Auxiliary Protection Circuit for Electric Sealed Compressor Control
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Solution Overview
Problem
In electric sealed compressors, the self-protection function of the IPM may fail if the microcontroller cannot detect abnormality signals, leading to heat generation and incorrect operation due to overcurrent, overheat, or control voltage abnormalities.
Innovation Solution
A control device with a power converter, driving circuit, abnormality detection element, controller, and auxiliary protection circuit is implemented, where the auxiliary protection circuit deactivates the driving circuit in response to abnormality detection signals, ensuring reliable protection even if the controller fails to perform self-protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only the controller performs self-protection function detection, then the control device structure is simple, but the reliability is insufficient when controller detection fails
Solution Approach 1:
The auxiliary protection circuit is configured to perform preliminary protection action by detecting abnormality signals directly from the IPM and independently deactivating the driving circuit when abnormalities are detected, without waiting for the controller's response. This preliminary action ensures protection even when the controller fails to detect or respond to abnormality signals.
Solution Approach 2:
The auxiliary protection circuit acts as an intermediary between the IPM and the driving circuit. It receives abnormality signals from the IPM and directly controls the driving circuit activation, providing an independent protection pathway that bypasses the controller's software-based detection and response mechanisms.
2Reliability
If the controller stops outputting control signal upon detecting abnormality, then the protection response is fast, but the protection is ineffective when the controller cannot detect the abnormality signal
Solution Approach 1:
The auxiliary protection circuit is pre-configured to directly respond to abnormality signals from the IPM by deactivating the driving circuit. This preliminary configuration ensures that protection action is taken immediately when abnormalities occur, without relying on the controller's software detection and response capabilities.
Solution Approach 2:
The auxiliary protection circuit serves as an intermediary protection layer between the IPM and the driving circuit. It independently monitors IPM status through abnormality signals and directly controls the driving circuit, providing effective protection even when the controller's detection system fails.
Data Source
AI summary
A control device (100) of an electric sealed compressor of the present invention comprises a power converter (30) which supplies electric power to an electric motor (5) of the electric sealed compressor; a driving circuit (27) which drives the power converter (30); abnormality detector (40) which detects abnormality in an abnormality detection region including the power converter (30) and the driving circuit (27); a controller (11) configured to output a control signal for driving the power converter to the driving circuit (27) and stop outputting the control signal in response to a signal (Fo signal) output from the abnormality detector (40), the signal indicating that the abnormality has been detected; and an auxiliary protection circuit (50) configured to deactivate the driving circuit (27) in response to the signal output from the abnormality detector (40), the signal indicating that the abnormality has been detected.