Charging Contactor Circuit for EV Voltage Type Detection
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Solution Overview
Problem
Existing charging systems for electric vehicles face challenges in reliably detecting the voltage type (direct current or alternating current) to ensure safe operation and compliance with safety standards like ASIL D without requiring software upgrades to existing battery management systems.
Innovation Solution
A circuit arrangement using a differential amplifier and comparator with integrated low-pass filter and galvanic isolation components to safely detect voltage type, generating a digital level for controlling charging contactors, eliminating the need for software upgrades by ensuring hardware-based detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-based voltage detection is used in existing battery management systems, then the system can detect voltage type, but the system requires upgrading to ASIL level D which increases hardware and software costs
Solution Approach 1:
The patent segments the voltage detection function from the main battery management system by implementing a dedicated hardware circuit arrangement. This separate circuit performs voltage type detection independently, eliminating the need to upgrade the entire battery management system to ASIL level D and reducing overall system complexity while maintaining detection reliability
Solution Approach 2:
The patent introduces an intermediary hardware circuit arrangement that acts as a mediator between the charging system and the battery management system. This intermediate circuit handles the complex voltage type detection and ASIL D compliance requirements, allowing the existing battery management system to remain unchanged while still achieving safe operation
2Ease of manufacture
If hardware-based voltage detection circuit is implemented, then existing battery management systems do not need upgrading, but additional hardware components are required
Solution Approach 1:
The patent merges multiple functions into a single integrated circuit arrangement: voltage type detection, low-pass filtering, differential amplification, and galvanic isolation are combined in one compact hardware module. This integration simplifies manufacturing and system assembly while the internal complexity is managed through functional consolidation
Solution Approach 2:
The circuit arrangement is designed with universal applicability to work with existing battery management systems without requiring upgrades. The hardware circuit performs multiple functions (detection, filtering, isolation) that make it compatible with various charging systems while maintaining ease of manufacture through standardized components
3Measurement precision
If differential amplifier with low-pass filter is used, then voltage type detection is safe and reliable, but the circuit complexity increases
Solution Approach 1:
The low-pass filter is implemented as a preliminary action before the voltage comparison. By pre-filtering the input voltage signal to remove alternating current components before they reach the differential amplifier and comparator, the circuit achieves precise DC voltage detection without requiring complex real-time analysis, thereby reducing overall circuit complexity while maintaining measurement precision
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
Enables safe and reliable detection of voltage type, meeting safety standards without upgrading existing battery management systems, reducing costs and ensuring safe operation of charging contactors.
Implementation Method 1
at least one differential amplifier having two inputs and one output. In one operating state of the circuit arrangement, the first input of the differential amplifier is electrically coupled to a first pole of an input voltage supply
Implementation Method 2
a low-pass filter can be arranged between the output of the differential amplifier and its second input. In particular, the low-pass filter can have at least one capacitor and a resistor connected electrically in parallel with the capacitor. Alternating voltage components can be conveniently eliminated by means of the low-pass filter.
Implementation Method 3
a comparator having two inputs and one output, the first input of which is electrically coupled to the output of the differential amplifier and the output of which is electrically coupled to a control cable of the at least one charging contactor
Data Source
AI summary
A circuit arrangement for controlling at least one charging contactor of a charging system of an electrically operated vehicle includes at least one differential amplifier having two inputs and one output. The first input is electrically coupled to a first pole of an input voltage supply of the charging system for supplying an input voltage and the second input is electrically coupled to a second pole of the input voltage supply. The arrangement also includes a comparator having two inputs and one output. The first input is electrically coupled to the output of the differential amplifier and the output is electrically coupled to a control cable of the at least one charging contactor of the charging system.