Inductive Power Transfer Controller Hard Switching Protection
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Solution Overview
Problem
Inductive power transfer systems face efficiency drops and potential thermal overload due to hard-switching modes when antenna sizes are reduced and separation offset ranges increase, leading to undesirable capacitive reactance and increased power dissipation.
Innovation Solution
A controller is used to monitor and manage the switching of power converter switches, disabling them from switching at scheduled times if a zero-current crossover point occurs before the scheduled time to prevent hard switching, ensuring soft-switching modes are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If antenna size is reduced and separation offset range is increased, then device compactness and flexibility are improved, but hard-switching occurs causing efficiency to drop and thermal overload to increase
Solution Approach 1:
The controller performs preliminary detection of the zero-current crossover point timing relative to the scheduled switch switching time. When the crossover point is detected to occur before the scheduled switching time, the controller preemptively disables the switch to prevent hard-switching from occurring, thereby avoiding energy loss and thermal overload before they can happen.
Solution Approach 2:
The system continuously monitors the current waveform to detect the zero-current crossover point and compares its timing with the scheduled switch switching time. This feedback mechanism allows the controller to adjust switch operation in real-time, disabling switches when detection indicates hard-switching conditions are present, thus maintaining efficiency despite reduced antenna size and increased offset ranges.
2Volume of moving object
If antenna size is reduced and separation offset range is increased, then device compactness and flexibility are improved, but system efficiency drops due to hard-switching
Solution Approach 1:
The controller detects the zero-current crossover point timing in advance and preemptively disables switches when the crossover point occurs before the scheduled switching time. This preliminary protective action prevents hard-switching events that would otherwise cause efficiency drops, enabling the system to maintain high power transfer efficiency even with compact antennas and larger separation offsets.
Solution Approach 2:
The system continuously monitors current waveforms and compares zero-current crossover timing with scheduled switch operations. This real-time feedback enables dynamic adjustment of switch operation to prevent hard-switching, thereby maintaining optimal inductive power transfer efficiency despite physical constraints on antenna size and separation distance.
3Loss of substance
If antenna size is reduced and separation offset range is increased, then material usage is reduced, but thermal overload risk increases due to hard-switching
Solution Approach 1:
The controller performs preliminary detection of hard-switching conditions by comparing zero-current crossover timing with scheduled switch operations. When hard-switching is detected, the controller preemptively disables the switch to prevent the high current stress and power dissipation that would lead to thermal overload, enabling safe operation with reduced material usage.
Solution Approach 2:
The system continuously monitors current waveforms and provides feedback to the controller about zero-current crossover timing. This feedback mechanism enables real-time detection and prevention of hard-switching conditions, thereby preventing excessive power dissipation and thermal overload while allowing the system to operate with compact antennas and reduced material usage.
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 prevents thermal overload and maintains efficiency by preventing hard-switching, allowing for smaller antenna sizes and increased offset ranges while ensuring safe operation and reduced material usage.
Implementation Method 1
Inductive power transfer uses an oscillating current passing through a primary coil (i.e., a transmit antenna) of a source to generate an oscillating magnetic near-field that induces currents in a secondary coil (i.e., a receive antenna) of a load
Implementation Method 2
resonant network tuning and operation to run near or even exceed soft-switching mode boundaries
Data Source
AI summary
An inductive power transfer system includes a power converter and a controller. The power converter includes switches. The controller to switch the switches according to a schedule to cause the power converter to output a voltage and a current to a resonant network. The controller to compare a zero-current crossover point of the current and the schedule to determine whether the zero-current crossover point occurs prior to a scheduled time that one or more of the switches are be switched. The controller to disable the switches from switching when the zero-current crossover point occurs prior to the scheduled time such that the switches do not switch at the scheduled time thereby preventing hard switching of the switches from occurring.