Power Conversion Device DC Bus Capacitor Segmentation
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Solution Overview
Problem
High-power applications in power electronics lead to increased temperature and reduced lifetime of DC bus capacitors due to higher AC current passing through them, necessitating a solution that addresses both high-power requirements and capacitor protection.
Innovation Solution
A power conversion device with a rectifier module and an inverter module connected via different connection buses and an interconnection bus, decoupling the mutual effects between DC bus capacitors to reduce current passing through them, and utilizing magnetic rings to suppress high-frequency currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power power conversion devices are used to support high-power applications, then the power capability is improved, but the temperature of DC bus capacitors rises and their lifetime shortens
Solution Approach 1:
The invention divides the power conversion device into multiple independent power units (first, second, and third power units), each with its own DC bus capacitor. By segmenting the system, the AC current is distributed across multiple capacitors rather than concentrated in a single capacitor, reducing the current burden on each individual capacitor and thereby extending their operational lifetime while maintaining high power capability.
Solution Approach 2:
The invention combines multiple power units with their respective DC bus capacitors into a unified power conversion system. The capacitors work together in parallel to handle the total AC current, allowing the system to support high-power applications while each capacitor operates within safe current limits, thus resolving the contradiction between power capability and capacitor lifetime.
2Power
If more AC current passes through the DC bus capacitor to support higher power, then the power capability is improved, but the loss of the DC bus capacitor increases and temperature rises
Solution Approach 1:
The total AC current is segmented and distributed across multiple DC bus capacitors in separate power units. Each capacitor handles only a portion of the total current, which reduces the I²R losses in each capacitor. This segmentation allows the system to support higher total power while keeping individual capacitor losses and temperature rises within acceptable limits.
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 configuration reduces the number and volume of DC bus capacitors, increases reliability, and effectively decreases the AC current component, thereby extending the lifespan and improving the performance of the power conversion device.
Implementation Method 1
utilizing magnetic rings to suppress high-frequency currents
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present disclosure provides a power conversion device that includes a power module, and the power module includes a first power unit, a second power unit, a third power unit, a first connection bus, and a second connection bus. The first power unit includes a first DC bus, the second power unit includes a second DC bus, and the third power unit includes a third DC bus. The first connection bus is electrically connected to the first DC bus and the second DC bus, and the second connection bus is electrically connected to the second DC bus and the third DC bus.