Embedded to Power Electr

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Procdings of th 2ndntrnationa Confrnc on nforation Tchnoo, CT200 28-30 Jun 200, Gdans, Poand

Flexible Embedded Control System Architecturefor Power Electronics Applications

z wThe Electrotecnical Institute

he Gdansk BranchGdansk, Poland

[email protected]

Abstract-The paper presents a new exible architecture of anembedded control system for power electronics applications. Thehardware part of the system is divided between a CPU module

and a baseboard dedicated for target system arrangement,

depending on application requirements. Flexibility of thecongration was achieved by using DSP/ARM/CPLD/FPGAcomponents. The development line of unied CPUs and a

baseboard family for various power converter topologies and

applications is introduced. Some research, educational andindustrial applications are briey presented and discussed.

Keywo: powe ovee ool yem DS FG

NTRODUCTION

Embedded contl systems bsed on miroprocesor andprogramable logic devices re oen applied in the brnch ofindustrial electronics,especially power electronics. Stndardapplication reas of mode power electronics are continuouslyextending volume and quality, e.g. variable speed drives,active lters, power conditioners and power supplies. Newemerging product groups are cuently under development:electric vehicles and railways [], fast battery chargers, powersupplies, photovoltaic and wind energy conversion systems.

A control system is one of the ajor pars of any powerconverer. A controller must suppor power converter hardwaretopology and provide n adequate computing power necessaryfor real-tie algorithm iplementation. The design process ofreliable control systems for advanced power converters is timeconsuing and ust follow the techology progress inmicrolelectronics.

A exible architecture of a digital control syste is

proposed for rapid prototyping and a target application supportin power conversion and intelligent motion control reas. Thesystem is based on an extended set of integrated ccuitsdedicated for signal processng and digital logic function orperipherial blocks arrangement: digital signal processors(DSP), AR microcontrollers and programmable logic devices(CPLD, FPGA). During last decade DSPs were standardsolutions for real-time control. Currently ARM-basedmicrocontrollers and eld programmable gate arrays achieve acompetitive technology grade.

II. FLEXIBLE RCHITECTURE O ONTROL YSTEM,CPU ODULES

The new approach is based on a exible conguration

which consists of a versatile central processing unit (CPU) andbaseboard suited for target application requireents.

Scalable computational power and I/O blocks of the CPUscan meet various requreents of power conversion and motioncontrol algoritms. A suitable CPU module can be specieddepending on user's programing experiences and application.It must be also equipped with a dedicated interface fordownloading, executg and debugging user programs n a

trget syste using specialized development and codegeneration tools.

Th t membe nw CPU family is ad on ghspeed TMS320F2812/2812 digital signal processor (Fig. 1,2)The teal structre of the TMS320F2812 processor includes

the following major blocks: a 128K16-bit FLASH meory,18K6-bit inteal RAM, boot ROM with selectable sowreboot modes and standard math tables, 16 PWM chaels withdead-time generators, 2 incremental encoder interfaces, 12-bitAD converer with 28-chael input multiplexer nd 2 S/Hunits. The TMS3202812 has no an nteal FLASH memoryand has a 20K6-bit RAM only. In standalone operation theprocessor must boot the user program om an extealEEPROM.

igure 1. Hig-seed 32-bit xed-oint CPU modue DLH2812

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igure 2. High-seed 32-bit xed-oint CPU modue DLH2812

The man exteal signals of a plug-in CPU are arrangedinto two connectors with standrized pinout topologies: analoginputs for I/U transducers, control (PWM) and diagnostic(ERROR) signals and data transmission signal/power supplies.

Sophisticated power electronics applications, especiallnew R&D projects, require increased speed and computing

power of the control sstem. The CPU famil must follow thetechnological trends. Contuous development andimprovement are requed. New CPU concepts are focused onadvanced oating-pont DSPs (TMS320F2833x, Delno,Shrc) and ARM processors. High-speed FPGAs (Cclone,Stratix, Spartan, Vtex, Fusion) can be also used as a maprocessor with parallel processing capabilities (Fig. 3).

igure 3. Mixed-signa PGA-based recongurabe CPU modue

III. FLEXIBLE ASEBOARDS OR OWER LECTROICS

The exible baseboard famil was designed to be easilapplied for a wide range of power conveter topologies. Theinteal architecture of a exible baseboard consists of thefollowing major blocks: a programmable logic unit based on ahigh-speed CPLD with the capacit of 5701270 logical blocksand in-sstem programming capabilit, 2 exible interfaces forwer inverer ontrl and dianostc (6 PWM outpt nd 4diagnostic inputs), 12 analog inputs for voltage/currenttransducers, 2/4 analog ouuts (81012-bit, 03V), 2incremental encoder inputs (A, B, INDEX signals), 2 rela

outputs (250VA8A), USB nd CAN terfaces,16/32/64128kB serial EEPROM or FLASH memor, real-timeclock (R TC) with batter backup, power suppl and sstemsupervising unit (Fig. 4, 5).

190

IUSBI lB

igure4. exibe baseboard for ower eectronics aicatons bockdiagram of standd version

gr 5. ebe basebard for r eectroics tndd rson

All exteal digital I/O signal of the baseboard are equippedwith galvnical isolation based on high-speed optocoplers(015MHz). A higher switching speed (up to 150MHz) can besuppoed b new generation of isolators with magnetic orcapacitive couplng.

Flexibilit of the baseboard famil is achieved using aCPLD chip. Almost all digital I/O signals cn be routed to/omselected pin of the man processor b a user-dened switchgmatrix. Advanced pre-/post-processg of processor signals isalso available inside the CPLD structure. Each PWM signal canbe supplied om a PWM line of the main processor or sourcedom a CPLD pin on the baseboard depending on the userselection (Fig. 6).

igure 6. exibe PWM signa generation bock


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Simple/complex PWM signal correction/generation can bearranged inside the CPLD (Fig. 7,8, 9).

CLCLK- APWy + l

HDdtm PW

WMx APWMy r nt Dit + . .

igure 7. Sime digita bock for PWM signa correction

oc INT .

blk

A,LCKPy + mePWMy g . u k 1 8 .

I - IS;

: . "C' , t

igure 8. Comex digita bock for PWM signa generation with ae bus

ERROR

asblk

-e

igure 9. Comex digita bock for PWM signa generation with seria bus

IV. ApPLlCAONS

An architecture of the exible control system can becongured for many power converer strctures. It can besuccesslly applied in the reserch, educational and industrialareas.

A Rsarch AppicationsSupercapacitors (supercaps) give new possibilities for electric

energy storage and power conditiong. Industrial system faultshave been oen caused by shor-term network voltagedisturbances. It makes possible to replace traditional batebased UPSs by power conditioners with supercaps. The newequipment can provide fast response d recovery time withoptional active ltering. Matenance costs can be signicantlyreduced. The Gdansk Branch of the Electrotechical Institutehas maged the special R&D project of a high-voltagesupercap-based three-phase power conditioner [2]. Each phasehas a similr structure of the power stage and a separate DSPcontroller (Fig. 10,II).

L1 F

LOA

N

igure 10. Power conditioner schematic diagram of singe hase

igure 11. 3-hase ower conditioner rototye

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Multilevel current inverer strcture analysis and controlalgorit development were proposed as a new Ph.D project[3]. 3-phase outputs of tee power inverers are connecteddirectly in parallel without any coupling transformer. A exiblecontrol system with an extended baseboard is used to manageup to 18 power switches (Fig. 12, 13).

igure 12. Mutieve current inverter schematic diagram of ower circuits

igure 13. Mutieve current inverter exerimenta setu

B Educationa Appications

The exible control system architecture is well optimized forcomplex AC/DC/AC converters topologies. A precisionsensorless AC ive system (Fig. 14, ) with bidirectionalenergy ow has been designed by a research team of theInstitute of Electrical Machines, Drives and Measurements(Wroclaw University of Tecnology, Poland). Anothereducational application of the exible control system has beendeveloped at the Institute of Control and Industrial Electronics(Warsaw Institte of Technology, Poland). The current invererdesign was based on SiC power switches [4]. High-speedvector pulse-width modulation algorits were implementedusing coupled DSP/CPLD hdware.

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igure 14. Precision motion contro system with ACC/AC converter

igure 15. Precision motion contro system aboratory setu

C ndustria AppicationsThe presented exible control system was adapted and

successlly applied to upgrade traditional DC drives n fourPolish integrated metropolit trains EN-7 (Fig. 16, 17). Newdrive systems ncludes high-voltage IGBTs (6.kV) and a DSPbased CPU module which enables rapid prototypng,implementation and testing of improved motion controlalgorits.

igure 16. Metrooitn train EN-57 with motion contro system ugrade


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Figure 17. DSP-based motion control system for EN-57

The cuent development works e focused on a newadvanced design of motion control, diagnostic and an auxilirypower supply system for the new prototype of a heavy electric

locomotive E6ACT (Fig. 10). It features a 6-axis motionsystem with 5 MW asyncronous motors. Each axis/motor paris supplied om a separate equency converter, therefore threeexible control systems must be used for this project.

Figure 18. Heavy electric locomotive E6ACT prototype with DSP controlledhigh-power AC drives

Both presented industrial projects were made by ElectricTraction Depment of the Electrotechnical Institute. It has

been involved development of electric and electronicsolutions for a wide range of electric traction vehicles (e.g.locomotives, integrated trains, trams, trolleybuses and electriccars).

V. ARDWARE ESTING

AND UTURE EVEOPMENTSAn advanced test bench for automatic setp and diagnostics

of the exible control system is currently under development. Itconsists of hardware (JT AG emulator, simulation andmonitoring modules) and soware pars (testing andvisualistion soware modles for the target system and PCplatform). The industrial versions of the system dedicated forrailway applications are additionally tested a thermalchamber and also according to EMC.

It is expected that ecient usage of limited energyresources coupled with increasing environment protectionrequirements will become more important. Combustionengines are prognosed to be replaced by high-eciency

electric motors (AC, PMSM). Except motors and drives,power supply systems of electric vehicles can includefunctional blocks (batteries, super capacitors, ell cells)which require efcient intelligent power management units.These applications will dene future development works.

EFERENCES

[] M. Frohlich M., "Technology Trends in Railway Traction. In:Proceedings of the Inteational Conference for Power Electronics,Intelligent Motion, Power Quality. PCIM 2009, May 12-14 2009,Nuberg, Germny.

[2] P. Bogusawski , E. Lowiec, "Wielopoziomowy kompensator napicia zsuperkondensatorowym zasobnikiem energii wybrane aspektykonstrukcyjne, Prace Instytutu Elektrotechniki, Zeszyt 239'08,Wszawa, Poland, 2008.

[3] L. Wolski, "Wielopoziomowy falownik prdu" Prace InstytutuElektrotechniki, Zeszyt 227'06, Warszawa, Poland, 2006.

[4] M. Andrzejewski, 1. Rbkowski, "Modulator dla falownika prdu PWMo podwyszonej czstotliwoci implementacja w procesorzeTMS320F2812" VII Ognopolska Konferencja Naukowo-Techniczna"Postpy w Elektrotechnice Stosownej (PES-7), Kocielisko, Polnd,2009.

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