EV Charging Handshake Using Frequency Scaling for High-Power AC
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Solution Overview
Problem
Existing electric vehicle charging technologies are limited by a maximum AC current of 80A, restricting AC charging to 19.2 kW, which is insufficient for high-power electric vehicles, and existing EVSEs and on-board charging systems cannot support higher currents needed for faster charging without infrastructure replacement.
Innovation Solution
Implement handshaking techniques between EVs and EVSEs to determine current limits and charging capabilities, scaling AC power using different frequencies to enable on-board chargers to convert AC power to DC power exceeding 19.2 kW, while maintaining compatibility with standard charging systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AC charging is limited to 80A maximum current following J1772 standards, then compatibility with existing charging infrastructure is maintained, but charging power is restricted to 19.2 kW which is insufficient for high-power electric vehicles
Solution Approach 1:
The patent implements dynamic frequency scaling where the EVSE adjusts the frequency of the AC power signal based on the charging capability detected during handshake. When a high-power capable vehicle is detected, the system transitions from standard frequency (60 Hz) to scaled frequency (e.g., 120 Hz or higher), enabling the on-board charger to interpret this as a directive to operate at elevated power levels beyond the standard 19.2 kW limit while maintaining physical compatibility with existing J1772 connectors and protocols
Solution Approach 2:
The system changes the frequency parameter of the AC power signal as a communication mechanism. By varying the frequency from the standard 60 Hz to higher values, the EVSE conveys charging capability information to the vehicle's on-board charger, which then adjusts its DC conversion capability accordingly. This parameter change enables power levels exceeding 19.2 kW without requiring new connector standards or infrastructure replacement
2Reliability
If existing EVSEs and on-board chargers operate at standard frequencies, then compatibility with current standards is maintained, but charging speed is insufficient for high-power electric vehicles requiring faster charging
Solution Approach 1:
The patent utilizes periodic AC power delivery at scaled frequencies during the charging session. Once high-power mode is established through frequency-based handshake, the EVSE delivers power at elevated frequencies (e.g., 120 Hz, 180 Hz, or 240 Hz), which corresponds to shorter half-cycles and enables the on-board charger to process and convert higher power levels to DC, thereby increasing charging speed while maintaining periodic AC delivery characteristics
Solution Approach 2:
The system implements feedback through the frequency signal itself. During handshake, the EVSE monitors the vehicle's response to frequency variations to determine on-board charger capability. The vehicle's acceptance or rejection of scaled frequency signals provides feedback about its power handling capacity, allowing the EVSE to dynamically adjust and optimize charging power delivery in real-time
3Power
If the AC current limit is increased above 80A, then charging power can exceed 19.2 kW for high-power vehicles, but existing charging infrastructure and safety standards cannot support higher currents
Solution Approach 1:
The patent introduces frequency scaling as an intermediary communication layer between the EVSE and the vehicle's on-board charger. Rather than directly increasing current limits and requiring infrastructure upgrades, the system uses frequency-modulated signals as an intermediary mechanism to negotiate and enable higher power delivery through existing 80A-limited infrastructure, with the actual current increase handled dynamically by the vehicle's own on-board charging system
Data Source
AI summary
Described herein are systems and methods for charging electric vehicles using handshake communication techniques. Systems and methods may include establishing communication between an electric vehicle (EV) and an electric vehicle supply equipment (EVSE) and initiating a charging session providing AC power to the EV. A current limit for an on-board EV charger may be determined based on a duty cycle associated with a signal from the EVSE, and the current limit may indicate a charging capability for the on-board EV charger When the charging capability is greater than a threshold amount, such as 19.2 kW, the AC power may be scaled to a second frequency to enable high-power charging.