a study on emi noise reduction in boost-type pfc circuit · a study on emi noise reduction in...

A Study on EMI Noise Reduction

in Boost-Type PFC Circuit

Noriyuki Oiwa, Shotaro Sakurai, Nobukazu Tsukiji,

Yasunori Kobori, Haruo Kobayashi

Division of Electronics and Informatics

Gunma University

IPS03 Analog and Power

April 28, 2018 (Wed)

Gunma Univ. Kobayashi Lab

Outline

• Background and Purpose

• Conventional PFC Power Supply

• Proposed PFC Power Supply

－Using frequency modulation

• Diode recovery current reduction

• Conclusion

2/31

Outline






• Conclusion

3/31

What is Power Supply Circuit ?

• Commercial power supply circuits

➞ Convert AC into DC voltages

4

AC-DC

Output Voltage

(ex. DC 300V)Input Voltage

(50/60Hz 100V)

DC-DC

Power Supply

4/31

Research Purpose

AC-DC converter improvement

● EMI noise reduction in PFC circuit

➞Using noise spectrum spread

with frequency modulation

● Efficiency improvement in high speed operation

➞ Diode recovery current reduction

with SiC SBD

PFC: Power Factor Correction

SBD: Schottky Barrier Diode5/31

EMI Noise

● EMI noise generation by current flow

● Large scale analog filter for EMI noise removal

EMI: Electro-Magnetic Interference

Radiation noise

Conduction noise

6/31

Am

plit

ud

e

Frequency Frequency

Am

plit

ud

e

Noise Spectrum Spread

• Reducing peaks of higher harmonics

of clock frequency

➝ Spreading noise energy

by frequency modulation

Without spreading With spreading 7/31

Problem (High Speed Clock)

Clock frequency increase

Fast response, Small L, C

Large noise, energy loss

Low clock freq.

High clock freq.

8/31

[t]

[t]

Vo

lta

ge[v

]V

olt

age

[v]

Outline






• Conclusion

9/31

L

C

C

Role of PFC Circuit

PFC shapes input current waveform

Without PFC With PFC

10/31

PFC Operation

PFC Circuit

Input current, input voltage: same waveforms

➞ Harmonics reduction

➞ Loss reduction

PFC＝Effective power

Apparent 𝑝𝑜𝑤𝑒𝑟＝

ሶV ሶIdt

തVതI

PFC: Power Factor Correction

Apparent 𝑝𝑜𝑤𝑒𝑟

Active 𝑝𝑜𝑤𝑒𝑟 eactive 𝑝𝑜𝑤𝑒𝑟

Active 𝑝𝑜𝑤𝑒𝑟 (↑) eactive 𝑝𝑜𝑤𝑒𝑟(↓)

Apparent 𝑝𝑜𝑤𝑒𝑟(=)11/31

Conventional PFC Circuit

EMIFilter

FixedFrequency

IntegrationCircuit

Error Amp1

Comp1Error Amp2

Gatedriver

C

L

Boost Converter

PFC

12/31

Outline




－ Using frequency modulation


Conclusion

13/31

EMIFilter

FMClock

Error Amp1

Error Amp2

Comp1

Gatedriver

IntegrationCircuit

C

L

Proposed PFC Circuit

14/31

Frequency Modulation

• Frequency modulation fluctuates

clock freq. linearly by time

➞ Clock noise spectrum is spread

[V]

[V]

[t]

[t]

VCO: Voltage Controlled Oscillator

VCO

Triangle wave

Modulation clock

15/31

PFC Circuit for Simulation

16/31

EMIFilter

Integration Circuit

Clock Signal(100kHz)

AC 100V

50Hz

330μF

2.2mH

=400V

Gatedriver

Error Amp2

Comp1Gatedriver

PWM

ClockSignal

Integration Circuit

Simulation Results of Conventional PFC

Measuring point of

Fourier transform 17/31

PWM spectrum

Frequency/kHertz 100kHertz/div

0 100 200 300 400 500

Spectr

um

(PW

M0)

/ V

1m

10m

100m

1

10

Am

plit

ude[

V]

Frequency[kHz]

9.5V

100kHz point

3.1V

1.0V

(∆f=±10kHz)

(∆f=±1kHz)

9.7dB lower than

using fixed freq.

Simulation Results of Proposed PFC

18/31

PWM spectrum

Am

plitu

de[V

]

Frequency[kHz]


0 100 200 300 400 500

Spectr

um

(PW

M0)

/ V

1m

10m

100m

1

10


0 100 200 300 400 500

Spectr

um

(PW

M0)

/ V

1m

10m

100m

1

10

Simulation Results of Proposed PFC

100kHz point

3.1V

1.0V

(∆f=±10kHz)

(∆f=±1kHz)

19.6dB lower than

using fixed freq.

9.7dB lower than

using fixed freq.

19/31

PWM spectrum

Am

plitu

de[V

]

Frequency[kHz]


0 100 200 300 400 500

Spectr

um

(PW

M0)

/ V

1m

10m

100m

1

10


0 100 200 300 400 500

Spectr

um

(PW

M0)

/ V

1m

10m

100m

1

10

Output Voltage Ripple

• Clock frequency changes

→ Output voltage ripple

does not change much.

200kHz ±1.0kHz100kHz ±1.0kHz

time/mSecs 5mSecs/div

500 505 510 515 520 525 530 535 540

Vo /

V

397

398

399

400

401

402

403

Volt

age[V

]

Time[ms] time/mSecs 5mSecs/div

500 505 510 515 520 525 530 535 540

Vo /

V397

398

399

400

401

402

403

Volt

age[V

]

Time[ms]

20/31

Outline






• Conclusion

21/31

Diode Recovery Current

• Generated at turn off moment

➞ Loss enlarged by clock frequency increase

ON OFFOFF

0

(t)

(t)-

P

P

N

N

Hole

Electron

+

+

-

Forward voltage

Reverse Voltage

22/31

Recovery Current Reduction Approach

• Schottky Barrier Diode(SBD) usage

Breakdown voltage: Si (200V) < SiC (600V)

SiC usage

23/31

Metal

Electron transfer

Semiconductor

Potential[V]

Electron transfer

Metal Semiconductor

Potential[V]

SiC Features

Comparison of SiC with Si

● Pro - High breakdown voltage

- High speed operation

● Con - High cost

Cost of SiC as a part is high.

But a whole system using SiC may become lower.

24/31

Recovery Current Generation Location

EMIFilter

Gatedriver

ClockSignal

Error Amp1

Error Amp2

Comp1

25/31

SBD Simulation Circuit

• Only diode simulation

• Observing a change in voltage, current and

power at the same measurement point

・PN(20ETS12)

・SiC-SBD(SCS206AJHR)

10Ω

DC 20V

SW 500kHz

Measurement point

26/31

Simulation Results

PN

SiC-SBD

27/31

Vd2 /

V-10

-6

-2

Id2 /

A

-40

-10

20

Time/uSecs 200nSecs/div

3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D6)

/ W

-300

0

300

Vd1 /

V

-10

-6

-2

Id1 /

A

-40

-10

20


3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D2)

/ W

-300

0

300

Time[μs]

Time[μs]

106W

-40A

-16A

280W

Vd2 /

V-10

-6

-2

Id2 /

A

-40

-10

20


3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D6)

/ W

-300

0

300

Vd1 /

V

-10

-6

-2

Id1 /

A

-40

-10

20


3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D2)

/ W

-300

0

300

Time[μs]

Time[μs]

106W

-40A

-16A

280W

Recovery Current Comparison

PN

SiC-SBD

Recovery current

reduction by 24A

28/31

Vd2 /

V

-10

-6

-2Id

2 /

A

-40

-10

20


3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D6)

/ W

-300

0

300

Vd1 /

V

-10

-6

-2

Id1 /

A

-40

-10

20


3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4Pow

er(

D2)

/ W

-300

0

300

Time[μs]

Time[μs]

106W

-40A

-16A

280W

Switching Loss Comparison

PN

SiC-SBD

Switching loss

reduction by 37.9 %

29/31

Outline






• Conclusion

30/31

Conclusion

Proposal for PFC power supply in high speed

● PFC with frequency modulation

Fixed frequency ➞ Frequency modulation

EMI noise reduction

● Diode recovery current reduction

SiC-SBD employment

Comparison with switching loss

of PN diodes and SiC-SBD

Efficiency improvement 31/31

質問事項

・リカバリー電流の過渡応答時間は？

→ 次の機会までに調べます。

→Simplisシミュレーション結果

・SiC使用 : 0.2 [ps] ・Si使用 : 1.3 [ps]

33/31

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