Common Boost Converter for Photovoltaic Inverters
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Solution Overview
Problem
Conventional step-up converters in inverter circuits for photovoltaic generators suffer from efficiency losses, increased weight, volume, and cost due to additional components and asymmetrical voltage levels, which are exacerbated by fluctuating DC voltages from photovoltaic generators.
Innovation Solution
A circuit arrangement using a common step-up converter with a series circuit of inductors and rectifier elements for two DC sources, connected through a common switching element, reduces energy storage and reactive power, minimizing losses and enhancing efficiency by allowing static series or parallel operation of DC sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional step-up converter with separate inductors and diodes for each DC source is used, then the circuit can handle fluctuating DC voltages from photovoltaic generators, but losses in the step-up converter increase and overall efficiency decreases
Solution Approach 1:
The patent merges two separate step-up converter paths into a single common step-up converter. The first and second DC sources are connected to a shared inductor and shared diode, eliminating redundant components. This consolidation reduces the number of switching operations and energy storage requirements, thereby reducing converter losses while maintaining the ability to handle fluctuating voltages from both photovoltaic sources.
Solution Approach 2:
The common inductor and common diode in the step-up converter serve dual functions for both DC sources. The single inductor L1 and single diode D1 handle power conversion for both the first DC source (from first photovoltaic generator) and the second DC source (from second photovoltaic generator), making the components universal rather than dedicated to a single source. This multi-functionality reduces component count and associated losses.
2Adaptability or versatility
If a step-up converter with multiple inductors and diodes is used to handle multiple DC sources, then the circuit can process power from multiple photovoltaic generators, but the weight, volume, and cost increase
Solution Approach 1:
The patent combines multiple power processing paths into a single integrated step-up converter structure. Instead of having separate inductors (L1a, L1b) and diodes (D1a, D1b) for each DC source, the invention uses shared inductor L1 and shared diode D1 that serve both the first DC source and second DC source. This merging dramatically reduces the total component mass while maintaining the capability to process power from multiple photovoltaic generators.
3Adaptability or versatility
If a step-up converter with multiple inductors and diodes is used to handle multiple DC sources, then the circuit can process power from multiple photovoltaic generators, but the volume and cost increase
Solution Approach 1:
The patent merges multiple power processing functions into a compact single inductor-single diode step-up converter configuration. The common inductor L1 and common diode D1 replace what would traditionally require separate inductors and diodes for each DC source, significantly reducing the converter's physical footprint while maintaining full functionality for processing power from both the first and second photovoltaic generators.
4Stability of the object's composition
If a step-up converter with separate components for each DC source is used, then the circuit can maintain symmetrical voltage levels, but the device complexity and number of components increase
Solution Approach 1:
The patent simplifies the converter structure by merging the power processing paths of two DC sources into a single step-up converter with one inductor and one diode. This consolidation reduces device complexity and component count while the control unit maintains symmetrical voltage levels through coordinated switching of the first and second power switches, proving that simplicity and voltage symmetry can coexist.
Solution Approach 2:
The patent employs dynamic control through a control unit that coordinates the switching operations of both power switches. This dynamic control mechanism adjusts the switching timing and duration to maintain symmetrical voltage levels at the outputs, compensating for the simplified hardware structure. The dynamic coordination enables voltage symmetry without requiring complex static circuit arrangements.
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 significantly reduces losses in the step-up converter, increases overall efficiency, reduces cooling requirements, and minimizes semiconductor component load, achieving a broader input voltage range with fewer components.
Implementation Method 1
When the circuit breaker 14 is closed, current flows from the photovoltaic generator 10 into the inductor 12 and is temporarily stored there. If the circuit breaker 14 is then opened, the current flows from the photovoltaic generator 10 via the diode 16 into the intermediate circuit capacitor 18, with the energy previously stored in the inductor 12 also being released to the intermediate circuit capacitor 18.
Implementation Method 2
If the circuit breaker 14 is then opened, the current flows from the photovoltaic generator 10 via the diode 16 into the intermediate circuit capacitor 18
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An inverter circuit includes a first and a second DC source (10a, 10b) for providing a DC voltage; a common boost converter (12-16) for boosting both the DC voltage provided by the first DC source (10a) and the DC voltage provided by the second DC source (10b); an intermediate circuit capacitor (18) connected between the outputs of the common boost converter (12-16); and an inverter (20) for converting the DC voltage provided by the intermediate circuit capacitor (18) into an AC voltage.