Wireless Charging Circuit PWM Power Control
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Solution Overview
Problem
Existing wireless charging systems face inefficiencies and increased circuit costs due to the need for additional circuits to adjust output power, which limits power density and system efficiency.
Innovation Solution
A wireless charging system that includes a DC/AC converter with a control component generating drive signals to intermittently switch between working and non-working states, allowing the system to adjust output power without additional circuits, using a bridge-structure circuit with switching transistors for soft switching and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an impedance matching circuit with adjustable capacitor and inductor is added to adjust output power, then the output power can be adjusted to match different battery capacities, but the circuit cost and volume increase
Solution Approach 1:
The patent extracts the power adjustment function from the traditional impedance matching circuit approach. Instead of adding adjustable capacitors and inductors, the invention removes these components and achieves power adjustment through pulse width modulation (PWM) control of the full-bridge converter, thereby reducing circuit complexity and volume while maintaining adaptability.
Solution Approach 2:
The patent replaces mechanical adjustment methods (such as mechanical switches or relays for adjusting capacitance and inductance) with electronic PWM control. The control circuit generates PWM signals to regulate the duty cycle of switching transistors, enabling continuous power adjustment without mechanical moving parts, thus reducing volume and improving reliability.
2Adaptability or versatility
If additional circuits are added to adjust output power, then power adjustment is achieved, but system efficiency and power density are reduced
Solution Approach 1:
The patent employs periodic pulse width modulation (PWM) control to adjust output power. The full-bridge converter switches periodically with variable duty cycle, allowing efficient power transfer by controlling the on-time of switching transistors. This periodic switching approach minimizes energy losses compared to continuous operation with additional regulation circuits.
Solution Approach 2:
The patent implements dynamic power adjustment through real-time PWM control of the full-bridge converter. The duty cycle of switching transistors is dynamically varied based on load requirements and battery charging status, enabling efficient power adaptation without fixed additional circuits that would continuously consume energy.
3Adaptability or versatility
If a relay is used as the controllable switch to adjust capacitance, then the capacitance can be adjusted, but the impact resistance is limited
Solution Approach 1:
The patent replaces mechanical relays with solid-state switching transistors (such as MOSFETs or IGBTs) in the full-bridge converter. These electronic switches have no mechanical moving parts, providing superior impact resistance and reliability. The switches are controlled by PWM signals to achieve capacitance and power adjustment without mechanical components that could fail under impact.
4Adaptability or versatility
If a mechanical structure is used to adjust inductance, then the inductance can be adjusted, but the circuit costs and volume increase
Solution Approach 1:
The patent replaces mechanical inductance adjustment structures with electronic PWM control of the full-bridge converter. Instead of using mechanical switches or relays to adjust inductance, the invention uses controlled switching of transistors to dynamically adjust the effective inductance seen by the resonant circuit. This eliminates mechanical components, reducing volume and cost while improving reliability.
Solution Approach 2:
The patent changes the operating parameters (duty cycle and frequency) of the full-bridge converter to achieve power and impedance adjustment. By varying the duty cycle of PWM signals, the effective inductance and power transfer are adjusted without physically changing inductor components. This parameter-based control eliminates the need for mechanical adjustment structures.
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 enhances the system's efficiency and power density by ensuring the average power of the actual load matches the required load, reducing switching losses and circuit complexity.
Implementation Method 1
the wireless transmitter is configured to convert, into the high-frequency magnetic field, the high-frequency alternating current voltage that is obtained through conversion when the DC/AC converter is in the working state, and transmit the high-frequency magnetic field
Implementation Method 2
the receive end senses the electromagnetic signal and generates a current to charge a battery
Data Source
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AI summary
The present invention discloses a wireless charging circuit, a wireless charging system, and a circuit control method, and belongs to the field of wireless charging technologies. The wireless charging circuit includes: a DC/AC converter, a wireless transmitter, a control component, and a wireless communications component. The wireless communications component is configured to receive charging parameters fed back by a receive end; the control component is configured to send a first drive signal or a second drive signal to the DC/AC conversion module based on the charging parameters; and the DC/AC converter is configured to be in a working state under control of the first drive signal, and convert a direct current voltage in the working state; or be in a working-stopped state under control of the second drive signal, and skip converting a direct current voltage in the working-stopped state. This resolves a problem that circuit costs and a volume are increased in an existing output power adjustment method, and achieves effects of making an average power of actual load of the receive end equal to or close to a required power of the load, and improving efficiency and power density of the wireless charging system.