Inductive Power Transmitter Primary Side Control
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Solution Overview
Problem
Existing inductive power transfer (IPT) systems face challenges in regulating power to the load without requiring complex and costly measurement and communication of receiver-side operational parameters, especially at light loads where resonant waveforms become non-sinusoidal, leading to inefficiencies and instability.
Innovation Solution
An IPT power transmitter with a resonant circuit, a controllable power supply, a switching circuit, and current sensors that adjust the duty cycle or output voltage based on the current ratio to control the power supplied to the resonant circuit, eliminating the need for complex control circuitry and accurate phase measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transmitter-side power control is used to regulate power, then power regulation capability is improved, but system complexity increases due to required measurement and communication of receiver-side parameters
Solution Approach 1:
The transmitter controller autonomously regulates power by monitoring its own output current and adjusting the duty cycle accordingly, eliminating the need for receiver-side parameter communication. The system serves itself by using internal measurements (output current and resonant circuit current) to automatically control power delivery without external feedback.
Solution Approach 2:
The invention extracts and eliminates the complex communication and measurement infrastructure between transmitter and receiver. By removing the requirement for receiver-side operational parameter communication and replacing it with simple duty cycle control based on output current ratio, the system achieves power regulation without the burden of complex control circuitry.
2Device complexity
If primary side only control is employed, then device complexity is reduced, but system stability deteriorates under sudden load changes
Solution Approach 1:
The controller implements feedback by continuously monitoring the output current and using the current ratio to dynamically adjust the duty cycle. This closed-loop control mechanism enables the system to respond to load changes and maintain stability without requiring complex receiver-side control circuitry.
3Measurement precision
If accurate phase measurements are implemented, then power control precision is improved, but cost and complexity increase due to expensive measurement equipment
Solution Approach 1:
The invention replaces expensive phase measurement equipment with simple current sensing circuits that measure output current and resonant circuit current. By using affordable current sensors and calculating the current ratio, the system achieves effective power control without investing in costly phase measurement instrumentation.
Solution Approach 2:
The invention substitutes complex electrical measurement systems (phase measurement equipment) with simpler current sensing and ratio calculation. By replacing the need for accurate phase detection with current ratio monitoring, the system achieves power control precision through a simpler, more cost-effective electrical measurement approach.
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 solution provides efficient and cost-effective power regulation across a wide range of load conditions and coil spacings, reducing complexity and cost while maintaining stability, even with sudden changes in load requirements.
Implementation Method 1
a primary side (i.e., an inductive power transmitter) will include a transmitting coil or coils configured to generate an alternating magnetic field. This magnetic field induces an alternating current in the receiving coil or coils of a secondary side
Implementation Method 2
In some instances, the transmitting coil(s) or the receiving coil(s) may be suitably connected with capacitors to create a resonant circuit. This can increase power throughput and efficiency at the corresponding resonant frequency.
Data Source
AI summary
An inductive power transmitter for an inductive power transfer system including a power regulation circuit utilising only primary side parameters to control power flow. The duty cycle of the waveform applied to the transmitter coil is adjusted based on the ratio of the output current of the power supply and the current supplied to the resonant circuit (the current ratio). This may be further compensated based on the amount of power supplied to the transmitter.