Cutoff Device Abnormality Detection in Power Converters
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Solution Overview
Problem
Existing power conversion apparatuses lack effective mechanisms for detecting abnormalities in safety shutdown circuits, which is a critical safety concern and hinders the elimination of electromagnetic contactors, thereby limiting the miniaturization and cost reduction of systems like motor control apparatuses, especially in European markets where higher safety standards like SIL3 are required.
Innovation Solution
A power conversion apparatus and method that includes a power converter, gate driver, gate drive signal generator, two cutoff devices, an analyzer, and a cutoff controller, where the analyzer determines abnormalities in the cutoff devices and controls the gate drive signal to ensure safe operation, eliminating the need for external intervention and meeting SIL3 safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two cutoff devices are used to eliminate electromagnetic contactors, then system size and cost are reduced, but the ability to detect abnormalities in the safety shutdown circuit is lost
Solution Approach 1:
The patent introduces feedback signals from each cutoff device to an analyzer. Each cutoff device outputs a feedback signal indicating its operational state, which is analyzed to detect abnormalities. This feedback mechanism enables abnormality detection without requiring external electromagnetic contactors, resolving the contradiction between system miniaturization and safety monitoring capability.
2Device complexity
If two cutoff devices are used to eliminate electromagnetic contactors, then system cost is reduced, but safety verification capability is compromised
Solution Approach 1:
The analyzer receives feedback signals from both cutoff devices and compares them with commanded states to verify safety shutdown circuit functionality. This internal verification mechanism eliminates the need for expensive external electromagnetic contactors while maintaining safety verification capability through intelligent signal analysis.
3Reliability
If feedback signals are added to each cutoff device, then abnormality detection is enabled, but device complexity increases
Solution Approach 1:
Each cutoff device generates its own feedback signal about its operational state, performing self-diagnosis. This self-service approach enables abnormality detection without requiring additional external monitoring equipment, as the cutoff devices themselves provide the necessary diagnostic information to the analyzer.
Data Source
AI summary
A power conversion apparatus includes a power converter to directly convert AC power having a frequency into AC power having a different frequency. A gate driver drives the power converter. A gate drive signal generator generates a gate drive signal supplied to the gate driver. Two cutoff devices are coupled between the gate driver and the gate drive signal generator, and supply or cut off the gate drive signal to the gate driver based on a command from an external apparatus. At least one of the two cutoff devices generates a feedback signal. An analyzer determines whether the one cutoff device has an abnormality based on the command and the feedback signal. A cutoff controller controls another one of the two cutoff devices to cut off the gate drive signal to the gate driver when the analyzer determines that the one cutoff device has the abnormality.