Independent Torque Control Research Articles

Speed regulation of PMSM drive in electric vehicle applications with sliding mode controller based on harris Hawks optimization

This paper focuses on the speed regulation of permanent magnet synchronous motors (PMSM) in electric vehicle application using sliding mode control (SMC). Harris hawks optimizations (HHO) based sliding mode controller is adopted to increase the dynamic response of the PMSM motor, thereby enhancing vehicle performance. For the independent control of torque and flux, field oriented-control (FOC) is used to drive the PMSM. In this work, the speed reference provided for the controller is based on an electric car driving cycle that replicates real-world driving conditions. The optimal selection of sliding mode controller parameter enhances the dynamic characteristics of the speed regulation in electric vehicles, which is validated using the hardware in the loop (HIL-402) device. The HHO based sliding mode controller has superior performance in terms of robustness against load disturbances, fast convergence, and tracking accuracy.

A Quick Dynamic Torque Control for an Induction-Machine-Based Traction Drive During Square-Wave Mode of Operation

In high power traction drives using induction motors, during operation above the base speed, it is generally preferred to drive the machine in the square-wave mode since it offers maximum DC-bus utilization and reduced switching loss. However, the conventional field oriented control method cannot control the drive effectively in square-wave mode since independent control of torque and flux is difficult to achieve due to stator voltage saturation. This paper proposes a new technique to control the drive in the square-wave mode where only one degree of freedom is available for control. In the square-wave mode, the proposed method controls the torque of the machine by directly varying the stator voltage angle with respect to the rotor flux axis. The flux of the machine is kept at a required value below the saturation limit by appropriate selection of the operating point. The proposed control strategy also offers good torque dynamics in the square wave operating mode. The control algorithm is experimentally verified on a 5.5 kW induction machine drive and the experimental results are presented.

Adaptive Center-of-Mass Relocation for Aerial Manipulator Fault Tolerance

This work proposes a fault tolerant aerial manipulator based on a standard hexarotor vehicle, which is able to maintain independent control of torque and vertical thrust in case of motor failure by adequately changing the manipulator configuration and therefore modifying the position of the system’s center of mass. By analyzing the disturbance torque that the manipulator exerts on the vehicle, conditions to achieve stable flight and operation limits are established. To provide an experimental proof of concept, several flights are performed, both in indoor and outdoor environments, for different size and weight of manipulators.

Axial Flux Topology Based Control Moment Gyroscope for Integrated Speed and Tilt Control

This paper presents a control moment gyroscope (CMG) for small satellites, driven and controlled based on axial flux motor principle. The presented structure is coreless with Halbach array rotor and a stator to control the rotational speed/torque and effective gimbal rate/ angle. This topology allows a relatively simple mechanical structure with an equivalent dual gimbal control for limited angle. There are two sets of windings for torque generation along three orthogonal axes, one is 8 pole and other is 6 pole. The winding structure is novel in the sense of accommodating different number of poles <formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex>$ (&gt;4)$</tex></formula> using the same stator slots. Two 3 phase inverters are used to accurately control the torques by energising two sets of windings. Analytical formulation is provided to understand various torque generation mechanisms and 3D FEM simulations are performed to verify the operation and to get better quantitative torque generation capabilities of the CMG along different axes. Finally, a quick experiment prototype is developed to verify the operation with open loop speed control and closed loop tilt position control more qualitatively with off the shelf available components. Independent control of torque in 3 axes was achieved experimentally and the results are explained.

Reduced-Order Feedback Linearization for Independent Torque Control of a Dual Parallel-PMSM System

Connecting two PMSMs in parallel to a 2-level 3-leg inverter gives a way to build up a high power-density driving system using existing electronic devices. But this type of system has a nature of nonlinearity that creates an obstacle in high performance control and the original system cannot be feedback-linearized directly. This article presents a reduced-order feedback-linearization method. In the first place, an extra order-reducing step that separates the system as a main system and an auxiliary system is applied. Then a feedback-linearization method is applied to the reduced-order system. With these effort, the original system can be converted into a linear time-invariant system bringing the controller design problem into the linear domain. In the last step, a linear robust state-feedback controller is used to achieve the speed control as well as compensate the unmeasurable external load torque. An extensive experiment is given to verify the feasibility and good performance in a highly unbalanced load torque situation of the designed controller.

A Novel Matrix Transformation for Decoupled Control of Modular Multiphase PMSM Drives

When multiphase drives are used for specific applications, the modular solutions are preferred as they use consolidated power electronics technologies. The literature reports two modeling approaches for multiphase machines having a modular configuration of the stator winding. The first approach is the vector space decomposition (VSD) that models the energy conversion as for an equivalent three-phase machine. The main alternative to the VSD is the multistator (MS) modeling that emphasizes machine modularity in terms of torque production. Both approaches have advantages and disadvantages for multiphase machines with a modular structure. Therefore, this article aims to combine the VSD and MS approaches, defining a new matrix transformation and, hence, developing a new modeling approach for multiphase machines with a modular structure. The proposed transformation allows a decoupled and independent torque control of the sets composing the machine, preserving the torque regulation's modularity. Together with a new vector control scheme, it has been applied to a modular permanent magnet synchronous machine (PMSM) with a nonstandard spatial shift between windings. Experimental results are presented for a nine-phase PMSM prototype with a triple-three-phase stator winding configuration.

저심도 도시철도용 개별 모터의 횡변위 복원력제어를 통한 틸팅력 보상 알고리즘 제어 전략

In connection with the introduction of new public transportation due to urbanization, research on low-depth urban railways has been actively conducted. When the independently driving type is applied to such a low-depth urban railway, the independent torque control of the left and right wheels can be performed independently, but the mechanical resilience is weak because there is no wheeling. In order to make up for this drawback, a control method through the lateral displacement restoring force is proposed. It is proposed to an algorithm that makes restoring force stronger by controlling each motor of left and right wheels individually. This algorithm is also verified through MATLAB / SIMULINK.

An Elbow Exoskeleton for Upper Limb Rehabilitation With Series Elastic Actuator and Cable-Driven Differential

Movement impairments resulting from neurologic injuries, such as stroke, can be treated with robotic exoskeletons that assist with movement retraining. Exoskeleton designs benefit from low impedance and accurate torque control. We designed a 2 degree-of-freedom tethered exoskeleton that can provide independent torque control on elbow flexion/extension and forearm supination/pronation. Two identical series elastic actuators (SEAs) are used to actuate the exoskeleton. The two SEAs are coupled through a novel cable-driven differential. The exoskeleton is compact and lightweight, with a mass of 0.9 kg. Applied RMS torque errors were less than 0.19 Nm. Benchtop tests demonstrated a torque rise time of approximately 0.1 s, a torque control bandwidth of 3.7 Hz and an impedance of less than 0.03 Nm/deg at 1 Hz. The controller can simulate a stable maximum wall stiffness of 0.45 Nm/deg. The overall performance is adequate for robotic therapy applications and the novelty of the design is discussed.

Design and Construction of a Wind Turbine Simulator for Integration to a Microgrid with Renewable Energy Sources

In this paper, a physical wind turbine simulator (WTS) has been designed, constructed, and evaluated in a microgrid environment. The reference turbine is a physical wind turbine (PWT), whose characteristics are obtained through wind tunnel experiments. The main purpose of this WTS is to investigate the integration and coordination control of wind energy systems in a microgrid environment. A comprehensive literature review has been performed, and the lessons learned from existing WTSs have been considered. A vector torque control strategy with an induction motor has been selected for implementation. Due to the feature of independent torque control in a vector mode, superior dynamic behavior, high accuracy at low-wind speed conditions can be achieved. This simulator, therefore, provides flexibility to accommodate a wide range of wind conditions. In addition, the simulator construction and control system design are also included. The steady-state and dynamic characteristics of the WTS correlate well with the considered reference PWT. The performance of WTS has been validated against the reference turbine under realistic wind conditions. Real-time coordination of this WTS with photovoltaic (PV) devices and battery storage within a microgrid has been also investigated.

Control strategy of four-wheel independent drive electric vehicle based on vehicle velocity estimation and switchover

The four-wheel independent drive electric vehicle (4WID EV) has some advantages, such as independent control of torque, easy measurement of torque, and multiple drive modes, the most significant of which are four-wheel drive and two-wheel drive modes. However, there is a problem with the switched drive mode, which would have an adverse effect on the precision of vehicle velocity estimation, the vehicle stability and comfort. In order to solve the problem, a control strategy with a switched drive mode is proposed. The control strategy is based on two vehicle velocity estimation algorithms. Between the two vehicle velocity estimation algorithms, the vehicle velocity estimation algorithm based on an unscented Kalman filter is designed in a four-wheel drive mode condition, whereas the vehicle velocity estimation algorithm based on the wheel rotational speed is designed in a two-wheel drive mode condition. Switchover of the two vehicle velocity estimation algorithms would cause a vehicle velocity saltus step, which has an adverse effect on vehicle control, so a vehicle velocity smoothing algorithm is proposed. Simulation results show that the control strategy not only reaches a high vehicle velocity control accuracy, it also improves the vehicle stability as well as the comfort. Furthermore, the results show that the proposed strategy can achieve stabilization with disturbance.

Torque Distribution Algorithm for an Independently Driven Electric Vehicle Using a Fuzzy Control Method

The in-wheel electric vehicle is expected to be a popular next-generation vehicle because an in-wheel system can simplify the powertrain and improve driving performance. In addition, it also has an advantage in that it maximizes driving efficiency through independent torque control considering the motor efficiency. However, there is an instability problem if only the driving torque is controlled in consideration of only the motor efficiency. In this paper, integrated torque distribution strategies are proposed to overcome these problems. The control algorithm consists of various strategies for optimizing driving efficiency, satisfying driver demands, and considering tire slip and vehicle cornering. Fuzzy logic is used to determine the appropriate timing of intervention for each distribution strategy. A performance simulator for in-wheel electric vehicles was developed by using MATLAB/Simulink and CarSim to validate the control strategies. From simulation results under complex driving conditions, the proposed algorithm was verified to improve both the driving stability and fuel economy of the in-wheel vehicle.

Coupling characteristics and control of dual mechanical port machine with spoke type permanent magnet arrangement

Dual mechanical port machine(DMPM), as a novel electromechanical energy conversion device, has attracted widespread attention. DMPM with spoke type permanent magnet arrangements(STPM-DMPM), which is one of several types of DMPM, has been of interest recently. The unique coupling characteristics of STPM-DMPM are beneficial to improving system performance, but these same characteristics increase the difficulties of control. Now there has been little research about the control of STPM-DMPM, and this has hindered its practical application. Based on a mathematical model of STPM-DMPM, the coupling characteristics and the merits and demerits of such devices are analyzed as applied to a hybrid system. The control strategies for improving the disadvantages and for utilizing the advantage of coupling are researched. In order to weaken the interaction effect of torque outputs in the inner motor and the outer motor that results from coupling in STPM-DMPM, a decoupling control method based on equivalent current control is proposed, and independent torque control for the inner motor and outer motor is achieved. In order to solve address the problem of adequately utilization of coupling, minimizing the overall copper loss of the inner motor and the outer motor of STPM-DMPM is taken as the optimization objective for optimal control, and the purpose of utilizing the coupling adequately and reasonably is achieved. The verification tests of the proposed decoupling control and optimal control strategies are carried out on a prototype STPM-DMPM, and the experimental results show that the interaction effect of torque outputs in the inner motor and the outer motor can be markedly weakened through use of the control method. The overall copper loss of the inner motor and the outer motor can be markedly reduced through use of the optimal control method, while the power output remains unchanged. A breakthrough in the control problem of STPM-DMPM is accomplished by combining the control methods. Good performance in the control of STPM-DMPM will enhance its practicality, particularly as applied to hybrid systems.

Microcontroller based Stator Winding Resistance Determination of Induction Motor Drive on Temperature Variations

In this paper an experiment has been conducted to determine the online stator winding resistance of an induction motor, in industries as well as domestic purpose induction motors is largely utilized, as it has both applications of variable and constant torque operation nature. The major requirement of an electric drive system is its independent control of torque and speed; this is achieved in DC motor Drive but has more disadvantages. With the help of fast acting switching devices it is possible to independently control an induction motor. To control an induction motor drive various methods are available, direct torque control of induction motor is one of the best method of control compared to other, the only disadvantage is the torque ripple. Stator resistance is one of the parameter for the cause; hence its determination is essential. An experiment is conducted at various loads on an induction motor and then the temperature in the stator winding is noted at different instants using microcontroller, from the tabulated readings stator winding resistance is calculated and compared with the direct measurement by Volt-Ampere method. Further it is suggested that by implementing the actual online value of stator resistance of an induction motor dive torque ripple can be minimized .

Indirect Field Orientation Control of Induction Machine With Detuning Effect

Induction motors (IM) arc characterized by complex, highly nonlinear time varying dynamics and inaccessibility of some states and outputs for measurements and hence may be considered as a challenging problem. Field orientation control (FOC ) methods of an induction machine achieve decoupled torque and flux dynamics leading to independent control of torque and flux as for separately excited DC motor, but there are sensitive to motor parameter variations. The present work select the indirect field orientation control (IFOC) as an effective method for eliminating the coupling effect. The results showed how well the drive performance has been improved by this control strategy. However, to what extent the control strategy can perform the decoupling relies on the accuracy of the slip frequency calculation. Unfortunately, the slip frequency depends on the rotor time constant that varies continuously according to the operational conditions and then the coupling effect may again arise. This paper investigates the improvement in the performance of the induction machine dynamics as the IFOC technique is utilized. Also, it investigates the degradation in dynamic performance when the rotor resistance is deviated from its nominal value.

Control of two PM linear motors with a single inverter: application to elevator doors

This work considers the control of two PM synchronous motors using a single inverter. The standard approach to the control of a PM synchronous motor is to use a single inverter which provides independent control of the direct and quadrature voltages (and therefore of the direct and quadrature currents) of the motor. Here, an approach is presented that provides independent torque control of two PM synchronous motors using a single inverter. In this approach, the quadrature current of each motor is controlled while it is shown that the direct current is uncontrollable. Both parallel and series connections of the two motors to the single inverter are considered and it is shown how the singularity of the controller can be avoided in each case. The methodology is applied to the control of elevator doors.

Alternative implementation of vector control for induction motor and its experimental evaluation

An implementation of vector control for induction motors is presented, where there is no need for information concerning the rotor flux position and matrix transformations. It shows how the stator reference phase currents can be generated and changed in real time from digitally stored sinewaves, so to achieve independent control of torque at constant rotor flux. Experimental evaluation of the new scheme is made for sudden changes in the load torque and for the step changes of the speed reference signal. The arrangement of a DC load system enabling sudden changes in load torque is also described.

Design and performance of field regulated reluctance machine

A unique topological configuration for rotating electromagnetic machines that can produce significantly higher force density than an induction machine is investigated. The stator is constructed using full pitch concentrated windings embedded in conventional slots. Rotor saliency is produced using poles constructed of axially oriented laminations. Operation is such that all of the conductors are actively taking part in torque production all of the time. The means for exciting the stator windings allows for independent control of torque and regulation of the rotor flux. A force density comparison is made based on operation with equal surface current density, conduction losses, and peak air-gap flux density. Construction and testing of a prototype 500 RPM, 28 kW laboratory machine, power converter, and controller are described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Multivariable Control of an Engine/Dynamometer Test RIG

Recent concern with pollution has caused further studies on petrol engines to become necessary with a view to reducing their contribution to pollution of the atmosphere. An existing analogue model of an engine/dynamometer test rig is used to study the independent control of torque and speed developed by such engines, so that the engines can be put through a test cycle which will simulate normal road driving conditions. Three models of the system are considered having order 3, 5 and 5, and two separate design approaches are considered; namely, complete decoupling of the two output parameters using the state-feedback approach, and Rosenbrock’s Inverse Nyquist Array (INA) method. In all cases, the INA approach results in simpler and more manageable control schemes.