Sinusoidal Signal Generator for Vehicle Wireless Charger
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Solution Overview
Problem
Existing inductive charging systems for mobile devices in vehicles face challenges with electromagnetic compatibility and noise emissions, particularly near sensitive vehicle modules, due to the use of square-wave signals which lead to high electromagnetic radiation and incompatibility issues.
Innovation Solution
A wireless power transfer system using a charger with a sinusoidal signal generator and a push-pull output stage, which includes a power source, transmitter coil, and a level-adjustment device for closed-loop control of the sinusoidal signal, optimizing electromagnetic compatibility and reducing noise emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a square-wave signal is used to actuate the output stage, then the charging function is achieved, but electromagnetic radiation and noise emissions increase significantly
Solution Approach 1:
The patent changes the signal waveform parameter from square-wave to sinusoidal. The sinusoidal signal generator produces a sinusoidal control signal that actuates the output stage, fundamentally altering the electrical characteristics of the power transfer process. This parameter change eliminates the abrupt transitions inherent in square-wave signals, thereby reducing electromagnetic radiation and noise emissions while maintaining effective charging functionality.
2Object-affected harmful factors
If a sinusoidal signal is used to actuate the output stage, then electromagnetic compatibility is improved, but additional signal generation components are required
Solution Approach 1:
The patent employs a cost-effective sinusoidal signal generator implementation that does not require expensive precision components. The signal generator can be realized using standard operational amplifiers and passive components, making it an affordable addition to the charging system. This approach accepts minor signal imperfections that do not affect charging performance, thereby avoiding the need for costly high-precision oscillators or frequency synthesisers.
3Object-affected harmful factors
If expensive shielding measures are implemented, then electromagnetic compatibility near sensitive modules is improved, but system cost and complexity increase
Solution Approach 1:
The patent converts the potentially harmful square-wave signal into a beneficial sinusoidal signal at the source, rather than attempting to shield against the harm after it is generated. By generating a sinusoidal control signal from the outset, the system inherently produces lower electromagnetic interference, eliminating the need for additional shielding measures around sensitive vehicle modules. This proactive approach is more cost-effective than reactive shielding.
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 system achieves enhanced electromagnetic compatibility, reduced noise emissions, and cost-effective design by using a sinusoidal signal to actuate the output stage, allowing for efficient charging of mobile devices while adhering to automotive industry norms.
Implementation Method 1
The alternating inductance between two magnetic coils is utilized here to transfer electrical output through magnetic induction. The transmitter coil is configured to inductively transfer electric power to the mobile device.
Implementation Method 2
In a resonant system, the source and receiving coils are coupled to capacitors to form electrical oscillating circuits, so that a portion of the reactive impedance of the coils is canceled.
Data Source
AI summary
The present disclosure introduces a charger for inductively charging a mobile device inside a motor vehicle. The charger includes a power source configured to supply electrical energy in the form of DC voltage, a transmitter coil for inductively transferring power to the mobile device, a signal generator configured to generate a sinusoidal signal, and an output stage that is coupled to the power source, the transmitter coil and the signal generator. The output stage is configured to receive the sinusoidal signal as a control signal and to supply to the transmitter coil a current flow, corresponding to the control signal, of the energy provided by the power source.