Medium-Voltage Wireless Charging Without a Step-Down Transformer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dynamic wireless power transfer (DWPT) systems for electric vehicles face challenges in efficiently charging vehicles in motion due to variable load profiles and grid impact, particularly in low-voltage distribution networks, and existing solutions do not effectively address the need for high-power, fast charging while minimizing stress on the AC grid.
Innovation Solution
A modular DWPT system with a grid-interface module that converts three-phase AC voltage to high-frequency AC power, using a modular multilevel converter (MMC) topology to directly connect to a medium-voltage AC grid without a step-down transformer, and incorporates energy storage to reshape the load profile and reduce grid stress, enabling efficient power transfer to multiple vehicles simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional low-voltage DWPT system uses a step-down transformer to access the power system, then the system can operate with standard voltage levels, but the system becomes costly and bulky due to the required transformer
Solution Approach 1:
The patent removes the step-down transformer from the system by directly connecting the DWPT system to the medium-voltage power grid. This extraction eliminates the bulky and costly transformer component while maintaining voltage level compatibility through direct medium-voltage operation.
Solution Approach 2:
The patent changes the operating voltage parameter from conventional low-voltage (480V) to medium-voltage levels, allowing the system to operate directly on the power grid without transformation. This parameter change eliminates the need for transformers and reduces system cost and size.
2Adaptability or versatility
If the DWPT system operates with variable load profile based on vehicle speed, then the system adapts to different charging scenarios, but the system causes considerable stress to the AC grid with large harmonic components
Solution Approach 1:
The patent implements a pre-charging phase before the main charging phase, allowing the system to gradually establish connection and reduce sudden load impacts on the grid. This preliminary action smooths the load profile and reduces harmonic distortion.
Solution Approach 2:
The patent uses periodic charging phases with alternating active and inactive periods, allowing the grid to recover between charging cycles. This periodic operation reduces continuous stress and harmonic distortion on the power system.
3Productivity
If the system uses high-power DWPT to increase power transfer capability for short charging windows, then the charging speed increases, but the grid impact and harmonic distortion increase
Solution Approach 1:
The patent implements a pre-charging phase that prepares the system before high-power transfer, allowing gradual power increase and reducing sudden grid impacts while maintaining high charging capability during the main charging phase.
Solution Approach 2:
The patent uses dynamic power adjustment during charging, varying the power level based on real-time grid conditions and charging requirements. This dynamic control maintains high productivity while adapting to grid constraints and reducing stress.
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 modular system provides reliable, high-power wireless charging with reduced grid impact, cost-effectiveness, and fault-tolerant capabilities, enabling efficient charging of multiple electric vehicles while minimizing stress on the power grid and reducing the need for bulky transformers.
Implementation Method 1
the grid-interface module converts the three-phase AC voltage with the medium amplitude to a DC voltage having a high amplitude
Implementation Method 2
the DC/DC converter module converts the DC voltage with the high amplitude to a DC voltage with a low amplitude
Implementation Method 3
a resonant network configured to produce a high-frequency AC current from a high-frequency AC voltage
Implementation Method 4
a primary coil electrically connected to the resonant network and configured to wirelessly transmit the high-frequency AC power corresponding to the high-frequency AC current to a pick-up coil
Data Source
AI summary
A system for transferring power wirelessly in a dynamic or stationary environment with a modular converter configuration. The system may include a grid interface operable to receive power from a power source, such as a three-phase grid power source, and provide power to the modular converter configuration.