BLDC Pump Piston Position Control via Field-Oriented Feedback
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Solution Overview
Problem
Existing pumping systems in semiconductor manufacturing face challenges in achieving precise and repeatable position control of mechanical pistons, leading to inconsistent fluid dispensing due to pressure variations, vibration, and damage to expensive photochemicals.
Innovation Solution
A motor-driven pumping system utilizing a brushless DC motor (BLDCM) with a digital signal processor (DSP) and field-oriented control (FOC), along with a position sensor for real-time feedback, to provide precise and repeatable position control, reducing heat generation and maintaining constant velocity across a wide range of speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pumping systems are used, then fluid dispensing is performed, but position control of the mechanical piston is imprecise and non-repeatable
Solution Approach 1:
The patent employs a feedback control system where the actual position of the mechanical piston is continuously measured and compared to the desired position, with control signals adjusted based on the position error to achieve precise and repeatable positioning
Solution Approach 2:
The patent replaces conventional mechanical positioning mechanisms with a motor-driven system controlled by digital signal processing and field-oriented control algorithms, enabling precise electronic control of piston position
2Productivity
If pressure control is implemented to compensate for pressure variations, then fluid dispensing consistency improves, but system complexity increases
Solution Approach 1:
The patent implements pressure feedback control where actual pressure is measured and used to adjust motor control parameters, compensating for pressure variations to maintain consistent fluid dispensing
Solution Approach 2:
The patent dynamically adjusts motor control parameters based on measured pressure conditions, changing operational parameters in real-time to compensate for pressure variations and maintain dispensing consistency
3Productivity
If high-speed operation is achieved, then productivity increases, but vibration from the stepper motor adversely affects performance
Solution Approach 1:
The patent replaces the vibration-prone stepper motor with a brushless DC motor controlled by field-oriented control, eliminating mechanical vibration while maintaining high-speed operation capability
Solution Approach 2:
The patent uses periodic control updates at optimized frequencies to maintain smooth motor operation at high speeds while minimizing vibration through controlled periodic actuation
4Power
If pneumatic pumps with solenoids are used, then fluid pumping is achieved, but large pressure spikes occur when the solenoid activates
Solution Approach 1:
The patent replaces the solenoid-actuated pneumatic pump with a motor-driven pump system, eliminating the abrupt solenoid activation that causes pressure spikes while maintaining pumping capability
Solution Approach 2:
The patent implements dynamic control of the motor-driven pump system, allowing smooth acceleration and deceleration of fluid movement to prevent pressure spikes while maintaining effective pumping
5Power
If multiple stage pumps are used, then pumping capability is enhanced, but small operational glitches cause sharp pressure spikes in the liquid
Solution Approach 1:
The patent implements feedback control monitoring the operational state of each pump stage, detecting and compensating for small glitches before they propagate to cause pressure spikes in the liquid
Solution Approach 2:
The patent employs damping and pressure regulation mechanisms that anticipate and cushion against pressure spikes before they occur, protecting the liquid from damage due to operational variations
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 achieves real-time, smooth motion with precise and repeatable control over fluid movements and dispense amounts, minimizing pressure spikes and fluid damage, while optimizing energy use and reducing operational heat.
Implementation Method 1
a motor-driven pump, more specifically a brushless DC motor (BLDCM) with a position sensor
Data Source
AI summary
Embodiments of the systems and methods disclosed herein utilize a brushless DC motor (BLDCM) to drive a single-stage or a multi-stage pump in a pumping system for real time, smooth motion, and extremely precise and repeatable position control over fluid movements and dispense amounts, useful in semiconductor manufacturing. The BLDCM may employ a position sensor for real time position feedback to a processor executing a custom field-oriented control scheme. Embodiments of the invention can reduce heat generation without undesirably compromising the precise position control of the dispense pump by increasing and decreasing, via a custom control scheme, the operating frequency of the BLDCM according to the criticality of the underlying function(s). The control scheme can run the BLDCM at very low speeds while maintaining a constant velocity, which enables the pumping system to operate in a wide range of speeds with minimal variation, substantially increasing dispense performance and operation capabilities.