Shared-Storage Inverter Isolation for Short-Circuit Backflow Control
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Solution Overview
Problem
In photovoltaic power grid systems, existing inverter apparatuses face challenges in maintaining stable power supply due to intermittent direct current from sources like photovoltaic cells, leading to potential damage from backflow currents during short-circuits and increased hardware costs from individual energy storage systems for each inverter unit.
Innovation Solution
The inverter apparatus incorporates protection units with diodes and power switches that isolate short-circuited units, sharing a single energy storage system among inverter units, and utilizes direct current-direct current converters to prevent surge currents, allowing for zero-voltage turn-on of power switches and flexible bus configurations to manage voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each inverter unit is connected to an individual energy storage system, then the reliability of each inverter unit is improved, but the hardware cost and system complexity increase
Solution Approach 1:
The patent merges multiple individual energy storage systems into a single shared energy storage system that serves all inverter units. The protection units are also combined into a shared configuration where each protection unit can serve multiple inverter units. This merging approach reduces hardware costs and system complexity while maintaining reliability through the shared protection mechanism.
Solution Approach 2:
The protection units are designed with multi-functionality to serve multiple inverter units. Each protection unit can isolate faults for different inverter units and manage energy flow between the shared energy storage system and multiple inverter units, replacing the need for dedicated protection components for each inverter unit.
2Device complexity
If inverter units share a common energy storage system, then hardware cost is reduced, but the risk of backflow current damage during short-circuits increases
Solution Approach 1:
The patent segments the system into independent protection units that can isolate individual inverter units from the shared energy storage system when faults occur. Each protection unit acts as an independent barrier that prevents backflow currents from affecting other inverter units or the energy storage system, enabling safe sharing of the energy storage system.
Solution Approach 2:
The protection units serve as intermediary components between the shared energy storage system and multiple inverter units. These intermediaries include protection circuits with diodes and switches that control energy flow direction, blocking harmful backflow currents while allowing normal bidirectional energy flow during healthy operation.
3Reliability
If protection units use fast-acting switches to isolate faults quickly, then the reliability of the power supply system is improved, but the risk of surge current damage to switches increases
Solution Approach 1:
The protection units perform preliminary actions by pre-charging capacitors and preparing switching elements before isolating faults. The control circuits detect abnormal conditions and activate protection mechanisms in advance, ensuring that switches operate under controlled conditions rather than being subjected to uncontrolled surge currents during fault isolation.
Solution Approach 2:
The patent implements beforehand cushioning by using snubber circuits and controlled switching sequences that dampen surge currents before they can damage the switching elements. Energy dissipation components are positioned to absorb and dissipate surge energy before it reaches the switches, protecting them during rapid fault isolation operations.
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 configuration reduces hardware costs, prevents damage from backflow currents during short-circuits, and maintains power grid stability by isolating faulty units and efficiently managing energy flow, thereby enhancing the reliability and cost-effectiveness of the power supply system.
Implementation Method 1
Any one of the plurality of protection units is configured to: when a voltage at the input terminal of the any protection unit is greater than a voltage at the output terminal of the any protection unit, a path between the input terminal of the any protection unit and the output terminal of the any protection unit is in a forward conducted state; when a voltage at the output terminal of the any protection unit is greater than a voltage at the input terminal of the any protection unit, a path between the input terminal of the protection unit and the output terminal of the protection unit is in a reverse cut-off state
Implementation Method 2
when the control terminal of the any protection unit receives a first trigger signal, a path between the input terminal of the protection unit and the output terminal of the protection unit is in a reverse conducted state
Data Source
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AI summary
This application discloses an inverter apparatus and a power supply system, and pertains to the field of power supply technologies. The inverter apparatus includes a plurality of protection units and a plurality of inverter units. For any protection unit, when a voltage at an output terminal of the protection unit is greater than a voltage at an input terminal of the protection unit, a path between the input terminal of the protection unit and the output terminal of the protection unit is in a forward conducted state; when the voltage at the output terminal of the protection unit is lower than the voltage at the input terminal voltage of the protection unit, the path between the input terminal of the protection unit and the output terminal of the protection unit is in a reverse cut-off state; and when a control terminal of the protection unit receives a first trigger signal, the path between the input terminal of the protection unit and the output terminal of the protection unit is in a reverse conducted state. By using the inverter apparatus, when a short-circuit fault occurs in an inverter unit or a bus in the inverter apparatus, another inverter unit in the inverter apparatus may be isolated, thereby avoiding damage to the inverter unit caused by the short-circuit fault.