Transformer-Based Capacitor Voltage Balancing for High-Voltage Systems
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Solution Overview
Problem
Existing methods for voltage balancing in series-connected capacitors, such as those used in high voltage electric vehicle systems, result in constant current flow through symmetry resistors or semiconductors even when voltage is evenly distributed, leading to energy consumption, heat generation, and increased component size and cost due to unnecessary balancing current.
Innovation Solution
A method utilizing a transformer with coupled windings and semiconductor switches to balance voltages across electrolytic capacitors by controlled discharging and charging processes, ensuring equal voltage distribution without continuous current flow when balanced, and using a central control unit for asynchronous switching to minimize losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetry resistors or semiconductors are used for voltage balancing in series-connected capacitors, then voltage distribution is equalized, but constant current flow occurs even when balancing is unnecessary, leading to energy consumption and heat generation
Solution Approach 1:
The patent transforms the static, continuous balancing approach into a dynamic, conditional approach. The balancing circuit is activated only when voltage imbalance is detected through monitoring, and deactivated when voltages are equal. This dynamic switching eliminates unnecessary continuous current flow while maintaining reliable voltage balancing when needed.
Solution Approach 2:
The system monitors its own voltage distribution state and automatically activates or deactivates the balancing circuit accordingly. When voltages are balanced, the system requires no external intervention or continuous power consumption. When imbalance occurs, the system self-corrects by activating the balancing circuit, then deactivates it once balanced, creating a self-regulating mechanism.
2Reliability
If symmetry resistors or semiconductors are used for voltage balancing, then voltage distribution is equalized, but heat is generated requiring dissipation and larger component design
Solution Approach 1:
The patent implements dynamic control where the balancing circuit operates intermittently rather than continuously. By monitoring voltage levels and activating balancing only when imbalance is detected, the system minimizes heat generation while maintaining effective voltage equalization. The circuit switches off when balanced, eliminating continuous heat dissipation requirements.
3Reliability
If continuous balancing current flows through symmetry resistors or semiconductors, then voltage balancing is maintained, but component size and cost increase due to heat loss requirements
Solution Approach 1:
The patent employs dynamic switching control where the balancing circuit is activated only when voltage imbalance is detected and deactivated when voltages are equal. This on-demand operation allows components to be sized for intermittent rather than continuous operation, reducing component size and system complexity while maintaining reliable voltage balancing functionality.
Solution Approach 2:
The system autonomously monitors its voltage state and activates balancing only when necessary. This self-regulating behavior eliminates the need for oversized components designed to handle continuous worst-case scenarios, allowing for more compact and cost-effective component selection while ensuring voltage balancing reliability.
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 approach efficiently balances voltages across capacitors, reducing energy losses and heat generation, and minimizing component size and cost by only activating switches when necessary, thus improving the operational safety and efficiency of high voltage systems.
Implementation Method 1
a transformer with a first and a second winding, wherein the first and the second winding have the same number of turns N... by which a current flow is produced which causes a discharging of a capacitor arranged in the first circuit across the first winding and induces a current flow in the second winding
Data Source
AI summary
A method for voltage balancing of series connected capacitors, wherein a voltage in an intermediate circuit of an electric circuit can be easily and safely balanced between a plurality of series connected capacitors and thus these components are operated safely in terms of their voltage strength. This problem is solved in that the voltage balancing is accomplished in that, in a first step of the method, an at least partial discharging of a first or a second capacitor occurs across a first or second winding of a transformer, while thanks to the action of the transformer a current is induced in a second step of the method in the second or first winding which charges the second or first capacitor as a charging current.