Phase Rotation Circuit for Single-Phase Micro-Inverter Grid Connection
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Solution Overview
Problem
The existing methods for connecting single-phase micro-inverters in three-phase grid connections are cumbersome and require extensive installation planning due to the need for balanced load distribution across phases, making it inefficient and costly.
Innovation Solution
An apparatus comprising a series of AC power sources with phase rotation circuits that allow single-phase micro-inverters to be connected in a way that automatically balances the three-phase AC current, ensuring equal distribution and simplifying installation processes by rotating phases between micro-inverters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single-phase micro-inverters are connected in a three-phase grid connection using traditional methods, then the system can operate with single-phase inverters, but the installation becomes cumbersome and requires extensive planning to balance the load across phases
Solution Approach 1:
A phase rotation circuit is introduced as an intermediary component between single-phase micro-inverters and the three-phase grid. This circuit rotates the phase of the single-phase output by 120 degrees to create three-phase output, enabling single-phase inverters to connect to three-phase grids without complex installation planning or load balancing requirements
Solution Approach 2:
The phase rotation function is segmented into modular circuits that can be individually coupled to each micro-inverter. Each micro-inverter with its phase rotation circuit operates independently, converting single-phase DC/AC output into rotated three-phase AC output, simplifying the overall system architecture and installation process
2Ease of operation
If traditional three-phase micro-inverters are used, then true three-phase power conversion is achieved, but the electronics requirements are substantially more complex and costly
Solution Approach 1:
Instead of using complex three-phase micro-inverters that directly convert DC to three-phase AC, the invention inverts the approach by using simple single-phase micro-inverters combined with phase rotation circuits. This reversal achieves three-phase power conversion with significantly reduced electronics complexity while maintaining operational efficiency
Data Source
AI summary
An apparatus for power conversion. In one embodiment, the apparatus comprises a plurality of AC power sources, wherein each AC power source in the plurality of AC power sources has a phase rotation circuit coupled to a DC/AC inverter for converting DC input power to AC output power, wherein (i) a first phase rotation circuit has first three phase output terminals coupled to second three phase input terminals of a second phase rotation circuit; (ii) the second phase rotation circuit has second three phase output terminals coupled to third three phase input terminals of a third phase rotation circuit; and (iii) the third phase rotation circuit has third three phase output terminals coupled to either fourth three phase input terminals of a fourth phase rotation circuit or to a commercial power grid.