Gas compressor and method for controlling same
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Solution Overview
Problem
Existing gas compressor control methods experience control delay and pressure undershoot due to unconditional addition of compressor bodies when air demand increases sharply, leading to unnecessary discharge pressure fluctuations.
Innovation Solution
A method that dynamically controls the number of operating compressor bodies by analyzing the pressure value and its temporal changing amount, determining if increasing the driving frequency of each compressor body is possible, and adjusting the number of compressor bodies based on remaining discharge capacity and air demand, using inverter-based rotational speed control to maintain stable discharge pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of operating compressor bodies is unconditionally increased when discharge pressure drops below the lower limit, then the discharge pressure can be restored, but control delay and pressure undershoot occur due to not considering the delay time of pressure increase
Solution Approach 1:
The control device performs preliminary assessment by calculating the required number of compressor bodies based on current discharge pressure and its rate of change before actually increasing the number of operating compressors. This allows the system to anticipate the pressure recovery time and avoid premature or excessive compressor activation, thereby reducing control delay and pressure undershoot while ensuring reliable discharge pressure restoration.
2Reliability
If the number of operating compressor bodies is unconditionally increased when discharge pressure drops below the lower limit, then the discharge pressure can be restored, but unnecessary discharge pressure fluctuations occur due to sharp increases in air demand
Solution Approach 1:
The control device continuously monitors the discharge pressure and its rate of change, using this feedback information to dynamically determine the appropriate number of compressor bodies to operate. By considering both the current pressure level and its temporal变化 rate, the system can make informed decisions about when to increase compressor numbers, avoiding unnecessary pressure fluctuations while maintaining stable discharge pressure.
3Reliability
If inverter-based rotational speed control is used to maintain constant discharge pressure, then pressure control is achieved, but control effectiveness is reduced when air demand increases sharply
Solution Approach 1:
The control system dynamically switches between rotational speed control (using inverters) and number control (adjusting the count of operating compressor bodies) based on real-time discharge pressure conditions and their rate of change. This dynamic adaptation allows the system to maintain effective pressure control under varying air demand conditions, combining the precision of speed control with the responsiveness of number control when needed.
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 approach reduces discharge pressure fluctuations and prevents unnecessary drops in pressure by timely adjustment of compressor body numbers and driving frequencies, ensuring efficient air supply and stable compressor operation.
Implementation Method 1
the compressor includes the plurality of compressor bodies disposed in parallel and subjected to rotational speed control by an inverter
Data Source
Figure 1
Figure 2~3(d)
Figure 4
AI summary
The purpose of the present invention is to provide a gas compressor that can achieve reduced fluctuation of discharge pressure during compressor body number control, and a method for controlling the gas compressor. This gas compressor includes a plurality of compressor units each having a compressor body, a motor for driving the compressor body, and an inverter for controlling a rotational speed of the motor, and a control device for controlling each of the inverters, in which discharge pipes of the compressor bodies are merged with one main discharge pipe and discharge pressure of the main discharge pipe is controlled through control of pressure of the respective discharge pipes by controlling, by means of the respective inverters, driving frequencies of the compressor bodies. The control device determines whether recovery through an increase in the driving frequency of the motor of each of the compressor bodies is possible, on the basis of the pressure value and a temporal changing amount of the discharge pressure of the main discharge pipe when the driving frequency of the motor of the compressor body is being increased but has not reached an upper limit frequency, and controls an increase of the number of the compressor bodies to be operated.