Bidirectional EVSE Control for Safe AC/DC V2X Mode Switching
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Solution Overview
Problem
Current Vehicle-to-Everything (V2X) technologies face challenges in efficiently managing bidirectional power flow and ensuring safety between electric vehicles (EVs) and the grid, particularly due to complex communication, control, and safety issues in AC V2X systems, and high costs associated with DC V2X systems, leading to inefficient and hazardous islanding and reconnection scenarios.
Innovation Solution
A bidirectional electric vehicle supply equipment (EVSE) with a voltage sensor, smart circuit breaker, backup control power, and communications controller that senses grid and EV voltages, manages power flow, and communicates with the EV and control panel to select and perform various operation modes safely and efficiently, including V2H and V2G modes, using PWM handshaking procedures and adjustable protections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If AC V2X technology is used for bidirectional power flow, then lower upfront costs are achieved, but complex communication and control issues arise leading to safety hazards
Solution Approach 1:
The patent introduces a bidirectional EVSE as an intermediary device between the EV and the grid/building loads. This EVSE includes a communications controller that manages all communication and control functions, and a smart circuit breaker that provides safety protection. By placing this intelligent intermediary in the power flow path, the system achieves safe bidirectional power exchange without requiring complex communication protocols between the EV and end devices, thus maintaining low cost while improving safety.
Solution Approach 2:
The bidirectional EVSE incorporates a communications controller that continuously monitors system status and exchanges information with the EV, control panel, and aggregator. This feedback mechanism enables real-time detection of fault conditions, proper mode selection (charging, V2H, V2G), and coordinated control of the smart circuit breaker. The feedback loop ensures safe operation by detecting anomalies and triggering appropriate protective actions without requiring complex direct communication between EV and loads.
2Reliability
If DC V2X technology is used for bidirectional power flow, then safety is improved, but high costs are incurred
Solution Approach 1:
The bidirectional EVSE serves as a cost-effective intermediary that provides DC-level safety functions in an AC system. The smart circuit breaker within the EVSE offers selective disconnect capabilities similar to DC systems, while the communications controller manages power flow control. This approach achieves DC-like safety and control without requiring expensive DC charging infrastructure, thus maintaining cost-effectiveness while improving reliability.
3Adaptability or versatility
If bidirectional power flow management is implemented, then V2X applications are enabled, but complex communication protocols are required
Solution Approach 1:
The patent merges all communication and control functions into a single bidirectional EVSE device. The communications controller within the EVSE handles communication with the EV, control panel, and aggregator, managing mode selection and power flow coordination. This consolidation enables versatile V2X applications (V2H, V2G, charging) while avoiding the need for complex distributed communication protocols between multiple independent devices, thus reducing overall system complexity.
4Reliability
If smart circuit breaker is added to EVSE, then safety protection is improved, but device complexity increases
Solution Approach 1:
The smart circuit breaker in the bidirectional EVSE is designed to perform multiple functions: providing fault protection, enabling selective disconnect of EV/grid/loads, supporting bidirectional power flow control, and facilitating communication coordination. By integrating these diverse functions into a single multi-functional device, the system achieves improved safety and reliability without proportionally increasing device complexity, as the smart circuit breaker serves as a universal protection and control element for all system configurations.
Data Source
AI summary
A bidirectional electric vehicle supply equipment (EVSE) for use in a power distribution system having an EV, an electric grid, a control panel and an aggregator or grid operator. The bidirectional EVSE includes a voltage sensor structured to sense grid voltage and EV voltage; an EVSE smart circuit breaker coupled to the voltage sensor and structured to connect or disconnect the EV based on a signal from the voltage sensor and to disable a PWM signal before opening EVSE contactors, an EVSE backup control power structured to provide control power to the bidirectional EVSE when the electric grid is not available; and a bidirectional EVSE communications controller structured to communicate with the EV, the control panel and the aggregator during selecting an operation mode, transitioning to a selected operation mode, and performing operation and oversight protection in the selected operation mode.