motor control based on voltage space vector

In order to improve the operation performance and decrease the torque ripple of switched reluctance motor (SRM), a new current control method for SRM based on voltage space vector was proposed. In which the stator windings are excited by sinusoidal current with a DC offset to realise the unipolar current excitation. In this control system, zero vectors were used to control zero-sequence current alone and non-zero voltage space vector was selected to control d–q-axis current considering coupling. The reluctance torque component was offset by injecting third harmonic current into the DC bias current, and copper loss was minimised by selecting appropriate current ratio. Experiences verified that the new method can effectively control SRM current. The torque ripple can be reduced with third times harmonic current injection, but the efficiency is also decreased. Compared with the traditional control method, the proposed method is simple, easy to implement, and can effectively suppress torque ripple.

Coupling effect between road excitation and an in-wheel switched reluctance motor on vehicle ride comfort and active suspension control

The coupling effect between road excitation and an in-wheel switched reluctance motor (SRM) on vehicle ride comfort is numerically analysed. A hybrid control system consisting of fault tolerant H∞ suspension controller and SRM controller for an in-wheel SRM driven electric vehicle is proposed to improve the vehicle ride comfort and motor operation performance. By conducting numerical simulations based on the developed quarter-car active suspension model and switched reluctance motor model, it is observed that the road roughness is highly coupled with SRM airgap eccentricity and unbalanced residual vertical force. The SRM airgap eccentricity is influenced by the road excitation and becomes time-varying such that a residual unbalanced radial force is induced; which is one of the major causes of SRM vibration. To suppress SRM vibration and to prolong the SRM lifespan, while at the same time improving vehicle ride comfort, a fault tolerant controller based on output feedback H∞ control method is designed to reduce the sprung mass acceleration. Moreover, an SRM controller is adapted by using the combined Current Chopping Control (CCC) and Pulse Width Modulation control (PWM) to further improve the SRM performance. A comparison of passive suspension and suspensions with hybrid control method on the vehicle and SRM dynamic response under stochastic road excitation and bump road excitation is illustrated. The results indicate that the proposed hybrid control method can effectively reduce the SRM airgap eccentricity, residual unbalanced radial force and achieve better vehicle ride comfort.

An improved simulation model of switched reluctance motor including transient core losses for steady-state operation

PurposeAn improved simulation model of switched reluctance motor (SRM) for steady-state operation that considers the core losses in the stator and rotor is established to obtain the steady performance of the high-speed SRM during the design, analysis and control of SRM driving system more accurately.Design/methodology/approachThe transient core loss model for the material and SRM is presented. Then a new method for calculating the flux density of the motor in real time is introduced, and a steady-state simulation model of the SRM including real-time transient core losses calculation model is established according to the transient flux density. Because the transient core losses calculated by above method are the total core losses of the motor, a core losses distribution method is proposed and the steady-state simulation model of the SRM including the distributed core losses’ effect on the phase winding is established.FindingsThe comparison results show that the proposed model has higher accuracy than the traditional model, excluding core losses, especially at the moments when phase voltage is turn-on and turn-off. The proportion of the core losses to the motor losses increases with the increase in speed. So, the core losses’ effect on the steady-state performance of the high-speed SRM cannot be ignored.Originality/valueThe method to obtain flux density in the real time is presented and the improved steady-state simulation model of SRM that considering transient core losses is proposed.

Review of Switched Reluctance Motor Control for Acoustic Noise and Vibration Reduction

Switched Reluctance Motor (SRM) is one of the candidates for substituting permanent magnet motor in Hybrid Electric Vehicle (HEV) application. Compared to permanent magnet motor, SRM is relatively low cost, robust, high reliability, and possible for high-temperature operation because of the absence of permanent magnet. One significant problem in SRM is the high acoustic noise and vibration. The vibration in SRM is caused by the radial forces acting at the stator teeth. Because of the saliency pole configuration in SRM, vibration is prominent. Many studies tried to reduce acoustic noise and vibration in SRM. In this paper, several controls for acoustic noise and vibration reduction are shown. The acoustic noise and vibration reduction from the experiment are also compared in each method.

An integrated converter model and enhanced control approach for torque ripple minimisation of switched reluctance motor: a CMFG-RNN technique

ABSTRACT In this paper, a control mechanism for speed control of switched reluctance motor (SRM) with torque ripple reduction utilising moth flame optimisation algorithm and genetic algorithm with recurrent neural network (CMFG-RNN) is presented. The control mechanism comprises of FOPID speed controller in the external loop and current controller in the internal loop along with control of turn-on and turn-off angles for the SRM. The issue of getting the ideal estimations of proportional, integral and derivative gains for both speed and current controller along with the turn-on and turn-off angles is considered as a multi-objective optimisation problem with the goals of limiting the Integral Squared Error of speed and torque ripple. Simulations of CMFG-RNN-based control of SRM are done utilising SIMULINK/MATLAB software. With a specific end goal to assess the strong execution of CMFG-RNN, the comparison of current, speed, flux and torque under different techniques are considered. The outcomes got by CMFG-RNN are contrasted and validated with ALO and NSGA-II techniques. The outcomes uncover that CMFG-RNN-based controllers give better execution as far as lesser torque ripple and quick settling time because of its systematic random search capabilities, thereby enhancing the dynamic execution of SRM drive.

A Direct Instantaneous Torque Control of Switched Reluctance Motor for Electric Vehicles based on FWA-LSSVM Improved ADRC

Electric vehicles are considered as a new generation of transport to solve the energy crisis, switched reluctance motor (SRM) has been widely used in electric vehicle drive system. Indirect instantaneous torque control (DITC) for SRM, Traditional PI regulator has some defects, A new direct instantaneous torque control for SRM based on active-disturbance rejection control (ADRC) optimized by least squares support vector machines (LSSVM) method is proposed in this paper, using the Firework Algorithm (FWA) to optimize the penalty factor and kernel parameters of the LSSVM model to obtain the optimal FWA-LSSVM regression model, Finally, the ADRC controller embedded the FWA-LSSVM optimal regression model is analyzed and optimized to improve the dynamic response speed and anti-jamming capability of the system and enhance the robustness of the system. MATLAB simulation results show that the feasibility and superiority of the method.

Cost-Effective Current Measurement Technique for Four-Phase SRM Control by Split Dual Bus Line Without Pulse Injection and Voltage Penalty

This paper proposes a simple and cost-effective current measurement technique for four-phase switched reluctance motor (SRM) control, by splitting the dual bus line of the converter, without pulse injection and voltage penalty. Only two Hall-effect sensors are utilized, where one is installed in the upper bus to measure two phase currents, and the other is placed in the lower bus to measure other two phase currents. In order to realize independent current measurement in the whole turn-on region, switching functions are redesigned so that upper switches of two phases act as the choppers, while lower switches of the other two phases are employed as the choppers. Compared to traditional drives, the developed system requires only two Hall-effect sensors in the dual bus line, without a need for individual phase sensors or additional devices, which reduces the cost and volume for SRM drives. Furthermore, compared to the single-sensor based current measurement scheme, the proposed method has no need to implement pulse injection and will not cause any voltage penalty and current distortion, which also improve the current measurement accuracy and system performance. Simulation and experiments carried out on a 150-W four-phase 8/6 SRM confirm the effectiveness of the proposed technique.

An advanced robust method for speed control of switched reluctance motor.

This paper presents an advanced robust controller for the speed system of a switched reluctance motor (SRM) in the presence of nonlinearities, speed ripple, and external disturbances. It proposes that the adaptive fuzzy control is applied to regulate the motor speed in the outer loop, and the detector is used to obtain rotor detection in the inner loop. The new fuzzy logic tuning rules are achieved from the experience of the operator and the knowledge of the specialist. The fuzzy parameters are automatically adjusted online according to the error and its change of speed in the transient period. The designed detector can obtain the rotor's position accurately in each phase module. Furthermore, a series of contrastive simulations are completed between the proposed controller and proportion integration differentiation controller including low speed, medium speed, and high speed. Simulations show that the proposed robust controller enables the system reduced by at least 3% in overshoot, 6% in rise time, and 20% in setting time, respectively, and especially under external disturbances. Moreover, an actual SRM control system is constructed at 220 V 370 W. The experiment results further prove that the proposed robust controller has excellent dynamic performance and strong robustness.

Design of Sliding Mode Speed Controller for Switched Reluctance Motor

Switched Reluctance motors (SRM) can be classified into a group of multi-speed electrical motors. The low cost, rugged constructions and simple are feature advantages for this motor. The simplicity is the result of their torque generation principle, which known as variable reluctance principle. The SRM has many more features that have made it to be common for applications in commercial and industrial markets. The main disadvantage of SRM is the nonlinearity that it appears in their dynamics because of the magnetic saturation. It is required for SRM speed controllers to have features such as fast dynamic responses, parameter insensitivity and quick recovery from load disturbances. In this paper, a design of a robust sliding mode speed controller based on a nonlinear mathematical model is proposed. Matlab/Simulink software is used to simulate switched reluctance motor drive system under control of SMC. 6/8 switched reluctance motor has been taken as case study. The performance of proposed sliding mode control is tested at different load and speed conditions, and comparisons with conventional PI control for switched reluctance motor are presented. The sliding mode controller exhibits a better performance than the PI controller for all the studied cases.

Torque‐ripple reduction of SRM using optimised voltage vector in DTC

High torque ripple is inherent in switched reluctance motors (SRMs) because of the motor's doubly salient structure and highly non-uniform torque and magnetisation characteristics. Direct torque control (DTC) for SRM is one of the torque ripple reduction strategies which gets wide attention for its simpleness and effectiveness. In this study, aiming at the torque ripple phenomenon of DTC for SRM, a novel method for torque-ripple reduction is proposed. With the new methods, sector zones were redivided into 9 and 12 sector zones based on six sector zones and new control rules were adopted. Consequently, the proposed methods make the selection of voltage vector more precise. A 12/8-pole three-phase SRM drive system was designed to verify the effectiveness of the proposed new methods. The results verified that the improved DTC algorithms with 9 and 12 sector zones could indeed minimise the torque ripple to a great extent.

New Drive Circuit for Reducing the Switching Current Ripples in Switched Reluctance Motors

SUMMARYThis paper proposes a new drive circuit for reducing the switching current ripples in a switched reluctance motor (SRM). The authors have already presented an instantaneous flat torque control for SRMs, and confirmed its effectiveness through experimental results. However, the switching current ripples also cause torque ripples, and therefore, the current ripples should be decreased to reduce the torque ripples even more. The proposed circuit with parallel capacitor can realize such a reduction. The validity of the proposed drive circuit is verified experimentally.

A fast switched reluctance motor controller based on FPGA

The paper presents the concept and practical implementation of a switched reluctance motor control system in an FPGA programmable device. The developed control system was designed for testing high-speed motors in order to limit the delays of output signals in relation to the signals from the encoder. The controller enables the values of commutation angles and PWM voltage to be set along with current limit values, measures the values of voltages and currents, and sends the results to the computer to be archived.