Parameters Variation to Estimate Performance Characteristics of 3-Phase Asynchronous Motor

On drilling rigs equipped with an independent and mechanically driven rotary table, rotary speed is often found to be torque sensitive. This paper describes an automatic control system designed for use on these mechanical rigs to compensate for rotary speed variation with load. Transfer functions for a loaded rotary table were developed using basic closed-loop control theory, and the components of the resulting control system are discussed. An analysis of the proposed system demonstrating optimum response and stability is given. The design objective of maximum dampening of speed variations without oscillation is demonstrated by simulation. From this development, it has been concluded that a relatively simple control loop is sufficient for automating a rotary drive engine by positioning a pneumatic throttle. Further, when the control loop is used, the average rotary table speed becomes independent of pipe torque. The system has proved to be reliable under field operating conditions. Introduction In applying technology to a drilling operation, rotary speed is of prime importance. For example, the "d" exponent, formation drillability, roller bit bearing and tooth wear as well as many other drilling relationships are functions of rotary speed.l-3 To use rotary speed in any of these equations, it must be measurable and fairly constant over the time interval of interest. The conventional method of controlling rotary speed on a rig, with an independent and mechanically driven rotary table is through the use of a pneumatic regulator at the drawworks. The regulator supplies air pressure to a diaphragm which mechanically positions the engine throttle. This method does not provide a constant rotary speed. Variations in rotary torque present a constantly changing load to the engine. Consequently, if the throttle is held constant, the angular speed of the rotary table will vary considerably. This effect is illustrated in Fig. 1, which is an actual recording of torque and rotary speed on a rig where the rotary speed was controlled in the manner described above. Note that the average value of rotary speed varied inversely with torque until the driller finally changed the throttle setting to bring the rotary speed back to its initial value. In order to keep rotary speed constant, the throttle would have to be continuously repositioned to compensate for the load changes. An automatic closed-loop control system can perform this operation.

A large number of permanent magnet synchronous motors (PMSMs) are used to drive coal conveyer belts in coal enterprises. Sensorless energy conservation control has important economic value for these enterprises. The key problem of sensorless energy conservation control for PMSMs is how to decompose the stator current through estimating the rotor position and speed accurately. Then a double closed loop control for stator current and speed is formed to make the stator current drive the motor as an entire torque current. In this paper, the proposed startup estimation algorithm can utilize the current model of PMSM as reference model to estimate the rotor speed and position in the startup stages. It is not dependent on the back electromotive force (EMF) which is used by the general estimation algorithm. However, the resistance will change with the temperature shift of stator windings, and these changes will cause the reference current model to be inaccurate and influence the rotor speed and position estimation precision. Thus, startup estimation algorithm switches to the proposed operation estimation algorithm which is based on the robust sliding mode theory and is not dependent on the motor parameters. The advantages of startup estimation algorithm and operation estimation algorithm are combined to form a hybrid observer. This hybrid observer realizes the accurate estimation of the rotor speed and position from start-up to operation. The stator current is precisely decomposed. The excitation current is controlled to 0. Meanwhile, the double closed-loop control of current and speed is achieved. The stator current is as entire torque current to drive motor. The closed-loop control, which is based on the proposed rotor position and speed estimation algorithm, achieve the most efficient conversion of electrical energy.

Integration of in-wheel motor sensorless systems and hierarchical direct yaw moment control for distributed drive electric vehicles

The control scheme of parallel drive system of the dual Switched Reluctance machines based on fuzzy logic control is proposed and verified for the first time. The system consists of main machine, subordinate machine, main power converter, subordinate power converters, main controller and subordinate controller. The main controller is used for closed-loop rotor speed control of main machine, with the subordinate controller for synchronized rotor speed and loads equilibrium distribution between main machine and subordinate machine. The fuzzy logic control algorithm with PWM control is given. A nonlinear simulation model of the system founded on MATLAB is also given. The simulated results and tested results on the prototype with three given rotor speeds and two different loads show that when compared with the system with sliding mode control adopted, the phase current peak value is smaller, the rotor speed static error is also smaller, the rotor speed response synchronization at starting between main machine and subordinate machine is well.

The paper presented a control scheme for parallel drive system of double Switched Reluctance machines. The sliding mode control algorithm is adopted in the main controller for closed-loop rotor speed control of main machine. The sliding mode control algorithm is also adopted in the subordinate controller for synchronized rotor speed and loads equilibrium distribution between main machine and subordinate machine. The given rotor speed and the actual rotor speed of the main machine are the input parameters of the main VSS controller. The duty ratio of pulse width modulation signal of the main VSS controller can be gained by the sliding mode control algorithm. The actual rotor speed of the main machine, the actual rotor speed of the subordinate machine, the average values of DC bus supply current for main power converter, and the average values of DC bus supply current for subordinate power converter are the input parameters of the subordinate VSS controller. The increment of the duty ratio of pulse width modulation signal of the subordinate VSS controller can be gained by the VSS control algorithm. The nonlinear simulation results of the system based on MATLAB-Simulink show that the advanced scheme is satisfied with synchronized rotor speed and loads equilibrium distribution between main machine and subordinate machine.

With this automatic control system for use on rigs equipped with a mechanically driven rotary table, it is possible to eliminate rotary speed variation caused by torque in the drill pipe. When closed-loop control is used, low-frequency variations in rotary speed can be completely eliminated, and high-frequency variations can be significantly damped, depending upon the power available. Introduction In applying technology to a drilling operation, rotary speed is of prime importance. For example, the d exponent, formation drillability, roller-bit-bearing and tooth wear, as well as many other drilling relationships are functions of rotary speed. If rotary speed is to be used in any equations related to these, it must be measurable and fairly constant over the time interval of interest. The conventional method of controlling rotary speed on a rig with an independent and mechanically driven rotary table is to use a pneumatic regulator at the drawworks. The regulator pneumatic regulator at the drawworks. The regulator supplies air pressure to a diaphragm, which mechanically positions the engine throttle. This method does not positions the engine throttle. This method does not provide a constant rotary speed. Variations in rotary provide a constant rotary speed. Variations in rotary torque present a constantly changing load to the engine. Consequently, if the throttle is held constant, the angular speed of the rotary table will vary considerably. This effect is illustrated in Fig. 1 which is an actual recording of torque and rotary speed on a rig where the rotary speed was controlled in the manner described above. Note that the average value of rotary speed varied inversely with torque until the driller finally changed the throttle setting to bring the rotary speed back to its initial value. To keep rotary speed constant, the throttle would have to be continuously repositioned to compensate for the load changes. An automatic closed-loop control system can perform this operation. Such a control system has been designed and successfully used on several rigs to control rotary speed remotely. Our purpose is to describe that closed-loop control system and the results of simulation and field testing. Basic Control Theory A closed-loop control system is one that controls a variable by measuring it, comparing it with a desired value and correcting it if it is not equal to the desired value. It follows then that the system must perform two equally important functions: measurement and control. A simple illustration of this would be a man controlling the temperature of an oven by looking at a thermometer, noting that it reads lower than the desired temperature. and throwing a switch that causes an increase in heat flow to the oven. In the system to be discussed here the control is automatic. There are many theories on how to study the performance of closed-loop control systems. The most performance of closed-loop control systems. The most common method, and the one that will be discussed here, uses simplified block diagrams and mathematical models. Terms that will be used throughout the paper are defined here: Input A signal in engineering units, going into the control loop or any of its components. Output A signal in engineering units, coming outof the control loop or any of its components. JPT p. 1305

This paper describes a new sensorless vector control strategy for induction motor which can meet the requirements of constant large load torque, based on the comparative study of two observation methods for flux linkage, which are high-frequency signal injection method (HFSIM) and full order flux observer. In the low speed region, a high-frequency signal is injected, which is independent of the motor parameters. The rotor speed is identified by extracting the high frequency current. In the higher speed region, the rotor speed is obtained through full order flux observer to prevent the high-frequency torque ripple caused by HFSIM. An appropriate state switcher is proposed, in order to ensure smooth transition as the speed rises, as well as to ensure the accurate estimation of the rotor flux orientation angle within the whole speed range. The overall control strategy can output constant torque and satisfy heavily loaded condition. The experimental motor control test proves the correctness and effectiveness of the proposed strategy.

Doubly fed induction generator (DFIG) needs to get adapted to situations like rapid change in wind speed and sudden requirement for grid disturbances to meet modern grid rules. The paper explains the design of controllers for MPPT algorithm for the turbine, DFIG converters, and sensorless rotor speed estimation. These intelligent controllers are used to maintain equilibrium in rotor speed, generator torque, and stator and rotor voltages. They are also designed to meet desired reference real and reactive power during the turbulences like sudden change in reactive power or voltage with concurrently changing wind speed. The turbine blade angle changes with variations in wind speed and direction of wind flow and improves the coefficient of power extracted from turbine using MPPT algorithm. Rotor side converter (RSC) helps to achieve optimal real and reactive power from generator, which keeps rotor to rotate at optimal speed and to vary current flow from rotor and stator terminals. For tracking reactive power demand from grid and in maintaining synchronism when grid voltage changes due to fault at a very faster and stable way Grid side converter (GSC) is helpful. Rotor speed is estimated using stator and rotor flux estimation algorithm. Parameters like stator and rotor voltage, current, real, reactive power, rotor speed, and electromagnetic torque are studied using MATLAB simulation. The performance of DFIG is compared when there is in wind speed change only; alter in reactive power and variation in grid voltage individually along with variation in wind speed.

This aim of this paper is to design controller for Doubly Fed Induction Generator (DFIG) converters and MPPT for turbine and a sensor-less rotor speed estimation to maintain equilibrium in rotor speed, generator torque, and stator and rotor voltages. It is also aimed to meet desired reference real and reactive power during the turbulences like sudden change in reactive power or voltage with concurrently changing wind speed. The turbine blade angle changes with variations in wind speed and direction of wind flow and improves the coefficient of power extracted from turbine using MPPT. Rotor side converter (RSC) helps to achieve optimal real and reactive power from generator, which keeps rotor to rotate at optimal speed and to vary current flow from rotor and stator terminals. Rotor speed is estimated using stator and rotor flux estimation algorithm. Parameters like tip speed ratio; coefficient of power, stator and rotor voltage, current, real, reactive power; rotor speed and electromagnetic torque are studied using MATLAB simulation. The performance of DFIG is compared when there is in wind speed change only; alter in reactive power and variation in grid voltage individually along with variation in wind speed.

This paper proposes a short-term frequency-response scheme of a doubly-fed induction generator (DFIG)-based wind turbine generator (WTG) for improving rotor speed recovery and frequency nadir. In the energy-releasing period, to improve the frequency nadir and rotor speed convergence by releasing a large amount of kinetic energy stored in the rotating masses in a DFIG-based WTG, the power reference is increased up to the torque limit referred to the power and reduces along with it for a predefined period which is determined based on the occurrence time of the frequency nadir in a power grid. Then, the reference decreases so that the rotor speed is forced to be converged to the preset value in the stable operating region of the rotor speed. In the energy-absorbing period, to quickly recover the rotor speed, the reference smoothly decreases with the rotor speed and time during a predefined period until it intersects with the maximum power point tracking curve. The simulation results demonstrate that the proposed scheme successfully achieves rapid frequency stabilization with the improved frequency nadir under various wind conditions based on the IEEE 14-bus system.

This paper studies the effects of increased temperature on the performance of the three phase induction motor. An electrical, mechanical, and thermal model of an induction motor is used to study the change of the motor parameters. The proposed model is developed using Matlab-Simulink. The experimental work is implemented in order to investigate the effect of temperature rise on the induction machine. Simulation and experimental results were obtained to monitor the effects of increased temperature on the stator resistance, stator current, rotor speed, stator flux and motor torque at different loads.

This paper studies the effect of increased temperature on the performance of the three phase induction motor. An electrical, mechanical, and thermal model of an induction motor is used to study the change of the motor parameters. The proposed model is developed using Matlab-Simulink. The experimental work is implemented in order to investigate the effect of temperature rise on the induction machine. Simulation and experimental results were obtained to monitor the effect of increased temperature on the stator resistance, stator current, rotor speed, stator flux and motor torque at different loads.

Speed sensorless vector controlled induction motor drives are the standard choice in many industrial applications, but this can hardly control torque and rotor speed at low speed. Recently, a method based on high‐frequency signal injection has been studied. This paper presents a method for suppressing the effects of the saturation saliency by using a high‐pass filter, and a new approach to estimate the rotor speed. The effectiveness of these methods is demonstrated through experimental results showing both good suppression of saturation harmonics and good sensorless speed control at low speed. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(1): 41–49, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20847

This paper describes the importance and applications of multi-phase electrical machines. The components of the five-phase electrical drive were analyzed. Due to the MATLAB/Simulink model, the simulation of the electrical drive under normal mode and faulty conditions was carried out to analyze the performance of the five-phase induction motor. Several cases of faulty conditions caused by unbalanced voltage system were considered and the simulation results of stator phase’s currents, rotor speed and electromagnetic torque were analyzed in more detail. The importance of this study is related to the various applications of multi-phase machines in different fields of industry and a lot of scientific researches based on this topic. Simulation results have shown that the five-phase machine is very reliable and it has better fault tolerance due to its slightly affected by the unbalanced voltage system.

Removed.