DC Microgridsand Distribution Systems for microgrid- Buck chopper DC +170 V 3φ200 V 1φ100 V DC 48

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Transcript of DC Microgridsand Distribution Systems for microgrid- Buck chopper DC +170 V 3φ200 V 1φ100 V DC 48

  • Ise Laboratory, Osaka Univ.

    DC Microgrids and Distribution

    Systems for Residences

    Toshifumi ISE,

    Hiroaki KAKIGANO

    Osaka University, JAPAN

  • Ise Laboratory, Osaka Univ.

    Outline of the Presentation

    1. Introduction

    2. System Configuration and Control Scheme

    3. System Configuration for Loss Calculation

    4. Data for Loss Calculation

    5. Results of Loss Calculation

    6. Conclusions

    2

  • Ise Laboratory, Osaka Univ. 3

    1. Introduction

  • Ise Laboratory, Osaka Univ.

    Low Voltage Bipolar Type DC Microgrid

    4

    AC

    DC

    Supervisor

    computer

    Supervisor

    computer

    Secondary

    battery

    Secondary

    battery

    Electric double

    layer capacitor

    (EDLC)

    Electric double

    layer capacitor

    (EDLC)

    6.6 kV / 200 V

    Bidirectional

    rectifier

    Bidirectional

    rectifier

    PV systemPV system

    DCDC

    Signal line

    (Wireless network can

    substitute for it.)

    3 phase

    inverter

    3 phase

    inverter

    Single phase

    inverter

    Single phase

    inverter

    Buck

    chopper

    Buck

    chopper

    DC +170 V3200 V

    1100 V

    DC 48 V

    Local Controller

    Magnetic

    contactor +

    Islanding

    protector

    Magnetic

    contactor +

    Islanding

    protector

    1100 V

    DC

    DC

    DC

    DC

    DC -170 V

    Utility grid

    Line resistances

    and inductances

    GG

    Gas engine

    cogeneration

    system

    (GC)

    Gas engine

    cogeneration

    system

    (GC)DC

    AC

    Voltage

    balancer

    Voltage

    balancer

    Single phase

    inverter

    Single phase

    inverter

  • Ise Laboratory, Osaka Univ.

    Features of Proposed DC Microgrid

    1. The distribution of load side converters

    provides super high quality power supplying.

    2. Various forms of electric power like single

    phase 100 V, three phase 200 V, DC 100 V

    can be obtained from the 170 V DC line.

    3. Rapid disconnection and reconnection with

    the utility grid are realized easily.

    4. Electric power can be shared between load

    side converters.

  • Ise Laboratory, Osaka Univ. 6

    2. System Configuration

    and Control Scheme

  • Ise Laboratory, Osaka Univ.

    System Configuration

    All residences have their own distributed generations

    and share each others electrical power.

    Concept of the System

    INV

    AC Residence

    Utirity Grid

    Energy storage

    Control System

    distribution linein a building

    Gas Engine

    AC DCDC Electric Power Sharing

    Gas Engine

    Gas Engine

    INV INV

    AC AC

    Electric Power Sharing

    Residence Residence

    HotWater

    HotWater

    HotWater

    AC

    DC

    DC

    DC

    DC Microgrid for Residential Complex

    All cogenerations are controlled by on/off operation.

    Then, total power from the generations can be

    calculated by a number of operating generations.

  • Ise Laboratory, Osaka Univ.

    Power Management Scheme : Interconnected Mode

    ACDC

    Utility grid

    Load

    DG

    Load

    DGDC

    DCElectric Double

    Layer Capacitor

    (EDLC)

    Time

    Power

    Load Curve

    Output of DG

    Power through

    Rectifier

    Interconnected operation mode

    DC voltage control

  • Ise Laboratory, Osaka Univ.

    ACDC

    Load

    DG

    Load

    DGDC

    DC

    Discharging

    Super Capacitor

    Load Curve

    Output of DGTime

    Power

    Charging

    Super Capacitor

    Islanding operation mode

    Power Management Scheme: Islanding Mode

    Utility grid

    EDLC

    DC voltage control

  • Ise Laboratory, Osaka Univ.

    Configuration of Experimental System

    The experimental system

    consists of 3 houses.

    EDLC was chosen as an

    energy storage.

    Rectifier

    DCCB

    G

    GE

    ///

    INV

    /

    AC

    LOAD

    DCCB

    DC

    Power

    Supply

    DCCB

    Gas Engine

    Simulated

    Source

    DC/DC

    Gas Engine

    Cogeneration

    DC/DC DC/DC

    AC100V

    DC/DC

    EDLC

    ~

    AC 200 V

    ///

    Voltage

    Balancer

    DC

    Power

    Supply

    Gas Engine

    Simulated

    Source

  • Ise Laboratory, Osaka Univ.

    Rectifier

    Inverter

    Control Boads

    DC Circuit Breakers

    DC/DC Converters

    Hot Water Tank

    Gas Engine Unit

    EDLC

    ( Rated Capacity 1 kW)

    Gas engine cogeneration

    System setup

    Appearance of the System

  • Ise Laboratory, Osaka Univ.

    Voltage clamping control is mentioned.

    The experimental results are shown.

    Fundamental system characteristics

    Load variationOperation of DGs

    Voltage sagShort Circuit at the load side

    Power Supplying to real home appliances

    Control method of operating DGs amount

    Disconnection from and reconnection with the utility grid

    System stable operation was confirmed by the experiments as follows:

    In this presentation

    Experiments

  • Ise Laboratory, Osaka Univ.

    Control of EDLC in Interconnected Mode

    ACDC

    Utility grid

    Load

    DG

    Load

    DGDC

    DC

    Interconnected mode

    Electric

    Double Layer

    Capacitor

    (EDLC)

    DC Voltage Constant Control

    Upper Limit380 VLower Limit320 V

    Clamp distribution voltage when

    the voltage becomes out of range.

    Distribution Voltage 340 V 170 V

    3. Help disconnection and reconnection process

    Effect of Voltage Clamp

    2. Prevent over voltage of the devices connected to dc line

    1. Keep distribution voltage if the current of rectifier is limited.

  • Ise Laboratory, Osaka Univ.

    Control Scheme of Disconnection

    Rectifier

    DCCB

    G

    GE

    ///

    INV

    /

    AC

    LOAD

    DCCB

    DC

    Power

    Supply

    DCCB

    0.7 kW

    Gas Engine

    Simulated

    Source

    DC/DC

    Gas Engine

    Cogeneration

    DC/DC DC/DC

    AC100V

    DC/DC

    EDLC

    ~

    AC 200 V

    ///

    0 kW1 kW

    0 kW0 kW

    STOP !

    1. Stop rectifier when problem is detected

    2. Start clamp control of EDLC converter

    CLAMP !

    3. Change to constant voltage control

    Voltage Control

    Voltage

    Balancer

    DC

    Power

    Supply

    Gas Engine

    Simulated

    Source

    0 kW

  • Ise Laboratory, Osaka Univ.

    Experimental Results of Disconnection

    Seamless disconnection was verified when blackout occurred.

  • Ise Laboratory, Osaka Univ.

    Control Scheme of Reconnection

    Rectifier

    DCCB

    G

    GE

    ///

    INV

    /

    AC

    LOAD

    DCCB DCCB

    0.7 kW

    DC/DC DC/DC DC/DC

    AC100V

    DC/DC

    EDLCVoltage

    Balancer

    ~

    AC 200 V

    ///

    0 kW1 kW

    0 kW

    START!

    1. Detect the voltage of utility grid

    2. Change EDLC to clamp control

    3. Start voltage control of rectifier

    CLAMPVoltage Control

    Gas Engine

    Cogeneration

    DC

    Power

    Supply

    Gas Engine

    Simulated

    Source

    0 kW

    DC

    Power

    Supply

    Gas Engine

    Simulated

    Source

    0 kW

  • Ise Laboratory, Osaka Univ.

    Experimental Results of Reconnection

    Smooth reconnection was verified when utility grid was recovered.

  • Ise Laboratory, Osaka Univ.

    REC

    G

    GE

    ///

    INV

    /

    AC

    LOAD

    DC

    Power

    Source

    DC/DC

    Gas engine

    DC/DC DC/DC

    1 100 V

    Analyzing

    Power

    Supply

    ///

    DC

    Power

    Source

    1 kW

    1 kW 1 kW

    0.7 kW 1 kW

    0.7 kW

    House 1 House 2 House 3

    Voltage sag of the utility grid

    (200 V 100 V (-50 %, 0.5 s) 200 V)

    0 kW

    DC/DC

    EDLC

    Experiment of Voltage Sag

  • Ise Laboratory, Osaka Univ.

    The voltage sag did not make

    the system disconnect.

    Fault ride-through operation

    Experimental Results of Voltage Sag

  • Ise Laboratory, Osaka Univ. 20

    3. System Configuration

    for Loss Calculation

  • Ise Laboratory, Osaka Univ. 21

    Objective of this Research

    Loss comparison between ac Loss comparison between ac microgridmicrogrid and dc and dc microgridmicrogrid

    Losses were calculated by

    Load data measured in a

    residential complex

    PV output data estimated by

    global solar radiation and

    temperature of a PVpanel

    measured by Osaka University.

    Those are whole year data

  • Ise Laboratory, Osaka Univ.

    Size of Target Residential Complex

    22

    4 floors

    5 houses on a floor

    Size is referred to a real residential complex in Japan

    20 houses

    PV : 30 kW

    Gas

    Engine

    6.6 kW

  • Ise Laboratory, Osaka Univ.

    Distribution Line Configuration (AC)

    23

    PV 30 kW

    GE 6.6 kW

    Single-Phase

    AC 200 V

  • Ise Laboratory, Osaka Univ.

    Distribution Line Configuration (DC)

    24

    PV 30 kW

    GE 6.6 kW

    DC 200 V

  • Ise Laboratory, Osaka Univ.

    Composition of Each House (AC)

    25

    Air conditioner

    refrigerat