Voltage Model Flux Observer Research Articles

A Real-Time Open-Circuit Fault Diagnosis Method Based on Hybrid Model Flux Observer for Voltage Source Inverter Fed Sensorless Vector Controlled Drives

This article presents a open-circuit fault diagnosis method for a sensorless vector control system based on the voltage–current hybrid model flux observer. The error voltage, which is obtained after a PI module, is used as a diagnostic factor. This PI module is designed to correct the deviation between the voltage model flux observer and the current model flux observer. The error voltage is not affected by load and speed variation. First, the activation function is used to separate fault information and normal information, and the feature function is defined to describe the signal feature in healthy and faulty conditions. Second, a second-order moving mean filtering method is proposed to reduce the storage of the error voltage data and increase the timeliness of diagnosis. Finally, the fault is diagnosed and located through logical calculations. Compared with conventional methods, this method features the timeliness of fault diagnosis in a closed-loop system and robustness with respect to speed and load changes. It reduces the storage and operation burden such that it can be easily implanted into the control algorithm as a subroutine. Simulations and experiments show the accuracy and superiority of the proposed fault diagnosis method for voltage source inverter fed sensorless vector controlled drives.

Research on Improved Static Compensation Flux Error MARS Observer Based on SMC

Aiming at the integral drift and saturation problems of the traditional voltage model flux observer, an improved rotor flux observation scheme is proposed. A programmable low-pass filter is used to replace the pure integrator, and the flux error before the filter is corrected. The sliding mode speed controller is used to replace the traditional PI speed controller. The proposed observer can reduce the speed response overshoot of the system at medium and high speed range, reduce the steady-state time, and improve the load capacity and robustness of the system. The simulation results show the effectiveness of the algorithm.

Gopinath Model-Based Voltage Model Flux Observer Design for Field-Oriented Control of Induction Motor

For field-oriented control (FOC) of induction motors, accurate estimation of flux is important. Among the various flux estimation methods, the voltage model flux observer exhibits superior performance in situations where there is detuning of rotor parameters, such as rotor resistance and mutual inductance, because this model is robust to the detuning of these parameters. However, it is difficult to implement the voltage model, which includes pure integration, because of the dc saturation and dc drift problems. A number of methods have been developed to overcome this problem, including the Gopinath model flux observer, which can completely solve these problems. However, this model has a critical weakness in terms of parameter sensitivity in the mid-speed region because of the property of its characteristic function. In this paper, an analysis of parameter sensitivity of existing flux observers is discussed. A method for a voltage model flux observer design based on the Gopinath model is presented. Through an analysis of the characteristic function of the observer, the voltage model is designed. Finally, the operation of the proposed method is proven by simulations and experiments.

Simulation of Induction Machine Drive by Composite Model Flux Observer

 Abstract—This paper presents a robust simulation of direct vector control of induction machine (IM) drive on the rotor flux direction with composite model flux observer. In the indirect vector control of IM, current reference values are used for estimation angle of the rotor flux space vector (ARFSV), however using current reference values instead of current real values can decrease accuracy of ARFSV. In the direct vector control, current real values (current feedback) estimate the ARFSV. ARFSV estimation can be performed by current model flux observer and voltage model flux observer. These observers have their own limitations. The composite model reduces disadvantages of every individual ones. Simulation of composite model is applied to induction machines and obtained results compare to the classical current and voltage models. The composite model approach shows great advantages over those classic ones, a.e. speed control over wide range of motor operation and enough short settling time. All these remarkable advantages support application of composite model in ARFSV.

Learning improvement by using Matlab simulator in advanced electrical machinery laboratory

This paper deals with using simulators such as MATLAB/SIMULINK to work on complicated problems in electrical machines. Simulation of direct vector control of induction machine (IM) drive on the rotor flux direction with composite model flux observer can improve electrical machine learning's of graduate and under graduated students, hi the indirect vector control of IM, current reference values are used for the estimation angle of the rotor flux space vector (ARFSV), however using current reference values instead of current real values can decrease accuracy of ARFSV. hi the direct vector control, current real values (current feedback) estimate ARFSV. The ARFSV estimation can be performed by the current model flux observer and voltage model flux observer. These observers have some restrictions. But The composite model reduces disadvantages of every individual ones. In fact, Simulation of the composite model is applied to induction machines to get results compare to the classical current and voltage models. The interesting point is that the composite model approach shows great advantages over those classic ones, i.e. speed control over the wide range of motor operation with enough short settling time. All these remarkable benefits support the application of composite model in ARFSV. © 2010 Published by Elsevier Ltd.

An Integrated Starter–Alternator and Low-Cost High-Performance Drive for Vehicular Applications

This paper designs and implements an electromechanical propulsion system for a 42-V battery-sourced integrated starter-alternator (ISA) using an indirect-field-oriented (IFO) controller with a speed sensor on the shaft of the machine. The design aspects of the ISA energy conversion system are discussed, with emphasis on the motor selection and comparison of various candidate machines, power electronics, motor controller development and its integration with the engine controller, and a strategy for charging and discharging the energy source. A boost converter powered by the 42-V battery charges three 1-F ultracapacitors to 300 V, thus running the motor drive system at 300 V. The designed 300-V motor drive system is compared with the 42-V drive system directly powered by the 42-V battery. To improve the performance of the propulsion system, two modifications are proposed in this paper. First, terminal-quantities-based accurate voltage and current model flux observers (CMFOs) are designed, which can be used for any off-the-shelf machine. Second, a current model flux-observer-based sensorless controller is presented, which eliminates the need for the speed sensor on the rotor shaft, thus reducing the cost as well as the maintenance of the drive system. The proposed terminal-quantities-based flux observers and sensorless controller form the core of direct and IFO controllers commonly used in any alternative energy vehicular application including the ISA. The designed voltage model flux observer is insensitive to the stator resistance, and the CMFO is insensitive to the rotor resistance and speed, thus overcoming the long-standing problems in the area of flux observer design. The experimental results obtained while driving the vehicle are presented to demonstrate the effectiveness of the prototype ISA and to investigate its performance requirements as a sensorless drive system. Finally, the performance of the proposed flux observers and sensorless controller is evaluated through experimental results on a prototype induction machine to evaluate their potential for implementing a sensorless ISA drive system.

Elimination of the Stator Resistance Sensitivity and Voltage Sensor Requirement Problems for DFO Control of an Induction Machine

This paper focuses on a method for achieving robust direct field orientation control of an induction machine using a closed-loop voltage model flux observer that is insensitive to stator resistance variation and does not require voltage signal information, thereby eliminating the need for a voltage sensor. In contrast, the conventional voltage model observer topology requires voltage sensors and is highly sensitive to stator resistance variation, especially at low speed. The closed-loop sliding-mode voltage model flux observer presented here is based on current estimation error including a sliding-mode function which is a derivative of the stator flux. The newly designed sliding-mode function will not only drive the estimated current to the measured one, it will also directly give the estimation results for the terms (stator flux) replaced by the sliding-mode function. The constructed observer and chosen sliding-mode function also do not require information about parameters contained in the terms replaced by the sliding-mode function, i.e., voltage signal and stator resistance. The observer stability is verified in the paper. Simulation and experimental results are also used to illustrate features of the proposed observer.

Design of voltage model flux observer

The voltage model flux observer can accurately estimate the stator flux when operating at high speed. However, at low speed this estimation is highly sensitive to the stator resistance variation. Also the observer needs voltage sensors for actual voltage measurements and becomes less accurate if command voltages are used, especially beyond the linear modulation region, where the command voltages are no longer equal to the actual ones. These problems are addressed through the design of a closed-loop voltage model flux observer that is completely insensitive to stator resistance variation, and thus it can work at high as well as low speed. The proposed observer also does not require any voltage signal information, either command or measured one, thus making it more accurate even beyond the linear modulation region without adding any voltage sensors. The observer stability has been verified. Simulation and experimental results are presented to validate the proposed algorithm.