Predictive Plasma Power Control for Asynchronous Actuators
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Solution Overview
Problem
Existing plasma processing systems face challenges in controlling actuators due to differential response times and asynchronous operations, leading to inefficiencies and premature system failure, particularly in achieving precise and consistent power delivery in plasma processing.
Innovation Solution
A predictive control system that utilizes a user interface, sensors, and a predictive control section to calculate internal control signals and adjust actuators based on internal models, allowing for advanced anticipation of actuator responses and minimizing energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rail voltage is held at a high level for much of a pulse cycle to ensure sufficient power for fast actuators, then the power delivery reliability is improved, but energy waste increases and components overheat
Solution Approach 1:
The control system predicts future power requirements based on the waveform pattern and actuator response characteristics, adjusting the rail voltage in advance before the actual power demand occurs. This allows the system to prepare the DC rail at optimal levels rather than maintaining continuously high voltage, reducing energy waste while ensuring power availability when needed.
Solution Approach 2:
The system dynamically adjusts the DC rail voltage based on real-time requirements by coordinating fast and slow actuators with different response times. The control algorithm optimizes the voltage level continuously throughout the pulse cycle, raising it only when and where needed for each specific actuator, rather than maintaining a static high voltage level across the entire system.
2Manufacturing precision
If fast actuators are controlled with high precision timing, then manufacturing precision is improved, but the complexity of coordinating multiple actuators with different response times increases
Solution Approach 1:
The control system segments the actuator coordination problem by treating fast and slow actuators separately with dedicated control algorithms for each. The predictive control divides the waveform into segments that account for different actuator response characteristics, allowing precise control of each actuator type without requiring complex inter-coordination logic between them.
Solution Approach 2:
The system performs preliminary characterization of each actuator's response time and behavior during setup, storing this information for use during operation. This pre-established knowledge base allows the control algorithm to automatically compensate for timing differences between actuators without requiring real-time complex calculations or coordination overhead during actual plasma processing.
3Reliability
If the DC section responds slowly to changes in target voltage, then component stress is reduced, but the system cannot achieve rapid power level transitions
Solution Approach 1:
The control system predicts when the DC rail will need to change voltage levels based on the waveform pattern and actuator response characteristics, initiating the voltage transition in advance before the actual power demand occurs. This timing optimization allows the slow DC section to operate at its natural response speed while still meeting the overall power delivery requirements, preventing both overheating and missed transitions.
Data Source
AI summary
This disclosure describes systems, methods, and apparatus for adjusting at least one actuator using at least one control output value to control a plasma processing system. More specifically, the controlling is based on receiving a reference signal defining target values for a parameter that is controlled at an output within the plasma processing system; obtaining a measure of the parameter, where the parameter is measured at a first sampling frequency; calculating one or more internal control signal values at a second sampling frequency; predicting, using an internal model, one or more internal measurements of the controlled parameter at the second sampling frequency; and adjusting, based upon the one or more control output values, at least one actuator at the first sampling frequency, where the control output values are based on the internal control signal values and the predicted internal measurements.