Rodrigo Padilha Vieira

Discrete-time sliding mode approach for speed estimation of symmetrical and asymmetrical induction machines

This paper presents and analysis a rotor speed estimator for symmetrical and asymmetrical induction machines. The proposed scheme is based on discrete-time formulation of the sliding mode observer. The method is suitable to close-loop sensorless control of induction machines. The stability and parameter convergence of the proposed method are analyzed by using discrete-time likelihood Lyapunov. Experimental results based on DSP platform (TMS320F2812) are presented and they demonstrate the good performance of the proposed sensorless control scheme for symmetrical and asymmetrical induction motor drives.

Decoupling and sensorless vector control scheme for single-phase induction motor drives

Vector control has improved the performance and energy efficiency in SPIM drives. However, high current and torque pulsations are produced by winding asymmetry of SPIM. This paper proposes a decoupling scheme to reduce the current and torque pulsations and improve the performance of vector control. A stator current observer is used to estimate the coupling signals, which are compensated by control law. This method is an alternative to improve the performance of single-phase induction motor used in hermetic refrigeration systems. The thermal efficiency of refrigeration system can be improved by the variable speed operation and the advantages of robustness and low-cost of single-phase induction motor can be maintained.

Discrete-time sliding mode speed observer for induction machine drives

This paper addresses the rotor speed estimation problem of induction machine drives. A scheme based on discrete-time formulation of the Sliding Mode Observer is proposed and analyzed. The method is suitable to close-loop sensorless control of induction machines. The stability analysis and parameter convergence of the proposed method is presented. Simulation and experimental results based on DSP platform (TMS320F2812) demonstrate the good performance of the proposed sensorless control scheme.

Linear Matrix Inequality Based Synthesis Of Pi Controllers For Pmsm With Uncertain Parameters

This paper addresses the design of robust PI controllers for permanent magnet synchronous motors in terms of a linear matrix inequality based problem. A polytopic model of the plant is obtained and validated for the motor uncertain parameters belonging to intervals. The design procedure proposed here encompasses: i. suitable plant uncertainties inclusion and the use of practical design control constraints; ii. robust PI computation based on linear matrix inequalities with a very fast solution; iii. simulation analyses; and iv. experimental evaluations. The robust PI controller can produce superior speed regulation than a PI controller designed only for the nominal parameters, including better disturbance rejection and H∞ performance. Experimental results confirm the viability of the proposal, which can be seen as an efficient alternative to trade off performance and robustness for PI controllers in this application.

Feedback linearization control with sliding mode speed observer for three-phase induction machines

This paper addresses the problem of controlling a three-phase induction motor without speed measurements. A nonlinear feedback linearization control was designed for a fifth order induction motor model including electrical and mechanical dynamics. The proposed control scheme, which is an indirect field oriented control technique (IFOC) based on feedback linearization control (FLC), is made up of flux-speed controllers. It is inserted on these controllers additional terms designed according discrete time Lyapunov functions to ensure the flux alignment. In order to provide an estimated rotor speed for the control system, it is used a slide mode observer algorithm. Some experimental results with TMS 320F2812 DSP are provided to verify the proposed system performance in a low speed conditions.

Electrical disturbance compensation algorithm applied to three-phase induction motors

One of the ways to control the dynamic of an induction motor is using Field Oriented Control (FOC) or Vector Control. But in this case we can remark electrical disturbance represented by coupling between direct and quadrature currents of induction motor and parameters uncertainties. This disturbance degradate the control law when the rotor speed grows. In this paper we proposed a algorithm to improve the performance of vector control. The algorithm is based on Lyapunovs Direct Method and it is used to estimate this disturbance and eliminated him. Simulation results are shown to validate the proposed technical.

Discrete-time sliding mode rotor flux and rotor speed observer for induction machine drives

This paper presents the development of discrete-time sliding mode rotor speed and rotor flux observer applied to induction machine drives. The conditions for the discrete-time sliding hyperplane existence are discussed. The sliding hyperplane are formed by the stator currents estimation errors and by the observed rotor fluxes. Simulation and experimental results using DSP TMS320F2812 are presented aiming to verify the effectiveness of the proposed scheme.

Electrical Parameter Identification of Single-Phase Induction Motor by RLS Algorithm

Controlled induction motor drives have been employed on several appliances in the last decades. Commonly, the control schemes are based on the FOC and sensorless techniques. These methods are mainly applied to three-phase induction machine drives, and a wide number of papers, such as [5, 9, 10, 15, 19, 23, 26] have described such drives. On the other hand, for several years the SPIM has been used in residential appliances, mainly in low power and low cost applications such as in freezers and air conditioning, consuming extensive rate of electrical energy generated in the world. In most of these applications, the SPIM operates at fixed speed and is supplied directly from source grid. However, in the last few years several works have illustrated that the operation with variable speed can enhance the process efficiency achieved by the SPIM ([1, 4, 8, 31]). Furthermore, some other studies have presented high performance drives for SPIM using vector control and sensorless techniques, such as is presented in [7, 12, 18, 24] and [29]. However, these schemes applied on single-phase and three-phase induction motor drives need an accurate knowledge of all electrical parameters machine to have a good performance.

Feedback Linearization of Speed-Sensorless Induction Motor Control with Torque Compensation

This paper addresses the problem of controlling a three-phase induction motor without speed measurements and with torque compensation. A nonlinear feedback linearization control was designed for a fifth order induction motor model including electrical and mechanical dynamics. The proposed control scheme, which is an indirect field oriented control technique (IFOC) based on feedback linearization control (FLC), is made up of flux-speed controllers. In order to provide an estimated rotor speed for the control system, a model reference adaptive system (MRAS) algorithm based on reactive power was applied. This estimation passes through a Kalman filter, which is also used for the torque estimation. Some experimental results with TMS 320F2812 DSP are provided to verify the proposed system performance in a low speed over load variation conditions.

Optimal Discrete-Time Complete Order State Observer Applied to Asynchronous Machine Drive Systems

In this work, the state observer problem of multivariable systems, using optimal discrete-time complete order state observer applied to high performance Asynchronous Machine drive systems is considered. Due to the computational time to discretize the model, the procedure is carried off-line, resulting in a discrete model with only algebraic relations. The feedback matrix (gains) is also calculated off-line, using an optimal control law. The gains are calculated for some machine frequencies, resulting in some matrix gains operating in scheduled form (gain scheduling). Note that multiple gain matrix solutions exist. This variety can be used to provide robust properties for the closed loop system and should make the system insensitive to perturbations.