Converter Topologies for Smart-grid Applications

Converter Topologies for Smart-grid Applications

Santanu K. MishraMinistry of Labor and Entrepreneurship

Chair Professor

Department of Electrical EngineeringIndian Institute of Technology Kanpur

Email: [email protected]

Power Management LabIIT Kanpur, 11th May, 2019

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Professional Experience1. Ph.D. in 2006 from University of Florida, Gainesville

(Power Management IC)

2. 2004‐2008: Staff Application Engineer at International Rectifier Corporation, North Kingstown, Rhode Island (Server Power Supply)

3. Present: Professor at Indian Institute of Technology, Kanpur

4. Fall 2017: Visiting Professor at CPES, Virginia Tech., Blacksburg

5. Consultant: General Electric Global Research, BangaloreHindustan Aeronautics Ltd.Maruti‐Suzuki Ltd.


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(a) Introduction

(b) Fundamental Differences:

High Power Vs low power

(c) Switch Selection in Different Applications

(d) Magnetic Design in Different Applications

Sub-topic Overview


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Introduction

Block Diagram

Power StageProcesses Power

between source and loadControl

Helps in Regulation and Control

Classification


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Why Discuss High Power Vs Low power

Power Converter

Power Converter

Converter Technologies are different

Generated Power Has to be Transmitted to Load Centers

Generated Power to be used right away


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Converter Power Rating

11 kV 100 kVA

I≈5 A

0.44 kV 100 kVA

Is=130 A

Inverter(DC to AC)

500 VDC10 kVA

I≈20 A

440 V/3 ph10 kVA AC

I≈13 A

Increase in current leads to power loss in Switch

Easier to implement 10 kVA Power Converter at 500 V than at 50 V


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Switch Options

48 V10 kVA

I≈208 A

440 V/3 ph10 kVA

I≈13 A

Sw. Frequency

Pow

er

100s kHz, Mosfets (Rooftop PV)o

> 1000 Hz, IGBT, SiC (UPS, Solar PV)o

< 500 Hz, Line Commutation (HVDC) o

1-3 MHz, GaN (Consumer Electronics)o

Theory of the Game - Switch Choice- Magnetic Design

Inverter(DC to AC)


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HVDC: ApplicationRihand-Dadri HVDC

1500 MW, ±500 V

If Efficiency is 99 %Loss=15.15 MWSwitches have to take it!!

If Efficiency is 99.99 %Loss=0.15 MWMore Reasonable!!

Failure not an option as - Mission critical- Huge lead time for spares


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HVDC: Topology of choice

Pulse Rectifiers…Line Commutation Preferred


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Datacenter UPS

IGBT Based Design with Frequency at 1-5 kHz

Mitsubishi 225 KVA UPSMitsubishi 225 KVA UPS


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Magnetic Core ComparisonMaterial Permeability Resistivity Sat. Flux

densityTypical

Frequency Usage

CRGO (Si –Steel)(Si 3.1 %)

2k-35k 48µ Ω-cm 2 T 50 Hz

Amorphous(66% Co 15% Si

4% Fe)

2000 100-150µ Ω-cm 0.5-0.65 T In kHz

Nano-crystalline(FeCuNbSiB)

20K-200K 115µ Ω-cm 1.23-1.45 T In kHz

Ferrite (MnZn) 1.5k-15k 400-600 Ω-cm 0.5 T 100s of kHzFerrite (NiZn) 80 107 Ω-cm 0.3 T Multi MHz

Frequency Increase


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Impact of High Sw. Frequency

50 Hz Vs 20 kHzTransformer

100 kHz Vs 1 MHzTransformer


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Case Study of an EV Charger Design


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EVs around the worldMake BATTERY RANGE ON-BOARD

CHARGER CAPACITYMILES ADDED

PER HOURNISSAN LEAF-

201730 KWH/360 V 107 MI 6.6 KW 23.4

FORD FOCUSELECTRIC

33.5 KWH/325 V 115 MI 6.6 KW 22.8

CHEVY BOLT 60 KWH/350 V 238 MI 7.2 KW 28.2KIA SOULELECTRIC

27KWH/360 V 93 MI 6.6KW 22.8

FIAT 500E 24 KWH/364 V 87 MI 6.6 KW 24.0MITSUBISHI I

MIEV16 KWH/330 V 62 MI 3.3 KW/6.6 KW 12.6/25.8

BMWI3 33 KWH/360 V 124 MI 7.4 KW 27.6TESLA MODEL

S100 KWH/400 V 289 MI 17.3 KW 49.8

TESLA MODEL 3 75 KWH/350 V 310 MI 11.3 KW 46.8


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EV Charger

DC charger: Charges the Battery directly

AC Charger: uses On-board Power electronics tocharger battery


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EV Charger Standards

Standards take care of connections andcommunications between EV and source

Standard/Plug connectors

Charging Specs for corresponding standards(as of 2016 installations)

Communication Protocol

Compatible Manufactures

CHAdeMo(Charge de Move)

62.5 kW DC Fast Charging CAN Nissan, Mitsubishi, Toyota

SAE-J1772-2009(SAE: Society of

Automotive Engineers)

Level 1 and Level 2Supports AC charging:110 V/240 V @ 19.2 kW

Power LineCommunication

(PLC)

GM, Ford, Nissan, Tesla

SAE-Combined Charging System

(CCS)

AC Level 1 or Level 2+ DC Fast Charging: AC: up to

19.2 kWDC: up to 90 kW

Power LineCommunication

(PLC)

Volkswagen, GM, BMW

GB/T AC: Level 1 and Level 2250 V / 16 A or 32 A

DC: 220-470 V, 125 A

CAN Chinese manufacturers


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EV Chargers

- Monitoring Power flow- Monitoring Power flow- Safety monitoring

AC Charging has lower rating as they use on-board charger

- AC-DC Off board conversion- Monitoring Power flow- Monitoring Power flow- Safety monitoring


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On-Board Charger

Circuit View

Package View


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DC Fast Charger


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A Practical EV Charger: Design Philosophy

• Input to the charger is coming from two sources of energy namely, AC Grid and Solar Photovoltaic.

• After rectification of AC voltage, it is fed to the dc link capacitor. Similarly, the photovoltaic also fed to this capacitor after the dc-dc conversion stage.

• The third stage is isolated dc-dc conversion, after that the power is directly fed to the battery of E-Rickshaw.


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Topologies for Isolated DC-DC Converters

Fly-back Converter

Full Bridge Converter Dual Half-Bridge Converter

Dual Active Bridge Converter


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Dual Active Bridge Converter(Overview)

• Distinct Features : Galvanic isolation Much simpler control Zero voltage switching(ZVS), without additional circuitry Additional inductor is not required High power and high efficiency operation


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3D Design of the Isolated DC-DC converter


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Physical dimensions of isolated dc-dc stage of the charger

Load connection

Bias Card for Gate Drivers

Input DC link

connection


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Steady State Waveforms at Llk = 22 𝞵H

VABVCD

VDS7

RL = 6 ohm

Vdc = 310 V

D = 0.1 D = 0.5

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Efficiency & Output Power Curves at Llk = 22 𝞵H

Maximum efficiency is 95 % at power output of 766 W.


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D = 0.1

Steady State Waveforms at Llk = 9 𝞵H

VABVCD

VDS7

Vdc = 330 V


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ThankYou !!

Documents

Converter Topologies for Smart-grid Applications