Laser refrigeration system based on energy hierarchical control

Abstract

The invention belongs to the technical field of water chiller refrigeration control, and particularly relates to a laser refrigeration system based on energy hierarchical control. Comprising a first fluorine circulation assembly, a second fluorine circulation assembly, a water circulation assembly and a control assembly. The fluorine circulation assembly comprises a compressor, a condenser and a throttle valve; the water circulation assembly comprises a heat exchanger, a low-temperature water tank and a water pump. The control assembly comprises a controller, a temperature sensor, a heating element and a compressor control switch. The energy consumption in the starting and running process of the refrigerating system can be effectively reduced, the influence of the laser on the refrigerating circulating system is reduced, the production efficiency is improved, meanwhile, the refrigerating output stability is improved, the laser light source quality and stability are improved, and the service life of the laser is prolonged. And the overall use and maintenance cost of the laser system is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chiller refrigeration control, and in particular relates to a laser refrigeration system based on energy graded control. Background Art

[0002] A chiller is a cooling water device that can provide constant temperature, constant flow and constant pressure. The compressor is the core power unit in the chiller circulation system. Since the compressor needs to operate under light load, it generally needs to wait for the system pressure to balance before it can be started again. During this period, the system refrigeration is in a low controllable state. In order to achieve precision control, the current chiller system adds a bypass solenoid valve to the cooling system to control the direction of the refrigerant, so that the temperature can be controlled without stopping the compressor. However, this method causes the compressor to run for a long time, consumes a lot of energy, and has a lot of mechanical wear. This results in a reduction in the life of the compressor and makes it difficult to ensure operational stability. Summary of the invention

[0003] The purpose of the present invention is to provide a laser refrigeration system based on energy graded control that can better control the operation process of the compressor, ensure that the compressor in the system can achieve stable endurance, and can increase the cooling capacity of the system, reduce the impact of the laser head heat source on the refrigeration system, achieve temperature control faster and better, and improve the output stability of the refrigeration system.

[0004] To achieve the above purpose, the present invention adopts the following technical solution.

[0005] A laser refrigeration system based on energy graded control, comprising a No. 1 fluorine circulation component, a No. 2 fluorine circulation component, a water circulation component, and a control component;

[0006] The No. 1 fluorine cycle assembly includes a No. 1 compressor 1, a No. 1 condenser 3, and a No. 1 throttle valve 5;

[0007] The No. 2 fluorine cycle assembly includes a No. 2 compressor 2, a No. 2 condenser 4, and a No. 2 throttle valve 6;

[0008] The water circulation assembly includes a heat exchanger 7, a low-temperature water tank 9, and a water pump 10;

[0009] The No. 1 compressor 1, the No. 1 condenser 3, and the No. 1 throttle valve 5 are sequentially connected through the fluorine circulation pipe and connected to the cold side of the heat exchanger 7 to form a primary refrigeration circulation loop; the No. 2 compressor 2, the No. 2 condenser 4, and the No. 2 throttle valve 6 are sequentially connected through the fluorine circulation pipe and connected to the cold side of the heat exchanger 7 to form a secondary refrigeration circulation loop; the heat exchanger 7, the low-temperature water tank 9, and the water pump 10 are sequentially connected through the water pipe and connected to the refrigeration side of the laser to form a refrigeration circulation loop;

[0010] The control assembly includes: a controller, a temperature sensor, a heating element 2, and a compressor control switch; the temperature sensor and the heating element 8 are arranged in a low-temperature water tank 9, and the compressor control switch is respectively arranged on the No. 1 compressor 1 and the No. 2 compressor 2;

[0011] The controller is used to perform the following steps:

[0012] Step 1, set parameters, set the preset target temperature T0∈[25,35], the primary control variable ΔT1∈[0.2,1.5], and the secondary control variable ΔT2∈[0.2,1.5];

[0013] Step 2, the first round of control, continuously detect the temperature data in the low-temperature water tank 9, and turn on the No. 1 compressor when it is detected that the water temperature rises to T0+ΔT1°C. If the water temperature continues to rise to T0+ΔT1+ΔT2°C, turn on the No. 2 compressor until the water temperature drops to T0-ΔT1°C and then turn off the No. 2 compressor. When the water temperature drops to T0-ΔT1-ΔT2°C, turn off the No. 1 compressor, and end the first round of control;

[0014] Step 3, the second round of control, after the first round of control, continue to detect the temperature data in the low temperature water tank 9, if it is detected

[0015] When the water temperature rises to T0+ΔT1℃, start the No.2 compressor. If the water temperature continues to rise to T0+ΔT1+ΔT2℃, ​​start the No.1 compressor until the water temperature drops to T0-ΔT1℃, then turn off the No.1 compressor. When the water temperature drops to T0-ΔT1-ΔT2℃, ​​turn off the No.2 compressor, and end the second round of control.

[0016] Step 4: loop the control process of steps 2 and 3 above. If the water temperature is detected to be lower than T0-ΔT1-ΔT2°C, turn on the heating element to maintain the water temperature above T0.

[0017] A further improvement or preferred implementation of the aforementioned laser refrigeration system based on energy graded control, the controller is also used to: set a downtime t0, each time each compressor is shut down, it will not run again until a time interval of t0 has passed, under this premise, the compressor operation is controlled according to the order of step 2 and step 3.

[0018] A further improvement or preferred implementation of the aforementioned laser refrigeration system based on energy graded control is that T0 = 26°C; ΔT1 = 0.3°C, ΔT2 = 0.7°C.

[0019] A further improvement or preferred embodiment of the aforementioned laser refrigeration system based on energy graded control, the controller is also used to obtain or estimate the orthogonal axis electrical synchronization parameters of the compressor motor based on a pulsed high-frequency voltage injection method, determine the error angle, and optimize the compressor motor operating parameters based on an adaptive angle error compensator.

[0020] A further improvement or preferred embodiment of the aforementioned laser refrigeration system based on energy graded control, wherein the pulsed high-frequency voltage injection method is used to obtain or estimate the orthogonal axis electrical synchronization parameters of the compressor motor and determine the error angle. Specifically, the pulsed high-frequency voltage injection method is used to obtain or estimate the orthogonal axis electrical synchronization parameters of the compressor motor and determine the error angle.

[0021] Based on the basic parameters of the compressor motor and the monitoring sensors, the orthogonal axis electrical synchronous rotating coordinate system dq of the compressor motor is obtained or estimated, and the compressor motor torque output equation is established:

[0022]

[0023] ω r is the motor speed, i d is the quadrature axis current, i q is the direct axis current, R s is the rotor resistance, L d is the compressor motor cross-axis inductive reactance, L q is the direct-axis inductive reactance of the compressor motor, u d is the compressor motor quadrature axis voltage, u q is the compressor motor direct-axis voltage;

[0024] Inject a high-frequency sinusoidal voltage into the direct axis, and through the salient pole effect, obtain the high-frequency response current in the steady state:

[0025]

[0026] where z dh represents the direct axis impedance, z qh represents the quadrature-axis impedance;

[0027] Transform the induced current to the observation coordinate system and obtain the high-frequency induced current expression:

[0028]

[0029] Multiply both sides of the simplified quadrature-axis high-frequency current by the demodulated signal sinω h t, and then filter out the frequency of 2ω through a high-pass filter h The high-frequency signal of the error angle Δθ is obtained. r The signal can be expressed as:

[0030]

[0031] in Represents high-frequency sinusoidal voltage U hm =u hm cos(ω h t) Input the lower error angle coefficient.

[0032] Its beneficial effects are:

[0033] The laser refrigeration system based on energy graded control of the present application can effectively reduce energy consumption during the startup and operation of the refrigeration system, reduce the impact of the laser on the refrigeration cycle system, improve production efficiency, and at the same time improve the stability of the refrigeration output, improve the quality and stability of the laser light source, extend the service life of the laser, and thus reduce the overall use and maintenance cost of the laser system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the laser refrigeration system based on energy graded control;

[0035] Figure 2 It is a schematic diagram of the temperature control mode of the low-temperature water tank. DETAILED DESCRIPTION

[0036] The present invention is described in detail below in conjunction with specific embodiments.

[0037] The laser refrigeration system based on energy graded control of the present invention is mainly used as a cooling capacity control system in a refrigeration cycle system of equipment such as lasers, and is used to reduce the impact of the laser refrigerator on the refrigeration system and solve the problem that the traditional bypass control method causes the compressor to continuously run at high pressure, resulting in the laser being unable to work continuously.

[0038] The main components of the laser refrigeration system based on energy graded control include No. 1 fluorine cycle component, No. 2 fluorine cycle component, water cycle component, and control component;

[0039] The No. 1 fluorine cycle assembly includes a No. 1 compressor 1, a No. 1 condenser 3, and a No. 1 throttle valve 5; the No. 2 fluorine cycle assembly includes a No. 2 compressor 2, a No. 2 condenser 4, and a No. 2 throttle valve 6;

[0040] The water circulation components include a heat exchanger 7, a low-temperature water tank 9, and a water pump 10;

[0041] The No. 1 compressor 1, the No. 1 condenser 3, and the No. 1 throttle valve 5 are sequentially connected through the fluorine circulation pipe and connected to the cold side of the heat exchanger 7 to form a primary refrigeration circulation loop; the No. 2 compressor 2, the No. 2 condenser 4, and the No. 2 throttle valve 6 are sequentially connected through the fluorine circulation pipe and connected to the cold side of the heat exchanger 7 to form a secondary refrigeration circulation loop; the heat exchanger 7, the low-temperature water tank 9, and the water pump 10 are sequentially connected through the water pipe and connected to the refrigeration side of the laser to form a refrigeration circulation loop;

[0042] The control assembly includes: a controller, a temperature sensor, a heating element 2, and a compressor control switch;

[0043] The temperature sensor and the heating element 8 provided in the low temperature water tank 9, and the compressor control switches provided on the compressor No. 1 and the compressor No. 2, respectively;

[0044] The controller is used to perform the following steps:

[0045] Step 1, set parameters, set the preset target temperature T0∈[25,35], the primary control variable ΔT1∈[0.2,1.5], and the secondary control variable ΔT2∈[0.2,1.5];

[0046] Based on actual operating experience and the use conditions and cooling requirements of conventional lasers, in this embodiment, T0 = 26°C; ΔT1 = 0.3°C, ΔT2 = 0.7°C;

[0047] Step 2, the first round of control, continuously detect the temperature data in the low-temperature water tank 9, and turn on the No. 1 compressor when it is detected that the water temperature rises to T0+ΔT1°C. If the water temperature continues to rise to T0+ΔT1+ΔT2°C, turn on the No. 2 compressor until the water temperature drops to T0-ΔT1°C and then turn off the No. 2 compressor. When the water temperature drops to T0-ΔT1-ΔT2°C, turn off the No. 1 compressor, and end the first round of control;

[0048] Step 3, the second round of control, after the first round of control, continue to detect the temperature data in the low temperature water tank 9, if it is detected

[0049] When the water temperature rises to T0+ΔT1℃, start the No.2 compressor. If the water temperature continues to rise to T0+ΔT1+ΔT2℃, ​​start the No.1 compressor until the water temperature drops to T0-ΔT1℃, then turn off the No.1 compressor. When the water temperature drops to T0-ΔT1-ΔT2℃, ​​turn off the No.2 compressor, and end the second round of control.

[0050] Step 4, loop the control process of the above steps 2 and 3, if the water temperature is detected to be lower than T0-ΔT1-ΔT2°C, turn on the heating element to maintain the water temperature above T0;

[0051] In the laser refrigeration cycle, all the low-temperature water required for cooling the heat source is in the low-temperature water tank 9. The water pump 10 draws the low-temperature water from the low-temperature water tank 9, and the water flows from the water outlet of the water pump 10 to the heat source of the laser 11 to cool the laser 11. The cooling water that has completed the refrigeration returns to the heat exchanger 7 to complete the heat exchange with the refrigeration system. After the exchange is completed, the low-temperature cooling water flows into the low-temperature water tank 9 again.

[0052] In order to better protect the motor and achieve precise temperature control, the controller also controls the operation of the two compressor motors to reduce motor start-up delay and startup power consumption, including:

[0053] Steps for obtaining the compressor motor speed and angle during the startup process: Based on the pulse high-frequency voltage injection method, based on the compressor motor basic parameters and monitoring sensors, obtain or estimate the orthogonal axis electrical synchronous rotating coordinate system dq of the compressor motor, and establish the compressor motor torque output equation:

[0054]

[0055] ω r is the motor speed, i d is the quadrature axis current, i q is the direct axis current, R s is the rotor resistance, L d is the compressor motor cross-axis inductive reactance, L q is the direct-axis inductive reactance of the compressor motor, u d is the compressor motor quadrature axis voltage, u q is the compressor motor direct-axis voltage;

[0056] A high-frequency sinusoidal voltage is injected into the direct axis to demodulate the error angle Δθ from the quadrature axis current through the saliency effect. r , and then track the rotor angle through a phase-locked loop; specifically:

[0057] Assume that the injected high frequency sinusoidal voltage U hm =u hm cos(ω h t), the voltage acting on the real coordinate system can be expressed as

[0058] where u hm represents the injected high-frequency sinusoidal voltage amplitude, u dn represents the direct axis voltage in the real coordinate system, u qh It represents the quadrature axis voltage of the real coordinate system;

[0059] If the injected high-frequency voltage has an extreme action period, the reverse electromotive force can be ignored, and the high-frequency response current in the steady state can be expressed as:

[0060]

[0061] where z dh represents the direct axis impedance, z qh represents the quadrature-axis impedance;

[0062] Transforming the induced current to the observation coordinate system, the expression of high-frequency induced current is as follows:

[0063]

[0064] It refers to the direct-axis high-frequency induced current, It refers to the cross-axis high-frequency induced current;

[0065] At high frequencies, the direct axis impedance z dh and the quadrature axis impedance z qh Only the imaginary part needs to be considered, combined with the impedance formula z = R + jwl; then the quadrature axis high frequency current can be simplified to

[0066] Multiply both sides of the simplified quadrature-axis high-frequency current by the demodulated signal sinω h t, and then filter out the frequency of 2ω through a high-pass filter h The high-frequency signal of the error angle Δθ is obtained. r The signal can be expressed as:

[0067]

[0068] in Represents high-frequency sinusoidal voltage U hm =u hm cos(ω h t) Input the lower error angle coefficient.

[0069] Based on the above methods and principles, the system composed of the dual-circulation refrigeration components of the present application can obtain a shorter startup time and a more precise startup control effect. By using two compressors in coordination, the static and dynamic switching of the refrigeration system can be quickly completed, effectively reducing the startup time of the refrigeration system. At the same time, it reduces the difficulty of coordinated control of the compressors, and obtains a more precise and efficient refrigeration effect.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A laser refrigeration system based on energy graded control, characterized in that: It includes No. 1 fluorine circulation assembly, No. 2 fluorine circulation assembly, water circulation assembly and control assembly; The No. 1 fluorine cycle assembly comprises a No. 1 compressor (1), a No. 1 condenser (3), and a No. 1 throttle valve (5); The second fluorine cycle assembly includes a second compressor (2), a second condenser (4), and a second throttle valve (6); The water circulation component comprises a heat exchanger (7), a low-temperature water tank (9), and a water pump (10); The first compressor (1), the first condenser (3), and the first throttle valve (5) are sequentially connected through a fluorine circulation pipe and connected to the cold side of the heat exchanger (7) to form a primary refrigeration circulation loop; the second compressor (2), the second condenser (4), and the second throttle valve (6) are sequentially connected through a fluorine circulation pipe and connected to the cold side of the heat exchanger (7) to form a secondary refrigeration circulation loop; the heat exchanger (7), the low-temperature water tank (9), and the water pump (10) are sequentially connected through a water pipe and connected to the cold side of the laser to form a refrigeration circulation loop; The control assembly comprises: a controller, a temperature sensor, a heating element (2), and a compressor control switch; the temperature sensor and the heating element (8) are arranged in a low-temperature water tank (9), and the compressor control switches are respectively arranged on the first compressor (1) and the second compressor (2); The controller is used to perform the following steps: Step 1, set parameters, set the preset target temperature T0∈[25,35], the primary control variable ΔT1∈[0.2,1.5], and the secondary control variable ΔT2∈[0.2,1.5]; Step 2, the first round of control, continuously detecting the temperature data in the low-temperature water tank (9), when detecting that the water temperature rises to T0+ΔT1°C, start the No. 1 compressor, if the water temperature continues to rise to T0+ΔT1+ΔT2°C, start the No. 2 compressor until the water temperature drops to T0-ΔT1°C, then turn off the No. 2 compressor, when the water temperature drops to T0-ΔT1-ΔT2°C, turn off the No. 1 compressor, and end the first round of control; Step 3, second round of control, after the first round of control, continuously detect the temperature data in the low temperature water tank (9), if detected When the water temperature rises to T0+ΔT1℃, start the No.2 compressor. If the water temperature continues to rise to T0+ΔT1+ΔT2℃, ​​start the No.1 compressor until the water temperature drops to T0-ΔT1℃, then turn off the No.1 compressor. When the water temperature drops to T0-ΔT1-ΔT2℃, ​​turn off the No.2 compressor, and end the second round of control. Step 4: loop the control process of steps 2 and 3 above. If the water temperature is detected to be lower than T0-ΔT1-ΔT2°C, turn on the heating element to maintain the water temperature above T0.

2. The laser refrigeration system based on energy graded control according to claim 1, characterized in that: The controller is also used to set a shutdown time t0. Each time the compressor is shut down, it needs to wait for a time t0 before running again. Under this premise, the operation of the compressor is controlled according to the sequence of step 2 and step 3.

3. The laser refrigeration system based on energy graded control according to claim 1, characterized in that: The T0=26°C; ΔT1=0.3°C, ΔT2=0.7°C.

4. The laser refrigeration system based on energy graded control according to claim 1, characterized in that: The controller is also used to obtain or estimate the orthogonal axis electrical synchronization parameters of the compressor motor based on a pulse high-frequency voltage injection method, determine the error angle, and optimize the compressor motor operating parameters based on an adaptive angle error compensator.

5. The laser refrigeration system based on energy graded control according to claim 4, characterized in that: The method of obtaining or estimating the orthogonal axis electrical synchronization parameters of the compressor motor based on the pulse high frequency voltage injection method and determining the error angle specifically refers to: Based on the basic parameters of the compressor motor and the monitoring sensors, the orthogonal axis electrical synchronous rotating coordinate system dq of the compressor motor is obtained or estimated, and the compressor motor torque output equation is established: ω r is the motor speed, i d is the quadrature axis current, i q is the direct axis current, R s is the rotor resistance, L d is the compressor motor cross-axis inductive reactance, L q is the direct-axis inductive reactance of the compressor motor, u d is the compressor motor quadrature axis voltage, u q is the compressor motor direct-axis voltage; Inject a high-frequency sinusoidal voltage into the direct axis, and through the salient pole effect, obtain the high-frequency response current in the steady state: where z dh represents the direct-axis impedance, z qh represents the quadrature-axis impedance; Transform the induced current to the observation coordinate system and obtain the high-frequency induced current expression: Multiply both sides of the simplified quadrature-axis high-frequency current by the demodulated signal sinω h t, and then filter out the frequency of 2ω through a high-pass filter h The high-frequency signal of the error angle Δθ is obtained. r The signal can be expressed as: in Represents high-frequency sinusoidal voltage U hm =u hm cos(ω h t) Input the lower error angle coefficient.

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