Power Conversion Circuit Resonant Compensation for DCR Loss
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Solution Overview
Problem
Existing power conversion circuits for lithium batteries face inefficiencies due to direct current resistance (DCR) and parasitic capacitance losses, which are difficult to reduce without increasing costs and size, thereby limiting the overall conversion efficiency.
Innovation Solution
A power conversion circuit design incorporating a first switch branch, a second switch branch, a third switch branch, and a filter branch with a filter inductor and capacitor, where the filter capacitor is connected in parallel with the load, reducing current and voltage amplitudes to minimize DCR and parasitic capacitance losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the DCR is reduced to reduce DCR loss, then the conversion efficiency is improved, but the price and size of the inductor increase
Solution Approach 1:
The patent introduces a resonant capacitor as an intermediary component to form a resonant circuit with the inductor. This resonant circuit creates a reactive impedance that compensates for the DCR loss, allowing the use of an inductor with higher DCR without sacrificing overall conversion efficiency, thereby avoiding the need for larger, more expensive inductors
Solution Approach 2:
The patent changes the operating parameters by introducing resonance at a specific frequency. By tuning the resonant capacitor to create resonance with the inductor, the circuit transforms the inductor's impedance characteristics, converting the problematic DCR into a manageable parameter that no longer dominates the loss profile
2Loss of energy
If the parasitic capacitance at switch node LX is reduced to reduce loss, then the conversion efficiency is improved, but the size of the power transistor switch must be reduced which increases internal resistance
Solution Approach 1:
The patent converts the harmful parasitic capacitance loss into a beneficial resonant effect. By intentionally designing the resonant capacitor to work in conjunction with the parasitic capacitance and inductor, the previously harmful reactive power loss is transformed into a useful resonant condition that improves overall circuit efficiency and power factor
3Device complexity
If the power conversion circuit uses traditional topology with two switches, then the structure is simple, but the conversion efficiency is limited by DCR and parasitic capacitance losses
Solution Approach 1:
The patent merges the functions of power conversion and power factor correction into a single integrated circuit topology. By combining the resonant capacitor with the existing inductor and switches, the circuit simultaneously achieves efficient power conversion and resonant compensation, eliminating the need for separate correction circuits and maintaining structural simplicity while improving efficiency
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
The proposed design reduces direct current resistance and parasitic capacitance losses, thereby enhancing the conversion efficiency of the power conversion circuit.
Implementation Method 1
the filter branch includes a filter inductor and a filter capacitor that are connected in series
Data Source
AI summary
A power conversion circuit includes a first switch branch, a second switch branch, a third switch branch, a filter branch, and a first capacitor. A first terminal of the first capacitor is connected to a power source through the first switch branch, and a second terminal of the first capacitor is grounded through the second switch branch. The filter branch includes a filter inductor and a filter capacitor. A first terminal of the filter inductor is connected to the first terminal of the first capacitor, and a second terminal of the filter inductor is connected to a first terminal of the filter capacitor. A second terminal of the filter capacitor is grounded, and the filter capacitor is connected in parallel with the load. The third switch branch is connected between the second terminal of the first capacitor and the second terminal of the filter inductor.