High Voltage Interlock Strategy for Cable Connectivity Detection
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Solution Overview
Problem
The integration of power conversion circuits (PEC) with electric drive systems in vehicles poses challenges such as higher costs, reduced reliability, and safety hazards due to potential high voltage exposure when the high voltage interface cable disconnects from a remote permanent magnet synchronous machine (PMSM).
Innovation Solution
A system that includes a power circuit, an interface cable, a current sensor, and a High Voltage Interlock Strategy (HVIS) module to detect the connection status of the interface cable by using current flow information, performing pre-charging and zero-current mode detection algorithms, and initiating fault-detection actions when disconnection is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the power conversion circuit is separated from the motor to reduce costs and increase design flexibility, then manufacturing cost and design flexibility are improved, but the risk of cable disconnection and high voltage safety hazards increases
Solution Approach 1:
The system performs preliminary detection of cable connection status before high voltage energy can cause harm. The control circuit continuously monitors current flow through the cable and detects disconnection events before they can lead to safety hazards, enabling preventive action to be taken.
Solution Approach 2:
The system implements a feedback mechanism where the control circuit receives current signals from the cable, processes this information to determine connection status, and responds by controlling the discharge of high voltage energy. This closed-loop feedback ensures continuous monitoring and automatic response to connection changes.
2Reliability
If cable connector designs are modified to decrease the likelihood of disconnection, then cable connection reliability is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces mechanical cable connector design modifications with an electrical/electronic detection system. Instead of relying on more complex mechanical locking mechanisms or connector designs, the system uses a control circuit to monitor current flow and detect disconnection events, substituting mechanical prevention with electronic detection and control.
3Object-affected harmful factors
If continuous monitoring of cable connection status is implemented, then safety is improved, but device complexity increases
Solution Approach 1:
The system uses the existing current flow through the cable as the monitoring signal, eliminating the need for separate sensors or additional monitoring hardware. The control circuit leverages the operational current itself to detect connection status, allowing the system to monitor its own state using resources already present in the normal operation.
Solution Approach 2:
The control circuit serves multiple functions: it controls the normal operation of the power conversion circuit and simultaneously monitors cable connection status. By integrating these functions into a single control unit, the system avoids adding separate monitoring hardware, thereby maintaining simplicity while achieving continuous safety monitoring.
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
This solution ensures safe operation by reliably determining cable connectivity, reducing the risk of high voltage exposure and maintaining system safety without the need for costly hardware modifications, thereby enhancing design flexibility and reducing costs.
Implementation Method 1
a current sensor configured to detect current flow through the interface cable
Data Source
AI summary
A High Voltage Interlock Strategy (HVIS) uses feedback current to detect cable connectivity status for a high-voltage cable configured to connect a power conversion circuit with a remote permanent magnet synchronous machine (PMSM). One or more feedback factors are calculated based on detected feedback current. Various algorithms for calculating a feedback factor, and for determining connectivity status based on calculated feedback factors, can be practiced, according to the PMSM operational mode. Fault detection action can be performed in response to detecting a cable disconnect. The HVIS can be implemented by software, making it a safe, economical solution for cable connectivity detection.