Integrated control system of screw compressor
By combining a servo control system and a PID controller, precise pressure control and energy optimization of the screw compressor are achieved, solving the problems of mechanical shock and energy waste in traditional screw compressors when gas consumption fluctuates, and improving equipment life and power grid stability.
Patent Information
- Application Number
- CN202520599937.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-04-01
AI Technical Summary
Traditional screw compressors frequently unload and load when faced with fluctuations in gas consumption, leading to mechanical shock, wear, energy waste, and grid impact. Furthermore, the control methods are not precise enough, affecting equipment lifespan and grid stability.
By employing a servo control system combined with a PID controller, the motor speed is precisely controlled to achieve closed-loop pressure regulation. Combined with a water cooler and secondary compression technology, the compression process is optimized, reducing frequent start-stop cycles and energy loss.
It improves the operating efficiency and energy utilization of screw compressors, reduces mechanical wear and power grid impact, lowers production costs, and ensures that the system operates under stable conditions.
Smart Images
Figure CN223806282U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to compressor control and energy -conserving technical field, especially relates to a screw compressor integrated control system. BACKGROUND
[0002] Traditional screw compressor has significant defects in operation mode and control mode. It works in power frequency state for a long time, and pressure control adopts simple upper and lower limit two-point strategy. When the pressure in the cylinder reaches the set upper limit, the intake valve is closed by oil pressure. When the pressure drops to the lower limit, the intake valve is opened. This simple control method is not satisfactory in the face of frequent fluctuations in gas consumption in actual production scenarios, causing the screw compressor to have to unload and load frequently. This not only brings serious mechanical impact and excessive wear to the motor and screw compressor itself, greatly reducing the service life of the equipment, but also has a strong impact on the power grid, seriously damaging the stability of the power grid. More importantly, during the unloading operation stage, the screw compressor stops producing compressed air, but the motor is still in the no-load power consumption state, causing a large amount of electric energy to be wasted, greatly increasing the production cost of enterprises. SUMMARY
[0003] The utility model aims at breaking through the limitation of prior art, and constructs a kind of middle and large screw compressor energy-saving control system of accurate control, high efficiency energy saving, stable and reliable, realizes the optimized operation to screw compressor, improves energy utilization, to meet the above requirements, the utility model provides a kind of screw compressor integrated control system.
[0004] The utility model is realized as follows: a kind of screw compressor integrated control system includes: servo control system, double screw compressor, water cooler, gas storage tank, pressure protection switch and display disc and other key components.
[0005] Servo control system includes: input end: receiving from pressure protection switch, user set signal (such as air pressure demand) and sensor feedback signal (such as exhaust pressure, temperature). Output end: control the servo motor speed of double screw compressor and start-stop. Communication interface: data interaction is carried out with display disc, PLC or host computer. Servo control system adjusts motor speed in real time by PID regulator algorithm, matches gas consumption change, reduces frequent start-stop loss.
[0006] Double screw compressor: direct connection with servo motor through shaft coupling, driven yin and yang rotor rotation by servo system, air inlet connects air cleaner, and exhaust port is connected with water cooler inlet through check valve.
[0007] Water cooler: input end: receiving high-temperature compressed gas discharged by double screw compressor. Output end: cooled gas is delivered to gas storage tank inlet. Cooling medium: circulating cooling water is connected with external water chiller through pipeline.
[0008] Gas tank: input: connected to the outlet of the water cooler, store the cooled compressed gas. Output: through the pipeline to the gas equipment, and connected to the pressure protection switch to monitor the tank pressure.
[0009] Pressure protection switch: installed in the gas tank or main pipeline, set the upper and lower pressure threshold, overpressure triggered pressure protection.
[0010] Display panel for receiving real-time data from servo control system, pressure protection switch, temperature sensor, etc. Display pressure, temperature, running status, fault code and other information.
[0011] Servo control system as the core control hub of the whole system, undertake the precise control of the system running state of the heavy responsibility. Through the careful design of electrical connection and high-speed signal transmission path between the components, realize the close no gap of collaborative work. Pressure sensor is precisely installed on the gas tank, and a high-speed, stable data transmission link is established between the servo control system, real-time acquisition of pressure signal and rapid conversion to electrical signal transmission to the servo control system servo control system and the driving motor of the double screw compressor using advanced control technology to achieve precise electrical connection, according to the received signal, control motor speed, so as to realize the all-round regulation of screw compressor working state. Water cooler and screw compressor are closely coupled to form a heat dissipation circuit, which can remove the heat generated during the compression process in time, ensuring that the system always runs in a stable temperature environment. The system has intelligent power frequency / variable frequency interlock switching function, which can select the appropriate operation mode according to the actual working condition demand, effectively ensure the continuity and stability of the production process.
[0012] The servo control system adopts advanced pressure closed-loop regulation technology to realize the control of the gas supply pressure. The pressure sensor collects the pressure signal in the pressure tank and converts it into an accurate electric signal, which is transmitted to the PID regulator. The PID regulator uses advanced proportional (P), integral (I), and differential (D) algorithms to compare and operate the received pressure signal with the preset pressure set value, and outputs a control signal. The PID regulator relies on the driving circuit to change the motor speed according to the signal output frequency. When the actual pressure is lower than the set pressure, the PID regulator calculates the appropriate adjustment amount, the PID regulator increases the output frequency, the motor speed increases, and the gas supply of the screw compressor is increased in time to make the pressure return to the set value; conversely, when the actual pressure is higher than the set pressure, the motor speed is reduced, and the gas supply is reduced to ensure that the pressure always operates within the set range. This pressure control mechanism effectively eliminates the frequent unloading and loading phenomenon caused by pressure fluctuations in the traditional control method, allowing the screw compressor to operate stably in an efficient and energy-saving state. At the same time, stable pressure control allows users to use the unit at a lower and stable pressure, and can configure a smaller gas tank according to actual needs, further optimizing the overall configuration of the system and reducing equipment costs.
[0013] The working process of the screw compressor involves isothermal, adiabatic, and polytropic three compression theory working cycles. Under the same suction end state, the gas is compressed to the same final pressure according to different rules (isothermal, adiabatic, and polytropic). The isothermal compression consumes the least power, the adiabatic compression consumes the most power, and the polytropic compression is between the two. In practice, the excellent heat dissipation performance of the water cooler is combined with the precise adjustment of the motor speed by the servo control system to control the compression process. The PID regulator adjusts the motor speed according to the real-time feedback signals from the pressure and temperature sensors to control the compression ratio and gas flow rate, making the compression process as close to the isothermal compression state as possible. During the compression process, when the temperature sensor detects a temperature rise trend, the PID regulator immediately reduces the motor speed to slow down the compression speed, while the water cooler increases the heat dissipation intensity to ensure that the temperature does not rise excessively, effectively reducing the energy loss caused by adiabatic or polytropic compression, thereby reducing power consumption and improving work efficiency.
[0014] The screw compressor of the system adopts a two-stage compression technology to further improve energy saving. After the first compression, the gas is subjected to targeted intermediate treatment before entering the second compression stage. The use of two-stage compression technology can save more than 10% of energy for the screw compressor.
[0015] The servo control system is composed of various key electrical components, including air switch QF1, soft starter, intermediate relay KJ1, contactors KM1 and KM2, PID regulator, etc. The power supply circuit provides stable and reliable power for the entire system, and the control loop realizes precise control over each component. The operation buttons such as QS1 (start button), QS2 (stop button), SB1 (servo start button), SB2 (servo stop button) realize the selection and control of the power frequency / variable frequency operation mode under the control logic through the cooperation of intermediate relay KJ1, contactors KM1 and KM2, etc. The PID regulator, as the core of the electric control system, receives signals collected by various sensors such as pressure sensor and temperature sensor, performs real-time operation and processing, and outputs precise control signals to accurately adjust the motor speed, thereby realizing energy-saving control of the screw compressor. At the same time, the system is equipped with perfect fault detection and protection logic, such as overcurrent protection and overvoltage protection, which realizes real-time monitoring and response of the system operating state through corresponding sensitive electrical components. Once an abnormal condition is detected, the system immediately takes protective measures to ensure safe and stable operation of the system under various working conditions, avoiding equipment damage and production accidents.
[0016] The utility model discloses the beneficial effect is: accurate pressure control energy saving, when facing complex gas working condition, such as plastic processing or rubber product production industry, gas demand often presents complex fluctuation. When the gas consumption reduces, the servo control system can reduce the motor speed through the PID regulator when applying the utility model control system, avoid the screw compressor in traditional control mode because of pressure upper limit reaches and completely stops the air (unloading) situation, improves the operating efficiency energy saving. 2, reduce the power grid impact energy saving, through the stable motor operation, reduce the unloading loading times, effectively reduce the impact on the power grid. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 It is the structure schematic diagram of the utility model;
[0018] Figure 2 It is the structure schematic diagram of the utility model servo control system main circuit diagram;
[0019] Figure 3 It is the structure schematic diagram of the utility model servo control system control circuit diagram;
[0020] In the drawing: 1 - double screw compressor, 2 - water cooler, 3 - gas storage tank, 4 - gas equipment, 5 - servo control system, 6 - display disc, 7 - pressure sensor, 8 - temperature sensor, 9 - pressure protection switch, 10 - PID regulator. DETAILED DESCRIPTION
[0021] In order to make the technical scheme of the utility model more clearly understood, the utility model will be further described below with reference to the drawings.
[0022] As Figures 1-3 shown in a kind of screw compressor integrated control system, as Figure 1 shown, including servo control system 5, double screw compressor 1, water cooler 2, gas tank 3, pressure protection switch 9 and display disc 6, the gas tank 3 is provided with pressure sensor 7 and temperature sensor 8, servo control system 5 includes PID regulator 10, and pressure sensor 7 real-time feedback data to PID regulator 10, the servo control system 5 is adjusted by PID regulator 10 the drive motor speed of double screw compressor 1 in real time, matches the gas consumption variation, the double screw compressor 1 generates compressed gas, and compressed gas enters gas tank through water cooler 2, the gas tank 3 is connected with gas equipment 4, the gas tank 3 is provided with pressure protection switch 9 on the pipeline of gas equipment, and the display disc 6 is connected pressure sensor 7, temperature sensor 8, the drive motor of double screw compressor, water cooler 2 and pressure protection switch 9.
[0023] Working principle: 1. starting stage: user sets the air pressure demand (such as 0.8MPa), and pressure sensor detects that the pressure of gas tank is lower than lower limit (0.7MPa), sends starting signal to servo control system.PID regulator 10 is adjusted according to the demand of servo control system and the motor speed of double screw compressor, and the sun and moon rotors start to rotate at low speed, and gradually improve the exhaust volume.2. compression and cooling: air enters double screw compressor after being filtered, and the sun and moon rotors mesh to compress gas to high pressure state (such as 1.0MPa). High-temperature gas enters water cooler and is cooled by circulating cooling water.3. pressure dynamic adjustment: when the pressure of gas tank reaches upper limit (1.0MPa), frequency reduction or shutdown is triggered for servo control system; when the pressure drops, it is automatically restarted.Servo control system adjusts the motor speed in real time through PID algorithm, matches the gas consumption variation, and reduces the loss of frequent start and stop.4. safety protection and monitoring: pressure sensor continuously monitors pressure, and pressure protection switch triggers forced power cut-off and alarm when abnormal overpressure occurs.Display disc real-time feedback pressure, temperature, current and other parameters.Servo control system dynamically adjusts compression ratio according to load, reduces no-load energy consumption; gas tank buffers pressure fluctuation, reduces the start and stop frequency of compressor.
[0024] The servo control system includes main circuit and control circuit, as Figure 2The main circuit shown includes an air switch QF1, which is connected to a servo power supply. The servo power supply is connected to a motor circuit and also to a frequency converter. The motor circuit is also connected to a soft starter. The power supply side of the main circuit is connected through the air switch QF1. The three-phase live wires L1, L2, and L3 and the neutral wire N1 are introduced into the servo control system. The soft starter is connected to the three-phase live wires L1, L2, and L3, and its output is connected to the contactor KM2. In the servo power supply, R, S, and T are input interfaces connected to the three-phase live wires L1, L2, and L3. The output terminals U, V, and W of the servo power supply are connected to the drive motor M of the twin-screw compressor through the contactor KM1. The output current of the motor circuit is detected by current transformers TA1, TA2, and TA3.
[0025] like Figure 3 The control circuit shown includes a control relay KJ1 circuit and a main contactor circuit. The main contactor includes a contactor KM1 control circuit, a contactor KM2 control circuit, and a signal output circuit. The control circuit power supply is 380V~, introduced through L1 and L2. The control circuit power supply includes a stop button QS2 and a start button QS1. The start button QS1 and stop button QS2 are used to control the energization and de-energization of the KJ1 relay. When the stop button QS2 is closed (here, the closure is a self-locking closure) and the start button QS1 is closed, the coil of the KJ1 relay is energized, and its normally open contact closes, achieving self-locking. The stop button QS2, start button QS1, and relay KJ1 constitute the control logic. The control circuit includes a servo start button SB1 and a servo stop button SB2, which control the on / off state of contactors KM1 and KM2. The control logic for contactor KM1 is as follows: When the servo start button SB1 is pressed, with the normally open contact of KJ1 closed and the normally closed contact of KM2 closed, the coil of KM1 is energized, and the servo control system powers the drive motor of the twin-screw compressor. The control logic for contactor KM2 is as follows: When the normally open contact of KJ1 is closed and the normally closed contact of KM1 is closed, the pressure sensor feeds back data to the PID controller. The PID controller processes the pressure sensor feedback data and controls the coil of contactor KM2 to be energized or de-energized. When the pressure sensor feedback data meets the conditions, the coil of KM2 is energized, the main contact of KM2 closes, and the motor enters the mains frequency operation mode. The signal output circuit control logic is as follows: the auxiliary contact of contactor KM1 is used to control the servo power-on indicator light, the auxiliary contact of contactor KM2 is used to control the power frequency operation indicator light, the contacts of KJ1 and KM1 are connected to the DCOM and DI11 interfaces for external control or signal feedback, after the normally open contact of KM1 is closed, the "servo power-on" signal is output; after the normally open contact of KM2 is closed, the "power frequency operation" signal is output; the normally open contacts of KJ1 and KM1 are connected in series to DCOM and DI1 for feedback status signals.
[0026] Circuit control principle: 1. Servo start: first close QS2, QS1, KJ1 relay power self-locking. Press SB1, KM1 power, servo control system to screw compressor drive motor power supply, drive motor in servo mode operation, while output servo power signal. 2. Frequency switching: when switching to the power frequency operation, first stop servo operation (SB2 is disconnected), KM1 power, its normally closed contact is closed, the pressure sensor feedback data to the PID regulator, the PID regulator will pressure sensor feedback data processing control contactor KM2 coil power or power off, pressure sensor feedback data to meet the conditions, KM2 power, the motor is switched to the power frequency operation mode, output power frequency operation signal. Fault protection: when the servo system fails, the fault indicator light, prompting the operator to handle. At the same time, the current transformer to monitor the motor current, the motor can be overloaded and other protection.
[0027] The screw compressor integrated control system of the utility model is suitable for the industry needing stable gas source such as pneumatic manufacturing, food packaging, mine machinery, realizes high efficiency, low noise and long service life operation through closed loop control.
[0028] The above is only the preferred embodiment of the utility model, therefore, equivalent changes or modifications made according to the structure, features and principles described in the utility model patent application range are included in the utility model patent application range.
Claims
1. A screw compressor integrated control system, comprising a servo control system, a double screw compressor, a water cooler, a gas storage tank, a pressure protection switch and a display panel, characterized in that, the gas storage tank is provided with a pressure sensor and a temperature sensor, the servo control system comprises a PID regulator, the pressure sensor feeds data to the PID regulator in real time, and the servo control system adjusts the rotating speed of the driving motor of the double screw compressor through the PID regulator to match the change in gas consumption, the double screw compressor produces compressed gas, the compressed gas enters the gas storage tank through the water cooler, the gas storage tank is connected to a gas-consuming device, and the pressure protection switch is arranged on the pipeline connecting the gas-consuming device, the display panel is connected to the pressure sensor, the temperature sensor, the driving motor of the double screw compressor, the water cooler and the pressure protection switch.
2. A screw compressor integrated control system according to claim 1, characterized in that the servo control system comprises a main circuit and a control circuit, the main circuit comprises an air switch QF1, the air switch QF1 is connected to a servo power supply, the servo power supply is connected to a motor circuit, the servo power supply is also connected to a frequency converter, and the motor circuit is also connected to a soft starter, the control circuit comprises a control relay KJ1 circuit and a main contactor circuit, and the main contactor comprises a contactor KM1 control circuit, a contactor KM2 control circuit and a signal output circuit.
3. A screw compressor integrated control system according to claim 2, characterized in that The power supply side of the main circuit is connected through the air switch QF1, the three-phase live wire L1, L2, L3 and the zero line N1 are introduced into the servo control system, the soft starter is connected to the three-phase live wire L1, L2, L3, and the output is connected to the contactor KM2. In the servo power supply, R, S and T are input interfaces connected to the three-phase live wire L1, L2, L3, and the output terminals U, V and W of the servo power supply are connected to the driving motor M of the double screw compressor through the contactor KM1. The motor circuit output current is detected by current transformers TA1, TA2 and TA3.
4. The integrated control system of a screw compressor according to claim 2, characterized in that, The control circuit power supply is 380V~ introduced by L1 and L2, and the control circuit power supply includes a stop button QS2 and a start button QS1. The start button QS1 and the stop button QS2 are used to control the power-on and power-off of the KJ1 relay. When the stop button QS2 is closed and the start button QS1 is closed, the KJ1 relay coil is powered on, the normally open contact is closed, and self-locking is realized. The stop button QS2, the start button QS1 and the relay KJ1 constitute the control logic.
5. The integrated control system of a screw compressor according to claim 2, wherein The control circuit comprises a servo start button SB1 and a servo stop button SB2, which are used to control the on-off of the contactors KM1 and KM2. Contactor KM1 control logic: press the servo start button SB1, and in the case that the KJ1 normally open contact is closed and the KM2 normally closed contact is closed, the KM1 coil is powered on, and the servo control system powers on the driving motor of the double screw compressor, Contactor KM2 control logic: when KJ1 normally open contact is closed and KM1 normally closed contact is closed, the pressure sensor feedback data to the PID regulator, the PID regulator will process the pressure sensor feedback data to control the contactor KM2 coil power or loss, when the pressure sensor feedback data meet the conditions, KM2 coil power, KM2 main contact is closed, the motor into the power frequency operation mode.
6. The integrated control system of a screw compressor according to claim 2, wherein The signal output circuit control logic is as follows: the auxiliary contact of the contactor KM1 is used to control the servo power-on indicator light, the auxiliary contact of the contactor KM2 is used to control the power frequency operation indicator light, the contacts of KJ1 and KM1 are connected to DCOM and DI11 interface for external control or signal feedback, after the normally open contact of KM1 is closed, the "servo power-on" signal is output; after the normally open contact of KM2 is closed, the "power frequency operation" signal is output; the normally open contacts of KJ1 and KM1 are connected in series to DCOM and DI1 for feedback state signal.