Wireless Power Transmitter PWM Control for Soft Switching
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Solution Overview
Problem
Conventional wireless power transfer systems face inefficiencies and potential component failure due to shifting from a soft switching state to a hard switching state when loading conditions exceed limits or foreign objects are present, leading to increased energy loss and component temperature rise.
Innovation Solution
A transmitter-based control system that processes real-time current and voltage signals from the inverter to adjust pulse width modulation (PWM) parameters, such as frequency, duty cycle, and phase, to maintain the system in a soft switching state without using feedback from the receiver side, ensuring high efficiency across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If compensation networks are used to maintain high efficiency, then the inverter can operate in soft switching state within limited loading conditions, but when loading conditions exceed the limited range or foreign objects are present, the system shifts to hard switching state causing increased energy loss and component temperature rise
Solution Approach 1:
The patent implements dynamic control of PWM parameters (frequency, duty cycle, phase) based on real-time monitoring of inverter current and voltage waveforms. This allows the system to adapt to varying loading conditions and maintain soft switching state dynamically, rather than being limited to fixed loading ranges. The controller continuously adjusts parameters to prevent transition to hard switching state even when loading conditions change or foreign objects are present.
Solution Approach 2:
The patent employs feedback control by monitoring the inverter's current and voltage waveforms and using this information to adjust PWM parameters. The controller detects the actual switching state and loading conditions, then modifies control parameters accordingly to maintain optimal operation. This closed-loop feedback mechanism enables the system to respond to foreign objects and loading changes while maintaining high efficiency.
2Reliability
If receiver-side feedback is used to control the WPT system, then the system can adapt to loading conditions, but the implementation becomes more complex and efficiency is reduced
Solution Approach 1:
The patent extracts the control function from the receiver side and relocates it to the transmitter side. By monitoring inverter waveforms and controlling PWM parameters at the transmitter, the system eliminates the need for complex receiver-side feedback circuits and communication protocols. This extraction simplifies the overall system architecture while maintaining reliable control of the wireless power transfer process.
Solution Approach 2:
The transmitter controller performs self-control by monitoring its own inverter waveforms and autonomously adjusting PWM parameters without requiring feedback from the receiver. The system serves itself by using internal sensor data to maintain optimal operation, eliminating the need for external feedback loops and reducing overall system complexity while preserving stability.
Data Source
AI summary
A transmitter of a wireless power transfer system is provided. The transmitter comprises a processor and a memory. The memory stores executable instructions that, in response to execution by the processor, can cause the processor to receive one or more signals generated by an inverter of the transmitter. The processor can measure or obtain a first value of the one or more signals and perform a comparison between the first value and a second value of the one or more signals. Based on the comparison, the processor can adjust at least one parameter of a pulse width modulation (PWM) signal generated by the processor that controls the inverter to maintain the inverter in a soft switching state.