Dual-Circuit Charge Switch Control for AC/DC Charging Isolation
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Solution Overview
Problem
Conventional charging systems face the challenge of preventing a switch that connects an inlet and a battery in a DC charging circuit from being turned on during AC charge, which could lead to improper power application.
Innovation Solution
A control device with dual control circuits is implemented to manage the switching between AC and DC charging. The first control circuit and the second control circuit independently determine the charging mode and send commands to turn off the switch when AC charge is executed, ensuring the switch remains off even if one circuit fails to do so.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single control circuit is used to manage switching between AC and DC charging, then the device complexity is reduced, but the reliability of preventing the switch from being turned on during AC charge deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by implementing a dual control circuit structure where two independent control circuits (first control circuit and second control circuit) both control the same switch. This redundant configuration is established in advance to cushion against the risk of one control circuit failing to properly turn off the switch during AC charging, thereby preventing DC voltage from being applied to the AC power source.
2Reliability
If redundant control circuits are implemented to improve reliability, then the reliability of preventing switch misoperation improves, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the control function into two separate, independent control circuits (first control circuit and second control circuit). Each control circuit independently determines whether to perform AC charging or DC charging and independently controls the switch. This segmentation allows the system to achieve higher reliability through redundancy while keeping each individual control circuit relatively simple.
Solution Approach 2:
The patent applies universality by having both control circuits perform the same dual function: determining the charging mode (AC or DC) and controlling the switch accordingly. This multi-functionality approach allows the redundant system to maintain simplicity in each component while achieving overall system reliability through the universal application of the control logic across multiple circuits.
Data Source
AI summary
A control device includes a PWC circuit (first control circuit) that controls on/off of a DCR (switch) that connects the inlet and the battery pack (a battery) in the DC charging circuit, and an EV-ECU (a second control circuit) that controls on/off of DCR. Each of PWC circuit and EV-ECU operates to determine which of AC charge and DC charge is to be performed, and to turn off DCR if it is determined that AC charge is to be performed.