Željko Despotović, Aleksandar Ribić, Mihajlo Pupin Institute, Belgrade, Serbia 15 th INTERNATIONAL SYMPOSIUM on POWER ELECTRONICS - Ee 2009 NOVI SAD, REPUBLIC of SERBIA, October th, 2009 LOW FREQUENCY IGBT CONVERTER FOR CONTROL EXCITING FORCE OF ELECTROMAGNETIC VIBRATORY CONVEYORS

VIBRATORY CONVEYING Vibratory cconveying process is based on a sequential throw movement of particles The vibratory conveyors are widely used device in various technological processes for transporting and finishing materials Vibrations of tank, i.e. of a “load- carrying element” (LCE), in which the material is placed, induces the movement of material particles, so that they resemble to a highly viscous liquid and the material becomes easier for conveying

VIBRATORY CONVEYING ALONG THE HORIZONTAL SURFACE

VIBRATORY CONVEYING ALONG THE SLOPED DOWN SURFACE VIBRATORY CONVEYING ALONG THE SPIRAL ELEVATOR

VIBRATORY DOSING;CHARGING and (or) DISCHARGING

VIBRATORY DRIVE MECHANICAL -with eccentre -centrifugally -inertional ELECTRICAL -rotational→ electr. motion -linear→electromagnetic drive

VIBRATORY DRIVE WITH ECCENTRE

CENTRIFUGALLY VIBRATORY CONVEYING DRIVE (a)- eccentric drive with one mass, (b)- eccentric drive with two masses

Electromagnetic Vibratory Conveyor with Fixing Inductor

Electromagnetic Vibratory Conveyor with Fixing Inductor and Directional Exciting Force 1-LCE 2-flexible elements 3-base 4-rubber pads 5-magnetic core 6-winding coil 7-armature 8-vibratory trough 9-inductive sensor 10 - storage hopper 11-movable shutter

Analytical Model of Electromagnetic Vibratory Conveyor i=1, 2,.., n ss ; n ss = 4 Lagragian of system Lagrange equation of motion

THE SIMPLIFICATION of ANALYTICAL MODEL m b >> m k Frequency Characteristics of Vibratory Conveying System (Vibratory Conveyor) REALITY

EVA like as a Generator of Force (a)-mechanical model, (b)-magnetic circuit, (c)-equivalent electrical circuit Electro Magnetic Force (EMF) mechanical equation electrical equation static characteristic

Traditional Solution Controlling of Vibratory Conveying (a)-potentiometer (b)-auto transformer (c)-variable inductivity (d)-magnetic amplifier These ways of control are coarse and related to large energy losses, consequently this significant affect to rise of cost and increase dimension of regulation equipment

The important overcome disadvantage of traditional ways of control is effectuated of development semiconductor power converters Application of electromagnetic vibratory drive in combination with the power converters provides flexibility during work Consequently, it is possible adjustment amplitude and (or) frequency of EVA coil current, i.e. adjustment intensity and frequency of exciting force applied on conveying device, i.e. ADJUSTMENT AMPLITUDE and (or) FREQUENCU of MECHANICAL OSCILLATIONS

Power Converters with Phase Angle Control (PAC) SCR power converters; (a)-unidirectional, (b)- bidirectional AMPLITUDEFREQUENCY

Switching Power Converters in Vibratory Conveying Controlling of EVA current it is possible adjustment electromagnetic exciting force applied on vibratory trough of conveyor From electrical standpoint, the EVA is mostly inductive load by its nature, so that adjusting the current of EVA is possible by: -PWM voltage or current-mode control -ZVS or ZCS resonant control Triangle and sinusoidal half-wave of EVA current In this way it is provided amplitude and (or) frequency control of vibratory conveying

Control of Sine Half-Wave of EVA Current

The waveform of electromagnetic driving force ( a)-graphical harmonics representation, (b)-analytical representation The Fourier spectrums at triangle drive current (a)- driving (exciting) force (b)-displacement

Control of Triangle Half-Wave of EVA Current

The waveform of electromagnetic driving force (a)-graphical harmonics representation, (b)-analytical representation The Fourier spectrums at triangle drive current (a)- driving (exciting) force (b)-displacement

Current-Mode Control in Vibratory Conveying- generating triangle wave shape of EVA current Control circuit to provide adjusting triangle wave shape of EVA current; (a)-principal scheme, (b)-characteristic waveforms

The influence reference value of peak current on the output displacement of LCE (a)-wave shape of output displacement and EVA current, (b)-detailed presentation of interval I, (c)-detailed presentation of interval II

The Control Scheme of Resonant Electromagnetic Vibratory Conveyor

The Slides of Implemented Prototype

IMPLEMENTED PROTOTYPE of VCD

Mounting of acceleration sensorMounting of displacement sensor Electromagnetic Vibratory Actuator-EVA Vibratory trough-top view

IMPLEMENTED PROTOTYPE of POWER CONVERTER

Power Converter PLL circuit Acceleration Transmitter

EXPERIMENTAL RESULTS

AMPLITUDE CONTROL - sinusoidal drive EVA - triangle drive EVA (a)- VW=6mm (b)-VW=0.5mm (a)- VW=6mm (b)-VW=0.5mm

Oscilloscopic Records of Characteristic Waveforms for VCD with Transistor Control Voltage and current of EVA (a)- triangle drive (b)-sinusoidal drive

THE VIBRATORY DRIVE MOVIES AMPLITUDE CONTROL FREQUENCY CONTROL

CURRENT 1A/cDISPLACEMENT 0,5mm/cTime 5 ms/c AMPLITUDE CONTROL

FREQUENCY CONTROL Time 5 ms/cCURRENT 1A/cDISPLACEMENT 0,5mm/c

AMPLITUDE –FREQUENCY CONTROL

PARTICLE TRAJECTORY

CONCLUSIONS The most significant contribution of this research is development optimal control of electromagnetic resonant vibratory conveyors and increase of theirs energy efficiencyThe most significant contribution of this research is development optimal control of electromagnetic resonant vibratory conveyors and increase of theirs energy efficiency This is reached compensation of overall influences which relate to the violation of required resonant regime and changing resonant frequencyThis is reached compensation of overall influences which relate to the violation of required resonant regime and changing resonant frequency The most dominated influences are:The most dominated influences are: -changing of conveying material mass -changing stiffness of flexible element -variation of mains voltage supply

☺freedom to operate a VCD with any natural (resonant) frequency from 5 Hz to 150 Hz →frequency control ☺the controller will continually search for the natural frequency of the vibratory conveyor (resonance) and excite it at that frequency (active tuning); in the located natural (resonant) frequency, it is possible to tune amplitude and time duration of the EVA coil current i.e. amplitude oscillations of the LCE →amplitude control ☺flexible automation with minimum change-over time because electronics replace the comprehensive and the complicated calibrations and mechanical settings ☺many conveyors can be placed on the same electrical circuit without fear of circuit overload ☺VCD can operate nondependent on mains frequency (50Hz-Europe or 60Hz-North America) without changing the conveyor springs or balancing masses ☺energy efficiency: minimum EVA coil current minimum EVA coil heating minimum supply current minimum power consumption HIGH PERFORMANCE OF VIBRATORY DRIVE

The idea for development proposed transistor switching converter is proceed from lasting experience obtained on development and realisation SCR converters for drive vibratory conveyors in cement industry

At the END THANK YOU IN ATTENTION!!!!