Variable Power Wireless Transmission via PWM Amplifier
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wireless power transmission systems face inefficiencies when varying power levels are required, as they often rely on complex and large switching-mode power supplies that decrease efficiency when output power changes, and adding variable power output functionality further complicates their configuration.
Innovation Solution
A high efficiency variable power transmitting apparatus that modulates a high frequency signal with constant amplitude by turning it ON and OFF, using a power amplifier to satisfy requested power levels, with a power supply converting AC voltage to DC voltage and providing a fixed voltage level to maintain maximum efficiency, eliminating the need for complex DC/DC converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching-mode power supply is used to provide variable power output, then the power level can be adjusted, but the efficiency decreases when output power changes and the configuration becomes complex
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (PWM) to switch the power supply voltage ON and OFF at high frequency. The duty cycle of these periodic pulses is varied to control the average power delivered to the amplifier, enabling variable power output while maintaining high efficiency through switching operation rather than linear regulation.
Solution Approach 2:
The patent changes the parameter of power supply voltage from a continuously variable analog signal to a digital pulse train with fixed amplitude but variable duty cycle. This parameter transformation allows the system to achieve variable average power through temporal modulation rather than voltage regulation, eliminating efficiency losses associated with power dissipation in regulation circuits.
2Adaptability or versatility
If a switching-mode power supply is used to provide variable power output, then the power level can be adjusted, but the device complexity increases
Solution Approach 1:
The patent extracts the variable power control function from the power supply circuit itself and relocates it to the signal processing domain. By using a fixed-voltage switching power supply combined with PWM modulation of the amplifier input signal, the system achieves variable power output without requiring a complex variable-voltage power supply, thereby simplifying the power supply configuration.
Solution Approach 2:
The patent introduces PWM duty cycle modulation as an intermediary mechanism between the fixed power supply and the amplifier. This intermediary allows the system to achieve variable power output by controlling the temporal distribution of fixed-voltage pulses rather than varying the voltage level directly, simplifying the power supply architecture while maintaining adaptability.
3Power
If the power supply voltage is varied to control output power, then the power level can be adjusted, but the amplifier efficiency decreases from its maximum
Solution Approach 1:
The patent uses periodic switching of the power supply voltage at the amplifier rather than continuous analog voltage control. By switching the voltage ON and OFF at the amplifier input with variable duty cycle, the system maintains the amplifier in its most efficient operating region (fixed voltage) while achieving variable average power output through temporal modulation.
Solution Approach 2:
The patent applies dynamics by transitioning from static voltage control to dynamic temporal modulation. The power supply voltage switches dynamically between ON and OFF states with duty cycle adjusted in real-time based on required output power, allowing the amplifier to operate at peak efficiency points while adapting output power levels through dynamic control of pulse width rather than voltage magnitude.
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 efficient wireless power transmission with variable power levels while maintaining high efficiency and simplifying the power supply configuration, reducing the complexity and size of the system.
Implementation Method 1
a power amplifier (PA) configured to amplify the variable power to satisfy a requested power level of a target device
Implementation Method 2
a transmitting unit configured to transmit the amplified variable power to the target device through a transmission coil or an antenna
Implementation Method 3
One conventional wireless power transmission technology uses a resonance characteristic of a radio frequency (RF) device
Data Source
AI summary
A high efficiency variable power transmitting apparatus outputs a variable power by modulating, with respect to a time axis, a high frequency signal having a constant amplitude by turning the high frequency signal ON and OFF, amplifying the variable power to satisfy a requested power level of a target device based on a supply voltage having a predetermined level, converting an alternating current (AC) voltage received from a power source to a direct current (DC) voltage, generating the supply voltage having the predetermined level based on the DC voltage, and providing the supply voltage having the predetermined level to the PA.