ENERGY SAVING ISSUES IN RAILWAY AUTOMATION

Transcription

1 ENERGY SAVING ISSUES IN RAILWAY AUTOMATION P. Colaneri DEIB, Politecnico di Milano - Italy 1 December 12, Collaboration with Alstom Transport

2 Introduction Figure 1: Comparizon SNCF 2012: Raiway transportation is the most energy-efficient mode of transport, and electrification is the most energy-efficient way to power the trains. 68% w.r. cars, 73% w.r. airplanes.

3 Summary Optimization for a single train Optimization at system level Control strategies for power losses reduction in high speed trains Ecodrive: speed tuning for energy saving in railway vehicles Conclusions Collaborative ecodrive Collaborative antiskid

4 Control strategies for power losses reduction Figure 2: New pendolino Reduction of the harmonic losses in motors and transformers through modulation of the DC-link voltage. The method has been implemented in ALSTOM Control for the New Pendolino Cisalpino for SBB (15kVac, 16.7Hz).

5 Control strategies for power losses reduction Figure 3: Power scheme Monophase transformer 15kV/1770 V, four secondary drives, rectifiers AC/DC (called PMCF), DC link, resonant filter, capacitors, inverters, motors.

6 Control strategies for power losses reduction Figure 4: General traction drive Conduction losses (IGBT), commutation losses (IGBT), thermic losses, Joule losses, harmonic losses, Foucalt losses, iron losses. V dc = g 2 (ω m,t dem,v cat ), P = g 1 (x,u), ẋ = f (x,u) V min V dc V max

7 Control strategies for power losses reduction Recap: optimised control law of the DC-link voltage depending on the motor frequency, on the traction torque reference and taking into account also the limit imposed by the catenary voltage. Calculation of the main power losses (MTF, PMCF, VSI, ASM) at different motor frequencies and torque demands (Handle). V dc = g 2 (ω m,t dem,v cat )

8 Control strategies for power losses reduction in high speed trains Figure 5: Route Chiasso-Shaffausen In the next figures the energy saving on a real SBB route Chiasso-Shaffausen is reported: It can be seen that speed limit is quite low so that the required power and torque are often limited.

9 Control strategies for power losses reduction CITHEL Platform Power scheme Motors Modules PWM patterns Electric Limits Nominal Effort/Speed Route profile Speed limits Train data Driving Cinematic Tool Speed Time Distance Effort Electric & Thermal Tool Kinematic data Electric data Thermal data Real Effort/Speed Curves The comparizons has been made using CITHEL (ALSTOM): Fast solver for iterative calculation of all steady state electrical and thermal curves and waveforms. Perform cinematic, electrical and thermal simulations on a real route (given the route profile and the driving data in order), to evaluate the energy consumption, the losses and the thermal behaviour.

10 Control strategies for power losses reduction Figure 6: DC Voltage and Motor losses

11 Control strategies for power losses reduction in high speed trains Figure 7: Original and optimized harmonic motor losses Figure 8: Original and optimized VSI losses

12 Control strategies for power losses reduction in high speed trains Figure 9: Original and optimized PMCF losses

13 Control strategies for power losses reduction in high speed trains EIn = (kwh) EIn T = 7342(kwh) EIn B = 897(kwh) EIn = 6295(kwh) EIn T = 7232(kwh) EIn B = 937(kwh)

14 Control strategies for power losses reduction: conclusion %Handle\frequenza 10 Hz 25 Hz 50 Hz 75 Hz 100 Hz 125 Hz 150 Hz 177 Hz 0% 7,95 8,96 16,13 32,84 36,54 59,86 59,06 54,49 25% 2,48 4,31 10,74 23,01 24,64 41,31 39,00 33,11 50% 1,63 3,94 9,96 13,43 17,28 23,35 16,38 11,16 75% 1,29 3,53 7,59 11,51 6,21 10,60 7,11 4,06 100% 1,07 2,90 5,17 4,64 1,89 4,53 3,05 1,90 The result of optimization is independent of the track. The algorithm is implemented in trains of the Swiss Railway System.

15 Ecodrive: speed tuning for energy saving in railway vehicles EXPO in Turin, 2014: report presenting measures in the route Rome-Civitavecchia Impact of the driving style of d ifferent drivers on the energy consumption. The difference can reach 50%!

16 Ecodrive: speed tuning for energy saving in railway vehicles Drive assistance (economy driving) Average energy reduction of 15%. No free driver reached the results obtained with the assistance of an economy driver

17 Ecodrive: speed tuning for energy saving in railway vehicles Data of the train, Line profile (slopes, speed limits, curves, etc...), Travel time, Position Speed profile (and driving style) optimizing the energy and satisfying the constraints

18 Ecodrive: speed tuning for energy saving in railway vehicles Dynamic equation (M s + M i ) dv ds = F T (v,h(s)) F B (v,h(s)) F R (v,s) F R (v,s) = A + Bv + Cv 2 + M s gtan(α) + G r c where M s =static mass M i =rotating mass s=position v=speed h(s)=handle F B =braking force r c =curve radius A, B, C = constants for friction: rolling, aerodynamic, damber hysteresis G =track gauge coefficient

19 Ecodrive: speed tuning for energy saving in railway vehicles Traction effort at various values of the handle!"#!"#!"#!#

20 Ecodrive: speed tuning for energy saving in railway vehicles Braking effort at h(s) = 1!"

21 Ecodrive: speed tuning for energy saving in railway vehicles Performance coefficient of the traction chain η(v, h(s)). S F T (v(s),h(s)) E L = 0 η(v(s),h(s)) ds, T = S 0 1 v(s) ds < T max, v(s) < v L (s)

22 Ecodrive: speed tuning for energy saving in railway vehicles mine L, h 1 (s) v(s) h 2 (s), 1 h(s) 1, E L,T A

23 Ecodrive: discretization of the handle h(s) = 0.5, h(s) = 0.75, h(s) = 1, h(s) = 1. Acceleration F T (v,h(s)) > F R (v,h(s)), F B (v,h(s)) = 0, h(s) {0.5,0.75,1} Cruising F R (v,h(s)) > 0 F T (v,h(s) = F R (v,h(s)), F R (v,h(s)) < 0, F B (v,h(s)) = F R (v,h(s)) Coasting F T (v,h(s)) = 0. Braking h(s) = 1,F T (v,h(s)) = 0.

24 Ecodrive: scomposition of the track and piecewise constant speed limits Figure 10: Eco-drive

25 Optimization on graph Sector 1 Sector 2 Sector Minimum path with time constraint

26 Ecodrive: speed tuning for energy saving in railway vehicles CITHEL Platform Power scheme Motors Modules PWM patterns Electric Limits Nominal Effort/Speed Route profile Speed limits Train data Driving Cinematic Tool Speed Time Distance Effort Electric & Thermal Tool Kinematic data Electric data Thermal data Real Effort/Speed Curves

27 Ecodrive: speed tuning for energy saving in railway vehicles Subway, 59.7 Km, 120 minutes, 43 stops, 215 ton, v max = 90Km/h, Line 750V Solution Duration Energy AllOut Cithel % % Ecodrive % % Table 1: Results: Subway

28 Ecodrive: speed tuning for energy saving in railway vehicles Tram, 28.4 Km, 85 minutes, 53 stops, 43.5 ton, v max = 70Km/h, Line 750V Solution Duration Energy AllOut Cithel % % Ecodrive % % Table 2: Results: Tram

29 Ecodrive: speed tuning for energy saving in railway vehicles Regional train, 33K m, 30 minutes, 10 stops, 92.7 ton, v max = 120Km/h, Line 3kV Solution Duration Energy AllOut Cithel % % Ecodrive % % Table 3: Results: Regional Train

30 Ecodrive: speed tuning for energy saving in railway vehicles Speed Limit Gradient [0/00] AllOut EcoDrive Speed Profile EcoMode Speed Profile Speed [km/h] Distance [m] Figure 12: Subway: Comparizon between speed profiles

31 Collaborative ecodrive

32 Distributed braking 0 σ 1 ( x) x 2 I C2 0 δ x P I C1 x 1 x 0 σ 1 F Cleaning effect: unknown! 0 σ 2 ( x) 0 σ 2 x x Delay Estimator in C1 Estimator in C2 σˆ1 RG RG = Reference Generator ˆ σ Σ Controller in C1 Controller in C2 Goal σ Σ i σˆi 0 ˆ0 σ ( x + δ 2 2 σ 1 σ 2 0 ) Dynamics of v v (anticipation)

33 Conclusions Working Challenges Modulation DC link Ecodrive Smart contactors Collaborative ecodrive (Alstom): Optimization TMS (traffic management system), exploiting synchronization of trains exchanging energy on the line. Collaborative control of the auxiliary devises (Microelettrica Scientifica). Smart grid control of converters. Stabilization of the output voltage of resonant converters through fast duty cycle compensation