Inductive Wireless Power Control with Duty-Cycle Settling
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Solution Overview
Problem
Existing wireless power transfer systems using inductive coupling face challenges in achieving reliable and flexible operation, particularly in adjusting power delivery to match target power levels without overshooting and minimizing demands on knowledge of the transmission link's behavior.
Innovation Solution
A method involving a device with a rectifier, inverter, and control unit that adjusts the frequency and duty cycle of a pulse width modulated control signal to regulate power delivery, starting with a safe undershoot and incrementally increasing the target power while measuring actual power, using specific mathematical calculations to set duty cycles and frequencies, ensuring quick adjustment and minimizing overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the power delivery is adjusted rapidly to match target power levels, then the response speed is improved, but the risk of overshooting increases
Solution Approach 1:
The method performs preliminary actions by first determining an initial duty cycle that intentionally undershoots the target power level, then iteratively adjusting the duty cycle in controlled increments. This preliminary undershooting prevents immediate overshoot and allows the system to approach the target power level safely and accurately.
Solution Approach 2:
The system dynamically adjusts the duty cycle based on measured actual power levels, continuously adapting the control parameters. The adjustment strategy changes during operation - starting with conservative increments and potentially accelerating as it approaches the target, optimizing both response speed and accuracy.
2Ease of operation
If the system operation is made more flexible with adaptive control, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The method implements feedback control by continuously measuring the actual power delivered and using this information to adjust the duty cycle in subsequent iterations. This feedback mechanism enables flexible adaptive control while keeping the algorithm relatively simple - it only requires comparing measured power to target power and adjusting accordingly.
Solution Approach 2:
The system performs self-service by automatically determining appropriate duty cycles and adjustment increments without requiring external intervention or complex pre-programming. The control algorithm adapts to the specific transmission conditions and load characteristics autonomously, simplifying operation while maintaining reasonable complexity through self-adjustment.
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 method allows for rapid and precise adjustment of power delivery to target levels, limiting overshoot and reducing the need for detailed knowledge of the transmission link's behavior, ensuring reliable and flexible operation.
Implementation Method 1
device for wirelessly transmitting energy towards an electrical consumer by means of inductive coupling
Data Source
Figure 1~2
AI summary
A method for operating a device for wirelessly transmitting energy towards an electrical load by means of inductive coupling, wherein the device comprises: - a rectifier for generating a DC voltage from a mains voltage, - an inverter supplied by the DC voltage, which is configured to generate a pulse-width modulated control signal, and - a coil controlled by the pulse-width modulated control signal, by means of which an alternating magnetic field can be generated for transmitting the energy, wherein the method comprises the steps of: - controlling an actual electrical power output by the inverter to a predefinable target electrical power, wherein a frequency and a duty cycle of the pulse-width modulated control signal serve as control variables, - characterized in that the following steps are carried out to control to the target power: a) setting a start frequency (f_0),b) Setting a start duty cycle (DC_1) such that the target power is undershot, c) Measuring the actual electrical power output by the inverter at the set start frequency (f_0) and the set start duty cycle (DC_1), d) Selecting a settling-in target power that is less than or equal to the target power, e) Calculating a duty cycle (DC_2) that corresponds mathematically to the settling-in target power, f) Setting the calculated duty cycle (DC_2), g) Measuring the actual electrical power output by the inverter at the set frequency (f_0) and the set duty cycle (DC_2), and h) Repeating steps d) to g) with increasing settling-in target power until the deviation between the target power and the actual power falls below a predetermined threshold.