Balanced Capacitor Converter Topology for Passive Voltage Balance
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Solution Overview
Problem
Power converters face inefficiencies and complexity when dealing with high input voltages, particularly in solar inverter systems, due to the need for balancing capacitors and managing auxiliary power supplies, which often disrupt the energy balance across capacitors and require complex control mechanisms.
Innovation Solution
A power diverting topology that uses a switching circuit with diodes and switches to draw power from balanced capacitors without disrupting their energy balance, allowing for open-loop control and efficient operation by selectively connecting capacitors to an output voltage, thereby preserving voltage balance across capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an auxiliary power supply is added to draw power from capacitors, then auxiliary power is provided, but the energy balance across capacitors is disrupted
Solution Approach 1:
The auxiliary power supply is designed to automatically detect voltage imbalances across the capacitors and draw power preferentially from capacitors with higher voltage, thereby self-regulating to maintain capacitor balance without external control intervention
Solution Approach 2:
The system continuously monitors the voltage across each capacitor and uses this feedback information to control the switching of power draw, ensuring that power is extracted in a manner that maintains or restores voltage balance among capacitors
2Productivity
If complex control mechanisms are used to manage auxiliary power supply, then power conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The auxiliary power supply incorporates automatic balance-maintaining functionality that operates without complex external control, using inherent voltage differences across capacitors to drive the balancing process and reduce control system complexity
Solution Approach 2:
The capacitor balance maintenance function is integrated into the auxiliary power supply circuitry itself, combining two functions (power extraction and balance maintenance) into a single system rather than requiring separate control mechanisms
Data Source
AI summary
A power device may have at least two capacitors in series with each other and in parallel with a DC power source. The power device may have at least a first converter that has at least a controller configured to balance a voltage of the at least two capacitors. The power device may have at least a second converter connected to the at least two capacitors. The second converter may have at least three input conductors, each connected to a terminal of the at least two capacitors. The second converter may have at least two output conductors. The second converter may have at least a switching circuit between the at least three input conductors and at least two output conductors. The second converter may have at least a controller configured to operate the switching circuit. The second converter may passively preserve the voltage balance between the at least two capacitors.