Wide Speed Range Operation Research Articles

Improved Closed-Loop Flux Observer Based Sensorless Control Against System Oscillation for Synchronous Reluctance Machine Drives

Flux-linkage based sensorless control method is well-known and has been widely used in the control of electrical machines. The closed-loop flux observer (CLFO), which is the adaptive combination of the machine voltage and current models, is commonly adopted. It can cover a wide speed operation range and was considered to be able to solve the dc drift and initial value problem associated to the pure integrator used in the observer. However, it is reported in this paper that this popular CLFO cannot always work as expected. In some situations, dc-offsets cannot be removed by this flux observer, causing large system oscillation at fundamental frequency and is very harmful to the drive system. This important issue has not been reported and discussed in the existing literatures of the CLFO. In this paper, this phenomenon is experimentally illustrated and solution to damp this harmful oscillation is proposed and verified experimentally on a synchronous reluctance machine drive system.

Third Harmonic Injection Based Nonlinear Control of IPMSM Drive for Wide Speed Range Operation

This paper presents a third harmonic injection (THI) based nonlinear controller for a wide speed range operation of interior permanent magnet synchronous motor (IPMSM) drive. Due to magnetic saturation, constant motor parameters lead to an unsatisfactory performance for the controller. Therefore, an adaptive backstepping based nonlinear controller is developed for an IPMSM drive to achieve high dynamic performance coping with parameter uncertainties. A sinusoidal THI technique is integrated to increase the dc bus utilization, which facilitates a higher operating speed range. The field control permits extended speed range utilizing the reluctance torque and field weakening. Stability of the control law state variables are demonstrated through Lyapunov stability criterion and global asymptotic stability of the drive is assured through the application of criterion supported by Barbalat's lemma. Feasibility of the proposed drive is tested in both simulation and experiment for laboratory 3.73 kW IPMSM drive. A performance comparison of the proposed THI-based nonlinear controller is shown with conventional benchmark tuned PI controller, and nonlinear controller without THI. Rapid convergence to command speed, reduction in speed oscillations over the rated speed, and a visible reduction in phase current with THI is achieved through the proposed drive.

Dynamic control of electronic differential in the field weakening region

ABSTRACTA simple and dynamic electronic differential control method for an outer rotor motor driven electric vehicle based on fuzzy gain scheduling of PI gains method is proposed for constant torque and power region operation using brushless direct current (BLDC) machine. The proposed method is quite insensitive to torque fluctuations and transient speed oscillations due to surface mounted permanent magnet (SMPM) BLDC machines constraints in the field weakening region. To improve the dynamics and stability of the electronic differential system and eliminate the skidding of the wheels and reduce the heating of electric machine in the wide speed range operation, a robust control method is developed. Moreover, PI controller gains are updated continuously by fuzzy gain scheduling approach which has phase advance angle, steering angle and measured speed as controller input parameters in order to eliminate the errors caused from the variable road conditions and torque oscillations in the field weakening region. The proposed method is implemented with 2 × 1.5 kW BLDC motor drive controlled by a TMS320F28335 digital signal processor (DSP). The experimental results show that the proposed method exhibits greater stability under various load, road and vehicle speed conditions.

Optimal Design and Performance Analysis of Double Stator Multi-Excitation Flux-Switching Machine

Due to its special partitioned stator structure and multi-excitation with two different types of permanent magnet, a new double-stator multi-excitation flux-switching machine (DSME-FSM) has advantages of high torque density, wide speed range, and low cost. For this kind of machine with complex structure, in order to realize the optimization accurately and efficiently, a multi-objective comprehensive optimal design method considering the different weights of the design objectives is presented based on parameters sensitivity analysis and genetic algorithm optimization in this paper. The parametric model of the machine is built up, and a trade-off objective function considering the different weights of the design objectives is defined. The key size parameters with strong sensitive are selected through parameters sensitivity analysis and then optimized by using the genetic algorithm method. The performance comparison between the initial and the optimized machines verifies the proposed optimization method. The anti-demagnetization property and the flux-weakening capability for a wide-speed range operation are also analyzed, which further confirms the DSME-FSM an interesting candidate for EV propulsion.

Winding Switching and Turn Switching in Permanent Magnet Vernier Machines for Wide Speed Range Operation and High Efficiency

This paper proposes to turn to switch along with winding switching for high-efficiency of permanent magnet vernier machines (PMVM) during wide speed range operation for electric vehicles application. For winding switching, the three-phase winding of the machine is divided into two sets of windings, namely, winding set A, B, C and winding set X, Y, Z. For turn switching, the number of turns for one set of winding is changed. With the different number of turns for winding set X, Y, Z, the efficiency of the machine can be significantly improved. Initially, the basic electromagnetic characteristics, such as the flux linkage, back electromotive force (EMF), torque, and phase voltages of the machine are investigated using winding switching and turn switching. Then, the output power, torque-speed curve, core losses, efficiency, and power factor of the machine are analyzed in detail using a different number of turns. In addition, the transient effects of winding switching and turn switching have been analyzed. Finally, a control strategy is proposed which combines turn switching and winding switching to ensure high-efficiency of PMVMs during wide speed range operation. A PMVM is designed and driven in accordance with the proposed control strategy (PCS) to show the characteristics of PCS. The PMVM driven with PCS is compared to a recently presented PMVM. The recently presented PMVM is driven by a different control strategy and is analyzed with two different kinds of steel laminations that are general steel (50TW470) and special steel (20JHF1300).

PSO Optimized PID Regulator for a Variable Frequency Brushless Synchronous Generator

The aim of this paper is to describe development of a new control structure for Automatic Voltage Regulator system. This approach is based on the optimization of the control voltage magnitude of a brushless excitation synchronous alternator machine operating at variable speed. The choice of the machine type is justified by its attractiveness in several areas such as the aircraft domain due to its autonomy and robustness. The considered control technique is based on the simultaneous optimization of two regulators introduced in the loop control. The parameters of the Proportional Integral Derivatives (PID) regulator have been optimized using the Particle Swarm Optimization (PSO), which is considered as an attractive method considering the wide operating speed range, and the load variations compared with the classical methods such as Ziegler Nichols. Many robustness tests are carried out by considering the parameters variations as well as the perturbation connection and disconnection of the load at low and high speeds.

Wide speed range operation of permanent magnet vernier machines

This letter proposes winding switching for the high-performance of permanent-magnet vernier machines (PMVMs) in wide speed range operation. The machine is operated in two modes: cumulative and differential. Before winding switching (cumulative mode), the machine is operated like a conventional three-phase PMVM. The machine provides high torque density and high efficiency in this mode. After winding switching (differential mode), the back EMF and inductance of the machine are decreased significantly, which enable wide speed range operation and the attainment of high power factor in high-speed operation.

Experimental Analysis of Simplified Rules Fuzzy Logic Speed Controller for Wide Speed Range Operations

<p>This paper presents the experimental analysis of simplified rules Fuzzy Logic Speed Controller (FLSC) of Induction Motor drive. The maximum gain of input scaling factor, FLSC is generally limited by the coverage of universe of discoursed (UoD). Thus, to further increase the input gain scaling factor, the outer membership function need to be increased. This analysis covers various values in the range of UoD values from [-1,1] to [-5,5] for the wide speed range operations from low to rated speed ranges. The FLSC is employed to the indirect Field Oriented Control method fed by a voltage source inverter. Simulation and experimental verification is done by using Matlab/Simulink and dSPACE 1103 controller experimental rigs respectively. Based on the results, speed performance behaviours are improved over the wide speed range operations in term of rise time and setting time. The tuning approached is simple without additional algorithm for faster and more accurate response.</p>

Wide Speed Range Operation by Low-Voltage Inverter-Fed MATRIX Motor for Automobile Traction Motor

This research proposes a novel low-voltage inverter-fed motor drive with variable parameters achieved through the independent armature winding for the automobile traction motor. The independent armature winding with low-voltage inverters can improve the total efficiency by reducing the converter losses. The inverters are able to change their connections to different coils groups of the armature winding in order to achieve the wide operating range. The voltage equation of each mode can be shown by using the transformation matrix when the winding connection is changed. Thus, the proposed motor is called the MATRIX motor. In this paper, the downsized model was designed to verify the principle. The principle model is able to achieve four motor parameters. It was confirmed that the principle model could extend the operating range and could achieve the high-efficiency driving in wide speed range. Furthermore, the novel winding reconfiguration method is proposed that not only avoids the surge voltage, but also compensates the torque reduction during the winding reconfigurations.

Extended Kalman Filter Based Sliding Mode Control of Parallel-Connected Two Five-Phase PMSM Drive System

This paper presents sliding mode control of sensor-less parallel-connected two five-phase permanent magnet synchronous machines (PMSMs) fed by a single five-leg inverter. For both machines, the rotor speeds and rotor positions as well as load torques are estimated by using Extended Kalman Filter (EKF) scheme. Fully decoupled control of both machines is possible via an appropriate phase transposition while connecting the stator windings parallel and employing proposed speed sensor-less method. In the resulting parallel-connected two-machine drive, the independent control of each machine in the group is achieved by controlling the stator currents and speed of each machine under vector control consideration. The effectiveness of the proposed Extended Kalman Filter in conjunction with the sliding mode control is confirmed through application of different load torques for wide speed range operation. Comparison between sliding mode control and PI control of the proposed two-motor drive is provided. The speed response shows a short rise time, an overshoot during reverse operation and settling times is 0.075 s when PI control is used. The speed response obtained by SMC is without overshoot and follows its reference and settling time is 0.028 s. Simulation results confirm that, in transient periods, sliding mode controller remarkably outperforms its counterpart PI controller.

Design studies of inner and outer embedded Permanent Magnet for hybrid electric vehicles

Hybrid vehicles require high torque for propel, hence permanent Magnet machines are highly suiting for the improvement in the torque density. The paper focus on designing built-in interior permanent magnet (IPM) synchronous machine for hybrid electric drive. With the permanent magnet switched from rotor to stator and the characteristics over a wide range of speed operation is studied. The results obtained though performance analysis shows that at 130 rpm high torque with power peaking at around 900 rpm. Both the inner and outer machine are studied using numerical study tool for performance analysis for the application mentioned above. The inner magnet rotor design has provide a better magnetic flux flow due to the larger flux linkage between the permanent magnet and stator pole. Both type of machines are evaluated for torque where the machine with inner magnet provide a higher torque density of 4.94% as compared to the outer magnet machines.

Application of Second-Order Sliding-Mode Concepts to Active Magnetic Bearings

Rotor mass imbalance is a common problem to rotating machines due to the unavoidable imperfections in manufacturing. These imbalance forces can be viewed as harmonic disturbances which lead to a periodic rotor runout during rotation. Furthermore, the runout length increases with the rotational speed squared. Moreover, for variable rotational speed applications, these harmonic disturbances are also time-varying. Active magnetic bearings (AMB) provide a means of actively attenuating these disturbances. Although various imbalance compensation schemes have been proposed in the literature to handle this problem, they are often more suitable for constant rotational speed applications where disturbances can be handled at a predetermined rotational speed. This study proposes the application of second-order sliding-mode control (2-SMC) to regulate AMB systems throughout a wide operating speed range. The proposed controllers are composed of two components. The first component is a linear controller for the sake of stabilizing the inherently unstable system, while the second component is a 2-SMC to handle the model uncertainties of the system as well as the exogenous harmonic disturbances. Simulation and experimental results are provided to demonstrate the effectiveness and superiority of the proposed techniques compared to the conventional linear controller.

A Partitioned-Stator Flux-Switching Permanent-Magnet Machine With Mechanical Flux Adjusters for Hybrid Electric Vehicles

In this paper, three partitioned-stator (PS) machines, namely the PS flux-switching permanent-magnet (PS-FSPM) machine, the PS-FS hybrid-excitation machine, and the flux adjuster PS-FSPM (FA-PS-FSPM) machine are proposed for the hybrid electric vehicles (HEVs). Owing to the installation of additional inner-stators, all three proposed machines can offer satisfactory power and torque densities. In particular, the FA-PS-FSPM machine artfully utilizes its inner space to accommodate the mechanical FAs, such that outstanding flux-weakening capability for wide-speed range operation can be achieved. To verify the proposed concept, the established machines are purposely compared with the profound Prius HEV machine based on finite-element method.

A Robust Flywheel Energy Storage System Discharge Strategy for Wide Speed Range Operation

Wide speed range operation in discharge mode is essential for ensuring discharge depth and energy storage capacity of a flywheel energy storage system (FESS). However, for a permanent magnet synchronous motor/generator-based FESS, the wide-range speed variation in a short discharge period causes consecutive decreases in ac voltage frequency and amplitude. As a result, operation point shift leads to performance deterioration of the conventional local linearization based dc-link voltage control strategies. This study aims to realize a consistent robust discharge performance within the entire available operation range for FESS. We propose a robust discharge strategy that incorporates the speed variation to the dc-link voltage controller. A speed-dependent extended state observer is designed to realize global linearization and enhance the robustness. A speed adaptive feedback control law is designed to ensure consistent dynamic performance within the entire available operation range. Finally, the discharge strategy is validated at different speeds on a high-speed FESS test bench.

Unified Wide-Speed Sensorless Scheme Using Nonlinear Optimization for IPMSM Drives

This paper proposes a novel unified nonlinear optimization-based speed and position estimation algorithm for interior permanent magnet synchronous motor drives at wide speed range operations. A cost function based on the voltage equations in the stationary reference frame is employed for speed and position estimation. The speed and position can be estimated by minimizing the cost function. At low speed, including the standstill condition, the cost function is modified and high-frequency sinusoidal voltage signals are injected in the estimated magnetic axis. A phase locked loop is combined with the proposed position estimator for reducing the noise of estimation results. Compared with existing sensorless methods, a unified estimator is used at low- and high-speed operations and a better performance is obtained in transient and steady-state conditions. The convexity of the cost functions with respect to the speed and position estimation errors is analyzed in the paper. The feasibility of the proposed estimation algorithm is validated with an experimental test bench.

A Stator-PM Consequent-Pole Vernier Machine With Hybrid Excitation and DC-Biased Sinusoidal Current

This paper proposes a novel hybrid excitation vernier permanent magnet machine (HE-VPM). The characteristics of the proposed machine are: 1) the PMs are embedded in the stator teeth, which is helpful for the heat dissipation; 2) the rotor is salient structure without PMs and windings, which ensures the reliability of high-speed operation; 3) the nonoverlapping concentrated winding shortens the end-connection, and improves the torque density, 4) only half of the stator teeth possess PMs, and the total amount of PMs are decreased; and 5) the dc current are injected to the armature coils, therefore, the exciting field can be adjusted flexibly. In this paper, the electromagnetic performance, including back electromotive force, torque, etc. are analyzed with finite element analysis. The results show that the proposed machine exhibits flexible field adjustment capability, which may be suitable for applications requiring wide speed range operation. Besides, it is found that, compared with the existing pure sinusoidal phase current, higher torque density can be obtained with dc-biased phase current under constant stator copper loss.

Robust speed regulation of indirect vector control induction motor using fuzzy logic controllers based on optimization algorithms

Currently, in high-performance applications, the vector control (VC) scheme of induction motor (IM) is widely employed in industry. The VC scheme has significant features of decoupling torque and flux; also, its hardware implementation is easier. Conventionally, PID control schemes are frequently used for variable speed operation. However, the performance of the VC scheme is limited over a wide range of speed operation because of de-tuning caused by parameter uncertainties. To address the aforementioned challenging problem, adaptive and robust control strategies are mostly implemented. This paper presents various novel, adaptive, and robust control strategies, namely (a) fuzzy logic controller (FLC) based on Levenberg–Marquardt algorithm (LMA), (b) FLC based on steepest descent algorithm (SDA), (c) FLC based on Newton algorithm (NA), and (d) FLC based on Gauss–Newton algorithm (GNA) for the indirect vector control (IVC) three-phase IM. The focal motive is to accomplish fast dynamic response with fault-tolerant capability, load disturbance rejection qualities, insensitivity to the parameter uncertainties, robustness to speed variation, and to acquire maximum efficiency as well as torque. The \(d-q\) modeling of the IVC IM in the synchronous reference frame and space vector pulse width modulation (SVPWM) employed in inverter are designed in MATLAB/Simulink. Our work also presents critical, analytical, and comparative assessment of the proposed controllers with traditional tuned PI control strategy for the electrical faults perturbation, load disturbances, speed variations, and parameter uncertainties. Furthermore, the simulation results of the above-mentioned designed control strategies validated robust, smooth, and faster response with permissible overshoot, undershoot, settling time, and rise time for the IVC IM drive system, compared to prior works.

Concentrated Winding IPM Synchronous Motor Design for Wide Field Weakening Applications

In order to understand the impact that certain design changes may have on the performance over a wide speed range, a series of 12-slot 8-pole concentrated winding interior permanent magnet synchronous motors (IPMSMs) are analyzed. Fundamental theory of operation is used to describe the desirable characteristics in terms of the lumped parameters, and finite element analysis is carried out to show how these characteristics may be realized through the motor geometry changes. The motor geometry changes aim to create an IPMSM design with high d -axis inductance for the wide speed range operation, low harmonic content in the back electromotive force waveform, and low cogging torque. A prototype is constructed and test results are presented for verification.

Scalar controlled induction motor drive speed estimation by adaptive sliding window search of the power signal

This work reports an improved estimation reliability wide range rotor speed estimation algorithm for scalar controlled wound rotor induction machines using spectral search of the stator power signal. An adaptive sliding window speed estimation method is proposed that monitors the value of supply frequency to identify the optimum boundaries of the power signal narrowband maximised by a tracked speed dependent power harmonic, while adjusting to nominal slip variation with supply frequency change characteristic of scalar controlled machines. Analytical expressions are derived that allow direct correlation of the surveyed spectral window boundaries to supply frequency. Once identified, the optimal power spectral narrowband enables supply frequency independent speed evaluation. The proposed method is underpinned by a dichotomous search based frequency tracking technique enabling improvement in the attainable estimation rate. The presented technique’s performance and limitations are assessed in steady-state and transient operation real-time experiments on two different scalar controlled 7.5kW machines. The scheme is shown to provide competent real-time speed estimation in a wide operating speed range for lower dynamics transients and steady-state operation.

Comparative investigation of vibration and current monitoring for prediction of mechanical and electrical faults in induction motor based on multiclass-support vector machine algorithms

This paper presents an investigation of vibration and current monitoring for effective fault prediction in induction motor (IM) by using multiclass support vector machine (MSVM) algorithms. Failures of IM may occur due to propagation of a mechanical or electrical fault. Hence, for timely detection of these faults, the vibration as well as current signals was acquired after multiple experiments of varying speeds and external torques from an experimental test rig. Here, total ten different fault conditions that frequently encountered in IM (four mechanical fault, five electrical fault conditions and one no defect condition) have been considered. In the case of stator winding fault, and phase unbalance and single phasing fault, different level of severity were also considered for the prediction. In this study, the identification has been performed of the mechanical and electrical faults, individually and collectively. Fault predictions have been performed using vibration signal alone, current signal alone and vibration-current signal concurrently. The one-versus-one MSVM has been trained at various operating conditions of IM using the radial basis function (RBF) kernel and tested for same conditions, which gives the result in the form of percentage fault prediction. The prediction performance is investigated for the wide range of RBF kernel parameter, i.e. gamma, and selected the best result for one optimal value of gamma for each case. Fault predictions has been performed and investigated for the wide range of operational speeds of the IM as well as external torques on the IM.