Wireless Power Coil Switching for High-Speed Motor Control
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Solution Overview
Problem
Existing wireless motor control systems face challenges in achieving high-speed and accurate motor control due to delays in wireless communication, which limit the precision of voltage application to motors, especially in applications like semiconductor exposure apparatuses.
Innovation Solution
A wireless device comprising a power transmission coil, a power reception coil, a switch circuit, and a rectification circuit with bidirectional switches, which enables contactless power transmission and synchronization of switching signals to accurately control motor voltage, eliminating the need for conventional PWM signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless communication using radio waves is used to transmit control signals to the motor driving circuit, then the motor can be driven wirelessly, but the control speed is limited due to communication delays of several hundred μs to several milliseconds
Solution Approach 1:
The system separates power transmission and control signal transmission into different channels: power is transmitted wirelessly through electromagnetic coupling between coils, while control signals are transmitted through wired connections. This segmentation allows high-speed control signals to be sent without the delays inherent in wireless radio communication, while still maintaining wireless power transmission for ease of operation.
Solution Approach 2:
The patent introduces a power transmission coil and power reception coil as intermediaries to enable wireless power transmission. The control signal transmission unit then uses these coils along with wired connections to transmit control signals, bypassing the need for slow wireless radio communication while maintaining the benefit of wireless power transmission.
2Manufacturing precision
If control signals are transmitted at a period of several hundred microseconds or less to achieve high-speed motor control, then positioning accuracy improves, but wireless communication delays prevent achieving this control speed
Solution Approach 1:
The system divides the control architecture into two parts: high-speed control signals transmitted through wired connections for precise timing, and wireless power transmission for convenience. This allows the control period to be reduced to several hundred microseconds or less for high positioning accuracy, while the wireless power transmission operates independently without contributing to control delays.
Solution Approach 2:
The patent replaces the wireless radio communication mechanism with a wired signal transmission mechanism for control signals. This substitution eliminates the propagation delays and interference issues of wireless communication, enabling high-speed control signal transmission at periods of several hundred microseconds or less, thereby achieving high positioning accuracy.
3Use of energy by moving object
If a cable is moved with the stage to feed power to the motor, then power can be supplied to the moving motor, but the cable tension affects stage positioning accuracy
Solution Approach 1:
The patent replaces the mechanical cable-based power transmission system with an electromagnetic wireless power transmission system using power transmission coils and power reception coils. This substitution eliminates the physical cable that caused tension and positioning errors, while still providing continuous power supply to the moving motor. The wireless power transmission operates through electromagnetic coupling without mechanical constraints.
Solution Approach 2:
The patent extracts and removes the cable from the system by implementing wireless power transmission. The power supply function is maintained through electromagnetic coupling between transmission and reception coils, while the harmful cable tension that affected positioning accuracy is completely eliminated from the movable stage system.
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 allows for high-speed and accurate motor control with reduced circuit size and weight on the movable side, enhancing the precision of voltage application and overcoming the limitations of delayed wireless communication.
Implementation Method 1
a power transmission coil configured to transmit power wirelessly, a power reception coil configured to receive the power wirelessly from the power transmission coil
Data Source
AI summary
A wireless device includes a power transmission coil configured to transmit power wirelessly, a power reception coil configured to receive the power wirelessly, a switch circuit configured to apply a voltage to the power transmission coil based on a first switching signal, and a rectification circuit configured to rectify a voltage output from the power reception coil based on a second switching signal and apply the rectified voltage to a load, wherein the switch circuit and the rectification circuit each include a plurality of bidirectional switches.