Non-Isolated DC-DC Converter Topology for Wide-Range Constant Voltage
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Solution Overview
Problem
Conventional power conversion devices using LLC resonant converter circuits face difficulties in maintaining a constant output voltage when the voltage range is wide, often requiring a separate constant-voltage circuit for initial control before voltage adjustment.
Innovation Solution
A power conversion device comprising multiple non-isolated DC-DC converter circuits with bidirectional elements, where inputs are connected in parallel and outputs in series, allowing for constant voltage control through PWM control signals, eliminating the need for a high-frequency transformer and simplifying circuit design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an LLC resonant converter circuit is used for voltage conversion, then voltage raising or lowering can be achieved, but it becomes difficult to maintain constant output voltage across a wide voltage range
Solution Approach 1:
The power conversion device is divided into multiple non-isolated DC-DC converter circuits (first, second, third, and fourth circuits) that operate in parallel. Each converter circuit handles a portion of the total power conversion task, enabling the system to cover a wide voltage range while maintaining stable output voltage through coordinated operation of the segmented units.
2Reliability
If a constant-voltage circuit is added upstream of the LLC resonant converter circuit, then constant voltage control can be achieved, but the device complexity increases
Solution Approach 1:
The non-isolated DC-DC converter circuits perform multiple functions simultaneously: they provide voltage conversion, maintain constant output voltage across wide ranges, and eliminate the need for separate constant-voltage circuits. The bidirectional elements within these converters enable both power flow directions and voltage regulation, making the converter circuits universal components that replace what would traditionally require separate dedicated circuits.
Solution Approach 2:
The patent merges the voltage conversion function and constant voltage control function into a single integrated system using multiple non-isolated DC-DC converter circuits. By connecting these circuits in parallel with bidirectional elements, the system combines what would traditionally be separate constant-voltage circuits and voltage conversion stages into one unified structure, reducing overall device complexity.
3Power
If traditional LLC resonant converter circuits are used, then voltage conversion is achieved, but additional constant-voltage circuits are required for wide voltage ranges
Solution Approach 1:
The non-isolated DC-DC converter circuits with bidirectional elements serve as universal power conversion units that can operate in both power flow directions and provide voltage regulation. These multi-functional circuits replace the need for separate constant-voltage circuits, achieving both voltage conversion and constant voltage control through the same integrated components.
Data Source
AI summary
According to one embodiment, a power conversion device includes a plurality of non-isolated DC-DC converter circuits each including a bidirectional element, wherein inputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel, and outputs of the plurality of non-isolated DC-DC converter circuits are connected in series. According to another embodiment, a power conversion device includes a plurality of non-isolated DC-DC converter circuits each including a bidirectional element, wherein inputs of the plurality of non-isolated DC-DC converter circuits are connected in series, and outputs of the plurality of non-isolated DC-DC converter circuits are connected in parallel.