Wireless Power Control System Phase Shift Noise Reduction
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Solution Overview
Problem
Existing wireless motor drive systems face challenges in accurately controlling the voltage applied to motors, particularly in semiconductor exposure apparatuses, due to switching noise generated in the power transmission side, which affects the precision of motor positioning and voltage accuracy.
Innovation Solution
A control system that includes a phase shift unit to provide a phase difference between switching clock signals, a power transmission coil, a switching circuit, a power reception coil, and a rectifier circuit, which wirelessly transmits electric power and adjusts the phase difference to minimize switching noise and ensure accurate voltage application to the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireless power transmission is implemented to eliminate power supply cables, then the positioning accuracy of the stage is improved, but switching noise is generated in the power transmission circuit
Solution Approach 1:
A phase shift unit is introduced as an intermediary component between the switching circuit and the power reception coil. This phase shift unit adjusts the phase of the switching clock signal to create a phase difference, which serves as a mediator to reduce the harmful switching noise while maintaining the wireless power transmission function.
Solution Approach 2:
The phase of the switching clock signal is changed as a key parameter to reduce switching noise. The phase shift unit varies the phase parameter of the switching clock signal to create an optimal phase difference between the switched voltage and the clock signal, thereby minimizing noise generation while maintaining power transmission efficiency.
2Power
If switching circuit is used to control voltage applied to motor, then power transmission efficiency is improved, but switching noise affects voltage accuracy
Solution Approach 1:
The phase shift unit acts as an intermediary between the switching circuit and the power reception coil, introducing a phase difference that reduces the coupling of switching noise into the power transmission path. This allows the switching circuit to maintain high power transmission efficiency while reducing noise interference with voltage accuracy.
Solution Approach 2:
The switching noise, which is inherently generated by the switching circuit, is converted into a beneficial effect by introducing a phase difference. The phase-shifted switching clock signal causes the switching noise to occur at different timing, reducing its impact on voltage accuracy while maintaining the necessary switching operation for efficient power transmission.
3Object-generated harmful factors
If phase difference is introduced between switching clock signals, then switching noise is reduced, but device complexity increases
Solution Approach 1:
A dedicated phase shift unit is introduced as an intermediary component to generate the phase difference between switching clock signals. This separate module simplifies the overall system architecture by concentrating the phase adjustment function in a dedicated unit, making the noise reduction mechanism more manageable despite adding a component.
Solution Approach 2:
The phase shift unit serves multiple functions: it generates the phase difference to reduce switching noise, maintains synchronization between transmitting and receiving sides, and enables precise control of the switching timing. This multi-functionality justifies the added complexity by providing several benefits from a single component.
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
The system effectively reduces switching noise, allowing for precise control of motor voltage, enabling high-accuracy positioning and operation of motors with minute voltage applications, such as in semiconductor exposure apparatuses.
Implementation Method 1
a power reception coil configured to receive electric power output from the power transmission coil by electromagnetic field coupling
Data Source
AI summary
A control system includes a phase shift unit configured to provide a phase difference between a first switching clock signal and a second switching clock signal, a power transmission coil, a switching circuit configured to switch an input voltage based on the first switching clock signal and apply the switched voltage to the power transmission coil, a power reception coil configured to receive electric power output from the power transmission coil by electromagnetic field coupling, a wireless transmission unit configured to wirelessly transmit the second switching clock signal and output a third switching clock signal, and a rectifier circuit configured to rectify a voltage input from the power reception coil by switching the voltage based on the third switching clock signal and apply the rectified voltage to a load. A voltage input from the power reception coil to the rectifier circuit and the third switching clock signal have different phases.