Wireless Charging Bridge Inverter With DC-Domain Inductors
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Solution Overview
Problem
Conventional bridge inverter designs for wireless charging face challenges such as inefficient performance, high costs, thermal issues, and electromagnetic compatibility problems due to AC losses and square wave production.
Innovation Solution
The proposed bridge inverter circuit includes a reduced component count with only one bridge driver and two MOSFETs, with power inductors placed in the DC domain to minimize AC losses, and an additional LC component in the resonant tank for improved frequency response and EMC, configured to produce half sine waves for each half cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional bridge inverter designs are used, then wireless charging functionality is achieved, but efficiency is reduced due to AC losses
Solution Approach 1:
The patent inverts the conventional bridge inverter configuration by placing power inductors in the DC domain before the inverter stage rather than in the AC domain after the inverter stage. This inversion minimizes AC losses by eliminating eddy current and hysteresis losses in the inductors, as they now operate only with DC current. The resonant tank includes additional LC components to compensate for the changed configuration and maintain proper frequency response.
2Temperature
If conventional bridge inverter designs are used, then wireless charging is enabled, but thermal performance deteriorates
Solution Approach 1:
By inverting the inverter configuration to place power inductors in the DC domain, the patent eliminates the source of thermal problems - AC losses in inductors. Since the inductors now only handle DC current, eddy current and hysteresis losses are minimized, directly improving thermal performance and reducing heat generation in the wireless charging system.
3Object-affected harmful factors
If conventional bridge inverter designs are used, then power transfer is achieved, but electromagnetic compatibility problems occur
Solution Approach 1:
The inverted configuration with power inductors in the DC domain reduces electromagnetic compatibility problems by minimizing high-order harmonic distortion. The additional LC components in the resonant tank further filter harmonics and improve frequency response, resulting in cleaner electromagnetic emissions that are more compatible with surrounding electronic devices.
Solution Approach 2:
The patent changes the operational parameters of the inverter by producing half sine waves for each half cycle instead of conventional square waves. This parameter change in the output waveform reduces harmonic content and improves electromagnetic compatibility, while the additional LC components in the resonant tank support this waveform transformation.
4Ease of manufacture
If component count is reduced, then costs decrease, but performance may be compromised
Solution Approach 1:
The patent extracts unnecessary components from the conventional bridge inverter design, reducing the component count to only one bridge driver and two MOSFETs. By removing redundant components while strategically placing power inductors in the DC domain and adding targeted LC components to the resonant tank, the design achieves lower manufacturing costs without compromising - and actually improving - system performance through reduced losses and better thermal characteristics.
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 configuration enhances efficiency, reduces costs, and improves thermal performance and EMC by minimizing AC losses and high-order harmonic distortion, leading to faster and more reliable wireless charging.
Implementation Method 1
a resonant tank coupled with the first and second transistors and the first and second power inductors
Implementation Method 2
first and second power inductors respectively coupled with the first and second transistors
Data Source
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AI summary
Exemplary embodiments are disclosed of bridge inverters for wireless charging. In an exemplary embodiment, a bridge inverter circuit includes a bridge driver and first and second transistors (e.g., metal-oxide-semiconductor field-effect transistors (MOSFETs), etc.) coupled with the bridge driver. First and second power inductors are respectively coupled with the first and second transistors. A resonant tank is coupled with the first and second transistors and the first and second power inductors. The bridge inverter circuit may include only one bridge driver and only two transistors. The first and second power inductors may be located before the bridge inverter stage such that the first and second power inductors are in the DC domain rather than the AC domain. The resonant tank may include at least one additional inductor-capacitor (LC) component. The bridge inverter circuit may be configured to be operable for producing half sine waves for each half cycle.