Roll and control The AC 800PEC control platform in a broad range of applications Armin Eichmann, Andreas Vollmer

The great reliability, speed and precision required of power converters and drives call for high performance controllers. ABB’s AC 800PEC controller is integrated into the company’s successful and widely adopted 800xA control system. The AC 800PEC is suitable for a wide range of applications – not limited strictly to power electronics control, but including fields such as rolling plants in the metals industry where it is has a part in controlling the complete process. The following two examples illustrate the successful integra- tion of the AC 800PEC1) in locomotive drives and rolling plants.

Fast control in a telland). All these trains are manufac- er converters are all controlled by tured by Stadler Rail AG. Since their AC 800PEC units from ABB. traction application first commercial operation in Decem- ber 2003, a total of about 250 vehicles System Configuration To lower operating costs while raising have been commissioned. Their pow- The CC750® was developed as a trac- attractivity, modern trains are becoming increasingly light and agile. The on-board power converters must 1 ABB’s CC750® power converters are an integral part follow suite by delivering greater of the FLIRT-type modern lightweight trains. speed, responsiveness and reliability while fitting into a smaller footprint. Enter ABB’s CC750® power converter!

he CC750® low-voltage IGBT con- Tverter is at the heart of the power circuit of the FLIRT 1 type2) [1] of (SBB) as well as of GTW-type vehicles for the oper- ators THURBO (-Bodensee Bahn) and RM (Regionalverkehr Mit-

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tion converter for use in regional and 2 Traction converter arrangement on THURBO GTW with two CC750® units delivering a total of suburban electrical multiple unit 1.1 MW of traction power. trains. The CC750® has an integrated auxiliary supply and is suitable for a pantograph (15kV, 16 2/3 Hz cantenary) i traction inverter (480V / 0 – 170 Hz, several catenary voltage supplies in- b main circuit breaker 750 kVA traction power) cluding 15 kV / 16.7 Hz and 25 kV / c transformer j and k asynchronous traction motor 50 Hz. It uses IGBT (Insulated Gate d and e CC750® power converter units l three-phase auxiliary supply Bipolar Transistor) modules with f auxiliary transformer winding for train (50 kVA / 3 x 400 Vac) 1200 V blocking voltage in both its heating supply m battery charger (12 kW / 36 Vdc) traction supply circuit and in the g grid inverter (390V input) n brake chopper auxiliary converter. h DC-link (750V)

The two converter systems are fully redundant – the vehicle can continue to operate at reduced power should one of them fail. a

The main system configuration is shown in 2 . Two identical CC750® b 2d 2e d e converter systems ( and ) are con- l 2a c nected to the catenary via a com- m mon oil-cooled high voltage trans- n former 2c . The two converter systems h j are fully redundant – the vehicle can k continue to operate at reduced power f g i should one of them fail.

Embedded Control System A decentralized concept was chosen for the control hardware 3 consisting of the following units: AC 800PEC Controller 3e , ABB’s In order to ensure high tolerance to 3 Control hardware panel of CC750® high-end process control system. electromagnetic interference, commu-

This can be programmed using nication between the AC 800PEC Con- a auxiliary module ® ® MATLAB /Simulink and Real-Time troller, the PEBB interface board and b PEBB interface board ® Workshop . the Combi I/O board is assured by c Combi I/O board 3b The PEBB (Power Electronics optical fibers. An additional optical d auxiliary module Building Block) interface board, link connects the converter control e AC 800PEC used as a universal remote I/O de- system to the higher level vehicle con- vice. This board controls and pro- trol system via a CANopen bus. The tects the IGBT converters. The connection to a host computer for links to the IGBT drivers are bidirec- programming and monitoring purpos- a tional. es is provided by an Ethernet link. Combi I/O board 3c , a universal remote I/O device for high-speed Since December 2003, a traction applications. Auxiliary modules 3a 3d , comprising total of about 250 vehicles power supplies and intermediate have been commissioned. current and voltage transducers and b c the control of the switch and dis- Their power converters connector devices. are all controlled by AC 800PEC units from ABB. Furthermore, the hardware arrange- d ment includes AC current and DC voltage measurement (synchronous Control Software of the AC 800PEC e sampling), overcurrent protection and High-speed digital control systems rep- modulation and firing interlocking. resent the state of the art in power

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electronics. Typically, FPGAs tion level favored by control Table 1 Software tasks and their cycle times (Field-Programmable Gate and system engineers. All cod- Arrays) using advanced ing, downloading and monitor- tasks (examples) cycle time VHDL (VHSIC Hardware ing functions are integrated into Vehicle Control speed and torque 50 ms Description Language) pro- the platform. The engineer is via CANopen instructions gramming tools are used spared time-consuming and AC 800PEC, Task C state machine, 1 ms for highly time-critical func- MATLAB®/ slow protection error-prone low level coding. tions in the microsecond- Simulink® flux controller range and below. In the with Real-Time Control systems typically consist intermediate speed range Workshop® Task B current controllers, 250 μs of components with different (100 µs to millisecond-range) pantograph time constants. The software AC 800PEC provides a soft- bounce detection therefore has sub-tasks that are ware layer based on MAT- Task A very fast current 50 μs executed at different intervals. ® ® LAB /Simulink with Real- controllers In the control software for the Time Workshop® [2]. This FPGA, VHDL modulators, ns-range CC750®, three software cycles environment allows high- very fast have been implemented run- level graphical programming protection ning at cycle times of 1ms, on the conceptual abstrac- 250 ms and 50 ms Table 1 .

n hot and cold rolling mills 4 , the level binary control up to advanced Rolling mill in the Idemands on mill profitability, pro- and sophisticated control solutions. metal industry ductivity and product quality are on The AC 800PEC is outstandingly well the rise. At the same time, mill flexi- suited to meet these requirements. bility has to match the growing variety Beside the full integration into the In the metals industry, demands on of products. Strip quality and mill 800xA Automation platform with com- product quality and on plant produc- throughput are influenced by various munication to I/Os, Drives, various factors such as mechanical design, fieldbus systems and the Human tivity and flexibility are steadily in- electrical equipment, auxiliary sup- Machine Interface, its strengths lie in creasing. ABB’s new generation of plies and control strategy, and the its powerful programming capability rolling mill automation system in- very many associated variables have (based on IEC 61131-3) and the CPU cludes an integrated and advanced to be tightly controlled to meet prod- performance provided 5 . solution suite that meets the custom- uct quality targets. ers’ needs for product quality and The customer’s benefit is throughput. The use of ABB’s 800xA An impression of key data of a cold rolling mill is given by Table 2 . To be an improvement of the Automation Platform with the power- able to control such a large and com- ful AC 800PEC controller permits mill- thickness deviation of up plex plant and meet the high demands wide uniform automation, seamlessly on process speed and product quality, to 50 percent (product integrating advanced solutions into a powerful controller is needed to dependent). the process control system. handle all required functions from low

The most demanding function in a 4 Everything under control at the rolling mill rolling mill is the thickness control. Keeping the strip thickness within a narrow tolerance band is one of the

Table 2 An impression of key data of a cold rolling mill

Maximum roll force = 30 MN Maximum mass of rolls in a stand = 40 tons Maximum mill acceleration = 2 m/s2 Maximum mill speed = 150 km/h Minimum strip thickness = 6 µm Thickness tolerance = 0.5 ... 1.0 %

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do not fully take into account the con- 5 Typical system configuration of the rolling mill application nection between thickness, roll posi- tion and tension [3]. OperateIT & MES Server Computer room Main control room By using the powerful AC 800PEC Flatness Thickness controller and its possibility of imple- menting C-Code beside the standard IEC 61131-3 program level, a new thickness control solution for cold MMS, TCP/IP rolling mills has been developed based on a MIMO (Multi-Input Multi- Output) control concept. The custom- DriveBus er’s benefit is an improvement of the ... thickness deviation of up to 50 per- cent (product dependent).

• Entry section and coil • Presetting & • Roll force • Flatness Mill flexibility has to match preparation recording control control • Exit section and • Master refer- • Position the growing variety of spool handling, ence control control products. coil transportation • Coiler, mill • Thickness • Mill stand section and drive and control roll change Deflector roll • Tilt control A powerful all-rounder • Hydraulic, lubrication control • Roll bending Thanks to the different programming & roll oil and shifting levels of the AC 800PEC, this control- ler is well suited for a broad range of applications – from fast control algorithms in power electronics to process-wide control applications.

6 MIMO control concept with dynamic online parameter adaptation

Pass schedule, set-up and adaptation Control Set point Parameters Armin Eichmann objectives ABB Ltd. Controller Turgi, Switzerland On-line plant model design/adaption [email protected]

Controller On-line Andreas Vollmer parameter estimation ABB Automation GmbH MIMO Dynamic Mannheim, Germany controller disturbance FF [email protected] Mill Dynamic PIDs decoupler References [1] Peter Bruderer Stadler Rail Bussnang, Description of FLIRT train, Railvolution 4/04 pages 58–72 [2] The Mathworks, User Manual Release 12.1, In particular Matlab, Simulink, Real Time Workshop, Stateflow, Stateflow Coder mill’s most crucial requirements. The of the rolling process, mechanical, [3] ABB in metals, http://www.abb.com benchmark is set by the deep draw- electrical and hydraulic systems, in- ing3) of aluminum and steel sheets strumentation, as well as the lubrica- Footnotes for cans or car body parts. The more tion and the control strategy must all 1) For more background on the AC 800PEC, see also the variation of thickness can be fit together seamlessly 6 . “Design patterns” on page 62. 2) reduced, the smaller the minimum FLIRT: “Flinker Leichter Innovativer Regional Trieb- zug” or “Fast, Lightweight Innovative Regional permissible thickness the mill can be State-of-the-art thickness control algo- Train” operated at. This permits improve- rithms are composed of single feed- 3) Drawing is the process of forming metal sheet into ments through lower material usage, forward control loops. These algo- cylindrical or box-shaped parts using a punch. In weight saving and overall cost-effi- rithms are limited in their achievable deep drawing the depth of the part is greater than ciency. To achieve effective control thickness performance because they its diameter.

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