Direct-current variable-frequency helium compressor without active working bypass structure
By using a DC inverter helium compressor with no active bypass structure, the mechanical structure of the traditional inverter compressor is optimized through the electronic control system and control panel. The one-way valve and variable flow regulating device are eliminated, resulting in cost reduction and efficiency improvement, making it suitable for a variety of working scenarios.
Patent Information
- Application Number
- CN202511420024.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2025-11-21
AI Technical Summary
Traditional variable frequency compressors require a check valve and variable flow regulating device in the bypass pipeline when the pressure is too high, which is complex in mechanical structure and expensive.
Design a DC inverter helium compressor without an active bypass structure. The controlled object is manually switched through the electronic control system and control panel. The one-way valve and variable flow regulating device in the active bypass are eliminated. The pressure is balanced by a passive bypass solenoid valve, combined with high pressure sensor and motor speed control.
It simplifies the mechanical structure, reduces costs, improves efficiency, adapts to various working scenarios, and meets the needs of small and lightweight design.
Smart Images
Figure CN120990845A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of scroll helium compressors, and more particularly to a DC inverter helium compressor without an active working bypass structure. Background Technology
[0002] Scroll compressors are widely used in various air conditioning and refrigeration units, and the scroll compressor pack is an important component of the scroll compressor. Helium, due to its good thermal conductivity and strong chemical inertness, can be used as a cooling medium to improve heat dissipation efficiency. Scroll compressors can also be used to compress helium; the compressed helium is then introduced into the refrigeration unit for efficient cooling. The stator of a DC inverter motor uses three-phase winding coils, which generate a rotating magnetic field when energized. The rotor is composed of high-performance permanent magnets, which drive rotation through interaction with the stator. Compared to traditional three-phase asynchronous motors, this improves efficiency by 8%-10%.
[0003] However, traditional variable frequency compressors have a single control mode and require a one-way valve and variable flow regulating device in the bypass pipeline for active bypass pressure relief when the pressure is too high. This results in a complex mechanical structure and high operating costs.
[0004] Therefore, it is necessary to develop a new type of DC inverter helium compressor to overcome the above problems. Summary of the Invention
[0005] Purpose of the invention: To address the shortcomings and defects of existing technologies, this invention provides a DC inverter helium compressor with no active bypass structure and manually switchable controlled objects. By redesigning the preset values in the control panel and the control logic in the electrical control system, the controlled objects can be manually switched and the variable flow regulating device and one-way valve in the active bypass are optimized, thus realizing the design of a DC inverter helium compressor with no active bypass structure.
[0006] Technical solution: The present invention provides a DC inverter helium compressor without active working bypass structure, characterized in that: it includes a DC inverter compressor, a control panel and an electrical control system. After the control mode is selected on the control panel, the electrical control system receives the input command from the control panel and combines it with the feedback signal from the high-voltage sensor to control the speed of the three-phase DC inverter synchronous motor.
[0007] The control panel is equipped with a touch screen, which displays real-time data recorded by various sensors and a parameter input interface. It allows users to select and control the high and low pressure difference of the compressor and the motor speed, and input control commands to the electronic control system.
[0008] The control system of the electrical control system receives input commands from the control panel. The control system converts the input preset values and the return values of the low-voltage sensor and the high-voltage sensor into SVPWM signals and sends them to the three-phase bridge inverter. The speed of the three-phase DC frequency converter synchronous motor is controlled according to the inverter signals.
[0009] In the low-pressure intake pipeline of the DC inverter helium compressor, the helium discharged from the cold head passes sequentially through the low-pressure return port, safety valve, low-pressure sensor, and buffer tank before entering the DC inverter compressor.
[0010] In the high-pressure exhaust pipeline of the DC inverter helium compressor, helium gas passes sequentially from the DC inverter compressor outlet through the third temperature sensor, plate heat exchanger, fourth temperature sensor, oil separator, and adsorber before entering the cold head through the high-pressure exhaust port.
[0011] The gas duct between the oil separator and the adsorber is equipped with a safety valve. The gas duct is connected to the air inlet pipe. A passive bypass solenoid valve is provided between the gas duct and the air inlet pipe. The gas duct is connected to the air inlet pipe upstream of the low-pressure sensor.
[0012] The DC inverter helium compressor is equipped with an independent lubrication oil circuit and water circuit. The oil separator drain port passes through the second filter and the second throttling orifice in sequence before connecting to the intake pipe downstream of the buffer tank. The DC inverter compressor drain port passes through the plate heat exchanger, the first filter, and the first throttling orifice in sequence before returning to the oil inlet of the DC inverter compressor. Cooling water enters the compressor system from the water circuit inlet, passes through the first temperature sensor, the heat exchanger, and the second temperature sensor in sequence, and is discharged from the compressor system from the water circuit outlet.
[0013] The bypass circuit is equipped with only a solenoid valve, and does not include a check valve or a variable flow regulating device for active bypass function.
[0014] The control system has a preset maximum pressure value, which is between the safety valve pressure and the working pressure. The operating frequency is manually set. When the pressure collected by the high-pressure sensor is greater than the preset pressure, the duty cycle of the SVPWM signal is reduced and the speed of the three-phase DC inverter synchronous motor is reduced. When the speed drops to the lowest value of the operating frequency range, 20Hz, the compressor stops running. If the pressure collected by the high-pressure sensor is lower than the preset pressure, the frequency is increased or decreased to make the actual operating frequency meet the preset value. After the preset value is reached, the system maintains a stable operating state.
[0015] The control system has a preset maximum pressure value, which is between the safety valve pressure and the working pressure. The working pressure difference is manually set. When the pressure collected by the high-pressure sensor is greater than the preset pressure, the duty cycle of the SVPWM signal is reduced and the speed of the three-phase DC inverter synchronous motor is reduced. When the speed drops to the lowest value of the working frequency range, 20Hz, the compressor stops running. If the pressure collected by the high-pressure sensor is lower than the preset pressure, the frequency is increased or decreased to make the actual operating pressure difference meet the preset value. After the preset value is reached, the system maintains a stable working state.
[0016] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention replaces the traditional AC inverter pressure transformer with a DC inverter pressure transformer, reducing energy loss and power consumption. Compared to AC inverters with the same frequency range, the size and weight are reduced, meeting the requirements for miniaturization and lightweight design. Through control program settings in the electrical control system, this invention eliminates the one-way valve and variable flow regulating device in the traditional inverter compressor's active bypass, effectively reducing costs and simplifying the mechanical structure. This invention optimizes the control panel, allowing selection of differential pressure or frequency as the controlled object, meeting the inverter compressor needs of different user groups. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of the present invention;
[0018] Figure 2 This is a flowchart illustrating the frequency control strategy of the present invention.
[0019] Figure 3 This is a schematic diagram of the differential pressure control strategy of the present invention;
[0020] Figure 4 This is a schematic diagram of the control logic of the present invention;
[0021] In the diagram, 1 is the DC inverter pressure transformer; 2 is the control panel; 3 is the electrical control system; 4 is the first throttling orifice; 5 is the first filter; 6 is the plate heat exchanger; 7 is the water outlet; 8 is the water inlet; 9 is the second throttling orifice; 10 is the second filter; 11 is the buffer tank; 12 is the solenoid valve; 13 is the oil separator; 14 is the adsorber; 15 is the low-pressure return port; 16 is the high-pressure inlet; 17 is the control system; 18 is the three-phase bridge inverter; 19 is the three-phase DC inverter synchronous motor; 20 is the cold head; 21 is the high-pressure sensor; 22 is the low-pressure sensor; 23 is the safety valve; 24 is the first temperature sensor; 25 is the second temperature sensor; 26 is the third temperature sensor; and 27 is the fourth temperature sensor. Detailed Implementation
[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0023] This invention discloses a DC inverter helium compressor without an active bypass structure, comprising a DC inverter compressor 1, a control panel 2, and an electronic control system 3. The DC inverter compressor 1 incorporates a permanent magnet synchronous brushless DC motor, which has a wide frequency adjustment range, meeting the requirements of 20-100Hz, and offers advantages in efficiency and lightweight compared to a three-phase DC inverter synchronous motor 19. The control panel 2 features two control modes: manual frequency adjustment and differential pressure adjustment. Control modes can be switched manually by inputting parameters. After reading the input commands from the control panel 2, the electronic control system 3 compares the current pressure with the set pressure. If the pressure at the current frequency is higher than the target value, the frequency is reduced; if the operating frequency is lower than the compressor's minimum frequency, the compressor stops. Compared to traditional AC inverter compressors, this invention optimizes the variable flow adjustment device and check valve in the active bypass, retaining only the solenoid valve for pressure balancing in the passive bypass. Furthermore, the system supports manual selection of either differential pressure or frequency adjustment as the compressor control mode, enabling it to handle various operating scenarios such as cryogenic pumps and pulse tube refrigerators.
[0024] like Figure 1 The present invention provides a DC inverter helium compressor without active bypass, comprising a DC inverter compressor 1, a control panel 2, and an electrical control system 3.
[0025] The entire gas pipeline of the DC inverter helium compressor without active bypass is as follows: low-pressure helium discharged from the cold head 20 enters the system through the low-pressure return port 15 in the inlet pipeline; one end of the low-pressure sensor 22 is connected to the low-pressure return port 15; the other end of the low-pressure sensor 22 is connected to one end of the buffer tank 11; the other end of the buffer tank 11 is connected to the DC inverter compressor 1; after being compressed in the DC inverter compressor 1, the helium is discharged from the other end, and the other end of the DC inverter compressor 1 is connected to one end of the third temperature sensor 26 in the exhaust pipeline; the other end of the third temperature sensor 26 is connected to the plate heat exchanger 6. One end is connected; the other end of the plate heat exchanger 6 is sequentially connected to the fourth temperature sensor 27 and one end of the oil separator 13; a safety valve 23 and a high-pressure sensor 21 are provided on the gas guide pipe between the oil separator 13 and the adsorber 14. The gas guide pipe is connected to the inlet pipe via a passive bypass. A solenoid valve 12 is provided on the passive bypass to balance the pressure inside the compressor when the machine stops. The gas guide pipe is connected to the inlet pipe upstream of the low-pressure sensor 22; the other end of the adsorber 14 is connected to one end of the high-pressure inlet 16. The other end of the high-pressure inlet 16 is connected to the inlet of the cold head 20 and enters the cold head 20.
[0026] After being separated by the oil separator 13, the lubricating oil is connected in series with the second filter 10 and the second throttling orifice 9 and then flows into the downstream of the low-pressure sensor 22 in the intake pipeline; and is connected to one end of the intake port of the DC inverter pressure pack 1; after being pressurized and separated, the lubricating oil is collected at the bottom of the DC inverter pressure pack 1 and flows through the oil drain port to the plate heat exchanger 6, the first filter 5, and the first throttling orifice 4 in sequence before returning to the DC inverter pressure pack 1.
[0027] After entering the compressor system through the water inlet 8, the cooling water passes through the first temperature sensor 24, the plate heat exchanger 6, and the second temperature sensor 25 in sequence before being discharged from the compressor system through the water outlet 7.
[0028] Control panel 2 features a touchscreen displaying real-time data and parameter input from the first to fourth temperature sensors, as well as high-pressure sensor 21 and low-pressure sensor 22. It allows selection of controls for the compressor's high and low pressure differential and motor speed, and inputs control commands to the electrical control system 3. In electrical control system 3, control system 17 receives input commands from control panel 2. Based on preset values and the return values from low-pressure sensor 22 and high-pressure sensor 21, control system 17 converts the control signals into PWM signals and sends them to the three-phase bridge inverter 18. The inverter signals control the speed of the three-phase DC inverter synchronous motor 19. The temperature and pressure sensors are pre-set to a default maximum value at the factory. During operation, any sensor reading exceeding the preset value will trigger an alarm signal and shut down the machine.
[0029] Figure 2This is a flowchart illustrating the frequency control strategy of the present invention. After the compressor starts, the required differential pressure value is manually input on the control panel 2. The compressor then checks whether the current operating differential pressure is greater than the set differential pressure. If it is greater, the compressor operating frequency decreases; otherwise, the operating frequency increases. Next, it checks whether the recorded value of the high-pressure sensor 21 is greater than the set maximum pressure. If it is less than the set value, it checks whether the current differential pressure has reached the set value. If the differential pressure setting is met, the frequency is maintained at a stable operating frequency, and the check of the high-pressure sensor 21 is repeated after a period of time. If the motor frequency has not reached the set value, the process returns to checking whether the manually input frequency is greater than the set frequency. If the high-pressure is greater than the set value, it checks whether the motor operating frequency is 20Hz. If the operating frequency is 20Hz, the system is considered abnormal and the compressor is immediately stopped. If the motor operating frequency is not 20Hz, the compressor operating frequency is reduced. Then, it checks whether the high-pressure is higher than the set value. If it is higher than the set value, the process returns to the previous step to further reduce the compressor operating frequency. If the pressure is not higher than the set value, the system continues to check if the high-pressure pressure is lower than the set value. If it is not lower than the set value, the set value and the measured value are consistent, and the compressor continues to operate stably with the frequency unchanged. After a certain interval, the system returns to check if the high-pressure pressure is higher or lower after the compressor frequency has increased or decreased. If the high-pressure pressure is lower than the set value, the system returns to check if the current frequency after manually inputting the frequency is higher than the set frequency.
[0030] Figure 3This is a flowchart illustrating the differential pressure control strategy of the present invention. After the compressor starts, the required frequency value is manually input on the control panel 2. The compressor then checks whether the current operating frequency is greater than the set frequency. If it is, the compressor operating frequency decreases; otherwise, it increases. Next, it checks whether the recorded value of the high-pressure sensor 21 is greater than the set maximum pressure. If it is less than the set value, it checks whether the motor frequency has reached the set value. If the motor frequency meets the set value, it maintains stable operation at that frequency and checks the high-pressure sensor 21 again after a period of time. If the motor frequency has not reached the set value, it returns to checking whether the manually input frequency is greater than the set frequency. If the high-pressure is greater than the set value, it checks whether the motor operating frequency is 20Hz. If the operating frequency is 20Hz, it is determined that there is an abnormality in the system, and the compressor is immediately stopped. If the motor operating frequency is not 20Hz, the compressor operating frequency is reduced. Then, it checks whether the high-pressure is higher than the set value. If it is higher than the set value, it returns to the previous step to continue reducing the compressor operating frequency. If the pressure is not higher than the set value, the system continues to check if the high-pressure pressure is lower than the set value. If it is not lower than the set value, the set value and the measured value are consistent, and the compressor continues to operate stably with the frequency unchanged. After a certain interval, the system returns to check if the high-pressure pressure is higher or lower after the compressor frequency has increased or decreased. If the high-pressure pressure is lower than the set value, the system returns to check if the current frequency after manually inputting the frequency is higher than the set frequency.
[0031] Figure 4 The diagram illustrates the control logic of this invention. The motor frequency and high / low pressure difference are set in the control panel. Based on the error between the pressure reading of the high-pressure sensor and the desired pressure, the PID controller and speed limiter convert the signal and output it in the form of a SVPWM duty cycle signal. The inverter converts the signal and ultimately controls the speed of the DC inverter motor.
[0032] The present invention has been described above with reference to the embodiments. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments, and various design changes and modifications are possible, and such modifications are also within the scope of the present invention.
Claims
1. A DC inverter helium compressor without an active bypass structure, characterized in that: The system includes a DC inverter voltage transformer (1), a control panel (2), and an electrical control system (3). After selecting the control mode on the control panel (2), the electrical control system (3) receives the input command from the control panel (2) and combines it with the feedback signal from the high voltage sensor (21) to control the speed of the three-phase DC inverter synchronous motor (19).
2. The DC inverter helium compressor without active bypass structure according to claim 1, characterized in that: The control panel (2) is equipped with a touch screen, which has real-time data recorded by various sensors and a parameter input interface. It can select to control the high and low pressure difference of the compressor and the motor speed, and input the control command to the electronic control system (3).
3. The DC inverter helium compressor without an active bypass structure according to claim 1, characterized in that: The control system (17) of the electrical control system (3) receives input instructions from the control panel (2). The control system (17) converts the input preset value and the return values of the low-voltage sensor (22) and the high-voltage sensor (21) into an SVPWM signal and sends it to the three-phase bridge inverter (18). The speed of the three-phase DC frequency conversion synchronous motor (19) is controlled according to the inverter signal.
4. The DC inverter helium compressor without active bypass structure according to claim 1, characterized in that: In the low-pressure inlet pipeline of the DC inverter helium compressor, the helium discharged from the cold head (20) passes through the low-pressure return port (15), safety valve (23), low-pressure sensor (22), and buffer tank (11) in sequence before entering the DC inverter compressor (1).
5. The DC inverter helium compressor without an active bypass structure according to claim 1, characterized in that: In the high-pressure exhaust pipeline of the DC inverter helium compressor, helium gas passes through the third temperature sensor (26), plate heat exchanger (6), fourth temperature sensor (27), oil separator (13), and adsorber (14) in sequence from the outlet of the DC inverter compressor (1) and then enters the cold head (20) through the high-pressure exhaust port (16).
6. The DC inverter helium compressor without an active bypass structure according to claim 5, characterized in that: A safety valve (23) is provided on the air guide pipe between the oil separator (13) and the adsorber (14). The air guide pipe is connected to the air inlet pipe. A passive bypass solenoid valve (12) is provided between the air guide pipe and the air inlet pipe. The air guide pipe is connected to the air inlet pipe upstream of the low pressure sensor (22).
7. The DC inverter helium compressor without an active bypass structure according to claim 6, characterized in that: The DC inverter helium compressor is equipped with an independent lubricating oil circuit and water circuit. The oil separator (13) discharge port passes through the second filter (10) and the second throttle hole (9) in sequence and then enters the intake pipe downstream of the buffer tank (11). The DC inverter compressor (1) discharge port passes through the plate heat exchanger (6), the first filter (5), and the first throttle hole (4) in sequence and then returns to the oil inlet of the DC inverter compressor (1). After the cooling water enters the compressor system from the water inlet (8), it passes through the first temperature sensor (24), the heat exchanger (6), and the second temperature sensor (25) in sequence and then exits the compressor system from the water outlet (7).
8. The DC inverter helium compressor without active bypass structure according to claim 6, characterized in that: The bypass circuit is equipped with only a solenoid valve (12), and does not include a check valve or a variable flow regulating device to perform active bypass function.
9. The DC inverter helium compressor without an active bypass structure according to claim 1, characterized in that: The control system (17) has a preset maximum pressure value, which is between the pressure of the safety valve (23) and the working pressure. The working frequency is manually set. When the pressure collected by the high pressure sensor (21) is greater than the preset pressure, the duty cycle of the SVPWM signal will be reduced and the speed of the three-phase DC inverter synchronous motor (19) will be reduced. When the speed is reduced to the lowest value of the working frequency range, 20Hz, the compressor will stop running. If the pressure collected by the high pressure sensor (21) is lower than the preset pressure, the actual operating frequency will be increased or decreased to meet the preset value. After the preset value is reached, the system will maintain a stable working state.
10. The DC inverter helium compressor without active bypass structure according to claim 1, characterized in that: The control system (17) has a preset maximum pressure value, which is between the pressure of the safety valve (23) and the working pressure. The working pressure difference is manually set. When the pressure collected by the high pressure sensor (21) is greater than the preset pressure, the duty cycle of the SVPWM signal will be reduced and the speed of the three-phase DC inverter synchronous motor (19) will be reduced. When the speed is reduced to the lowest value of the working frequency range, 20Hz, the compressor will stop running. If the pressure collected by the high pressure sensor (21) is lower than the preset pressure, the actual operating pressure difference will be made to meet the preset value by increasing or decreasing the frequency. After the preset value is reached, the system will maintain a stable working state.