EV Active Discharge Circuit Self-Diagnostics During Shutdown
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Solution Overview
Problem
Existing electric vehicles (EVs) lack a diagnostic capability to determine if the discharge circuit, used to dissipate energy from the DC link capacitor during shutdown events, is operational or deficient.
Innovation Solution
A discharge system with a diagnostic check, comprising a discharge circuit connected in parallel to the drive system, a sensor to detect electrical characteristics, and a control system to operate the discharge circuit and provide notifications based on the detected responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discharge circuit is provided in the drive system to dissipate energy from the DC link capacitor, then the system can safely discharge energy during shutdown events, but there is no diagnostic capability to determine if the discharge circuit is operational or deficient
Solution Approach 1:
The control system performs self-diagnostics by activating the discharge circuit and monitoring the electrical characteristic through the sensor. The system compares the monitored characteristic against expected values to determine if the discharge circuit is operational, providing feedback about the circuit's health status without requiring external diagnostic equipment.
Solution Approach 2:
The discharge circuit system performs its own self-diagnostics using the existing sensor and control system. The control system activates the discharge circuit and monitors its electrical characteristic to determine operational status, allowing the system to self-assess its health without requiring separate diagnostic tools or procedures.
2Reliability
If a sensor is added to detect electrical characteristics of the discharge circuit, then diagnostic capability is enabled, but the device complexity increases
Solution Approach 1:
The sensor serves multiple functions: it monitors electrical characteristics during normal operation and also enables self-diagnostics by detecting the electrical characteristic when the control system activates the discharge circuit. This multi-functionality allows the same sensor to support both operational monitoring and diagnostic capabilities without requiring additional dedicated diagnostic sensors.
Solution Approach 2:
The system uses its existing sensor and control system to perform self-diagnostics. The control system activates the discharge circuit and the sensor monitors the resulting electrical characteristic, allowing the system to self-assess its operational status without requiring external diagnostic equipment or additional complex diagnostic infrastructure.
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 self-diagnostic checks to identify if the discharge circuit is operational or deficient, ensuring safe and efficient energy dissipation during shutdown events and providing timely notifications for further analysis.
Implementation Method 1
The sensor is arranged in series with the discharge circuit to detect an electrical characteristic of the discharge circuit
Data Source
AI summary
A discharge system for a drive system includes a discharge circuit, a sensor, and a control system. The discharge circuit is connected in parallel to the drive system, and is operable in an ON-position to be electrically coupled to the drive system or an OFF-position to be electrically decoupled from the drive system. The sensor is arranged in series with the discharge circuit to detect an electrical characteristic of the discharge circuit. The control system is configured to, for a diagnostic check, operate the discharge circuit in the ON-position, and provide a notification in response to the electric characteristic detected being unresponsive to the discharge circuit being in the ON-position.