Underwater Wireless Charger With Constant Current Distribution
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Solution Overview
Problem
Resonant power conversion systems face challenges in maintaining constant output voltage across a wide range of loads and varying input currents, particularly in applications like underwater telecommunication systems where constant DC current distribution is preferred over voltage distribution, due to high input voltage ranges and component cost issues.
Innovation Solution
The implementation of a DC-DC power supply with an active bridge section operating at a fixed switching frequency, a primary resonant capacitor, and a primary IPT coil, along with a secondary resonant capacitor and IPT coil, where power is transferred wirelessly, and a controller regulates output voltage by controlling the active bridge section's switching, using phase shift modulation to maintain constant output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant DC voltage distribution is used, then output voltage stability is improved, but system robustness against cable impedance and faults deteriorates
Solution Approach 1:
The patent inverts the conventional approach by using constant current distribution instead of constant voltage distribution through the cable, while still achieving stable output voltage through the power supply's current regulation capability. This inversion makes the system more robust against cable impedance variations and faults.
Solution Approach 2:
The patent changes the distribution parameter from voltage to current, using a constant current source that can adapt to varying cable conditions. The power supply maintains stable output voltage by regulating current through the resonant converter, even when input voltage varies widely.
2Adaptability or versatility
If wide input voltage range is accommodated, then adaptability is improved, but component cost and voltage ratings increase
Solution Approach 1:
The patent employs resonant switching with periodic oscillation at the resonant frequency of the LC tank circuit. This periodic action allows the converter to operate efficiently across a wide input voltage range by maintaining resonance, reducing the need for expensive high-voltage rated components.
Solution Approach 2:
The patent replaces traditional voltage-regulation mechanisms with resonant frequency-based current regulation. By using the natural resonance of the LC circuit and controlling the switching frequency, the system achieves wide voltage adaptability without requiring complex voltage regulation components.
3Object-generated harmful factors
If resonant power conversion is used, then electromagnetic interference is reduced, but output voltage regulation across varying loads becomes challenging
Solution Approach 1:
The patent incorporates feedback control through the current-regulated power supply that monitors output conditions and adjusts the resonant converter's operation accordingly. This feedback mechanism maintains stable output voltage across varying loads while preserving the low EMI characteristics of resonant conversion.
Solution Approach 2:
The patent uses dynamic control of the resonant converter's switching frequency and duty cycle to adapt to varying load conditions. The active bridge section dynamically adjusts its operation to maintain optimal resonance and voltage regulation, ensuring stable output despite load variations.
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 solution ensures robustness against cable impedance and faults, maintains constant output voltage across varying loads, and reduces component stress, achieving efficient power transfer with minimal voltage droop and high efficiency.
Implementation Method 1
power is transferred wirelessly between the primary IPT coil and a secondary IPT coil
Implementation Method 2
Resonant power conversion topologies have widely been used in various applications such as DC distribution systems, bi-directional DC-DC converters, and wireless power transfer systems due to their benefits of soft-switching ability, low electromagnetic interference
Data Source
AI summary
An apparatus for inductive power transfer (“IPT”) includes an active bridge section with input terminals that receive power from a constant current source, where the active bridge section operates at a fixed switching frequency, a primary resonant capacitor connected in series with an output terminal of the active bridge section, and a primary IPT coil connected in series with the primary resonant capacitor, where power is transferred wirelessly between the primary IPT coil and a secondary IPT coil, and the secondary IPT coil is connected in series with a secondary resonant capacitor, which is connected in series with an output rectifier section that receives power from the secondary IPT coil and comprising output terminals for connection to a load. The apparatus includes a controller that regulates output voltage to the load, where the controller regulates output voltage to the load by controlling switching of the active bridge section.