Settable Compensating Circuit for Wireless EV Charging
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Solution Overview
Problem
Inductive energy transfer systems face inefficiencies due to changes in operating frequency caused by varying distances and offsets between charging stations and electric vehicles, limiting power transfer and efficiency within a narrow air gap and offset range.
Innovation Solution
A settable compensating circuit connected to the electronic coil allows for finely-tuned frequency adjustment, minimizing frequency changes and enabling reliable high-power, high-efficiency charging operations even under unfavorable conditions by adjusting capacitors in series and parallel configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wireless energy transfer by alternating magnetic field is used, then mechanical connection complexity is reduced, but operating frequency changes substantially with distance and offset variations
Solution Approach 1:
The patent implements a settable compensating circuit with adjustable capacitors that dynamically adapt to changing coupling conditions. The circuit transitions from static to dynamic operation, allowing real-time adjustment of resonant frequency to maintain optimal operating conditions despite variations in distance and offset between charging station and vehicle.
Solution Approach 2:
The patent changes the electrical parameters (capacitance values) of the compensating circuit to compensate for frequency drift. By adjusting the capacitors in the compensating circuit, the system modifies its electrical characteristics to counteract the effects of varying air gap and offset, thereby stabilizing the operating frequency.
2Power
If coil circuit parameters change beyond comparison value, then power transfer capability is reduced, but efficiency level decreases
Solution Approach 1:
The patent employs a control unit that monitors the coupling factor and adjusts the compensating circuit parameters accordingly. This feedback mechanism ensures that the system maintains optimal operating conditions by detecting deviations in coupling and automatically compensating through capacitor adjustment, thereby preserving both power transfer capability and efficiency.
3Ease of operation
If inductive energy transfer is used, then charging convenience is improved, but reliable operation is limited to narrow air gap and offset range
Solution Approach 1:
The system transitions from static to dynamic operation by implementing adjustable capacitors in the compensating circuit. This allows the system to adapt to a wider range of air gaps and offsets, expanding the reliable operational range while maintaining charging convenience. The dynamic adjustment capability enables the system to compensate for positioning variations that would otherwise limit reliable operation.
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 reliable and efficient energy transfer to electric vehicles, adapting to large distances and offset tolerances, and optimizing power and efficiency levels, allowing for consistent charging performance across varying positions and conditions.
Implementation Method 1
the charging device receives energy made available by an alternating magnetic field by means of an electronic coil which interacts with the alternating magnetic field
Implementation Method 2
A settable compensating circuit connected to the electronic coil allows for finely-tuned frequency adjustment, minimizing frequency changes
Data Source
AI summary
An electrically powered vehicle has a drive apparatus which includes an electric machine and an electrical energy storage device connected to the electric machine. A charging device is connected to the electrical energy storage device for the wireless transfer of energy by way of an alternating magnetic field. For that purpose, the charging device has an electronic coil which interacts with the alternating magnetic field. The electronic coil is connected to an adjustable compensating circuit.