EV Overcurrent Protection Circuit for Reverse Surge During Charging
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Solution Overview
Problem
Electric vehicles face issues with reverse surge overcurrent during charging, which can damage the motor driving device, and existing technologies do not effectively protect against such overcurrent.
Innovation Solution
The electric vehicle incorporates a motor with multiple windings, two inverters, and an overcurrent protection circuit with a charging capacitor and parallel-connected elements to manage current flow in both directions, using a controller to control switch states and alleviate damage from reverse surge overcurrent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single inverter is used to drive the motor, then the device complexity is reduced, but the motor cannot provide sufficient torque in both low and high power periods
Solution Approach 1:
The patent employs two inverters (first inverter and second inverter) that can operate independently or in combination to cover both low power and high power periods. The first inverter handles low power operations while the second inverter provides additional capacity for high torque requirements, making the system universally capable across the entire operating range.
Solution Approach 2:
The patent dynamically switches between different inverter configurations based on power requirements. A mode switch controls whether the motor operates in closed-end winding mode (using only the first inverter) or open-end winding mode (using both inverters), allowing the system to adapt its complexity to the actual power needs.
2Use of energy by moving object
If the main operating point is positioned in the high voltage utilization period, then fuel efficiency is improved, but the maximum torque and acceleration performance deteriorate
Solution Approach 1:
The patent dynamically adjusts the motor winding configuration through mode switching. During low power periods, the system operates in closed-end winding mode to achieve high voltage utilization and improve fuel efficiency. During high power periods requiring maximum torque, the system switches to open-end winding mode, ensuring both fuel efficiency and performance requirements are met at different operating points.
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
The solution effectively protects the motor driving device from reverse surge overcurrent, ensuring stable charging and reducing the risk of damage, thereby maintaining normal vehicle operation and minimizing replacement costs.
Implementation Method 1
a first element connected in series with the charging capacitor and selectively allowing current conduction in a first direction depending on a turn-on/off state
Implementation Method 2
a second element connected in parallel with the first element and allowing current conduction in a second direction opposite to the first direction
Implementation Method 3
an overcurrent protection circuit including a charging capacitor
Data Source
AI summary
An electric vehicle including an overcurrent protection circuit that includes a charging capacitor, a first element connected in series with the charging capacitor and selectively allowing current conduction in a first direction depending on a turn-on/off state, and a second element connected in parallel with the first element and allowing current conduction in a second direction opposite to the first direction, and is connected between DC terminals and a node formed by connecting one end of each of a plurality of switches.