Solid-State Circuit Breaker Load Detection for Safe Switching
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Solution Overview
Problem
Current solid-state circuit breakers cannot determine the type of load they are connected to, leading to potential safety risks such as reverse intake powering, bus-tie switch applications, and improper handling of capacitive and inductive loads, which result in surge or inrush currents.
Innovation Solution
A solid-state circuit breaker system that measures current and voltage at its intake and load terminals, uses a pulse voltage to charge the load, and analyzes the discharge patterns to identify the load type, allowing for appropriate closing strategies to avoid safety risks and manage current surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If solid-state circuit breaker is used to replace mechanical circuit breaker, then closing and opening speed is much faster and control is more precise, but the ability to determine load type is lost leading to safety risks
Solution Approach 1:
The patent applies preliminary action by performing load type detection before the circuit breaker closes. The control unit detects whether the load is capacitive or inductive in advance, and only closes the circuit breaker when the load type is confirmed to be safe (resistive or unknown). This prevents surge currents and inrush currents from damaging the solid-state switch while maintaining the fast response characteristics of solid-state circuit breakers.
2Productivity
If circuit breaker closes without load type detection, then operation is simpler and faster, but surge currents for capacitive loads and inrush currents for inductive loads can damage the solid-state switch
Solution Approach 1:
The control unit performs load type detection before closing the circuit breaker by measuring current and voltage characteristics. This preliminary detection identifies capacitive loads (which would cause surge currents) and inductive loads (which would cause inrush currents), preventing the circuit breaker from closing under conditions that would damage the solid-state switch.
Solution Approach 2:
The patent implements feedback by continuously monitoring current and voltage at the terminals of the solid-state switch. The control unit uses this feedback information to determine load type and make intelligent closing decisions, adjusting the closing strategy based on real-time electrical characteristics to avoid harmful currents.
3Measurement precision
If load type detection is implemented by measuring current and voltage, then load type can be determined accurately, but device complexity increases
Solution Approach 1:
The patent applies universality by using the existing current and voltage measurement capabilities of the solid-state circuit breaker for dual purposes: normal operation control and load type detection. The control unit utilizes the same sensors and measurement circuits that are already part of the solid-state circuit breaker design, eliminating the need for separate dedicated detection hardware and reducing overall system complexity.
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
Enables precise determination of load type, preventing damage by avoiding surge currents for capacitive loads and inrush currents for inductive loads, and ensuring safe and efficient operation.
Implementation Method 1
a solid-state switch is connected between a power intake terminal of the solid-state circuit breaker and a load terminal of the solid-state circuit breaker
Implementation Method 2
a first measurement unit and a second measurement unit are respectively connected to the first terminal and the second terminal to measure a current and/or voltage
Data Source
AI summary
The present disclosure relates to a solid-state circuit breaker and a control method therefor. The solid-state circuit breaker comprises a solid-state switch, a first measurement unit, a second measurement unit, a control unit, and a driving unit. The first measurement unit is used to measure the current and/or voltage at a first terminal of the solid-state switch. The second measurement unit is used to measure the current and/or voltage at a second terminal of the solid-state switch. The control unit is used to: when the solid-state switch is turned off, determine whether the first terminal is charged; determine whether the second terminal is charged; control the driving unit to input a pulse voltage to a control terminal of the solid-state switch; and after the pulse duration has ended, determine the type of load.