Popov's Hyperstability Criterion Research Articles

Transient and steady‐state study of a speed sensorless IPMSM drive with an advanced integrator‐based stator flux estimator

In this paper, an advanced integrator is proposed for the estimation of stator flux in a direct torque control (DTC) drive. A two-level lookup table-based direct torque-controlled interior permanent magnet synchronous motor (IPMSM) drive is implemented. DTC has the inherent disadvantage of DC drift and saturation in stator flux estimation due to a pure integrator. In the proposed work, a different approach to estimate stator flux is reported overcoming the constraints of a pure integrator in DTC. An advanced integrator with an adaptive controller is implemented to determine the stator flux and enrich the performance of the drive. A comparison of transient and steady-state analysis is carried out when IPMSM is fed by a low-pass filter-based DTC and proposed stator flux estimator-based DTC. To make the system mechanically robust, stator current-based model reference adaptive control is executed to estimate the motor speed. A mathematical derivation for the stability study of the adaptation mechanism is carried out using Popov's hyperstability criteria. The proposed algorithm is implemented in the MATLAB/Simulink environment and the soundness of the proposed work is presented by simulation results. Moreover, the experimental analysis using dSPACE1104 justifies the simulation results of the proposed system.

Implementation of reactive power‐based MRAS for sensorless speed control of brushless doubly fed reluctance motor drive

The present work introduces the concept of classical reactive power (Q)-based model reference adaptive system (MRAS) for the speed estimation and control of low-cost BDFR motor drive. The reasons behind such choice for this drive's control are: (i) MRAS-based controllers can inherently take care of the machine parameter variations which had been a challenging issue with the other available sensorless speed estimation strategies and (ii) the employment of Q as a functional candidate inevitably makes the formulation immune to the variations in stator resistance. The experimental assessment, in this respect, confirms these claims. Furthermore, the analytical validation of Popov's hyperstability criteria on the proposed controller, confirms the drive's overall stability within the investigated speed control range. The speed control performance is examined in MATLAB/Simulink. The simulation results are further validated by a real-time implementation using dSPACE-1103-based 1.6 kW BDFR machine prototype.

Discrete-Time Parameter Identification of a Surface-Mounted Permanent Magnet Synchronous Machine

A novel online discrete-time parameter identification algorithm suitable for surface-mounted permanent magnet synchronous machines (SPMs) is presented in this paper. It is developed by means of the model reference adaptive system technique and the Popov Hyperstability Criterion in order to identify SPM discrete-time model parameters. In particular, good accuracy of discrete-time parameters is required by digital control systems, particularly by predictive control algorithms, which present a low robustness against parameter mismatches. Hence, an extensive simulation study is first carried out in the Matlab Simulink environment with the aim of testing the effectiveness and robustness of the proposed identification algorithm against inverter unidealities. Then, the proposed identification procedure is experimentally validated on a predictive controlled radial-flux SPM, driven by a field programmable gate arrays control board.

Full digital deadbeat speed control for permanent magnet synchronous motor with load compensation

A full digital deadbeat controller is proposed for the speed loop to obtain better dynamic response performance in permanent magnet synchronous motor servo system. Given an expected target error function and speed command in Z-domain form, according to the deadbeat zero-pole configuration rules, the digital controller is derived to make the current command output stable in several sampling periods and the speed response also becomes stable without ripples. To reject disturbance from the load variation, an estimation method, based on model reference adaptive system through Popov's hyper stability criteria, is presented to identify online the moment of inertia and load torque. The two quantities are essential for the speed loop to achieve adaptive control by load compensation. The simulation and experimental results reveal the effectiveness of the proposed speed controller.

Model referenced adaptive control to compensate slip-stick transition during clutch engagement

Clutches are widely used in various vehicle powertrains. The engagement process of a friction clutch has three phases, i.e., open, slipping, and sticking. Transitions between different phases introduce a discontinuity to the powertrain dynamics, which has been neglected in previous research. A model referenced adaptive controller (MRAC), based on Popov hyper-stability criterion, is designed to compensate the discontinuity. MRAC adjusts the frictional torque along with the errors of the state variables compared with those of a referenced model. The designed MRAC is applied to a clutch in a bus. Simulation and experimental results under fast and slow startup cases show that MRAC can simultaneously reduce vehicle jerk and frictional dissipation when compared with the conventional controller.

Adaptive Robot Controllers: A Comparative Study

Abstract A conparative study evaluates the problem of determining the optimal control that must be exerted on the manipulator joints. Two different techniques are studied: 1) Direct adaptive control and 2) Indirect adaptive control. In the direct adaptive technique, two different approaches are used in the estimation process. The first is based on Lyapunov's stability criteria whereas the second is based on Popov's hyperstability criteria. Both approaches have the sane objective of minimizing the tracking errors of the joints in the adaptation process. In the indirect adaptive technique, the regulator parameters are updated via the estimation of the process node 1. This step, using a recursive least squares algorithm, is based on the error at the input and on the filtered dynamic model in order to avoid the acceleration measurements. Both, direct and indirect adaptive techniques, are applied to the trajectory tracking control of a 2 degree-of-freedom (d.o.f.) manipulator, and simulation results show the effectiveness of the indirect adaptive technique, especially for the estimation of the parameters.