Active Current Surge Limiter for Voltage Sag Protection
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Solution Overview
Problem
Existing surge protection technologies, such as transient voltage surge suppressors (TVSS), are ineffective in limiting current surges that occur during voltage sags, which are more frequent and damaging to electrical equipment than voltage surges, and inrush current limiting circuits do not provide protection during normal operation.
Innovation Solution
Active current surge limiters are introduced, comprising a current limiter connected between a power supply and a load, a disturbance sensor to monitor power supply conditions, and an activator that activates the current limiter when disturbances are detected, using microcontrollers, semiconductor switches, and electromechanical relays to manage current flow and limit surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If transient voltage surge suppressors (TVSS) are used to clamp voltage levels, then voltage surge protection is improved, but current surge protection during voltage sags is not provided
Solution Approach 1:
The active current surge limiter integrates multiple protection functions into a single device: it can detect voltage sags, activate current limiting during sags, and also provide voltage surge clamping. This multi-functional approach resolves the contradiction by providing both voltage surge protection and current surge protection during voltage sags through one unified system.
Solution Approach 2:
The system dynamically adjusts its protection mode based on real-time power supply conditions. A disturbance sensor continuously monitors the power supply, and when a voltage sag is detected, the system automatically activates the current limiter. This dynamic response enables the system to provide current surge protection during voltage sags while maintaining voltage surge protection capabilities.
2Object-generated harmful factors
If inrush current limiting circuits with NTC thermistors are used during startup, then startup current surge is reduced, but protection during normal operation is not provided
Solution Approach 1:
The active current surge limiter is pre-configured and ready to operate during normal conditions. The disturbance sensor continuously monitors power supply conditions, and the system is prepared to activate current limiting immediately when a voltage sag is detected. This preliminary preparation ensures both startup protection and ongoing protection during normal operation.
Solution Approach 2:
Unlike NTC thermistors that only provide protection during startup, the active current surge limiter maintains continuous monitoring and protection capability throughout normal operation. The disturbance sensor continuously watches for voltage sags, and the current limiter remains ready to activate, providing uninterrupted protection across all operational phases.
3Productivity
If bypass switches are used to remove current limiters after startup, then normal operation current is improved, but vulnerability to transients increases
Solution Approach 1:
The system employs a disturbance sensor that continuously provides feedback about power supply conditions. When a voltage sag or transient is detected, the sensor triggers the activator to close the bypass switch and activate the current limiter. This feedback mechanism ensures the system responds dynamically to transients while maintaining optimal current flow during normal operation.
Solution Approach 2:
The active current surge limiter prepares to counteract transients before they can cause damage. The disturbance sensor continuously monitors for incoming voltage sags, and when detected, the system preemptively activates the current limiter to protect against the upcoming transient event, rather than waiting for damage to occur.
Data Source
AI summary
Active current surge limiters (100) and methods of use are disclosed. One exemplary system, among others, comprises a current limiter (140), including an interface configured to be connected between a power supply (110) and a load (120); a disturbance sensor (150), configured to monitor the power supply for a disturbance during operation of the load; and an activator (160), configured to receive a control signal (215) from the disturbance sensor (150) and to activate the current limiter (140) based on the control signal.