Cascaded Inverter Power Architecture for Lower Cable Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current three-phase grid-connected photovoltaic inverters face issues with high current and voltage requirements, leading to larger cable diameters and increased costs due to high input and output currents, which result in inefficiencies and higher losses.
Innovation Solution
A power system design that cascades output voltages of power modules or DC-to-AC units to reduce current flow, allowing for the use of lower wire diameter cables and reducing costs by minimizing the number of cables needed between power modules or DC-to-AC units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If centralized or decentralized inverters are used with high conversion power, then power generation capacity is improved, but input and output currents increase leading to larger cable diameters and higher costs
Solution Approach 1:
The inverter system is divided into multiple distributed inverters, each handling a portion of the total power conversion. This segmentation allows each unit to operate at optimized current levels while collectively achieving high power generation capacity, thereby avoiding the need for excessively large diameter cables that would be required by a single centralized inverter.
Solution Approach 2:
The patent introduces a cascading voltage architecture that adds a voltage dimension to the power transmission. By cascading multiple DC-to-AC units with increasing voltage levels, the system transmits power at higher voltages and lower currents, effectively moving the solution from a single-dimension (current-based) to a multi-dimension (voltage-current) approach, which reduces cable diameter requirements.
2Quantity of substance
If distributed inverters operate at low conversion power with high input voltage, then cable diameter is reduced, but conversion efficiency decreases due to larger currents
Solution Approach 1:
The patent dynamically adjusts operating parameters by cascading DC-to-AC units with different voltage levels. This parameter change strategy allows the system to operate at optimized voltage-current combinations that reduce both cable diameter and energy losses simultaneously, overcoming the trade-off between these two parameters.
Solution Approach 2:
By introducing a cascading voltage structure with multiple stages operating at different voltage levels, the system adds a voltage dimension to power transmission. This enables operation at higher voltages with lower currents, simultaneously achieving reduced cable diameter and improved conversion efficiency by minimizing I²R losses.
3Quantity of substance
If high input voltage is used in distributed inverters, then cable specifications are reduced, but system complexity increases due to multiple units required
Solution Approach 1:
The cascading DC-to-AC unit architecture serves multiple functions simultaneously: it steps up voltage levels, reduces current transmission requirements, provides modular scalability, and enables flexible system configuration. This multi-functionality reduces overall system complexity despite the presence of multiple units, as they work together in a standardized cascading pattern.
Data Source
AI summary
A power system is disclosed. Output terminals of a power supply or a DC-to-DC unit are cascaded to increase an output voltage, so as to reduce a current between the power supply or the DC-to-DC unit and the DC-to-AC unit, and resolve cost and loss problems of the cable from the power supply or the DC-to-DC unit to the DC-to-AC unit. In addition, according to the power system provided in the embodiments of this application, a quantity of cables from the power supply or the DC-to-DC unit to the DC-to-AC unit may be further reduced by cascading output terminals of the power supply or the DC-to-DC unit and cascading inputs of the DC-to-AC unit, thereby reducing system costs. In addition, in the power system provided in the embodiments of this application, cascaded input and isolated output of the DC-to-AC unit can reduce a specification of a power conversion device.