Parallel Power Converter Restart After Short-Circuit Elimination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wind power generation and photovoltaic systems with multiple power conversion devices connected in parallel, a short circuit in one device can cause excessive sneak currents in other devices, leading to system-wide shutdowns even if they have not experienced a short circuit.
Innovation Solution
The implementation of a power conversion device with a short circuit elimination determination unit that assesses whether a short circuit has been resolved, allowing unaffected devices to be promptly restarted even when one device experiences a short circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power conversion devices with short-circuit current interruption units are used, then short-circuit current can be interrupted, but other unaffected devices are also stopped due to excessive sneak currents
Solution Approach 1:
The invention introduces a determination unit that locally assesses whether a short circuit has occurred in each specific power conversion device. This allows individual devices to be identified and isolated without affecting the operation of other unaffected devices in the parallel system, thereby resolving the contradiction between reliable short-circuit interruption and maintaining system productivity.
Solution Approach 2:
The invention segments the control logic by introducing a determination unit that independently evaluates each power conversion device's status. This segmentation enables selective operation where only affected devices are stopped while unaffected devices continue to operate, solving the problem of system-wide shutdowns.
2Reliability
If short-circuit current interruption units operate in response to excessive sneak currents, then short-circuit current is interrupted, but current routes are disconnected in unaffected devices
Solution Approach 1:
The determination unit performs preliminary assessment before stopping a device by first determining whether a short circuit has actually occurred. This preliminary action prevents unnecessary disconnection of current routes in unaffected devices, allowing them to continue operating and be restarted without interruption.
Solution Approach 2:
The determination unit provides feedback information about the actual short circuit status to the control system. This feedback mechanism ensures that only devices with confirmed short circuits are stopped, while unaffected devices maintain their operation and can be promptly restarted.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Even when one power conversion device among a plurality of power conversion devices connected in parallel experiences a short circuit, the other power conversion devices having experienced no short circuit can be promptly restarted. Each power conversion device includes: a short circuit occurrence determination unit (33) configured to determine, on the basis of a current value at an output terminal (3a), whether or not a short circuit has occurred; a short circuit elimination determination unit (34) configured to determine, on the basis of a current value and a voltage value at the output terminal, whether or not the short circuit has been eliminated; and a current interruption unit (32) configured to, on the basis of determination by the short circuit occurrence determination unit (33) and determination by the short circuit elimination determination unit (34), interrupt current that flows from a power conversion unit to the output terminal or cancel the interruption.