Bidirectional EV Charging Station for Contract Demand Reduction
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Solution Overview
Problem
Existing EV charging apparatuses with multiple charging stations face high contract demand prices and increased power system load due to simultaneous charging, which can be costly and strain the power infrastructure.
Innovation Solution
The EV charging apparatus includes multiple charging stations, power supply circuits, a charging/discharging station, and a bidirectional converter that allows for power conversion and storage, enabling the reduction of contract demand by utilizing stored EV power during peak demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple charging stations are installed to simultaneously charge multiple EVs, then charging convenience and productivity are improved, but contract demand cost and power system load increase
Solution Approach 1:
The system performs preliminary charging of EV power storage devices during off-peak hours when power demand is low. The control unit charges the power storage device connected to the charging/discharging station during periods when the number of EVs to be charged is low, so that power can be supplied from the storage battery when power demand is high.
Solution Approach 2:
The EV power storage device acts as an intermediary energy storage medium between the power system and the multiple charging stations. The bidirectional converter enables the power storage device to both charge from and discharge to the power supply circuits, mediating the power flow to reduce contract demand.
2Reliability
If stationary storage battery capacity is increased to ensure sufficient power supply during high demand, then reliability is improved, but initial cost increases
Solution Approach 1:
The system uses the EV's own power storage device to serve the charging apparatus's power needs. The power storage device mounted in the EV connected to the charging/discharging station is utilized to supply power to the power supply circuits when power demand is high, eliminating the need for a separate stationary storage battery.
3Use of energy by stationary object
If stationary storage batteries are installed to reduce contract demand, then contract demand cost is reduced, but device complexity and safety management increase due to hazardous materials
Solution Approach 1:
The EV power storage device acts as an intermediary energy storage medium between the power system and the multiple charging stations. The bidirectional converter enables the power storage device to both charge from and discharge to the power supply circuits, mediating the power flow to reduce contract demand.
Solution Approach 2:
Instead of installing a stationary storage battery, the system copies the power storage function using the EV's existing power storage device. The EV's battery serves the dual purpose of vehicle power storage and charging station energy storage, eliminating the need for separate hazardous material storage infrastructure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces contract demand and power system load by allowing the EV charging apparatus to supply power from the EV's storage during peak usage, thereby lowering operational costs and alleviating power infrastructure strain.
Implementation Method 1
a bidirectional converter configured to perform power conversion in two directions, the two directions being a direction of charging the power storage device of the EV connected to the charging/discharging station, and a direction of discharging the power storage device of the EV connected to the charging/discharging station
Data Source
AI summary
An EV charging apparatus includes: a plurality of charging stations respectively connected detachably with EVs, the plurality of charging stations being configured to charge power storage devices mounted in the EVs when connected; a plurality of power supply circuits configured to convert power supplied from a power system side into direct current power compatible with the EVs, and to supply the direct current power after the conversion respectively to the plurality of charging stations; a charging/discharging station connected detachably with the EV, the charging/discharging station being configured to charge and discharge the power storage device mounted in the EV when connected; and a bidirectional converter configured to perform power conversion in two directions, the two directions being a direction of charging the power storage device of the EV connected to the charging/discharging station, and a direction of discharging the power storage device of the EV connected to the charging/discharging station.