Room temperature magnetic heat pump control system and control method

Abstract

The invention discloses a room temperature magnetic heat pump control system and a control method, which are used for controlling the regenerative cycle operation process of a room temperature magnetic heat pump and comprise a power supply module, a sensor module, a single chip microcomputer, an actuator module and a serial port screen, the sensor module is used for collecting temperature, pressure, flow, liquid level, magnetic field position and motor operation state signals and transmitting the signals to the single-chip microcomputer. The serial port screen is connected with the single-chip microcomputer, displays and stores the signal data in real time, and sends a control signal to the single-chip microcomputer; the single-chip microcomputer receives signals of the sensor module and the serial port screen and then sends control signals to the actuator module, and closed-loop control over the room-temperature magnetic heat pump system is achieved. The single-chip microcomputer serves as a core controller to achieve automatic control and key parameter collection of the room temperature magnetic heat pump system, and it is ensured that the actual process is close to theoretical regenerative cycle through time sequence matching and parameter feedback; the problems that an existing room-temperature magnetic heat pump system is low in automation degree, low in magnetic field positioning precision, unbalanced in cold and hot flow and poor in controller following performance are solved.

Description

Technical Field

[0001] The invention relates to the technical field of room temperature magnetic heat pump and automation control, in particular to a room temperature magnetic heat pump control system and a control method. Background Art

[0002] Room temperature magnetic heat pump uses magnetocaloric material (MCM) as refrigerant to replace traditional hydrofluorocarbon refrigerant. It uses its magnetocaloric effect (MCE) to replace the process of compressor compressing steam and expansion valve expanding fluid in steam compression technology with magnetization and demagnetization process. The theoretical cycle efficiency can reach 60% of the Carnot cycle. Since MCM is solid, there is no risk of escape and leakage, no ozone depletion potential (ODP), and the global warming potential (GWP) is usually very small, which has great environmental protection benefits and broad application development prospects.

[0003] In recent years, room temperature magnetic heat pump technology has developed rapidly, and a large number of prototypes have been launched. Due to the limited magnetic induction intensity of the permanent magnetic field, the adiabatic temperature change of MCM is limited. The existing room temperature magnetic heat pump adopts the structure of active magnetic regenerator (AMR), which accumulates the energy generated by a single demagnetization by heat recovery, and increases the cycle temperature span of the system.

[0004] The AMR heat recovery process involves the alternation of magnet rotation and heat exchange fluid flow timing. The accurate heat recovery process depends on the precise matching of timing, which in turn depends on a fast-responding, accurate, and highly automated room-temperature magnetic heat pump coordinated control system.

[0005] For room temperature magnetic heat pump systems, non-automatic control methods are inefficient, lack control accuracy, and are difficult to achieve coordinated control. They do not have the ability to provide real-time feedback on sensor signals, quickly follow actuator signals, and correct positioning errors in a timely manner. They have poor speed regulation performance and are unable to achieve system self-balancing control and variable load control. It is difficult to obtain the optimal heating performance of the room temperature magnetic heat pump system, and it is impossible to know the maximum heating potential of the room temperature magnetic heat pump system.

[0006] In the room temperature magnetic heat pump system, the Halbach permanent magnet used has very high requirements for position control accuracy. The position control accuracy directly affects whether the magnetization start position / demagnetization end position is a low magnetic field, and whether the demagnetization start position / magnetization end position is a high magnetic field, thereby affecting whether the system MCM reaches the maximum magnetic entropy change under the current magnetic field strength, affecting the system temperature rise of a single demagnetization, thereby continuously affecting the energy accumulation effect of the temperature span establishment process, and ultimately affecting the system temperature span and heating output effect. Synchronous control method, system and magnetic refrigerator for magnetic refrigerator (CN202310774300.4), the invention adjusts the situation of the lowest magnetic field being out of sync by detecting the lowest magnetic field moment corresponding to each magnetic regenerator in the same magnetic regenerator module, but it requires the leading magnet to wait for the lagging magnet, which affects the overall cycle timing, and can only detect the lowest magnetic field position but not the highest magnetic field position. In summary, accurate positioning of the high / low magnetic field position of the magnet is crucial to the process and result of establishing the temperature span of the regenerative cycle.

[0007] On the other hand, in the room temperature magnetic heat pump system, due to the different lengths of the system pipelines and the different densities of cold / hot water, the pumping resistance of the first water pump and the second water pump are different, which makes the pumping flow of the first water pump and the second water pump different under the same pulse duty cycle. As a result, the water level of the water tank at one end rises slowly during operation, while the water level of the water tank at the other end drops slowly, affecting the continuous operation of the heating cycle in the room temperature magnetic heat pump heating experiment, and affecting the temperature evolution trend of the AMR axis. Therefore, achieving self-balancing of the liquid levels in the water tanks at both ends is very important for the stable operation of the room temperature magnetic heat pump heating cycle and achieving the best system heating performance. Summary of the invention

[0008] In view of the above shortcomings of the existing room temperature magnetic heat pump control technology, the purpose of the present invention is to provide an advanced room temperature magnetic heat pump control system and control method, which can realize the automatic control and human-computer interaction functions of the room temperature magnetic heat pump system, improve the response speed and accuracy, realize the operation timing matching control, PWM speed control, signal acquisition control, liquid level self-balancing control, magnetic field positioning control, variable load dynamic control of the room temperature magnetic heat pump system, real-time monitoring and feedback of the system operation status, ensure the accuracy of the magnetic field position and heat exchange flow of each heat recovery cycle, so that the room temperature magnetic heat pump system always operates in the optimal range, as close as possible to the theoretical heat recovery cycle of the room temperature magnetic heat pump, explore the maximum heating potential of the room temperature magnetic heat pump, and realize the stable heating output of the room temperature magnetic heat pump system under a large temperature range.

[0009] The present invention is achieved by at least one of the following technical solutions.

[0010] A room temperature magnetic heat pump control system, used to control the heat recovery cycle operation process of the room temperature magnetic heat pump, including a power module, a sensor module, a single chip microcomputer, an actuator module, and a serial port screen;

[0011] The sensor module is used to collect temperature, pressure, flow, liquid level, high and low magnetic field positions, and motor operating status signal data, and transmit the collected signal data to the single-chip microcomputer; the serial port screen is connected to the single-chip microcomputer to display and store the signal data collected by the sensor in real time; after the single-chip microcomputer receives the sensor module and serial port screen signals, it sends corresponding control signals to the actuator module to realize closed-loop control of the room temperature magnetic heat pump system.

[0012] The room temperature magnetic heat pump comprises the following four flow paths: a hot end heat exchange flow path, a hot flow flow path, a cold flow flow path, and a cold end heat exchange flow path;

[0013] Hot end heat exchange flow connection method: both ends of the first water pump are connected to the constant temperature water bath and the low temperature side inlet of the first heat exchanger, and the other side of the constant temperature water bath is connected to the low temperature side outlet of the first heat exchanger;

[0014] Thermal flow path connection mode: two ends of the active magnetic regenerator are connected to a first one-way valve and a second solenoid valve, the other end of the first one-way valve is connected to a second water pump, the other end of the second water pump is connected to a first water tank, the other end of the second solenoid valve is connected to a second heat exchanger, and the other end of the second heat exchanger is connected to a second water tank; the thermal flow path is used to realize the pumping of the heat exchange fluid from the first water tank through the active magnetic regenerator to the second water tank;

[0015] Cold flow path connection mode: the first solenoid valve and the second one-way valve are connected at both ends of the active magnetic regenerator, the other end of the first solenoid valve is connected to the high-temperature side inlet of the first heat exchanger, the high-temperature side outlet of the first heat exchanger is connected to the first water tank, the other end of the second one-way valve is connected to the third water pump, and the other end of the third water pump is connected to the second water tank; the cold flow path is used to realize the pumping of the heat exchange fluid from the second water tank through the active magnetic regenerator to the first water tank;

[0016] Cold end heat exchange flow connection method: The PTC heating sheet is attached to the surface of the second heat exchanger, and the hot flow fluid flows through the second heat exchanger to achieve heat exchange. The thermal compensation method is used to simulate the cold end heat load and measure the cooling capacity.

[0017] The active magnetic regenerator is located inside the Halbach magnet group, and the Halbach magnet group includes a Halbach inner magnet and a Halbach outer magnet. The Halbach inner magnet is located inside the Halbach outer magnet, and the two are in a nested double-layer ring shape. The Halbach outer magnet is fixed to the frame, and the Halbach inner magnet is connected to the driven gear, and the driven gear is connected to the driving gear through a toothed belt, and the driving gear is located on the output shaft of the servo motor. The servo motor provides power for the Halbach inner magnet through the above transmission connection, and a magnetic field with varying sizes is formed in the middle pore area between the Halbach inner magnet and the Halbach outer magnet through the relative movement of the Halbach inner magnet and the Halbach outer magnet. The active magnetic regenerator is placed in the middle pore area, and a magnetic field positioning mark is provided on the magnet block of the Halbach inner magnet, which cooperates with the first metal proximity switch sensor and the second metal proximity switch sensor to realize the positioning of the high / low magnetic field.

[0018] Preferably, the sensor module includes a temperature sensor module, a pressure sensor module, a flow sensor module, a liquid level sensor module, a metal proximity switch sensor module, a magnetic induction proximity switch sensor, and a servo encoder;

[0019] The temperature sensor module includes a plurality of temperature sensors, which are respectively used to monitor the hot end temperature of the active magnetic regenerator, the cold end temperature of the active magnetic regenerator, the temperature of the first water tank, the temperature of the second water tank, the ambient temperature, the low temperature side inlet temperature of the first heat exchanger, the low temperature side outlet temperature of the first heat exchanger, the high temperature side inlet temperature of the first heat exchanger, the high temperature side outlet temperature of the first heat exchanger, the second heat exchanger inlet temperature, and the second heat exchanger outlet temperature;

[0020] The pressure sensor module includes a plurality of pressure sensors, which are respectively used to monitor the pumping pressure of the second water pump and the third water pump and the pressure drop loss of the heat exchange fluid after flowing through the active magnetic regenerator;

[0021] The flow sensor module includes a first flow sensor, a second flow sensor, and a third flow sensor, which are respectively used to monitor the heat exchange flow of the hot flow, the cold flow, and the heat exchange flow of the heat exchange fluid on the water bath side;

[0022] The liquid level sensor module includes a first liquid level sensor and a second liquid level sensor, which are used to monitor the liquid level changes of the first water tank and the second water tank respectively;

[0023] The metal proximity switch sensor module includes a first metal proximity switch sensor for realizing high magnetic field positioning and a second metal proximity switch sensor for realizing low magnetic field positioning. Before the system is operated, the high magnetic field and low magnetic field positions of the magnetic field are calibrated by the magnetic induction proximity switch sensor. When the system is operated, the metal proximity switch sensor module can be used to provide a signal indicating that the magnetization / demagnetization position is in place during the cycle.

[0024] The magnetic induction proximity switch sensor is used to achieve initial calibration of high and low magnetic field positions;

[0025] The servo encoder is connected to the servo motor and the servo driver, and is used to convert mechanical signals into electrical signals, realize the feedback of the servo motor position and speed information to the control system, and ensure the operation accuracy of the servo motor.

[0026] Preferably, the actuator module includes a servo motor, a first water pump, a second water pump, a third water pump, a PTC heating plate, a first solenoid valve, a second solenoid valve, a servo driver, a photoelectric coupler, a water pump driver, a PTC driver, and a relay;

[0027] The servo motor is connected to the servo driver, receives the pulse control signal, completes the predetermined action, and is connected to the Halbach inner magnet through the driving gear, the toothed belt, and the driven gear to control the periodic rotation of the Halbach inner magnet. Each time the Halbach inner magnet rotates 180°, a magnetization or demagnetization process of the system is realized;

[0028] The first water pump, the second water pump and the third water pump are connected to the water pump driver, the first water pump is used to drive the heat exchange between the heat exchange fluid and the cold flow fluid on the constant temperature water bath side, and the second water pump and the third water pump are used to drive the circulation of the hot flow fluid and the cold flow fluid, respectively controlling the hot flow time / flow rate of the heat transfer fluid after demagnetization and the cold flow time / flow rate of the heat transfer fluid after magnetization;

[0029] The PTC heating sheet is connected to the PTC driver and attached to the surface of the second heat exchanger to provide a heat load to the cold end of the room temperature magnetic heat pump, thereby realizing the measurement of cooling capacity by the thermal compensation method;

[0030] The first solenoid valve and the second solenoid valve are connected to the relay to control the flow path on and off to ensure the correct timing of cold / hot flow;

[0031] The servo driver is connected with the photoelectric coupler, the servo motor, the servo encoder, and the single-chip microcomputer, and is used to receive the pulse control signal sent by the single-chip microcomputer to the photoelectric coupler and drive the servo motor, realize the primary transmission of the servo encoder feedback signal to the servo driver, and realize the secondary transmission of the servo encoder feedback signal to the single-chip microcomputer via the servo driver;

[0032] The photoelectric coupler is connected to the single chip microcomputer and the servo driver to realize drive signal amplification and photoelectric isolation protection;

[0033] The water pump driver is connected to the single-chip microcomputer and the water pump, and is used to convert the single-chip microcomputer control signal into an effective voltage at both ends of the water pump, thereby realizing intermittent start and stop control and dynamic speed regulation control of the water pump;

[0034] The PTC driver is connected to the single-chip microcomputer and the PTC heating plate, and is used to convert the single-chip microcomputer control signal into an effective voltage across the PTC heating plate to achieve different heating powers;

[0035] The relay is connected to the single chip microcomputer and the electromagnetic valve, and is used to realize the on-off control of the electromagnetic valve by the high and low level control signals of the single chip microcomputer.

[0036] The method for realizing the room temperature magnetic heat pump control system includes timing matching control, PWM speed regulation control, signal acquisition control, liquid level self-balancing control, magnetic field positioning control, and variable load dynamic control;

[0037] Preferably, the timing matching control method includes the following two operating modes:

[0038] Operation mode 1: Continuous operation mode based on the reverse Brayton regenerative cycle, the servo motor runs continuously, and the third water pump, the first solenoid valve, the second water pump, and the second solenoid valve run intermittently; when the servo motor drives the Halbach internal magnet to rotate to a position near the highest magnetic field, the third water pump and the first solenoid valve are opened to perform a cold flow process; when it rotates to a position near the lowest magnetic field, the second water pump and the second solenoid valve are opened to perform a hot flow process, and all water pumps and solenoid valves are closed at times not near the highest / lowest magnetic field;

[0039] The single-cycle timing is as follows: the servo motor rotates continuously, and the third water pump and the first solenoid valve are turned on 30° before the Halbach inner magnet reaches the highest magnetic field position. The third water pump is turned off after the Halbach inner magnet rotates 30° past the highest magnetic field position, and the first solenoid valve is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the cold flow process; the second water pump and the second solenoid valve are turned on 30° before the Halbach inner magnet reaches the lowest magnetic field position, and the second water pump is turned off after the Halbach inner magnet rotates 30° past the lowest magnetic field position, and the second solenoid valve is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the hot flow process;

[0040] Operation mode 2: intermittent operation mode based on reverse Brayton regenerative cycle. The servo motor operates intermittently, the third water pump, the first solenoid valve, the second water pump, and the second solenoid valve operate intermittently, and the servo motor and the third water pump and the second water pump do not operate at the same time;

[0041] The single-cycle timing is as follows: the rotation of the servo motor drives the Halbach internal magnet to rotate 180°, from the lowest magnetic field position to the highest magnetic field position and then stops, so that the magnetic flux density in the middle pore area changes from 0 to the maximum value, completing a magnetization process of the magnetocaloric material; at the moment the servo motor stops, the third water pump and the first solenoid valve are turned on, and the cold flow process is carried out in a fully magnetized state. After the second flow sensor detects that the heat exchange fluid flow reaches a predetermined value, the third water pump is turned off, and the first solenoid valve is closed with a delay of m seconds to balance the pressure wave inside the pipeline; at the moment the third water pump is turned off, the servo motor is started again. The rotation drives the Halbach internal magnet to rotate 180°, from the highest magnetic field position to the lowest magnetic field position and then stops, so that the magnetic flux density in the middle pore area decreases from the maximum value to 0, completing the demagnetization process of the magnetocaloric material; the second water pump and the second solenoid valve are opened at the moment the servo motor stops, and the heat flow process is carried out in a completely demagnetized state. After the first flow sensor detects that the heat exchange fluid flow reaches a predetermined value, the second water pump is closed, and the second solenoid valve is closed with a delay of m seconds to balance the pressure wave inside the pipeline; at the moment the second water pump is closed, the servo motor is started again to carry out the next cycle of magnetization process.

[0042] Preferably, the PWM speed control includes servo motor frequency control and water pump PWM control;

[0043] During the servo motor frequency modulation control process, the pulse duty cycle sent by the single-chip microcomputer is kept unchanged, and the pulse frequency is changed to change the speed of the servo motor. Specifically, the pulse frequency is adjusted through the progress bar on the serial port screen to realize the servo motor frequency modulation control;

[0044] During the PWM control of the water pump, the pulse frequency sent by the microcontroller is kept unchanged, and the pulse duty cycle is changed to change the speed of the water pump. Specifically, the pulse duty cycle is adjusted through the progress bar on the serial port screen to achieve PWM control of the water pump.

[0045] Preferably, the signal acquisition control includes a temperature sensor module, a liquid level sensor module, a pressure sensor module, a flow sensor module, a metal proximity switch sensor module, a magnetic induction proximity switch sensor, and a servo encoder signal acquisition control;

[0046] During the control process of the temperature sensor module and the liquid level sensor module, the temperature signal and the liquid level signal are input through the A / D conversion module of the single chip microcomputer, and the analog signal data is converted into digital signal data, thereby obtaining the actual temperature value and the liquid level height value;

[0047] During the control process of the pressure sensor module, the current signal output by the pressure sensor module is converted into a voltage signal by the current-to-voltage module, and then input into the single-chip microcomputer A / D conversion module to convert the analog signal data into digital signal data, thereby obtaining the actual pressure value;

[0048] During the control process of the flow sensor module, the flow sensor module uses the timer module input capture function of the single-chip microcomputer, and uses two timers, one for timing n seconds, and the other for capturing external input pulses. Therefore, the frequency of the external input pulse can be calculated by the number of pulses captured within n seconds, and then the actual flow value can be obtained by conversion;

[0049] During the control process of the metal proximity switch sensor module, when the metal proximity switch sensor module is in the high / low magnetic field position, a level jump will occur, generating a switch signal, which is input into the GPIO port of the single-chip microcomputer and read, and controls the timing of the cold / hot flow process in the loop program;

[0050] The magnetic induction proximity switch sensor will have a level jump when the high / low magnetic field position is in place, generating a switch signal, and the switch signal is input into the GPIO port of the single-chip microcomputer to be read to calibrate the initial magnetic field position;

[0051] The servo encoder counts the actual output pulse number of the servo motor, transmits it to the servo driver and the microcontroller, and compares it with the input pulse number sent to the servo motor by the microcontroller to realize feedback and correction of the motion signal.

[0052] Preferably, the liquid level self-balancing control is achieved by collecting the return value of the liquid level sensor module, calculating the absolute value of the difference in the corresponding water tank liquid level position rise value during the cold / hot flow process, and changing the corresponding water pump duty cycle to achieve self-balancing of the water tank liquid level.

[0053] Preferably, the magnetic field positioning control is in the process of high and low magnetic field positioning, and the position of the metal proximity switch sensor module is determined by the position opposite to the magnetic field positioning mark in the high magnetic field and the position opposite to the magnetic field positioning mark in the low magnetic field; the first metal proximity switch sensor is opposite to the magnetic field positioning mark in the high magnetic field, and the second metal proximity switch sensor is opposite to the magnetic field positioning mark in the low magnetic field;

[0054] When performing a room temperature magnetic heat pump reheat cycle, when the Halbach internal magnet rotates to magnetize or demagnetize, whenever the magnetic field positioning mark rotates to the position directly facing the first metal proximity switch sensor, it proves that this position is a high magnetic field position, and at this time the first metal proximity switch sensor sends a high magnetic field position arrival signal to the single chip microcomputer; whenever the magnetic field positioning mark rotates to the position directly facing the second metal proximity switch sensor, it proves that this position is a low magnetic field position, and at this time the second metal proximity switch sensor sends a low magnetic field position arrival signal to the single chip microcomputer;

[0055] In the continuous operation mode, after the metal proximity switch sensor module sends a high / low magnetic field position signal to the microcontroller, it calculates whether the moment of reaching the position is the middle moment of the flow, and calibrates the demagnetization and cold / hot flow timing; in the intermittent operation mode, after the metal proximity switch sensor module sends a high / low magnetic field position signal to the microcontroller, it executes the servo motor duty cycle set to 0 instruction, the servo motor stops, and the cold / hot flow process is carried out.

[0056] Preferably, the variable load dynamic control includes variable cooling load dynamic control and variable heating load dynamic control;

[0057] The variable cooling load in the variable cooling load dynamic control is to change the temperature of the constant temperature water bath at the hot end and change the heat exchange fluid flow on this side by controlling the voltage of the first water pump to achieve different cooling load simulations; the variable cooling load dynamic control is to compare the temperature span at this time with the set temperature span, input the fuzzy PID controller, and perform calculations through the fuzzy PID control algorithm. By controlling the voltage of the second water pump and the third water pump, the heat flow and cold flow circulation flow rates are changed, and the room temperature magnetic heat pump system is controlled to maintain the set temperature span under the current cooling load to achieve dynamic control of variable cooling load;

[0058] The variable heat load in the variable heat load dynamic control is achieved by changing the voltage of the PTC heating plate at the cold end to simulate different heat loads; the variable heat load dynamic control is to compare the temperature span at this time with the set temperature span, input the fuzzy PID controller, and perform calculations through the fuzzy PID control algorithm. By controlling the voltage of the second water pump and the third water pump, the heat flow and cold flow circulation flow rates are changed, and the room temperature magnetic heat pump system is controlled to maintain the set temperature span under the current heat load to achieve dynamic control of variable heat load.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] It can realize human-computer interactive control of the room temperature magnetic heat pump system, carry out coordinated control of the operating timing of the room temperature magnetic heat pump heat recovery cycle and PWM speed control, collect and feedback key parameter signals, realize self-balancing control of the liquid level of the first water tank and the second water tank in the cold flow and hot flow processes, increase the positioning control accuracy of high and low magnetic fields, and realize variable load dynamic control of the room temperature magnetic heat pump system. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a schematic diagram of the structure of the room temperature magnetic heat pump control system involved in the present invention. It should be pointed out that the solid line is the heat exchange fluid flow path, and the dotted line is the control system signal flow;

[0062] Figure 2 This is a timing diagram of the reverse Brayton regenerative cycle continuous operation mode of the room temperature magnetic heat pump system involved in the present invention;

[0063] Figure 3 This is a timing diagram of the intermittent operation mode of the reverse Brayton regenerative cycle of the room temperature magnetic heat pump system involved in the present invention;

[0064] Figure 4 This is a schematic diagram of the reverse Brayton heat recovery cycle of the room temperature magnetic heat pump system involved in the present invention;

[0065] Figure 5 A schematic diagram of the Halbach magnet group structure and the magnetic field positioning mark assembly position involved in the present invention;

[0066] Figure 6 A schematic diagram of the relative positions of the metal proximity switch sensor module and the magnetic field positioning mark involved in the present invention;

[0067] Figure 7 This is a control logic diagram of the room temperature magnetic heat pump control system involved in the present invention. DETAILED DESCRIPTION

[0068] The specific implementation modes of the present invention are further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0069] like Figure 1 As shown, a room temperature magnetic heat pump control system of the present embodiment is used to control the heat recovery cycle operation process of the room temperature magnetic heat pump system, including a power module 6, a sensor module 13, a single-chip microcomputer 14, an actuator module 15, and a serial port screen 16; the signal of the sensor module 13 is transmitted to the single-chip microcomputer 14 through the GPIO port of the single-chip microcomputer 14, the single-chip microcomputer 14 is used for the overall coordinated control of the system, and the actuator module 15 is used to execute the control instructions issued by the single-chip microcomputer 14; the serial port screen 16 is used to realize human-computer interaction, and the power module 6 is used to power the entire system.

[0070] The room temperature magnetic heat pump includes the following four flow paths:

[0071] Connection relationship of cold flow path: the two ends of the active magnetic regenerator 2 are connected to the first solenoid valve 7 and the second one-way valve 22, the other end of the first solenoid valve 7 is connected to the high-temperature side inlet of the first heat exchanger 8, the high-temperature side outlet of the first heat exchanger 8 is connected to the first water tank 11, the other end of the second one-way valve 22 is connected to the third water pump 17, and the other end of the third water pump 17 is connected to the second water tank 18; the cold flow path is used to realize the pumping of the heat exchange fluid from the second water tank 18 through the active magnetic regenerator 2 to the first water tank 11;

[0072] Connection relationship of heat flow path: two ends of the active magnetic regenerator 2 are connected to the first one-way valve 5 and the second solenoid valve 21, the other end of the first one-way valve 5 is connected to the second water pump 12, the other end of the second water pump 12 is connected to the first water tank 11, the other end of the second solenoid valve 21 is connected to the second heat exchanger 19, and the other end of the second heat exchanger 19 is connected to the second water tank 18; the heat flow path is used to realize the pumping of the heat exchange fluid from the first water tank 11 through the active magnetic regenerator 2 to the second water tank 18;

[0073] The hot end heat exchange flow connection relationship: the two ends of the first water pump 9 are connected to the constant temperature water bath 10 and the low temperature side inlet of the first heat exchanger 8, and the other side of the constant temperature water bath 10 is connected to the low temperature side outlet of the first heat exchanger 8;

[0074] The cold end heat exchange flow path connection relationship is: the PTC heating plate 20 is attached to the surface of the second heat exchanger 19, the hot flow fluid flows through the second heat exchanger 19 to achieve heat exchange, and the thermal compensation method is used to simulate the heat load and measure the cooling capacity.

[0075] The first solenoid valve 7 and the second solenoid valve 21 are used for on-off control of the system flow path; the first one-way valve 5 is used to prevent the hot flow fluid from flowing back under the internal resistance of the active magnetic regenerator 2, and the second one-way valve 22 is used to prevent the cold flow fluid from flowing back under the internal resistance of the active magnetic regenerator 2; the constant temperature water bath 10 is used to provide a heat dissipation environment at the hot end and measure the heating capacity at the hot end; the first heat exchanger 8 is used to provide a heat exchange environment for the cold flow fluid and the fluid in the constant temperature water bath 10, using a countercurrent heat exchange form; the second heat exchanger 19 is used to provide a heat exchange environment for the hot flow fluid and the PTC heating plate 20; the PTC heating plate 20 is used to provide a cold end heat load for the room temperature magnetic heat pump system, and realize the thermal compensation method to measure the cooling capacity; the first water tank 11 is used to store the hot end heat exchange fluid, and the second water tank 18 is used to store the cold end heat exchange fluid; the first water pump 9, the second water pump 12, and the third water pump 17 are used to provide power for the hot flow and cold flow fluids.

[0076] The active magnetic regenerator 2 is located in the central pore 30 inside the Halbach magnet group 1. Figure 1 As shown. The Halbach magnet group 1 includes a Halbach inner magnet 28 and a Halbach outer magnet 29. The Halbach inner magnet 28 is connected to a driven gear 23. The driven gear 23 and the driving gear 25 are connected through a toothed belt 24. The driving gear 25 is located on the output shaft of a servo motor 26. The servo motor 26 drives the Halbach inner magnet 28 to rotate through the above transmission connection. The servo motor 26 is used to provide power for the Halbach magnet group 1. The servo encoder 27 is used to realize the feedback of the position signal and the speed signal. The Halbach inner magnet 28 is located in the Halbach outer magnet 29. Figure 5As shown, through the relative movement of the Halbach inner magnet 28 and the Halbach outer magnet 29, a changing magnetic field is formed in the middle pore area 30 of the Halbach inner magnet 28 and the Halbach outer magnet 29; the active magnetic regenerator 2 is placed in the middle pore area 30, and a magnetic field positioning mark 3 is provided on the magnet block of the Halbach inner magnet 28, which cooperates with the first metal proximity switch sensor 32 and the second metal proximity switch sensor 33 to achieve high / low magnetic field positioning, and the first metal proximity switch sensor 32 and the second metal proximity switch sensor 33 are fixed on the fixed disk 34 at a distance of 180°, and the fixed disk 34 is fixed on the room temperature magnetic heat pump stand, as shown in FIG. Figure 6 shown.

[0077] The magnetic field positioning mark 3 on the Halbach internal magnet 28 rotates with the internal magnet, and rotates to a position directly opposite to the first metal proximity switch sensor 32. The first metal proximity switch sensor 32 sends a switch signal to the single-chip microcomputer 14, indicating that the magnetic field position is a high magnetic field at this time; it rotates to a position directly opposite to the second metal proximity switch sensor 33. The second metal proximity switch sensor 33 sends a switch signal to the single-chip microcomputer 14, indicating that the magnetic field position is a low magnetic field at this time.

[0078] The single-chip microcomputer 14 is connected to the sensor module 13, the actuator module 15, and the serial port screen 16. The serial port screen 16 displays and stores the signal data collected by the sensor module in real time. After receiving the signals from the sensor module 13 and the serial port screen 16, the single-chip microcomputer 14 sends a control signal to the actuator module 15 to realize closed-loop control of the room temperature magnetic heat pump system. The single-chip microcomputer 14 is not limited to C51 series, STM series single-chip microcomputers, PLCs, etc.

[0079] The sensor module 13 includes a temperature sensor module 35 , a pressure sensor module 36 , a flow sensor module 37 , a liquid level sensor module 38 , a metal proximity switch sensor module 4 , a magnetic induction proximity switch sensor 31 , and a servo encoder 27 .

[0080] The actuator module 15 includes a servo motor 26 , a first water pump 9 , a second water pump 12 , a third water pump 17 , a PTC heating plate 20 , a first solenoid valve 7 , a second solenoid valve 21 , a servo driver 39 , a photoelectric coupler 40 , a water pump driver 41 , a PTC driver 42 , and a relay 43 .

[0081] The temperature sensor module 35 includes multiple temperature sensors T1~T11, which are respectively used to monitor the hot end temperature of the active magnetic regenerator 2, the cold end temperature of the active magnetic regenerator 2, the temperature of the first water tank 11, the temperature of the second water tank 18, the ambient temperature, the low-temperature side inlet temperature of the first heat exchanger 8, the low-temperature side outlet temperature of the first heat exchanger 8, the high-temperature side inlet temperature of the first heat exchanger 8, the high-temperature side outlet temperature of the first heat exchanger 8, the inlet temperature of the second heat exchanger 19, and the outlet temperature of the second heat exchanger 19; the temperature sensor is not limited to T-type, K-type thermocouples, PT100, armored thermocouples, etc.

[0082] The pressure sensor module 36 includes a plurality of pressure transmitters P1 to P4, which respectively monitor the pumping pressures of the second water pump 12 and the third water pump 17 and the pressure of each heat exchange fluid flowing out of the active magnetic regenerator 2. If the pressure deviates from the threshold, the system alarms. The pressure sensor is not limited to glass micro-melting type, single crystal silicon type, temperature-pressure integrated type, shell explosion-proof type pressure transmitter, etc.

[0083] The flow sensor module 37 includes a first flow sensor FS1, a second flow sensor FS2, and a third flow sensor FS3, which respectively monitor the heat exchange fluid flow rate of the hot flow process, the heat exchange fluid flow rate of the cold flow process, and the heat exchange flow rate of the heat exchange fluid on the side of the water bath 10 through the first heat exchanger 8 and the cold flow fluid; the flow sensor is not limited to a Hall flow meter, an ultrasonic flow meter, an electromagnetic flow meter, etc. If the three flow sensors FS1 to FS3 monitor that the deviation between the actual value of the system flow signal and the set value is greater than the alarm threshold, the system alarms and is forced to shut down.

[0084] The liquid level sensor module 38 includes a first liquid level sensor LLS1 and a second liquid level sensor LLS2, which are used to measure the liquid levels of the first water tank 11 and the second water tank 18 respectively; the liquid level sensor is not limited to a magnetic float liquid level sensor, a immersion liquid level sensor, an ultrasonic liquid level sensor, etc.

[0085] The metal proximity switch sensor module 4 includes a first metal proximity switch sensor 32 for realizing high magnetic field positioning and a second metal proximity switch sensor 33 for realizing low magnetic field positioning. The proximity switch sensor is not limited to an inductive proximity switch, a capacitive proximity switch, a Hall proximity switch, a photoelectric proximity switch, a pyroelectric proximity switch, an ultrasonic and macro proximity switch, a reed proximity switch, etc. In the present embodiment, a photoelectric proximity switch sensor is adopted.

[0086] The metal proximity switch sensor module 4 is combined with the magnetic induction proximity switch sensor 31 to mark the high magnetic field and low magnetic field positions of the Halbach magnet group 1 at the initial moment, and provide a signal indicating that the magnetization / demagnetization position is in place during the cycle.

[0087] The servo motor 26 controls the periodic movement of the Halbach inner magnet 28 of the room temperature magnetic heat pump. Each time the Halbach inner magnet 28 rotates 180°, a system magnetization or demagnetization process is completed. The servo motor 26 is not limited to an AC synchronous servo motor, an AC asynchronous servo motor, etc.

[0088] The servo encoder 27 is connected to the servo motor 26 and the servo driver 39 , and feeds back the position and speed signals of the servo motor 26 to the servo driver 39 and the single chip microcomputer 14 .

[0089] The first water pump 9, the second water pump 12 and the third water pump 17 are respectively used to drive the circulation of the heat exchange fluid on the constant temperature water bath 10 side, the circulation of the heat exchange fluid in the hot flow process, and the circulation of the heat exchange fluid in the cold flow process; the water pump is not limited to a DC brush gear pump, a DC brushless gear pump, a diaphragm pump, a plunger pump, a piston pump, etc. In this embodiment, a DC brush motor gear pump is used.

[0090] The PTC heating sheet 20 is attached to the surface of the second heat exchanger 19 to provide an external heat load to the cold end of the room temperature magnetic heat pump system, thereby realizing the measurement of cooling capacity using a thermal compensation method.

[0091] The first solenoid valve 7 and the second solenoid valve 21 are both connected to the relay 43, and are used to control the on / off of the cold / hot flow path, respectively, to ensure the timing of the cold and hot flow, and are not limited to ordinary solenoid valves, pneumatic solenoid valves, hydraulic solenoid valves, etc. Further, during the control process of the first solenoid valve 7 and the second solenoid valve 21, the single-chip microcomputer 14 sends high and low level signals to the relay 43, and the high and low level signals are obtained by setting and resetting the corresponding ports in the control program, thereby controlling the on / off of the first solenoid valve 7 and the second solenoid valve 21.

[0092] The PTC driver 42 is connected to the single chip microcomputer 14 and the PTC heating plate 20, and is used to convert the control signal of the single chip microcomputer 14 into an effective voltage across the PTC heating plate 20 to achieve different heating powers.

[0093] The relay 43 is used to realize the on-off control of the first solenoid valve 7 and the second solenoid valve 21 by the high and low level control signals of the single chip microcomputer 14; the relay 43 is not limited to electromagnetic relays, solid state relays, time relays, etc.

[0094] like Figure 7As shown, the output end of the servo driver 39 is respectively connected to the single-chip microcomputer 14 and the servo motor 26, and is used to receive the control signal of the single-chip microcomputer 14, drive the servo motor 26 to rotate a corresponding angle according to the actual equivalent number of pulses (the product of the number of single-chip microcomputer pulses and the electronic gear ratio), and realize the reception of the feedback signal of the servo encoder 27, and the feedback signal can be transmitted to the single-chip microcomputer 14 through the signal terminal of the servo driver 39; the servo driver 39 is not limited to a servo driver with a brake, a servo driver without a brake, etc. In this embodiment, a servo driver with a brake is used.

[0095] The single-chip microcomputer 14 is connected to the servo driver 39 via a photoelectric coupler 40. The photoelectric coupler 40 is used to achieve signal amplification and photoelectric isolation protection, and is not limited to high-speed photoelectric couplers, low-speed photoelectric couplers, etc. In this embodiment, a high-speed photoelectric coupler is used to amplify the PWM control signal emitted by the single-chip microcomputer 14 to 24V to drive the servo motor 26, and play a role in photoelectric isolation system protection; further, the single-chip microcomputer 14 and the servo driver 39 are directly connected to achieve secondary transmission of the servo encoder 27 feedback signal to the single-chip microcomputer 14 via the servo driver 39.

[0096] The water pump driver 41 is connected to the single chip microcomputer 14, and is used to convert the PWM control signal sent by the single chip microcomputer 14 into an effective voltage across the first water pump 9, the second water pump 12, and the third water pump 17, so as to realize the start and stop control and speed control of the three water pumps; the water pump driver 41 is not limited to a DC brush motor driver, a DC brushless motor driver, etc. In this embodiment, a DC brush motor driver is used.

[0097] The serial port screen 16 is connected to the single-chip microcomputer 14, and is used to realize real-time display and storage of the signal collected by the sensor module 13 to the single-chip microcomputer 14, and to send a control command instruction set to the single-chip microcomputer 14. The single-chip microcomputer 14 further parses the control command instruction set and sends a corresponding control signal to the actuator module 15. The control signal includes a high and low level signal and a pulse signal, and adjusts the PWM frequency and duty cycle to achieve a predetermined motor speed, water pump speed, and PTC heating temperature. The serial port screen 16 is not limited to a capacitive serial port screen, a resistive serial port screen, etc. In this embodiment, a capacitive serial port screen is used.

[0098] The power supply module 6 includes a 220V AC power supply, a 24V DC power supply, a 5V DC power supply, and a 3.3V DC power supply. The 220V AC power supply supplies power to the servo motor 26 and the servo driver 39; the 24V DC power supply supplies power to the first water pump 9, the second water pump 12, the third water pump 17, the PTC heating plate 20, the servo motor 26CN1 port, the first solenoid valve 7, the second solenoid valve 21, the pressure sensor module 36, the flow sensor module 37, the liquid level sensor module 38, the metal proximity switch sensor module 4, the magnetic induction proximity switch sensor 31, the photoelectric coupler 40, the water pump driver 41, and the PTC driver 42; the 5V DC power supply supplies power to the serial port screen 16 and the relay 43, and the 3.3V DC power supply supplies power to the single-chip computer 14.

[0099] Specifically, in a room temperature magnetic heat pump control method provided by the present invention, the timing matching control is implemented by the following steps:

[0100] Through the serial port screen 16 control interface, the operation mode is set to continuous / intermittent, the magnetization / demagnetization time, the cold / hot flow time, the servo motor 26 speed, the water pump (9, 12, 17) speed, and the system alarm threshold.

[0101] Furthermore, the serial port screen command is transmitted to the single-chip computer 14 through serial port communication. After being processed by the internal control algorithm, the PWM control signal is output to the photocoupler 40 and the water pump driver 41. The voltage of the PWM control signal sent by the single-chip computer 14 is 3.3V. After the photocoupler 40 receives the PWM signal, the control signal is boosted to 24V. The frequency and duty cycle of the pulse square wave remain unchanged. The servo driver 39CN1 port is input to achieve different speeds of the servo motor 26 through different pulse square wave frequencies. The duration of the pulse square wave is the running time of the servo motor. After the water pump driver 41 receives the PWM signal, different effective voltages at both ends of the water pump are achieved through different pulse square wave duty cycles, thereby achieving different speeds. The above steps are used to realize the set operation of the room temperature magnetic heat pump system and complete the correct timing matching.

[0102] In this embodiment, for the continuous operation mode, the servo motor 26 operates continuously, and the third water pump 17, the first solenoid valve 7, the second water pump 12, and the second solenoid valve 21 operate intermittently, both of which are turned on near the highest magnetic field or the lowest magnetic field, and closed at other times.

[0103] Specifically, the working sequence of a single cycle of the continuous operation mode is as follows: the servo motor 26 rotates continuously, the Halbach internal magnet 28 reaches the position 30° before the highest magnetic field position, the third water pump 17 and the first solenoid valve 7 are turned on, and the cold flow process is started when the magnetization is not complete, such as Figure 2In the time period (t2+t3) shown in FIG. 1 , after the Halbach internal magnet 28 rotates to the position of the highest magnetic field by 30°, the third water pump 17 is closed, and the first solenoid valve 7 is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the cold flow process; before the Halbach internal magnet 28 reaches the position of the lowest magnetic field by 30°, the second water pump 12 and the second solenoid valve 21 are opened, and the hot flow process is started before the demagnetization is complete, as shown in FIG. Figure 2 In the time period (t5+t6) shown, after the Halbach internal magnet 28 rotates past the 30° position of the lowest magnetic field, the second water pump 12 is closed and the second solenoid valve 21 is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the heat flow process. Figure 2 The other time periods shown: (t1+t2) time period is the magnetization time (part), and (t3+t4+t5) time period is the demagnetization time.

[0104] In this embodiment, for the intermittent operation mode, the servo motor 26 operates intermittently, the third water pump 17, the first solenoid valve 7, the second water pump 12, and the second solenoid valve 21 operate intermittently, and the servo motor 26 and the third water pump 17 and the second water pump 12 do not operate at the same time.

[0105] Specifically, the working sequence of a single cycle of the intermittent operation mode is as follows: the servo motor 26 rotates to drive the Halbach inner magnet 28 to rotate 180° from the lowest magnetic field position to the highest magnetic field position and then stops, so that the magnetic flux density in the middle pore area 30 (where the active magnetic regenerator is placed) changes from 0 to the maximum magnetic field strength value H max , completing a magnetization process of the magnetocaloric material, corresponding to Figure 3 t1 time period; the servo motor 26 stops at the moment the third water pump 17, the first solenoid valve 7 is opened, the magnetocaloric material and the heat exchange fluid cold flow process in the high magnetic field state, corresponding to Figure 3 after the second flow sensor FS2 detects that the heat exchange fluid flow rate reaches a predetermined value, the third water pump 17 is closed, and the first solenoid valve 7 is closed with a delay of m seconds to balance the pressure wave inside the pipeline.

[0106] Furthermore, when the third water pump 17 is turned off, the servo motor 26 is started again, and the Halbach inner magnet 28 is rotated and driven to rotate 180° from the highest magnetic field to the lowest magnetic field and then stop, so that the magnetic flux density in the middle pore area 30 (where the active magnetic regenerator is placed) decreases from the maximum value to 0, completing a demagnetization process of the magnetocaloric material, corresponding to Figure 3The t3 time period; the second water pump 12 and the second solenoid valve 21 are opened at the moment when the servo motor 26 stops, and the heat flow process of the magnetocaloric material and the heat exchange fluid is carried out in the low magnetic field state. After the first flow sensor FS1 detects that the heat exchange fluid flow rate reaches the predetermined flow rate, the second water pump 12 is closed, and the second solenoid valve 21 is closed with a delay of m seconds to balance the pressure wave inside the pipeline, corresponding to Figure 3 The t4 time period;

[0107] Furthermore, at the moment when the second water pump 12 is turned off, the servo motor 26 is started again to perform the magnetization process of the next cycle.

[0108] Specifically, the PWM speed control in the control method of the room temperature magnetic heat pump control system involved in the present invention includes servo motor frequency modulation control and water pump PWM control.

[0109] Furthermore, the frequency modulation control of the servo motor 26 is realized by the following method: using the output comparison function of the timer module of the single-chip microcomputer 14 to output a pulse square wave, and realizing the frequency modulation and speed regulation of the servo motor 26 by adjusting the PWM pulse frequency and the electronic gear ratio of the servo driver 39. The specific steps are as follows:

[0110] The high-speed pulse sent by the single-chip microcomputer 14 is input into the servo driver 39 after being boosted by the photoelectric coupler 40, and the electronic gear ratio of the servo driver 39 is configured to realize the stepping motion of the servo motor 26 which is positively correlated with the pulse frequency; the servo encoder 27 feeds back the position and speed signal to the servo driver 39, obtains the number of feedback pulses of the servo encoder 27, and inputs it into the single-chip microcomputer 14 through the servo driver 39CN1 terminal block, and the single-chip microcomputer 14 calculates the difference between the number of sent pulses and the number of feedback pulses of the servo encoder 27; according to the control pulse deviation value, combined with the fuzzy PID control algorithm, the switch amplification gain coefficient, the differential gain coefficient, and the integral gain coefficient of the servo driver 39 are set to realize the servo motor 26 to accurately and quickly follow the position command pulse sent by the single-chip microcomputer 14, and realize full closed-loop control; as a specific embodiment, the pulse frequency sent by the single-chip microcomputer 14 is 100kHz, and the electronic gear ratio of the servo driver 39 is 240.

[0111] Furthermore, the water pump PWM control is achieved by the following method:

[0112] During the PWM control of the water pump, the single-chip microcomputer sends a pulse square wave with a fixed frequency and an adjustable duty cycle to achieve PWM speed control; as a specific embodiment, the single-chip microcomputer sends a pulse square wave with a fixed frequency of 10kHz and a duty cycle of 0 to 100%, which is input into the water pump driver 41. By changing the duty cycle, the effective voltage value at both ends of the water pump is changed, thereby achieving PWM speed control of the water pump.

[0113] The control method achieves a duty cycle accuracy of 0.125% and a voltage accuracy of 0.03V, which greatly ensures the accuracy of the liquid level adjustment balance of the first water tank 12 and the second water tank 18, and avoids the internal temperature fluctuation of the active magnetic regenerator caused by flow imbalance, thereby adversely affecting the overall temperature span.

[0114] The specific speed regulation is realized by the serial port screen 16. The interface of the serial port screen 16 is designed by VisualTFT software, and the driver is written by Keil software. After being compiled, it is burned to the single-chip computer 14 through the USART serial port for operation. The servo motor 26 is controlled by variable frequency speed regulation through the progress bar, and the water pump (9, 12, 17) is controlled by PWM speed regulation.

[0115] As a specific embodiment, in a room temperature magnetic heat pump control method provided by the present invention, signal acquisition control is implemented by the following steps:

[0116] The temperature sensor module 35, the pressure sensor module 36, and the liquid level sensor module 38 are input through the single-chip microcomputer A / D conversion module, and the flow sensor module 37 signal is obtained through the input capture function of the timer module of the single-chip microcomputer 14. The temperature, pressure, liquid level, and flow data after calculation and conversion will be displayed on the serial port screen 16 through serial port communication.

[0117] Specifically, during the control process of the temperature sensor module 35 and the liquid level sensor module 38, the temperature signal and the liquid level signal are input into the single-chip microcomputer 14 through the A / D conversion module of the single-chip microcomputer, and the analog signal data is converted into digital signal data, thereby obtaining the actual temperature value and the liquid level height value; if a sudden rise / drop in temperature occurs during the non-demagnetization time period, or a sudden rise / drop in liquid level occurs during the non-cold / hot flow time period, and the threshold is exceeded, the system alarms.

[0118] Specifically, the current signal output by the pressure sensor module 36 is converted into a voltage signal by a current-to-voltage module, and input into an A / D conversion module of the single-chip microcomputer to convert the analog signal data into digital signal data, thereby obtaining the actual pressure value.

[0119] Specifically, the flow sensor module 37 adopts the input capture function of the timer module of the single-chip microcomputer 14, and adopts two timers, one for timing n seconds and the other for capturing external input pulses. Therefore, the frequency of the external input pulse can be calculated by the number of pulses captured within n seconds, and then the flow values ​​of the three flow sensors FS1~FS3 can be obtained by conversion.

[0120] Specifically, when the metal proximity switch sensor module 4 is in the high / low magnetic field position, a level jump will occur to generate a switch signal, which is input into the GPIO port (input and output interface) of the microcontroller and read to control the timing of the cold / hot flow process in the cycle program.

[0121] Specifically, the magnetic induction proximity switch sensor 31 will experience a level jump when the high / low magnetic field position is in place, generating a switch signal, and this switch signal is input into the GPIO port (input and output interface) of the microcontroller to be read to calibrate the initial magnetic field position.

[0122] Specifically, the servo encoder 27 counts the actual pulse number of the motor, transmits it to the servo driver 39 and the single-chip microcomputer 14, and compares it with the planned pulse number to achieve feedback and correction of the motion signal.

[0123] The communication protocol between the serial port screen 16 and the single-chip microcomputer 14 is not limited to the RS232 bus communication technology, and the baud rate is not limited to 115200 bps.

[0124] Specifically, in a room temperature magnetic heat pump control method provided by the present invention, liquid level self-balancing control is achieved by the following methods:

[0125] Collect the return value of the liquid level sensor module 38, calculate the absolute value of the difference between the two liquid level positions, and change the change in the corresponding water pump duty cycle to change the corresponding flow rate. The specific steps are as follows:

[0126] The liquid level data of the first liquid level sensor LLS1 and the second liquid level sensor LLS2 at the same cycle position are obtained.

[0127] The difference between the data of the first liquid level sensor LLS1 and the second liquid level sensor LLS2 before and after a single hot / cold flow is calculated. This value can represent the amplitude of the liquid level rise in the first water tank 11 / the second water tank 18 during a single hot / cold flow process.

[0128] According to the difference in the liquid level sensors, in a single cycle, if the second water tank rises more than the first water tank, the duty cycle of the second water pump 12 should be reduced, and the duty cycle of the third water pump 17 should be increased; if the first water tank rises more than the second water tank, the duty cycle of the third water pump 17 should be reduced, and the duty cycle of the second water pump 12 should be increased to achieve self-balancing of the liquid levels in the water tanks at both ends.

[0129] The degree of duty cycle reduction or increase is related to the absolute value of the change in the single flow process of the two liquid level sensors. If the absolute value is within 1mm, the amplitude of duty cycle reduction or increase is 0.125%; if the absolute value is between 1mm and 5mm, the amplitude of duty cycle reduction or increase is 0.25%; if the absolute value is between 5mm and 10mm, the amplitude of duty cycle reduction or increase is 0.5%; if the absolute value is between 10mm and 20mm, the amplitude of duty cycle reduction or increase is 1%; if the absolute value is between 20mm and 50mm, the amplitude of duty cycle reduction or increase is 2.5%; if the absolute value exceeds 50mm, an alarm message is issued, the system is shut down, and the temperature evolution process is re-monitored to avoid excessive fluctuations in the temperature curve during the period of liquid level imbalance.

[0130] Specifically, in a room temperature magnetic heat pump control method provided by the present invention, magnetic field positioning control is achieved by the following steps:

[0131] The metal proximity switch sensors (32, 33) are mounted on a fixed disk 34, the diameter of the fixed disk 34 is equal to the diameter of the Halbach inner magnet 28, and the positions of the metal proximity switch sensors (32, 33) are determined by the positions opposite to the magnetic field positioning mark 3 in a high magnetic field and the positions opposite to the magnetic field positioning mark 3 in a low magnetic field; the first metal proximity switch sensor 32 is opposite to the magnetic field positioning mark 3 in a high magnetic field, and the second metal proximity switch sensor 33 is opposite to the magnetic field positioning mark 3 in a low magnetic field.

[0132] Therefore, when the room temperature magnetic heat pump regenerative cycle is performed, when the Halbach internal magnet 28 rotates to magnetize or demagnetize, every time the magnetic field positioning mark 3 rotates to the position directly opposite the first metal proximity switch sensor 32, it is proved that this position is a high magnetic field position. At this time, the first metal proximity switch sensor 32 sends a high magnetic field position arrival signal to the single chip computer 14. In the continuous operation mode, the rotation speed of the servo motor 26 is calibrated with this position as the center, and it is compared whether this moment is the middle moment of the predetermined flow process. If not, the flow start and end time should be adjusted to achieve cold / hot flow calibration to avoid timing confusion; in the intermittent operation mode, the duty cycle of the servo motor 26 is set to 0, the servo motor 26 stops, and the cold flow process is performed.

[0133] Whenever the magnetic field positioning mark 3 rotates to the position facing the second metal proximity switch sensor 33, it proves that this position is a low magnetic field position. At this time, the second metal proximity switch sensor 33 sends a low magnetic field in place signal to the single chip 14. In the continuous operation mode, the rotation speed of the servo motor 26 is calibrated with this position as the center, and it is compared whether this moment is the middle moment of the predetermined flow process. If not, the flow start and end time should be adjusted to achieve cold / hot flow calibration to avoid timing confusion; in the intermittent operation mode, the duty cycle of the servo motor 26 is set to 0, the servo motor 26 stops, and the hot flow process is carried out.

[0134] Specifically, in a room temperature magnetic heat pump control method provided by the present invention, variable load dynamic control is achieved by the following methods:

[0135] The variable cooling load in the dynamic control of variable cooling load is achieved by changing the temperature of the constant temperature water bath 10 at the hot end and changing the flow rate of the heat exchange fluid on this side by controlling the voltage of the first water pump 9 to realize different cooling load simulations; the dynamic control of variable cooling load is to compare the temperature difference between the first water tank 11 and the second water tank 18 at this time with the set temperature span, input it into the fuzzy PID controller, and perform calculations through the fuzzy PID control algorithm. By controlling the voltage of the second water pump 12 and the third water pump 17, the heat flow and cold flow circulation flow rates are changed, and the room temperature magnetic heat pump system is controlled to maintain the set temperature span under the current cooling load to achieve dynamic control of variable cooling load.

[0136] The variable heat load in the dynamic control of variable heat load is achieved by changing the voltage of the PTC heating plate 20 at the cold end to simulate different heat loads; the dynamic control of variable heat load is to compare the temperature difference between the first water tank 11 and the second water tank 18 at this time with the set temperature span, input it into the fuzzy PID controller, and perform calculations through the fuzzy PID control algorithm. By controlling the voltage of the second water pump 12 and the third water pump 17, the heat flow and cold flow circulation flow rates are changed, and the room temperature magnetic heat pump system is controlled to maintain the set temperature span under the current heat load to achieve dynamic control of variable heat load.

[0137] Specifically, the timing of the continuous operation mode of the room temperature magnetic heat pump regenerative cycle is as follows: Figure 2 As shown, the time period (t1+t2) is the magnetization time (part), which is the same as Figure 4 The AB process shown in the figure corresponds to the cold flow time (t2+t3). Figure 4 The BD process shown in the figure corresponds to the demagnetization time (t3+t4+t5). Figure 4 The DE process shown in the figure corresponds to the heat flow time (t5+t6). Figure 4 The EA process shown corresponds to the following.

[0138] Specifically, the timing of the intermittent operation mode of the room temperature magnetic heat pump regenerative cycle is as follows: Figure 3 As shown, t1 is the magnetization time, which is Figure 4 The AB process shown in the figure corresponds to t2, which is the cold flow time. Figure 4 The BD process shown in the figure corresponds to t3, which is the demagnetization time. Figure 4 The DE process shown in the figure corresponds to t4, which is the heat flow time. Figure 4 The EA process shown corresponds to the following.

[0139] Specifically, the temperature-entropy change of the magnetocaloric material during the heat recovery process of the room temperature magnetic heat pump heating cycle is as follows: Figure 4 As shown, T hot and T env are the hot end temperature and the ambient temperature respectively, H1 is the high magnetic field line, and H2 is the low magnetic field line. AB corresponds to the isentropic magnetization process in the reverse Brayton heat recovery cycle, and the temperature of the magnetocaloric material rises; BD corresponds to the cold flow process in the reverse Brayton heat recovery cycle, through which the heat generated by magnetization is stored in the heat exchange fluid and released to the outside in the first heat exchanger 8 (hot end heat exchanger); DE corresponds to the isentropic demagnetization process in the reverse Brayton heat recovery cycle, and the temperature of the magnetocaloric material decreases; EA corresponds to the heat flow process in the reverse Brayton heat recovery cycle. The EA process returns the remaining heat of the heat exchange fluid after heat exchange in the second heat exchanger 19 (cold end heat exchanger) to the magnetocaloric material, and the amount of recovered heat is Q R It is the area enclosed by the quadrilateral CDHI, which is also equal to the area enclosed by the quadrilateral AGJK. The heat recovery direction is from CDHI to AGJK, that is, the heat exchange fluid returns the heat stored in the CD process during cold flow to the magnetocaloric material through the GA process during hot flow, so that the magnetocaloric material has a higher starting temperature before the next magnetization, so as to achieve the purpose of widening the temperature span of the system. The maximum heating capacity of a single cycle is Q H is the area enclosed by quadrilateral BCIK. The reheat cycle direction is counterclockwise. In each reheat cycle, the system temperature span gradually increases until the heat exchange at the cold and hot ends reaches a stable state of dynamic equilibrium, and the system temperature span fluctuates around a stable value.

[0140] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made by technical personnel in this field within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A room temperature magnetic heat pump control system, used to control the heat recovery cycle operation process of a room temperature magnetic heat pump, characterized in that: It includes a power module (6), a sensor module (13), a single chip microcomputer (14), an actuator module (15), and a serial port screen (16); The sensor module (13) is used to collect temperature, pressure, flow, liquid level, magnetic field position, and motor operation status signals, and transmit the collected signal data to the single-chip computer (14); the serial port screen (16) is connected to the single-chip computer (14) to display and store the signal data collected by the sensor in real time; after receiving the signals from the sensor module (13) and the serial port screen (16), the single-chip computer (14) sends a corresponding control signal to the actuator module (15), thereby realizing closed-loop control of the room temperature magnetic heat pump system; The room temperature magnetic heat pump comprises the following four flow paths: a hot end heat exchange flow path, a hot flow flow path, a cold flow flow path, and a cold end heat exchange flow path; The hot end heat exchange flow path connection method: the two ends of the first water pump (9) are connected to the constant temperature water bath (10) and the low temperature side inlet of the first heat exchanger (8), and the other end of the constant temperature water bath (10) is connected to the low temperature side outlet of the first heat exchanger (8); The heat flow path connection method is as follows: the two ends of the active magnetic regenerator (2) are connected to the first one-way valve (5) and the second solenoid valve (21), the other end of the first one-way valve (5) is connected to the second water pump (12), the other end of the second water pump (12) is connected to the first water tank (11), the other end of the second solenoid valve (21) is connected to the second heat exchanger (19), and the other end of the second heat exchanger (19) is connected to the second water tank (18); the heat flow path is used to realize the pumping of the heat exchange fluid from the first water tank (11) through the active magnetic regenerator (2) to the second water tank (18); Cold flow path connection method: the two ends of the active magnetic regenerator (2) are connected to the first solenoid valve (7) and the second one-way valve (22), the other end of the first solenoid valve (7) is connected to the high-temperature side inlet of the first heat exchanger (8), the high-temperature side outlet of the first heat exchanger (8) is connected to the first water tank (11), the other end of the second one-way valve (22) is connected to the third water pump (17), and the other end of the third water pump (17) is connected to the second water tank (18); the cold flow path is used to realize the pumping of the heat exchange fluid from the second water tank (18) through the active magnetic regenerator (2) to the first water tank (11); Cold end heat exchange flow path connection method: the PTC heating sheet (20) is attached to the surface of the second heat exchanger (19), the hot flow fluid flows through the second heat exchanger (19) to achieve heat exchange, and the heat compensation method is used to achieve heat load simulation and cooling capacity measurement; The active magnetic regenerator (2) is located at a central pore (30) inside the Halbach magnet group (1). The Halbach magnet group (1) comprises a Halbach inner magnet (28) and a Halbach outer magnet (29). The Halbach inner magnet (28) is located inside the Halbach outer magnet (29). The two are in a nested double-layer ring shape. The Halbach outer magnet (29) is fixed to a frame. The Halbach inner magnet (28) is connected to a driven gear (23). The driven gear (23) is connected to a driving gear (25) via a toothed belt (24). The driving gear (25) is located at a position between the servo motor (2 6) output shaft; the servo motor (26) provides power to the Halbach inner magnet (28) through the above-mentioned transmission connection, and forms a changing magnetic field in the middle pore area (30) of the Halbach inner magnet (28) and the Halbach outer magnet (29) through the relative movement of the Halbach inner magnet (28) and the Halbach outer magnet (29), and the active magnetic regenerator (2) is placed in the middle pore area (30). A magnetic field positioning mark (3) is provided on the magnet block of the Halbach inner magnet (28), and the high / low magnetic field positioning is realized in cooperation with the first metal proximity switch sensor (32) and the second metal proximity switch sensor (33).

2. A room temperature magnetic heat pump control system according to claim 1, characterized in that: The sensor module (13) comprises a temperature sensor module (35), a pressure sensor module (36), a flow sensor module (37), a liquid level sensor module (38), a metal proximity switch sensor module (4), a magnetic induction proximity switch sensor (31), and a servo encoder (27); The temperature sensor module (35) includes a plurality of temperature sensors T1-T11, which are respectively used to monitor the hot end temperature of the active magnetic regenerator (2), the cold end temperature of the active magnetic regenerator (2), the temperature of the first water tank (11), the temperature of the second water tank (18), the ambient temperature, the low temperature side inlet temperature of the first heat exchanger (8), the low temperature side outlet temperature of the first heat exchanger (8), the high temperature side inlet temperature of the first heat exchanger (8), the high temperature side outlet temperature of the first heat exchanger (8), the second heat exchanger (19) inlet temperature, and the second heat exchanger (19) outlet temperature; The pressure sensor module (36) includes a plurality of pressure sensors, which are respectively used to monitor the pumping pressure of the second water pump (12) and the third water pump (17) and the pressure drop loss of the heat exchange fluid after flowing through the active magnetic regenerator (2); The flow sensor module (37) includes a first flow sensor, a second flow sensor, and a third flow sensor, which are respectively used to monitor the heat exchange flow of the hot flow, the cold flow, and the heat exchange flow of the heat exchange fluid on the constant temperature water bath (10); The liquid level sensor module (38) comprises a first liquid level sensor and a second liquid level sensor, which are used to monitor the liquid level changes of the first water tank (11) and the second water tank (18) respectively; The metal proximity switch sensor module (4) comprises a first metal proximity switch sensor (32) for realizing high magnetic field positioning and a second metal proximity switch sensor (33) for realizing low magnetic field positioning. Before the system is operated, the high field and low field positions of the magnetic field are calibrated by the magnetic induction proximity switch sensor (31). When the system is operated, the metal proximity switch sensor module (4) can provide a signal indicating that the magnetization / demagnetization position is in place during the cycle. The magnetic induction proximity switch sensor (31) is used to achieve initial calibration of high / low magnetic field positions; The servo encoder (27) is connected to the servo motor (26) and the servo driver (39) and is used to convert mechanical signals into electrical signals, thereby realizing feedback of the position and speed information of the servo motor (26) to the control system and ensuring the operating accuracy of the servo motor (26).

3. A room temperature magnetic heat pump control system according to claim 1, characterized in that: The actuator module (15) comprises a servo motor (26), a first water pump (9), a second water pump (12), a third water pump (17), a PTC heating plate (20), a first solenoid valve (7), a second solenoid valve (21), a servo driver (39), a photoelectric coupler (40), a water pump driver (41), a PTC driver (42), and a relay (43); The servo motor (26) is connected to the Halbach inner magnet (28) via a driving gear (25), a toothed belt (24), and a driven gear (23) to control the periodic rotation of the Halbach inner magnet (28). Each time the Halbach inner magnet (28) rotates 180°, a magnetization or demagnetization process of the system is realized. The first water pump (9), the second water pump (12), and the third water pump (17) are connected to the water pump driver (41), the first water pump (9) is used to drive the heat exchange between the heat exchange fluid and the cold flow fluid on the constant temperature water bath (10), and the second water pump (12) and the third water pump (17) are used to drive the circulation of the hot flow fluid and the cold flow fluid, respectively controlling the hot flow time / flow rate of the heat transfer fluid after demagnetization and the cold flow time / flow rate of the heat transfer fluid after magnetization; The PTC heating sheet (20) is attached to the surface of the second heat exchanger (19) and is used to provide an external heat load to the cold end of the room temperature magnetic heat pump system, thereby realizing the measurement of cooling capacity using a thermal compensation method; The first solenoid valve (7) and the second solenoid valve (21) are connected to the relay (43) and are used to control the on / off of the cold flow path and the hot flow path respectively, so as to ensure the correct timing of the cold / hot flow; The servo driver (39) is connected to the photoelectric coupler (40), the servo motor (26), the servo encoder (27), and the single-chip microcomputer (14), and is used to receive a pulse control signal sent by the single-chip microcomputer (14) to the photoelectric coupler (40) and drive the servo motor (26), thereby realizing primary transmission of the feedback signal of the servo encoder (27) to the servo driver, and secondary transmission of the feedback signal via the servo driver (39) to the single-chip microcomputer (14); The photoelectric coupler (40) is connected to the single chip microcomputer (14) and the servo driver (27) to realize drive signal amplification and photoelectric isolation protection; The water pump driver (41) is connected to the single-chip computer (14) and the water pump (9, 12, 17) and is used to convert the control signal of the single-chip computer (14) into an effective voltage at both ends of the water pump (9, 12, 17), thereby realizing intermittent start and stop control and dynamic speed regulation control of the water pump (9, 12, 17); The PTC driver (42) is connected to the single-chip computer (14) and the PTC heating plate (20) and is used to convert the control signal of the single-chip computer (14) into an effective voltage across the PTC heating plate (20) to achieve different heating powers; The relay (43) is connected to the single-chip computer (14) and the electromagnetic valve (7, 21) and is used to realize the on-off control of the electromagnetic valve (7, 21) by the high and low level control signals of the single-chip computer (14).

4. A control method for realizing the room temperature magnetic heat pump control system according to any one of claims 1 to 3, characterized in that: Including timing matching control, PWM speed control, signal acquisition control, liquid level self-balancing control, magnetic field positioning control, and variable load dynamic control.

5. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: The timing matching control method includes the following two operating modes: Operation mode 1: A continuous operation mode based on the reverse Brayton heat recovery cycle, wherein the servo motor (26) operates continuously, and the third water pump (17), the first solenoid valve (7), the second water pump (12), and the second solenoid valve (21) operate intermittently; when the servo motor (26) drives the Halbach internal magnet (28) to rotate to a position near the highest magnetic field, the third water pump (17) and the first solenoid valve (7) are opened to perform a cold flow process; when the servo motor (26) rotates to a position near the lowest magnetic field, the second water pump (12) and the second solenoid valve (21) are opened to perform a hot flow process; when the servo motor (26) is near a position other than the highest / lowest magnetic field, all water pumps and solenoid valves are closed; The single-cycle timing sequence is as follows: the servo motor (26) rotates continuously, and the third water pump (17) and the first solenoid valve (7) are turned on at a position 30° before the Halbach inner magnet (28) reaches the highest magnetic field position; the third water pump (17) is turned off after the Halbach inner magnet (28) rotates 30° past the highest magnetic field position, and the first solenoid valve (7) is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the cold flow process; the second water pump (12) and the second solenoid valve (21) are turned on at a position 30° before the Halbach inner magnet (28) reaches the lowest magnetic field position; the second water pump (12) is turned off after the Halbach inner magnet (28) rotates 30° past the lowest magnetic field position, and the second solenoid valve (21) is closed with a delay of m seconds to balance the pressure wave inside the pipeline and complete the hot flow process; Operation mode 2: intermittent operation mode based on the reverse Brayton regenerative cycle, the servo motor (26) operates intermittently, the third water pump (17), the first solenoid valve (7), the second water pump (12), and the second solenoid valve (21) operate intermittently, and the servo motor (26) and the third water pump (17) and the second water pump (12) do not operate at the same time; The single cycle timing is as follows: the servo motor (26) rotates to drive the Halbach internal magnet (28) to rotate 180° from the lowest magnetic field position to the highest magnetic field position and then stops, so that the magnetic flux density in the middle pore area (30) changes from 0 to the maximum value, completing a magnetization process of the magnetocaloric material; at the moment the servo motor (26) stops, the third water pump (17) and the first solenoid valve (7) are turned on, and the cold flow process is carried out in a fully magnetized state. After the second flow sensor detects that the heat exchange fluid flow rate reaches a predetermined value, the third water pump (17) is turned off, and the first solenoid valve (7) is closed with a delay of m seconds to balance the pressure wave inside the pipeline; at the moment the third water pump (17) is turned off, the servo motor (26) is turned on again. The device is started, rotated to drive the Halbach inner magnet (28) to rotate 180° from the highest magnetic field to the lowest magnetic field and then stops, so that the magnetic flux density in the middle pore area (30) decreases from the maximum value to 0, completing a demagnetization process of the magnetocaloric material; the second water pump (12) and the second solenoid valve (21) are turned on at the moment the servo motor (26) stops, and the heat flow process is carried out in a completely demagnetized state. After the first flow sensor detects that the heat exchange fluid flow reaches a predetermined value, the second water pump (12) is turned off, and the second solenoid valve (21) is closed with a delay of m seconds to balance the pressure wave inside the pipeline; at the moment the second water pump (12) is turned off, the servo motor (26) is started again to carry out the next cycle of the magnetization process.

6. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: The PWM speed control includes frequency modulation control of the servo motor (26) and PWM control of the water pump (9, 12, 17); During the frequency modulation control of the servo motor (26), the duty cycle of the pulse sent by the single chip microcomputer (14) is kept unchanged, and the pulse frequency is changed to change the rotation speed of the servo motor (26). Specifically, the pulse frequency is adjusted through the progress bar of the serial port screen (16) to realize the frequency modulation control of the servo motor (26); During the PWM control of the water pump (9, 12, 17), the pulse frequency sent by the single chip microcomputer (14) is kept unchanged, and the pulse duty ratio is changed to change the rotation speed of the water pump (9, 12, 17). Specifically, the pulse duty ratio is adjusted through the progress bar of the serial port screen (16) to realize the PWM control of the water pump (9, 12, 17).

7. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: The signal acquisition control comprises a temperature sensor module (35), a pressure sensor module (36), a flow sensor module (37), a liquid level sensor module (38), a metal proximity switch sensor module (4), a magnetic induction proximity switch sensor (31), and a servo encoder (27) signal acquisition control; During the control process of the temperature sensor module (35) and the liquid level sensor module (38), the temperature signal and the liquid level signal are input through the A / D conversion module of the single chip computer (14), and the analog signal data is converted into digital signal data, thereby obtaining the actual temperature value and the liquid level height value; During the control process of the pressure sensor module (36), the current signal output by the pressure sensor module (36) is converted into a voltage signal by the current-to-voltage module, and then input into the single-chip microcomputer A / D conversion module to convert the analog signal data into digital signal data, thereby obtaining the actual pressure value; During the control process of the flow sensor module (37), the flow sensor module (37) uses the timer module input capture function of the single chip microcomputer (14), and uses two timers, one for timing n seconds and the other for capturing external input pulses, so that the frequency of the external input pulses can be calculated from the number of pulses captured within n seconds, and then the actual flow value can be obtained by conversion; During the control process of the metal proximity switch sensor module (4), when the metal proximity switch sensor module (4) is in the high / low magnetic field position, a level jump will occur, generating a switch signal, which is input into the GPIO port of the single-chip computer and read, and controls the timing of the cold / hot flow process in the cycle program; The magnetic induction proximity switch sensor (31) will experience a level jump when the high / low magnetic field position is in place, generating a switch signal, and the switch signal is input into the GPIO port of the single-chip computer to be read to calibrate the initial magnetic field position; The servo encoder (27) counts the actual output pulse number of the servo motor (26), transmits it to the servo driver (39) and the single-chip microcomputer (14), and compares it with the input pulse number sent by the single-chip microcomputer (14) to the servo motor (26), so as to realize feedback and correction of the motion signal.

8. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: The liquid level self-balancing control is achieved by collecting the return value of the liquid level sensor module (38), calculating the absolute value of the difference between the rising values ​​of the corresponding water tank liquid level height position in the cold / hot flow process, and changing the size of the corresponding water pump duty cycle to achieve self-balancing of the water tank liquid level.

9. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: In the magnetic field positioning control process, the position of the metal proximity switch sensor module (4) is determined by the position opposite to the magnetic field positioning mark (3) in a high magnetic field and the position opposite to the magnetic field positioning mark (3) in a low magnetic field; the first metal proximity switch sensor (32) is opposite to the magnetic field positioning mark (3) in a high magnetic field, and the second metal proximity switch sensor (33) is opposite to the magnetic field positioning mark (3) in a low magnetic field; When the room temperature magnetic heat pump regenerative cycle is performed, when the Halbach internal magnet (28) rotates to perform magnetization or demagnetization, whenever the magnetic field positioning mark (3) rotates to a position directly facing the first metal proximity switch sensor (32), it is proved that this position is a high magnetic field position, and at this time, the first metal proximity switch sensor (32) sends a high magnetic field position arrival signal to the single chip microcomputer (14); whenever the magnetic field positioning mark (3) rotates to a position directly facing the second metal proximity switch sensor (33), it is proved that this position is a low magnetic field position, and at this time, the second metal proximity switch sensor (33) sends a low magnetic field position arrival signal to the single chip microcomputer (14); In the continuous operation mode, after the metal proximity switch sensor module (4) sends a high / low magnetic field position arrival signal to the single chip microcomputer (14), the magnetization / demagnetization and cold / hot flow timing sequence are calibrated by calculating whether the moment of reaching the position is the middle moment of the flow; In the intermittent operation mode, after the metal proximity switch sensor module (4) sends a high / low magnetic field position arrival signal to the single chip microcomputer (14), the servo motor (26) duty cycle reset instruction is executed, the servo motor (26) stops rotating, and the cold / hot flow process is carried out.

10. The control method of the room temperature magnetic heat pump control system according to claim 4, characterized in that: The variable load dynamic control includes variable cooling load dynamic control and variable heating load dynamic control; The variable cooling load in the variable cooling load dynamic control is achieved by changing the temperature of the constant temperature water bath (10) at the hot end and changing the flow rate of the heat exchange fluid on this side by controlling the voltage of the first water pump (9), so as to realize different cooling load simulations; the variable cooling load dynamic control is to compare the temperature span at this time with the set temperature span, input the fuzzy PID controller, perform calculations through the fuzzy PID control algorithm, and change the heat flow and cold flow circulation flow rates by controlling the voltage of the second water pump (12) and the third water pump (17), so as to control the room temperature magnetic heat pump system to maintain the set temperature span under the current cooling load, so as to realize the variable cooling load dynamic control; The variable heat load in the variable heat load dynamic control is to achieve different heat load simulations by changing the voltage of the PTC heating plate (20) at the cold end; the variable heat load dynamic control is to compare the temperature span at this time with the set temperature span, input it into the fuzzy PID controller, and perform calculations through the fuzzy PID control algorithm. By controlling the voltage of the second water pump (12) and the third water pump (17), the heat flow and cold flow circulation flow rates are changed, and the room temperature magnetic heat pump system is controlled to maintain the set temperature span under the current heat load, so as to achieve the variable heat load dynamic control.

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