Solenoid Drive Circuit Failure Detection via Duty Control
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Solution Overview
Problem
Existing solenoid drive devices face challenges in accurately determining failures in solenoid drive circuits and selection circuits due to erroneous interpretations of current detection signals, leading to incorrect failure determinations.
Innovation Solution
A solenoid drive device with a control element that performs on/off duty control of switching elements in synchronized cycles, using a selection circuit to select current detection signals and determine failures based on the change characteristics of selection detection signals, distinguishing between normal and faulty states by reversing switching directions and analyzing current variations at specific sampling times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a selection circuit is used to select current detection signals from multiple solenoid drive circuits, then the device complexity is reduced, but the reliability of failure determination deteriorates due to inability to distinguish between selection circuit failures and solenoid drive circuit failures
Solution Approach 1:
The control element performs preliminary actions by setting specific on/off states for switching elements in solenoid drive circuits before sampling current detection signals. By pre-configuring the switching elements to known states (ON or OFF) and then sampling the resulting current values, the system creates predictable reference conditions that enable reliable failure determination even with a shared selection circuit.
Solution Approach 2:
The control element uses feedback by comparing sampled current detection signals against expected values based on the predetermined switching states. The control element determines the state of switching elements by analyzing the feedback from current detection signals, and can identify failures when the feedback does not match the expected behavior for the given switching configuration.
2Measurement precision
If current detection signals are sampled at arbitrary timing, then the measurement precision is reduced, but the ease of operation is improved
Solution Approach 1:
The control element implements periodic action by sampling current detection signals at specific periodic intervals within control cycles. The sampling timing is synchronized with the periodic switching operations of the solenoid drive circuits, ensuring that current values are captured at consistent, meaningful points in each cycle when the switching elements are in predetermined states.
3Productivity
If switching elements are controlled in different control cycles, then the productivity is improved, but the reliability of failure determination deteriorates due to inability to compare current values under consistent conditions
Solution Approach 1:
The control element merges the control of multiple solenoid drive circuits by performing control operations for different circuits within the same control cycle. By coordinating the switching operations and sampling timing across multiple drive circuits in a unified control framework, the system maintains consistent reference conditions for reliable failure determination while efficiently managing multiple circuits simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables precise failure determination of solenoid drive circuits and selection circuits without additional failure determination circuits, improving accuracy by analyzing current variations and switching states, thus preventing erroneous failure diagnoses.
Implementation Method 1
a first solenoid, a first switching element configured to perform duty control of an application voltage of the first solenoid
Data Source
AI summary
A solenoid drive device includes a first solenoid drive circuit, a second solenoid drive circuit, a selection circuit, and circuitry. The circuitry controls the first switching element and the second switching element with a duty control in a control cycle according to acquired values of the first drive current and the second drive current so that a first on/off switching direction of the first switching element at a start timing of the control cycle is opposite to a second on/off switching direction of the second switching element at the start timing. The circuitry determines whether a failure in at least one of the selector, the first solenoid drive circuit, and the second solenoid drive circuit occurs based on a change in the selection detection signal in a period during which an on/off state of the first switching element is different form an on/off state of the second switching element.