Fault Clearing Circuitry for Power Inverters
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Solution Overview
Problem
Existing power inverters often require overdimensioning to effectively clear faults like short circuits, which increases technical resources and is not sufficient for opening distribution fuses or circuit breakers, as they can only supply a current that is 2-3 times the nominal current.
Innovation Solution
A fault clearing circuitry that includes an electrical energy storage component, a controllable switch, and a control circuit to monitor for faults and inject a time-limited higher current pulse into the electrical line, capable of releasing circuit breakers or clearing fuses by discharging stored energy through the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inverter is over dimensioned to have a higher fault clearing capability, then the fault clearing capability is improved, but more technical resources are required
Solution Approach 1:
The patent applies preliminary action by pre-charging an electrical energy storage component (capacitor) before a fault occurs. The capacitor is charged to a voltage higher than the nominal operating voltage during normal operation. When a fault is detected, this pre-stored energy is immediately discharged through a controllable switch to generate a high current pulse for fault clearing, eliminating the need for continuous high power capability and avoiding overdimensioning.
2Reliability
If the inverter supplies a higher electric current for fault clearing, then the fault clearing capability is improved, but the current is not sufficient for opening distribution fuses or circuit breakers
Solution Approach 1:
The patent employs periodic action by delivering the high current pulse in a controlled time-limited manner. The controllable switch (such as an IGBT or MOSFET) is activated for a specific duration to discharge the capacitor, creating a high-amplitude current pulse that lasts only long enough to trigger the circuit breaker or fuse. This pulsed approach concentrates energy delivery into a brief interval, achieving sufficient peak current without requiring continuous high power capability.
Solution Approach 2:
The patent applies parameter changes by dynamically altering the voltage and current parameters of the energy storage component. The capacitor is charged to a voltage parameter higher than nominal operating voltage (e.g., 1.2 to 1.5 times the nominal voltage). When fault clearing is needed, this voltage parameter is maintained while a high current is drawn for a limited time, effectively changing the operating point to deliver the required fault clearing current without permanently overdimensioning the system.
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
This solution allows for efficient fault clearing without the need for overdimensioning, enabling quick and controlled activation of circuit breakers or fuses, thereby enhancing the fault clearing capability of power inverters.
Implementation Method 1
an electrical energy storage; at least one controllable switch connectable between the electrical energy storage and at least one electric line
Data Source
AI summary
A fault clearing circuitry provided for connecting to at least one electrical line transmitting power includes: an electrical energy storage; at least one controllable switch connectable between the electrical energy storage and at least one electric line; and a control circuit for monitoring the at least one electric line for a fault and to close the at least one controllable switch if a fault is detected. The electrical energy storage stores an amount of electrical energy dimensioned to be sufficient for releasing one or more circuit breakers or clearing one or more fuses in the at least one electrical line in order to clear the fault. The control circuit closes the at least one controllable switch if a fault is detected such that a discharging of the electrical energy stored in the electrical energy storage is incurred injecting a current pulse in the at least one electrical line.