DC-DC Converter AC-Link Impedance Synthesis Without Magnetics
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Solution Overview
Problem
Existing DC:DC power converters using passive inductors or transformers face limitations such as size, energy storage issues, fixed inductance, undesirable frequency response, and complexity, which affect their performance and efficiency in aerospace applications.
Innovation Solution
A DC:DC power converter with an active impedance synthesizer, comprising an active bridge circuit controlled by a switching controller, capable of emulating various impedances, including inductances, to address these limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If passive inductors or transformers are used in DC:DC power converters, then voltage transformation and power transfer are achieved, but size and weight increase
Solution Approach 1:
The patent replaces passive magnetic components (inductors and transformers) with an active impedance synthesizer comprising power electronic switches, capacitors, and control circuitry. This substitution eliminates bulky magnetic cores and windings, significantly reducing the converter's size and weight while maintaining voltage transformation and power transfer capabilities through active switching and synthesis of equivalent impedance.
Solution Approach 2:
The patent changes the fundamental operating principle from passive magnetic energy storage to active electronic impedance synthesis. By using controllable power switches and energy storage capacitors with switching control, the system dynamically synthesizes the required impedance characteristics, enabling voltage transformation without heavy magnetic components.
2Power
If passive inductors are used in DC:DC power converters, then inductance is provided for power transfer, but inductance value is fixed and cannot be adjusted
Solution Approach 1:
The patent implements dynamic impedance control by using power electronic switches that can be controlled in real-time. The impedance synthesizer can dynamically adjust its equivalent inductance, resistance, and capacitance values by changing switching frequencies, duty cycles, and topological configurations, allowing the system to adapt to varying load conditions and optimize power transfer efficiency under different operating scenarios.
Solution Approach 2:
The patent enables continuous adjustment of impedance parameters through electronic control. By modifying switching frequencies, duty ratios, and control signals to the power switches, the system can vary the synthesized impedance values to match optimal operating points for different power levels and load conditions, providing adaptability that passive components cannot achieve.
3Power
If passive inductors are used in DC:DC power converters, then energy storage is provided, but energy storage capacity is limited and fixed
Solution Approach 1:
The patent replaces passive inductor-based energy storage with active energy management using capacitors and controlled switching. The system uses energy storage capacitors combined with power electronic switches to transfer and regulate energy, eliminating the need for large inductors while achieving superior energy storage efficiency and flexibility through electronic control of charge and discharge cycles.
4Power
If passive inductors or transformers are used in DC:DC power converters, then voltage transformation is achieved, but frequency response is undesirable and limited
Solution Approach 1:
The patent achieves superior frequency response by using active switching control instead of passive magnetic components. The impedance synthesizer can respond dynamically to frequency changes by adjusting switching frequencies and duty cycles in real-time, enabling the system to maintain optimal voltage transformation across a wide frequency range and adapt to transient conditions that passive components cannot handle effectively.
Data Source
AI summary
A DC:DC power converter 10, an electrical power system 100 comprising a DC:DC power converter 10, and a method 500 of operating an electrical power system 100 are described. The DC:DC power converter 10 comprises: a DC:AC converter circuit 11; an AC:DC converter circuit 12; an AC link 13 that connects an AC side of the DC:AC converter circuit 11 to an AC side of the AC:DC converter circuit 12 and has an impedance synthesizer 14 connected therein, the impedance synthesizer 14 comprising an active bridge circuit 140; and a switching controller 15 configured to control a switching operation of a plurality of power semiconductor switches 141L,H, 142L,H of the active bridge circuit 140 and thereby control an output voltage of the impedance synthesizer 14 and an impedance of the AC link 13.