Electrical Circuit Diagnosis via Sequential Switching and Code Correlation
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Solution Overview
Problem
Current electrical circuit diagnostic methods in SCR systems, such as those used in BLDC motors for aqueous urea solutions, struggle to differentiate between various errors in complex electrical circuits, especially when components are not activated, due to the lack of precise voltage and current measurements.
Innovation Solution
The method involves adding an additional switch to the circuit, allowing for sequential activation and deactivation of branches, with corresponding voltage and current measurements, to generate status and measurement codes that can be correlated to diagnose correct functioning or malfunctioning of circuit elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single static measurement of voltage and/or current is performed in the different branches or devices, then the measurement process is simple, but it is impossible to differentiate between different errors
Solution Approach 1:
The circuit is divided into multiple branches with individual switches (K1, K2, K3, etc.) that can be activated independently. Each branch can be tested separately by closing its corresponding switch, allowing static measurements to be performed on specific segments rather than the entire circuit at once. This segmentation enables error differentiation while keeping each measurement step simple.
Solution Approach 2:
Before performing measurements, the system pre-configures multiple circuit statuses by defining which switches should be closed for each test scenario. The controller sequentially activates predetermined switch combinations (e.g., closing K1 for branch 1 test, then K2 for branch 2 test) before taking measurements. This preliminary configuration of circuit states enables systematic error identification without requiring complex real-time decision-making during measurement.
2Reliability
If multiple switches are added to create different circuit statuses for sequential measurements, then error differentiation is improved, but the device complexity increases
Solution Approach 1:
The additional switches (K1, K2, K3, etc.) serve multiple functions: they act as circuit closure elements for normal operation and simultaneously serve as diagnostic selectors for error identification. Each switch is associated with a specific branch or device, allowing the same hardware component to participate in both operational and diagnostic modes. This multi-functionality improves diagnostic accuracy without proportionally increasing overall system complexity.
Solution Approach 2:
The system incorporates a feedback mechanism where measurement results from each circuit status are fed back to the controller, which then determines the next switch configuration based on the observed values. The controller compares measured currents and voltages against expected ranges and uses this feedback to systematically activate or deactivate switches, narrowing down the location of potential errors through a structured diagnostic sequence rather than random switching.
3Measurement precision
If sequential activation and deactivation of branches is performed with multiple switches, then error identification capability is enhanced, but the measurement time increases
Solution Approach 1:
The diagnostic process uses periodic action by sequentially activating each switch (K1, then K2, then K3, etc.) in a predetermined sequence, allowing static measurements to be taken at each step. This periodic activation of individual branches enables systematic error identification through repeated simple measurements rather than requiring a single complex dynamic measurement, balancing time efficiency with diagnostic precision.
Solution Approach 2:
The controller pre-plans the sequence of switch activations and measurements, organizing them into an efficient diagnostic routine. By predetermined which switches to close and in what order based on the circuit topology and potential failure modes, the system minimizes the total number of measurement steps required. This preliminary planning of the diagnostic sequence reduces measurement time while ensuring comprehensive error identification coverage.
Data Source
AI summary
A method for diagnosing an electrical circuit including at least one electrical device, an actuator for the device controlled by a high side actuating switch and a low side actuating switch, and at least one additional switch not in series with any of the HS or LS switch, the method including: to each of the possible statuses of the circuit, giving a code; sequentially putting the circuit in at least some of these statuses for a given time period; during each of these periods, measuring voltage and/or current in different parts of the circuit and giving a code to the measurement; and establishing a diagnosis of correct functioning or of a malfunctioning of at least some elements of the circuit according to a pre-established correlation between the status codes and the measurement codes.