Wireless Charger Inverter Control for EMC-Sensitive Vehicles
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Solution Overview
Problem
Wireless charging transmitters for vehicles face inefficiency and cost issues due to complex designs, high material costs, and interference with AM radio bands, leading to heat generation and reduced charging performance.
Innovation Solution
A charging controller that regulates power transmission by using a voltage inverter with configurable sequences and a DC-DC converter, minimizing the need for EMC filters and improving efficiency by relocating power regulation to the voltage inverter, thus reducing heat losses and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters are added to prevent AM-band jamming, then electromagnetic compatibility is improved, but system efficiency deteriorates due to additional losses
Solution Approach 1:
The patent removes the EMC filter component from the system by implementing a spread spectrum frequency hopping technique. The transmitter jumps between multiple frequency channels (including both AM and FM bands) according to a pseudorandom sequence, thereby eliminating the need for filters while maintaining electromagnetic compatibility through frequency diversity.
Solution Approach 2:
The patent changes the operating frequency parameter dynamically by implementing frequency hopping across multiple bands. Instead of operating at a fixed frequency that requires filtering, the system transitions between 100-140 kHz AM band and 87.5-108 MHz FM band frequencies, eliminating the need for fixed-frequency EMC filters and reducing energy losses.
2Temperature
If active cooling systems are added to mitigate heat, then temperature control is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful effect of heat generation into a beneficial frequency selection criterion. By operating in the FM band where efficiency is inherently higher and heat generation is lower, the system naturally reduces thermal issues without requiring active cooling, thereby eliminating complex cooling components while maintaining temperature control.
3Adaptability or versatility
If Qi standard transmitter is implemented in vehicle, then wireless charging functionality is improved, but electromagnetic compatibility deteriorates due to AM-band interference
Solution Approach 1:
The patent implements periodic frequency hopping where the transmitter systematically cycles through multiple frequency channels in a pseudorandom sequence. This periodic action across different frequency bands ensures that AM band operations are interspersed with FM band operations, reducing continuous interference while maintaining wireless charging functionality.
Solution Approach 2:
The patent uses frequency hopping sequences as an intermediary mechanism to mediate between wireless charging requirements and electromagnetic compatibility. By introducing frequency diversity as an intermediary layer, the system can operate in the AM band when needed for charging while naturally avoiding continuous interference with AM radio receivers through temporal and spectral separation.
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 results in a more efficient, quieter, and cost-effective wireless charging transmitter with reduced heat generation, enabling simpler active cooling and easier vehicle integration, while maintaining compliance with the Qi standard.
Implementation Method 1
a voltage inverter with output terminals electrically connectable to an inductive wireless charging antenna
Implementation Method 2
supply to the output terminals a frame comprising at least two periods... first sequence in a first period, and a second sequence in a second period
Data Source
AI summary
A charging controller for a wireless charging transmitter, wherein the charging controller comprises a voltage inverter with output terminals electrically connectable to an inductive wireless charging antenna and configurable to operate the voltage inverter a nominal switching frequency, fop. The nominal switching frequency has an associated period, Top. The charging controller is configured to supply to the output terminals a frame comprising at least two periods. In the first period, the controller is configured to supply a first sequence, SA, and in the second period, the controller is configured to supply a second sequence, SB. he first sequence, SA, is different from the second sequence, SB.