Stephen J. DODDS, University of East London Viktor A. UTKIN, Institute of Control Sciencies, Russian Academy of Sciences, Moscow Russian Academy of Sciences, Moscow Jan VITTEK, University of Transport and Communications, Zilina SENSORLESS INDUCTION MOTOR DRIVE CONTROL SYSTEM WITH PRESCRIBED CLOSED-LOOP ROTOR MAGNETIC FLUX AND SPEED DYNAMICS

BASIC PRINCIPLE nonlinear plant i.e., specified closed-loop system u y y MOTIONSEPARATION LINEARISING FUNCTION nonlinear plant uy nonlinear control law linear and de-coupled closed-loop system with prescribed dynamics

EXTENSION TO INDIRECTLY CONTROLLED VARIABLES nonlinear plant i.e., specified closed-loop system u z z LINEARISING FUNCTION nonlinear plant u z nonlinear control law available measurements controlled variables observer y

MODEL OF MOTOR AND LOAD rotor magnetic flux linkage stator currents stator voltages motor torque rotor speed stator, rotor and mutual inductances stator and rotor resistances expressed in stator-fixed frame

CONTROL LAW DESIGN 1. SIMPLIFICATION OF CONTROL PROBLEM BY INNER/OUTER CONTROL LOOP STRUCTURE inner-loop sub-plant outer-loop sub-plant master control law slave control law observers I inner loop outer loop U d  r  d  d    r I

u Two options are considered : u A High Gain Proportional Control Law with Saturation Limits u Bang-Bang Control Law Operating in the Sliding Mode u Automatic Start Algorithm bypasses Slave Control Law with simple algorithm, which applies maximum voltage to one phase until magnetic flux has grown sufficiently. Ifthen 2. Slave Control Law

3. MASTER CONTROL LAW independently controls rotor speed and magnetic flux norm with first order dynamics and time constants, T1 and T2 mastercontrol law linearising functions motor equation desired closed-loop equation

3. STATE ESTIMATION AND FILTERING 3.1. Rotor Flux Estimator based on motor equations flux component estimates are limited on the basis that they have zero long-term averages with eliminate flux estimate then given by:- ROTOR FLUX ESTIMATION ALGORITHM by numerical integration

slope K I 3.2. Pseudo-Sliding Mode Observer and Angular Velocity Extractor motor equationUI I * (not used directly) -v For classical sliding -mode observer:- For pseudo sliding -mode observer:-,, angular velocity extractor

3.3 Filtering Observers Rotor angular velocity and load torque observer Rotor magnetic flux observer

OVERALL CONTROL SYSTEM BLOCK DIAGRAM

Simulation Results for High-Gain Slave Control Law

Simulation Results for Sliding Mode Slave Control Law

Comparison of Simulated System Behaviour with Ideal Transfer Function for High Gain Proportional CL

Comparison of Simulated System Behaviour with Ideal Transfer Function for Bang-Bang Slave CL

Experiments with Induction Motor Experimental Bench of East London University, UK January Voltages Ualpha v. Ubeta [V] Currents Ialpha v. Ibeta [A] Flux Links PSIalpha v. PSIbeta [Vs] Ang. Velocities & Torque v. time [rad/s], [Nm] time [s]

Experiments with Induction Motor,  d = 200 rad/s, T 1 = 0.5 s a1) speed up b) Estimated variables from observers c) Real and ideal rotor speed a) stator currents and rotor flux a2) steady state b1) estim. rotor flux norm and load torque b2) estim. rotor speed and load torque c1) estim. rotor speed, SM observer c2) real and ideal rotor speed

Conclusions and Recommendations u Forced Dynamic Control introduces a new approach to the control of el. drives with induction motors, when behaviour of the rotor magnetic flux and rotor speed dynamics are precisely defined. u The experimental results show good agreement with the theoretical predictions. u Further improvement of the Forced Dynamics Control can be done with MRAC or SMC based outer control loop.