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Study on IPT Charging Systems With Hybrid Topology for Configurable Charge Currents

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Based on the double LCL topology circuit, a multiple-electric-bicycle charging method with a single inverter is proposed to meet various charging requirements by adding two switches and an additional capacitor in the secondary circuit, so that a single charging stand can charge various charging-profile bicycles. Constant current or constant voltage output can be realized by switching the switches to change the topology of resonant tanks. Furthermore, this method has the following advantages: no communication link between primary and secondary circuits needed, low complicated control circuit and system complexity, nearly no reactive power required. In order to verify the effectiveness and feasibility of the method, this paper sets up two experimental prototypes with charge voltages 48V and charge currents 2A/4A, respectively. The experimental results show that the method can meet the above requirements and improve the utilization rate of the charging stands.
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38 11 Vol.38 No.11 Jun. 5, 2018
2018 65 Proceedings of the CSEE ©2018 Chin.Soc.for Elec.Eng. 3335
DOI10.13334/j.0258-8013.pcsee.170469 文章编号:0258-8013 (2018) 11-3335-09 中图分类号:TM 46
可配置充电电流的变结构无线充电系统研究
麦瑞坤 1,张友源 1,陈阳 1,寇志豪 1,何正友 1,李伟华 2
(1.西南交通大学电气工程学院,四川省 成都市 610031
2.暨南大学电气信息学院,广东省 珠海市 519070)
Study on IPT Charging Systems With Hybrid Topology for Configurable Charge Currents
MAI Ruikun1, ZHANG Youyuan1, CHEN Yang1, KOU Zhihao1, HE Zhengyou1, LI Weihua2
(1. School of the Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan Province, China;
2. College of Electrical and information, Jinan University, Zhuhai 519070, Guangdong Province, China)
ABSTRACT: Based on the double LCL topology circuit, a
multiple-electric-bicycle charging method with a single inverter
is proposed to meet various charging requirements by adding
two switches and an additional capacitor in the secondary
circuit, so that a single charging stand can charge various
charging-profile bicycles. Constant current or constant voltage
output can be realized by switching the switches to change the
topology of resonant tanks. Furthermore, this method has the
following advantages: no communication link between primary
and secondary circuits needed, low complicated control circuit
and system complexity, nearly no reactive power required. In
order to verify the effectiveness and feasibility of the method,
this paper sets up two experimental prototypes with charge
voltages 48V and charge currents 2A/4A, respectively. The
experimental results show that the method can meet the above
requirements and improve the utilization rate of the charging
stands.
KEY WORDS: inductive power transfer (IPT); LCL topology;
constant current; constant voltage; sharing charging stand
摘要:该文基于双 LCL 拓扑电路提出了在副边电路增加两
个开关和一个附加电容的方法,实现单个逆变器对多个电动
自行车充电,且不同充电电流的电动自行车可以共享充电
桩,提高充电桩的使用率。通过切换开关和附加电容可改变
谐振电路拓扑,实现恒流或恒压输出的相互转换。此外,
方法还具有以下明显优点:无需原副边通信和复杂的控制电
路,系统复杂性低,几乎没有无功输入。为了验证该方法的
基金项目:国家重点研发计划轨道交通专项课题(2017YFB1201002)
四川省青年科技基金项目(2016JQ0033);国家杰出青年科学基金项目
(51525702);珠海轨道交通健康运营协同创新中心(55560307)
The National Key R&D Program of China (2017YFB1201002);
Sichuan Youth Science & technology Foundation (2016JQ0033); The
National Science Fund for Distinguished Young Scholars (51525702); Rail
Transit Healthy Operation Cooperative Innovation Center of Zhuhai
(55560307).
有效性和可行性,该文搭建了充电电压 48V充电电流分别
2A 4A 的实验原理样机,实验结果表明该方法满足上
述要求且能够提高充电桩的使用率。
关键词:感应电能传输;LCL 拓扑;恒流充电;恒压充电;
共享充电桩
0 引言
感应电能传输(inductive power transferIPT)
术是一种利用磁场等软介质实现非接触电能传输
的新型供电技术[1-2]其以供电灵活、安全、稳定性
高及环境亲和力强等优点广泛运用于医疗、消费电
子产品、水下供电、电动车充电和轨道交通等领
[3-8]避免了传统插拔系统存在的接触火花和插头
老化等弊端。电动自行车具有无污染、低价和安全
等优点[8],日渐成为人们的重要代步工具。传统的
充电方式存在触电、漏电、电火花等安全隐患,
IPT 技术应用于电动自行车充电,解决了上述问题,
也成为近年来研究热点[9]
1所示为典型的电池充电曲线[10]电池充电
过程可分为两个阶段:恒流充电和恒压充电。整个
充电过程电池等效电阻 RB可能逐渐从几增加到
几百[11]为了实现对电池安全稳定充电,感应式
无线充电系统需要提供恒定的电流和电压。
目前有很多方法可以实现 IPT 系统恒流或恒压
输出,大致可分为 1)采用控制的方式和 2)采用
电路拓扑的方式。采用控制的方式:IPT 系统原
边逆变器之前加入前级变换器[12]通过控制变换器
来输出恒定电流或电压;通过逆变器的变频控
[13-14]和定频变占空比控制[15]也能输出恒定电流
或电压。这几种实现方式增加了控制复杂性且需要
3336 38
充电时间
电池电流
IB
CC
CV
电池
电流/A
电池电压
VB
电池等效电阻
RB
电池
电压/V
1 典型铅蓄电池充电曲线
Fig. 1 Typical charging profile of a lead-acid battery
原副边之间通信。此外,在副边电路输出端增加后
级变换器[16]也能实现系统恒流或恒压输出。采用电
路拓扑方式:基于 SS 电路拓扑,在原边电路加入
一个附加电容和一个半导体开关[9] ,或者采用
S-LCL 电路拓扑,在副边电路加入一个附加电容和
一个半导体开关[17]通过半导体开关的切换来输出
恒定充电电流和电压,但这两种方法中系统存在较
大无功,逆变器开关损耗大。为了解决该问题,
[18]通过半导体开关动作实现 SS PS 拓扑电路
或者 SP PP 拓扑电路切换,实现恒流恒压输出;
也有学者基于 S-LCL 拓扑电路,提出在副边电路加
入一个附加电容和两个半导体开关[10]的方法,实现
对电池充电。以上采用电路拓扑的方法均可用于电
动自行车充电,但是在共享充电桩的前提下,无法
通过配置参数改变系统充电电流,难以用于不同规
(充电电流不同)的电动自行车。
为了实现单个逆变器对多个电动自行车充电、
不同充电电流的电动自行车可以共享充电桩且系
统几乎没有无功输入,本文首先分析 LCL 拓扑电路
SS 补偿拓扑得出二者的电路传输特性;然后在
其基础上给出双 LCL 拓扑电路,并提出在副边电路
加入两个开关和一个附加电容的方法实现恒流
压充电;最后,本文搭建了充电电压 48V,充电电
流分别为 2A 4A 的实验原理样机,验证该方法
的有效性和可行性。
1 系统拓扑电路的推导分析
1.1 LCL 拓扑电路分析
2(a)所示为 LCL 拓扑结构的电路, P1
U
为高
频电压源,R1为负载电阻。根据诺顿等效定理,
2(a)所示电路等效成图 2(b)所示的电路,当 LP1
CP1 满足关系:
2
P1 P1 1LC
(1)
LP1 CP1 并联谐振时,其并联所组成的支
LP1
Z1
P1
U
CP1
LP2 R1
I
R1
U
R1LP1 CP1
LP2 R1
I
R1
U
R1
P1
P1
j
U
L
(a) 原电路 (b)
等效电路
2 LCL拓扑电路图
Fig. 2 Diagram of LCL topology circuit
(2(a)中的虚框)相当于开路,流经负载的电流
等于等效电流源的电流,即:
P1
1P1P1
P1
j
j
R
U
I
CU
L


(2)
由此可知,当系统角频率
高频电压源 P1
U
CP1 不变,并且 LP1 CP1 发生并联谐振时,负载电
R1
I
保持不变,可看作恒流源。结合式(1)可计算
得到输入阻抗 Z1
12
P1 P1 1 P1 P2
1
[j( 1)]
ZCCR CL
 

(3)
由式(3)容易得到,当满足:
2
P1 P2 1CL
(4)
系统输入阻抗 Z1呈纯阻性:
122
P1 1
1
ZCR
(5)
1.2 SS 拓扑电路分析
3(a)所示为SS 拓扑的IPT 系统电路。其中 P2
I
为高频电流源,R2为负载电阻,电容 CPCS与原
边自感 LP和副边自感 LS满足关系式:
2
PP
2
SS
1
1
CL
CL
(6)
将图 3(a)所示 IPT 系统电路作 T型等效,如
3(b)所示,L'
PL'
S分别为原边线圈漏感和副边线
M
M
LPR2
U
CP
P2
I
R2
LS
R2
I
CS
Z2
CPCS
L'
PL'
S
R2
U
R2
R2
I
P2
I
(a) IPT 系统 (b)
T型等效
M
M
CPK CSK
R2
U
P2
I
R2
R2
I
P2
j
M
I
CSK
R2
U
R2
R2
I
(c) 等效电路 1 (d) 等效电路 2
3 基于 SS 拓扑的 IPT 系统
Fig. 3 SS topology of IPT system
11 麦瑞坤等:可配置充电电流的变结构无线充电系统研究 3337
圈漏感,M为原副边线圈间的互感,之间的关系为
PP
SS
LML
LML


(7)
再将 CPL'
P串联等效成电容 CPKCSL'
S
串联等效成 CSK,如图 3(c)所示,然后根据诺顿等
效定理将其等效成图 3(d)所示的电路,当互感 M
电容 CSK 满足下列关系:
S
SK S
S
S
11
jjj
jj
1j0
j
MML
CC
L
C



 (8)
互感 MCSK 处于串联谐振状态,于是负载电
压等于等效电压源的电压,即:
R2 P2
jUMI

(9)
由此得出,在高频电流源 P2
I
作为输入的 SS
IPT 系统中:当系统角频率和互感 M不变时,
系统输出恒定电压。
此外,可以计算出系统输入阻抗 Z2
22
2
ZR
(10)
1.3 充电电流可配置的电路拓扑分析
1.1 节和 1.2 节分析了高频电压源 P1
U
作为输入
LCL 拓扑结构和高频电流源 P2
I
作为输入的 SS
拓扑结构的 IPT 系统电路,本节将在其基础上给出
LCL 拓扑电路。
将图 2(a)所示 LCL 拓扑电路的负载电流 1
R
I
为图 3(a)所示 SS 拓扑 IPT 系统电路的激励源,以
组合成如图 4(a)所示的电路,其中 R是负载电阻,
P
U
是高频电压源。
在图 4(a)所示电路中,当 LP1 CP1 满足式(1)
M
LP1
P
U
CP1
LP2 R1
I
R
U
R
R
I
CPCS
2
U
LPLS
(a) 恒压拓扑电路
(b) 恒流拓扑电路
M
LP1
P
U
CP1
LP2 R1
I
CPCS
LPLS
R
U
R
R
I
R2
U
CS1
LS1 LS2
4 LCL 拓扑电路
Fig. 4 Double LCL topology circuit
时,由 1.1 节的分析推导可以得知电流 1
R
I
1P1P
j
R
I
CU


(11)
CPCSMLPLS满足式(6)(7)时,由
1.2 节的分析推导并结合式(11)可以得到负载电压
R
U
2
RP1P
UMCU

(12)
由此可以得出,在系统角频率
、输入高频电
压源 P
U
互感 M和电容 CP1 不变的条件下,4(a)
所示的电路能够获得恒定的负载电压 R
U
,并通过
互感M和电容 CP1 可以调节系统输出负载电压 R
U
而电动自行车放置拾取机构后互感 M固定(假设充
电桩和电动自行车均采用统一规格的发射和拾取
机构,即原边线圈与副边线圈之间的互感 M相同)
仍可以通过 CP1 来调节系统负载电压 UR的大小。
为电容CP1 的阻抗与互感 M的阻抗的模值
之比,即:
P1
2
MP1
1
||
C
Z
Z
M
C
 (13)
则负载电压 R
U
可以表示为: RP
/UU
 。若
将系统电压增益 GV定义为负载电压与输入电压模
值之比,则系统电压增益 GV可以表示为
2
R
VP1
P
|| 1
||
U
GMC
U

(14)
此外,通过式(5)(10)可以计算出系统恒压输
出时的输入阻抗 ZV
V22 4
P1
R
ZMC
(15)
由此得出,恒压输出时,系统输入阻抗为纯阻
性,没有无功输入。
再考虑图 4(b)所示电路,LS1 CS1 间的关系
满足下式时:
2
S1 S1 1LC
(16)
1.1 节的分析推导并结合式(12)可以得到负
载电流 R
I
3
RP1S1P
j
I
MC C U


(17)
由此可以得出,在系统角频率
、输入高频电
压源 P
U
、互感 M、电容 CP1 CS1 不变的条件下,
4(b)所示的电路能够获得恒定的负载电流 R
I
通过互感 MCP1 CS1 可以调节系统输出负载电
3338 38
R
I
而当充电桩安装后,系统原边电路固定,
电桩充电电压将固定,即互感 M和电容 CP1 固定不
变,用户仍可以通过电动自行车上接收端的 CS1
节系统负载电流 R
I
的大小,即不同充电电流的电动
自行车能够共享充电桩。
为电容 CS1 的阻抗与互感 M的阻抗的模值
之比,即:
S1
2
MS1
1
||
C
Z
Z
M
C
 (18)
则负载电流 R
I
可以表示为:RP
/(j )IU M


若将系统电流增益 GI定义为负载电流与输入电压
模值之比,则系统电流增益 GI可以表示为
3
R
IP1S1
P
|| 1
||
I
GMCC
UM

 
(19)
此外,通过式(5)和式(10)可以计算出,系统恒
流输出时的输入阻抗 ZI
I6222
P1 S1
1
Z
M
CCR
(20)
由此得出,恒流输出时,系统输入阻抗为纯阻
性,没有无功输入。
2 恒流恒压模式切换分析
从图 4(b)所示的恒流输出结构切换到图 4(a)
示的恒压输出结构,需要断开 CS1 支路和补偿电感
LS1LS2本文采用的方法是串联开关 S1以断开 CS1
支路;在电感 LS2 两端并联电容 CSa,以补偿电感
LS1 LS2,从而使得系统充电模式由恒流模式切换
成恒压模式。其中电容 CSa
S2
Sa
SS1
SS2
Sa
1
jj
1
jj 0
1
jjj
LC
LL
CLC

 
(21)
为了进一步简化电路,LP2 CP串联等效为
一个电抗元件 LPe CPeLS1 CS串联等效为一个
电抗元件 LSe CSe为了简化分析,假设其分别串
联等效成 CPe CSe最后得到充电电流可配置的变
结构无线充电系统的电路,如图 5所示。
在图 5中,当开关 S1闭合,开关 S2断开时,
系统电路与图 4(b)所示的电路等效,则系统工作于
恒流模式;而当开关 S1断开,开关 S2闭合时,CS1
支路被切断,电容 CSe 串联等效前的电感 LS1 LS2
被电容 CSa 补偿,系统电路与图 4(a)所示的电路等
Q1Q3
Q2Q4
E
D1D3
D2D4
Cf
iR
VB
IB
uR
uP
iP
电池
LP1
M
S1
L
CP1 LPLS
CPe CSe
CS1
LS2
S2
CSa
5 感应式无线充电系统电路图
Fig. 5 Diagram of IPT charging system outputting
configurable charge current
效,则系统工作于恒压模式。因此,通过开关 S1
和开关 S2可以实现恒流模式与恒压模式切换。
在分析图 4中的电路时,逆变器采用高频交流
电压源 P
U
替代,高频电压源基波有效值 UP和逆变
器输入直流电压 E的关系[19]可表示为
P
22
UE (22)
5次级电路中全桥整流输入电压 UR、电流
IR和整流输出后的充电电压 VB、充电电流 IB的关
[16]可表示为
RB
RB
22
2
4
UV
I
I
(23)
式中:UR表示输入电压 uR的基波有效值;IR表示
输入电流 iR的基波有效值。
此外,由式(12)(17)(22)可知,当系统参数
确定时,系统输出电压和电流只与逆变器输入直流
电压 E有关,所以基于本文提出的方法,多个充电
系统可如图 6所示并联在同一个逆变器上[10],实 现
单个逆变器对多个电动自行车充电。
LS1k
LPek
CSek
CSak
Mk
LPkLSk
CP1k
LP1k
S2k
CS1k
S1k
Q1k Q3k
Q2k Q4k
E
D1kD3k
D2kD4k
Cfk
IBk
+
VBk
Sk
#k
Vi
Iik
Iok
Vok
Lk
LS1n
LPen
CSen
CSan
Mn
LPnLSn
CP1n
LP1n
S2n
CS1n
S1n
D1nD3n
D2nD4n
Cfn
IBn
+
VBn
Sn
#n
Iin
Ion
Von
Ln
LS11
LPe1
CSe1 CSa1
M1
LP1 LS1
CP11
LP11
S21
CS11
S11
D11 D31
D21D41
Cf1
IB1
+
VB1
S1
#1
Ii1
Io1
Vo1
L1
6 单逆变器对多系统充电的系统电路图
Fig. 6 Diagram of single inverter charge for
multiple system
11 麦瑞坤等:可配置充电电流的变结构无线充电系统研究 3339
3 感应式无线充电系统电路参数设计
设感应式无线充电系统的恒流充电电流为 IB
恒压充电电压为 VB逆变器输入直流电压为 E,系
统工作角频率为
,原边线圈的自感为 LP副边线
圈的自感为 LS原边线圈与副边线圈间的互感为 M
将式(22)(23)代入式(14),得到初级补偿电
CP1
B
P1 2
V
C
M
E
(24)
将式(22)(23)和式(24)代入(19),得到次级
补偿电容 CS1
2
B
S1
B
8
I
CV
(25)
将式(24)代入式(1),得到电感 LP1
P1
B
EM
LV
(26)
为了减小系统输入的无功功率,以降低逆变器
的容量要求,应使得系统输入阻抗呈纯阻性,将
(24)代入式(4),得到电感 LP2 需满足:
P2
B
EM
LV
(27)
将式(25)代入式(16),得到电感 LS1
B
S1 2
B
8V
L
I
(28)
同理,为了使得系统输入阻抗呈纯阻性,电感
LS2 也应该满足
2LS2CS11(对比于式(4)),进而得
到电感 LS2
B
S2 2
B
8V
L
I
(29)
通过式(6)可以计算出 CPCS分别为
P2
P
S2
S
1
1
CL
CL
(30)
LP1 CP串联等效为原边电抗器 ZP其值由
下式决定:
BP
PP2
PB
1
jj
j
EM V L
ZL CV

 (31)
同理,也将 LS1 CS串联等效为副边电抗器
ZS,其值由下式决定:
B
SS1 S
2
SB
8
1
jjj
j
V
Z
LL
CI

(32)
将式(28)代入式(21)得到附加电容 CSa
2
B
Sa
B
4
I
CV
(33)
(24)—(33)给出了充电电流可配置的变结构
无线充电系统参数设计方法,按照上述计算方法配
置的充电系统,能够实现单个逆变器对多个电动自
行车充电、不同充电电流的电动自行车共享充电
桩,且系统几乎没有无功输入。
4 实验验证
为了验证所提出方法的可行性和有效性,本文
设计并搭建了如图 7所示的两套充电系统样机,
电电压均为 48V,充电电流分别为 2A 4A,表 1
列出了系统的参数和标号(参数下角标的最后一位
表示 2A 4A 充电电流规格的系统)
对于电动自行车铅蓄电池,若额定电压为48V
整流桥 2
逆变器
控制器
CPe4 CP14
LP4
CSa4
LS4
LP14
LS24
CS14
CSe S24
LP12
CP12
CPe2 LP2
LS2
CSe2
CS2
CSa2
整流桥
4
S14
S12
S22
LS24
7 实验原理样机
Fig. 7 The experimental prototype
1 感应式无线充电系统参数
Tab. 1 The configuration of IPT charging system
2A 系统参数 数值 4A 系统参数 数值
直流源电压 E/V 110 直流源电压 E/V 110
频率 f/kHz 500 频率 f/kHz 500
电感 LP12/H 30.36 电感 LP14/H 29.42
电容 CP12/nF 3.35 电容 CP14/nF 3.36
电容 CPe2/nF 2.62 电容 CPe4/nF 3.32
原边线圈自感 LP2/H 56.34 原边线圈自感 LP4/H 56.17
副边线圈自感 LS2/H 34.87 副边线圈自感 LS4/H 35.91
互感 M2/H 14.03 互感 M4/H 14.04
电容 CSe2/nF 3.44 电容 CSe4/nF 3.20
电容 CS12/nF 16.13 电容 CS14/nF 33.22
电感 LS22/H 4.59 电感 LS24/H 3.01
电容 CSa2/nF 37.86 电容 CSa4/nF 61.93
原副边线圈间距 l2/mm 20 原副边线圈间距 l4/mm 20
3340 38
额定电流为 4A,则在恒流充电模式时,系统输出
4A 电流,电池电压逐渐增长,当电池电压上升到
额定电压时,进入恒压模式,系统输出 48V 进行充
电,充电电流逐渐下降,当降至充电截止电流(本实
验取 100mA)时,充电完成。实验中,4A 电池的等
效电阻 RB在整个充电过程中从 9一直增加到
480实验中采用电子负载 IT8518B 模拟电池等效
电阻的变化。48V-2A 的电池类似,在整个充电过
程中电池等效电阻从放电截止电压 36V 时的 18
一直上升到充电截止电流 100mA 时的 480
为了实现逆变器工作在软开关状态,设计电容
CPe2 CPe4 的参数略小于理论值,分别为 2.62nF
3.32nF,使得逆变器输出阻抗呈弱感性,逆变器实
现零电压开通[20]
8所示为 4A 系统独立工作于恒流模式,逆
变器输出电压 up逆变器输出电流 ip充电电压 VB
充电电流 IB的波形。其中图 8(a)电池等效电阻为
9,充电电流 IB4.02A,系统输出功率为
145.44W,系统效率为 87.89%;图 8(b)电池等效电
阻为 12,充电电流 IB4.006A,系统输出功率
192.57W系统效率为 88.65%充电电流变化率
0.35%基本保持恒定。逆变器输出电压 up与电
ip几乎同相位,系统输入无功几乎为零。
t(1s/)
(a) RB9
up
(200V/)
VB
(50V/)
ip, IB
(5A/)
t(1s/)
(b) RB12
up
(144V/)
VB
(50V/)
ip, IB
(5A/)
8 4A系统恒流模式下逆变器输出电压、电流、
充电电压和电流波形
Fig. 8 Experimental waveforms of up, ip, VB2A and IB2A in
constant current mode
9所示为 4A 系统独立工作于恒压模式,逆
变器输出电压 up逆变器输出电流 ip充电电压 VB
充电电流 IB的波形。其中图 9(a)电池等效电阻为
12,充电电压 VB48.004V,系统输出功率为
192.03W,系统效率为 88.48%;图 9(b)电池等效电
阻为 200,充电电压 VB50.7V,系统输出功率
12.77W系统效率为 86.5%充电电压变化率为
5.6%基本保持恒定。逆变器输出电压 up与电流 ip
几乎同相位,系统输入无功几乎为零。
10 所示为恒流充电模式切换到恒压充电模
式时,开关 S1的驱动信号电压 VG_S1、开关 S2的驱
动信号电压 VG_S2、开S1的切换电流 IS1、开S2
的切换电流 IS2、开关 S1的切换电压 VS1、开关 S2
的切换电压VS2充电电压 VB和充电电流 IB的波形。
从中可以看出,充电模式切换之后开关 S1支路的电
t(1s/)
(a) RB12
up
(144V/)
VB
(50V/)
ip, IB
(5A/)
t(1s/)
(b) RB200
VB(50V/) up(144V/)
IB(1A/) ip(5A/)
9 4A系统恒压模式下逆变器输出电压、电流,
充电电压和电流波形
Fig. 9 Experimental waveforms of up, ip, VB and IB in
constant current mode
t(200s/)
(a) 开关支路电流波形
VG_S1, VG_S2
(10V/)
IS1, IS2
(10A/)
11 麦瑞坤等:可配置充电电流的变结构无线充电系统研究 3341
t(200s/)
(b) 开关支路电压波形
VG_S1,2
(10V/)
VS2
(100V/)
VS1
(200V/)
t(200s/)
(c) 充电电流电压波形
VG_S1,2
(10V/)
IB
(5A/)
VB
(50V/)
10 开关 S1S2切换时开关支路电流波形、
开关支路电压波形和充电电流电压波形
Fig. 10 Experimental waveforms of IS1, IS2, VS1, VS2, VB
and IB when switch S1 and S2 switching
压、开关 S2支路的电压电流和充电电压电流的暂态
振荡很小。
11 4A 系统独立工作时,系统效率随电池
等效电阻的自然对数变化的曲线,虚线左侧为恒流
充电模式,右侧为恒压充电模式。12 4A 系统
独立运行时,电池电流和电压随电池等效电阻的自
然对数变化的曲线。
为了验证电子负载可以替代蓄电池以简化分
析,本文采用 4个铅蓄电池(型号为 6-DZM-12)串联
作为负载,使用 2A 系统进行了充电实验。13
采用铅蓄电池充电时系统效率随电池等效电阻的
自然对数变化的曲线;图 14 为用铅蓄电池充电时
充电电流和电压随电池等效电阻的自然对数变化
的曲线。对比图 1214 可以看出,二者的充电曲
电池等效电阻自然对数 lnRB
4A 系统效率
2
0.80
0.84
0.92
0.88
46 3 5
11 4A 系统充电效率随 lnRB变化曲线图
Fig. 11 Measured efficiencies of the IPT charging system
versus lnRB
电池等效电阻自然对数 lnRB
4A 系统充电电流/A
02
1
2
4
3
4 6 35
4A 系统充电电压/V
0
60
20
40
12 4A系统电流电压随电池等效电阻自然对数 lnRB
变化曲线图
Fig. 12 Measured current and voltage of the IPT charging
system versus lnRB
电池等效电阻自然对数 lnRB
系统充电效率
0.7
0.8
0.9
4.0 5.5 3.5 5.0 3.0 4.5
13 采用铅蓄电池充电时 2A 系统效率随电池等效电阻
自然对数 lnRB变化曲线图
Fig. 13 Measured efficiencies of the IPT charging system
versus lnRB using lead-acid battery
电池等效电阻自然对数 lnRB
系统充电电流/A
0.0
0.4
0.8
1.6
4.5 5.5 3.5 5.0
系统充电电压/V
0
20
40
1.2
2.0
10
30
50
4.03.0
14 采用铅蓄电池充电时 2A 系统电流电压随电池等效
电阻自然对数 lnRB变化曲线图
Fig. 14 Measured current and voltage of the IPT charging
system versus lnRB using lead-acid battery
线与图 1所示的电池理论充电曲线基本一致,可见
采用电子负载来模拟电池进行简化分析是可行且
有效的。
15 所示为 2A 系统和 4A 系统同时运行于恒
流充电模式下,逆变器输出电压 up逆变器输出电
ip2A 充电电流 IB2A 4A 充电电流 IB4A 的波形。
2A 系统电池等效电阻和充电电流 IB2A 分别为 20
1.97A4A 系统电池等效电阻和充电电流 IB4A
别为 94.02A。由此得出,单个逆变器可同时
对多个电池充电。此外,两套系统原边电路及耦合
机构的参数基本一致,验证了不同充电电流的电动
自行车可共享充电桩。
3342 38
t(1s/)
IB2A(2A/) up(100V/)
IB4A(4A/) ip(5A/)
15 2A系统和 4A 系统同时运行于恒流模式,RB分别
209时的逆变器输出电压、电流,2A 系统充电电流
4A 系统充电电流
Fig. 15 Experimental waveforms of up, ip, VB, and IB in
constant current mode at RB20 and 9
5 结论
本文基于 LCL 拓扑电路和 SS 拓扑 IPT 系统电
路的恒压输入恒流输出和恒流输入恒压输出特性,
给出了双 LCL 拓扑电路,并提出了在副边电路增加
两个开关和一个附加电容的方法,以实现单个逆变
器对多个电动自行车充电。不同充电电流的电动自
行车可以共享充电桩且系统无功输入几乎为零。
实验中系统恒流充电时,4A 系统的充电电流恒定
4A,变化率为 0.35%;在系统恒压充电时,4A
系统的充电电压恒定在 48V,变化率为 3.5%2A
系统和 4A 系统并联于单个逆变器时均能正常工
作;采用电子负载和铅蓄电池充电的充电曲线基本
一致,实验中用电子负载替代蓄电池是可行的。
验结果表明,本文搭建的 2A 系统和 4A 系统原理
样机成功模拟了单个逆变器对多个电动自行车充
电和不同充电电流的电动自行车共享充电桩,故本
文提出的方法有效且可行。
参考文献
[1] 范兴明,莫小勇,张鑫.无线电能传输技术的研究现状
与应用[J]中国电机工程学报,201535(10)2584-2600
Fan XingmingMo XiaoyongZhang XinResearch status
and application of wireless power transmission
technology[J]Proceedings of the CSEE201535(10)
2584-2600(in Chinese)
[2] 张献,杨庆新,陈海燕,等.电磁耦合谐振式无线电能
传输系统的建模、设计与实验验证[J]中国电机工程学
报,201232(21)153-158
Zhang XianYang QingxinChen Haiyanet alModeling
and design and experimental verification of contactless
power transmission systems via electromagnetic resonant
coupling[J]Proceedings of the CSEE201232(21)
153-158(in Chinese)
[3] Li YongMai RuikunLu Liwenet alActive and reactive
currents decomposition-based control of angle and
magnitude of current for a parallel multiinverter IPT
system[J]IEEE Transactions on Power Electronics
201732(2)1602-1614
[4] 麦瑞坤,李勇,何正友,等.无线电能传输技术及其在
轨道交通中研究进展[J].西南交通大学学报,2016
51(3)446-461
Mai RuikunLi YongHe Zhengyouet alWireless power
transfer technology and its research progress in rail
transportation[J] Journal of Southwest Jiaotong
University201651(3)446-461(in Chinese)
[5] Sallan JVilla J LLlombart Aet alOptimal design of
ICPT systems applied to electric vehicle battery
charge[J]IEEE Transactions on Industrial Electronics
200956(6)2140-2149
[6] Jang YJovanović M MA contactless electrical energy
transmission system for portable-telephone battery
chargers[J]IEEE Transactions on Industrial Electronics
200350(3)520-527
[7] 麦瑞坤,马林森.基于双拾取线圈的感应电能传输系统
研究[J]中国电机工程学报,201636(19)5192-5199
Mai RuikunMa LinsenResearch on inductive power
transfer systems with dual pick-up coils[J]Proceedings of
the CSEE201636(19)5192-5199(in Chinese)
[8] 石臣鹏.电动自行车交通现状及对策分析[J]重庆交通
大学学报:自然科学版,200827(5)772-775
Shi ChenpengAnalysis on electric bicycles current
traffic situation and countermeasures[J] Journal of
Chongqing Jiaotong UniversityNatural Science2008
27(5)772-775(in Chinese)
[9] 麦瑞坤,陈阳,刘野然.基于变补偿参数的 IPT 恒流恒
压电池充电研究[J]中国电机工程学报,201636(21)
5816-5821
Mai Ruikun Chen YangLiu YeranCompensation
capacitor alteration based IPT battery charging application
with constant current and constant voltage control[J]
Proceedings of the CSEE201636(21)5816-5821(in
Chinese)
[10] Mai RuikunChen YangLi Yonget alInductive power
transfer for massive electric bicycles charging based on
hybrid topology switching with a single inverter[J]IEEE
Transactions on Power Electronics 2017 32(8)
5897-5906
[11] Buja G Bertoluzzo MMude K NDesign and
experimentation of WPT charger for electric city car[J]
IEEE Transactions on Industrial Electronics 2015
62(12)7436-7447
[12] Li HongchangLi JieWang Kangping
et alA maximum
efficiency point tracking control scheme for wireless
11 麦瑞坤等:可配置充电电流的变结构无线充电系统研究 3343
power transfer systems using magnetic resonant
coupling[J]IEEE Transactions on Power Electronics
201530(7)3998-4008
[13] Wang C SStielau O HCovic G ADesign considerations
for a contactless electric vehicle battery charger[J]IEEE
Transactions on Industrial Electronics200552(5)
1308-1314
[14] Vu V BDoan V TPham V Let alA new method to
implement the constant current-constant voltage charge of
the inductive power transfer system for electric vehicle
applications[C]//Proceedings of IEEE Conference and
Expo Transportation Electrification Asia-Pacific (ITEC
Asia-Pacific)BusanIEEE2016449-453
[15] Wu H HGilchrist ASealy K Det alA high efficiency
5kW inductive charger for EVs using dual side control[J]
IEEE Transactions on Industrial Informatics20128(3)
585-595
[16] Boys J TCovic G AXu YongxiangDC analysis
technique for inductive power transfer pick-ups[J]IEEE
Power Electronics Letters20031(2)51-53
[17] 麦瑞坤,陈阳,张友源,等.基于变次级补偿参数的感
应式无线充电系统研究[J].中国电机工程学报,2017
37(11)3263-3269
Mai RuikunChen YangZhang Youyuanet alStudy on
secondary compensation capacitor alteration based IPT
charging system[J]Proceedings of the CSEE2017
37(11)3263-3269(in Chinese)
[18] Qu XiaohuiHan HongdouWong S Cet alHybrid IPT
topologies with constant current or constant voltage output
for battery charging applications[J]IEEE Transactions on
Power Electronics201530(11)6329-6337
[19] Hao HaoCovic G ABoys J TA parallel topology for
inductive power transfer power supplies[J] IEEE
Transactions on Power Electronics 2014 29(3)
1140-1151
[20] Li SiqiLiu ZheZhao Hanet alWireless power transfer
by electric field resonance and its application in dynamic
charging[J]IEEE Transactions on Industrial Electronics
201663(10)6602-6612
收稿日期:2017-03-21
作者简介:
麦瑞坤(1980)男,副教授,博士生导
师,主要研究方向为无线电能传输在轨道
交通中的应用,mairk@swjtu.edu.cn
张友源(1994)男,硕士研究生,研究
方向为无线电能传输技术;
陈阳(1992)男,博士研究生,研究方
向为无线电能传输技术。
麦瑞坤
(责任编辑 李泽荣)
... Based on a 2-coil resonant tank, achieving CV output is available [15][16][17][18][19][20][21][22], some of which utilize the control method while others adopt elaborate topology. For instance, by implementing two dc-dc converters, where the boost converter after the rectifier circuit for impedance match and the buck converter before the inverter for input voltage conversion, voltage regulation could be performed by manipulating these two dc-dc converters [15]. ...
... Transfer efficiency for the whole system is shown in Equation (15), which is the multiplication of the three efficiencies above. The components R1_23, R3_2 in the numerator are illustrated in Equation (16), and R represents the equivalent load, as = 8 / . ...
... Transfer efficiency for the whole system is shown in Equation (15), which is the multiplication of the three efficiencies above. The components R 1_23 , R 3_2 in the numerator are illustrated in Equation (16), and R represents the equivalent load, as R = 8R L /π 2 . ...
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