PFC Correction Monitoring for Early Fault Detection
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Solution Overview
Problem
Existing power supply systems face challenges in detecting and mitigating overcurrent conditions, particularly short circuits, which can lead to thermal damage and system failure, as traditional countermeasures like fuses may not trigger in time or require different ratings for various system components, leading to potential damage before detection.
Innovation Solution
The power supply system monitors the amount of correction applied by the Power Factor Correction (PFC) circuit, treating a trend towards zero correction as an indication of a fault, and isolates the input power to prevent further current flow, using a PFC fault detection condition and potentially combining it with an average current fault detection condition to trigger preventive measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional countermeasures like fuses are used to detect overcurrent conditions, then system protection is provided, but detection may not trigger in time and different ratings are required for various components
Solution Approach 1:
The patent applies preliminary action by monitoring the PFC correction amount before overcurrent damage occurs. The controller continuously tracks the correction amount and detects faults when the value approaches zero, enabling early intervention before thermal damage happens to system components.
Solution Approach 2:
The patent implements feedback by using the PFC correction amount as a real-time indicator of system health. The controller receives feedback from the PFC circuit about the correction amount and adjusts its operation accordingly, shutting down when the correction amount indicates a fault condition.
2Object-affected harmful factors
If fuses are used for system protection, then overcurrent conditions are mitigated, but different fuse ratings are needed for various system components increasing complexity
Solution Approach 1:
The patent applies universality by using a single PFC-based monitoring system that protects the entire power supply system. Instead of requiring multiple fuses with different ratings for different components, the PFC correction amount serves as a universal indicator that reflects the health of the entire system, allowing one monitoring mechanism to replace multiple protective devices.
3Reliability
If expensive countermeasures like e-fuses are used to prevent thermal damage, then system protection is improved, but cost and space increase
Solution Approach 1:
The patent applies this principle by replacing expensive e-fuses with a software-based monitoring approach using the existing PFC circuit. The PFC correction amount is already being measured for power factor correction purposes, so repurposing this data for fault detection adds minimal cost while providing effective thermal damage prevention.
Solution Approach 2:
The patent implements self-service by having the PFC circuit serve dual purposes: power factor correction and fault detection. The correction amount information generated for one function is reused for protective detection, eliminating the need for separate expensive protective devices.
Data Source
AI summary
An example power supply for supplying electrical power to an electronic device includes an AC to DC converter, power factor correction (PFC) circuitry, and a controller. The AC to DC converter is configured to convert an input AC power signal into a DC power signal. The PFC circuitry is configured to correct a power factor of the DC power signal. The controller is configured to monitor an amount of correction (φ) being applied to the DC power signal by the PFC circuitry and to shut down supply of power to the electronic device in response to φ being within a first threshold of zero degrees for a second threshold amount of time.