Relay Drive Circuit Dynamic Current Switching
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Solution Overview
Problem
Conventional relay drive circuits consume excessive power and produce heat due to continuous holding currents, which are necessary to prevent external disturbances from turning the relay off, but these currents are not needed when no disturbance is present, leading to unnecessary power consumption and heat generation.
Innovation Solution
A relay drive circuit with a first and second current setting portion, a current switching portion, and a plate-OFF detecting portion that switches the coil current to a higher value only when an external disturbance is detected, using a highpass filter to monitor potential changes at the coil ends to prevent the relay from turning off and optimize current usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a holding current with excessive current value is supplied to prevent external disturbance from turning the relay OFF, then the relay reliability is improved, but the power consumption increases
Solution Approach 1:
The patent applies dynamics by switching between two different current values (first current value for anti-disturbance protection, second current value for normal operation) based on the detection of plate OFF-tendency. The current supplied to the coil is not static but dynamically adjusted according to the relay's operational state, allowing the system to maintain reliability only when necessary while reducing power consumption during normal operation.
Solution Approach 2:
The patent implements feedback through the plate-OFF detecting portion that monitors the coil's potential change to detect OFF-tendency. This detection mechanism provides feedback to the current switching portion, which then adjusts the coil current accordingly. The feedback loop enables the system to respond to actual relay state changes and external disturbances, maintaining stability only when needed.
2Reliability
If a holding current with excessive current value is supplied to prevent external disturbance from turning the relay OFF, then the relay reliability is improved, but the heat production increases
Solution Approach 1:
The patent applies dynamics by switching between two different current values (first current value for anti-disturbance protection, second current value for normal operation) based on the detection of plate OFF-tendency. The current supplied to the coil is not static but dynamically adjusted according to the relay's operational state, allowing the system to maintain reliability only when necessary while reducing power consumption during normal operation.
Solution Approach 2:
The patent implements feedback through the plate-OFF detecting portion that monitors the coil's potential change to detect OFF-tendency. This detection mechanism provides feedback to the current switching portion, which then adjusts the coil current accordingly. The feedback loop enables the system to respond to actual relay state changes and external disturbances, maintaining stability only when needed.
3Reliability
If the coil current is set to a higher first current value, then the plate can be drawn to the core and contacts can make reliable contact, but the power consumption increases
Solution Approach 1:
The patent applies segmentation by dividing the current supply into two distinct modes: a first current value mode for initial plate attraction and contact closure, and a second current value mode for maintaining contact closure. This segmentation allows the system to use high current only when necessary for reliable contact establishment, then switch to low current for maintenance, thereby reducing overall power consumption while ensuring contact reliability.
Solution Approach 2:
The patent implements periodic action through the alternating supply of first and second current values based on the detection of plate OFF-tendency. The system periodically switches between high current (when OFF-tendency is detected) and low current (during normal operation), creating a rhythmic current supply pattern that ensures contact reliability only when needed while minimizing power consumption during stable operation.
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 solution reduces the likelihood of the relay turning off due to external disturbances without continuous high current supply, thereby minimizing power consumption and heat production.
Implementation Method 1
The plate-OFF detecting portion detects, based on change of a potential at an end of the coil, OFF-tendency in which the plate is about to get apart from a head of a core of the relay.
Implementation Method 2
the plate-OFF detecting portion may include a highpass filter for passing only high frequency components in the potential at the low-side of the coil
Implementation Method 3
a first drive portion sets a coil current to be supplied to a coil to a first current value with which a plate of an electromagnetic relay is drawn and a movable contact of the relay comes in contact with a fixed contact of the relay
Data Source
AI summary
A potential of an end of the coil is inputted to a plate-OFF detecting portion which detects OFF-tendency in which a plate of a relay is about to get apart from a head of a core of the relay. When the OFF-tendency is detected, a coil current for supplying a coil of the relay is set to a first current value with which a plate of an electromagnetic relay is drawn and a movable contact of the relay comes in contact with a fixed contact of the relay. When an external disturbance ends, the coil current is returned to a second current value, which is smaller than the first current value, so that the movable contact and the fixed contact are kept in contact with each other.