Surge Control Circuit with Bypass Switch and Absorption Element
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Solution Overview
Problem
Existing surge absorption circuits increase the required withstanding voltage of protected electrical equipment, necessitating a solution to reduce the voltage applied during current surges.
Innovation Solution
A surge control circuit with an absorption circuit and a bypass switch, controlled by a detection system that switches current flow between the absorption circuit and a switch group based on preset current and rate of change values, utilizing components like varistors and insulated gate bipolar transistors to manage surge currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nonlinear resistance element is connected in parallel to both ends of the protected equipment, then the surge current can be discharged to protect the equipment, but the voltage reaching the rated discharge current is considerably higher than the rated voltage, thereby increasing the requirement of withstanding voltage in design of the equipment
Solution Approach 1:
The surge protection function is divided into two segments: a switch group that handles normal current flow and a nonlinear resistance element that handles surge current. The switch group is connected in parallel to both ends of the absorption circuit, allowing current to bypass the absorption element during normal operation and only engage it during surge events, thereby segmenting the functional responsibilities and reducing voltage requirements for the protected equipment
Solution Approach 2:
A control circuit acts as an intermediary between the surge detection system and the switch group. It detects surge conditions and controls the switching elements to connect or disconnect the switch group based on preset current values and rate of change, thereby mediating the response to surge events and optimizing the protection mechanism
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
Effectively reduces the voltage applied to protected equipment during surges, lowering the design requirements for withstanding voltage and minimizing equipment damage.
Implementation Method 1
the absorption element of the surge absorption circuit is a nonlinear resistor. When a withstanding voltage of the nonlinear resistor is lower than the maximum continuous operating voltage, a resistance value of the nonlinear resistor is great, and current flowing through the nonlinear resistor is very small. When the withstanding voltage of the nonlinear resistor exceeds the maximum continuous operating voltage, the resistance value of the nonlinear resistor in a protection circuit is dropped rapidly with increase of the withstanding voltage, and current flowing through the nonlinear resistor is increased rapidly, such that the surge current is discharged
Data Source
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AI summary
Disclosed is a surge control circuit, including: an absorption circuit including an absorption element and a bypass switch which are connected in series, a switch group connected in parallel to both ends of the absorption circuit and a first control circuit electrically connected to the switch group and bypass switch respectively. Normally, the first control circuit controls the switch group and the bypass switch to turn on simultaneously, makes the current flow through the switch group; when detecting the current is greater than or equal to the first preset current value, or the current increase rate is greater than or equal to the preset current rate of change, the first control circuit controls the switch group to turn off, makes the current flow through the absorption circuit; when detecting the current is less than the second preset current value, the first control circuit controls the bypass switch to turn off.