Autonomous Distributed V2G (Vehicle-to-Grid) Satisfying Scheduled Charging

Authors: H. Taniguchi, T. Nakajima, K.M. Liyanage, J. Baba

Presenter: Jian Qiao

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Outline

Introduction

V2G Control Scheme

Power Grid Model

V2G Model

Simulation Results

Battery Model

Conclusion

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Introduction

1. Smart grid strategies are expected to utilize distributed generations and controllable loads in the demand side.

2. Integration of EV and PHV brings potential of V2G.

3. Supply and demand dispatch reduces the cost.

4. Propose autonomous distributed V2G control scheme providing spinning reserve for intermittency of RESs.

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V2G Control Scheme (1)

1.Supply and demand imbalance can be observed from frequency deviation;2. V2G power is controlled with droop characteristics against the frequency deviation.

Traditional Charging

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Smart Charging

V2G Control Scheme (2)

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Power Grid Model

1. 50 Hz system2. two interconnected power grid

One V2G pool includes 20 000 vehicles

Two V2G pools in grid A , one with largesize battery (EV1) and the other with middle size battery (EV2);

Grid B has one V2G pool including PHVs with small size battery.

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Battery Model

• Simplified battery model: voltage source including open circuit voltage

(OCV) and internal resistance (Rint)

• Necessary energy from the present SOC (SOCi) to the destination

SOC (SOCd) is calculated by integrating the OCV as follows:

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• Closed Circuit Voltage and V2G power

Battery Model

• SOC is updated as

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Simulation Results (1)

EV1 is plugged in grid A at 2h with initial SOC as 20%, then scheduled to be plugged out with destination SOC as 90% after 8hours. EV2 and PHV work as V2G pool maintaining 50% SOC during the simulation.

Frequency deviation for grid A and grid B.

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V2G power output of EV1, EV2 and PHV

Simulation Results (2)

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Battery SOC of EV1, EV2 and PHV

Simulation Results (3)

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• Effective for distributed spinning reserve without system wide information exchange;

• Proposed smart charging control scheme satisfies the schedule charging by the vehicle users.

Conclusions