Bidirectional Solid-State Circuit Breaker for High-Power DC Bus
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Solution Overview
Problem
Conventional solid-state circuit breakers based on transistors have low surge current capabilities and are prone to stress-induced failures due to voltage surges when interrupting current, and their transient voltage suppressing components are costly, complex, and unreliable over time.
Innovation Solution
A bidirectional solid-state circuit incorporating forward and reverse switches, a control inductor, and a voltage clamping switch that dynamically manages current flow and voltage clamping during forward and reverse power modes to mitigate voltage surges and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state circuit breakers use transistors to interrupt current flow, then circuit breaking capability is achieved, but voltage surges occur that degrade and damage the semiconductor switches
Solution Approach 1:
The patent introduces a current inductor as an intermediary element between the transistor and the circuit being protected. This inductor acts as a buffer that limits the rate of change of current (di/dt), thereby preventing voltage surges that would otherwise damage the transistor during circuit breaking operations
Solution Approach 2:
The patent places transient voltage suppressing components in parallel with the transistor before fault conditions occur. These components are pre-positioned to provide immediate protection when voltage surges happen during circuit interruption, cushioning the transistor from damage before it can occur
2Reliability
If transient voltage suppressing components are added to protect transistors, then semiconductor device protection is improved, but circuit cost and complexity increase
Solution Approach 1:
The patent designs the circuit so that the current inductor serves multiple functions: it limits di/dt during normal switching operations, provides voltage surge protection during fault conditions, and works in conjunction with the transient voltage suppressing components to enhance overall circuit reliability without requiring separate dedicated protection elements for each function
3Speed
If conventional solid-state circuit breakers interrupt current instantaneously, then circuit breaking speed is improved, but voltage surges are generated that cause stress-induced switch failures
Solution Approach 1:
The current inductor acts as a mediator that allows the transistor to switch rapidly while preventing the instantaneous change in current that causes voltage surges. The inductor's inherent property of opposing changes in current flow smooths the transition, enabling fast breaking without the harmful voltage spikes
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 provides effective circuit breaking and current regulation capabilities while reducing stress on semiconductor devices, enhancing reliability and reducing costs by eliminating the need for transient voltage suppressing components.
Implementation Method 1
a control inductor for controlling current flow during the reverse mode of operation
Implementation Method 2
a voltage clamping switch configured to provide the control inductor in the circuit during the reverse mode of operation and remove the control inductor from the circuit during the forward mode of operation
Data Source
AI summary
An electrical circuit and a method for regulating current and providing a circuit breaker to the electrical circuit. The circuit includes a bidirectional cell including a set of forward switches for power flow during a forward mode of operation and a set of reverse switches for providing reverse power flow during a reverse mode of operation, a control inductor for controlling current flow during the reverse mode of operation, and a voltage clamping switch configured to provide the control inductor in the circuit during the reverse mode of operation and remove the control inductor from the circuit during the forward mode of operation. The circuit is operated in at least the reverse mode of operation.