2014 ANSYS Electronics Simulation Expo
Maxwell-3D analysis of small capacity contactless power
transfer system applied AGV
Presenter Kiyotaka Fuji*, **
(Fellow Energy Co.,Ltd. / Kyushu Institute of Technology Adjunct professor)
Prof. Masayuki Hikita***, Asso. Prof. Masahiro Kozako***, MS. Akihiro Imakiire***
, MS. Akinari Yamane***, MS. St. Takahiro Kojima*** ( Kyushu Institute of Technology)
, Yutaka Imoto****, Keiichi Honda**** (HEADS Co.,Ltd)
Abstract - This paper deals with the basic analysis characteristics of a small capacity Contactless Power Transfer System
(CPTS) applied AGV (Automated Guided Vehicle) using Maxwell-3D analysis and Simplorer circuit analysis, and the
experimental results. This research shows the examination result of power efficiency gap dependence and power supply
efficiency and Loss about A-coil and B-coil using small capacity CPTS. Latest, as a result, it is shown the compensation
simulation with examination at the coil winding shape difference about the electromagnetic field analysis characterization.
Keywords：contactless power transfer system, electromagnetic analysis, Maxwell-3D, AGV
1.
secondary coil, the center tap method of two diodes
rectifier and LC filter is applied.
Introduction
Recently, the non-contact power supply of electric
automobiles and mobile device applications using the
magnetic field resonance system and an electromagnetic
induction method is performed. This has begun to be
practical application in electrical equipment of small
capacity. As an example, there is an application to small
power feed device to the AGV (Automated Guided
Vehicle) of automobile production factories. In this
presentation, Analysis of the power supply efficiency
characteristics for contactless power transfer system of the
electromagnetic induction system of the small-capacity
electrical equipment will be introduced. Furthermore,
using the ANSYS Maxwell-3D electromagnetic analysis
support tool and Simporer circuit analysis tool, the power
supply efficiency gap analysis of small capacity contactless
power transfer device is introduced.
2.
VDC
Inverter
**
***
****
Vin
L1
Iout
L2
Vout Load
Lr
Gap
Fig. 1. small capacity Contactless Power Transfer System model.
3.
Power Supply A-coil model
In Figure 2, is shown the A-coil reference model of small
capacity Contactless Power Transfer System (CPTS). In
Table 1, is shown the Inductance, dimensions, number of
turns of each coil. This coil is an air-core coil. Resonance
coil and the primary coil were confirmed characteristics
using the same specification. This coil is an air-core coil.
Resonance coil and the primary coil were confirmed
characteristics using the same coil specification (Each
inductance is measured with an LCR meter [HIOKI
3532-50]).
Small capacity CPTS circuit model
In Figure 1, is shown the reference circuit model of small
capacity Contactless Power Transfer System (CPTS). This
is composed of a resonant circuit, VDC of DC power
supply, an inverter, a primary coil L1, the secondary coil
L2, the primary coil L1. Resonant circuit is constructed in
the resonant capacitor Cr and resonant coil Lr. And, in L2
*
Cr
Iin
100mm
Fellow Energy Co.,Ltd. C.E.O.
2-6-7-306 Adachi, Kokurakita-ku, Kitakyushu, 802-0042,Japan.
rm306@p-adachi.gr.jp, fuji19690708@gmail.com
45mm
(a) Primary coil L1
100mm
45mm
(b) Resonance coil Lr
Secondary coil & Resonance coil
Kyushu Institute of Technology Adjunct professor (Endowed Chair)
1-1 Sensui-cho, Tobata-ku, Kitakyushu, 804-8550, Japan.
Kyushu Institute of Technology, Department of Electrical Engineering
1-1 Sensui-cho, Tobata-ku, Kitakyushu, 804-8550, Japan.
75mm
45mm
Gap
HEADS Co., Ltd.
1-34 Shinhama-cho Kandamachi, Miyako-gun, Fukuoka 800-0321,
Japan. http://www.headscorp.co.jp
Primary coil
(c) Secondary coil L2
(d) Arrangement of coils
Fig. 2. Photographs of each coil.
2014 ANSYS Electronics Simulation Expo ©FE-Fuji
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Table. 1.
Resonance coil
Secondary coil
150
L1
Lr
L2
138
45
100
40
132
45
100
40
8.5
45
75
10
100
1
Vin [V]
50
0
0
-50
-1
-100
4.
Power efficiency gap dependence of A-coil
4
Vin [V]
2
0
Fig. 3.
Iout
Vout [V]
Efficiency η [%]
30
20
10
10
20
30
40
50
60
70
80
90 100 110
Power [W]
Fig. 5. Measurement result of transmission efficiency.
50
45
40
35
30
25
20
15
10
5
0
Input power Pin
Output power Pout
0
10
20
30
40
50
60
70
80
90 100 110
Gap g [mm]
Fig. 6. Measurement result of input and output power.
5.
Power efficiency gap dependence of B-coil
In Figures 7 and 8, are shown the reference circuit and
Appearance of B-coil model. Resonant and the secondary
coil is constructed for storing within the enclosure as the
power receiving coil. The power supply side coil and the
power receiving coil were placed directly opposite. The
gap length g was changed from 10 to 50 millimeters. Using
digtal power meter (YOKOGAWA, WT1600), the power
supply efficiency η of between the coils was derived by
measuring the input power Pin and output power Pout of
coils.
Inverter
Coil
Rectifier
Cr
5
3
40
Gap g [mm]
(5µs/div)
4
6
(5µs/div)
50
0
6
Vout
0
3φ 200 V
Iout [A]
Vout [V]
8
1
Vout
0
(a) Input
10
2
Iout
60
-2
Time [s]
Iout [A]
-150
3
4
70
-1
Vin
4
6
(b) Output
Fig. 4. Measurement waveforms at g = 50 mm.
Iin [A]
-50
-100
5
Time [s]
1
0
6
8
0
Iin
0
(5µs/div)
10
2
2
50
-2
Time [s]
(a) Input
Table. 2. Experimental conditions.
DC voltage, VDC
24 V
Inverter frequency, f
50 kHz
Resonance capacitor, Cr
80 nF
Gap, g
0~100 mm
Load
Light bulb
100
Vin
-150
In the reference circuit of Figure 1, CPTS power supply
efficiency of the gap length change between the coils was
measured. Efficiency was derived by measuring the output
current Iout and output voltage Vout of load side, and input
current Iin and Input voltage Vin of the primary coil side.
In efficiency measurement used the digital power meter
(YOKOGAWA: WT1600). And, in Table 2 shows the
experimental conditions. Load was used the rated 72W
bulb (36Wx2, two-parallel). At this time, the gap length g
is varied from 0 to 100 millimeters. In Figures 3 and 4,
shows the each input and output waveforms of the gap
length from 0 to 50 millimeters. When the gap length is at
g=0 mm, in the phase difference between the input current
and input voltage, there is almost no difference, and the
output voltage, output current was 6.8V, 3.5A. When the
gap length is at g=50[mm], the phase difference between
the input current and input voltage was about 90 degree,
and the output voltage, output current was 0.2V, 1.3A. In
Figure 5 is the measurement result of the input power
supply and efficiency, Figure 6 is the measurement result
of the output power and Power supply efficiency. By
Figures 5 and 6, the more the gap length g, the more input
and output power and Power supply efficiency is reduced.
Form these results, at g=5 mm, the maximum efficiency is
61%, the transmission power is 28.3W. At g=50 mm, the
power supply efficiency is 6.7%, the transmission power is
0.32W. In at least 20 mm, efficiency is reduced by leakage
flux increased gap length. This is because the resonance
frequency is changed by the inductance value decreases in
the gap length increases.
150
2
Iin
Iin [A]
Inductance [µH]
Inner diameter [mm]
Outer diameter [mm]
Number of turns
Specifications of each coil.
Primary coil
L2
L1
2
RL
Lr
Gap
1
η
0
Time [s] (5µs/div)
(b) Output
Measurement waveforms at g = 0 mm.
Pin
Pout
Fig.7. small capacity Contactless Power Transfer System of B coil.
2014 ANSYS Electronics Simulation Expo ©FE-Fuji
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Inverter
Table.3. B-coil test condition
Coil
Rectifier
Iout
Cr=1.3µF
3φ 200 V
L2= 8.5 µH
L1=105µH
Lr=33µH
Vout
RL=0.51 Ω
Gap
(g = 10 mm)
f = 25 kHz
Fig.10. Contactless Power Transfer System efficiency model of B-coil
In Figure 11, shows the measurement waveform of
output voltage Vout and output current Iout at the gap
length g=10 mm. Output voltage and current have a
pulsation both, however, it can be transmitted to the load
about 1 kW electric power (27.4V average output voltage,
35.5A average output current). In Figure 12, shows the
measurement results of Loss at the Inveter, the Coils, the
Rectifire constituting the contactless power transfer system
equipment of about 1 kW output. In the each parts Loss of
contactless power transfer system equipment, Inveter Loss
was 161W, Coils Loss was 63W, Rectifier Loss was
106W, Total Loss was 330W (Total Loss = Inverter Loss +
Coils Loss + Rectifier Loss). For loss rate of each part for
entire device loss, Inverter Loss was 48.8%, Coils was
19.0%, Diode Rectifire Loss was 32.2%. In this results,
contactless power transfer system equipment Loss 80% of
B-coil type have occured at the Inverter and Rectifire.
Especially, the greater the inverter loss rate were analyzed.
Therefore, in order to reduce the loss of contactless power
transfer system equipment prototype, reducing the rectifier
and the inverter loss is important.
Fig.8. B-Coil Appearance
120
40
100
100
90
80
70
60
50
40
30
20
10
0
Iout
80
60
Vout [V]
94.5 %
88.0 %
30
40
20
Iout [A]
Efficiency η [%]
In Figure 9 shows the efficiency measurement result η of
between the coils. The coils power supply efficiencyηis
confirmed that at the gap length g=10 mm was 95%, at
g=50 mm was 88%, at the gap length changing from 10 to
50 millimeters was around 95% coil efficiency. For the
location shift which the power receiving side coil and the
power supply side coil are not arranged directly opposite,
we will continue to implement characterization in the
future.
20
0
10
Vout
-20
-40
0
Time [10us/div]
0
10
20
30
40
50
Fig.11. Output waveform
60
Gap g [mm]
Fig.9. Efficiency measurement result η of between the coils
350
330W（100%）
300
6.
B-coil power supply efficiency and Loss
250
Loss [W]
In Figure 10 shows the configuration example of B-coil
type circuit for Loss analysis. In order to analyze the loss
characteristics, the gap length between the power supply
side coil (primary coil L1) and the power receiving side
coil (secondary coil L2 and LR resonant coil) was fixed
g=10 mm. The primary side of the non-contact power
feeding coil, applied from the inverter 25 kHz square wave
voltage to the primary coil. The secondary side was
measured by connecting a load resistive R L (The Loss of
Inverter, the coils, the rectifier is derived using WT1600,
YOKOGAWA).
200
161W（48.8%）
150
106W（32.2%）
100
63W（19.0%）
50
0
Inverter
Coil
Rectifier
Total
Fig.12. Loss in contactless power transfer system
2014 ANSYS Electronics Simulation Expo ©FE-Fuji
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7.
ANSYS analysis reference of CPTS coil
In Figure 13 introduces the characterization of the
electromagnetic field analysis by the coil winding shape
difference used ANSYS electromagnetic field analysis
support tool (ANSYS Maxwell 2D/ Maxwell 3D). Here,
the magnetic field analysis results by the coil winding
shape difference is shown.
Fig.15. B-coil Electromagnetic Field Analysis using Maxwell-3D
Fig.13a. XY axis Coil Analysis using ANSYS Maxwell-3D
Fig.16. Inductance Analysis using ANSYS Maxwell-3D
In Figure 16 shows the Inductance Analysis result using
ANSYS Maxwell-3D. Dots data shows the measurement
data of the small capacity CPTS madel. Line data is the
Maxwell-3D Simulation data. There data were able to be
the same specification result. This simulation mathod can
be applied for this CPTS analysis.
8.
Conclusion
Examination of gap dependency of the power supply
efficiency of small-capacity Contactless Power Transfer
System equipment have been performed. In this Research,
showed that the power efficiency gap length is the
maximum efficiency with respect to the vertical direction
can be confirmed. In the future, simulation analysis using
ANSYS Maxwell-3D and experimental evaluation of the
Contactless Power Transfer System (CPTS) equipment of
high-efficiency power transmission with respect to the
horizontal direction gap will be performed. This research
achievements is the cooperative outcome by endowed chair
Mr. Fuji and Professor Hikita laboratory of Kyushu
Institute of Technology. In addition, we appreciate the
research cooperation received from HEADS Co.,Ltd..
Fig.13b. XZ axis Coil Analysis using ANSYS Maxwel-3D
Fig.13c. XZ axis Coil Analysis using ANSYS Maxwell 2D
Reference
In Figure 13 shows the electromagnetic field analysis
about with or without coil wiring line to line space at Flat
winding and Vertically winding. In the contactless power
transfer system, applying a coil shape of the best electro
magnetic intensity distribution is important. Therefore, by
performing the confirmation of magnetic field distribution
using ANSYS analysis tool is recommended. In Figures 14
and 15 show the Electromagnetic Field structure Model
and its analysis using Maxwell-3D about the B-coil CPTS
without the Frite Core of magnetic material.
[1] A Yamane, K Koyanagi, A Imakiire, K Fuji, M Kozako, M
Hikita, Y Imoto, K Honda, “Gap Dependence of
Transmission Efficiency in Contactless Power Transfer
System with Small Capacity”, 2013 IEE-Japan Industry
Applications Society Conference (JIASC2013), Yamaguchi,
Japan, No.1-99, p.I399-I400, 2013
[2] T Kojima, A Yamane, A Imakiire, K Fuji, M Kozako, M
Hikita, Y Imoto, K Honda, “A Coil Power Supply Efficacy
Study in 1kW class Contactless Power Transfer System”,
2013 Committee Conference of Electrical and Electronics
Engineerings in Kyushu IEE Japan, Kumamoto, Japan,
No.04-2P-06, 2013
[3] A Yamane, T Kojima, A Imakiire, K Fuji, M Kozako, M
Hikita, Y Imoto, K Honda, “A Loss Study in 1kW class
Contactless Power Transfer System”, 2013 Committee
Conference of Electrical and Electronics Engineerings in
Kyushu IEE Japan, Kumamoto, Japan, No.04-2P-07, 2013
Fig.14. Electromagnetic Field Analysis Model using Maxwell-3D
2014 ANSYS Electronics Simulation Expo ©FE-Fuji
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