Adaptive Full-order Observer Research Articles

Signal Injection in Sensorless PMSM Drives Equipped With Inverter Output Filter

This paper proposes a hybrid observer for sensorless control of permanent-magnet synchronous motor drives equipped with an inverter output <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter. An adaptive full-order observer is augmented with a high-frequency signal injection method at low speeds. The only measured quantities are the inverter phase currents and the dc-link voltage. The effects of the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter on the signal injection are investigated, and it is shown that the filter is not an obstacle to using signal injection methods. The proposed method allows sensorless operation in a wide speed range down to zero speed. Experimental results are given to confirm the effectiveness of the proposed method.

Full-order and reduced-order observer-based synchronization for chaotic systems with unknown disturbances and parameters

The Letter deals with the problem of synchronization of chaotic dynamic system with unknown disturbances and parameters based on observer. First, under some assumptions for drive system, a kind of full-order observer-based synchronization method is summarized. The response system is a robust adaptive full-order observer with adaptation laws for the unknown disturbances and parameters. Second, under the same assumptions, a reduced-order observer-based response system which can synchronize part states of drive system is developed. By choosing a special reduced-order gain matrix, the reduced-order observer-based response system is able to eliminate the influence of the unknown disturbances and parameters directly, so it is unnecessary for one to design the adaptation laws of them. Finally, some numerical simulations for Lorenz chaotic system are design and the simulation results are analyzed in detail.

Sensorless Control of Induction Motors by Reduced Order Observer With MCA EXIN + Based Adaptive Speed Estimation

This paper presents a sensorless technique for high-performance induction machine drives based on neural networks. It proposes a reduced order speed observer where the speed is estimated with a new generalized least-squares technique based on the minor component analysis (MCA) EXIN + neuron. With this regard, the main original aspects of this work are the development of two original choices of the gain matrix of the observer, one of which guarantees the poles of the observer to be fixed on one point of the negative real semi-axis in spite of rotor speed, and the adoption of a completely new speed estimation law based on the MCA EXIN + neuron. The methodology has been verified experimentally on a rotor flux oriented vector controlled drive and has proven to work at very low operating speed at no-load and rated load (down to 3 rad/s corresponding to 28.6 rpm), to have good estimation accuracy both in speed transient and in steady-state and to work correctly at zero-speed, at no-load, and at medium loads. A comparison with the classic full-order adaptive observer under the same working conditions has proven that the proposed observer exhibits a better performance in terms of lowest working speed and zero-speed operation

Sensorless Control of Induction Motor Drives Equipped With Inverter Output Filter

This paper deals with the speed sensorless vector control of an induction motor in a special case where the output voltage of the pulsewidth-modulated inverter is filtered by an inductance-capacitance (LC) filter. The system states are estimated by means of an adaptive full-order observer, and no additional voltage, current, or speed measurements are needed. The rotor speed adaptation is based on the estimation error of the inverter output current. Quasi-steady-state and linearization analyses are used to design an observer that enables a wide operation region, including very low and very high speeds. A torque-maximizing control method is applied in the field-weakening region. Simulation and experimental results show that the performance is comparable to that of a drive without the LC filter

Design strategy of an adaptive full-order observer for speed-sensorless induction-motor Drives-tracking performance and stabilization

Design strategy of both feedback gains and adaptation gains for an adaptive full-order observer is a necessary issue to assure the stability and the tracking performance of the speed estimation in the sensorless drives. In this paper, novel design of feedback gains of the observer is proposed to achieve the stability over the whole operation especially in the low-speed region, including the regenerating mode. Stability improvement using the proposed feedback gains is rigorously proven by the method of Lyapunov. For the adaptation proportional-integral (PI) gains, the ramp response characteristic of the speed estimator is proposed as design guidelines. It is revealed that the integral adaptation gain determines the tracking error of the speed estimator during acceleration/deceleration while the sensitivity to current measurement noises depends on the proportional adaptation gain. It is also pointed out that a suitable corner frequency of the adaptation PI gains is required as a design tradeoff to avoid an oscillation. The validity of all theoretical results is verified by simulation and experiment.

Robust-adaptive-observer design based on /spl gamma/-positive real problem for sensorless induction-motor drives

This paper proposes a design of a robust-adaptive full-order observer based on the /spl gamma/-positive real problem for sensorless induction-motor drives. The adaptive full-order observer is known to become unstable in a major part of the regenerating-mode low-speed operation, and this prevents the sensorless vector controller from operating an induction motor successfully. In this paper, a design of the observer gain for both stable speed identification and robust flux phase estimation and an adaptive scheme for stator resistance identification are proposed. First, the error system of the adaptive full-order observer is reconsidered-requirements of this observer with a speed identifier are described, in which a simple robust observer gain design in the sense of H/sub /spl infin// optimization is not useful in reality. Next, in order to satisfy all the requirements of the robust adaptive observer, the design of the observer gain based on the /spl gamma/-positive real problem and the adaptive scheme for stator resistance are described. Finally, several experimental results show the feasibility and effectiveness of the proposed design.

Sensorless Vector Control of an Induction Motor Fed by a PWM Inverter Through an Output LC Filter

The paper presents a speed sensorless vector control method for an induction motor that is supplied by a PWM inverter through an output LC filter. The system states are estimated by an adaptive full-order observer, and no additional voltage, current or speed measurements are needed. The rotor speed adaptation is based on the estimation error of the inverter output current. Quasi-steady-state analysis is used to illustrate the speed adaptation, and the stability is analyzed using a linearized model. Simulation and experimental results show that it is possible to achieve performance comparable to that of a drive without the LC filter.

適応オブザーバを用いた圧縮機用PMSM位置センサレス駆動システムと調整手法

Position sensor-less vector control with sinusoidal current waveforms is applied to the compressor drive system using an IPMSM for higher efficiency and lower acoustic noise. This paper proposes control methods suitable for compressor drives. For the position estimator, an armature flux based full-order adaptive observer is used. Pole of the observer is selected at a constant real value to simplify the system design. Novel compensation methods using BPF are applied to reduce the cyclic speed change and the current waveform distortion. The inductance measuring method and the starting method are also applied. Principles of the methods are presented as well as experimental results.

A speed-sensorless IM drive with decoupling control and stability analysis of speed estimation

A new sensorless drive based on a decoupling control and an adaptive full-order observer is developed. A modified decoupling control is introduced and integrated with the adaptive observer to reduce the complexity of the whole system. The speed estimation based on adaptive control theory is analyzed and the necessary and sufficient conditions for stability of the speed estimation are analytically derived. It is indicated that the system can be unstable in the low-speed region with regenerative loads. However, assigning an appropriate feedback gain to the adaptive observer can restore the stability and reduce the unstable region. Sensitivity of the sensorless drive against parameter and measurement errors is also qualitatively discussed. Simulation and experimental results are then given to verify the validity of the theoretical results.

A generalized method of controlled voltage source-fed induction motor vector control using the observer theory

Vector control of induction motors is widely used for industrial applications. On-line parameter identification and speed sensorless control are being studied actively. A representative method for these problems is the application of an adaptive full-order observer. The rotor flux for vector control is estimated by a full-order observer and machine parameters, or the rotor speed is determined by an adaptive algorithm. In this paper, a new vector control scheme with parameter identification is proposed. This method is based on the adaptive full-order observer. However, the observed currents which are usually estimated in the voltage model are considered as command currents and the voltage model is used for the current controller. As a result, the proposed system is simpler than the conventional adaptive full-order observer system. Since the proposed system is composed of an induction motor model in a synchronously rotating reference frame, the well-known slip frequency control block is contained. The arrangement of the poles which are related to the torque transfer function is discussed. A linear model is derived taking into account the effects of the change of the stator and rotor resistances. The trajectories of poles and zeros of the torque transfer function are computed and discussed for various system parameters. Identification of stator and rotor resistances is confirmed by simulation using a nonlinear system model. The proposed idea is applied to a speed sensorless system; this system has a similar configuration to those of existing systems under some assumptions. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 66–76, 1997

A Generalized Method of Controlled Voltage Source-Fed Induction Motor Vector Control Using the Observer Theory.

A Vector control of an induction motor is widely used for industrial applications. An on-line parameter identification and the speed sensor-less control are studied actively. The representative method for these problems is an application of the adaptive full order observer. The rotor flux for the vector control is estimated by a full order observer and machine parameters or the rotor speed are determined by an adaptive algorithm. In this paper, a new vector control scheme with parameter identifications is proposed. This method is based on the adaptive full order observer. However, the observed currents which are estimated usually in the voltage model are considered as the commanded currents and the voltage model is used for the current controller instead of the conventional one. As the result, the proposed system is simplified than the conventional adaptive full order observer system. As the proposed system is composed of the induction motor model in a synchronously rotating reference frame, well-known slip frequency control block is contained. An arrangement of the poles which are obtained from the torque transfer function is discussed. A linear model is derived taking into account the effects of the change of the stator and rotor resistances. The trajectories of poles and zeros of the torque transfer function are computed and discussed for various system parameters. An identification of stator and rotor resistances is confirmed by the simulation using a nonlinear system model. The proposed idea is applied to the speed sensor-less system and this system has a similar configuration to the conventional systems under some assumptions.

Adaptive-speed identification scheme for a vector-controlled speed sensorless inverter-induction motor drive

The authors describe a model reference adaptive control system for speed control of the vector-controlled inverter induction motor drive without a speed sensor. The rotor speed is estimated with a full-order adaptive observer and is used as the feedback signal for the vector and speed controls. In order to estimate the speed accurately at low speeds, the motor stator resistance is also identified at the same time to correct the mismatched resistance value used in the observer. The resulting system is verified to be hyperstable. As a result, the drive can be operated in a wide range of speed, and especially, it can be operated stably at the state of zero speed. Experiments also show that the scheme is effective.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Hyperstability of the Full Order Adaptive Observer for Vector Controlled-Induction Motor Drive without Speed-Sensor.

Hyperstability of the Full Order Adaptive Observer for Vector Controlled-Induction Motor Drive without Speed-Sensor.

MRAS Based Speed Sensorless Control Scheme with Stator Resistance Identificating Function for Vector Controlled Induction Motor Drives.

This paper describes a new scheme for the speed sensor-less control of the vector controlled induction motor drive.Based on the model reference adaptive system (MRAS) theory, the rotor speed of the induction machine is estimated with a full order adaptive observer. The estimated speed is then used as the signal for the vector control and the speed control. In order to accurately estimate the speed at lower speed range, the value of the stator resistance is also identified at the same time and then is used to modify the resistance value set in the observer. The resulting system is verified to be hyperstable with Popov's criterion. As a result, this drive can operate stably in a wide range of the speed even at the zero speed. It is also shown theoretically that both speed and resistance of the rotor cannot be identified at the same time, because these two parameters are dependent on each other. Simulation results and experiments also show that the scheme is effective.

An adaptive observer for single-input single-output linear systems with inaccessible input

This paper is concerned with the problem of designing full-order adaptive observers for state estimation andl simultaneous identification of parameters of single-input single-output linear systems with single inaccessible disturbance input. An exponential typo polynomial disturbance model is introduced as an approximation of inaccessible input and necessary and sufficient conditions for the existence of an observer are derived. Then a full-order adaptive observer is based on the Lyapunov design. This design method is a modification of that of Kudva and Narendra (1973). A numerical example is also presented to illustrate the effectiveness of the proposed method.

An adaptive observer for single-input single-output linear systems

A full order adaptive observer is described for observing the state of a single-input single-output observable continuous differential system with unknown parameters. Convergence of the observer states to those of the system is accomplished by directly changing the parameters of the observer using an adaptive law based upon Lyapunov stability theory. Observer eigenvalues may be freely chosen. Some restriction is placed upon the system input in that it must be sufficiently rich in frequencies in order to insure convergence.