Centrifuge Compressor Motor Feedback Control for Temperature Pulsation
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Solution Overview
Problem
Existing centrifuges face challenges in achieving high-precision temperature control and reducing rotor temperature pulsation due to ON-OFF compressor motor control, especially when windage loss is small, and struggle to maintain consistent performance across varying power supply conditions.
Innovation Solution
A centrifuge design incorporating a control device that uses feedback from a temperature sensor to adjust the compressor motor's speed and operation mode, employing PID calculations and intermittent ON-OFF control to maintain target temperatures, and includes a bypass line and valve system to manage refrigerant flow and prevent excessive rotor temperature drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ON-OFF control is used for compressor motor, then power consumption is reduced and device complexity is lowered, but temperature control precision deteriorates and temperature pulsation increases
Solution Approach 1:
The patent implements feedback control by using a temperature sensor to detect rotor temperature and adjusting compressor motor operation accordingly. The control device receives temperature information and modulates compressor runtime or speed to maintain target temperature, eliminating the temperature pulsation caused by simple ON-OFF control while keeping the system relatively simple.
Solution Approach 2:
The patent transitions from static ON-OFF control to dynamic control by continuously adjusting compressor motor operation based on real-time temperature feedback. This allows the system to adapt compressor runtime and speed dynamically, maintaining precise temperature control without excessive complexity.
2Measurement precision
If compressor motor runs continuously at high speed, then temperature control precision is improved, but power consumption increases and loss of energy worsens
Solution Approach 1:
The control device dynamically adjusts compressor motor speed and runtime based on real-time temperature feedback, allowing the motor to operate at optimal speeds rather than continuously at high speed. This maintains precise temperature control while significantly reducing energy consumption and losses.
Solution Approach 2:
The patent changes operational parameters (compressor speed, runtime) based on temperature conditions. Instead of fixed high-speed operation, the system varies these parameters dynamically, maintaining temperature precision while optimizing energy efficiency and reducing power consumption.
3Measurement precision
If variable speed control is implemented for compressor motor, then temperature control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses feedback control with temperature sensing to justify the variable speed control implementation. The feedback mechanism provides the necessary information to optimize temperature precision, making the increased device complexity worthwhile by achieving superior temperature control compared to fixed-speed systems.
4Loss of energy
If compressor motor is controlled to reduce power consumption, then energy efficiency is improved, but temperature control reliability deteriorates
Solution Approach 1:
The feedback control system ensures temperature control reliability even when compressor motor operates at reduced power consumption levels. By continuously monitoring temperature and adjusting compressor operation accordingly, the system maintains reliable temperature control while improving energy efficiency.
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 configuration enables high-precision temperature control, reduces rotor temperature pulsation, and ensures efficient operation across different power supply conditions, maintaining optimal performance and extending compressor lifespan.
Implementation Method 1
a temperature sensor configured to detect the temperature of the rotor
Implementation Method 2
a compressor configured to compress a refrigerant
Implementation Method 3
an evaporator configured to cool the rotor by vaporizing a refrigerant
Implementation Method 4
cool the rotor by vaporizing a refrigerant
Implementation Method 5
the control device carries out a feedback control of the compressor motor based on a preset temperature and a detected temperature of the temperature sensor
Data Source
AI summary
A centrifuge including: a rotor configured to be driven by a motor and to hold a sample, a centrifuge inverter, a chamber accommodating the rotor, a temperature sensor configured to detect the temperature of the chamber, a cooling machine configured to cool the chamber and including a compressor, a compressor inverter, a compressor motor configured to be controlled in a variable speed and a control device, wherein the control device carries out a feedback control of the compressor motor based on a preset temperature and a detected temperature of the temperature sensor when the rotation number of the compressor motor is larger than a predetermined rotation number, and the control device carries out an intermittent control for turning ON-OFF the cooling function of the compressor when the rotation number of the compressor motor is smaller than a predetermined rotation number.