Elevator Drives Past, Present and Future - PowerPoint

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					  Elevator Drives
Past, Present and Future
        As Presented
              at
     NAVTP Annual Forum
       Atlanta, Georgia
         May 3, 2007
Elevator Drives - Discussion
  History
  Requirements
  Motor and Control Types
  Industry Trends
  Future Drives
             History
 236 BC – First Passenger Lift,
           Archimedes
 1853 – Safe Elevator Demo,
         Elisha Otis
 1857 – First Safe Elevator
         Installation,
         Cooper Union, NYC
 1861 – Otis Elevator Patent
Otis Patent 1861
                 History
 1873 – First Modern DC Motor
 1874 – J. W. Meaker Door Opener Patent
 1880 – First Electric Motor Controlled
        Elevator Siemens / Sprague
 1882-1889 – Tesla AC Induction Motor
              3-Phase Squirrel Cage Design
 1889 – Otis Elevator Uses DC Motor
     Otis
      DC
 Elevator
   Motor

Circa 1889
                    History
 1891 – Ward Leonard Variable
          Speed Control
  – AC Induction Motor Turning DC Dynamo
  – Rheostat to Control Generated Voltage
  – DC Voltage Controls DC Motor Speed
 1900-1970’s – Ward-Leonard M-G Sets
                    and DC Motors Used for
                    Variable Speed Elevators
 AC Motors Used 1 and 2 Speed Starters
Otis No. 1 Geared DC Machine
         with DC Motor
                Circa 1915
Otis Gearless DC Machine

           Circa 1919
 M-G Set Controls
(Otis Elevator, 1920’s)
Otis Type 84
 26 Broadway,NYC

 Circa 1930’s
                 History
 1975-Present
  – Thyristor (SCR) DC Drives
    Control Elevators
  – All Analog Components in the 70’s
  – Replaces Aging M-G Sets
 1980’s – Microprocessors Improve
  – Car Dispatch and Motor Drive Controllers
Otis type 84,NYC
      with Encoder
Westinghouse #205
  with Encoder
                   History
 Late 1980’s –
  – Variable Frequency Inverters AC Induction
    Motors, Geared Applications Only
 Early 1990’s –
  – More AC Inverters and Motors Begin to Displace
    Small DC, 3-15 HP
 Mid-1990’s –
  – Vector Control AC Inverters 10-40 HP Almost as
    Good as SCR-DC.
  – KONE Introduces PM EcoDisc AC Machine
                   History
 Late 1990’s –
   –   Custom Gearless AC Induction Machines
   –   First Fully Regenerative AC
       Elevator Drives
   –   Much Discussion on PM-AC and MRL
   –   SCR-DC Still Used for Medium and
       Large Building Mods
                       History
2000-Present –
  –   More PM-AC Motor Manufacturers. PM Gearless
      Begins to Replace AC Geared
  –   EU Focus on Efficiency and Harmonics/EMC
  –   Lower Cost IGBT Inverter Components
  –   North America Begins to Focus on Energy Reduction
  –   New Construction Leaning toward AC
  –   SCR-DC Still Used on Medium-Large Building Mods
Elevator Drive
Requirements
                       Elevator Duty Cycle




    2.5
P
O
W
                                         EMPTY CAR
E           FULL CAR
R   1.0

K
I     0
L
O
W   -1.0   EMPTY CAR                      FULL CAR
A
T
T
S
    -2.5
Four Quadrant Operation
     What Customers Want
 Repeatable Elevator Performance
 Smooth Operation
 Reliable Operating Life
 Effortless Installation
 Custom Control Interface
 High Efficiency
 Conformance to All Codes
 Low Installed Cost
Elevators vs. Industrial Applications
   Infinitely Variable Speed Range
   Infinitely Variable Torque Range with
    Smooth Bump Less Operation
   Millions of Repeated Operating Cycles
    with High Peak Torque
   High Inertia Resonant Load
   Accurate Stopping Position
   Unattended Operation 24/7/365
Elevators vs. Industrial Applications

      Quiet Operation
      Long Operating Life
      Long-Term Product Support
            Types of Motors
 DC Shunt Field
  – High Speed Geared
  – Low Speed Gearless
  – Full HP Range 5 – 600 HP
  – 89–94% Efficient
  – High Torque Capacity Accel/Decel
  – In Elevator Service for 70+ Years
  – Requires DC Generator, SCR or Other AC-DC
    Power Conversion from AC Utility Power
  – DC Motor Can Act Like a Generator
          Types of Motors
 AC Induction
  – High Speed Geared, 2–75 HP
  – Few Low Speed Designs for Gearless
  – 85–94% Efficient
  – Many with Single or 2 Speed Starters
  – Can be Variable Speed by Inverter Control
    of Frequency
  – Torque Strength Derived from Out of Phase
    Excitation Current
  – Requires Flux Vector Control for Wide
    Operating Speed Range
  – Can Act Like a Generator
             Types of Motors
 AC Permanent Magnet (PM)
  – New Designs for Compact Gearless Machines
  – Torque Strength from Permanent Magnets
  – 90–95% Efficient
  – Compatible with Inverters to Control Speed
  – Requires Synchronous Flux Vector / Angle Control
    to Regulate / Modulate Torque
  – Supply Limited to Specialty Machine Builders
  – Not Suitable for High rpm Speed Geared Designs
  – Can Act Like a Generator
           Modernization
 Why keep a DC machine?
  – Many large DC machines cannot be
    easily replaced with AC.
  – Large Installed Base of DC Machines
    Worldwide
  – DC Motors and Machines are in Good
    Working Order and Provide Excellent
    Ride Quality
           Large DC Machines
 Otis 72
and 269
       Types of Motor Drives
For DC Motors     For AC Motors
 M-G Set          Variable Voltage
 SCR-DC           V V V F Inv. (V/Hz)
                    Open/Closed Loop
 PWM-DC
                   Vector Control Inv.
                    Open/Closed Loop
                   Synchronous PM Inv.
                    Closed Loop
                   Regen or Non-Regen
  Elevator Power Consumption
        …the need for Regeneration
 Horsepower = Torque x Speed
 Gearless Friction Losses are 10-20% of Elevator
  HP Rating
 Moving inertia absorbs energy during acceleration
  that must be removed during deceleration.
 Mechanical, electric and electronic losses are
  proportional to torque or current flow.
 Energy Wasted / Dissipated During Deceleration
  = Heat
 Excessive heat in control rooms must be removed.
 Practical Energy Considerations
 Low Speed Elevators 50–150 fpm
  – Almost Always Geared… or PM Gearless
  – Low Speed Usually Means Low Power
    2-35 HP / 2-25 kW
  – Most power is consumed by frictional losses.
  – True regeneration is not critical.
  – High Gearbox Losses During Regeneration
  – Drive type makes little difference in overall
    energy consumption.
  – If DC, Good Candidate for Conversion to AC by
    Replacing Motor
  – Low Installed Cost is Usual Critical Issue
    Practical Energy Considerations
 Medium Speed Elevators 150–450 fpm
  – Geared and Some Gearless… Including PM
  – 15-60 HP / 12-45 kW
  – Lower Frictional Losses in Gearbox
  – Recovery of inertia energy becomes important,
    particularly with gearless.
  – Resistive Braking Still Possible but Need to Perform
    Heat Load Calculations for Equipment Room
Practical Energy Considerations

 High Speed Elevators 500-1,600+ fpm
     – Low Friction Gearless
     – 45-600 HP / 34-450 kW or Larger
     – True Regeneration is Mandatory
      Industry Trends
 Energy Consumption Reduction
  – kW-hrs / Month
  – Harmonics, Power Factor
 Performance
  – Reduced Floor–Floor Time
  – Reduced Vibration
 Low Maintenance
  – Cleanliness
 Larger PM Machines
  – More Gearless Applications
  Energy Consumption
 Elevator Speed and Payload
 Frequency of Use
 Hoist Way Efficiency
 Motor Efficiency
 Power Conversion Efficiency
 Idle Losses
 Regeneration
      Drive Type Comparison
Desired             Diode –      PWM -
Feature      SCR-DC PWM Inv      PWM
Installed
  Cost                    
Smallest     External
vol. Wt.      XFMR        
Pwr conv      90%
efficiency   w/ XFMR    93-96%   92-94%
       Drive Type Comparison
 Desired              Diode –   PWM -
 Feature     SCR-DC   PWM Inv   PWM
 Regen-
 eration               No       
   Low
Harmonics      No       No       

  Unity
Pwr Factor     No       No       
      Drive Type Comparison
Desired             Diode –     PWM -
Feature    SCR-DC   PWM Inv     PWM
Flexible    With     Below
Motor V    XFMR     Vac input    
Stand-by
Friendly     No                 
AC / DC
 Motor       No        No        
          Future Expectations
 More PM Gearless
  – Low and High Power
 More Interest in Energy Conservation
  – Overall Efficiency
  – Regeneration
 More Restrictions on Harmonics and EMC
  – Sinusoidal High pf Utility Line Current
  – All Inclusive Drive Units with Filters
       Future Elevator Drives
 PWM-PWM Double Converter-Inverter
  – Regulated Harmonics
  – Unity pf
  – Fully Regenerative
  – Compatible with DC Stand-by Power
 PM Operation without Resolver
  – Electronic Alignment Sensing
 Compact All Inclusive Packaging
 Works with AC Ind. or PM or DC Motors
     World’s Tallest Buildings




Magnetek has Elevator Drives in 17 of
 the 30 tallest buildings in the world.