Building-Side Panel Switching for EV Backup Power Isolation
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Solution Overview
Problem
In existing systems where an electric vehicle supplies power to a house during a power outage, reverse power flow to the commercial power supply can occur through the bidirectional power supply device and the AC/DC converter.
Innovation Solution
A building-side panel equipped with a power outage detector, a main breaker, and a switch that opens when a power outage is detected, preventing reverse power flow by disconnecting the charging device from the commercial power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bidirectional power supply device is used to allow power supply from electric vehicle to house, then power supply flexibility is improved, but reverse power flow to commercial power supply occurs
Solution Approach 1:
The power supply system is segmented into multiple independent circuits with separate switches (first switch between power outage detector and main breaker, second switch between charging device and main breaker). This segmentation allows selective control of different power flow paths, enabling the system to prevent reverse power flow to commercial supply while maintaining bidirectional charging capability between the building and electric vehicle.
Solution Approach 2:
The power outage detector acts as an intermediary device that monitors the commercial power supply status and controls the switches accordingly. When a power outage is detected, it opens the first switch to disconnect the charging device from the commercial power supply, thereby preventing reverse power flow while allowing the bidirectional power supply function to operate safely during normal conditions.
2Object-generated harmful factors
If switch is opened to prevent reverse power flow, then harmful reverse power flow is eliminated, but power supply path is disconnected
Solution Approach 1:
By segmenting the power supply circuit into multiple paths with independent switches, the system can disconnect only the path to commercial power supply (first switch) while maintaining the charging device connection (second switch). This ensures that power supply reliability is maintained for the building's internal needs even when preventing reverse power flow to the commercial grid.
Solution Approach 2:
The power outage detector serves as an intermediary that intelligently controls switch operations based on detected power supply conditions. It opens switches only when necessary to prevent reverse power flow, and closes them when safe to maintain power supply continuity, thus resolving the contradiction between preventing harmful flow and ensuring reliable power supply.
Data Source
AI summary
A building-side panel is provided on an exterior of a building and is to be connected to a charging device that charges an electric vehicle. The building-side panel includes: a power outage detector that detects a power outage based on a voltage supplied from a commercial power supply; a main breaker connected to the commercial power supply via the power outage detector; and a switch provided between the power outage detector and the charging device. The switch is opened when the power outage is detected.