1. Elevator Drives - Discussion
History
Requirements
Motor and Control Types
Industry Trends
Future Drives 1

2. 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 2

3. Otis Patent 1861 3

4. History 1873 – First Modern DC Motor
1874 – J. W. Meaker Door Opener Patent
1880 – First Electric Motor Controlled Elevator Siemens / Sprague
– Tesla AC Induction Motor Phase Squirrel Cage Design
1889 – Otis Elevator Uses DC Motor 4

5. Otis DC Elevator Motor Circa 18895

6. History 1891 – Ward Leonard Variable Speed Control
AC Induction Motor Turning DC Dynamo
Rheostat to Control Generated Voltage
DC Voltage Controls DC Motor Speed
’s – Ward-Leonard M-G Sets and DC Motors Used for Variable Speed Elevators
AC Motors Used 1 and 2 Speed Starters 6

7. Otis No. 1 Geared DC Machine with DC Motor
Circa 1915 7

8. Otis Gearless DC Machine
Circa 1919 8

9. M-G Set Controls (Otis Elevator, 1920’s)

10. Otis Type 84 26 Broadway,NYC Circa 1930’s10

11. History 1975-Present 1980’s – Microprocessors Improve
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 11

12. Otis type 84,NYC with Encoder12

13. Westinghouse #205 with Encoder13

14. History Late 1980’s – Early 1990’s – Mid-1990’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 HP Almost as Good as SCR-DC.
KONE Introduces PM EcoDisc AC Machine 14

15. 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 15

16. 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 16

17. Four Quadrant Operation17

18. Linear power stage R M Umot, Imot LSC Vcc time advantages
simple, low priced controller
low electromagnetic noise level
no minimum inductance needed
disadvantages
high power losses at the final stage at high currents or low motor voltages (PV = R I2)
for small nominal power up to 100 W
controller R UT M
Umot
Gnd

19. Pulsed power stage (PWM)
advantages
low power losses
high efficiency
for higher nominal power
disadvantages
electromagnetic noise in the radio frequency range
high power losses in the motor at standstill
minimum inductance necessary
Vcc
power
stage
pulse generator M
Umot
Gnd
ADS,
DEC, AECS, DES,
MIP, PCU, EPOS
Umot, Imot
time
cycle time: ms

20. Pulsed power stage: current ripple
general measures:
reduce motor voltage
enhance total inductance
motor choke in controller
additional motor choke
enhance PWM frequency
low motor inductance
50% 50%
additional motor choke
Umot, Imot
30% 70%

21. Time scales in control loops
frequency kHz
mechanical time constants
"slow" position controller
position controller MIP
speed controller
current controller
speed controller as "link" between fast current controller and a slow position control (PLC)
PWM cycle time ms
cycle time

22. Figure : PWM Control Signal
PWM(Pulse Width Modulation
Cambiando il duty cycle, la velocità cambierà
Lo scopo è :
1. Ridurre la dissipazione di potenza.
2. Ridurre I problemi di raffreddamento dei transistors)
Figure : PWM Control Signal

23. Duty cycle
si definisce duty cycle d il rapporto tra la durata del segnale "alto" ed il periodo totaleT del segnale, e serve ad esprimere per quanta porzione di periodo il segnale è a livello alto:

24. PWM Un segnale PWM (Pulse Width Modulation ovvero modulazione a variazione della larghezza d'impulso) è un' onda quadra di duty cycle variabile che permette di controllare l'assorbimento (la potenza assorbita) di un carico elettrico(nel nostro caso il motore DC), variando modulando) il duty cycle.

25. Un segnale PWM è caratterizzato dalla frequenza (fissa) e dal duty cycle (variabile);
si deduce dalla Figura, il duty cycle è il rapporto tra il tempo in cui l'onda assume valore alto e il periodo T (l'inverso della frequenza: T=1/f)
Es. un duty cycle dell'80% corrisponde ad un'onda quadra che assume valore alto per l'80% del tempo e basso per il restante 20%,

26. DC Motor Drives
DC motor speed control using Switching Control or PWM

27. Power Electronic converter
H-bridge converters circuit