Impedance Matching Device Dynamic Switch Cycle Control
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Solution Overview
Problem
High-frequency impedance matching devices generate excessive heat due to frequent on-off operations of semiconductor switches when adjusting to varying load impedances, such as in plasma loads, leading to increased switching losses.
Innovation Solution
An impedance matching device that adjusts the states of semiconductor switches based on a reflection coefficient, using a first cycle for rough adjustments when the reflection coefficient is high and a longer second cycle for precise adjustments when it's low, reducing the frequency of switch operations and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous updating of semiconductor switch states is performed to track load impedance variations, then impedance matching precision is improved, but heat generation due to switching loss increases
Solution Approach 1:
The patent applies dynamic update cycle adjustment by switching between a first update cycle (for rapid impedance changes) and a second update cycle (for stable impedance conditions). The control unit determines which cycle to use based on whether the load impedance is changing rapidly or remains stable, thereby optimizing both response speed and energy efficiency in different operating conditions.
Solution Approach 2:
The patent changes the parameter of update cycle duration based on the operating state. When the load impedance is stable, the system transitions to a longer second update cycle, reducing the frequency of switch state updates and minimizing switching losses while maintaining adequate impedance matching precision.
2Adaptability or versatility
If frequent switch operations are performed to adapt to varying load impedance, then adaptability is improved, but heat generation increases
Solution Approach 1:
The patent implements periodic action with variable periods by using two different update cycles. The first update cycle is used when rapid adaptation is needed, while the second update cycle is used when the load impedance is stable. This periodic approach with adaptive period length maintains adaptability while reducing unnecessary frequent operations that cause heat generation.
3Speed
If fast update cycle is used for precise impedance matching, then matching speed is improved, but switching frequency increases causing more heat
Solution Approach 1:
The system dynamically adjusts the update cycle speed based on the actual impedance matching needs. When the load impedance changes rapidly, the first (faster) update cycle is used to maintain matching speed. When the impedance is stable, the system switches to the second (slower) update cycle, reducing switching operation frequency and heat generation while maintaining adequate matching performance.
Data Source
AI summary
An impedance matching device comprises a variable capacitor including multiple capacitance elements and connected in parallel having capacitors and each having one end connected in series to a high-frequency power source and semiconductor switches and connected to the respective capacitors, and a control unit. The control unit derives a reflection coefficient based on the obtained information concerning an impedance viewed from the high-frequency power source toward the load side, updates the states of the respective semiconductor switches and included in the multiple capacitance elements and with a first cycle in the case where the reflection coefficient is equal to or more than a predetermined value, and updates the states of the respective semiconductor switches and included in the plurality of capacitance elements and with a second cycle longer than the first cycle in the case where the reflection coefficient is less than the predetermined value.