LCC Wireless EV Charging Power Control Without Secondary Feedback
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Solution Overview
Problem
Conventional wireless power transfer systems for electric vehicles fail to provide fast charging and effective operation across low and high load conditions due to the limitations of LCC compensation circuits, which are designed for high power levels but struggle with varying load and coupling factors.
Innovation Solution
A wireless power transfer system with primary-side control using an LCC-series network and sensing circuitry to measure signals independent of the coupling factor and load, employing a controller to produce a feedback signal for driving the primary-side inverter, allowing for precise power regulation without secondary-side feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LCC compensation circuit is used to compensate for large inductive reactance of coupling coils, then coil size can be reduced to accommodate high power levels, but the system fails to provide fast charging and effective operation across low and high load operating conditions
Solution Approach 1:
The patent applies dynamics by making the compensation network adjustable and adaptive to varying operating conditions. The LCC compensation circuit parameters (inductance and capacitance values) are dynamically tuned based on real-time measurements of coupling factor and load conditions, allowing the system to maintain optimal performance across wide ranges of power levels from low to high load operations.
Solution Approach 2:
The patent implements parameter changes by varying the compensation network parameters (inductance L and capacitance C values) to match different operating conditions. By changing these parameters dynamically, the system can compensate for variations in coupling factor between primary and secondary coils, enabling effective operation across both low and high load conditions while maintaining fast charging capability.
2Reliability
If conventional LCC compensation circuit operates at rated power levels, then it can maintain stable operation, but it fails to provide fast charging and effective operation at low and high load conditions
Solution Approach 1:
The patent employs feedback mechanisms where the system continuously monitors operating conditions (coupling factor, load variations) and adjusts the compensation network parameters accordingly. This closed-loop control ensures stable operation at rated power levels while enabling fast charging at varying load conditions, as the feedback allows real-time optimization of the LCC compensation circuit to maintain reliability across all operating points.
3Power
If LCC compensation circuit is designed for high power levels, then it can accommodate high power transmission, but it struggles with varying load and coupling factors
Solution Approach 1:
The patent makes the LCC compensation circuit dynamic by enabling real-time adjustment of its parameters. The system can adapt its inductance and capacitance values in response to varying load conditions and coupling factors between primary and secondary coils, allowing it to maintain high power transmission capability while being versatile across different operating scenarios.
Solution Approach 2:
The patent utilizes parameter changes by varying the compensation network's inductance and capacitance values to match different operating conditions. This allows the system to maintain optimal performance for high power transmission while adapting to varying load and coupling factors, effectively resolving the contradiction between power level and adaptability.
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
Enables efficient and fast charging of electric vehicles by accurately controlling output power independent of load and coupling variations, enhancing system performance and reliability.
Implementation Method 1
a primary coil configured to wirelessly transmit the high-frequency AC voltage, where the transmitted high-frequency AC voltage is received by a pick-up coil of an onboard module of the WPT system when the pick-up coil is disposed adjacent to the primary coil
Implementation Method 2
The off-board module may include a primary-side compensating network configured to couple the high-frequency AC voltage between the primary-side inverter and the primary coil
Data Source
AI summary
A system and method for controlling output power in an LCC-series wireless power system based on one or more primary-side variables, such as a peak voltage in an LCC-series compensation circuit that is provided in conjunction with a primary coil for transmitting power wirelessly to an electric vehicle. The coupling factor between the primary coil and a receiver may be in the range of 0.1-0.5, and a target power level may be in a range of 50-150 kW.