Inductive Coupler Resonance Frequency Compensation
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Solution Overview
Problem
Inductive rotary transmitters in computer tomographs face challenges in maintaining a constant output voltage due to mechanical and electrical tolerances, requiring additional components like rotary transmitters for feedback or additional converter stages on the rotating side, which increase costs and complexity.
Innovation Solution
A method involving a series resonant circuit with a power generator and control device to measure and adjust resonance frequencies, allowing for primary-side control to maintain a constant output voltage without the need for rotary transmitter feedback or additional converters, using a series resonant circuit with a power generator and control device to measure and adjust resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a series resonant circuit is used to transmit electrical energy via the inductive rotary transmitter, then large amounts of power can be transmitted at resonant frequency, but the leakage inductance causes frequency-dependent impedance that significantly influences transmission properties and makes output voltage unstable due to mechanical and electrical tolerances
Solution Approach 1:
The patent measures the resonance frequency of the series resonant circuit before normal operation and uses this measurement to determine a compensation value. This preliminary action allows the system to pre-calculate the necessary frequency deviation from nominal resonance to compensate for tolerances, ensuring stable output voltage before power transmission begins.
Solution Approach 2:
The patent changes the operating frequency parameter by deviating from the nominal resonant frequency. By calculating a compensated frequency based on measured resonance frequency and tolerance values, the system adjusts the frequency parameter to maintain stable output voltage despite variations in leakage inductance caused by mechanical and electrical tolerances.
2Reliability
If a rotary transmitter is installed to measure and transmit feedback signals from the secondary side to the primary side, then output voltage can be controlled, but additional costs and space requirements are incurred
Solution Approach 1:
The patent extracts the feedback measurement function from the rotating side and relocates it to the stationary side. By measuring the resonance frequency from the stationary primary side and calculating compensation values there, the system eliminates the need for a rotary transmitter to transmit feedback signals, reducing mechanical complexity while maintaining voltage control.
Solution Approach 2:
The patent replaces the mechanical rotary transmitter system with an electrical measurement and calculation system. Instead of using a rotary transmitter to physically transmit feedback signals across the air gap, the system uses electrical resonance frequency measurements and computational algorithms to achieve the same control objective without mechanical moving parts.
3Reliability
If an additional converter stage is installed on the rotating side to maintain constant output voltage, then voltage stability is improved, but costs, weight and volume increase
Solution Approach 1:
The patent performs preliminary measurement of the resonance frequency and calculates the compensation value before power transmission begins. This advance preparation allows the system to set the correct operating frequency to compensate for tolerances, eliminating the need for additional converter stages on the rotating side that would be required to correct voltage deviations during operation.
Solution Approach 2:
The patent enables the series resonant circuit to self-compensate for tolerance effects through frequency adjustment. By measuring the actual resonance frequency and calculating the appropriate frequency deviation, the system allows the resonant circuit to maintain stable output voltage through its own characteristics without requiring external converter stages or additional heavy equipment on the rotating side.
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 ensures a stable output voltage across varying mechanical and electrical tolerances without additional components, reducing costs and complexity by controlling the power generator based on measured resonance frequencies.
Implementation Method 1
a series capacitance is connected in series to compensate. This results in a series resonant circuit. This has an impedance of zero at its resonant frequency and enables the transmission of large amounts of power here
Implementation Method 2
An alternating current is fed into a first winding and tapped off again via a second winding that is movable in relation to this
Data Source
Figure 1~3
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Figure 6~7
AI summary
The invention relates to a method for compensating system tolerances in an inductive coupler. This coupler includes a power generator that feeds an alternating voltage into a series resonant circuit consisting of a resonant capacitor and an inductive rotary transformer. First, a short sequence of at least one period of an alternating voltage is fed into the series resonant circuit by the power generator. The series resonant circuit is then short-circuited. A first resonant frequency is measured. Next, a longer sequence of several periods of an alternating voltage is generated by the power generator, so that a predetermined, small voltage is applied to the load. With the resonant circuit short-circuited, a second resonant frequency is then measured. At least one control variable for the power generator is then determined from these two resonant frequencies.