Inverter DC/DC Converter Diode Coupling for PV Adaptability
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Solution Overview
Problem
Inverter manufacturers face complexity in providing a variety of models to accommodate different generator constellations in photovoltaic systems, as existing solutions require multiple configurations for various connection options and DC/DC converter assignments, making it challenging to achieve flexible operation.
Innovation Solution
An inverter design that couples DC/DC converters via a diode, allowing for independent potential adjustment and automatic adaptation to different PV generator constellations, enabling operation as either a module inverter or string inverter without external bridges, using actively controllable diodes to reduce voltage drop and maintain blocking characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple inverter models are provided for different generator constellations, then adaptability to various PV system configurations is improved, but device complexity and manufacturing variety increases
Solution Approach 1:
The patent implements a universal inverter design where DC/DC converters can dynamically switch between series and parallel connection modes through controllable switches. This allows a single inverter model to accommodate multiple generator constellations (module-level, string-level, or hybrid configurations) without requiring separate hardware models, thereby resolving the contradiction between adaptability and device complexity
Solution Approach 2:
The inverter employs dynamic reconfiguration capability where the connection topology of DC/DC converters can be changed in real-time based on the connected generator configuration. Controllable switches enable the system to adapt its internal structure dynamically, allowing the same hardware to serve multiple purposes across different application scenarios
2Loss of substance
If DC/DC converters are connected in parallel without diodes, then material effort is reduced, but voltage drop and forward losses increase
Solution Approach 1:
The patent introduces controllable diodes as intermediary elements in the parallel connection of DC/DC converters. These diodes act as mediators that enable current flow in the forward direction with minimal voltage drop while maintaining blocking characteristics in the reverse direction. The controllable nature of these diodes allows them to be activated only when needed, reducing overall energy losses while still providing the necessary protection and functionality
3Adaptability or versatility
If DC/DC converters are connected in series via external bridges, then generator constellation flexibility is improved, but device complexity and material effort increase
Solution Approach 1:
The patent merges the function of external series-connection bridges with the internal structure of the inverter by integrating controllable switches directly into the DC/DC converter modules. This consolidation eliminates the need for separate external bridge components, as the inverter's internal switching network can create series connections between converters when required, thereby achieving series connectivity without additional material or complexity
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
The inverter can flexibly operate in various generator configurations, reducing material effort and enabling efficient power conversion with independent operation of DC/DC converters, whether connected in series or independently, thus simplifying the design and operation of photovoltaic systems.
Implementation Method 1
The diode is connected with its terminals to one of the inputs of each of the two DC/DC converters
Implementation Method 2
The switch is used to reduce the voltage drop across the device when a current is flowing in the direction of flow, so that the forward losses across the diode are reduced without losing the blocking characteristics
Implementation Method 3
Inverters are used in energy supply systems, such as photovoltaic systems, to convert direct current into alternating current
Implementation Method 4
Such a DC/DC converter converts the DC voltage supplied to its input into a higher DC voltage in this application, which is then provided to the inverter bridge
Data Source
AI summary
The disclosure relates to an inverter with at least one inverter bridge and at least two galvanically isolating DC/DC converters, outputs of the DC/DC converters being connected in parallel with one another and being connected to inputs of the inverter bridge. At least two of the DC/DC converters are intercoupled on the input side via a diode, such that the diode is connected with its terminals to one of the inputs of the two direct voltage converters in each case. The disclosure also relates to a use for such an inverter.