Solid-State Switch Control System for Overheating Protection
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Solution Overview
Problem
Solid-state switches used in control systems for heating applications, such as compression combustion engines, can fail due to high current levels and overheating, leading to continuous power delivery and potential damage to heaters and surrounding components.
Innovation Solution
Incorporating a mechanical current interrupting device in series with the solid-state switch and a parallel relay that can shunt current around the switch to reduce heat generation and a control module that selectively closes and opens these components to manage power delivery, along with a current shunt circuit to interrupt power when voltage is outside a desired range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a solid-state switch is used to control power delivery to a heater, then precise control and fast switching are achieved, but the switch fails due to high current levels and overheating
Solution Approach 1:
A current shunt circuit is introduced as an intermediary component connected in parallel with the solid-state switch. This shunt circuit selectively shorts high current around the switch, reducing the current burden on the solid-state switch while maintaining its fast switching capability. The shunt acts as a mediator that protects the switch from excessive current stress.
Solution Approach 2:
The current path is segmented into two parallel pathways: one through the solid-state switch for controlled power delivery, and another through the current shunt circuit for bypassing excess current. This segmentation allows the system to simultaneously achieve precise control and current protection by distributing current flow across multiple paths.
2Duration of action of moving object
If the solid-state switch remains closed to provide continuous power, then heating function is maintained, but the switch overheats and fails
Solution Approach 1:
The control system implements periodic monitoring of the solid-state switch temperature and dynamically adjusts the duty cycle of the switch. When temperature exceeds a threshold, the switch is opened or its duty cycle is reduced, creating periodic on-off cycles that allow thermal dissipation while maintaining overall heating function over extended periods.
Solution Approach 2:
The current shunt circuit serves as a thermal management intermediary by diverting excess current away from the solid-state switch during high-temperature conditions. This reduces the power dissipation and heat generation in the switch, enabling longer continuous operation without overheating failure.
3Device complexity
If no current protection circuit is used, then device complexity is reduced, but arcing occurs and causes component damage
Solution Approach 1:
A mechanically actuated current interrupting device is introduced as a simple intermediary component that physically opens the circuit to interrupt current flow when arcing is detected. This mechanical intervention provides robust arc suppression without requiring complex electronic control circuits, maintaining relatively simple device architecture while effectively preventing arcing damage.
Solution Approach 2:
The system detects arcing conditions (harmful phenomenon) and uses this detection to trigger the mechanical current interrupting device, converting the harmful arcing event into a useful signal that initiates circuit interruption. The harm of arcing detection is transformed into a beneficial protective action that prevents further damage.
4Device complexity
If the solid-state switch is used without parallel current path, then device complexity is minimized, but heat generation damages the switch
Solution Approach 1:
The current path is divided into parallel segments: the primary path through the solid-state switch for controlled power delivery, and a secondary path through the current shunt circuit for heat management. This segmentation creates multiple thermal zones, allowing the shunt path to carry excess current and reduce heat generation in the main switch while maintaining overall system functionality.
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 extends the lifespan of solid-state switches, reduces heat generation, minimizes arcing, and ensures safe power interruption, preventing battery drainage and component damage.
Implementation Method 1
this heater may be a resistive heater, which generates heat in response to electric current
Implementation Method 2
The current shunt circuit is connected in parallel with the load and selectively acts as a short circuit
Implementation Method 3
a mechanical current interrupting device in series with the solid-state switch
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A control system comprises a solid-state switch that is connected in series with a power source and a load and a control module that selectively closes the solid-state switch to provide power to the load, whereby a mechanical current interrupting device that is connected in series with the power source and the solid-state switch, wherein the control module causes the mechanical current interrupting device to mechanically interrupt current flow to the load in response to a voltage of the load being outside of a desired range.