LC Pulse Forming Network for DC-DC Power Converters
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Solution Overview
Problem
Existing DC-DC power converters using transmission lines as energy storage devices face inefficiencies due to the need for large numbers of discrete components in Rayleigh networks, leading to increased footprint, cost, and labor costs, as well as cross-talk issues when multiple converters are used, especially at high frequencies.
Innovation Solution
The use of a pulse forming network with 5 LC segments, where inductor and capacitor values are derived from the Fourier transform of the transmission line impedance/admittance function, to simulate the transmission line characteristics more accurately than traditional Rayleigh networks, reducing the number of components needed and improving impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Rayleigh network with many LC segments is used to simulate a transmission line, then the transmission line characteristics are accurately simulated, but the number of components, footprint, cost, and assembly labor increase significantly
Solution Approach 1:
The patent applies parameter changes by using non-uniform LC segment values derived from Fourier transform of the transmission line impedance/admittance function. Instead of using identical L and C values for all segments as in traditional Rayleigh networks, each segment's L and C values are specifically calculated to match the frequency-dependent characteristics of the transmission line, achieving accurate simulation with fewer segments.
Solution Approach 2:
The patent uses segmentation by dividing the transmission line into a finite number of discrete LC segments. Each segment represents a portion of the distributed transmission line, and by carefully selecting the number and values of these segments based on Fourier analysis, the patent achieves accurate transmission line simulation with a manageable number of components.
2Device complexity
If a Rayleigh network with fewer LC segments is used, then the component count and footprint are reduced, but the transmission line simulation accuracy deteriorates and cross-talk occurs between multiple converters
Solution Approach 1:
The patent resolves this contradiction by changing the parameters of the LC segments from uniform values to frequency-dependent values calculated via Fourier transform. This allows each segment to contribute optimally to the transmission line simulation across the frequency range, maintaining accuracy even with fewer segments.
Solution Approach 2:
The patent applies preliminary action by pre-calculating the optimal L and C values for each segment using Fourier transform of the desired transmission line impedance/admittance function before implementation. This preliminary design step ensures that the segmented network will accurately simulate the transmission line characteristics without requiring excessive segmentation.
3Power
If traditional Rayleigh networks are used at high frequencies, then voltage boosting is achieved, but unnecessary losses and cross-talk occur due to poor pole and zero convergence
Solution Approach 1:
The patent changes the parameters of the LC segments to match the frequency-dependent impedance/admittance characteristics of the transmission line. By using Fourier transform to determine optimal L and C values, the network's poles and zeros converge to the correct frequencies, minimizing energy losses and eliminating cross-talk between multiple converters operating at high frequencies.
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 allows for a more compact, efficient, and cost-effective DC-DC power converter with improved impedance matching, capable of accurately simulating an ideal transmission line with fewer components, reducing unnecessary losses and cross-talk, and enabling efficient voltage boosting.
Implementation Method 1
an ideal transmission line has an infinite number of resonances. These resonances are identified as poles or zeros on an impedance versus frequency graph
Implementation Method 2
The pulse forming network impedance is thus much closer to that of an ideal transmission line than a Rayleigh network
Data Source
AI summary
A DC-DC power converter having a power source, a load, and a transmission line terminated at one end. A first switch is electrically connected between the power source and a second end of the transmission line and movable between an open and a closed position. A second switch is electrically connected between the second end of the transmission line and the load and is movable between an open and a closed position. A switch control circuit switches the first and second switches between their respective open and closed positions. A pulse forming network forms the transmission line to store the charge in the transmission line.