Bidirectional Semiconductor Switch Bias Circuit for Blackout Restart
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Solution Overview
Problem
Existing switching apparatuses for connecting and disconnecting appliances to a power grid face issues such as high control power consumption, audible noise, mechanical wear, limited reliability, and the risk of deadlocks during mains blackouts, which lead to increased costs and potential circuit breaker tripping.
Innovation Solution
A bidirectional semiconductor switch with an ultra-low power bias supply circuit and additional features like randomization, metal oxide semiconductor field effect transistors, and watchdog circuits to ensure reliable operation during unlimited mains interruptions, reducing power consumption and preventing synchronous inrush currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical relay is used for switching, then the switching function is achieved, but audible noise and mechanical wear occur leading to limited lifetime and higher cost
Solution Approach 1:
The patent replaces the mechanical relay with a bidirectional semiconductor switch controlled by gate signals. The semiconductor switch uses electrical fields rather than mechanical movement to achieve switching, eliminating audible noise and mechanical wear while maintaining reliable switching functionality between mains phases and neutral.
2Object-generated harmful factors
If a simple semiconductor switch replaces the mechanical relay, then mechanical wear is eliminated, but dead-lock situations occur after mains blackout and depletion of energy storage element
Solution Approach 1:
The patent incorporates an energy storage element (capacitor) that is pre-charged during normal operation. After a mains blackout, this pre-stored energy enables the semiconductor switch to remain controllable and recover from dead-lock situations without requiring immediate external power, ensuring reliable operation restoration.
Solution Approach 2:
The patent introduces a floating auxiliary voltage generated through a bias supply circuit as an intermediary power source. This auxiliary voltage, stored in a capacitor and regulated by a Zener diode, mediates between the mains power and the semiconductor switch control, enabling the switch to maintain functionality during power interruptions.
3Ease of operation
If frequent recharging of energy storage is required, then the switching function can be maintained, but audible noise and mechanical wear increase
Solution Approach 1:
The patent replaces the mechanical relay that requires frequent recharging with a semiconductor switch that can be controlled by low-power gate signals. The semiconductor switch maintains its switching function through electrical control rather than mechanical actuation, eliminating noise and wear even during frequent recharging cycles.
4Productivity
If all connected devices start simultaneously after mains voltage return, then power restoration is achieved, but synchronous inrush current trips circuit breakers
Solution Approach 1:
The patent incorporates a randomizer that introduces random delays in the startup sequence of devices after mains voltage restoration. This preliminary anti-action prevents synchronous inrush current by ensuring devices start at different times, avoiding circuit breaker tripping while still achieving rapid power restoration.
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 solution enables reliable operation of appliances during extended power outages with reduced energy storage needs, fewer recharging cycles, and smaller, cheaper energy storage components, while preventing circuit breaker tripping and mechanical wear.
Implementation Method 1
the bias supply circuit may comprise a serial connection of the at least one capacitor and a zener diode adapted to limit the supply voltage derived from the power grid
Implementation Method 2
a diode for rectifying the limited supply voltage to obtain the floating auxiliary voltage
Implementation Method 3
the semiconductor switch may comprise at least two metal oxide semiconductor field effect transistors or at least two insulated gate bipolar transistors
Data Source
AI summary
The present invention relates to a bidirectional semiconductor switch (M1, M2) with extremely low control power consumption and a bootstrap circuit which allows reliable start of operation of the switch and the hosting device after unlimited duration of mains interruptions. Intelligent control options are provided by operating from a small energy storage and no extra means are required to recover from a depleted energy storage condition. The absence of audible noise and mechanical wear also enables more frequent recharging cycles and allows smaller and thus cheaper energy storage components.