Matrix Converter based Direct Torque Control of Induction Motor

PSG COLLEGE OF TECHNOLOGYME – Power Electronics & Drives

Dept. of EEE

Matrix Converter Based Direct Torque Control Of Induction

Motor

By:Neehar N.L.N

Guide:Mrs.P.Sweety Jose


Dept. of EEE

The direct torque control (DTC) scheme for a matrix-converter-fed induction motor drive system is a high performance motor control scheme with fast torque and flux responses. By selecting appropriate switching patterns, the advantages of DTC and benefits of matrix converters can be combined to achieve a satisfactory servo drive.

Matrix Converter based DTC

ABSTRACT

NEEHAR NLN [12MQ36] 16/07/2013 2


Dept. of EEE

Over the years, there have been many advancements in the field of induction motor control.

The main disadvantage of scalar control is poor dynamic response or sluggish response which is

due to the inherent coupling effect between Torque and flux components.

This led to development of vector control wherein the torque and flux components are decoupled so that both can be controlled independently.


INTRODUCTION

NEEHAR NLN [12MQ36] 16/07/2013 3


Dept. of EEE


Direct Torque Control(DTC):

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Dept. of EEE

Comparison property DTC FOC

Dynamic response to torque Very fast Fast

Coordinates reference frame alpha, beta (stator) d, q (rotor)

Low speed (< 5% of nominal) behaviorRequires speed sensor for continuous braking

Good with position or speed sensor

Controlled variables torque & stator fluxrotor flux, torque current iq & rotor flux current id vector components

Steady-state torque/current/flux ripple & distortion

Low (requires high quality current sensors)

Low

Parameter sensitivity, sensorless Stator resistance d, q inductances, rotor resistance

Parameter sensitivity, closed-loopd, q inductances, flux (near zero speed only)

d, q inductances, rotor resistance

Rotor position measurement Not required Required (either sensor or estimation)

Current control Not required Required

PWM modulator Not required Required

Coordinate transformations Not required Required

Switching frequency Varies widely around average frequency Constant

Switching lossesLower (requires high quality current sensors)

Low

Audible noise spread spectrum sizzling noise constant frequency whistling noise

Control tuning loops speed (PID control)speed (PID control), rotor flux control (PI), id and iq current controls (PI)

Complexity/processing requirements Lower Higher

Typical control cycle time 10-30 microseconds 100-500 microseconds

NEEHAR NLN [12MQ36] 16/07/2013 5 Matrix Converter based DTC


Dept. of EEEDesired features in frequency changers:

Simple and compact power circuit. Sinusoidal input and output currents. Operation with unity power factor for any load.


Dept. of EEEMatrix Converter: It is a forced commutated converter which uses an

array of bidirectional switches as the main power elements to create a variable output voltage system with unrestricted frequency.

It has an array of mxn bidirectional switches connecting m-phase source voltage source to a n-phase load.

Converter of 3x3 switches has the highest practical interest because it connects a three-phase voltage source with three-phase load, typically a motor.


Dept. of EEECircuit of matrix converter:


Dept. of EEEBlock diagram:


Dept. of EEELosses comparison:


Dept. of EEEBidirectional switches:


Dept. of EEECommutation circuit:


Dept. of EEEMathematical Model:


Dept. of EEEState table:


Dept. of EEEDirect method:


Dept. of EEEIndirect approach:


Dept. of EEERectifier states:


Dept. of EEEInverter states:


Dept. of EEEMaximum output-input ratio:


Dept. of EEESpace vector modulationOutput voltage vectors:


Dept. of EEESimulink Model:


Dept. of EEESimulation Results:

Output Voltage and Current waveforms


Dept. of EEE

MC based DTC:2 HP, 400 V, 50 Hz Squirrel Cage Induction Motor with following parameters:Stator Resistance and Inductance: 5 Ohms and 0.03230 HRotor Resistance and Inductance: 4.861 Ohms and 0.03230 HMutual Inductance : 0.4088 H


Dept. of EEESwitching table:


Dept. of EEESimulation Results:Load Current:


Dept. of EEESpeed waveform:


Dept. of EEEReferences: Electric Motor Drives by Vedam Subramaniam. Fundamentals of Electrical Drives by Gopal.K.Dubey. High power converters and AC Drives-BinWu,IEEE Press. Matrix Converters: A technological review-P.W.Wheeler,

J.Rodriguez,J. Clare, L.Empringham and A.Weinstein.IEEE Transactions on Industrial Electronics,Vol. 49, No. 2,April 2002.

Direct Torque Control of Matrix Converter Fed Induction Motor Drive: A Review-R.A.Gupta,Virendra Sangtani, Ajay Kumar Bansal.Proc. Of Intl. Conf. on Advances in Computer,Electronics and Electrical Engineering,2012.


Dept. of EEE Contd.

Alesina A. and Venturini M.G.B.,”Analysis and design of Optimum Amplitude nine-switch direct AC-AC Converters” ,IEEE Transactions on Power Electronics Vol. 4. NO.1.,january 1989,pp101-112.

Modeling,Analysis and simulation of matrix converters,J.Rodriguez,E.Silva,R.Burgos,F.Blaabjerk-Universidad Tecnica Federico Santa Mari,Valparaiso,Chile.

Modelling,Simulation and Analysis of Matrix Converter using Matlab and Simulink-Hulusi Karaca and Ramazan Akkaya-International Journal of Modeling and Optimization,Vol.2,No. 3,June 2012.


Dept. of EEE

Thank You