Update on Conventional and Gearless Drive Systems for Draglines Industrial Solutions and Services Your Success is Our Goal

Transcription

1 61 st MEMSA Annual Meeting September 7, 2006 Walter Koellner / SE&A Mark Johnston / Bucyrus International Update on Conventional and Gearless Drive Systems for Draglines Industrial Solutions and Services Your Success is Our Goal

2 Table of Content History and Barriers for Static Dragline Drive Systems W Major Components Motors, AFEs, Inverters W Power Factor Control and Harmonics Methology W Slide Show from 8750 Erection at Zhungeer, China W,M

3 History and Barriers for Static Dragline Drive System Draglines with M-G set drives are in operation for nearly one century Evolutionary upgrades with analog and digital controls Reliable operation but limited with respect to efficiency, productivity, maintenance and operating costs Compliance with utility requirements on voltage fluctuation at the PCC and harmonics was major barrier for static DC or AC systems on large draglines. This can be overcome for the first time in history with AFEs (Active Front End rectifiers) In addition there is the option to install Gearless AC Drives for the Hoist and Drag or Conventional AC Drives with gears replacing the DC motors 1:1

4 Major Components AC Motors Gearless synchronous for Hoist/Drag, induction with gears for Swing, Propel AC Induction Motor replaces DC Motor 1 : 1

5 Major Components AFE / Inverter Active Front End Rectifiers (AFEs) provide leading Power Factor just like M-G sets before. This makes Static Dragline Drives for the first time in history feasible. Water cooled IGBT (Integrated Gate Bipolar Transistor) Inverters use same technology as BI excavators and haul trucks Proven, reliable traction power and control hardware (SIBAS)

6 AFE Fundamentals Power Circuit CT's IGBT Modules and Internal Diodes R S Line Reactors R + (Upper) S + (Upper) T + (Upper) Three phase AFE Power circuit T R - (Lower) S - (Lower) T - (Low er) AFE 3 Phase Diagram

7 AFE Fundamentals AFE Single Phase Diagram #1 L1 S1 D1 D3 S3 + - Line = 900 vac =1272 peak L2 S2 - D2 Bus 1800 VDC + D4 S4 Positive Half-Cycle: Initial State: All Switches Open

8 AFE Fundamentals AFE Single Phase Diagram #2 L1 + - Line = 900 vac =1272 peak S1 D1 - D3 + S3 - + L2 S2 D2 Bus 1800 VDC D4 S4 Positive Half-Cycle: Initial State: All Switches Open S1 & S2 Close--Causing a large current flow through L1 & L2.

9 AFE Fundamentals AFE Single Phase Diagram #3 L1 S1 D1 D3 S3 + - Line = 900 vac =1272 peak L2 S2 - D2 Bus 1800 VDC + D4 S4 Positive Half-Cycle: Initial State: All Switches Open S1 & S2 Close--Causing a large current flow through L1 & L2. S1 & S2 Open--L1 & L2 try and maintain the current flow in the Same Direction. the Voltage rises above 1800 volts, there is a current flow through D3 & D2 As

10 AFE Fundamentals AFE Single Phase Diagram #4 L1 - Line = 900 vac =1272 peak S1 D1 - D3 + S3 + L2 S2 D2 Bus 1800 VDC D4 S4 Negative Half-Cycle: Initial State: All Switches Open S3 & S4 Close--Causing a large current flow through L1 & L2. The Current is in the opposite direction compared to the positive half-cycle. S3 & S4 Open--L1 & L2 try and maintain the current flow in the same Direction. As the Voltage rises above 1800 volts, there is a current flow through D4 & D1

11 AFE Fundamentals Control Circuit V* dc V dc I* d + - I d V d Vector Modulator Firing Pulses I* q (for P.F.=1) + - V q I q Simplified control system

12 AFE Fundamentals Motoring: The AFE supplies VARs to the line depending on the inverter voltage amplitude V x V x V x V L Line V inv X L DC AC AFE Power Flow + V X - ( Motoring ) ( Regen ) V DC V L V L I 1 V inv V L V L V inv V inv V inv I 1 Motoring, Leading P.F., AFE supplies VAR to line I 1 Unity P.F. I 1 Lagging P.F. VAR are controlled by inverter voltage amplitude = modulation = excitation

13 AFE Fundamentals Staggered Operation In staggered mode the 24 AFE s are syncronized with the firing pulses shifted by 1 degree ( PP15, 24AFEs=360/15/24 ) Result:24x900 Hz=21.6KHz effective switching frequency and lowest THD V 1 P.F. I afe V * dc + V dc - PI voltage + + Feed forward I dc ref Load Sharing and reference generation I * d1 I * q1 I * d4 I * q4 I d1 Control I afe1 PI + Feed forward + decoupling I q1 Control I afe4 d,q abc Vector modulator V dc V * dc P inv PI + Feed forward + decoupling d,q abc Vector modulator I d4 I q4 Control system for staggered AFEs

14 IGBT Inverters IGBT (Integrated Gate Bipolar Transistor) Inverters Common Technology with BI Excavators & Trucks Reliable Traction control system Enhanced Diagnostics and Maintenance Support Water-cooled IGBT Phase Module same for AFE and inverter Proven, Reliable Technology

15 IGBT Advantages IGBT's utilize simple, reliable, gate drivers without snubbers and di/dt reactors IGBT's can safely turn-off overload currents without damage (GTO's fail if overloaded even momentarily) High switching frequency means smoother currents Water cooled or air cooled NO Fuses

16 Inverter Cabinet Dragline

17 Inverter Cabinet Dragline

18 Single Line Diagram Hoist / Drag

19 P.F., Harmonics - Methodology of Analysis 1. Create single line diagram of distribution system and loads 2. Convert to per unit values 3. Create condensed single line diagram for analysis 4. Set voltage level at PCC to 1 (100%) with new dragline off and all other loads present 5. Study voltage fluctuation at PCC and other network points with new dragline peak motoring and generating loads. 6. Define leading PF for motoring and generating loads which reduces the voltage fluctuation at PCC to 0.1% (1.001, 0.999) 7. Define THD created by the dragline drive system 8. Expand model with line and other capacitances and check for resonance frequencies.

20 Example to Create single line diagram of distribution system and loads

21 Example to 2., Convert to Per Unit Values kva base = 100,000 kva kv base = 110 kv 3. Create condensed single line diagram for analysis V0 V1 V2 V3 V4 V5

22 Example to Set voltage level at PCC to 1 (100%) with new dragline off and all other loads present

23 Example to 5., Define leading PF for motoring and generating loads which reduces the voltage fluctuation at PCC to 0.1% (1.001, 0.999) 22MW motoring pf = V1 pu V5 pu

24 Example to 5., Define leading PF for motoring and generating loads which reduces the voltage fluctuation at PCC to 0.1% (1.001, 0.999) 13MW regeneration pf = V1 pu V5 pu

25 Example to Evaluate Voltage Swing at PCC over complete duty cycle DUTY CYCLE 0.1 m x x 54

26 Example to Evaluate Voltage Swing at PCC over complete duty cycle w/o auxiliaries DUTY CYCLE 1 V0 pu ( x) 0.97 V1 pu ( x) V5 pu ( x) x 54 maximum minimum delta V1 pu V5 pu

27 Example to Expand model with line and other capacitances and check for resonance frequencies.

28 Example to THD and harmonic spectrum at primary of MPT on dragline 1.17%

29 Example to e.g. 23 rd harmonic produces 20% resonance

30 Photos 8750 Erection Zhungeer, China