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

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Presentation on theme: "Elevator Drives - Discussion History Requirements Motor and Control Types Industry Trends Future Drives."— Presentation transcript:

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

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

3 Otis Patent 1861

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 3-Phase Squirrel Cage Design 1889 – Otis Elevator Uses DC Motor

5 Otis DC Elevator Motor Circa 1889

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

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

8 Otis Gearless DC Machine Circa 1919

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

10 Otis Type Broadway,NYC Circa 1930s

11 History 1975-Present –Thyristor (SCR) DC Drives Control Elevators –All Analog Components in the 70s –Replaces Aging M-G Sets 1980s – Microprocessors Improve –Car Dispatch and Motor Drive Controllers

12 Otis type 84,NYC with Encoder

13 Westinghouse #205 with Encoder

14 History Late 1980s – –Variable Frequency Inverters AC Induction Motors, Geared Applications Only Early 1990s – –More AC Inverters and Motors Begin to Displace Small DC, 3-15 HP Mid-1990s – –Vector Control AC Inverters HP Almost as Good as SCR-DC. –KONE Introduces PM EcoDisc AC Machine

15 History –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 Late 1990s –

16 History –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 2000-Present –

17 Four Quadrant Operation

18 Linear power stage 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 (P V = R I 2 ) –for small nominal power up to 100 W M R controller UTUT V cc Gnd LSC U mot time U mot, I mot

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 M power stage U mot V cc Gnd pulse generator ADS, DEC, AECS, DES, MIP, PCU, EPOS time cycle time: s U mot, I mot

20 Pulsed power stage: current ripple general measures: reduce motor voltage enhance total inductance - motor choke in controller - additional motor choke enhance PWM frequency 50% 30% 70% low motor inductance additional motor choke U mot, I mot

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

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

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




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