EV Inverter Galvanic Interface Detection for Open Bond Wires
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Solution Overview
Problem
Inverters for electric vehicles face challenges in detecting open bond wires in galvanic interfaces, which can lead to interference and incorrect command propagation due to electromagnetic interference, resulting in potential damage from delayed fault detection.
Innovation Solution
A system with separate signal paths through first and second galvanic isolators, bias networks, filters, and amplifiers, coupled with an open detector, allows for real-time detection of open bond wires by comparing amplified signals and initiating mitigation actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If galvanic isolators are used to separate low voltage and high voltage areas, then electromagnetic interference is reduced, but detection of open bond wires becomes more difficult
Solution Approach 1:
The patent introduces an intermediary detection circuit that couples to the galvanic isolator output path to detect open bond wires. This intermediary detector allows measurement of the isolated signal path without breaking the galvanic isolation, thus maintaining EMI protection while enabling fault detection.
Solution Approach 2:
The patent replaces direct electrical contact measurement with capacitive coupling measurement. By using the inherent capacitance of the galvanic isolator as the measurement interface, the system can detect open bond wires through the isolated barrier without direct electrical connection, maintaining isolation while enabling detection.
2Reliability
If separate signal paths through multiple galvanic isolators are used, then fault detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the detection circuit multi-functional by designing it to work with either one or two galvanic isolators. The same detection circuitry can detect open bond wires in single-isolator configurations or compare signals from dual-isolator configurations, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The patent implements a dynamic detection approach where the system can adapt between different operating modes (single isolator or dual isolator) based on the actual hardware configuration. This dynamic flexibility allows the system to achieve high reliability when needed while reducing complexity when the simpler single-isolator approach suffices.
Data Source
AI summary
A system comprises an inverter including a first galvanic isolator separating a low voltage area from a high voltage area, a second galvanic isolator separating the low voltage area from the high voltage area, a first bias network connected to the first galvanic isolator, a second bias network connected to the second galvanic isolator, a first filter connected to the first bias network, a second filter connected to the second bias network, a first amplifier connected to the first filter, a second amplifier connected to the second filter, and an open detector connected to the first amplifier and the second amplifier.