Multilevel IPT Converter for Fast EV Charging
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Solution Overview
Problem
Conventional inductive power transfer (IPT) systems using IGBT-based H-bridge converters face limitations in switching capability and produce undesirable harmonics at higher frequencies, making them unsuitable for high-power applications like fast electric vehicle charging, which requires lower switching losses and harmonic distortions.
Innovation Solution
A multilevel IPT converter with a first switching means producing a time-varying input power signal and a second switching means modifying it to enable wireless power transfer, allowing the second switching means to operate at higher frequencies without excessive losses, using MOSFETs and IGBTs, and employing selective harmonic elimination to reduce specific harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If IGBT-based H-bridge converters are used for high-frequency operation, then switching frequency can be increased, but switching losses and harmonic distortions become excessive
Solution Approach 1:
The patent divides the H-bridge converter into two separate switching means: a first switching means (using MOSFETs) that operates at high frequency to generate the input power signal, and a second switching means (using IGBTs) that operates at lower frequency to modify the signal. This segmentation allows each component to operate in its optimal frequency range, enabling high-frequency operation while keeping IGBT switching losses acceptable.
2Speed
If IGBT-based H-bridge converters are used for high-frequency operation, then switching frequency can be increased, but harmonic distortions increase
Solution Approach 1:
The patent segments the conversion process into two stages with different switching means. The first switching means generates a high-frequency signal with controlled harmonics, and the second switching means modifies this signal to reduce harmonic content. This segmentation enables high-frequency operation while managing harmonic distortions through the coordinated action of both switching stages.
3Device complexity
If conventional IGBT-based converters are used, then device simplicity is maintained, but dv/dt and di/dt performance deteriorates at higher frequencies
Solution Approach 1:
The patent divides the converter into two switching means with different semiconductor device types. The first switching means uses MOSFETs which have superior high-frequency switching capability and dv/dt performance, while the second switching means uses IGBTs for power modification. This segmentation allows the system to achieve high-frequency operation with improved switching capability while maintaining a relatively simple overall structure.
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 converter design achieves lower switching losses and harmonic distortions, enabling efficient high-frequency operation suitable for high-power applications like fast electric vehicle charging, with improved efficiency and reduced thermal loading on the grid.
Implementation Method 1
a resonant circuit adapted to provide wireless power transfer
Data Source
AI summary
An inductive power transfer (IPT) converter has a first switching means adapted to produce a time varying input power signal comprising a substantially unipolar stepped waveform, and a second switching means adapted to modify the time varying input power signal provided by the first switching means to produce a modified input power signal. The converter is coupled to a resonant circuit to receive the modified input signal.