Bi-directional DC-DC Converter Voltage Balance Control
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Solution Overview
Problem
Existing UPS systems face inefficiencies and voltage imbalances due to unequal power draw from positive and negative DC busses, leading to issues like losses in efficiency, DC over-voltage, and under-voltage conditions, especially during backup and normal modes of operation.
Innovation Solution
A power converter system with a controller that manages power distribution between multiple DC busses by using switch circuits and transformers to balance power exchange, ensuring equal power draw from both busses through primary and secondary windings, and maintaining constant voltage levels across capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power is drawn unequally from positive and negative DC busses, then the UPS can meet varying load demands, but voltage imbalances and efficiency losses occur
Solution Approach 1:
The controller continuously monitors the voltage levels of both DC busses and dynamically adjusts the power distribution ratio between them. This feedback mechanism ensures that power is drawn more from the bus with higher voltage and less from the bus with lower voltage, maintaining voltage balance and improving efficiency while still meeting varying load demands
Solution Approach 2:
The system dynamically changes the power distribution ratio between positive and negative DC busses based on real-time voltage conditions. The controller adjusts the operating parameters of the DC-DC converter to optimize power flow, transitioning from static to dynamic power management to prevent voltage imbalances
2Productivity
If power distribution between DC busses is unbalanced, then load requirements can be met, but DC over-voltage and under-voltage conditions occur
Solution Approach 1:
The controller uses real-time voltage monitoring to detect imbalances between DC busses and automatically adjusts power distribution to maintain voltage within safe operating ranges, preventing both over-voltage and under-voltage conditions while continuing to meet load requirements
Solution Approach 2:
The system takes preliminary action by continuously monitoring voltage levels and adjusting power distribution before voltage imbalances can lead to over-voltage or under-voltage conditions. This proactive control prevents harmful voltage excursions before they occur
3Ease of operation
If fixed power distribution is used from DC busses, then control is simple, but efficiency losses and voltage imbalances increase
Solution Approach 1:
The system transitions from fixed to dynamic power distribution by implementing real-time voltage monitoring and adaptive control. The controller automatically adjusts the power split ratio between DC busses based on voltage conditions, maintaining simplicity of operation while dramatically improving efficiency through dynamic optimization
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 solution improves efficiency and voltage balance across DC busses, reducing losses and maintaining stable voltage levels, thereby enhancing the overall performance of the UPS system.
Implementation Method 1
the controller is further configured to operate the first switch circuit, the second switch circuit, and the AC switch circuit to provide a first amount of power from a first voltage source providing the first DC voltage to the first capacitor and to provide a second amount of power from the first voltage source to the second capacitor
Data Source
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AI summary
A power converter system is provided and includes a first switch circuit configured to receive a first Direct Current (DC) voltage, the first switch circuit coupled to a second switch circuit having a positive connection and a negative connection to receive a second DC voltage. The power converter system further includes a first capacitor, coupled between the positive connection and a neutral point, a second capacitor, coupled between the negative connection and the neutral point, and an Alternating Current (AC) switch circuit coupled to the first capacitor and to the second capacitor. The power converter system includes a controller configured to maintain a substantially equal voltage level across the first capacitor and the second capacitor, the controller being coupled to the first switch circuit, the second switch circuit, and the AC switch. A method of controlling the power converter system is further disclosed.