Wireless Power MOSFET Control With Dynamic Dead-Time Tuning
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Solution Overview
Problem
Conventional wireless power transmitters face challenges in efficiently controlling both internal and external MOSFETs due to differing turn-on/turn-off characteristics, leading to sub-optimal performance under various operating conditions, especially when using both internal and external MOSFETs in half-bridge configurations.
Innovation Solution
Implementing a controller and analog front end (AFE) to generate pulse width modulation (PWM) signals for controlling both internal and external MOSFETs, utilizing programmable delays, fixed ON times, and dithering to optimize dead time and avoid interference, ensuring synchronized switching of MOSFETs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control methods are used for both internal and external MOSFETs, then the system structure remains simple, but the performance is sub-optimal due to differing turn-on/turn-off characteristics
Solution Approach 1:
The patent implements dynamic dead-time optimization by adjusting the dead-time parameter based on operating conditions. The controller dynamically modifies the dead-time value to accommodate different turn-on/turn-off characteristics of internal and external MOSFETs under varying operating conditions, thereby optimizing performance without requiring a completely separate control mechanism for each MOSFET type.
2Loss of energy
If fixed dead-time is used for MOSFET control, then the control mechanism is simple, but power loss and hard switching occur under varying operating conditions
Solution Approach 1:
The patent changes the dead-time parameter dynamically based on operating conditions to minimize power loss and avoid hard switching. By adjusting the dead-time value according to the specific operating state (temperature, load, frequency), the system optimizes energy efficiency without requiring fundamentally different control mechanisms, thus balancing parameter adaptability with control simplicity.
3Stability of the object's composition
If internal and external MOSFETs are controlled independently without coordination, then the control mechanism is simple, but frequency stability deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the controller monitors the switching states and performance of both internal and external MOSFETs. Based on this feedback, the controller adjusts the dead-time and switching coordination to maintain frequency stability. This feedback-based coordination ensures that the differing characteristics of internal and external MOSFETs do not degrade system frequency stability while avoiding overly complex independent control mechanisms.
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
Achieves optimized performance by minimizing power loss and hard switching, enhancing system efficiency and frequency stability in wireless power transmission systems.
Implementation Method 1
When a transmission coil of the transmitter and the receiver coil of the receiver are positioned close to one another they form a transformer that facilitates inductive transmission of an alternating current (AC) power between the transmitter and the receiver
Implementation Method 2
The receiver often includes a rectifier circuit that converts the AC power into a direct current (DC) power that may be utilized for various loads or components that require DC power to operate
Data Source
AI summary
Systems and methods for wireless power transmission are described. A wireless power transmitter can include a coil, an analog front end (AFE) and a controller. The AFE can include a set of internal metal-oxide-semiconductor field-effect transistors (MOSFETs). The controller can be configured to generate a set of pulse width modulation (PWM) signals. The controller can be further configured to send the set of PWM signals to the AFE. At least one of the AFE and the controller can be configured to perform dead time optimization by using the PWM signals to control at least one of the set of internal MOSFETs and a set of external MOSFETs connected between the AFE and the coil. The coil can be driven by the set of internal MOSFETs and the set of external MOSFETs.