Control Of Linear Induction Motor Research Articles

Optimized thrust control of linear induction motors by a compensation approach

This paper describes a solution to the control problems that can be associated with the application of the linear induction motor (LIM) in urban transportation. In order to meet the principle objective of LIM control - the peak thrust tracking - a new compensation technique is presented. The control system has additionally been verified by use of the appropriate finite element field calculations of the LIM and measurements done on the test machine.

Adaptive backstepping sliding mode control for linear induction motor drive

An adaptive backstepping sliding mode controller, which combines both the merits of adaptive backstepping control and sliding mode control, is proposed to control the mover position of a linear induction motor (LIM) drive to compensate for the uncertainties including the friction force. First, the dynamic model of an indirect field-oriented LIM drive is derived. Then, a backstepping sliding mode approach is proposed to compensate the uncertainties which occur in the motion control system. The uncertainties are lumped, and the bound of the lumped uncertainty is necessary in the design of the backstepping sliding mode controller. However, the bound of the lumped uncertainty is difficult to obtain in advance in practical applications. Therefore, an adaptive law is derived to adapt the value of the lumped uncertainty in real-time, and an adaptive backstepping sliding mode control law is proposed. With the adaptive backstepping sliding mode controller, the mover position of the LIM drive possesses the advantages of good transient control performance and robustness to uncertainties for the tracking of periodic reference trajectories. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results.

Intelligent backstepping control for linear induction motor drive

The design and properties of an intelligent backstepping control system for a linear induction motor (LIM) drive to track periodic reference trajectories are studied. First, the dynamic model of a field-oriented control LIM drive is derived. Then a feedback linearisation controller is designed in the sense of the backstepping control technique. To relax the requirement for the bound of lumped uncertainty in the feedback linearisation control law, a recurrent fuzzy neural network (RFNN) uncertainty observer is proposed to estimate the lumped uncertainty in real time. In addition, an online parameter training methodology, derived using the Lyapunov stability theorem and the gradient descent method, is proposed to increase the learning capability of the RFNN. With the proposed intelligent backstepping control system, the mover position of the LIM drive possesses the advantages of good transient control performance and robustness to uncertainties for the tracking of periodic reference trajectories. The effectiveness of the proposed control scheme is verified by both simulated and experimental results.

Adaptive recurrent-neural-network control for linear induction motor

In this study an adaptive recurrent-neural-network controller (ARNNC) is proposed to control a linear induction motor (LIM) servo drive. First, the secondary flux of the LIM is estimated with an adaptive flux observer on the stationary reference frame and the feedback linearization theory is used to decouple the thrust force and the flux amplitude of the LIM. Then, an ARNNC is proposed to control the mover of the LIM for periodic motion. In the proposed controller, the LIM servo drive system is identified by a recurrent-neural-network identifier (RNNI) to provide the sensitivity information of the drive system to an adaptive controller. The backpropagation algorithm is used to train the RNNI on line. Moreover, to guarantee the convergence of identification and tracking errors, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the RNNI and the optimal learning rate of the adaptive controller. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results. Furthermore, the advantages of the proposed control system are indicated in comparison with the sliding mode control system.

Adaptive backstepping control for linear induction motor drive to track periodic references

An adaptive backstepping controller is proposed to control the mover position of a linear induction motor (LIM) drive to track periodic reference inputs in this study. First, the feedback linearisation theory is used to decouple the thrust force and the flux amplitude of the LIM. Then, an integral-proportional (IP) position controller is designed according to the estimated plant model to match the prescribed periodic step-command tracking specifications for the LIM drive. Moreover, a feedforward control is added to the IP control system for the tracking of periodic sinusoidal and triangular reference inputs. Although theoretically the feedforward control can track any time-varying reference, the robust control performance is degenerate when the uncertainties occur in the controlled plant. Therefore, an adaptive backstepping approach is proposed to obtain the robustness for uncertainties. With the proposed adaptive backstepping controller, the mover position of the LIM drive possesses the advantages of good transient control performance and robustness to uncertainties for the tracking of periodic reference inputs. The effectiveness of the proposed control scheme is verified by both the simulated and experimental results.

Nonlinear Control of Linear Induction Motors Using Exact Linearization

Nonlinear Control of Linear Induction Motors Using Exact Linearization

Flux synthesizing linear induction motor with super multiphase switching

AbstractA novel concept of structure and control of linear induction motors (LIMs) called “Flux Synthesizing Linear Induction Motors (FSLIMs),” is proposed where each slot has a conductor carrying an electric current whose amplitude and phase angle are controlled with super multiphase switching devices. It is well known that an LIM has the merits of direct drive and simple structure. However, a conventional LIM has low power factor and energy efficiency. The end effect is one of the significant reasons for the bad characteristics. Strategies against the effect have been limited by conventional three‐phase winding.On the other hand, high‐speed power‐switching devices are available at a reasonable cost. A super multiphase drive enables more freedom for controls with the proposed structure of the FSLIM. Basic characteristics of a tubular test LIM with twelve slots have been measured and calculated to investigate an appropriate flux synthesis. As a result, an appropriate switching scheme which synthesizes sinusoidal distribution of the gap flux density, enables the end‐effects to be suppressed and, consequently, improves the energy efficiency. In addition, basic conditions for the field‐coordinated oriented control of a thrust force are satisfied by keeping the amplitude of the gap flux constant with the flux synthesis.

Flux Synthesizing Linear Induction Motor with Super Multi-Phase Switching.

Authors have proposed a novel concept of structure and control of linear induction motors (LIMs) named “Flux Synthesizing Linear Induction Motors (FSLIMs)”, where each slot has a conductor carrying an electric current whose amplitude and phase angle are controlled with super multi-phase switching devices. It is well-known that a LIM has the merits of direct drive and simple structure. A conventional one has, however, low power factor and energy efficiency; the end-effect is one of the significant reasons for the bad characteristics. Strategies against the effect have been limited by conventional three-phase windings. On the other hand, high-speed power switching devices are available with a reasonable cost. A super multi-phase drive enables more freedom for controls with the proposed structure of the FSLIM. Basic characteristics of a tubular test LIM with twelve slots have been measured and calculated to investigate an appropriate flux synthesis. As results, an appropriate switching scheme, which synthesizes sinusoidal distribution of the gap flux density, enables to suppress the end-effects, and to improve, consequently, the energy efficiency. In addition, basic conditions for the field-coordinateds oriented control of a thrust force are satisfied by keeping the amplitude of a gap flux constant with the flux synthesis.

Thrust control of linear induction motor by detection of magnetic field.

Thrust control of linear induction motor by detection of magnetic field.

A linear induction motor control system for magnetically levitated carrier system

An electromagnetic suspension system has been developed that cuts off electric power-collecting devices from a magnetically levitated vehicle. This system makes it possible to transport materials with no mechanical contact at all between the vehicle and ground facilities. A control system for linear induction motors used in the magnetically levitated carrier system is described. The system was developed to transport materials in an environment which must be kept free from even microscopic dust motes and trivial noise. The linear induction motor control method used for positioning a vehicle at the station is described along with several kinds of switches without any mechanical motion in the ground facilities. A supervisory control system for the magnetically levitated carrier system is also discussed. >

Non-Deadband Reversing Control of Linear Induction Motor

There are numerous applications of Linear Induction Motors (LIM) in industry. More recently, linear positioning servo systems employing LIMs have attracted some interest. This paper describes a method for controlling such motors bydirectionally without deadband. For this purpose, advantage is taken of the double sided construction, which allows separate excitation for each primary. Hence at low speed, two flux waves of opposite direction can be excited, which produce two counteracting forces. At high force levels the mode is shifted to supporting waves, which allows full utilization of the power capability. The LIM is fed through two Thyristor three-phase a.c. controllers. Test results are presented and compared with theoretical considerations. Finally, the plant transfer curve and the control system are briefly analyzed.

Pole-change windings for linear induction motors

Pole-change techniques are potentially valuable for the speed control of linear induction motors. However, they are more difficult to apply in the linear case because of the nonuniform nature of the airgap flux. This precludes the use of parallel paths which are normally employed to reduce the complexity of the switching. The paper describes a new winding connection technique, and shows how it can reduce the number of switch contacts required. The method requires the series connection of alternate coils to form one winding; the remaining coils form a second. Parallel connections are then made between these two windings. An analysis is presented that gives the currents in any general set of serially connected coil groups connected to independent voltage sources. From this, the complete electrical and mechanical performance of the machine can be calculated. The technique can deal with any asymmetric windings having parallel paths, and, while it is ideally suited to the machines under consideration, it has other potential applications. The work is supported by a selection of experimental results that were taken from a pole-change linear motor driving a disc secondary.