DC-DC Converter Intermediate Circuit Voltage Control
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Solution Overview
Problem
Existing DC-DC converters for solar installations have limited adjustability of output voltage, making it difficult to set individual DC mains voltages independently, which restricts the operational range.
Innovation Solution
A DC voltage converter system with multiple DC-DC converters coupled via an intermediate circuit capacitor, where the intermediate circuit potentials can be set independently of the common reference potential, allowing for adjustable intermediate circuit voltages without altering DC line voltages or currents, enabling broader range adjustments of individual DC mains voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the DC-DC converters are coupled via an intermediate circuit capacitor connected between a first intermediate circuit potential and a second intermediate circuit potential (different from common reference potential), then switching losses are reduced, but the output voltage depends on power flow and DC grid voltages of solar modules, limiting adjustability
Solution Approach 1:
The patent introduces an intermediate circuit converter as a mediator between the intermediate circuit capacitor and the DC networks. This converter, with its own DC-DC conversion capability, acts as an intermediary that can independently adjust the intermediate circuit potentials (first and second potentials) relative to the common reference potential. This mediation allows the main DC-DC converters to operate with reduced switching losses while the intermediate circuit converter handles the voltage adjustment function, thereby resolving the contradiction between energy efficiency and adaptability.
2Device complexity
If the intermediate circuit potentials are fixed relative to common reference potential, then the system structure is simpler, but the individual DC network voltages cannot be adjusted independently over a wider range
Solution Approach 1:
The patent implements dynamic adjustability of the intermediate circuit potentials through the intermediate circuit converter. The first and second intermediate circuit potentials can be dynamically adjusted independently of the DC network voltages and currents by controlling the intermediate circuit converter. This dynamic capability enables the system to adapt to different operating conditions and adjust individual DC network voltages over a wider range, while the converter's control system manages the complexity to maintain operational simplicity.
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 allows for independent adjustment of individual DC mains voltages over a larger range, enhancing the flexibility and efficiency of the DC voltage converter system.
Implementation Method 1
the DC-DC converters are coupled via a first intermediate circuit capacitor connected between a first intermediate circuit potential and a second intermediate circuit potential
Implementation Method 2
an intermediate circuit converter via which the first intermediate circuit potential and/or the second intermediate circuit potential can be adjusted independently of the DC network voltages and the DC network currents
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a DC-to-DC converter for coupling at least three DC voltage networks, the converter comprising at least three DC-DC regulators (101, 102, 301), each regulator having a DC voltage mains connection (X11, X12, X21) that is supplied with a DC voltage network voltage (UG1, UG2, UA1) related to a common reference potential (X5), a respective DC voltage network current (IG1, IG2, IA1) flowing through each connection. The DC-DC regulators (101, 102, 301) are coupled via a first DC link capacitor (C1) which is connected between a first DC link potential (X3) and a second DC link potential (X4), the first DC link potential (X3) and the second DC link potential (X4) being different from the common reference potential (X5). The DC-to-DC converter also comprises a DC link regulator (401), via which the first DC link potential (X3) and/or the second DC link potential (X4) can be set independently of the DC voltage network voltages (UG1, UG2, UA1) and the DC voltage network currents (IG1, IG2, IA1).