“emi mitigation and containment in sic-based modular ups ... · december 8 2015 annual meeting...

Center for Power Electronics SystemsThe Bradley Department of Electrical and Computer Engineering

College of EngineeringVirginia Tech

Blacksburg, Virginia, USA

“EMI Mitigation and Containment in SiC-Based Modular UPS for

Commercial Applications”

Presented by:

Rolando Burgos

CPES-Consortium

WBGHPCS

CPES-Consortium

HDI

College ofEngineering

December 8 2015

Annual Meeting

“EMI Mitigation and Containment in SiC-Based Modular UPS for

Commercial Applications”

Rolando Burgos, Dushan Boroyevich

Center for Power Electronics Systems (CPES)Virginia Tech

January 17-19-2017March 2, 2017 Center for Power Electronics Systems 2

Commercial UPS System

Decentralized power architecture (DPA)

• Each module operates as standalone UPS unit

• Module features:–Rectifier, inverter, bypass switch

–Back-feed protection–Control logic–Displays & monitoring

Fault tolerant UPS design free of single points of failure

ABB Conceptpower DPA 500, 480 V, UL, 100 kW to 3 MW, modular UPS.

March 2, 2017 Center for Power Electronics Systems 3

Project Objectives

Objectives1. Mitigation and containment strategy for

EMI noise generated in SiC-based UPS power modules.

2. Compliance of applicable EMI standards and reliable operation of 100 kW SiC-based UPS module.

Why SiC?SiC will boost efficiency and help improve

power density of UPS

Key approachUse of impedance-based EMI noise

channeling to divert it from critical control pathsMinimize EMI noise generation within UPS

module SiC dv/dt > 50 V/ns, di/dt > 10 A/ns


EMI Emissions in SiC Converters


UPS Module Architecture

• Grid-interface active front-end (AFE) converter• DC-DC battery charger• Sine-wave voltage-source inverter (VSI)

480V Grid AC Load

UPS Module

With SiC,

Smaller Passives! 800


Barrier to CommercializationInternal EMI propagation path EMI Standard

IEC62040


Topology Selection

• Three-level is superior to two-level counterpart–Inherently lower voltage steps (Vdc/2) and common-mode (CM) voltage generation

–Greater freedom to mitigate CM voltage generation–Higher efficiency at higher switching frequencies

Frequency [MHz]100 101

-50

-40

-30

-20

-10

0

10

20

30

40

50Comparison of CM Noise spectrum W/ fsw = 100kHz

2-level3-level

SVPWM

6 dB reductionSVPWM

SVPWM

OOO POO PNNNOONPP

OONOPONPO PON

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP


Topology Selection

2-Level MICROSEMI : 1.2 kV 42 A HB Module ( 49 Ω) CREE : 1.2 kV 59 A 6-pack Module ( 30 Ω)

3-Level NPCMICROSEMI : 1.2 kV 40 A NPCModule ( 49 Ω)

3-Level T-typeMICROSEMI : 1.2 kV 42 A HB Module+ 700 V 41 A Discrete MOSFET x 2

95.50%96.00%96.50%97.00%97.50%98.00%98.50%99.00%

10 60 110Switching Frequency [kHz]

Converter Efficiency at Tjunc = 502‐LEVEL CREE 6‐Pack NPC T‐type


Battery Charger Topology

• Bi-directional dc-dc converter features:– CM voltage noise generation– Efficiency– Battery filter size– Neutral point balancing

Buck Three-Level Buck NPC PEBB-based Converter


EMI Impact of Battery Charger


?

AC-AC Converter CM Voltage Emissions

Requires formulation of three-port CM circuit model of UPS module

CM Circuit Model Derivation

Ground ofMain Grid Phase Output

to Heat Sink

DC-Bus to Heat Sink

Battery Cabinet to Earth Ground

Ground Impedance

Phase Output to Heat Sink


CM Circuit of UPS Module

CM ac-to-ac stage

CM dc-to-dc stage


Predicted EMI Noise Generation

Frequency [MHz]100 101

-100

-80

-60

-40

-20

0

20Comparison of CM Noise spectrum

BuckThree-level Buck (180deg)Three-level Buck (0deg)

~10 dB difference

Buck Converter

Three-Level Buck ConverterMarch 2, 2017 Center for Power Electronics Systems 14

Single CM-Pulse SVM with Neutral Point Balancing Capability

LMZ: Large + Medium + Zero vector sequenceMMS: Medium + Medium + Small vector sequence

LMZ( /6,0,0)

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON

MMS(0,0, /6)

MMS2(0,0, /6)

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON


CM Voltage Evaluation

time [ms]0 5 10 15

-500

0

500SVPWM @ Fsw = 30kHz

time [ms]6.68 6.7 6.72 6.74 6.76

-500

0

500

time [ms]0 5 10 15

-500

0

500CMVR PWM @ Fsw = 30kHz

time [ms]6.68 6.7 6.72 6.74 6.76

-500

0

500Frequency [MHz]

100 101-60

-50

-40

-30

-20

-10

0

10

20

30Comparison of CM Noise spectrum: According to PWM

SV PWMSCMVP PWM


Neutral-Point Voltage Balance

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON

OOO POO PNNNOONPP

OONOPONPO

NPN OPN PPN

ONOOOPNOP PNO

NNP ONP PNP

PON

dVdc = VdcH-VdcL

PWM_Type

Sa, Sb, Sc

Common-Mode Voltage

-100

-50

0

0

1

2

0

0

0

× 1e-20.0 0.5 1.0 1.5 2.0 2.5 3.0

-200

0

200

I II

MMS

LMZ

MMS2


Gate-Driver with High dv/dt Immunity


Impedance-based Channeling of EMI Noise in WBG Converters

• Successfully applied to gate-drivers for SiC and GaN devices

• Power circuit presents low impedance path to EMI noise

GaN-based Three-phase VSI

106

107-10

0

10

20

30

40

50

60

Frequency (Hz)

dBuA

Blue: Gate driver logic path; Green: Gate drive power path; Red: power circuit


Digital Control Platform

Control Board• High computing power:

TI28377D + FPGA

Sensor + ADC board• Measures at high

di/dt and high dv/dt• SPI communication

with control board

Gate driver board• High dv/dt immunity

(> 50 V/ns)

Optical IO interface• Gate signals • SPI Communication

with ADC board


Next Steps


• Power Stage Construction Testing– Gate-driver testing and SiC module double-pulse test– Busbar construction– Inverter-rectifier operation testing– Battery charger converter testing

• Controller Testing– Sensor + ADC board population– Test for SPI communication between main FPGA & multiple sensors

• Measurement of EMI emissions and design of input and output EMI filters

Project Team


Sungjae OhnPhD student

Paul RankinWBGen FellowMS student

Jianghui YuPhD student

Eric GiewontURS, Junior Year

John NoonURS, Junior Year

“emi mitigation and containment in sic-based modular ups ... · december 8 2015 annual meeting...

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