Wireless power transfer apparatus, wireless power reception apparatus, and system including the same
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Solution Overview
Problem
Conventional wireless power transfer systems face challenges in maintaining a constant DC-link voltage and preventing overvoltage in small cooking appliances, where load states change frequently, making it difficult to optimize power output effectively.
Innovation Solution
A system where the wireless power reception apparatus determines a target power level and communicates it to the wireless power transfer apparatus, which adjusts the output power accordingly using an inverter with switching elements, ensuring constant voltage and preventing overvoltage by monitoring and controlling the output level based on received data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the wireless power transfer apparatus controls output power level based on input power variations (prior art method), then the power supply is simple to implement, but it cannot adapt to frequent load state changes in small cooking appliances and fails to maintain constant DC-link voltage
Solution Approach 1:
Instead of the transfer apparatus controlling power based on input variations, the reception apparatus now determines the target power level and communicates it to the transfer apparatus. This inversion allows the system to adapt to load state changes at the reception end while maintaining a relatively simple control structure by leveraging existing communication protocols.
Solution Approach 2:
The reception apparatus monitors its own DC-link voltage and load state, then feeds back the target power level information to the transfer apparatus. This feedback mechanism enables the system to maintain constant voltage despite frequent load changes, as the transfer apparatus adjusts output based on real-time reception apparatus status.
2Reliability
If the wireless power transfer apparatus uses conventional control based on input power variations, then the control logic is simple, but it cannot prevent overvoltage when load state changes rapidly
Solution Approach 1:
The reception apparatus determines the target power level in advance based on its current load state and DC-link voltage status before power transfer occurs. By communicating this target level to the transfer apparatus proactively, the system prevents overvoltage conditions from developing, as the transfer apparatus adjusts output to match the predetermined safe level.
Solution Approach 2:
The reception apparatus continuously monitors DC-link voltage and provides feedback about its status to the transfer apparatus. This real-time feedback enables the system to prevent overvoltage by adjusting power transfer before dangerous voltage levels are reached, rather than reacting after overvoltage occurs.
3Adaptability or versatility
If the wireless power transfer apparatus monitors current magnitude and limits output power (prior art), then the control method is straightforward, but it cannot optimize power delivery for different appliance specifications and rated values
Solution Approach 1:
The reception apparatus autonomously determines the appropriate target power level based on its own specifications and load state, eliminating the need for the transfer apparatus to store information about each appliance type. This universal approach allows any appliance to receive optimized power by having its own controller make the determination, rather than relying on the transfer apparatus to know its specific requirements.
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 approach allows for stable power transmission to various appliances, maintaining constant voltage and preventing overvoltage, thus protecting the appliances and improving power efficiency.
Implementation Method 1
an inductive coupling method is mainly used. This method uses the principle that a magnetic field is changed by an alternating current flowing through a primary coil among two adjacent coils when the alternating current with varying current intensity flows through the primary coil, whereby magnetic flux passing through a secondary coil is changed, and an induced electromotive force is generated on the secondary coil
Implementation Method 2
a magnetic field is changed by an alternating current flowing through a primary coil among two adjacent coils when the alternating current with varying current intensity flows through the primary coil, whereby magnetic flux passing through a secondary coil is changed, and an induced electromotive force is generated on the secondary coil
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A system includes a wireless power transfer apparatus and a wireless power reception apparatus. The wireless power transfer apparatus includes a transmitting coil, an inverter including switching elements, and a first controller configured to calculate an output level of power transmitted through the transmitting coil, receive data on a target level for power transmitted through the transmitting coil from the wireless power reception apparatus, and control the inverter based on comparing the output level and the target level. The wireless power reception apparatus includes a receiving coil, a rectifier configured to rectify power transmitted from the receiving coil, a capacitor connected to the rectifier, and a second controller configured to calculate a voltage applied to the capacitor, determine the target level based on comparing the calculated voltage and a first reference voltage, and transmit the target level to the wireless power transfer apparatus.