Magnetic regenerator module hot end constant temperature device, test system and control method

Abstract

The present invention provides a hot-end thermostat device, a test system, and a control method for a magnetic regenerator module. In the hot-end thermostat device, a forced thermostat includes an inlet and an outlet, and a valve structure includes a first end, a second end, a third end, and a fourth end. The inlet of the forced thermostat is connected to the third end of the valve structure, the outlet of the forced thermostat is connected to the inlet of a pump, the outlet of the pump is connected to the first end of the valve structure, the second end of the valve structure is used to connect to the hot end of a first magnetic regenerator module, and the fourth end of the valve structure is used to connect to the hot end of a second magnetic regenerator module. The valve structure can be controlled to switch between the following states: State 1: Within the valve structure, the first end is connected to the second end, the third end is connected to the fourth end, and the remaining port combinations are disconnected; State 2: Within the valve structure, the first end is connected to the fourth end, the second end is connected to the third end, and the remaining port combinations are disconnected; State 3: Within the valve structure, the first end is connected to the third end, and the second end is disconnected from the fourth end.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic refrigeration, and in particular to a hot end constant temperature device, a test system and a control method for a magnetic regenerator module. Background Art

[0002] This section is intended to provide a background or context to the embodiments recited in the claims. No admission is made that anything herein is prior art by virtue of its inclusion in this section.

[0003] Magnetic refrigeration is a solid-state refrigeration technology and is expected to replace traditional gas compression refrigeration technology.

[0004] Traditional magnetic refrigerators use an active magnetic regenerator with its hot end connected to a heat sink for natural or forced convection cooling. The hot end heat transfer fluid temperature cannot be kept constant, making it impossible to test the cooling capacity of the active magnetic regenerator at different temperatures, nor can it meet the requirements for testing the cooling power of the magnetic refrigerator. Summary of the Invention

[0005] The present invention provides a hot end constant temperature device, a testing system and a control method for a magnetic regenerator module.

[0006] The present invention adopts the following technical solution: a hot end thermostat for a magnetic regenerator module in a magnetic refrigerator, the magnetic refrigerator comprising a first magnetic regenerator module and a second magnetic regenerator module arranged in pairs, the hot end thermostat comprising: a forced thermostat, a pump, and a valve structure;

[0007] The forced thermostatic device includes an inlet and an outlet, and the valve structure includes a first end, a second end, a third end, and a fourth end;

[0008] The inlet of the forced thermostat is connected to the third end of the valve structure, the outlet of the forced thermostat is connected to the inlet of the pump, the outlet of the pump is connected to the first end of the valve structure, the second end of the valve structure is used to connect to the hot end of the first magnetic regenerator module, and the fourth end of the valve structure is used to connect to the hot end of the second magnetic regenerator module;

[0009] The valve structure can be controlled to switch between the following states:

[0010] State 1: inside the valve structure, the first end is connected to the second end, the third end is connected to the fourth end, and the remaining port combinations are disconnected;

[0011] State 2: inside the valve structure, the first end is connected to the fourth end, the second end is connected to the third end, and the remaining port combinations are disconnected;

[0012] State 3: inside the valve structure, the first end is connected to the third end, and the second end is disconnected from the fourth end.

[0013] In some embodiments, the valve structure includes: a first electrically controlled valve, a second electrically controlled valve, a third electrically controlled valve, and a fourth electrically controlled valve;

[0014] The first ends of the first electrically controlled valve and the third electrically controlled valve are connected to each other, and are connected to the first end of the valve structure; the second end of the first electrically controlled valve and the first end of the second electrically controlled valve are connected to each other, and are connected to the second end of the valve structure; the second end of the second electrically controlled valve and the second end of the fourth electrically controlled valve are connected to each other, and are connected to the third end of the valve structure; the second end of the third electrically controlled valve and the first end of the fourth electrically controlled valve are connected to each other, and are connected to the fourth end of the valve structure.

[0015] In some embodiments, the forced constant temperature device includes a constant temperature bath.

[0016] In some embodiments, the inlet of the forced thermostat is higher than the outlet.

[0017] The present invention adopts the following technical solution: a testing system for a magnetic refrigerator, including a magnetic refrigerator and the aforementioned hot end constant temperature device, the magnetic refrigerator including a first magnetic regenerator module and a second magnetic regenerator module arranged in pairs, the second end of the valve structure being connected to the hot end of the first magnetic regenerator module, and the fourth end of the valve structure being connected to the hot end of the second magnetic regenerator module.

[0018] In some embodiments, the test system further includes a load, two ends of which are connected to the cold ends of the first magnetic regenerator module and the second magnetic regenerator module, respectively.

[0019] In some embodiments, the testing system further comprises:

[0020] a first temperature sensor, configured to detect the temperature of the heat exchange fluid at the hot end of the first magnetic regenerator module;

[0021] a second temperature sensor, configured to detect the temperature of the heat exchange fluid at the hot end of the second magnetic regenerator module;

[0022] a third temperature sensor, configured to detect the temperature of the heat exchange fluid at the cold end of the first magnetic regenerator module;

[0023] The fourth temperature sensor is used to detect the temperature of the heat exchange fluid at the cold end of the second magnetic regenerator module.

[0024] In some embodiments, the test system further includes a fifth temperature sensor for detecting the temperature of the heat exchange fluid at the load.

[0025] The present invention adopts the following technical solution: a control method applied to the aforementioned test system, comprising a first stage, a second stage, a third stage and a fourth stage of cyclic execution:

[0026] In the first stage, the first magnetic regenerator module and the second magnetic regenerator module are in a transition state, and the valve structure is controlled to be in state 3;

[0027] In the second stage, the first magnetic regenerator module is in a cold blowing state, the second magnetic regenerator module is in a hot blowing state, and the valve structure is controlled to be in state 1;

[0028] In the third stage, the first magnetic regenerator module and the second magnetic regenerator module are in a transition state, and the valve structure is controlled to be in state 1;

[0029] In the fourth stage, the first magnetic regenerator module is in a hot blowing state, the second magnetic regenerator module is in a cold blowing state, and the valve structure is controlled to be in state 3.

[0030] In some embodiments, in the first stage, the first electrically controlled valve and the second electrically controlled valve are controlled to be turned on, and the third electrically controlled valve and the fourth electrically controlled valve are closed, or the third electrically controlled valve and the fourth electrically controlled valve are controlled to be turned on, and the first electrically controlled valve and the second electrically controlled valve are closed; in the second stage, the first electrically controlled valve and the fourth electrically controlled valve are controlled to be turned on, and the second electrically controlled valve and the third electrically controlled valve are closed; in the third stage, the first electrically controlled valve and the second electrically controlled valve are controlled to be turned on, and the third electrically controlled valve and the fourth electrically controlled valve are closed, or the third electrically controlled valve and the fourth electrically controlled valve are controlled to be turned on, and the first electrically controlled valve and the second electrically controlled valve are closed; in the fourth stage, the second electrically controlled valve and the third electrically controlled valve are controlled to be turned on, and the first electrically controlled valve and the fourth electrically controlled valve are closed.

[0031] The hot-end thermostat of the present invention ensures the normal circulation of the heat exchange fluid between the two magnetic heat exchanger modules in a magnetic refrigerator during the excitation and demagnetization phases. It also forcibly restores the hot-end heat exchange fluid temperature of the magnetic heat exchanger modules to a desired constant temperature during the transition phase of the magnetic refrigerator's operation. This ensures that the hot-end temperature of the magnetic heat exchanger modules remains constant, effectively meeting the requirements for testing the refrigeration performance of magnetic refrigerators. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 1 is a structural diagram of a magnetic refrigerator and a hot end constant temperature device thereof according to an embodiment of the present invention.

[0033] Figure 2a This is a graph showing the change of the magnetic field in the magnetic regenerator module of the magnetic refrigerator over time according to an embodiment of the present invention.

[0034] Figure 2b 3 is a working mode diagram of two magnetic regenerator modules of a magnetic refrigerator according to an embodiment of the present invention.

[0035] Figure 3 This is a graph showing changes in the hot-end heat exchange fluid temperature and the cold-end heat exchange fluid temperature over time of a magnetic regenerator module of a magnetic refrigerator according to an embodiment of the present invention.

[0036] Figure 4 The figure is a flow chart of a method for controlling a hot end constant temperature device of a magnetic refrigerator according to an embodiment of the present invention.

[0037] The figures are marked as follows: T1 to T5, the first to fifth temperature sensors; C1, the first magnetic field system; C2, the second magnetic field system; H1, the first magnetic regenerator module; H2, the second magnetic regenerator module; DF1 to DF4, the first to fourth electrically controlled valves; P, pump; HWSC, constant temperature water tank; F, load; 1, valve structure; 11 to 14, the first end to the fourth end of the valve structure. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0039] The present invention adopts a device such as a constant temperature water tank as a forced constant temperature device, and utilizes the transition period in the circulation process of the active magnetic regenerator to quickly discharge the temperature of the hot end heat exchange fluid of the active magnetic regenerator, thereby maintaining the temperature of the hot end heat exchange fluid of the active magnetic regenerator basically constant.

[0040] Figure 1 1 is a structural diagram of a magnetic refrigerator and a hot end constant temperature device thereof according to an embodiment of the present invention. Figure 2a This is a graph showing the change of the magnetic field in the magnetic regenerator module of the magnetic refrigerator over time according to an embodiment of the present invention. Figure 2b 3 is a working mode diagram of two magnetic regenerator modules of a magnetic refrigerator according to an embodiment of the present invention. Figure 3 This is a graph showing changes in the hot-end heat exchange fluid temperature and the cold-end heat exchange fluid temperature over time of a magnetic regenerator module of a magnetic refrigerator according to an embodiment of the present invention. Figure 4 The figure is a flow chart of a method for controlling a hot end constant temperature device of a magnetic refrigerator according to an embodiment of the present invention.

[0041] The heat exchange fluid in the embodiment of the present invention is water, but the present invention does not limit the selection of the heat exchange fluid.

[0042] Figure 1 , a first magnetic regenerator module H1, a second magnetic regenerator module H2, a first magnetic field system C1, a second magnetic field system C2, first to fifth temperature sensors T1 to T5, and a load F in the magnetic refrigerator are shown.

[0043] The first magnetic regenerator module H1 may include, for example, one active magnetic regenerator, or multiple active magnetic regenerators connected in parallel, or multiple active magnetic regenerators connected in series.

[0044] The second magnetic regenerator module H2 may include, for example, one active magnetic regenerator, or multiple active magnetic regenerators connected in parallel, or multiple active magnetic regenerators connected in series.

[0045] The first magnetic field system C1 and the second magnetic field system C2 are used to provide magnetic fields for the first magnetic regenerator module H1 and the second magnetic regenerator module H2 respectively.

[0046] The first temperature sensor T1 is disposed at the hot end of the first magnetic regenerator module H1 and is used to detect the temperature of the heat exchange fluid at the hot end of the first magnetic regenerator module H1.

[0047] The third temperature sensor T3 is disposed at the cold end of the first magnetic regenerator module H1 and is used to detect the temperature of the heat exchange fluid at the cold end of the first magnetic regenerator module H1.

[0048] The second temperature sensor T2 is provided at the hot end of the second magnetic regenerator module H2 and is used to detect the temperature of the heat exchange fluid at the hot end of the second magnetic regenerator module H2.

[0049] The fourth temperature sensor T4 is provided at the cold end of the second magnetic regenerator module H2 and is used to detect the temperature of the heat exchange fluid at the cold end of the second magnetic regenerator module H2.

[0050] The load F represents the cold-end heat exchanger and the actual cold-end load to which the cold-end heat exchanger is connected.

[0051] The fifth temperature sensor T5 is provided at the load F and is used to detect the temperature of the heat exchange fluid at the cold-end heat exchanger.

[0052] The following description uses a forced constant temperature device as a constant temperature water tank (HWSC) as an example. Since the heat exchange fluid is not limited to water, the constant temperature water tank (HWSC) can also be referred to as a constant temperature tank. In other embodiments, the constant temperature water tank can be replaced with a forced constant temperature heat exchange device.

[0053] refer to Figure 1 The hot end constant temperature device includes a constant temperature water tank HWSC, a pump P, and a valve structure 1.

[0054] The valve structure 1 includes: a first electrically controlled valve DF1, a second electrically controlled valve DF2, a third electrically controlled valve DF3, and a fourth electrically controlled valve DF4. The first ends of the first and third electrically controlled valves DF1 and DF3 are each connected, and are connected to a first end 11 of the valve structure 1. The second end of the first electrically controlled valve DF1 is connected to the first end of the second electrically controlled valve DF2, and is connected to a second end 12 of the valve structure 1. The second end 12 of the valve structure 1 is connected to the hot end of the first magnetic regenerator module H1. The second end of the second electrically controlled valve DF2 is connected to the second end of the fourth electrically controlled valve DF4, and is connected to a third end 13 of the valve structure 1. The second end of the third electrically controlled valve DF3 is connected to the first end of the fourth electrically controlled valve DF4, and is connected to a fourth end 14 of the valve structure 1. The fourth end 14 of the valve structure 1 is connected to the hot end of the second magnetic regenerator module H2.

[0055] The third end 13 of the valve structure 1 is connected to the inlet of the thermostatic water tank HWSC. The outlet of the thermostatic water tank HWSC is connected to the inlet of the pump P. The outlet of the pump P is connected to the first end 11 of the valve structure 1 .

[0056] Please refer to Figure 1 、 Figure 2a and Figure 2b , the four stages of the active magnetic regenerator cycle are explained.

[0057] The first stage is a transition period, during which the fluids inside the first and second magnetic regenerator modules H1 and H2 remain stationary. During this period, the first and second electrically controlled valves DF1 and DF2 are opened, allowing the hot heat exchange fluid, previously discharged from the first magnetic regenerator module H1, to rapidly flow through the constant-temperature water tank HWSC for heat exchange, maintaining a constant temperature in the piping connected to the hot end of the first magnetic regenerator module H1. Furthermore, because the piping is located close to the hot end outlet of the first magnetic regenerator module H1, the hot end of the first magnetic regenerator module H1 remains at a constant temperature.

[0058] In the first stage, the heat exchange fluid flows from the first electrically controlled valve DF1 through the second electrically controlled valve DF2 into the thermostatic water tank HWSC, and then flows from the outlet of the thermostatic water tank HWSC through the pump P into the first electrically controlled valve DF1.

[0059] In the first stage, the first magnetic regenerator module H1 is also connected to the first end 11 and the third end 13 of the valve structure 1, which helps stabilize the temperature of the first magnetic regenerator module H1. In other embodiments, in the first stage, the first magnetic regenerator module H1 is disconnected from the first end 11 and the third end 13 of the valve structure 1.

[0060] In the second phase, when the first magnetic regenerator module H1 is demagnetized (cold blow), the magnetic refrigerant in the first magnetic regenerator module H1 absorbs heat. The second magnetic regenerator module H2 is in the energized phase (hot blow). The first and fourth electrically controlled valves DF1 and DF4 are opened. The heat exchange fluid flows from the first electrically controlled valve DF1 into the first magnetic regenerator module H1, passes through the cold-end load F, flows through the second magnetic regenerator module H2, and flows through the fourth electrically controlled valve DF4 into the thermostatic water tank HWSC. From the thermostatic water tank HWSC, it flows through pump P to the first electrically controlled valve DF1.

[0061] In the second stage, the hot heat exchange fluid flowing out of the second magnetic regenerator module H2 is buffered in a constant temperature water tank and then flows back to the first heat exchanger module H1 with its temperature appropriately reduced.

[0062] The third stage is the transition period, when the heat exchange fluid inside the first magnetic regenerator module H1 and the second magnetic regenerator module H2 is stationary. At this time, the third electrically controlled valve DF3 and the fourth electrically controlled valve DF4 are opened to allow the hot heat exchange fluid discharged from the second magnetic regenerator module H2 in the previous stage to quickly flow through the constant temperature water tank HWSC for heat exchange. Figure 1 From this perspective, the heat exchange fluid flows counterclockwise between the fourth electrically controlled valve DF4, the thermostatic water tank HWSC, the pump P, and the third electrically controlled valve DF3. The heat exchange fluid in the pipeline quickly cools to the desired constant temperature.

[0063] It should be noted that in the first and third stages, it is possible to open the first and second electrically controlled valves DF1 and DF2 simultaneously or to open the third and fourth electrically controlled valves DF3 and DF4 simultaneously. This can be flexibly selected according to the actual pipeline design to maximize heat dissipation.

[0064] The valve structure 1 may be arranged close to the hot end outlets of the first magnetic regenerator module H1 and the second magnetic regenerator module H2 to keep the hot ends of the first magnetic regenerator module H1 and the second magnetic regenerator module H2 at a constant temperature.

[0065] For example, the length of the pipeline from the first magnetic regenerator module H1 to the first and second electrically controlled valves DF1 and DF2 can be set to be sufficiently short, for example, less than 10 cm. The first and second electrically controlled valves DF1 and DF2 should be as close to the hot end outlet of the first magnetic regenerator module H1 as possible to remove as much heat as possible from the hot end. The length of the pipeline from the second magnetic regenerator module H2 to the third and fourth electrically controlled valves DF3 and DF4 should be set to be sufficiently short, for example, less than 10 cm. The third and fourth electrically controlled valves DF3 and DF4 should be as close to the hot end outlet of the second magnetic regenerator module H2 as possible to remove as much heat as possible from the hot end.

[0066] During the third stage, the second magnetic regenerator module H2 is connected to the third end 13 and the first end 11 of the valve structure 1, which helps stabilize the temperature of the second magnetic regenerator module H2. In other embodiments, during the third stage, the second magnetic regenerator module H2 is disconnected from the third end 13 and the first end 11 of the valve structure 1.

[0067] In the fourth stage, the first magnetic regenerator module H1 is in the energized state (hot blowing, generating heat), and the second magnetic regenerator module H2 is in the demagnetized state (cold blowing, absorbing heat). The second and third electrically controlled valves DF2 and DF3 are open. The heat exchange fluid flows from the third electrically controlled valve DF3 into the second magnetic regenerator module H2, passes through the cold-end load F, flows through the first magnetic regenerator module H1, and flows through the second electrically controlled valve DF2 into the thermostatic water tank HWSC. From the thermostatic water tank HWSC, it flows through pump P into the third electrically controlled valve DF3, completing one cycle.

[0068] The valve structure 1 switches between the following 3 states:

[0069] State 1: inside the valve structure, the first end is connected to the second end, the third end is connected to the fourth end, and the remaining port combinations are disconnected;

[0070] State 2: inside the valve structure, the first end is connected to the fourth end, the second end is connected to the third end, and the remaining port combinations are disconnected;

[0071] State 3: inside the valve structure, the first end is connected to the third end, and the second end is disconnected from the fourth end.

[0072] In order to achieve the above technical effects, the internal structure of the valve structure 1 is not limited to Figure 1 For example, an electrically controlled valve may be provided between any two ports of the valve structure 1 .

[0073] In the above embodiments, the inlet of the constant temperature water tank HWSC is higher than the outlet thereof.

[0074] refer to Figure 1 and combined Figure 4 ,The following introduces the complete control process of the test system consisting of the ,magnetic refrigerator and its hot end constant temperature device.

[0075] Before entering this control process, it is necessary to use the positioning device and area calculation to sense the AMR cycle stage of the magnetic field system.

[0076] Specifically, the positioning device can be mechanical, photoelectric, or electromagnetic induction. It is used to determine the moment of lowest magnetic field, or zero magnetic field. The magnetic field in the magnetic refrigerator's magnetic field system varies periodically, similar to a sine wave. A cycle consists of a gradual change from a low magnetic field to a high magnetic field and then to a low magnetic field. A cycle is divided into four phases: a low magnetic field phase, a rising magnetic field phase (corresponding to a transition period), a high magnetic field phase, a falling magnetic field phase (corresponding to a transition period), and a low magnetic field phase. These four phases can be referred to as four regions in terms of time. In terms of time, if the period is fixed, as the time between the low and high magnetic fields becomes shorter, the corresponding transition period becomes longer. Conversely, as the time between the low and high magnetic fields becomes longer, the corresponding transition period becomes shorter. Once the zero magnetic field moment is determined and the positions of the four regions are defined, the control system can determine which phase is currently in.

[0077] It should be noted that, as to how to determine the specific start and end times of the four stages, those skilled in the art can implement it according to various existing methods, and the present invention does not impose any limitation thereto.

[0078] First, the transition phase begins, with the first and second electrically controlled valves DF1 and DF2 opened, and the other valves closed. Valve structure 1 is in state 3.

[0079] Subsequently, when the first magnetic regenerator module H1 is in the demagnetized state, the first and fourth electrically controlled valves DF1 and DF4 are opened, while the other valves are closed. During this phase, the second magnetic regenerator module H2 is in the energized state. Valve structure 1 is in state 1.

[0080] Then, the transition phase begins again, the third electrically controlled valve DF3 and the fourth electrically controlled valve DF4 are opened, and the other valves are closed. The valve structure 1 is in state 3.

[0081] Finally, the first magnetic regenerator module H1 is in the magnetized state, the second and third electrically controlled valves DF2 and DF3 are open, and the other valves are closed. At this stage, the second magnetic regenerator module H2 is in the demagnetized state. Valve structure 1 is in state 2.

[0082] Then proceed to the next cycle.

[0083] Figure 3 The test results of a refrigerator using the above-mentioned constant temperature device are as follows: As the operating time increases, the temperature of the heat exchange fluid at the hot end of the magnetic regenerator module remains essentially constant, meeting the test requirements of various test items for the magnetic refrigerator.

[0084] The various embodiments of the present invention are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0085] The scope of protection of the present invention is not limited to the above-described embodiments. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the scope and spirit of the present invention. If such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A control method for a magnetic refrigerator test system, characterized in that: The test system of the magnetic refrigerator includes a magnetic refrigerator and a hot end constant temperature device; The magnetic refrigerator comprises a first magnetic regenerator module and a second magnetic regenerator module arranged in pairs; The hot end constant temperature device includes: a forced constant temperature device, a pump and a valve structure; The forced thermostatic device includes an inlet and an outlet, and the valve structure includes a first end, a second end, a third end, and a fourth end; The inlet of the forced thermostat is connected to the third end of the valve structure, the outlet of the forced thermostat is connected to the inlet of the pump, the outlet of the pump is connected to the first end of the valve structure, the second end of the valve structure is connected to the hot end of the first magnetic regenerator module, and the fourth end of the valve structure is connected to the hot end of the second magnetic regenerator module; The valve structure can be controlled to switch between the following states: State 1: inside the valve structure, the first end is connected to the second end, the third end is connected to the fourth end, and the remaining port combinations are disconnected; State 2: inside the valve structure, the first end is connected to the fourth end, the second end is connected to the third end, and the remaining port combinations are disconnected; State 3: inside the valve structure, the first end is connected to the third end, and the second end is disconnected from the fourth end; The valve structure includes: a first electrically controlled valve, a second electrically controlled valve, a third electrically controlled valve and a fourth electrically controlled valve; The first ends of the first electrically controlled valve and the third electrically controlled valve are respectively in communication with each other and are in communication with the first end of the valve structure; the second end of the first electrically controlled valve is in communication with the first end of the second electrically controlled valve and are in communication with the second end of the valve structure; the second end of the second electrically controlled valve is in communication with the second end of the fourth electrically controlled valve and are in communication with the third end of the valve structure; the second end of the third electrically controlled valve is in communication with the first end of the fourth electrically controlled valve and are in communication with the fourth end of the valve structure; The first magnetic regenerator module is connected to the first electrically controlled valve and the second electrically controlled valve, and the length of the pipeline from the first magnetic regenerator module to the first electrically controlled valve and the second electrically controlled valve is less than 10 cm. The second magnetic regenerator module is connected to the third electrically controlled valve and the fourth electrically controlled valve, and the length of the pipeline from the second magnetic regenerator module to the third electrically controlled valve and the fourth electrically controlled valve is less than 10 cm. The control method includes a first stage, a second stage, a third stage and a fourth stage that are executed cyclically; In the first stage, the first electrically controlled valve and the second electrically controlled valve are controlled to be connected, and the third electrically controlled valve and the fourth electrically controlled valve are closed, or the third electrically controlled valve and the fourth electrically controlled valve are controlled to be connected, and the first electrically controlled valve and the second electrically controlled valve are closed; In the second stage, the first electrically controlled valve and the fourth electrically controlled valve are controlled to be turned on, and the second electrically controlled valve and the third electrically controlled valve are controlled to be turned off; In the third stage, the first electrically controlled valve and the second electrically controlled valve are controlled to be connected, and the third electrically controlled valve and the fourth electrically controlled valve are closed, or the third electrically controlled valve and the fourth electrically controlled valve are controlled to be connected, and the first electrically controlled valve and the second electrically controlled valve are closed; In the fourth stage, the second electrically controlled valve and the third electrically controlled valve are controlled to be connected, and the first electrically controlled valve and the fourth electrically controlled valve are controlled to be closed.

2. The control method according to claim 1, characterized in that: The forced constant temperature device includes a constant temperature bath.

3. The control method according to claim 1, wherein: The inlet of the forced thermostatic device is higher than the outlet.

4. The control method according to claim 1, wherein: The test system further includes a load, two ends of which are connected to the cold ends of the first magnetic regenerator module and the second magnetic regenerator module, respectively.

5. The control method according to claim 4, characterized in that: The test system further comprises: a first temperature sensor, configured to detect the temperature of the heat exchange fluid at the hot end of the first magnetic regenerator module; a second temperature sensor, configured to detect the temperature of the heat exchange fluid at the hot end of the second magnetic regenerator module; a third temperature sensor, configured to detect the temperature of the heat exchange fluid at the cold end of the first magnetic regenerator module; The fourth temperature sensor is used to detect the temperature of the heat exchange fluid at the cold end of the second magnetic regenerator module.

6. The control method according to claim 5, characterized in that: The test system further includes a fifth temperature sensor for detecting the temperature of the heat exchange fluid at the load.

Images