Wireless Power Transmitter Control for Smooth Low-Step Power Regulation
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Solution Overview
Problem
Existing wireless charging systems face challenges in achieving linear and fine power regulation for devices with small rechargeable batteries, particularly when using low-cost USB wall-adapters with coarse voltage step sizes, which can cause power spikes and potential battery damage.
Innovation Solution
A method and system for wireless power transmitters that adjust transmitter power by combining discrete step changes in supply voltage with PID control loops to manage frequency or duty cycle, allowing the use of low-cost USB wall-adapters while ensuring smooth power regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If discrete step changes in supply voltage are used for power regulation, then device complexity is reduced and cost is lowered, but power regulation precision deteriorates due to coarse voltage step sizes
Solution Approach 1:
The power regulation process is segmented into two independent control loops: an outer voltage control loop that adjusts supply voltage in discrete steps, and an inner frequency/duty cycle control loop that provides fine-grained power adjustment. This segmentation allows each loop to operate independently with appropriate precision for its function, resolving the contradiction between simplicity and precision.
Solution Approach 2:
The invention transitions from single-dimension voltage control to two-dimensional control by adding frequency/duty cycle adjustment as a second control dimension. This enables the system to achieve fine power regulation precision not through voltage precision alone, but through the combined effect of voltage steps and frequency/duty cycle modulation.
2Productivity
If conventional power regulation methods are used, then power control is achieved, but power spikes occur that can damage small rechargeable batteries
Solution Approach 1:
The controller preliminarily adjusts the supply voltage to a target voltage level before activating the power conversion circuit, and continuously monitors the output voltage during the switching transient. This preliminary action and real-time monitoring prevent power spikes by ensuring the output voltage remains within safe boundaries during the critical transition period.
Solution Approach 2:
The system implements feedback control by continuously monitoring the output voltage and comparing it with the target voltage. The controller adjusts the supply voltage and power conversion circuit parameters based on the feedback signal, ensuring that power spikes are detected and corrected in real-time, thereby protecting the battery from damage.
3Stability of the object's composition
If bulky inductors are used in power conversion circuits, then power regulation stability is improved, but device volume and cost increase
Solution Approach 1:
The invention changes the operating parameters of the power conversion circuit, specifically operating at optimized frequency and duty cycle ranges that enable stable power regulation with reduced inductor size. By carefully selecting and dynamically adjusting these parameters, the system achieves stability without requiring bulky inductors.
Solution Approach 2:
The system employs dynamic control of the power conversion circuit, continuously adjusting frequency and duty cycle based on real-time power demands and system state. This dynamic operation allows the use of smaller inductors that can respond quickly to parameter changes, replacing the need for large, slow-response inductive components.
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
Enables smooth power regulation without requiring bulky inductors, reducing costs and heat generation, and effectively managing power spikes, thus protecting battery health.
Implementation Method 1
A wireless power transmitter is inductively coupled to a wireless power receiver
Data Source
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AI summary
A method for operating a wireless power transmitter includes: receiving a power control command from a wireless power receiver; computing a potential voltage change for a transmitter voltage of the wireless power transmitter in accordance with a target transmitter power and a present value of a transmitter current of the wireless power transmitter; comparing the potential voltage change with a discrete step size of a supply voltage; and in response to determining that the magnitude of the potential voltage change is equal to or larger than the discrete step size of the supply voltage, adjusting the transmitter power by: adjusting the supply voltage by one or more discrete steps; and controlling a power conversion circuit of the wireless power transmitter using a target current value computed in accordance with the target transmitter power and the adjusted supply voltage.