Drive Device Solenoid Valve Short Circuit Detection
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Solution Overview
Problem
Existing solenoid abnormality detection devices cannot distinguish between battery short circuits and ground short circuits, limiting their ability to precisely detect these types of faults in solenoid valves.
Innovation Solution
A drive device connected to a solenoid valve with a high-side switching element connected to the positive electrode of a battery and a low-side switching element connected to the ground, featuring an overcurrent detection unit that differentiates between battery and ground short circuits by monitoring currents through specific current paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage monitoring is used to detect short circuit abnormalities, then detection capability is provided, but the ability to distinguish between battery short circuit and ground short circuit is lost
Solution Approach 1:
The detection function is segmented into two independent detection paths: one for detecting battery short circuits (by monitoring voltage at the battery connection point) and another for detecting ground short circuits (by monitoring voltage at the ground connection point). This segmentation allows each path to independently detect its specific fault type, thereby resolving the inability to differentiate between short circuit types while maintaining comprehensive detection capability.
2Device complexity
If a single detection method is used for all short circuits, then device complexity is reduced, but detection precision for different short circuit types deteriorates
Solution Approach 1:
The detection system is divided into two independent detection paths with separate monitoring points: one path monitors the voltage between the battery terminal and ground to detect battery short circuits, while the other path monitors the voltage between the ground terminal and chassis to detect ground short circuits. This segmentation maintains relatively simple device structure while achieving precise differentiation between short circuit types.
3Device complexity
If voltage monitoring at a single point is implemented, then the detection system remains simple, but the ability to identify specific short circuit locations is lost
Solution Approach 1:
The monitoring system is segmented into two independent monitoring points: the first monitoring point detects voltage changes at the battery connection point to identify battery short circuits, while the second monitoring point detects voltage changes at the ground connection point to identify ground short circuits. This segmentation preserves information about the specific location of short circuits while keeping the monitoring circuit configuration relatively simple.
Solution Approach 2:
The patent introduces voltage as an intermediary parameter to indirectly detect short circuit locations. By monitoring voltage changes at different points in the circuit (battery terminal and ground terminal), the system can infer the location of short circuits without directly detecting the fault, thus preserving location information while maintaining system simplicity.
Data Source
AI summary
A drive device includes: a first current path that has a high-side MOSFET; a second current path that has a low-side MOSFET; and a third current path connected to the other end portion of a coil and positioned between the first current path and the second current path. The drive device further includes: PWM drive circuits that generate a drive signal through PWM control; and an overcurrent detection circuit that detects that an overcurrent has flowed through the current paths. It is possible to precisely detect the occurrence of a battery short circuit and a ground short circuit by detecting which of the first current path and the second current path an overcurrent has flowed through.