PV Inverter Switching Unit for Dynamic DC Input Allocation
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Solution Overview
Problem
Existing inverter systems for photovoltaic systems face challenges in efficiently and flexibly integrating multiple direct-voltage units with varying properties and performance parameters, leading to complex system planning, high costs, and inefficient use of DC inputs.
Innovation Solution
An inverter system with a predetermined number of DC-to-DC converters and a switching unit that dynamically assigns connections between DC inputs and direct-voltage units based on current power variables, allowing flexible and efficient use of DC inputs for different units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple DC-to-DC converters are used to support multiple direct-voltage units, then the system can integrate more units with different properties, but the device complexity and cost increase
Solution Approach 1:
The patent applies universality by designing a single inverter unit that can handle multiple direct-voltage units with different properties through a common DC link. The inverter unit is configured to accept DC inputs from various sources (PV modules, batteries, capacitors) and convert them to AC output, eliminating the need for separate inverters for each unit type. This multi-functional approach reduces system complexity while maintaining adaptability to integrate diverse direct-voltage units.
2Reliability
If dedicated DC-to-DC converters are assigned to each direct-voltage unit, then each unit can operate optimally, but the cost and device complexity increase
Solution Approach 1:
The patent merges multiple DC-to-DC conversion functions into a single inverter unit that interfaces with a common DC link. Instead of having separate DC-to-DC converters for each direct-voltage unit, the inverter unit consolidates the conversion functionality, receiving DC power from multiple units through the shared DC link and converting it to AC output. This merging approach maintains optimal operation of each unit while significantly reducing the total number of converters needed.
3Adaptability or versatility
If the inverter system is designed to accommodate various direct-voltage units, then flexibility is improved, but the ease of manufacture decreases
Solution Approach 1:
The inverter unit is designed as a universal platform that can accommodate various direct-voltage units through standardized interfaces and a common DC link architecture. This universal design allows the same inverter unit to work with different unit types (PV modules, batteries, capacitors) without requiring custom manufacturing for each configuration, thereby improving ease of manufacture while maintaining flexibility.
4Adaptability or versatility
If multiple DC inputs are provided for different unit types, then adaptability is improved, but the inefficient use of DC inputs occurs
Solution Approach 1:
The patent implements dynamic allocation of DC inputs through a common DC link architecture that allows flexible connection and disconnection of direct-voltage units based on operational needs. The system can dynamically adjust which units are connected to the DC link and how power is distributed, ensuring that DC inputs are efficiently utilized according to actual power generation and consumption requirements rather than being statically assigned.
Data Source
AI summary
The present invention relates to an inverter system (INV) for a photovoltaic system and to a method for operating the inverter system (INV). The inverter system (INV) comprises an inverter unit (WE), ), to which a predetermined number of DC-to-DC converters (B1, . . . , B4) is connected upstream via an intermediate circuit (ZK). The DC inputs (DC1, . . . , DC4) of the inverter system (INV) are formed by the DC-to-DC converters (B1, . . . , B4), which predetermines the number and properties of the DC inputs (DC1, . . . , DC4). The DC inputs (DC1, . . . , DC4) are connected to different direct-voltage units (PV1, PV2, BAT, EC, GE, VB), in particular PV units, energy storage units, etc. A switching unit (SE), which comprises inputs (E1, . . . , E6) for connecting the direct-voltage units (PV1, PV2, BAT, EC, GE, VB), is connected to the DC inputs (DC1, . . . , DC4). The switching unit (SE) is thus arranged between the DC-to-DC converters (B1, . . . , B4) forming the DC inputs (DC1, . . . , DC4) and the direct-voltage units (PV1, PV2, BAT, EC, GE, VB) which are connectable to the switching unit (SE). The different direct-voltage units (PV1, PV2, BAT, EC, GE, VB) connected to the inputs (E1, . . . , E6) are identified (101, 102), and for each direct-voltage unit (PV1, PV2, BAT, EC, GE, VB) connected to an input (E1, . . . , E6) of the switching unit (SE) a current value of at least one power variable is determined (103). The determined current value of the at least one power variable is then compared with at least one predetermined threshold value (104). Depending on a respective comparison result, the switching unit (SE) then establishes a connection between the respectively connected direct-voltage unit (PV1, PV2, BAT, EC, GE, VB) and at least one suitable DC input (DC1, . . . , DC4) and/or adapts the connection (105).