Inverter Modularity Control for Power Stack Fault Isolation
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Solution Overview
Problem
Conventional multi-stack solar inverters fail to operate if a fault occurs in one power stack, leading to delayed fault detection, system malfunctions, and excessive maintenance, with no capability for intentional isolation of power stacks or normalization of circuit breaker operations, resulting in poor reliability.
Innovation Solution
A system and method for automatic modularity control of power stacks within a solar inverter, using a controller to monitor and isolate faulty converters while continuously supplying power with remaining healthy converters, performing cyclic start sequencing to extend the life cycle of components and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-stack solar inverter operation is used, then all power stacks must operate together to generate AC power, but the system shuts down completely when any single power stack faults, resulting in loss of power supply continuity
Solution Approach 1:
The inverter system is divided into independent power stack modules, each capable of operating autonomously. The control unit can selectively activate or deactivate individual power stacks based on their operational status, allowing the system to segment functionality and maintain power supply from healthy stacks even when others fault.
Solution Approach 2:
The system dynamically adjusts its operational configuration by detecting faults in real-time and reconfiguring which power stacks remain active. This dynamic adaptation allows the inverter to transition from full-power operation to partial-power operation seamlessly, maintaining continuity rather than shutting down completely.
2Reliability
If fault detection is performed in conventional inverters, then fault detection occurs after system malfunction, but delayed detection causes further system delay and excessive maintenance requirements
Solution Approach 1:
The control unit continuously monitors operational parameters of each power stack before faults manifest as system malfunctions. By detecting anomalies in voltage, current, or operational status early, the system can isolate and flag potential failures before they cause complete stack failure, enabling preventive rather than reactive maintenance.
Solution Approach 2:
The system implements continuous feedback monitoring of each power stack's operational status. The control unit receives real-time data from all stacks and immediately responds to abnormal conditions by isolating faulty stacks, providing rapid feedback that prevents fault propagation and reduces maintenance intervention time.
3Ease of operation
If circuit breakers operate frequently in conventional inverters, then power isolation can be achieved, but lack of normalized operation reduces overall system reliability
Solution Approach 1:
The system implements cyclic start sequencing where circuit breakers are activated and deactivated in a rotating pattern across different power stacks. Instead of always using the same breakers for isolation, the system periodically rotates which breakers perform isolation functions, distributing wear evenly and extending the operational life of all circuit protection components.
Data Source
AI summary
Provided is a method for performing automatic modularity control of an inverter and an inverter that includes DC power sources configured to supply DC power, a plurality of converters to convert direct current power to alternating current power to be supplied to a load, and a controller. The controller performs automatic modularity control of the plurality of converters, by separately controlling the plurality of converters and detecting an operation status thereof and performs fault detection at the plurality of converters at an early stage and isolates a respective converter of the plurality of converters, while continuously supplying power to the load via remaining converters of the plurality of converters. The automatic modularity control further includes early fault detection based continuous monitoring of the current produced by each converter and semiconductor switching feedback and cyclic starting of the inverter to normalize the lifecycle of the circuit breaker.