Semiconductor Circuit Breaker Dual Overvoltage Protection
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Solution Overview
Problem
Semiconductor circuit breakers face challenges in protecting against overvoltages, particularly in the 'ON' and 'STANDBY' states, with existing varistor protection devices being insufficient in preventing damage from high overvoltages and excessive energy discharge.
Innovation Solution
A dual protection system comprising a varistor and a transient voltage suppression diode, connected in parallel with the main semiconductor switch, is implemented, along with an electronic controller to manage the switches and ensure protection against overvoltages in all operating states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a varistor protection device is connected in parallel with the main semiconductor switch, then protection against high one-time overvoltage is provided, but the varistor remains vulnerable to damage from excessive overvoltage energy in the STANDBY state
Solution Approach 1:
A switching device is introduced as an intermediary between the varistor and the circuit, controlling when the varistor is connected to the circuit. The switch disconnects the varistor from the circuit during normal operation and reconnects it only when needed for protection, preventing the varistor from being exposed to excessive overvoltage energy that would damage it.
Solution Approach 2:
The protection circuit transitions from a static configuration to a dynamic one where the varistor's connection to the circuit is controlled by a switching device. This allows the protection system to adapt its configuration based on operational state, connecting the varistor only when protection is needed while maintaining it disconnected during normal operation to prevent damage.
2Reliability
If the main semiconductor switch is protected against overvoltages, then component reliability is improved, but the circuit complexity increases due to additional protection devices
Solution Approach 1:
The protection system is designed to serve multiple functions: the varistor provides overvoltage clamping, the switching device controls connection timing, and the system operates in both ON and STANDBY states. This multi-functionality justifies the added complexity by providing comprehensive protection across different operational modes rather than requiring separate protection systems for each state.
Solution Approach 2:
The protection system combines multiple components (varistor, switching device, control circuitry) into an integrated system that works together. The varistor and switching device are combined to create a controlled protection mechanism, and the protection system is merged with the existing circuit breaker architecture to provide unified protection rather than separate isolated systems.
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
The dual protection system effectively safeguards the semiconductor components against overvoltages, ensuring complete protection in both 'ON' and 'STANDBY' states, and includes a thyristor switch for robust and automatic operation.
Implementation Method 1
a first protection device (32) comprising a varistor and a first switch (34) connected in series with the first protection device
Implementation Method 2
a second protection system, connected in parallel with said first protection system and said main semiconductor switch, the second protection system comprising a second protection device (40) comprising a transient voltage suppression diode
Data Source
AI summary
An electrical circuit breaker with overvoltage protection includes a pair of connection terminals, a main semiconductor switch including at least one semiconductor component and a pair of separable contacts forming a disconnector connected in series with the main semiconductor switch between the connection terminals. The electrical circuit breaker also includes a first protection system connected in parallel with the main switch, the first protection system including a first protection device including a varistor and a first switch connected in series with the first protection device. The electrical circuit breaker further includes a second protection system, connected in parallel with the first protection system and said the main semiconductor switch, the second protection system including a second protection device including a transient voltage suppression diode.