Power Converter Control Signal Monitoring for Fault Detection
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Solution Overview
Problem
Power converters face challenges in distinguishing between a low logical state generated by the controlling unit and a failure in the wired connection, leading to potential overcurrent and failure, due to misinterpretation of control signals.
Innovation Solution
A method and system that merge a control signal with a clock signal of higher frequency, using an XOR logical operator, to determine if a state change occurs within each period, and if not, stop signal transmission to prevent power supply according to the instructions, incorporating decoding and monitoring circuits to extract and control the power converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low logical state is transmitted to control power transistors, then the power converter can be turned off, but the power converter cannot determine if the low logical state is generated by the controlling unit or results from a failure, leading to potential misinterpretation and overcurrent
Solution Approach 1:
A monitoring device is introduced as an intermediary between the controlling unit and the power converter. This monitoring device receives the control signal, merges it with a clock signal using XOR logical operator, and monitors for state changes. The monitoring device acts as a mediator that clarifies whether a low logical state is intentional (from controlling unit) or accidental (from failure), thereby improving reliability without requiring complex modifications to the existing power converter structure.
Solution Approach 2:
The monitoring device implements a feedback mechanism by continuously monitoring the control signal and comparing it with the clock signal. When a low logical state is detected, the monitoring device checks whether a state change occurred during the clock period. If no change occurred, it indicates a failure condition and triggers an error signal. This feedback loop enables the system to distinguish between intentional off-state control and transmission failures, improving control reliability.
2Measurement precision
If the monitoring device merges control signal with clock signal using XOR logical operator, then the monitoring device can detect state changes, but the device complexity increases due to additional monitoring and decoding circuits
Solution Approach 1:
The monitoring device utilizes periodic clock signals to monitor the control signal. By merging the control signal with the periodic clock signal through XOR logical operator, the system creates a monitoring mechanism where state changes can be detected at regular intervals. The clock signal provides a periodic reference that enables precise detection of control signal transitions, improving measurement precision while maintaining a relatively simple circuit structure based on standard digital logic operations.
3Object-affected harmful factors
If the monitoring device stops transmission of control signal upon detecting failure, then overcurrent is prevented, but the productivity of the power supply system decreases due to interruption of power delivery
Solution Approach 1:
The monitoring device implements preliminary anti-action by detecting failure conditions before they can cause harmful overcurrent effects. When a failure is detected (no state change during clock period), the monitoring device immediately stops the control signal transmission to the power converter, preventing the harmful overcurrent condition. This proactive approach protects the system from damage while maintaining productivity by quickly restoring normal operation after fault clearance, rather than allowing continuous operation in a faulty state.
Data Source
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AI summary
A monitoring device (13) for monitoring a control signal (Sc) received by a power converter (1), the control signal controlling switches (9, 14) to supply an electrical load (2) is proposed. The monitoring device comprising: - a receiving circuit (26) for receiving the control signal (Sc) comprising a merging of a first variable signal (S1) and a clock signal (Sclock) having a predetermined frequency greater than the first variable signal, - a determining circuit (27) for determining if a change of state of the control signal (Sc) occurs during each period associated to the predetermined frequency, and - a monitoring circuit (29) for stopping the transmission of the control signal to the power converter so that the power converter stops to supply the electrical load according to the instructions of the first variable signal if a change of state of the control signal does not occur during one period.