Soft-Switching Control Circuit for Wireless Power Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-frequency switching components in wireless electrical energy transmission systems experience significant switching losses and reliability issues due to difficulty in precise control of dead-time, leading to reduced safety and efficiency at extended transmission distances.
Innovation Solution
A soft-switching control circuit is implemented to control the switching device of the inverter circuit, allowing it to turn on at zero voltage, combined with a current regulation circuit to maintain constant frequency and amplitude, and a resonant capacitor to ensure efficient energy transmission, reducing switching losses and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the frequency of the alternating magnetic field is increased to extend transmission distance, then the transmission distance is improved, but the switching loss of the switching component increases significantly
Solution Approach 1:
The patent changes the waveform parameter of the switching device from conventional square wave to sine wave by introducing a sine wave generating circuit. This parameter change allows the switching device to turn on and off smoothly during zero-voltage periods, significantly reducing switching loss while maintaining high-frequency operation (6.78 MHz) for extended transmission distance
Solution Approach 2:
The patent introduces a sine wave generating circuit as an intermediary component between the switching device and the magnetic field generation system. This intermediary converts the switching signals into sine waveforms, enabling soft switching and reducing the harmful switching losses that would otherwise occur at high frequencies
2Length of moving object
If the operating frequency is increased to 6.78 MHz to achieve extended transmission distance, then the transmission distance is improved, but the control precision of dead-time between switching devices deteriorates
Solution Approach 1:
The sine wave generating circuit acts as an intermediary that naturally provides smooth transitions between switching states. The sine waveform inherently reduces the complexity of dead-time control at high frequencies by eliminating the abrupt transitions characteristic of square waves, making precise timing control more achievable at 6.78 MHz
Solution Approach 2:
The patent replaces the conventional mechanical/electronic switching control mechanism with a sine wave-based soft switching mechanism. This substitution eliminates the need for precise dead-time management by using the continuous, smooth nature of sine waves to naturally transition switching states without abrupt changes
3Device complexity
If conventional switching control is used at high frequency, then the circuit structure is simple, but the switching device may be wrongly connected or disconnected reducing safety and reliability
Solution Approach 1:
The sine wave generating circuit serves as a protective intermediary that ensures smooth and controlled switching transitions. By converting abrupt switching signals into gradual sine waveforms, it prevents the simultaneous wrong connection or disconnection of switching devices, thereby enhancing circuit safety and reliability while maintaining operational simplicity
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 solution significantly reduces switching losses, enhances transmission efficiency, and improves system reliability by allowing the switching device to turn on at zero voltage, maintaining constant energy transmission despite changes in coupling or load, and using fewer components to lower costs and stress on capacitors.
Implementation Method 1
The invertor receives DC voltage to generate AC voltage
Implementation Method 2
The primary transmitting coil is used for receiving the alternating voltage to generate an alternating magnetic field to transmit energy to the electrical energy receiving end
Implementation Method 3
the soft-switching control circuit controls the voltage between the two power ends of the switching device of the inverter circuit. During disconnection of the switching device, a voltage waveform between the two power ends of the switching device is a waveform in the form a fundamental wave superimposed with a third harmonic, such that when the switching device is turned on, the voltage between the two power ends of the switching device is lowered to zero
Implementation Method 4
The current regulation circuit receives the alternating voltage outputted from the inverter circuit to generate an alternating current signal with constant frequency and constant amplitude
Data Source
AI summary
A high-efficiency electrical energy transmitting end and a wireless electrical energy transmission device are provided. A soft-switching control circuit controls the voltage waveform between two ends of a switching device of an inverter circuit. During disconnection of the switching device, a voltage waveform between the drain electrode and the source electrode is a waveform in the form of a fundamental wave superimposed with a third harmonic, enabling the switching device to be turned on at zero voltage to decrease the switching loss. Through a current regulation circuit, the primary transmitting current is controlled to have constant frequency and constant amplitude to ensure that the primary transmitting energy won't be affected by the changes of the coupling and load and to enhance the transmission efficiency. The transmission efficiency of the wireless electrical energy transmission device of the present invention is high and the reliability is better.