Electrostatic Contactless Power Supply with Capacitance Compensation
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Solution Overview
Problem
In electrostatic-coupling contactless power supply devices for substrate working machines, mechanical distortions and machining accuracy limitations cause changes in the distance between power supply and receiving electrode plates, leading to capacitance changes, which can result in reduced power supply efficiency due to frequency deviations and increased switching and skin losses.
Innovation Solution
The device employs a configuration where power supply and receiving electrode plates form capacitors that compensate for each other's capacitance changes when the movable portion's position relative to the static portion changes, using a high-frequency power source circuit that adjusts output frequency to maintain resonant frequency stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power supply and receiving electrode plates are disposed facing each other with spacing to form capacitors, then contactless power supply is achieved, but mechanical distortions and machining accuracy limitations cause distance changes leading to capacitance variations
Solution Approach 1:
The power supply system is divided into multiple capacitor units formed by pairs of electrode plates. By segmenting the single capacitor into multiple capacitors, the system can compensate for distance variations through the combined effect of multiple capacitive elements, reducing the impact of individual distance control inaccuracies.
Solution Approach 2:
The invention utilizes the capacitance parameter of multiple capacitors formed by electrode plate pairs. By controlling and adjusting the capacitance values of individual capacitors, the system can compensate for distance variations and maintain stable overall capacitance, thereby improving power supply reliability despite manufacturing precision limitations.
2Productivity
If capacitance changes occur due to position variations, then resonant frequency deviates, but power supply efficiency is reduced due to increased switching and skin losses
Solution Approach 1:
The invention implements impedance detection and feedback control mechanisms that continuously monitor the capacitance of the electrostatic coupling capacitors. Based on the detected capacitance changes, the system adjusts the resonant frequency to maintain optimal power transfer efficiency and minimize energy losses from switching and skin effects.
Solution Approach 2:
The system dynamically adjusts the resonant frequency in response to capacitance changes caused by position variations. This dynamic adaptation ensures that the power supply operates at optimal efficiency across different operating conditions, preventing energy losses that would occur with fixed frequency operation.
3Reliability
If electromagnetic induction system with coil is used for contactless power supply, then power can be supplied without contact, but weight of the coil increases and magnetic field interferes with linear motor device
Solution Approach 1:
The invention replaces the electromagnetic induction system with a mechanical-electrostatic coupling system using electrode plates. This substitution eliminates the need for heavy coils while avoiding magnetic field interference with the linear motor device, achieving contactless power supply through electrostatic fields instead of electromagnetic fields.
Solution Approach 2:
The invention converts the potential harm of magnetic field interference into a benefit by using electrostatic fields instead. The electrostatic coupling between facing electrode plates provides contactless power supply without the weight and interference problems of electromagnetic coils, turning the design constraint into a system advantage.
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 configuration suppresses capacitance changes in the power supply circuit, maintaining high power supply efficiency by controlling resonant frequency and reducing switching and skin losses, even under mechanical stress or machining accuracy restrictions.
Implementation Method 1
power supply electrode plates 41 to 44 and power receiving electrode plates 61 to 64 face each other so as to be spaced apart from each other, and form capacitors
Implementation Method 2
high-frequency power source circuit 5 that supplies high-frequency power between the plurality of power supply electrode plates
Implementation Method 3
a resonant circuit is generally used in the electrostatic-coupling contactless power supply to ensure a large amount of supplied power
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An electrostatic-coupling contactless power supply device 1 of the invention includes: a plurality of power supply electrode plates 41 to 44 that are provided on a static portion (track member 2) ; a high-frequency power source circuit 5 that supplies high-frequency power between the plurality of power supply electrode plates 41 to 44; a plurality of power receiving electrode plates 61 to 64 that are provided on a movable portion (linear movable portion 3) movably mounted on the static portion 2, face the plurality of power supply electrode plates 41 to 44 so as to be spaced apart from the plurality of power supply electrode plates 41 to 44, respectively, and receive high-frequency power in a contactless manner; and the power receiving circuit 7 that converts the high-frequency power received by the plurality of power receiving electrode plates 61 to 64 and supplies the converted high-frequency power to an electrical load 8 provided on the movable portion 3. When the position of the movable portion 3 relative to the static portion 2 is changed, capacitances C1 to C4 of a plurality of capacitors Cds1 to Cds4, which are formed by the power supply electrode plates 41 to 44 and the power receiving electrode plates 61 to 64 facing each other so as to be spaced apart from each other, are changed so as to compensate each other. Accordingly, since the change of a capacitance is suppressed even though the position of the movable portion 3 relative to the static portion 2 is changed, high power supply efficiency can be maintained.