LV Drives â€“ Basics & beyond
Presented by Rockwell Automation
What is VFD ? What is a VFD
• Diode rectifier converts AC line voltage to fixed voltage DC. • DC voltage is filtered to reduce current ripple from rectification. • Inverter changes fixed voltage DC to adjustable PWM AC voltage.
How Drives Can Can Help How Drives Help Save substantial energy costs (due to direct speed control) Improves Process by smooth speed control Save Energy costs by reducing maximum utility demand charges Reduce Motor stress & Increase Life of mechanical equipment due to ‘soft starting’ (lower heat, vibration, and transient torques)
Lower chances of System disruptions (by lowering current inrush from 600% to 100-150%)
Complete Motor Protection in build Automatic Energy Saving Feature Substantially brings down – Down time & Maintenance costs
Basic Control Classes for AC drives
Basic Volts/Hertz Volts/Hertz Volts/Hertz Control Control (V/Hz) (V/Hz)
Sensorless SensorlessVector Vector Control with Control with slip slipcomp. comp.
Flux FluxVector Vectoror or Field Oriented Field Oriented Control Control w/ out w/ outEncoder Encoder
Flux FluxVector Vectoror or Field Oriented Field Oriented Control Control w/ Encoder w/ EncoderFdbk Fdbk
Vector Control vs Flux Vector
Vector Control â€“ Acknowledges that motor current is the vector sum of the torque and flux currents and uses this information to provide better control of motor speed/torque.
Flux Vector Control â€“ The ability to independently control the flux and torque in a motor for the purpose of accurate torque and power control.
standard Duty classes IEC-146( converter) Duty Class
Rated current values for converters& test conditions for assemblies
100% continuous,150% for 1min in 10 mins
100% continuous,150% for 1min in 5 mins
100% continuous.125% for 2 hours, 200% for 10 sec
100% continuous.125% for 2 hours, 200% for 60 sec
100% continuous, 150% for 2 hours,300 % for 60 sec
A,B,C of Sizing & selection
Sizing & selection Application ( Types of load ):CT,VT, CHP Braking: DC, Resistance, Regeneration Communication: Devicenet, control net , Modbus, Ether Net Cable Length: Choke, Terminator, Sin Filter Feedback: Tacho, Encoder Power: As per Duty class Temperature: 45 or 50 degree centigrade
ENERGY CONSERVATION USING VARIABLE SPEED DRIVES
WHERE CAN ENERGY BE SAVED USING DRIVES ? Fans, pumps, blowers etc where the load vary depending upon the flow rate demanded by process. Applications where mechanical methods / eddy current drives are being used to limit the rated flow. The most popular applications which result in energy savings are fans and pumps.
“ENERGY” Saving by Variable Speed Drives
Application Fan and Pump Fans, pumps, blowers load vary depending upon the flow rate demand. •Requirement of application. •Characteristics of Fan and Pump. •Principle diagram of Adjusting the flow rate. •Advantage of Using Drives
THE PARAMETERS INVOLVED :
PROCESS-Flow Rate, Load Cycle. FAN SIDE -Torque, Speed & Power. DRIVES SIDE -Torque, Speed, Current, Power & Motor Details. FANS & PUMPS -THE CHRACTERISTICS TORQUE α(Speed)2 POWER CONSUMED α (Speed)3 If speed decreases, the power consumption decreases in a cubic manner.
Drive Advantages High motor power factor even at partial load Smooth start / stop reduces shock loading on pipelines, reduced torque on motor and peak KVA demand is reduced . Efficient fluid flow , better energy management during non-peak demand Accurate flow control as per process needs improves product quality (metering, mixing applications) Optimum sizing of pumps , low running cost. Multiple motor starts and stops are permitted. Pipeline leakages are better controlled. Throttling Valve, additional piping and friction avoided Remote and easy control of Drive and integration with higher level automation is possible.
Variable Torque Variable Inlet Vane To reduce the flow from 100% to 60% , input power requirements are reduced from
to 62 %
ID Fan application
Variable Torque Outlet Damper
ID Fan application
To reduce the flow from 100% to 60% , input power requirements are reduced only from
100 % to
Variable Speed Drive Reduction of flow from 100% to 60% , results into Input power requirements reduction from
100% to 22% Saves 78% of Energy
ID Fan application Energy Saved
Power α (Speed) Torque is Constant
Some Applications Food processing equipment
Conveyor equipment Packaging machinery
Press and stamping Coal Feeders Conveyor Crane/Hoists
Wood working machinery
Press and stamping Winder
20 % REDUCTION IN SPEED REDUCES 20 % ENERGY CONSUMPTION
Constant Power Zone Example: Blower Spindle
Mixer etc.. NO Energy Saving
Minerals, Mining and Cement,
Mine cooling fan - AC drive instead of damper Mine submersible pump - AC drive instead of throttling Clay workshop ID fan - AC drive instead of damper Mine ore conveyor - AC cage motor + drive instead of slip-ring motor Cement factory ID fan - AC drive instead of damper
Power plant ID fan - AC drive instead of fluid coupling Power plant FD fan - AC drive instead of inlet guide vanes Power plant fans - AC drive instead of inlet guide vanes Power plant booster fan - AC drive instead of inlet guide vanes Boiler extract fans - AC drive instead of dampers Boiler feed pump - AC drive instead of fluid coupling District heating pump - AC drive instead of throttling
Metal and Manufacturing Metal industry ID fans - AC drive instead of damper Metal industry scrubber pump - AC drive instead of throttling Steel melting plant fan - AC drive instead of damper Steel mill roller table - AC drive instead of fixed speed Wastewater pumping - AC drive instead of on-off control Water booster pump - AC drive instead of throttling Water treatment pump - AC drive instead of on-off
AC Drive and Motor Installation Practices Line Transients
Rockwell Automation Common Mode & Capacitive Coupling Tell me again why Iâ€™m using drives?
Grounding & Bonding
A little protection and good technique go a long way to insure a good drive installation
Selection of Motor Standard Motor( Insulation level ???) or Inverter Grade Motor Forced cooled or self cooled Operating Area: safe or hazardous Bearing Insulation
Motor Insulation & Choke insulation
Design Review Checklist – Line Side • Distribution System – Grounding – Cable type
• Transients and Harmonics – Converter type – Line impedance
• Common Mode Noise – EMI noise – Cable type – Cable configuration
Design Review Checklist – Load Side • Reflected wave – Motor insulation – Cable type
• dV/dt – Motor insulation – Motor CIV – Cable charging
• Common Mode Noise – – – –
EMI noise Bearing currents Cable type Cable configuration
Reflected Wave Result
Protect the Motor • Output Reactor with and without resistor between drive & motor – – – – –
Slopes off the waveform (lengthens rise time) Reduces destructive force for same amplitude Allows longer lead lengths With resistor even longer lead lengths Reactor does create voltage drop
• Output Filters – dV/dt limiters • 1204-RWR2, 1204-RWC-17A • 1204-TFA1, TFB2 “terminator” – Sine Wave • Filters
Line Current Harmonics
Root Cause of Problems with Other Equipment
Current Harmonics create
What problems do HARMONICS cause?
• • • • • • • • •
Increased Utility current requirement inability to expand or utilize equipment Component overheating distribution transformers & wires Nuisance tripping causing lost productivity sensitive equipment Equipment malfunction due to multiple or loss of zero crossing Noise transfer to other loads possibly even other utility customers Incorrect meter readings, relays malfunction maintenance time Communication or Telephone Interference problems Excitation of Power System Resonance's creating over-voltage’s Voltage Flat Topping Problem
How can we reduce the harmonic current? • • • • • • • •
DC link choke within the drive line reactor passive filter active filter phase shifting loads harmonic mitigating transformers multi-pulse converters active front-end
Guidelines to be taken care during installation of Drive system
• • • • • • • • • •
Drives to be installed in clean dry and corrosion free environment Keep panel door closed. Use suction type vacuum cleaner to clean dust. (No blower) Room A.C should have humidity control. Use antistatic protection while handling electronic parts. (Self grounding). Cable from drive to motor should be 3 core. (Not 3.5 core) Never run control or drive input wires in the same conduit as the drive output wires. Keep the distance from the drive to the motor as short as possible to maximize motor life. Never connect incoming supply to drive output terminal. Do not conduct insulation test on motor terminal with cables connected to drive output.
Guidelines to be taken care during installation of Drive system
• • • • • • •
Dedicated earth connection from drive P.E terminal to motor P.E terminal is recommended. (No welding using this earth permitted) Earth conductor of drive panel, motor, transformer should have at least 50 % cross section of input phase conductor. Earth strip of panel should not be used for any other purpose including welding which may lead to electronic component failure. All 24V/ 10 V (4-20 mA) control signal cables should be twisted pair screen cables, screen to be grounded at receiving end. Do not store the drive more than twelve month without charging. Set Lower Drive carrier frequency Add suppression to all inductive loads (electric brakes, relay coils, solenoids)
PowerFlex Family of Drives • Power ratings from 0.2kW (0.25 Hp) single phase to 25MW (34,000 Hp) at medium voltage • Seamless control system integration – maximize uptime • Decrease development time by as much as 70% with Premier Integration —RSLogix 5000 Software with PowerFlex drives add-onprofiles • Increase productivity and flexibility with integrated safe speed control technology and safe torque off options • Flexible control – simplifies operation, reduces training & costs – Common operator interface & integration capabilities – Consistent programming structure – Consistent software tools – Variety of packaging designs
0.2 kW (0.25 Hp) to 25.4 MW (34,000 Hp)
PowerFlex Family of Low Voltage Drives PowerFlex drives meet worldwide standards out of-the-box, achieving EMC, global voltage and safety requirements. All PowerFlex drives offer commonality in networks, operator interface and programming — factors that significantly contribute to ease-of-use and faster application start-up. • PowerFlex Component Class AC drives offer you cost-effective motor control for machine-level and stand-alone applications (PowerFlex 4, 4M, 40, 40P and 400) • PowerFlex Architecture Class AC drives are designed for advanced application flexibility and control system integration (PowerFlex 70, 700, 700L, 700H, 755, 700S) • PowerFlex DC drives are designed for coordinated drive control and drive system applications (PowerFlex DC)
DSI Communication Products
Profibus DP USB Converter
Ext. DSI Kit
PowerFlex 750-Series AC Drives • The PowerFlex 750-Series of AC drives offers more standard features and selection for control, safety and supporting hardware options than any other drive in its class – – – – – –
Standard embedded Ethernet Standard embedded I/O Predictive diagnostics Real Time Clock Safety - Safe Speed and Safe Stop(EN-954) DeviceLogix - Instruction Types include: -- Boolean
-- Select / Limit
-- Timer / Counter
– Features: – Positioning Functions – Feedback Options – I/O Slot Options
-- I/O Slot Options -- RoHS Compliant
PowerFlex755 Drive Awarded Control Engineering 2010 Engineersâ€™ Choice Award for drives, motion control and motors category
Performance Improvement - Load Sharing In the world of DRIVES Load Sharing: Involves multiple drives/motors powering the same process • Each drive contribute a fair share of torque to do work proportional to its own capacity • When uncoupled roller must not run away - use min torque/speed comparator feature. • Perfect Speed Synchronization and accurate Torque control
Compressors - Concept - Conventional Control
P r e 7.0 s s u r 6.5 e Ksc 6.0
Lower Limit - Reqd. Pr.
VFD Advantages In Compressors No loading / Unloading Cycles Less Leakages Constant Lower Pressure Process
Better Motor Efficiency Higher
Controlled Accel / decel Time Lower Lower
Starting Torque Starting Current
Perfect Hoist Load Control Benefits include: –
Assured control of the load. • TorqProveTM assures that the mechanical brake has control of the load when stopping the drive, and the drive has control of the load when releasing the brake during a move command • TorqProveTM and Force TechnologyTM helps eliminate concerns with brake timing and environment changes inherent in V/Hz drives Reduced set-up time • Very easy to set-up – only a few parameters • No PLC programming required for function (brake control is performed by drive)
References : Bhutan Ferro Alloys Ltd on Hot Metal Bucket BALCO Korba for Bucket Pick and drop Bhushan Steel Orissa LMW Foundary Shop Hindustan Zinc etc….
Lifting be Liftingapplications applicationscan cannow now besolved solved TM easily featurein inthe the easilyusing usingthe theTorqProve TorqProveTMfeature PowerFlex PowerFlex700. 700.
Can CanHold HoldFull FullLoad Loadin inair airWithout Without Mechanical MechanicalBrakes Brakes?............. ?.............
Auto Energy Saving Feature Auto-Economizer - Extra Saving
“Idle Mode” Energy Saver Reduced Load Automatically fold back Voltage to reduce motor flux
A key in Press like Applications
Confidential -- For Internal Use Only. Copyright © 2008 Rockwell Automation, Inc. All rights reserved.
Performance Improvement - Premier Integration with Powerflex Drives
Controller-based Automatic Device Configuration (ADC) Controller will automatically detect a node replacement, flash it if necessary, and download the configuration settings
Incident at 2:00 AM!!
Benefits Using RA Drive with RA Controllers – Pre.Intg. • Reduce drive system development time by as much as 70%*: – Use one software tool to configure the entire Logix / drive system – Controller and drive network connections are configured at the same time • eliminates I/O mismatch errors – Auto-generation of descriptive tag names – Auto-generation of respective tag data types – All drive configurations are saved in the RSLogix project file and in the Logix controller
Readymade PowerFlex Global Objects Key Differences Programming the 1st Drive Competitor’s Drive
Key Differences Programming Ten Additional Drives PowerFlex Drive ~7 minutes Competitor’s Drive ~42 minutes
What makes RA Drives More Reliable
Ambient Temperature of 50 Degree C. Flexible performance with ForceTM Like Technology. Seamless Integration Built in DC Chokes to abate input Current Harmonics (Obeys IEEE 519 -1992 Standards) with 97.5% Efficiency Power Devices having PIV of 1700V and Transient Protection of 6KV Built in Software to control the effect of reflected wave Built in EMC Filters and common mode core to address noise related issues. Conformity to EMC directives and european Standards. Excellent Feature of Zero Stacking PTC input to the Drive Internal family of communications and HIM modules 7th IGBT â€“ Chopper is internally Provided Over Load Capacity as per Application. Complete Output Short Circuit Protection Compact Size
Thanks For your Patient Listening Lakhbir Singh Area Manager( East) â€“ Drives Rockwell Automation +91-9874624151
LV Drive basics & beyond