is now part of - · pdf filean-9742 半桥焊机功率器件(igbt

14
To learn more about ON Semiconductor, please visit our website at www.onsemi.com Is Now Part of ON Semiconductor and the ON Semiconductor logo are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.

Upload: leminh

Post on 20-Mar-2018

281 views

Category:

Documents


16 download

TRANSCRIPT

Page 1: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

To learn more about ON Semiconductor, please visit our website at www.onsemi.com

Is Now Part of

ON Semiconductor and the ON Semiconductor logo are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries. ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.

Page 2: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

www.fairchildsemi.com

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11

AN-9742

半桥焊机功率器件(IGBT与二极管)的选型指南

摘要

为了减小系统,提高效率,低压/大电流DC-ARC焊机中

使用了不同的拓扑结构,包括双开关正激、半桥和全桥

变换器;其中,在容量低于230A的焊机中,半桥变换器

由于其较小波形因数而被广泛使用。在额定功率下,与

全桥拓扑结构相比,半桥变换器需要更多的变压器绕线

和更大的逆变器电流容量,但是只需要较少的功率器

件。本文以飞兆半导体的评估板为例,给出了一种半桥

式焊机应用中器件选型指南。

焊机概述

一般地,可以根据焊机类型计算输出电压,如表1所

示。

Table 1. 焊机的输出电压

焊机 输出电压 范例

二氧化碳 0.04•IAC+15 0.04•200A+15=23V

钨极惰性气体

保护电弧焊 0.04•IAC+10 0.04•200A+10=18V

直流电弧 0.04•IAC+20 0.04•200A+20=28V

焊机的负载持续率

在焊接工业中,负载持续率是指在10分钟周期内,

保证未过热和电源未烧毁的情况下,焊机在最大额定输

出时的可运行分钟。比如,负载持续率为60%的140A的

焊机在以最大额定输出电流140A连续焊接6分钟后至少

需要休息4分钟。

允许的负载持续率

如果工作时的有效电流比额定输出电流小,焊机的

内部发热会降低。此时,焊机可以工作在比指定负载

持续率高的状态。它的允许负载持续率可以根据下式

计算:

machine weldingof cycleduty currentoutput using

currentoutput rated2

(1)

例如,由于焊接3.2的焊条时,只需要80A到130A的电

流,此时,负载持续率为60%的140A的焊机可以工作

更长。假设焊接3.2的焊条时的电流为100A,实际负载

持续率高于78.4%。

除了实际输出电流,温度也影响焊机的允许负载持续

率。不要使焊机过热。

Table 2. 焊机的可行焊接材料

焊机 气体 焊接类型钢

二氧化碳 二氧化碳 低碳,高张力

金属焊条惰性气体

(水下焊接) 氦+氩 铝,不锈钢,铝合金

熔化极活性气体保护焊 薄金属,低合金,高张力

直流钨极惰性气体保护焊 不锈,低碳,铜合金,镍合金,钛合金,低合金

交流钨极惰性气体保护焊 铝合金,镁合金,Bass

混合钨极惰性气体保护焊 轻合金,复合板

直流电弧 钢,有色金属

交流电弧 铝

Page 3: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 2

飞兆半导体直流电弧焊机评估板

评估板特征

输入级:50A桥用二极管(600V/50A/方桥)

输入滤波级:设计时考虑到传导噪声和辐射噪

控制器:PIC16F716(8-位 ADC和10-位PWM)

逆变器电路:FGH40N60SMD(在Co-Pak二极

管内)单只或并联

输出整流器:FFA60UP30DN *6单元(三个超

快二极管并联)

门极驱动器:开关器件和控制器实施光电耦合

隔离,IGBT门极电压采用+15V、-5V双电源供

AUX电源供应:较低待机消耗的绿色集成PWM

芯片

输入电压和频率:220V VAC 60Hz

输出电压(VOUT)和输出电流(IWEL): 26VDC, 140A

效率:>80%

待机功率:< 4W

开关频率:20KHz

图2 给出了焊机评估板的主电路框图。DC-ARC焊机评

估板的输出电流和输出电压分别为26V和140A,构成了

3kW功率等级的焊机。焊机使用了一系列的飞兆半导体

器件完成设计要求。焊机的开关频率为20kHz。考虑到

尺寸,变压器和电感装在了电路板附近。还装有一个散

热用风扇。

Figure 1. 评估板

H

N

220VAC

Input

DC Link

Capacitor Half-Bridge Inverter

DC

Output~

~

+-

~

~

+-

Power Supply

N

Q

QSET

CLR

D

Bridge

Diode

Control

Output Rectifier

+

-

FSGM0465R

PIC16F716 (micro-controller)

40Khz20Khz

PWM

controller

Inverter Driver (Opto-Coupler)

EMI

Filter

Figure 2. 主框图

Page 4: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 3

半桥逆变器设计

半桥拓扑结构中,变压器的初级与次级匝数比的计算公

式为:

4

)(

1

SWe

MAXMININ

fAB

DVN

(1)

)(

)(

11

MININMAX

IFO

VD

NVVVN

(2)

式中,VI 即 VS,IWEL为输出电流,Id1 与Id2为二极管电

流(输出高端和输出低端)。

空载条件下的输出电压为:

MAX

IFOnolaod

D

VVVV

(3)

式中,

VO为输出电压;

VF为二极管跌落电压;

VI为电感跌落电压。

变压器初级和次级电流的计算公式为:

MAXWELrms DIN

NI 2

1

21 (4)

MAXWELrms DII 212

12 (5)

流过IGBT和次级整流二极管的电流为:

WELIN

IGBT 1

2D

NI :Current (6)

输出整流二极管的电压和电流为:

22

21)( ,

1

2ddWELMAXINr IIIV

N

NV (7)

焊机用IGBT选型

在众多的功率开关器件中,绝缘栅双极晶体管

(IGBT)由于其大电流能力和高开关速度,成为了焊

机最合适的器件。IGBT与功率MOSFET在机理和构造

上相似,是一种电压控制型功率晶体管。该器件具有比

双极晶体管更优越的性能。由于可在大功率和较宽的频

率范围内应用,使之成为了最为经济的选择。表3给出

了IGBT和BJT、MOSFET的特性比较。

Table 3. 器件特性的比较

特点 BJT MOSFET IGBT

驱动方法 电流 电压 电压

驱动电路 复杂 简单 简单

输入阻抗 低 高 高

驱动功率 高 低 低

开关速度 慢(µs) 快(ns) 中等

工作频率 低 快(低于1MHz) 中等

安全工作区 窄 宽 宽

饱和电压 低 高 低

IGBT的功率损耗包括导通损耗和开关损耗。导通损耗

取决于IGBT的Vce(sat)值和占空比。开关损耗取决于IGBT

开关瞬态时的开通和关断行为。IGBT在Vce(sat)具有特定

的平衡特性。当Vce(sat)高时,开关损耗低;反过来亦

然。因此,设计者应该基于系统结构和其开关频率选择

IGBT。IGBT的总损耗可以描述为:

总损

耗 =

单脉冲开关损耗

(EON + EOFF) X 开关频率 +

通态损耗(VCS(SAT) X

IC X 占空比) (8)

Page 5: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 4

图3中的曲线给出了传统型(PT) IGBT和场截止型

(field-stop)IGBT的特性对比。PT IGBT具有负温度系

数特性:当温度升高时,Vce(sat)减小。Field-stop IGBT具

有正温度系数特性:当温度升高时,Vce(sat)增大。因

此,当IGBT单独使用时,具有负温度系数特性的PT

IGBT更加合适。当使用IGBT并联分流时,具有正温度

系数特性的Field-stop IGBT将更加合适。

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

0

10

20

30

40

50

60

70

80

FGH40N60SMD

FGH40N60UFD

FGH40N60SFD

HGTG20N60A4D

Co

lle

cto

r C

urr

en

t, I

c[A

]

Collector-Emitter Voltage, Vce(sat)[V]

Tc=25deg.C

Vge=15V

Figure 3. HGTG20N60A4D(PT) vs. FGH40N60UFD/SFD (场

截止1代)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

0

10

20

30

40

50

60

70

80

Co

lle

cto

r C

urr

en

t, I

c[A

]

FGH40N60SMD

FGH40N60UFD

FGH40N60SFD

HGTG20N60A4D

Tc=125deg.C

Vge=15V

Collector-Emitter Voltage, Vce(sat)[V]

Figure 4. FGH40N60SMD (场截止2代)

鉴于具有更好的热力性能,减少导通损耗和降低整体器

件成本,便于IGBT并联工作。无论如何,在这种应用

中需要考虑以下几点:

使用耐高温、正温度系数特性的IGBT

确保IGBT门极电阻误差≤1%

合适的门极PCB布局,确保获得对称的电流路径

IGBT具有完全相同的散热器规格和风扇

相同的阀值电压与饱和电压特性

下图给出了在25kHz以及更高的开关频率范围时,开关

损耗超过导通损耗,成为主要损耗因素。

10 20 30 40

0.0

0.5

1.0

1.5

2.0

Test Condition :

Vcc=400V, Rg=10 ohm, Vge=15V

Tc=25deg.C

Tc=125deg.C

FGH40N60SMD

FGH40N60UFD

FGH40N60SFD

HGTG20N60A4D

To

tal S

wit

ch

ing

Lo

ss

[Eo

n+

Eo

ff],

Ets

[mJ

]

Collector Current, Ic[A]

Figure 5. 总开关损耗Ets vs. 集电极电流IC

20.0k 40.0k 60.0k 80.0k 100.0k

0

50

100

150

200

250

Test Condition :

Vcc=400V, Rg=10 ohm,

Vge=15V, Ic=40A, Tc=125deg.C

FGH40N60SMD

FGH40N60UFD

FGH40N60SFD

HGTG20N60A4DT

ota

l p

ow

er

los

s o

f IG

BT

, P

d [

W]

Switching Frequency, Fsw[KHz]

Conduction loss

Switching lo

ss[ Eon+ Eoff]

Total power lo

ss

Figure 6. IGBT的总功率损耗Pd vs. 开关频率

对于开关损耗,门极电阻是非常关键的。较大门极电阻

会导致较高开关损耗。另一方面,由于较大门极电阻时

开关瞬态di/dt更低,故可提高EMI性能。适当的门极电

阻应该在满足系统EMI性能要求的前提下,具有最小的

开关损耗。

Page 6: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 5

下图给出了JIG测试中测得的IGBT关断特性。在相同的

条件下,比较采用先前技术的器件——PT和FS平面一

代IGBT 相比,FS平面二代IGBT FGH40N60SMD表现出

了更快的开关特性、更低的Vce(sat)和惊奇的低关断损

耗。

5 10 15 20 25 30

0.2

0.4

0.6

0.8

1.0

Test Condition :

Vcc=400V, Ic=40A, Vge=15V

FGH40N60SMD

FGH40N60UFD

FGH40N60SFD

HGTG20N60A4D

Tc=25deg.C

Tc=125deg.C

Sw

itc

hin

g L

os

s, E

off[m

J]

Gate Resistance, Rg[ohm]

Figure 7. 关断损耗EO vs. 门极电阻Rg

1.6 1.8 2.0 2.2 2.4

8

12

16

Tc=25deg.C

FGH40N60SMDFGH40N60SFD

HGTG20N60A4D

FGH40N60UFD

Collector-Emitter Voltage, Vce(sat)[V]

Sw

itc

hin

g lo

ss

, E

off / A

[uJ

]

Figure 8. 关断损耗 EOFF vs. 集电极-发射极电压 Vce(sat)

图9和图10给出了评估板在电阻负载和焊接负载下得

IGBT工作波形。这些波形说明,焊接负载消耗的电流

为电阻负载的3倍。因此,需要选择具有合适参数Icm的

IGBT,避免在峰值电流条件下出现饱和,这点是非常

重要的。

Vge_H : 5V/div

ID : 20A/div

Vge_L : 5V/div

Vce_L : 100V/div

4µs/div

Figure 9. 在IOUT=14A下的电阻负载测试

Vge_H : 5V/div

ID : 50A/div

Vge_L : 5V/div

Vce_L : 100V/div

4µs/div

Figure 10. 3.2 Pie型焊条下的焊接负载测试 Pie型

Page 7: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 6

图11到图16给出了焊机负载和电阻负载下测得的关断开

关损耗EOFF。考虑到漏感和电容的因素,与JIG测试结果

相比,EOFF的测量结果具有很大的不同。根据测试,

FGH40N60SMD的EOFF表现出了最低的损耗。

Eoff: 5.03mJ

ID : 20A/div

Vge_L : 5V/div

Vce_L : 100V/div

400ns/div

Eoff: 5.476mJ

ID : 20A/div

Vge_L : 5V/div

Vce_L : 100V/div

400ns/div

Eoff: 5.927mJ

ID : 20A/div

Vge_L : 5V/div

Vce_L : 100V/div

400ns/div

Figure 11. 电阻负载下的EOFF的比较

(FGH40N60SMD)

Figure 12. 电阻负载下的EOFF的比较

(FGH40N60UFD)

Figure 13. 电阻负载下的EOFF的比较

(FGH40N60SFD)

Eoff: 36.13mJ

ID : 50A/div

Vge_L : 5V/div

Vce_L : 100V/div

1us/div

Eoff: 37.81mJ

ID : 50A/div

Vge_L : 5V/div

Vce_L : 100V/div

1us/div

Eoff: 42.88mJ

ID : 50A/div

Vge_L : 5V/div

Vce_L : 100V/div

1us/div

Figure 14. 焊接负载下的EOFF的比较

(FGH40N60SMD)

Figure 15. 焊接负载下的EOFF的比较

(FGH40N60UFD)

Figure 16. 焊接负载下的EOFF的比较

(FGH40N60SFD)

Page 8: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 7

焊机用整流二极管

飞兆半导体为不同的应用提供五种二极管。低Vf、Irr和

Trr特性的二极管为焊机应用中最理想选择;但是一般的

P_N理论指出,Vf越低,Trr越长,反之亦然。设计者选

择二极管时,应找到Vf、Trr的平衡点,来使得系统效率

最大。下图给出了每一种飞兆半导体二极管技术的

600V/8A二极管的性能比较。

0 20 40 60 80

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

Stealth2 Ulrafast

Hyperfast

Hyperfast2

Stealth

Stealth2

Stealth

Hyperfast2Hyperfast

Ultrafast

Tc=25deg.C

VF

[V

]

Qrr [nC]

FCS Rectifier Diode Vf vs Qrr, 600V 8A

Figure 17. VF vs. Qrr 权衡考虑

-80.0n -40.0n 0.0 40.0n 80.0n 120.0n 160.0n-12

-10

-8

-6

-4

-2

0

2

4

6

8

10

Tc=125deg.C

IF [

A]

Time [sec]

Ultrafast

Hyperfast

Hyperfast2

Stealth

Stealth2

FSC Rectifier performance @ 600V, 8A

Figure 18. 反向恢复特性

L

RG

Vge

DUTCURRENT

SENSE

IGBT

Test Circuit and Waveforms

VDD

Figure 19. 测试电路和波形

rrrrrr tIQ 2

1 (9)

一般的,焊机的整流二极管的导通损耗高于反向恢复损

耗。因此,焊机应用中,二极管的VF值更加关键。鉴于

此,评估板使用了超快二极管FFA60UP30DN(30A双

二极管)。变压器的每个抽头并联三个二极管来降低

VF。

下图给出了单个使用和并联使用的二极管的特性。尽管

反向恢复损耗有所增加,并联使用可以获得较低的VF,

并且具有更好的散热性能。对于二极管并联应用,鉴于

温度升高时,二极管的VF会降低,因此设计者应该确保

气流不会引起电流不均衡条件。

0.0 0.6 1.2 1.8

0

20

40

60

80

100

Tc=25deg.C

Tc=125deg.C

VF, Forward Voltage [V]

FFA60UP30DN-Dual

FFA60UP30DN-single

IF, F

orw

ard

Cu

rre

nt

[A]

Diode I-V charateristic

Figure 20. 二极管I-V特性曲线

100 200 300 400 500

0

60

120

180

240

300

360FFA60UP30DN Qrr charateristic

Tc=25deg.C

Tc=125deg.C

Sto

red

Re

co

ve

ry c

ha

rge

Qrr [

nC

]

di/dt [ A/us]

VR = 150V

IF = 30A

Single

Dual

Figure 21. 存储恢复电荷 Qrr vs.

二极管电流斜率 di/dt

Page 9: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 8

图22给出了电路板工作频率为20kHz时的二极管开关损耗。通

态损耗约为336µJ,反向恢复损耗仅为4µJ左右。

10µs/div

IWEL: 50A/div

V1 : 2V/div

Econ=368.8uJ

VD1 : 10A/div

Figure 22. 焊接过程中的二极管导通损耗

200ns/div

IWEL: 50A/div

V1 : 50V/div

Econ=3.908uJ

VD1 : 1A/div

Figure 23. 焊接过程中的二极管反向恢复损耗

当某一二极管反向电压超过指定Vr值时,二极管将发生

雪崩现象,电流急剧增加。二极管并未失效的区域

(Vr(AVL)*Isa)称为雪崩能量,其方程为:

])(

[2

1

)(

)(2

DDAVLr

AVLr

saAVL

VV

VILE

)()( )(1 AVLrces VDUTBVIGBTQ

(10)

如方程所示,雪崩能量由第二电感提供。其抗扰能力与

电感量成正比。焊机电感一般设计值小到几µH,二极

管的这种抗扰能力属于选择器件的一个重要因素。

焊机的次级整流可能发生雪崩现象,尤其当焊机已经工

作结束且电感反向导通时。图24给出了抗扰能力测量电

路,图25给出了雪崩能量测试结果波形。

Q1

DUT(FFA60UP30DN)

Current

Sense

L=50µH

+

-

Figure 24. UIS 测试电路

4µs/div

Isa: 116.8A

Vr(AVL): 432.0V

EAVL=314.8mJ

Figure 25. FFA60UP30DN 抗扰能力

隔直电容

对于半桥拓扑结构,如果两种直流电容或者IGBT

的开通时间不匹配,变压器中会出现直流磁通。直

流磁通累积会导致变压器饱和。这将引起电流急剧

增大,并烧毁IGBT。为了抑制变压器铁芯的直流

磁通,可以在变压器初级串联一个较小的隔直电

容。隔直电容的计算公式为:

swP

D

blocking

FV

IDC

max

(11)

式中, PV 为初级电压中允许的电压跌落,该电压由隔

直电容引起。

下图为变压器初级电流波形。直流偏置将引起变压器

饱,并导致电流突然增大。

Vce_H: 50V/div

Vce_L : 50V/div

ID : 20A/div

100µs/div

* saturation current

Figure 26. IGBT 的饱和电流

Page 10: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 9

Figure 27. IGBT 饱和电流的放大效果

电源结构与设计

电源中使用了集成MOSFET芯片FSMG0465R。外围电

路简单,开关频率为66kHz,这样大大减小了PCB和变

压器尺寸。另外,待机模式(230VAC输入,0.5W负载

下的功率<1W)下的功耗较低,使得待机耗电量较小,

从而获得了最大的电源效率。也可以采用变压器类型和

开关电源(SMPS)类型做为替代电源。与线性变压器

类型的电源相比,即使在输入电源出现间断、跌落或者

噪声时,SMPS类型电源仍然具有稳定的输出功率,并

且可设计出最小尺寸和重量。此外,变压器类型需要固

定的输入电压,但是SMPS输入电压可在80VAC~264VAC

范围内变化,这使得它可用在各种焊机中,而无需额外

操作。不管怎样,开关噪声将会影响主逆变器,因此需

要考虑防止干扰措施。关于飞兆半导体开关(FPS™)的

更多信息,请参考应用笔记AN-4150,浏览地址:

http://www.fairchildsemi.com/an/AN/AN-4150.pdf.

控制器设计

评估板控制电路使用了PIC16F716。该控制器包括4个8-

位AD转换器端口和1个9-位40kHz分辨率的PWM定时器

端口。为了从一路PWM信号中获得两路PWM脉冲,内

部使用了一个D触发器和一个与门,将40kHzPWM脉冲

分频为20kHz的PWM脉冲(参见图28)。

Low Side Gate PWM (20KHz)

Controller PWM(40KHz)

High Side Gate PWM (20KHz)

Figure 28. PWM 40kHz分频为20kHz

门极驱动器设计

门极驱动器可以使用变压器、光电耦合器或者HVIC。

不同类型的门极驱动所需电源电压列表如下

HVIC驱动器:+15V, 0V(高电平与低电平),

+ 24V, 0V(输出检测),+5V, 0V(控制器)

光电耦合驱动器:+15V, 0V, -5V(高端门极)

+15V, 0V, -5V(低端门极),+24V, 0V(输出检测),

+5V, 0V(控制器)

脉冲变压器:+24V, 0V(输出检测)+5V, 0V(控制器)

光电耦合和变压器可以在控制电路和IGBT提供电气隔

离。然而,由于门极脉冲死区时间电路出现的偏差电

压,变压器可能会导致半桥电路出现交叉导通。通过使

用集成高压MOSFET,HVIC可以在控制电路和高压侧

IGBT之间建立绝缘。这在负电源电压时是行不通的。

在快速换流中,HVIC需要负电源电压,可以防止dv/dt

变化引起的直通。直通的出现与两个IGBT中的任意一

个快速电压变化有关。由于米勒效应,当IGBT关断

时,流经集电极-发射极间电容的电流会引起IGBT门极

电压上升,并引发桥臂出现交叉导通。

C11

10uF/10V

C19104

C20104

D1

1N4937

D2

1N4937

D3

1N4937

-15V

C21104

D4

1N4937

C822P

+15V

+15V

C22104

-15V

J2

Output 12

RD2

ERR

Y1

WLD

C3104

J1

Current Limit

123

C23104

R8

10k R91k

VR35k

VR15k

C6

105

G3

PWR

R6

1K

R13 330

R12 330

Temp

+5V

+5V

J3

CT 12

C4104

R11 330

D5

1N4937

U2A

7474

CLK3

CLR

1

D2

PR

E4

Q5

Q6

U1 PIC16C711

GN

D5

VD

D14

OSC2/CLKOUT15

MCLR/VPP4

OSC1/CLKIN16

RA0/AN017

RA1/AN118

RA2/AN21

RA3/AN3/VREF2

RA4/TOCKI3

RB0/INT6

RB17

RB28

RB39

RB410

RB511

RB612

RB713

J1

TH 12

R110 ohm/3W

X1

20Mhz

C1

22uF/10V

U5

PS25012

35

8

4

6

U6

PS25012

35

8

4

6

VR25k

R20330

ZD!

1N4099

12

R2

27k

U3A

7409

1

23

R3

1k

U4B

7409

4

56

C2104

R19330

R101K

C7104

+5V

C922P

+5V

+5V

+5V

R16 330

R15 330

R14 330

+5V+5V +5V

C12104

+5VBD1

1

2

Gate2_1

C15104

C16104

gate2_2

+5V

RD1SD

G2

Cont-

G1

Cont+

+5V

gate1_2

Gate1_1

R18 1K

R17 1K

C13470P

C14470P

R71K

LVD

R4

36k

C5104

+5V

+5V

R5

560

Q2

2n3904d/ON

Q1

2n3904d/ON

Temp

C10104

PC1PC817

12

43

Figure 29. 控制电路

Page 11: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 10

IGBT

CCG

CGE

RG

C

E

dtdVGI CGCG /

ICG

dv/dt

dV/dt

Vce

ICG

VgeCGgge IRV

CGCG CdtdvI /

Figure 30. dV/dt 对VGE的影响

Low side gate

High side gate

Current

Figure 31. dV/dt 对门极波形的影响

基于以上基本考虑,本焊机评估板采用了光电耦合器。

图32和图33给出了不同类型驱动的门极波形。显然,本

焊机采用光电耦合器属于最佳选择。

Low Side Gate wave

High Side Gate wave

Figure 32. HVIC 门极波形

Low Side Gate wave

High Side Gate wave

Figure 33. 变压器门极波形

Figure 34. 光电耦合器门极波形

直流电抗器设计

直流电抗器有助于稳定焊机运行中的弧电流。随着直流

电抗器的增大,电弧变小。相反地,如果电弧灵敏度降

低,LDC又太大,就很难产生电弧。因此,选择合适的

电抗器很必要。如果将VOPEN作为空载输出电压,VWEL

和 IWEL 作为额定输出电压和额定输出电流,可得LDC最

大值为:

:

)1( RV

IIn

tRL

open

WEL

R

DC

(12)

式中,R为焊机负载的等效电阻,Tr 为输出电流由零升

到额定电流的上升时间。一旦得到LDC最大值,则可以

通过实验最终确定最佳的LDC取值。

Figure 35. 焊机工作过程中软启动

IWEL: 50A/div

ID : 50A/divVge_L : 5V/div

Vce_L : 50V/div

100us/div

Figure 36. 焊机工作

Page 12: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 11

结论

根据逆变器拓扑和开关频率,一旦逆变器的功率器件得

到正确选型,DC-ARC焊机可以获得更好的性能。本文

给出了半桥焊机应用的功率器件选型指南。

当选用IGBT时,设计者应该注意其Vce(sat)、Eoff关断损

耗、门极驱动电阻以及Icm特性等关键因素。

选择次级整流二极管时,需要关注Vf 和反向恢复损耗之

中哪一个为主导因素,这取决于系统的开关频率。本评

估板在变压器的每一个抽头上并联了三个超快速二极管

(FFA60UP30DN),用来降低Vf,同时带来导通损耗降

低。

参考文件

[1] Aspandiar, Raiyo, “Voids in Solder Joints,” SMTA Northwest Chapter Meeting, September 21, 2005,

Intel® Corporation.

[2] Bryant, Keith, “Investigating Voids,” Circuits Assembly, June 2004.

[3] Comley, David, et al, “The QFN: Smaller, Faster, and Less Expensive,” Chip Scale Review.com, August /

September 2002.

[4] Englemaier, Werner, “Voids in solder joints-reliability,” Global SMT & Package, December 2005.

[5] IPC Solder Products Value Council, “Round Robin Testing and Analysis of Lead Free Solder Pastes with Alloys of

Tin, Silver, and Copper,” 2005.

[6] IPC-A-610-D, “Acceptance of Electronic Assemblies,” February 2005.

[7] IPC J-STD-001D, “Requirements for Soldered Electrical and Electronic Assemblies.”

[8] IPC-SM-7525A, “Stencil Design Guidelines,” May 2000.

[9] JEDEC, JESD22-B102D, “Solderability,” VA, Sept. 2004.

[10] Syed, Ahmer, et al, “Board-Level Assembly and Reliability Considerations for QFN Type Packages,”

Amkor Technology, Inc., Chandler, AZ.

相关资源

FGH40N60SMD — 600V, 40A Field Stop IGBT

FFA60UP30DN — 300V Ultrafast Recovery Power Rectifier

FSGM0465R — SMPS Power Switch, 4A, 650V (Green)

附件-电路图

C5110uF 630V

2

T1

TRANSFORMER CT

1 5

6

4 8

D3 FGA60UP30DN

D7 FGA60UP30DN

D16 FGA60UP30DN

D17 FGA60UP30DN

D18 FGA60UP30DN

D19 FGA60UP30DN

R6

10

- Output

C23

102

R39

10

C24

102

+ Output

ZD81N4744

ZD91N4733

R54.7k

Gate1

Gate2

C5210nF 630V

ZD71N4733

R44.7k

ZD31N4744

ZD41N4733

Z4

FGA40N60SMD

R9 10/3W

C5310nF 630V

Z2

FGA40N60SMD

R3 10/3W

GND1

ZD61N4744

C541uF M275V

C55472M

C62472M RV1

20D431K

RV220D431K

RV320D431K

P10

1

P11

1

P3

1

L6

L5

LF1RFILTER

L4 52uHC2

400V 560uF

Z3FGA40N60SMD

Z1FGH40N60SMD

R8 10/3W

R74.7k

R1 10/3WZD11N4744

ZD21N4733

R24.7k

- +

BD1

GBP5006

2

1

3

4C1

400V 560uF

- BUS

C61

630V

+ BUS

GND2FAN

1

Gate1

Gate2

C5010uF 630V

CT1

JF3250G

1 3

Figure 37. 主电路

Page 13: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

AN-9742 APPLICATION NOTE

© 2011 Fairchild Semiconductor Corporation www.fairchildsemi.com Rev. 1.0.0 • 12/2/11 12

L2 10uH

XY

4.7nF/1KV

R204

1K

F201 250V 2A

U201 FGM0465R

FB4

Drain1

GN

D2

Vstr6

Vcc3

R2011M/1W

C214

47nF

R217

1.2k

C216

1000uF 10V

D202

1N4007

D203

MBRF10H100

- +

BD201

2KBP06M3N25

2

1

3

4

R219

8K

R208

1k

C213

102

C224470uF 35V

R2051K

C207

47uF 50V

PC1

12

R215

10

U202TL431

23

1

D201

UF4004

LF201

30mH

D204

MBRF10H100

L1 10uH

R218

18K

C202275Vac 100nF

C215

470uF 10V

C2083.3nF 630V

R202

270K

PC2 817

12

43

C204

47nFD38

1N4744 1

2

D206

MBRF10H100

T101EER3940S

13

7

8

9

10

11

12

14

15

16

3

1

TNR10D471k

C209 102

R216

620

C210

102

L5

4.9uH

C203400V 100uF

R212

10

ZD2011N4745A

1

2

C223

470uF 35V

+15v

gnd

5v

AC220V H

AC220V N

-15V

GND2

C201275Vac 100nF

R20743K/1W

R20675K

C20533nF 100V

C206

100nF

R210

1W 5

R220

8K

R203150K

Q201

2N2222

R211 10

NTC

NTC1

5D-9

R209

100 ohm/0.5W

GND1

L4 10uH

D205

MBRF10H100C220

470uF 35V

D207

MBRF10H100

L3 10uH

C211102

C212102R214 10

C219470uF 35V

15+v

-15V

R21310

C217

470uF 35VC218

470uF 35V

C211470uF 35V

C222470uF 35V

Figure 38. 辅助电源

Figure 39. 控制器

DISCLAIMER

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN

TO IMPROVE RELIABILITY, FUNCTION, OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE

APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS

PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS

WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION.

As used herein:

1. Life support devices or systems are devices or systems which, (a)

are intended for surgical implant into the body, or (b) support or

sustain life, or (c) whose failure to perform when properly used in

accordance with instructions for use provided in the labeling, can

be reasonably expected to result in significant injury to the user.

2. A critical component is any component of a life support device or

system whose failure to perform can be reasonably expected to

cause the failure of the life support device or system, or to affect its

safety or effectiveness.

Page 14: Is Now Part of -   · PDF filean-9742 半桥焊机功率器件(igbt

www.onsemi.com1

ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patentcoverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liabilityarising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/orspecifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customerapplication by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are notdesigned, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classificationin a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorizedapplication, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, andexpenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if suchclaim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. Thisliterature is subject to all applicable copyright laws and is not for resale in any manner.

PUBLICATION ORDERING INFORMATIONN. American Technical Support: 800−282−9855 Toll FreeUSA/Canada

Europe, Middle East and Africa Technical Support:Phone: 421 33 790 2910

Japan Customer Focus CenterPhone: 81−3−5817−1050

www.onsemi.com

LITERATURE FULFILLMENT:Literature Distribution Center for ON Semiconductor19521 E. 32nd Pkwy, Aurora, Colorado 80011 USAPhone: 303−675−2175 or 800−344−3860 Toll Free USA/CanadaFax: 303−675−2176 or 800−344−3867 Toll Free USA/CanadaEmail: [email protected]

ON Semiconductor Website: www.onsemi.com

Order Literature: http://www.onsemi.com/orderlit

For additional information, please contact your localSales Representative

© Semiconductor Components Industries, LLC