Power Converter Ripple Reduction via Segmented DC-DC Topology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DC uninterruptible power supplies with positive-side and negative-side capacitors face voltage imbalance due to ripple components in three-phase AC input, leading to shortened capacitor lifespans and increased replacement frequency.
Innovation Solution
A power converter design that includes a series-connected input-side converter circuit and parallel-connected output-side converter circuits, where the first output-side converter circuit reduces ripple components flowing into the positive-side capacitor, and the second output-side converter circuit reduces ripple components flowing into the negative-side capacitor, using adjusted currents to cancel out ripple components, thereby mitigating the need for high capacitance and extending capacitor lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitance of the first capacitor and the second capacitor is increased to reduce voltage imbalance caused by ripple components, then the output voltage imbalance is reduced, but the component lifespan is shortened
Solution Approach 1:
The patent divides the single DC/DC converter into two separate DC/DC converters (first and second output-side converter circuits), each handling one capacitor. This segmentation allows independent control of ripple current for each capacitor, enabling lifespan extension without compromising voltage balance. Each converter can be optimized to minimize ripple current in its associated capacitor while maintaining overall system balance.
Solution Approach 2:
The patent changes the control parameters of the DC/DC converters to minimize ripple current in the capacitors. By adjusting the switching duty ratios and control signals, the system optimizes the current waveforms to reduce the RMS value of ripple current flowing through each capacitor, thereby extending lifespan while maintaining voltage balance through active control.
2Reliability
If the capacitance of the first capacitor and the second capacitor is increased to reduce voltage imbalance, then the voltage balance is improved, but the device size increases
Solution Approach 1:
By segmenting the converter into two independent DC/DC converter circuits, each capacitor can be sized optimally for its specific function rather than requiring oversized capacitors to handle all ripple current. This allows using smaller capacitance values while maintaining voltage balance through coordinated control of both converter circuits.
Solution Approach 2:
The patent uses active control of converter parameters to reduce ripple current, which allows the use of smaller capacitors with lower capacitance values. The control system dynamically adjusts switching parameters to minimize the ripple component, enabling compact capacitor design without sacrificing voltage stability.
3Reliability
If the capacitance of the first capacitor and the second capacitor is increased to reduce voltage imbalance, then the output voltage balance is improved, but the manufacturing cost increases
Solution Approach 1:
The patent segments the system into two independently controlled DC/DC converter circuits, which allows for more efficient use of smaller, less expensive capacitors. Rather than requiring one or two large-capacitance electrolytic capacitors, the system can use smaller capacitors with longer lifespans, reducing both component cost and replacement maintenance costs.
Solution Approach 2:
By reducing the stress on capacitors through the dual-converter architecture and ripple minimization control, the patent enables the use of capacitors with longer inherent lifespans (such as non-electrolytic types) instead of relying on oversized electrolytic capacitors that would require frequent replacement, thereby reducing long-term manufacturing and maintenance costs.
Data Source
AI summary
A power converter includes: an input-side converter including a positive-side capacitor arranged between a positive terminal and a neutral terminal as well as a negative-side capacitor arranged between a negative terminal and the neutral terminal; a first converter connected to the positive terminal and the neutral terminal; and a second converter, an input side thereof being connected to the negative terminal and the neutral terminal, with the input side also being connected in series to the first converter, and the output side thereof being connected in parallel to the first converter.