Virtual Inverter Controller for Nanogrid Branch Protection
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Solution Overview
Problem
In nanogrids operating in island mode, the response speed of miniature circuit breakers (MCBs) is slower than the internal protection speed of inverters, causing the entire system to stop when a malfunction occurs, as prior art fails to ensure timely tripping of protectors before inverter protection is initiated.
Innovation Solution
A virtual inverter controller is introduced, equipped with sensors to detect voltage, current, and frequency parameters, and a control component that simulates the protection function of inverters, sending trip signals to protectors to trip before inverter protection is activated, thereby ensuring quicker isolation of malfunctioning branches and maintaining nanogrid operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MCB protectors are used in nanogrid branches, then the system has basic protection capability, but the response speed is slower than inverter protection causing whole system shutdown
Solution Approach 1:
The virtual inverter controller is equipped with protection functions that activate before the actual inverter protection is needed. The controller detects faults and triggers MCB tripping in advance, ensuring the protector acts faster than the inverter's internal protection mechanism would otherwise respond.
Solution Approach 2:
The virtual inverter controller replicates the protection algorithms and functions of the actual inverter in software. By copying the inverter's protection logic into the virtual controller, the system achieves fast MCB tripping that mimics ideal inverter protection response without being limited by the physical inverter's response time.
2Reliability
If protectors are equipped on all branches, then comprehensive protection is achieved, but the complexity of the system increases
Solution Approach 1:
The virtual inverter controller serves multiple functions: it controls the inverter operation and simultaneously provides protection functions for the MCB. By integrating these functions into a single controller, the system achieves comprehensive branch protection without proportionally increasing system complexity.
Solution Approach 2:
The protection functions are merged into the virtual inverter controller rather than being separate dedicated protection devices. This consolidation allows the controller to manage both normal operation and protection tasks, reducing the number of separate components needed while maintaining comprehensive protection coverage.
Data Source
AI summary
A nanogrid and a virtual inverter controller for the nanogrid are disclosed. The nanogrid includes at least one parallel branch, and at least one branch is equipped with a protector. At least one of the protectors is equipped with one virtual inverter controller. The virtual inverter controller includes a sensor component configured to detect at least one characteristic parameter on the branch, and a control component affecting the electrical connection state of the corresponding protector of the virtual inverter controller according to the characteristic parameter.