Torque Control Of Induction Motor Research Articles

Finite Control Set Model Predictive Torque Control of Induction Motors using a Neutral Point Clamped Three-Level Inverter with Computational load Reduction

In this paper, a FCS-MPC strategy for the torque control of 3 phase induction motors using a NPC type 3-level inverter is proposed. It derives a reference state for the given torque reference. Use of a performance index penalizing tracking error for the reference state. Here we propose to confine the evaluation of the performance index to 3 voltage vectors of the 3-level inverter considering the fact that the dynamics of the electrical system is far faster than that of mechanical system. Thus the computational load is not increased compared to earlier FCS-MPC methods based on 2-level inverters. An effective method to maintain the balance of dc capacitors is also proposed. The efficacy of the proposed method is proved simulations.

Fuzzy direct torque control for induction motor drive system based on space vector modulation

A new approach of a fuzzy direct torque control and drive (FDTC) for induction motor drive system based on space vector modulation (SVM) technology is proposed in this paper. By comparing the conventional direct torque control using space vector modulation technology (SVMDTC) method with the fuzzy direct torque control, a fuzzy controller is used to replace the PI conventional speed regulator. In the proposed strategy, the error between the estimated and the referred linkage flux of the stator and torque will be compensated by an accurate synthesised space vector voltage. Simulation results show that the proposed SVM-DFTC method can improve the system robustness, evidently reduces flux and torque ripples, and in turn obtain a swift speed response with extraordinarily high improvement of its performance.

Model Predictive Torque Control of Induction Motor Drives With Optimal Duty Cycle Control

Model predictive torque control (MPTC) is emerging as a powerful control scheme for high performance control of induction motor (IM) drives. Compared to direct torque control, MPTC is more effective and accurate in voltage vector selection by incorporating the system model directly with the finite switching states. However, for two-level inverter-fed IM drives, the sampling frequency of MPTC has to be high to achieve good performance due to the limited number of voltage vectors. Recently, the concept of duty cycle control was introduced in MPTC by inserting a null vector along with the selected active voltage vector to achieve torque ripple reduction. The active vector is first selected from conventional MPTC and then its duration is determined based on a certain principle. The cascaded processing of active vector and its duration leads to poor low-speed performance and the sampling frequency still has to be high. This paper proposes an improved MPTC with duty cycle control by optimizing the vector selection and its duration simultaneously when minimizing both torque and flux errors. As a result, better steady-state performance at both low and high speeds is achieved, even if the sampling frequency is reduced by half. The effectiveness of the proposed MPTC is verified by both simulation and experimental results.

Direct Torque Control of Induction Motors Based on Discrete Space Vector Modulation Using Adaptive Sliding Mode Control

—Direct torque control (DTC) with space vector modulation (SVM) ensures constant switching frequency and high-performance operation, both in the steady state and under transient conditions. This article is devoted to the presentation of a comparison study between two DTC-SVM approaches for electric propulsion systems applications: (i) DTC-SVM with controllers, and (ii) DTC-SVM with sliding mode controllers. Following the formulation of both DTC-SVM approaches, their implementation in the Matlab-Simulink environment has been treated. The transient behavior as well as the steady state features of the drive system under both approaches are compared and commented. The robustness with respect to parameter variations of the induction motor drive is also tested. Simulation results show the effectiveness and the robustness of the proposed DTC-SVM adaptive sliding mode control against variations of induction motor parameters.

Analysis of Direct Torque Control of Industrial Drives using Zone-Shifting SVM

Direct Torque Control of Induction Motor has gained popularity in industrial applications mainly due to its simple control structure from its first introduction in 1986. Here the direct torque control (DTC) of induction motor with zone shifting space vector modulation (SVM) has been done. It uses a simple phase current re-construction algorithm for three phase induction motor (IM).The phase current re-construction algorithm is done by using information from the current that is from the phases between the inverter and the induction motor. The proposed algorithm is robust and very simple. It uses the AC current to get the stator current for estimating the motor flux and the electromagnetic torque. By evaluating through the torque value and the current the controlling of induction motor is done. The simulation results are also given which supports the direct torque control strategy of the induction motor (IM).

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 .

3-Level Inverter Fed Direct Torque Control of Induction Motor without Using Medium Vectors

This paper proposes the natural extension of classic switching table based direct torque control of induction motor modified for 3-level diode clamped inverter. The proposed method has the advantages of fewer harmonic in the output and low torque ripples. The switching table direct torque control scheme is adopted due to the simplicity of its control algorithm. To demonstrate the performance of proposed multilevel inverter fed direct torque control, the simulations are carried out for constant speed under no load and step change in load. The comparison of the dynamic and steady state performance in terms of torque ripple of the 2-level inverter and 3-level inverters are presented.

Modeling and Direct Torque Control of Induction Motor by using Hybrid Control Technique

In this paper, an adaptive neuro fuzzy interference (ANFIS) based hybrid field oriented speed controlling of an induction motor is proposed. The proposed hybrid field oriented speed controller results attractive performance of induction motor with the potential features of both Artificial Neural network (ANN) and Fuzzy Logic Controller (FLC). In this topology the Artificial Neural Network (ANN) used to estimate the suitable inputs to control the system and Fuzzy Logic Controller used to evaluating the system inputs in terms of logic variables. In the proposed Direct Torque Controller (DTC) scheme the actual motor torque and change in torque is possess through the proposed adaptive neuro fuzzy interference system. Then the speed of the induction motor is controlled by using the controlled electromagnetic torque i.e.,output of the ANFIS controller. The entire proposed system is implemented in MATLAB/SIMULINK environment. And simulation results are also presented to demonstrate the attractive performance of the proposed ANFIS based DTC speed control of the induction motor. And also the comparative steady and dynamic performance of conventional Fuzzy Logic Controller and ANFIS based controller is presented.

Speed and Position Controllers Using Indirect Field-Oriented Control: A Classical Control Approach

Torque control for induction motors under the scheme of indirect field-oriented control (IFOC) considering rotor resistance perturbations is analyzed via linear approximations. Several important characteristics of IFOC are elucidated, leading to the design of linear, robust, and performance-based torque, speed, and position controllers. In particular, the resulting controllers are of a low order, robust to rotor resistance perturbations, and are designed according to classical performance specifications, which is a combination of characteristics that have been historically difficult to achieve. General control design guidelines valid for any induction motor are presented. In addition, the stability and minimum phase conditions of the IFOC torque controller are fully derived for any induction motor. These conditions are of prime importance when designing fixed linear speed or position controllers. A case study for a typical motor, including the design of a series of robust controllers and real-time experimental results, is presented. The proposed approach makes use of well-known classical control methods that allow the results presented here to be further extended using any linear single-input-single-output controller design tool, such as H∞ and quantitative feedback theory.

Bus-Clamping Based Improved Discrete Duty Ratio Control Technology of Direct Torque Control for Induction Motors

One of the disadvantages of traditional direct torque control is high torque ripple, A method of reduce torque ripple was proposed basing bus-clamping and duty ratio control technique in this paper. Firstly, the switch vector table with bus-clamping technology was improved by analyzing the role of zero voltage vector to reduce torque ripple in different sector of voltage. Secondly, on the base of combing the improved bus-clamping direct torque control (BCDTC) and discrete duty ratio control (DDRC), a new switch vector table with discrete duty ratio and bus clamping was designed by analyzing the role of zero voltage vector to reduce torque ripple in different speed range. Finally, simulations are performed to verify the proposed strategies.

A review of direct torque control of induction motors for sustainable reliability and energy efficient drives

The first and the most important step in solving the environmental problems created by cars with internal combustion engines is research and development of electric vehicles. Selection of a proper drive and optimal control strategy of electric vehicles are the major factors to obtain optimal energy management in order to extend the running distance per battery charge. This paper presents a brief review of direct torque control (DTC) of induction motors (IM) as well as its implementation for electric vehicle (EV) applications. First, the basic DTC technique based on hysteresis controllers will be introduced, and then an overview of the major problems in a basic DTC scheme will be presented and explained, as well as some efforts for improving the technique. The main section presents a critical review of DTC for EV applications, taking into consideration the vehicle mechanics and aerodynamics of electric vehicles. The review is very important to provide guidelines and insights for future research and development on the DTC of IM drives for sustainable reliability and energy efficient EV applications.

Fuzzy Logic Based Direct Torque Control of Induction Motor With Space Vector Modulation

The induction motors have wide range of applications for due to its well-known advantages like brushless structures, low costs and robust performances. Over the past years, many kind of control methods are proposed for the induction motors and direct torque control has gained huge importance inside of them due to fast dynamic torque responses and simple control structures. However, the direct torque control method has still some handicaps against the other control methods and most of the important of these handicaps is high torque ripple. This paper suggests a new approach, Fuzzy logic based space vector modulation, on the direct torque controlled induction motors and aim of the approach is to overcome high torque ripple disadvantages of conventional direct torque control. In order to test and compare the proposed direct torque control method with conventional direct torque control method simulations, in Matlab/Simulink,have been carried out in different working conditions. The simulation results showed that a significant improvement in the dynamic torque and speed responses when compared to the conventional direct torque control method.

Study of an Improved Fuzzy Direct Torque Control of Induction Motor

The conventional direct torque control will inevitably produce torque ripple because of its way of flux estimates. For the purpose of handling this problem, a new control strategy was presented in this paper. This strategy combined subdivides control with voltage vector and fuzzy logic control in traditional direct torque control. In this model, the fuzzy logic combined the phase angle of the flux, the flux error and torque error as fuzzy variables and classified these fuzzy variables, in order to optimize the choice of voltage space vector, and the same time the traditional PID regulator is replaced by a fuzzy regulator. Simulation results show that, a great improvement torque responses , a great reduction of torque ripples is achieved and the strategy has a better dynamic and steady performance, especially in low-speed area.

The use of field programmable gate array (FPGA) in direct torque control of induction motor

In this paper, the feasibility of embedding the direct torque control (DTC) of an induction machine into field programmable gate arrays (FPGA) is investigated. DTC of an induction machine is simulated in a MATLAB/Simulink environment using a Xilinx system generator. The resulting design has a flexible and modular structure where the designer can customize the hardware blocks by changing the number of inputs, outputs, and algorithm when it is compared to the designs implemented using classical microcontrollers and digital signal processors. With its flexibility, other control algorithms can easily be programmed and embedded into the FPGA. The above system has been implemented on Xilinx Spartan 3A DSP FPGA controller. Simulation and experimentation have been performed to prove the validity of the proposed methodology.

Direct Torque Control of Induction Motor Based on Neurofuzzy

Direct Torque Control of Induction Motor Based on Neurofuzzy

Improved direct torque control of induction motors using adaptive observer and sliding mode control

Abstract This paper presents the synthesis of an adaptive observer which is used for the improvement of the direct torque control of induction motor drives. The observer detects stator flux components in two-phase stationary reference frame, rotor speed and stator resistance by measure of the stator terminal voltages and currents. The observer is adapted using a simple algorithm which does not imply a high computational load. Stability analysis based on Lyapunov theory is performed in order to guarantee the closed loop stability. Simulation tests under load disturbance and stator resistance variation are provided to evaluate the consistency and performance of the proposed control technique in the low and high speeds.

Field Programmable Gate Array Based Direct Torque Control of Induction Motor Drive

This paper presents a novel design and implementation of Field Programmable Gate Array (FPGA) based Direct Torque Control (DTC) of an Induction Motor Drive fed by Voltage Source Inverter (VSI). The Space Vector Modulation (SVM) based control of VSI results in low steady state torque ripples, current distortions and fast transient response in the motor drive. An FPGA adds flexibility in speed of the control system with its reconfigurable architecture, fast prototype, reduction in execution time delay.

Comparative study of various artificial intelligence approaches applied to direct torque control of induction motor drives

In this paper, three intelligent approaches were proposed, applied to direct torque control (DTC) of induction motor drive to replace conventional hysteresis comparators and selection table, namely fuzzy logic, artificial neural network and adaptive neuro-fuzzy inference system (ANFIS). The simulated results obtained demonstrate the feasibility of the adaptive network-based fuzzy inference system based direct torque control (ANFIS-DTC). Compared with the classical direct torque control, fuzzy logic based direct torque control (FL-DTC), and neural networks based direct torque control (NNDTC), the proposed ANFIS-based scheme optimizes the electromagnetic torque and stator flux ripples, and incurs much shorter execution times and hence the errors caused by control time delays are minimized. The validity of the proposed methods is confirmed by simulation results.

Evolution of local to global minimum torque ripples of direct torque control for induction motor drives

This study discusses the evolution of the local minimum to global minimum torque ripples of the direct torque control of induction motor drives. This study will show that the previous minimum torque ripple design is not the global minimum but a local minimum root-mean-square (RMS) torque ripple. To show this, the study finds the optimal initial torque error, which makes the global minimum torque ripple, and then the related global minimum RMS torque ripple. Moreover, after finding the optimal initial torque error and its related global minimum RMS torque ripple, this study derives the evolution of the initial torque ripple error, under the local minimum RMS torque ripple control strategy. Furthermore, this study also proves that under the local minimum RMS torque ripple control strategy, the local minimum torque ripple will converge to the global minimum value.

The Direct Torque Control of Induction Motors in Hybrid Electric Vehicles Based on the AMEsim

Based on the hybrid vehicle model in AMESim, the real working conditions of an induction motor are analyzed and the drive system’s physical simulation models are built in AMESim. The direct torque control system is designed. And the control system runs by AMESim/Simulink co-simulations. Hence, the feasibility and effectiveness of the proposed design is verified.