Hardware in the Loop Qatar Nur-fuer-PDF

7/27/2019 Hardware in the Loop Qatar Nur-fuer-PDF

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Hardware-in-the-Loop Systems

With Power Electronics

a Powerful Simulation ToolProf. Dr.-Ing. Ralph Kennel

Technische Universitt Mnchen

Electrical Drive Systems and Power Electronics


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Simulation

Computer

Product

reference

values

real

values

(part of real world)


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Simulation

ComputerHardware


reference

values

real

values


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Simulation

ComputerHardware


reference

values

real

values

the Hardware,

of course,could be simulated

in the Computer

as well

this requires,

however,

exact modelling


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Simulation

ComputerHardware


reference

values

real

values

it is simplerto use the

real world

this requires,

however,

exact modelling


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Simulation

ComputerHardware


reference

values

real

values

it is simplerto use the

real world

especially

with respect to

the physical behaviour

ofenergy !


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Basic Idea : Virtual Machine

inverterunder test

this is the real world


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step 1


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step 2


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inverterunder test

machine

model

Basic Idea : Virtual Machine

this is the real world this is theHardware-in-the-Loop

System


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Outline

Introduction (Virtual Machine) Power Stage for High Switching Frequencies

Principle of Sequential/Interleaved Switching

Principle of Magnetic Freewheeling Control

Experimental Results

Control of Hardware-in-the-Loop Problems with Standard PI Control

Possible Solutions

Successful Machine Model

Summary


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Outline






Possible Solutions


Summary


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Outline






Possible Solutions


Summary

Requirements


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Requirementswith respect to the power stage

Virtual Machine must providebetter performance

than the inverter/device under test

to enforce any current referenceprovided by the model

higher switching frequency (> 50 kHz) slightly higher voltage UDC (> 750 V)


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Outline






Possible Solutions


Summary


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shar ing the swi tch ing losses

between several IGBTs in parallel connectionby switching them sequent ia l ly

Basic Idea of Sequential Switching

(1)

(1)

(1)

(2)

(2)(2)

(3)

(3)(3)


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sw i tch ing frequencyof each IGBT:

fIGBT =fparallel / n

n= number of IGBTs in parallel connection

switching frequencies:

f = 50...100 kHz



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reduction of the switching losses

by reducing the switching frequency

in each device

the devices are loaded with the full current !

limitation of the maximum switch-on time

to the cycle time of the system frequency

(pulse / pause = 33.3% max. for three IGBTs in parallel)


P bl F Wh li Di d


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Problem : Free Wheeling Diodes

f ree wh eel ing d iodescannot be switched

in s equent ia l order (act ively)

the following problems result from that :

all (!) free wheeling diodes are loaded

with the fu l l swi tch ing frequency

the diodeswith the lowest voltage dropheatmore than the others !! !

unsymmetr icload is increased parallel diodes

are not stable in operation !!!


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Outline






Possible Solutions


Summary

Basic Idea of Magnetic Freewheeling Control


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Basic Idea of Magnetic Freewheeling Control

Diode Current Measurement in a Half Bridge


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ode Cu e easu e e a a dge

with sequential Switching of Power Devices

UDC = 600 V

I = 25 Apeak

Comparison: 1 IGBT with f = 7 kHz and 3 IGBTs with f = 33 kHz


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Comparison: 1 IGBT with f= 7 kHz and 3 IGBTs with f= 33 kHz

UDC = 600 V

IL = 12 A

Inductance


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for Magnetic Free Wheeling

common core design separate core design

simpler, but bigger size

(not yet explored completely)

Bridge Branch with 5 Semiconductor Modules in Parallel


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g

Phase L1

M t f Di d C t d Di d V lt


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Measurement of Diode Current and Diode Voltage

(operation with 5 paralleled IGBT/diode modules)

UDC = 560 V

IL = 20 Apeak

sequential currents

in phases L1

of 5 paralleled inverters


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Outline Introduction (Virtual Machine)

Power Stage for High Switching Frequencies





Possible Solutions


Summary

Phase Current, IGBT Current and Diode Current


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(3phase operation with 5 semiconductors in parallel)

UDC = 560 V

IL = 20 Apeak

t

ms

Phase Current, IGBT Current and Diode Current


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(3phase operation with 5 semiconductors in parallel)

UDC = 560 V

IL = 20 Apeak

t

ms


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Control of Hardware-in-the-Loop

Problems with Standard PI Control

Possible Solutions


Summary


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Possible Solutions


Summary



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inverterunder test

machine

model

Problems with PI Control


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Basic Idea :

the current control of the Virtual Machine

is signi f icantl y fasterthan the control of the inverter under test

the control of the inverter under test

cannot react on the enforced current

Facts :a PI controller isat least with respect to its I componentnot fast (!)


is fighting against the control of the Virtual Machine


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Possible Solutions


Summary

T-Filter Between Inverters Instead of Inductance :


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inverterunder test

machine

model

Proposals


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p

T-Filter Between Inverters Instead of Inductance :

the current ofVirtual Machine is allowed to be differentto

the current of the inverter under test


does not fight against the control ofVirtual Machine

Disadvantages

T-Filter is more complex

than an inductance with parallel windings

the current ofVirtual Machine is not identical

to the current of the inverter under test

Proposals


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State Control Instead of PI Control

was proposed by the University of South Carolina(collaboration project with Schindler)

the state control ofVirtual Machine overrules


Disadvantages

optimisation/adjustment of state controllers is more complex

than optimisation of PI controllers

proposal is not suitable for small and medium sized enterprises

p


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Possible Solutions


Summary

Proposals


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Inverted Machine Model

in replacement of a model

calculating machine currents as a reaction on terminal voltages

a model is applied

calculating induced machine voltages as a reaction on

enforced machine currents



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input : current

output : induced voltage

output : rotor speed

Bisheriges Konzept


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Ls,s

original idea


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Ls,s

final idea

Proposals


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in replacement of a model

calculating machine currents as a reaction on terminal voltages

a model is applied

calculating induced machine voltages as a reaction on

enforced machine currents

Advantages

current controllers do not fight against each other

voltage sensors are not necessary at the output of the inverter under test !!

Measurements


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speed reversal

phase current

speed

Measurements


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speed reversal

phase current

speed

Measurements


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acceleration from standstill to rated speed at no load

quadrature current

speed

Measurements


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fast acceleration from standstill to rated speed at no load

stator currents ia, ib

stator voltage u

rotor flux

Measurements


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slow acceleration from standstill to rated speed at no load

stator current(s)

stator voltage

rotor flux

speed

Operation of the Machine Model


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input current, rotor flux, induced voltage at rated speed and low load

Measurements


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virtual load step

phase current

speed

Measurements


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virtual load step from 0% to 75% rated load at rated speed

quadrature current

speed

Outline


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Power Stage for High Switching Frequencies Principle of Sequential/Interleaved Switching



Control of Hardware-in-the-Loop


Possible Solutions


Summary


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Industrial Setup

VirtualMachine

Inverterunder Test

Summary


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in ter leaved sw itchin gis a basis to design power stageswith higher performances than usual

magnet ic f reewheel ing contro l

enables interleavedswi tch ingeven in the diodes

inver ted m achine modelavoids conflicts between current controllers

... and provides a scheme withou t vol tage sensors

inverter under test can be operated in the same wayas with a real AC mach ine

step1 step2 step 3


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Thank You !!!

Any Questions ?Prof. Dr.-Ing. Ralph Kennel

Technische Universitt Mnchen

Electrical Drive Systems and Power Electronics

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Hardware in the Loop Qatar Nur-fuer-PDF