Output Voltage Sensing Fault Detection in Power Converter Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power converters can mistakenly detect low output voltages due to open or short circuits in the output voltage sense lines during startup, leading to excessively high voltages that can damage expensive loads.
Innovation Solution
A control circuit that determines a fault condition by analyzing the output current and voltage signals, using software or hardware comparators to detect if the current exceeds a threshold while the voltage remains below a threshold, synchronizing these comparisons to identify incorrect voltage sensing, and shuts down the power converter if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the control circuit relies solely on the voltage sense line to control power converter operation, then the control system remains simple, but the system becomes vulnerable to faulty voltage sensing that can cause excessively high output voltages and damage loads
Solution Approach 1:
The control circuit continuously monitors the relationship between output voltage and output current during operation. By establishing a feedback mechanism that compares actual voltage-current correspondence against expected characteristics, the system can detect when voltage sensing becomes faulty and take corrective action, such as shutting down the power converter or adjusting control parameters.
Solution Approach 2:
The output current signal serves as an intermediary parameter to indirectly verify the accuracy of voltage sensing. Instead of directly monitoring voltage sense line integrity, the system uses current as a mediator to infer whether voltage measurements are accurate, based on the known relationship between voltage and current in the power converter's operation.
2Measurement precision
If additional hardware elements such as current sources or comparators are added to detect voltage sensing faults, then detection capability improves, but device complexity and cost increase
Solution Approach 1:
The control circuit uses its existing processing capabilities to analyze the relationship between voltage and current signals. The system's own control logic and signal processing resources are leveraged to perform fault detection without requiring dedicated detection hardware, making the existing components serve dual purposes.
Solution Approach 2:
The control circuit is designed to handle multiple functions: normal power conversion control, voltage sensing verification, and fault detection. By making the control circuit universal and capable of performing these diverse functions, the patent eliminates the need for separate dedicated hardware for each function, reducing overall system complexity.
3Reliability
If the control circuit continuously monitors both voltage and current signals to detect fault conditions, then detection reliability improves, but processing requirements and complexity increase
Solution Approach 1:
The control circuit establishes expected voltage-current relationship characteristics in advance, during normal system design and commissioning. By pre-defining the normal operational relationship between voltage and current, the system can quickly compare real-time measurements against these predetermined expectations without requiring complex real-time analysis algorithms.
Solution Approach 2:
The system monitors changes in the relationship parameters between voltage and current rather than analyzing absolute values. By focusing on the relationship parameters and their changes over time, the fault detection becomes simpler and more robust, requiring less complex processing while maintaining high reliability.
Data Source
AI summary
A control circuit and a corresponding method is presented. The control circuit may be configured to control a power converter. The control circuit may be configured to receive a voltage signal indicative of an output voltage at an output of the power converter. The control circuit may be configured to receive a current signal indicative of an output current at the output of the power converter. The control circuit may be configured to determine a fault condition associated with the voltage signal based on the current signal and based on the voltage signal. By determining a fault condition based on an analysis of the sensed output voltage and the sensed output current, it becomes possible to detect the fault condition in a simple and efficient manner.