A DC-link Voltage Estimation Based Active Damping Control

A DC-link Voltage Estimation Based Active Damping Control Method of Single-phase

Reduced DC-link Capacitance Motor Drives

Nannan Zhao, Harbin Institute of Technology

1

I received the B.S. and M.S. degrees in control scienceand engineering in 2013 and 2015, and the Ph.D. degreein electrical engineering in 2019, all from Harbin Instituteof Technology. Currently I am a Postdoctoral Fellow and aLecturer in the School of Electrical Engineering andAutomation, Harbin Institute of Technology. My currentresearch interests include advanced control of permanentmagnet synchronous motor drives and position sensor-less control of ac motors. I am a member of IEEE andcurrently supported by Postdoctoral Innovative TalentSupport Program of China

Nannan Zhao

2

Impedance model of IPMSM

Drive system performance evaluation

Experimental Results

Introduction

Drive system impedance model

A DC-link Voltage Estimation Based Active Damping Control Method of Single-phase Reduced DC-link Capacitance Motor Drives

Harbin Institute of Technology, Nannan Zhao 3




Introduction



4Harbin Institute of Technology, Nannan Zhao

Electrolytic capacitor Short lifetime Large volume Need PFC circuit

inu

1D 2D

3D 4D

2S 3S

4S 5S 6S

1S5D

V

sL

IPM

Film capacitor High reliability Small volume Without PFC circuit

Introduction

IPMgu

3S2S1S

gL

4S 5S 6S

1D 2D

4D3D

dcC

Topology analysis


Introduction

[10ms/div]

[5A/div]gi

dcu

[2s/div] [5A/div]mi

gridi

LC resonance Obvious grid current harmonics Drive system stability

Beat phenomenon Obvious grid current harmonics Drive system stability

Practical issues


Stator currentharmonics

Harmonicscaused by LCresonance

Grid side performance

Grid current analysis

ini

dci

invi

g dc invi i i= +

Conduction angleof diode rectifier

Grid currentharmonics

Flux weakeningcurrent

back electromotiveforce

IntroductionGrid current performance improvement

Grid current


Stator current suppression loop

Repetitive controller of specified frequency

Harmonics caused by stator currents

IntroductionGrid current performance improvement

back electromotive force

Time[s]

Volta

ge[V

]

Grid side resonance information detection

Power exchange between line inductor and film capacitor

Voltage and current command

Harmonics caused by LC resonance


Drive system characteristic equation:

IntroductionLC resonance suppression method toenhance drive system stability

Stability control methods:

Nannan Zhao

L gL2 2

d

g2

g g dcc dc,0 dc,0

1( ) (1 ) 0P RP

C u uR

s sL L C

+ + − =−

Change coefficientsIncrease positive term

Reduce negative term

Virtual impedance controlVirtual capacitance

Virtual resistance

Power coupling characteristic

dcugucapi invi

dampR

gLgR

gi

dcC

Virtual resistor based stability control method

abu

dcu

ini

小容值薄膜电容

inP dcP invP

电机

9

IntroductionDrive system equipped with small line inductance

3S

2S

1S

gL

4S

5S

6S

1D 2D

4D3D

dcC

gU

Drive system with small line inductance

ci

dcC eqR

1D 2D

3D 4D

gi

gL

invi

gU

Resonance characteristic analysis


IntroductionDrive system characteristic analysis

ci

dcC eqR

invi

dcu+

−

gR

( ) g

g g g g g dc1

g c inv

dc1c dc

eq inv dc1

sindi

U t L R i udt

i i idui C

dtR i u

ω δ

+ = + +

= + = =

dc2c dc

eq inv dc2

c inv 0

dui Cdt

R i ui i

=

= + =

LC resonance occurs Discharge process

Forward-biased mode Reverse-biased mode


IntroductionDrive system characteristic analysis

As line inductance decreases:

the LC resonant frequency increases

the magnitude of the resonant DC-linkvoltage decreases

Make it more difficult to suppress theLC resonance

025

10

220

Mag

nitu

de (V

)

20

1.515

30

110 0.50

Magnitude of DC-link voltage





Introduction




Impedance model of IPMSMImpedance model construction

e q qL iω

sRe fωψ

qL

e d dL iω

di

qi

gLgi gR

invisR dL

sudcu

du

qu

d d,0 drefdc

q q,0 qrefdc,0

= +u u uuu u uu

∆ ∆ ∆ ∆ ∆

Drive system model

( ) d,0 e d q,0 d d,0 d,0inv,0 d,0

m 2dc,0 dc,0 s d d

q,0 q,0 e q d,0 q q,0 q,0 s2dc,0 s q q

32

32

su L i L i s i Ri us

u u R L su u L i L i s i Ru R L s

ω

ω

+ + += − +

+ +

− + ++

+ +

YG

G

( )

2g dc g dc

LCg g

1L C s R C ss

L s R+ +

=+

Y

( )dc inv d d q q32

u i u i u i= +

Inverter power：

Motor admittance：

LC filter admittance： Small signal of motor voltage：





Introduction




Drive system impedance modelDrive system characteristic analysis

e q qL iω

sRe fωψ

qL

e d dL iω

di

qi

gLgi gR

invisR dL

sudcu

du

qu

Drive system model

Grid input impedance：

( ) ( )( )1

mg g g

m dc

Z sZ s L s R

Z s C s= + +

+ ⋅

Grid input impedance with different DC-link capacitance





Introduction




Drive system performance evaluationDrive system performance evaluation

Resonant DC-link voltage estimation：

Grid input impedance before applying the proposed

control method

2

2 2

22

g BPF gdcr

BPF BPF

K i su

s sξωξω ω

=+ +

where Kg and ωBPF are the feedback gain and the bandwidth of the band-pass filter

Apply udcr to q-axis voltage:

( )( ) ( )

( )

,0 ,0 ,0 ,01

,0-1

,0 ,0 ,0 ,0

,0

32

=312

q e q d q q q sdc dcrm

dc g s q qmad

q e q d q q q sdcr

dc g s q q

u L i L i s i RsC uZ su i R L s G s

Z s u L i L i s i Ruu i R L s G s

ω

ω

− − + +

+ + + − + +

−+ +

increases

-180

Frequency(rad/s)

Phas

e(de

g)

-90

90

360

Mag

nitu

de(d

B)

020

40

60

increases

-60

0

270180

-20

-40g 1.0mHL =g 0.8mHL =g 0.5mHL =

g 0.05mHL =

g 0.2mHL =

g 0.1mHL =

110 210 310 410 510 610

gL

gL


Drive system performance evaluationDrive system performance evaluation

Nannan Zhao

Grid input impedance after applying proposed method

-150 -100 -50 0 50 100 150 200 250 300-400

-300

-200

-100

0

100

200

300

400

Real Axis

Imag

inar

y A

xis g 0K =

g 0.002K = −

g 0.004K = −

g 0.006K = −

g 0.008K = −

g 0.01K = −

-1.2 -1.15 -1.1 -1.05 -1 -0.95 -0.9 -0.85 -0.8-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Real Axis

Imag

inar

y A

xis

g 0K =

g 0.002K = −

g 0.004K = −

g 0.006K = −g 0.008K = −

g 0.01K = −

Unstable

Stable

Stable

Stable

Stable

Stable

-40

-20

0

20

40

60

Mag

nitu

de (d

B)

Kg

=0

Kg

=-0.002

Kg

=-0.004

Kg

=-0.006

Kg

=-0.008

Kg

=-0.01

10 1 10 2 10 3 10 4 10 5 10 6-180

-90

0

90

180

270

Phas

e (d

eg)

Frequency (rad/s)

gK increases

Impedance increases

Nyquist plots after applying proposed method 19




Introduction




Experimental resultsExperimental platform

Grid input impedance after applying proposed method


Experimental resultsDrive system performance results

With proposed methodWithout proposed method

[100

V/d

iv]

dcu[5

A/d

iv]

gi

[10ms/div]

mi[5

A/d

iv]

Harmonics caused by LC resonance are obvious

[100

V/d

iv]

dcu[5

A/d

iv]

gi

[10ms/div]

mi[5

A/d

iv]

Harmonics caused by LC resonance are mitigated

(b)

0

0.2

0 1000 2000

[A]

f [H

f [H

gi

gi

Fourier analysis of grid current


Thank you for your attention!

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A DC-link Voltage Estimation Based Active Damping Control