Bidirectional DC/DC Converter Cell with Feedback Capability
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Solution Overview
Problem
Existing DC/DC converter circuits lack a universal topology for bidirectional connection with feedback capability, particularly for DC voltage sources with variable terminal voltage connected to a DC voltage sink with constant terminal voltage, which is essential for efficient energy transport and storage.
Innovation Solution
A DC/DC converter cell with three input connections and two output connections, featuring multiple converter stages with symmetrical series circuits and capacitors, allowing bidirectional energy flow and reducing the stress on power switches, enabling efficient voltage matching and ripple reduction through suitable control of power switches and optional coil coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC/DC converter circuit uses conventional topology for voltage matching, then voltage conversion is achieved, but bidirectional energy transport capability is lost
Solution Approach 1:
The patent applies universality by designing a DC/DC converter circuit with a symmetric H-bridge topology that can operate in both forward and reverse directions. The same circuit components (switches Q1-Q4, capacitors C1-C2, inductor L1) serve dual functions: converting voltage from low to high in forward mode, and from high to low in reverse mode, enabling bidirectional energy transport without requiring separate converter circuits.
2Loss of energy
If the DC bus system voltage level is chosen considerably higher than DC voltage source output, then line losses are reduced, but voltage matching becomes more difficult
Solution Approach 1:
The patent employs dimensionality change by introducing a multi-level voltage structure with intermediate voltage levels between the input DC voltage source and the high-voltage DC bus. The H-bridge circuit generates multiple voltage levels (positive DC voltage, negative DC voltage, and zero voltage) through different switch configurations, creating a stepped voltage transition that reduces stress on power switches while achieving the required voltage multiplication.
3Device complexity
If photovoltaic systems with variable output voltage are connected directly to constant voltage DC sinks, then system simplicity is maintained, but voltage matching and energy efficiency deteriorate
Solution Approach 1:
The patent applies dynamics by implementing a controllable power electronic converter that dynamically adjusts its operation to match the variable output characteristics of photovoltaic systems with the constant voltage requirements of DC sinks. The control unit monitors the input voltage variations and dynamically switches the H-bridge components to maintain optimal power transfer, enabling the system to adapt to changing photovoltaic output while maintaining efficient energy transport.
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 proposed solution enables efficient bidirectional energy transport, reduces the stress on power switches, and minimizes the need for inductive components, achieving stable voltage conversion and reduced ripple in output currents, suitable for applications with significant voltage differences between DC voltage sources and sinks.
Implementation Method 1
L1 an inductor, whose first terminal is connected to the center point and whose second terminal forms the fourth output connection
Implementation Method 2
C1 and C2 two capacitors, whose first terminals are connected to the center point and whose second terminals are connected to each other
Data Source
AI summary
A DC/DC converter circuit having feedback capability with a first converter device whose two inputs form the inputs of the DC/DC converter circuit and can be connected to a DC voltage source. The DC/DC converter circuit has a DC voltage-coupled second converter device whose outputs form the outputs of the DC/DC converter circuit and can be connected to a DC voltage sink, wherein the second converter device is in the form of a DC/DC converter cell or of a DC/DC converter cell arrangement having two DC/DC converter cells.