Experiment of Magnetic Resonant Coupling ThreeThree ... Experiment of Magnetic Resonant ... ThreeThree----phase Wireless Power Transferphase Wireless Power Transfer ... and Load Value

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Experiment of Experiment of Experiment of Experiment of Magnetic Resonant Coupling Magnetic Resonant Coupling Magnetic Resonant Coupling Magnetic Resonant Coupling

ThreeThreeThreeThree----phase Wireless Power Transferphase Wireless Power Transferphase Wireless Power Transferphase Wireless Power Transfer

Yusuke Tanikawa, Masaki Kato, Takehiro Imura,

Yoichi Hori


2/26

What is our research?


3/26

0. What is our study? : Movie

1. Background of Wireless Power Transfer

1.1. General information of WPT

1.2. Why three phase?

2. Approach of our study

2.1. General info. & parameters

2.2. Theoretical formula

2.3. Experiment and result

3. Conclusion and future works

Contents


4/26






2.1. General info. & parameters




Contents


5/26

Wireless Power Transfer (WPT)

Applications: EV, mobile, and battery charger

Conventional WPT: Single phaseAC transfer

1.1. General info. for WPT 1/3


6/26

MethodsMagnetic

InductionMagnetic Resonant

CouplingMicrowave

Images

Transfer Gap Up to 0.2 m Up to 10 m A few hundred km

Efficiency Up to 95% Up to 97% Up to 60 %

Robustness for

Displacement Poor Great Good

6/26

Three methods of WPT technologies



7/26

• Transmitter and receiver: LC resonators

• High efficiency (around 90%) at 1 m gap

• Transfer frequency: 100 kHz to 20 MHz

– Power devices for kHz switching

• Relay resonators (single phase)

– Suitable for charging EVs while running

Magnetic Resonant Coupling



8/26

1. Advantage for high power transfer

2. Suitable characteristics for WPT

~~~~

~~~~~~~~Z

Z

Z

a a'

b'c c'

N N'

++

b

1.2. Why three phase? 1/3


9/26

Advantages for high power transfer

Single phase Three phase

Power limit ratio 1 3

Device quantity 2 (4 switches, 2 lines) 3 (6 switches, 3 lines)

Circuits

• Larger power capacity with same devices– Capacity limit: three times of single phase

(High frequency devices: Low power limit)

• Relatively simple system



10/26

Photo ：Wikipedia Photo：Toyonaka industry WEB

Suitable characteristics for WPT

Conventional method

　単相交流の整流電圧

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 60 120 180 240 300 360

位相角[°]

×Vo

整流前波形

整流波形

Single phase 図　三相交流の全波整流

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 60 120 180 240 300 360

位相角[°]

×V

o

U相 V相W相整流波形

Three phase

AC (U)

AC (W)

AC

DC

AC (V)

DC

• Smaller ripples of rectified DC

• Rotation symmetry: contact-less terminal



11/26






2.1. General information & parameters




Contents


12/26

1. Comparison of data and theoretical formula

2. Rotation experiment: collection of measured values• Each 15 degree from 0 to 360 degree

• Mutual inductance between resonators

• Ratio of voltage (V), current (I), and power (P)

Mutual inductance

(Measured value)

Ratio between transmitter and receiver

(Calculated value)Formula

Receiver V, I, and P

(Measured value)

Ratio between transmitter and receiver

(Measured value)

ComparisonTransmitterV, I, and P

(Measured value)

2.1. General info. & parameters 1/2

Experiment Experiment Experiment Experiment & & & & analysis of Threeanalysis of Threeanalysis of Threeanalysis of Three----phase WPTphase WPTphase WPTphase WPT


13/26

Coupling coefficient

(nondimensionalized mutual inductance)

Efficiency (Power ratio)

Power factor = 1.0 (resonant condition)

Current ratio

1

2

I

IAi =

iv

in

out AAIV

IV

P

P⋅=

⋅⋅

==11

22ηH

L

L

L

L

Lk mmm

µ88021

===

Voltage ratio

1

2

V

VAv =

~~~~

~~~~ ~~~~

2nd side

1st side

V2

I2

I1V1 ~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~~~~~

~~~~~~~~ ~~~~~~~~

2nd side

1st side

V2

I2

I1V1

mL

Receiver side

Transmitter side

2.1. General info. & parameters 2/2


14/26

Resonance: simple formula of mutual inductance and load resistance

At experiment; RL=50 ohm

Base theoretical formula of single phasemL LR

22110 CLCL ==ω Voltage ratio

Current ratio


),()( 2

0211

0

1

2Lmv

mL

Lmv RLA

LRRRR

RLj

V

VA =

++==

ωω

),()( 2

0

1

2Lmi

L

mi RLA

RR

Lj

I

IA =

+==

ω

)()(

)(2

02112

2

0

mLL

Lmiv

LRRRRRR

RLAA

ωω

η+++

=⋅=Masaki Kato, Takehiro Imura, Yoichi Hori, “The Characteristics when Changing Transmission Distance

and Load Value in Wireless Power Transfer via Magnetic Resonance Coupling”,

The 34th International Telecommunications Energy Conference (INTELEC 34th), 2012

2.2. Theoretical formula 1/3


15/26

• Three phase; a lot of mutual inductance values

To adapt the single phase formula;

how to combine the values into one value?

• Combination of trigonometric function

)sin()()(

)3

2sin()

3sin()sin(

~

133221

2

3

2

2

2

1

321

φω

πω

πωω

+++−++=

++++=

tLLLLLLLLL

tLtLtLL

mmmmmmmmm

mmmm

Combined Lm

Phase difference

++−++

−−=

++−++

−=

)()(

)2/()2/(cos

)()(

)2/3()2/3(sin

133221

2

3

2

2

2

1

321

133221

2

3

2

2

2

1

32

mmmmmmmmm

mmm

mmmmmmmmm

mm

LLLLLLLLL

LLL

LLLLLLLLL

LL

φ

φ

Modification of formula to three phase

~~~~

~~~~ ~~~~

2nd side

1st side

V2

I2

I1V1 ~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~~~~~

~~~~~~~~ ~~~~~~~~

2nd side

1st side

V2

I2

I1V1

mL

Receiver side

Transmitter side~~~~

~~~~ ~~~~

2nd side

1st side

V2

I2

I1V1 ~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~

~~~~ ~~~~

~~~~~~~~

~~~~~~~~ ~~~~~~~~

2nd side

1st side

V2

I2

I1V1

mL

Receiver side

Transmitter side



16/26

• Efficient formula: function of load resistance

• Optimal value of load resistance

2

0

1

22

2 )( mL LR

RRR ω+=

)()(

)(2

02112

2

0

mLL

Lmiv

LRRRRRR

RLAA

ωω

η+++

=⋅=

Optimal load for efficient maximization



17/26

• Resonant frequency: 120 kHz

• Cable: Y connection

– Rotation symmetry

– 50 ohm load resistance

• Resonators Phase a Phase b Phase c

Self inductance［μH］ 8.73×102 8.68×102 8.69×102

Internal resistance［Ω］ 1.21 1.23 1.12

Resonant capacitance［pF ］ 2.04×103 2.09×103 2.04×103

Quality factor 5.46×102 5.36×102 5.89×102

Resonant frequency［kHz］ 1.19×102 1.19×102 1.20×102

Self inductance［μH］ 8.67×102 8.69×102 8.69×102

Internal resistance［Ω］ 1.17 1.23 1.20

Resonant capacitance［pF ］ 2.07×103 2.03×103 2.04×103

Quality factor 5.63×102 5.36×102 5.49×102

Resonant frequency［kHz］ 1.19×102 1.20×102 1.20×102

Cable: 2 mm2

Diameter: 1.7 mm

Pitch of coil: 2.5 mm

Capacitor: 2000 pF

Receiver

Transm

itter

2.3. Experiment 1/7 (Setting)


18/26

A-A

B-A

C-A

0.10 0.200.000

240

120 60

180

300

0

240

120 60

180

300

[deg]

mLkH

L

L

L

L

Lk mmm

µ88021

===

Combined mutual inductance;

calculated from measured values

Mutual inductance (Coupling coefficient )

mLk

2.3. Experiment 2/7 (Result 1/6)

Close position: small rotation angle

Strong coupling


19/26

最適負荷

LR

0

240

120 60

180

300

[deg]

][Ω18060 120

最適負荷

LR

0

240

120 60

180

300

[deg]0

240

120 60

180

300

0

240

120 60

180

300

[deg]

][Ω18060 120

2

0

1

22

2 )( mL LR

RRR ω+=

Similar shape to mutual inductance

Optimal load resistance

Optimal value

LZ



20/26

A-A

B-A

C-A

A-A Cal

B-A Cal

C-A Cal

150 270300

240

120 60

180

300

[deg]

[deg]

A-A

B-A

C-A

A-A Cal

B-A Cal

C-A Cal

150 270300

240

120 60

180

300

[deg]0

240

120 60

180

300

0

240

120 60

180

300

[deg]

[deg]

0-45 degree; phase = -90 degree

60 degree; phase = 180 degree

75-120degree; phase = 150degree

=－120－90＋360 degree

++−++

−−=

++−++

−=

)()(

)2/()2/(cos

)()(

)2/3()2/3(sin

133221

2

3

2

2

2

1

321

133221

2

3

2

2

2

1

32

LLLLLLLLL

LLL

LLLLLLLLL

LA

φ

φ

Precise shape

Between calculation and

measured value

Phase difference of voltageφ2.3. Experiment 4/7 (Result 3/6)


21/26

Calculated value < Measured value

At optimal load; circular shape

At 60 degree,

Voltage ratio is maximum.

2

0211

0

)( mL

Lmv

LRRRR

RLjA

ωω

++=

Voltage ratiovA



22/26

50[Ω]負荷計算値50[Ω]負荷実測値最適負荷計算値

2.0 3.01.0

iA

)( 2

0

RR

LjA

L

mi +=

ω

Calculated value > Measured value

At optimal load; circular shape

At 60 degree,

Current ratio is minimum.

Current ratioiA



23/26


0.4 1.00 0.6 0.80.2η

0

240

120 60

180

300

[deg]


0.4 1.00 0.6 0.80.2η

0

240

120 60

180

300

[deg]0

240

120 60

180

300

0

240

120 60

180

300

[deg] 0-45 degree： 80%

60 degree：35%75-120 degree：80%

Maximum deference of

calculated and measured value;

at 60 degree




24/26






2.1. General information & parameters




Contents


25/26

3. Conclusion & future works

• Experiment and analysis of Three-phase WPT

– 1. Comparison of data and theoretical formula

Each formula draws the similar calculated value as measured value

– 2. Rotation experiment

Rotation symmetry of transmitters are shown in experimental result

• Future works

– High power experiment and analysis

– Coupling analysis as cross coupling.


Thank you for listening26/26

Advanced experiments are undergoing…


Appendix


Current

Voltage

Power

DC-DC Efficiency

Device efficiency

%83830.0884.0

737.0===η

WPT efficiency

Receiver voltage

Transmitter voltage


回路構成

50Hz

Inv.v Load

(Leaf)

DC電源可変電圧

定電流モード有り

高周波インバータ共振器整流器負荷

50Hzインバータ＋Leaf または20Ω琺瑯抵抗



)3

2sin()

3sin()sin(

)sin()2

3

2

3()

22(

)cos()2

3

2

3()sin()

22(

3

2sin)cos(

3

2cos)sin(

3

sin)cos(3

cos)sin(

)sin(

)3

2sin()

3sin()sin(

321

2

32

2321

3232

1

3

2

1

321

πω

πωω

φω

ωω

πω

πω

πω

πω

ω

πω

πωω

++++

+−+−−=

−+−−=

++

++

=

++++

tAtAtA

tAAAA

A

tAAtAA

A

ttA

ttA

tA

tAtAtA


線間電圧と相電圧

対称Y形起電力において

ea====Em1sin(ωωωω t−−−− 0°)++++Em3sin3ωωωωt++++Em5sin(5ωωωωt−−−− 0°)++++ •••

eb====Em1sin(ωωωω t−−−−120°)++++Em3sin3ωωωω t++++Em5sin(5ωωωω t−−−−240°)++++ •••

ec====Em1sin(ωωωω t−−−−240°)++++Em3sin3ωωωω t++++Em5sin(5ωωωω t−−−−120°)++++ •••

~~~~ ea

eb

ec~~~~~~~~

a

bc

N

+

++

eab

ebc

eca

各線間電圧は eab====ea−−−−eb====Em1sinωωωωt−−−−sin(ωωωω t−−−−120°)++++Em5sin5ωωωωt−−−−sin(5ωωωωt−−−−240°)++++ •••

線間電圧に三倍次高調波はあらわれない


Y形結線における高調波

ea

eb

ec

ea eb ecea

eb

ec

第1次調波など (正相) 第3次調波など (同相) 第5次調波など (逆相)

ea++++eb++++ec====0 ea++++eb++++ec====3Em3sin3ωωωω t ea++++eb++++ec====0

~~~~ ea

eb

ec~~~~~~~~

Z

Z

Z

a a'

b b'c c'

N N'

+

++

~~~~ ea

eb

ec~~~~~~~~

Z

Z

Z

a a'

b b'c c'

N N'

+

++

ia

ib

ic

iN ==== ia++++ ib++++ ic平衡回路でも、同相の高調波があれば中性点間に電流が流れる


Delta connection with harmonic waves

第1次調波など (正相) 第3次調波など (同相) 第5次調波など (逆相)

ea++++eb++++ec====0 ea++++eb++++ec====3Em3sin3ωωωωt ea++++eb++++ec====0

平衡回路でも同相の高調波があれば起電力回路に循環電流が流れる

igigig

ig====ea++++eb++++ecZag++++Zbg++++Zcg

ig====ea++++eb++++ecZag++++Zbg++++Zcg~~~~~~~~

eab

ebc

eca~~~~~~~~

~~~~~~~~Zbc

Zca Zab

a a'

b b'c c'

+

+

+

Zal

Zbl

Zcl

Zbg

Zag

Zcg


0 phase current

ea====e(t)====Em1sinωωωω t++++Em3sin3ωωωω t ++++Em5sin5ωωωω t++++ •••

eb====e(t−−−−T/3)====Em1sinωωωω(t−−−−T/3)++++Em3sin3ωωωω(t−−−−T/3)++++Em5sin5ωωωω(t−−−−T/3)++++ •••

====Em1sin(ωωωω t−−−−120°)++++Em3sin(3ωωωω t )++++Em5sin(5ωωωω t−−−−240°)++++ •••

ec====e(t−−−−2T/3)====Em1sin(ωωωω t−−−−240°)++++Em3sin(3ωωωω t )++++Em5sin(5ωωωω t−−−−120°)++++ •••


Previous research

• induction


Analysis for previous research

• Induction without magnetic resonant coupling

Ladder coil transmitter for rail transport

– Small air gap

– Three phase receivers are original of us

–

Documents

Experiment of Magnetic Resonant Coupling ThreeThree ... Experiment of Magnetic Resonant ... ThreeThree----phase Wireless Power Transferphase Wireless Power Transfer ... and Load Value