2019 EPIC: Dual Flying-Capacitor Active Neutral-Point-Clamped (ANPC) Multilevel Inverter

Dual Flying-Capacitor Active Neutral-Point-Clamped (ANPC) Multilevel Inverter Arash Khoshkbar Sadigh, Penn State University Electric Power Industry Conference Oct. 2018 1

Power Electronics Lab

Outline:  Background of Multilevel Inverter

 Conventional Active Neutral Point Clamp

(ANPC) Converter  Proposed Dual Flying Capacitor Multilevel

Inverter  Simulation Results  Experimental Results

 Conclusion

2

Power Electronics Lab

Introduction of Multilevel Inverters:  What is Multilevel Inverter?  Why Multilevel Inverter?

Vout

 Why not Two-Level Inverters?

E/2

 IGBT voltage rating Sa  EMI issue S

-E/2

a

Vout Safilter size  Output

EE/2

 E/4Switching loss Sa E

-E/4

E EE/2

VCE VCE1

Sa

E/2

3.3kV motor-E/2 drive

DC Link Voltage: 3.3kV*1.414=4.7kV

6.6kV motor drive

DC Link Voltage: 6.6kV*1.414=9.3kV VCE2

Sa

3

Use 6.5kV IGBT No IGBT exist Power Electronics Lab

Outline:  Background of Multilevel Inverter

 Conventional Active Neutral Point Clamp

(ANPC) Converter  Proposed Dual Flying Capacitor Multilevel

Inverter  Simulation Results  Experimental Results

 Conclusion

4

Power Electronics Lab

Conventional Active Neutral Point Clamp (ANPC) Converter:

ABB production: ACS2000, 250 – 3200 kW, 4.0 – 6.9 kV

Ref: ABB Brochure of ACS2000 5

Power Electronics Lab

Conventional Active Neutral Point Clamp (ANPC) Converter: LF IGBTs Pros:

HF IGBTs

One flying capacitor 2E E

Vdc

VA

0 -E -2E

:

Cons

Transient voltage imbalance Poor loss distribution

6

Power Electronics Lab

Outline:  Background of Multilevel Inverter

 Conventional Active Neutral Point Clamp

(ANPC) Converter  Proposed Dual Flying Capacitor Multilevel

Inverter  Simulation Results  Experimental Results

 Conclusion

7

Power Electronics Lab

Proposed Dual Flying Capacitor Multilevel Inverter: High Freq.

S1

+ -

E

S2 C1

+

S5 + E

Sʹ1

Vdc S3

+ E

+

Sʹ4

E

-

Sʹ3

2E

Sʹ2

E

iA Sʹ1 VA

Vdc

S6 +

S3

-

S4

VN

-E

S6 C2

+

S50 -2E

E

S4 C2

Line Freq.

S2 C1

Sʹ2

E

-

S1

+

E

iA V iB A V iC B VC

Sʹ4

E

-

Sʹ3

8

Power Electronics Lab

Dual Flying Capacitor Multilevel Inverter: Soft Commutation for proposed DFC-ANPC Converter Off switches

On switches

Off Off switches switches

State 0P

+2E +2E

SS22

S2S22

C C22

C2 -2E -2E

+2E +2E

S2

S3

C1

Sʹ Sʹ22

C11

SS33 SS66

Sʹ4

-2E

S66

VA

S2

SS33

0

S6

S4Sʹ44

C2

Sʹ33

Sʹ4

-2E

Sʹ2SS55 Sʹ1

S5 V VAA

SS66

C22

Sʹ3

Sʹ3

SS22

VAA 0

44

C2

S1

Sʹ Sʹ11

S5

S3S C22

SS11

C1 Sʹ Sʹ22

S55

S33

0

S6

Sʹ Sʹ33

Sʹ22

Sʹ1

SS44

Sʹ Sʹ44

C11

Sʹ11

VA

State 0N +2E+2E

Sʹ2

SS55 V VAA 0

S4

State 0N

State 00

S1S11

Sʹ1

Outbound current

State 00

State State 0P 0P

S115 Sʹ Sʹ

Outbound current

Inbound current

SS11

Sʹ2 00

On switches

S1 C C11

C1

Inbound current

SS44

S3

Sʹ Sʹ44

S4

Sʹ Sʹ33

Sʹ4

S6

Sʹ3

-2E

-2E 9

Power Electronics Lab

Dual Flying Capacitor Multilevel Inverter: High Freq.

Pros:

S1

+ E

-

S2 C1

+

S聞2

E

-

S聞1

+

S3

S5

Vdc S6

E

VN

S4 C2

+

ZVS for line freq. switches No transient voltage imbalance Better loss distribution

Line Freq.

iA V iB A V iC B VC

:

Cons

S聞4

One additional capacitor (but 1.4 times less rms current)

E

-

S聞3

10

Power Electronics Lab

Dual Flying Capacitor Multilevel Inverter: Sinusoidal Reference PSC for S 2

1

PSC for S 4

-1

M

PSC for S 1

0

Natural Balancing Active Balancing

PSC for S 3

S5 1

0 1

PWM 0 Modulation 1 0 1 0 1 0 1 0

VC1

S1

ix

S 2Cycle

Separation

S3

VC2

S4

Cycle change signal

ix S5

Active State Balancing Machine Algorithm Decoder

S1

Active State Balancing Machine Algorithm Decoder

S3

S2

S4 S6

S6 Overlap providing state 00 for soft cycle commutation

2E E 0

Phase shifted modulation.

-E -2E

11

Power Electronics Lab

Outline:  Background of Multilevel Inverter

 Conventional Active Neutral Point Clamp

(ANPC) Converter  Proposed Dual Flying Capacitor Multilevel

Inverter  Simulation Results

 Experimental Results  Conclusion

13

Power Electronics Lab

Simulation Results: VA

I V Simulation and Experiment Parameters 16 A

Circuit Parameter

0

0

Value

0

16 kV

-400

-16 Experiment DC-link Voltage ) VCA1 V VCB1 VCB2 (VVdc CC1 CA2

VB

IB

4.4 DC-link Capacitors (Cdc400 ) 4.2

Flying Capacitors (Cxx)200 4.0

4 0

0

3.8 Modulation Index Phase -200 (M)

-4

3.6

-8

1.6 mF

8

400 µF

0

1

-8

-400

Phase Fundamental Frequency -16 (fo) 10 I C

0

VC

20 Time (ms)

VCA

Voltage (kV)

Phase Switching Frequency (f s) 16 400

8

400 V

VCC2

VBC

16 Voltage (kV)

Voltage (kV)

8

Voltage (kV)

8

-200 Simulation DC-link Voltage (Vdc)-8

-4 -8

50 Hz

30

40

1.65 kHz

8 Load Inductance (Lload200 ) Flying Capacitors’ 0 0Voltages Load Resistance (Rload-200 )

Current (A)

Voltage (kV)

Voltage (kV)

200

4

Current (A)

400

Current (A)

Voltage (kV)

8

AB

4 0 -4 -8 0

10

30

40

0

Balance Booster Capacitance (Cboost)

Balance Booster Resistance (R boost) Phase Voltages & Currents

14

18 Ω

-8

-400 Balance Booster Inductance (Lboost -16 )

20 Time (ms)

15 mH

1.85 mH 10

20 Time (ms)

30

40

20 µF

1.5 Ω Line Voltages Power Electronics Lab

Experimental Results: Reconfigurable Multilevel Converter Platform IGBT Module

Control Unit

Diode Module

dc-link

Phase legs

Measurement Panel

Converter Platform

15

Power Electronics Lab

Experimental Results: Reconfigurable Multilevel Converter Platform Converter Platform

Measurement Devices

Power Supply

Inductor Bank

Back

Resistor Bank

Front

16

Balance Booster

Power Electronics Lab

Experimental Results:

Phase Voltages (100V/div) and Currents (5A/div) SteadyFlying stateLine Capacitors’ flying Voltages Capacitors’ Voltages (100V/div) Voltages (20V/div) (5V/div)

17

Power Electronics Lab

Experimental Results: M = 0.4

Conventional ANPC

M = 0.95

T max= 100째C

T max= 81.5째C

T max= 68.0째C

Proposed DFC-ANPC

T max= 95.5째C

18

Power Electronics Lab

Outline:  Background of Multilevel Inverter

 Conventional Active Neutral Point Clamp

(ANPC) Converter  Proposed Dual Flying Capacitor Multilevel

Inverter  Simulation Results  Experimental Results

 Conclusion

19

Power Electronics Lab

Conclusion:  Application of proposed New multilevel inverter ismultilevel proposedinverter:  Medium Extrafor flying capacitor voltage motor drive  ZVS line frequency switches. times less rms  Medium voltage grid current tied inverterfor line frequency No 1.4 transient voltage imbalance

 switches.

Solid state transformer  Easier to be extended for higher number of levels.

 Better power loss distribution.  Lower junction temperature.  Can provide more power with same switches.

20

Power Electronics Lab

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Power Electronics Lab