Adaptive robust fast control for induction motors

A new induction motor position controller that exhibits fast response and robustness is proposed. The control strategy is based on the well-known linear quadratic regulator design principle. By adaptively adjusting a penalty parameter, it is shown that the control strategy enables the induction motor system to exhibit fast convergence. Meanwhile, since the sliding mode will occur in the transient process, the fast control inherits the robustness in matched uncertainties of the sliding-mode control. In addition, to alleviate the chattering effect of the switching control signal, a low-pass filter is used to smooth the control and its design is integrated with the switching control design. The performance of the proposed control strategy is verified by experimental results     

Motion control with induction motors

Induction motors (IM) provide a very wide speed range, mechanically robust and relatively low cost motion control option. An up-to-date summary of the status of induction motor motion control technology is the subject of this paper. The topics which this paper includes are as follows: basic motion control system requirements; field orientation instantaneous torque control principles for induction motors (FO-IM); current regulators for induction motor motion control; flux and torque regulators for induction motor motion control; self commissioning and continuous self-tuning for field orientation. Technology advances based on modern control and estimation theory have the potential to further enhance the capability of this important class of servo drive systems     

Sensorless sliding-mode control of induction motors

This paper develops the ideas of speed- and flux-sensorless sliding-mode control for an induction motor illustrated in previous work by one of the authors. A sliding-mode observer/controller is proposed in this paper. The convergence of the nonlinear time-varying observer along with the asymptotic stability of the controller is analyzed. Pulsewidth modulation implementation using sliding-mode concepts is also discussed. Major attention is paid to torque control, and then the developed approach is utilized for speed control. Computer simulations and experiments have been carried out to test the proposed estimation and control algorithm. The experimental results demonstrated high efficiency of the proposed estimation and control method.     

Passivity-based control of saturated induction motors

A passivity-based controller, which takes into account saturation of the magnetic material in the main flux path of the induction motor, is developed to provide close tracking of time-varying speed and flux trajectories in the high magnetic saturation regions. The proposed passivity based controller is experimentally verified. Also, a comparison between the controllers based on the saturated and nonsaturated magnetics is presented to demonstrate the benefit of the controller based on the saturated magnetics     

Vector control strategies for single-phase induction motor drive systems

This paper discusses vector control strategies for single-phase motor drive systems operating with two windings. A model is proposed and used to derive control laws for single-phase motor drive systems. Such model is also employed to introduce the double-sequence controller. Simulation and experimental results are provided to illustrate the operation of the proposed drive systems.     

Field-oriented control of induction motors using neural-networkdecouplers

This paper presents a novel approach to the field-oriented control (FOC) of induction motor drives. It discusses the introduction of artificial neural networks (ANNs) for decoupling control of induction motors using FOC principles. Two ANNs are presented for direct and indirect FOC applications. The first performs an estimation of the stator flux for direct field orientation, and the second is trained to map the nonlinear behavior of a rotor-flux decoupling controller. A decoupling controller and flux estimator were implemented upon these ANNs using the MATLAB/SIMULINK neural-network toolbox. The data for training are obtained from a computer simulation of the system and experimental measurements. The methodology used to train the networks with the backpropagation learning process is presented. Simulation results reveal some very interesting features and show that the networks have good potential for use as an alternative to the conventional field-oriented decoupling control of induction motors     

Minimum-time minimum-loss speed control of induction motors underfield-oriented control

A new minimum-time minimum-loss speed control algorithm for induction motors is suggested to obtain high performance, as well as high efficiency, under field-oriented control with practical constraints on voltage and current. This algorithm utilizes a two-stage control. In the transient stage, a maximum torque control algorithm is utilized to get the minimum-time response. In the steady state, a minimum-loss control algorithm is applied to improve the efficiency. Simulation studies show the performance of the proposed minimum-time minimum-loss control algorithm under field-oriented control     

Rotor-flux-oriented control of a single-phase induction motor drive

This paper investigates the vector control of a single-phase induction motor drive to implement low-cost systems for low-power applications. The static power converter side is implemented using a single-phase rectifier cascaded with a four-switch inverter. The vector control is based upon field orientation concepts that have been adapted for this type of machine. Simulation and experimental results are provided to illustrate the system operation     

Dual-inverter control strategy for high-speed operation of EV induction motors

An integrated starter/alternator (ISA) is normally designed to have high pole structure (10-14 poles) for high starting torque. However, its back electromotive force (EMF) at the peak revolutions per minute should be less than its battery voltage for the power flow control. For example, the back-EMF of a 12-pole ISA should be 42 V at 6000 r/min. These types of conflicting requirements lead to a nonclassical motor design that has extremely large field-weakening range (8:1/spl sim/10:1). In this paper, we are considering the use of an induction machine instead of a permanent synchronous machine. As an idea for solving the voltage limit problem, two inverters are utilized with an objective of sharing the required voltage. The secondary inverter only takes care of the reactive voltage component that grows very fast in high-speed operation. Therefore, an extra voltage source is not required for the secondary inverter. Only a capacitor bank suffices for the secondary inverter.     

Sensorless control of induction motors by artificial neuralnetworks

In this letter, we propose a voltage-source inverter control working in the open loop of an induction motor measuring the stator current and using an artificial neural network. This technique has the mission to estimate the speed and torque of the rotor without using sensors. With this, a simple and cheap method of control is obtained, with as much precision and robustness as other more complex ones     

Unified sensorless vector control of synchronous and induction motors

In this paper, a unified theory for sensorless flux estimation and vector control of induction motors and nonsalient permanent-magnet synchronous motors (PMSMs) is developed. It is shown that an estimator and vector controller for one of the motor types can also be applied to the other, with only minor modifications necessary. Two candidate estimators are considered: a variant of the well-known "voltage model" (VM) and a phase-locked-loop-type speed and position estimator. These are applied to both motor types, and evaluated experimentally. For the nonsalient PMSM, an important result is that synchronization can be guaranteed from any initial rotor position.     

FOC and DTC: two viable schemes for induction motors torque control

Field-oriented control and direct torque control are becoming the industrial standards for induction motors torque control. This paper is aimed at giving a contribution for a detailed comparison between the two control techniques, emphasizing advantages and disadvantages. The performance of the two control schemes is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command. The analysis has been carried out on the basis of the results obtained by numerical simulations, where secondary effects introduced by hardware implementation are not present.     

Comments on "Passivity-based control of saturated induction motors"

The authors comment on the paper by L.U. Gokdere et al. (see ibid., vol. 48, p.870-2, 2001). A review of the experimental evidence shows that passivity-based control of saturated induction motors does not provide superior performance over input-ouput linearization. Higher tracking errors can be observed and traced to the open-loop nature of the flux controller. In contrast, input-output linearization controllers achieve close tracking of flux, speed, and position references for the most demanding trajectories.     

Motion control of rigid robots driven by current-fed induction motors

The problem of controlling a rigid manipulator driven by induction motors operating in the current-command mode to follow a desired trajectory is considered in this paper. Based on a fourth-order reduced model of an induction motor, a current controller is proposed using only measurements of link positions and velocities as well as stator currents of induction motors. The rotor flux is estimated through a closed-loop observer. Provided that the flux observer is properly initialized, this controller is singularity-free and ensures the global exponential tracking to the desired trajectory. Simulations are presented to illustrate the performance of this controller.     

Analysis of phase-controlled converters for induction motors

A phase-controlled converter for induction motors is analyzed, using a representation of semiconductor switching devices as two-state resistances. The steady state of symmetrically controlled converters (when the states of the semiconductor switching devices change periodically) is considered, and symmetrical components of the motor phase currents are used. This allows classical equivalent circuits of the induction motor to be used. As a result of the analysis the Fourier spectrum of the motor phase currents and electromagnetic torque is determined. An example that shows the application of the relations presented here is given     

A vector control scheme for EV induction motors with a series ironloss model

Electric vehicle (EV) motors are characterized by their low inductance and high current density, so that they run at high speed and produce a high starting torque. Due to the low inductance coil design, the current ripple caused by pulsewidth modulation (PWM) switching makes a significant amount of eddy-current loss and hysteresis loss, especially in high-speed operation. If one simply neglects the iron loss, the overall vector controller is detuned, resulting in an error in the torque control. The iron loss is modeled, in general, by a parallel resistor R_M to the magnetizing inductor L_M. The authors propose a series R-L model that accounts for the effects of the iron loss. A major advantage of the series model is that it does not increase the number of state variables in developing a vector control. In this paper, they derive a rotor-flux-oriented flux error, orientation angle error, and torque error caused by iron loss. Finally, they demonstrate the effectiveness of the proposed control method through computer simulation and experimental results     

Adaptive decentralized control of robot manipulators driven by current-fed induction motors

In this paper, an adaptive decentralized control scheme with a rotor-flux observer is proposed for the tracking control of robot manipulators actuated by current-fed induction motors. To cope with all parametric uncertainties in the electromechanical systems, an adaptive law is designed so that all the signals of closed-loop systems are bounded, and the tracking errors in position, velocity and rotor fluxes converge to a residual set.     

基于模糊控制器的异步电机直接转矩控制

为降低传统直接转矩控制(DTC)的转矩脉动,提出了一种基于模糊空间矢量调制的异步电机直接转矩控制方案,该方案将模糊控制技术和空间调制(SVM)技术相结合。模糊控制器的两个输入为转矩误差和误差的变化率,输出为电压矢量的转矩控制分量。为提高控制系统的鲁棒性,采用了基于反电动势的模型参考自适应(MRAS)的无速度估算方法对转子转速进行估算。仿真结果验证了该方案的可行性和有效性。     

An improved stator flux estimation for speed sensorless stator fluxorientation control of induction motors

This paper proposes a programmable low pass filter (LPF) to estimate stator flux for speed sensorless stator flux orientation control of induction motors. The programmable LPF is developed to solve the DC drift problem associated with a pure integrator and a LPF. The pole of the programmable LPF is located far from the origin in order to decrease the time constant with the increasing speed. In addition, the programmable LPF has a phase/gain compensator to estimate exactly stator flux in a wide speed range. Consequently, the drift problem is much improved and the stator flux is exactly estimated in the wide speed range. The validity of the proposed programmable LPF is verified by speed sensorless vector control of a 2.2 kW three-phase induction motor