Starting protection circuit and starting cabinet for air conditioning unit

Abstract

The present application relates to a starting protection circuit and a starting cabinet for an air-conditioning unit, including a starting control circuit, a working control circuit and a delay control circuit. The starting control circuit includes a starting device, a start-stop excitation device and a normally closed start-stop switch device connected in series; the working control circuit includes a working control circuit, the start-stop excitation device is used to control the working control circuit, and the working control circuit is used to start or stop the working load; the delay control circuit includes a delay excitation device, the start-stop excitation device is used to control the delay excitation device, and the delay excitation device is used to control the start-stop switch device. The starting protection circuit provided by the present application sets the shortest shutdown time for restarting the compressor after stopping by connecting the delay control circuit in parallel next to the starting control circuit through the interval delay relay and its controllable delay contact, thereby avoiding damage to the compressor caused by restarting in a short time due to a control center failure.

Description

Technical Field

[0001] The present application relates to a control device, and more particularly to a start-up protection circuit and a start-up cabinet for a compressor of an air-conditioning unit. Background Art

[0002] During the use of the air-conditioning unit, starting and stopping the compressor is a common operation. A control system for starting / stopping the compressor is provided in the starter cabinet of the air-conditioning unit, which usually includes a control center and a starter. During the use of the air-conditioning unit, a start / stop signal can be sent to the starter through the control center by manual operation or automatic control. After receiving the start / stop signal, the starter starts or stops the compressor through the corresponding control circuit. Summary of the invention

[0003] In the air-conditioning system, after the compressor stops, it needs to remain in the stopped state for a period of time to ensure that the compressor is completely stopped and lubricated before the next start. Therefore, in the control circuit of the air-conditioning unit start cabinet, the control center will set a certain downtime, and the start signal will not be issued until the compressor stops for a period of time. However, after observation and analysis, the inventor found that: when some components of the control center fail, such as the jitter of the relay contacts, the start signal will be issued again in a short time, which will cause the compressor to start again when it has not completely stopped or the downtime is insufficient, which is easy to cause serious damage to the compressor. The usual fault protection circuit is also difficult to detect such faults in the control center. Therefore, the inventor found that when the control center fails, it may be difficult to guarantee the necessary downtime of the compressor. Although it is easier to guarantee the downtime of the compressor by writing a program, the implementation cost is high and the reliability is poor.

[0004] The startup protection circuit provided by the present application sets the shortest delay time for restarting the compressor after stopping by connecting a delay control circuit in parallel to the startup control circuit, through an interval delay relay and its controllable delay contact, thereby avoiding the situation where the compressor restarts within the shortest delay time. In addition, the startup protection circuit provided by the present application cooperates with the control center to realize the automatic startup of the compressor.

[0005] On the one hand, the present application provides a start-up protection circuit, comprising: a start-up control circuit, a working control circuit and a delay control circuit; the start-up control circuit comprises a start-up device, a start-stop excitation device and a start-stop switch device, wherein the start-up device, the start-stop excitation device and the start-stop switch device are connected in series to form a series path, and the start-stop switch device is normally closed; the working control circuit comprises a working control circuit, wherein the start-stop excitation device is used to control the working control circuit, and the working control circuit is used to start or stop the working load; the delay control circuit comprises a delay excitation device, wherein the start-stop excitation device is used to control the delay excitation device, and the delay excitation device is used to control the start-stop switch device.

[0006] According to the above-mentioned starting protection circuit, after receiving the starting signal, the starting device connects the starting control loop to stimulate the start-stop stimulation device.

[0007] According to the above startup protection circuit, the startup control loop, the working control loop and the delay control loop are connected in parallel to form a parallel path, and the parallel path has two connection ends, which are respectively connected to the two poles of the control power supply.

[0008] According to the above-mentioned starting protection circuit, the starting protection circuit includes a first relay, the first relay includes a first excitation coil, a first normally open contact and a second normally closed contact, wherein the start-stop excitation device is the first excitation coil of the first relay; the working control circuit includes a closing circuit and an opening circuit connected in parallel; the closing circuit includes a closing coil connected in series and a first normally open contact of the first relay, and the closing coil starts the workload when it is energized; the opening circuit includes an opening coil connected in series and a second normally closed contact of the first relay, and the opening coil stops the workload when it is energized; wherein, when the first excitation coil of the first relay is energized, the first normally open contact of the first relay is connected to energize the closing coil, and the second normally closed contact of the first relay is disconnected to de-energize the opening coil.

[0009] According to the above-mentioned starting protection circuit, the starting protection circuit includes a first relay, the first relay includes a first excitation coil and a third normally closed contact, wherein the start-stop excitation device is the first excitation coil of the first relay; the delay control circuit also includes the third normally closed contact of the first relay connected in series with the delay excitation device; wherein the third normally closed contact of the first relay is connected when the first excitation coil of the first relay is de-energized, and the third normally closed contact of the first relay is disconnected when the first excitation coil of the first relay is energized.

[0010] According to the above-mentioned starting protection circuit, the starting protection circuit includes a first interval delay relay, and the first interval delay relay includes a third excitation coil and a normally closed delay contact, wherein the delay excitation device is the third excitation coil of the first interval delay relay, and the start-stop switch device is the normally closed delay contact of the first interval delay relay; wherein, when the third excitation coil of the first interval delay relay is energized, the normally closed delay contact of the first interval delay relay is immediately disconnected, and the normally closed delay contact of the first interval delay relay is connected after a predetermined time.

[0011] According to the above-mentioned starting protection circuit, the starting protection circuit includes a second interval delay relay and a second relay, wherein the second interval delay relay includes a fourth excitation coil and a normally open delay contact, and the second relay includes a second excitation coil and a fourth normally closed contact; the start-stop switch device is the fourth normally closed contact of the second relay; the delay excitation device includes the fourth excitation coil of the second interval delay relay, the normally open delay contact of the second interval delay relay and the second excitation coil of the second relay, wherein the second excitation coil of the second relay and the normally open delay contact of the second interval delay relay are connected in series and then connected in parallel with the fourth excitation coil of the second interval delay relay; wherein, when the fourth excitation coil of the second interval delay relay is energized, the normally open delay contact of the second interval delay relay is immediately connected to enable the second excitation coil of the second relay to be energized, and after a predetermined time, the normally open delay contact of the second interval delay relay is disconnected to enable the second excitation coil of the second relay to be de-energized; and when the second excitation coil of the second relay is energized, the fourth normally closed contact of the second relay is disconnected, and when the second excitation coil of the second relay is de-energized, the fourth normally closed contact of the second relay is connected.

[0012] According to the above-mentioned starting protection circuit, the duration that the start-stop switch device is in the off state is set to the shortest shutdown duration of the workload.

[0013] According to the above startup protection circuit, the workload is a compressor.

[0014] On the other hand, the present application also provides a starting cabinet for an air-conditioning unit, comprising: a control center for sending a starting signal; and the above-mentioned compressor starting protection circuit, wherein a starting device is used to receive the starting signal.

[0015] According to the above-mentioned starter cabinet, it also includes: a fault protection device for controlling the working control circuit to stop the compressor of the air-conditioning unit when a fault occurs during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The startup protection circuit of the present application will become more easily understood when the following detailed description is read in conjunction with the accompanying drawings, in which the same reference numerals represent the same elements throughout the drawings.

[0017] Figure 1 It is a schematic diagram of the startup protection circuit in this application.

[0018] Figure 2A ‐2B is a schematic diagram of the first relay and the second relay in this application.

[0019] Figure 2C ‐2D is a schematic diagram of the first interval delay relay and the second interval delay relay in the present application.

[0020] Figure 3A ‐3C is Figure 1 Schematic diagram of different embodiments of the startup protection circuit. DETAILED DESCRIPTION

[0021] Various specific embodiments of the present application will be described below with reference to the accompanying drawings which constitute a part of this specification. In the following drawings, the same elements use the same figure numbers, and similar elements use similar figure numbers to avoid repeated description.

[0022] Figure 1 FIG. 1 shows a schematic structure of an embodiment of a startup protection circuit 100 in the present application. Figure 1 As shown, the startup protection circuit 100 in the present application includes a startup control loop 110, a working control loop 120 and a delay control loop 130. The startup control loop 110, the working control loop 120 and the delay control loop 130 are connected in parallel to form a parallel path with three branches, and the parallel path has two connection terminals 101 and 102, which are respectively connected to the two poles (positive pole and negative pole) of the control power supply.

[0023] The start control circuit 110 includes a start device 111, a start-stop excitation device 112 and a start-stop switch device 113. The start device 111, the start-stop excitation device 112 and the start-stop switch device 113 are connected in series to form a series path, wherein the start-stop switch device 113 is normally closed. Figure 1 The middle start-stop switch device 113 can be connected in series between the starting device 111 and the start-stop excitation device 112, but the start-stop switch device 113 can also be arranged in front of the starting device 111 in the series path or behind the start-stop excitation device 112 in the series path.

[0024] The starting device 111 receives a start or stop signal from the control center 103, and accordingly connects or disconnects the part of the starting control loop 110 at the starting device 111. The starting device 111 includes a corresponding signal receiving device and a switch device, which can be implemented in a variety of different ways. In one embodiment, the control center 103 can send different start or stop signals to the starting device 111 (such as a high level indicates a start signal, and a low level indicates a stop signal). The starting device 111 connects the starting control loop 110 when it receives the start signal, and disconnects the starting control loop 110 when it receives the stop signal. In another embodiment, the control center 103 can continuously send or stop sending a certain signal to the starting device as a start or stop signal (such as continuously sending a certain level indicates a start signal, and stopping sending the level indicates a stop signal). The starting device 111 connects the starting control loop 110 when it receives the signal, and disconnects the starting control loop 110 when it does not receive the signal.

[0025] The working control loop 120 includes a working control circuit 121. The working control circuit 121 is used to control the working state of the working load 105, such as connecting or disconnecting the working load 105 with the working power supply to start or stop the working load 105. The start-stop excitation device 112 controls the start-stop working state of the working load 105 by controlling the working control circuit 121. In the air conditioning unit, the main working load 105 is the compressor 105.

[0026] The delay control loop 130 includes a delay excitation device 131. The delay excitation device 131 is used to control the disconnection and delayed connection of the start-stop switch device 113, thereby controlling the disconnection and delayed connection of the start control loop 110.

[0027] The following describes the working process of the startup protection circuit 100 of the present application by taking the compressor 105 of the air-conditioning unit as the working load 105. It is understandable that the working load 105 may also be other types of electrical equipment.

[0028] The control center 103 in the start cabinet of the air conditioning unit can manually or automatically send a start signal to the start device 111. Before the control center 103 sends a start signal, the start-stop switch device 113 is connected (i.e., normally closed), and the start device 111 disconnects the start control loop 110.

[0029] When the control center 103 sends a start signal, the start device 111 receives the start signal and connects to the start control circuit 110, thereby connecting the excitation current in the series path to excite the start-stop excitation device 112. Then, the start-stop excitation device 112 manipulates the corresponding switch contacts in the working control circuit 121 ( Figure 1 Not shown, see Figure 3A‐3C) to start the compressor 105.

[0030] When the control center 103 sends a stop signal (or stops sending a start signal), the start device 111 disconnects the start control circuit 110, and the excitation current disappears at the start-stop excitation device 112. Then, due to the disappearance of the excitation current, the start-stop excitation device 112 manipulates the corresponding switch contacts in the working control circuit 121 ( Figure 1 Not shown, see Figure 3A -3C) to stop the compressor 105. In addition, the start-stop excitation device 112 simultaneously sends a control signal (or electromagnetic control signal) to the delay excitation device 131, so that the delay excitation device 131 is immediately disconnected and starts to delay control the start-stop switch device 113, so that within a predetermined time period (for example, within 20 seconds), even if the start device 111 receives a start signal, the start control circuit 110 will not be connected, because the start-stop switch device 113 is in a disconnected state; after exceeding the predetermined time period, the delay excitation device 131 connects the start-stop switch device 113, and if the start device 111 receives a start signal again at this time, the start control circuit 110 can be connected.

[0031] When the start-stop switch device 113 is in the disconnected state, the start control circuit 110 is also in the disconnected state. During this period, even if the control center 103 sends a start signal again, the start control circuit 110 cannot generate an excitation current to excite the start-stop excitation device 112, so that the compressor 105 cannot be started. In this way, the compressor 105 will not be started again when it has not been completely shut down or the shutdown time is insufficient. The duration of the start-stop switch device 113 being in the disconnected state can be pre-set as needed, for example, the duration of the start-stop switch device 113 being in the disconnected state is set to the shortest shutdown time or safe shutdown time (such as 20 seconds) required for the compressor 105 to start again. After the set time interval, the start-stop switch device 113 is turned on, and the start control circuit 110 returns to the initial connected state. At this time, the control center 103 can start the compressor 105 normally when it sends a start signal again.

[0032] The startup protection circuit 100 of the present application can also realize the automatic startup of the compressor 105 by cooperating with the control center 103. The time interval when the start-stop switch device 113 is in the off state is set as the time interval for the automatic startup of the compressor 105 after shutdown, and the control center 103 is set to send a startup signal or continuously send a startup signal when the start-stop switch device 113 is turned on, so that the compressor 105 can be automatically started after the set time interval.

[0033] In addition, the starter cabinet also includes a fault protection device 104 for controlling the working control circuit 121. When the compressor 105 fails during operation, the fault protection device 104 can detect the occurrence of the fault and send a fault signal to the working control circuit 121, manipulating the corresponding switch contacts in the working control circuit 121 ( Figure 1 Not shown, see Figure 3A ‐3C) to stop the compressor.

[0034] Figure 2A 2B shows the schematic structure of the first relay 310 and the second relay 320 in the present application. The first relay 310 and the second relay 320 can both adopt common electromagnetic relays, such as 3TH8244 model. The first relay 310 and the second relay 320 respectively include an excitation coil and at least one controllable contact, and the on-off state of the controllable contact is switched by energizing and de-energizing the excitation coil. The initial state of the controllable contact can be set to normally open or normally closed as needed.

[0035] exist Figure 2A In the embodiment of the present invention, the first relay 310 has a first excitation coil 210 and three controllable contacts 211, 212, 213, wherein the first normally open contact 211 is normally open, and the second normally closed contact 212 and the third normally closed contact 213 are normally closed. When the first excitation coil 210 is energized, the first normally open contact 211 is connected, and the second normally closed contact 212 and the third normally closed contact are disconnected; when the first excitation coil 210 is de-energized, the first normally open contact 211 is disconnected, and the second normally closed contact 212 and the third normally closed contact are connected.

[0036] exist Figure 2B In the embodiment of the present invention, the second relay 320 has a second excitation coil 220 and a controllable contact 221, wherein the fourth normally closed contact 221 is normally closed. When the second excitation coil 220 is energized, the fourth normally closed contact 221 is disconnected; when the second excitation coil 220 is de-energized, the fourth normally closed contact 221 is connected.

[0037] Figure 2C‐2D shows the schematic structure of the first interval delay relay 330 and the second interval delay relay 340 in the present application. A time relay is a relay that can close or open contacts before, during or after a set timing period, and is a device for time management. The first interval delay relay 330 and the second interval delay relay 340 in the present application are a type of time relay, such as the ST3PGB model. The first interval delay relay 330 and the second interval delay relay 340 respectively include an excitation coil and at least one controllable delay contact, which immediately switches the on-off state of the controllable delay contact when the excitation coil is energized, and restores the on-off state of the controllable delay contact to the initial state after a predetermined time. The initial state of the controllable delay contact can be set to normally open or normally closed as needed.

[0038] exist Figure 2C In the embodiment of the invention, the first interval delay relay 330 has a third excitation coil 230 and a controllable delay contact 231, wherein the normally closed delay contact 231 is normally closed. When the third excitation coil 230 is energized, the normally closed delay contact 231 is immediately disconnected, and the normally closed delay contact 231 is connected after a predetermined time; when the third excitation coil 230 is energized and then loses power after a predetermined time, the normally closed delay contact 231 remains connected.

[0039] exist Figure 2D In the embodiment of the invention, the second interval delay relay 340 has a fourth excitation coil 240 and a controllable delay contact 242, wherein the normally open delay contact 242 is normally open. When the fourth excitation coil 240 is energized, the normally open delay contact 242 is immediately connected, and the normally open delay contact 242 is disconnected after a predetermined time; when the fourth excitation coil 240 loses power after a predetermined time after being energized, the normally open delay contact 242 remains disconnected.

[0040] Figure 3A Shows Figure 1 The schematic structure of the first embodiment of the startup protection circuit 100 is used to illustrate more specific details of the startup protection circuit 100. Figure 2A As shown, the startup protection circuit 100 includes a first relay 310 (see Figure 2A ). The first relay 310 further includes a first excitation coil 210, a first normally open contact 211, a second normally closed contact 212 and a third normally closed contact 213, wherein the first excitation coil 210 of the first relay 310 is used as Figure 1 The implementation of the start-stop activation device 112 is shown in FIG.

[0041] exist Figure 3AIn the embodiment, the working control circuit 121 includes a closing circuit 122 and an opening circuit 123 connected in parallel. The closing circuit 122 includes a closing coil 201 and a first normally open contact 211 of a first relay 310 connected in series, and the compressor 105 is started when the closing coil 201 is energized. The opening circuit 123 includes an opening coil 202 and a second normally closed contact 212 of the first relay 310 connected in series, and the compressor 105 is stopped when the opening coil 202 is energized. When the first excitation coil 210 of the first relay 310 is energized, the first normally open contact 211 of the first relay 310 is connected to energize the closing coil 201, and the second normally closed contact 212 of the first relay 310 is disconnected to de-energize the opening coil 202, thereby starting the compressor 105.

[0042] The delay control circuit 130 includes a delay excitation device 131 and a third normally closed contact 213 of the first relay 310 connected in series. When the start device 111 disconnects the start control circuit 110 according to the stop signal, the first excitation coil 210 of the first relay 310 loses power, and then the third normally closed contact 213 of the first relay 310 is connected to connect the delay control circuit 130, thereby exciting the delay excitation device 131, so that the delay excitation device 131 immediately disconnects the start-stop switch device 113, and then connects the start-stop switch device 113 after a period of time. When the start device 111 connects the start control circuit 110 according to the start signal, the first excitation coil 210 of the first relay 310 is energized, and then the third normally closed contact 213 of the first relay 310 is disconnected to disconnect the delay control circuit 130. At this time, since the start-stop switch device 113 is already in the on state, the delay excitation device 131 does not operate the start-stop switch device 113.

[0043] Figure 3B Shows Figure 1 The schematic structure of the second embodiment of the startup protection circuit 100 is used to illustrate more specific details of the startup protection circuit 100. Figure 3B As shown, the start protection circuit 100 includes a first interval delay relay 330 (see Figure 2C ). The first interval delay relay 330 further includes a third excitation coil 230 and a normally closed delay contact 231. Figure 3A Compared with the embodiment, the third excitation coil 230 of the first interval delay relay 330 is used as an implementation of the delay excitation device 131, and the normally closed delay contact 231 of the first interval delay relay 330 is used as an implementation of the start-stop switch device 113.

[0044] exist Figure 3BIn the embodiment, when the starting device 111 disconnects the starting control circuit 110 according to the stop signal, the first excitation coil 210 of the first relay 310 loses power, and then the third normally closed contact 213 of the first relay 310 is connected to connect the delay control circuit 130, so that the third excitation coil 230 of the first interval delay relay 330 is energized, thereby immediately disconnecting the normally closed delay contact 231 of the first interval delay relay 330, and connecting the normally closed delay contact 231 of the first interval delay relay 330 after a period of time. When the starting device 111 is connected to the starting control circuit 110 according to the starting signal, the first excitation coil 210 of the first relay 310 is energized, and then the third normally closed contact 213 of the first relay 310 is disconnected to disconnect the delay control circuit 130, so that the third excitation coil 230 of the first interval delay relay 330 loses power; at this time, since the third excitation coil 230 of the first interval delay relay 330 has been in the energized state before, the normally closed delay contact 231 of the first interval delay relay 330 remains in the connected state.

[0045] Figure 3C Shows Figure 1 The schematic structure of another embodiment of the startup protection circuit includes a second relay 320 (see Figure 2B ) and the second interval delay relay 340 (see Figure 2D ). The second relay 320 further includes a second excitation coil 220 and a fourth normally closed contact 221. The second interval delay relay 340 further includes a fourth excitation coil 240 and a normally open delay contact 242. The second excitation coil 220 of the second relay 320 and the normally open delay contact 242 of the second interval delay relay 340 are connected in series and then connected in parallel with the fourth excitation coil 240 of the second interval delay relay 340.

[0046] and Figure 3A Compared with the embodiment of the present invention, the second excitation coil 220 of the second relay 320, the normally open delay contact 242 of the second interval delay relay 340 and the fourth excitation coil 240 of the second interval delay relay 340 are collectively used as an implementation of the delay excitation device 131. The fourth normally closed contact 221 of the second relay 320 is used as an implementation of the start-stop switch device 113.

[0047] exist Figure 3CIn the embodiment, when the starting device 111 disconnects the starting control circuit 110 according to the stop signal, the first excitation coil 210 of the first relay 310 loses power, and then the third normally closed contact 213 of the first relay 310 is connected to connect the delay control circuit 130, so that the fourth excitation coil 240 of the second interval delay relay 340 is energized, thereby immediately connecting the normally open delay contact 242 of the second interval delay relay 340, so that the second excitation coil 220 of the second relay 320 is energized. When the second excitation coil 220 of the second relay 320 is energized, the fourth normally closed contact 221 of the second relay 320 is disconnected. After a period of time, the normally open delay contact 242 of the second interval delay relay 340 is disconnected, so that the second excitation coil 220 of the second relay 320 loses power, thereby connecting the fourth normally closed contact 221 of the second relay 320.

[0048] When the starter 111 is connected to the starter control circuit 110 according to the starter signal, the first excitation coil 210 of the first relay 310 is energized, and then the third normally closed contact 213 of the first relay 310 is disconnected to disconnect the delay control circuit 130, so that the fourth excitation coil 240 of the second interval delay relay 340 is de-energized; at this time, since the fourth excitation coil 240 of the second interval delay relay 340 has been energized before, the normally open delay contact 242 of the second interval delay relay 340 remains in the disconnected state. At this time, the second excitation coil 220 of the second relay 320 remains in the de-energized state, and the fourth normally closed contact 221 of the second relay 320 remains in the connected state.

[0049] and Figure 3B Compared with the embodiment of the present invention, since the second relay 320 can be provided with more controllable contacts than the first interval delay relay 330, Figure 3C In the embodiment, the second interval delay relay 340 controls the second relay 320 and then controls the on-off setting of the start control loop 110. One delay control loop 130 can be used to control multiple other circuits or devices at the same time.

[0050] The starting protection circuit provided in the present application makes full use of the interval delay relay and its controllable delay contacts, so that after the compressor stops, the contacts connected in series in the starting control circuit are disconnected. Before the set stop time is reached, the compressor cannot be started even if a starting signal is sent again. It has a simple structure, is easy to operate, requires little change to the original circuit, and greatly improves the safety performance of the compressor.

[0051] This specification uses examples to disclose the present application, one or more of which are illustrated in the accompanying drawings. Each example is provided for the purpose of explaining the present application, not for limiting the present application. In fact, it is obvious to those skilled in the art that various modifications and variations can be made to the present application without departing from the scope or spirit of the present application. For example, the illustrated or described features as part of one embodiment can be used together with another embodiment to obtain a further embodiment. Therefore, it is intended that the present application covers modifications and variations made within the scope of the appended claims and their equivalents.

Claims

1. A startup protection circuit (100), characterized in that include: A start control loop (110), a working control loop (120) and a delay control loop (130); The start control circuit (110) comprises a start device (111), a start-stop excitation device (112) and a start-stop switch device (113), wherein the start device (111), the start-stop excitation device (112) and the start-stop switch device are connected in series to form a series path, and the start-stop switch device (113) is normally closed; The working control loop (120) comprises a working control circuit (121), wherein the start-stop excitation device (112) is used to control the working control circuit (121), and the working control circuit (121) is used to start or stop the working load (105); The delay control loop (130) comprises a delay excitation device (131), wherein the start-stop excitation device (112) is used to control the delay excitation device (131), and the delay excitation device (131) is used to control the start-stop switch device (113); The start-stop excitation device (112) is configured such that, in response to stopping the workload (105), the start-stop excitation device (112) controls the delay excitation device (131) to disconnect the start-stop switch device (113) and simultaneously starts delay control of the start-stop switch device (113) to delay the connection of the start-stop switch device (113), thereby delaying the start-stop switch device (113) and starting the workload (105).

2. The startup protection circuit (100) according to claim 1, characterized in that: After receiving the start signal, the start device (111) connects the start control loop (110) to stimulate the start-stop stimulation device (112).

3. The startup protection circuit (100) according to claim 1, characterized in that: The start control loop (110), the working control loop (120) and the delay control loop (130) are connected in parallel to form a parallel path, and the parallel path has two connection ends (101, 102) respectively connected to two poles of a control power supply.

4. The startup protection circuit (100) according to claim 3, characterized in that: The start protection circuit (100) comprises a first relay (310), the first relay (310) comprises a first excitation coil (210), a first normally open contact (211) and a second normally closed contact (212), wherein the start-stop excitation device (112) is the first excitation coil (210) of the first relay (310); The working control circuit (121) comprises a closing circuit (122) and an opening circuit (123) connected in parallel; The closing circuit (122) comprises a closing coil (201) and a first normally open contact (211) of the first relay (310) connected in series, and the working load (105) is started when the closing coil (201) is energized; The opening circuit (123) comprises an opening coil (202) and a second normally closed contact (212) of the first relay (310) connected in series, and the working load (105) is stopped when the opening coil (202) is energized; When the first excitation coil (210) of the first relay (310) is energized, the first normally open contact (211) of the first relay (310) is connected to energize the closing coil (201), and the second normally closed contact (212) of the first relay (310) is disconnected to de-energize the opening coil (202).

5. The startup protection circuit (100) according to claim 3, characterized in that: The start protection circuit (100) comprises a first relay (310), the first relay (310) comprises a first excitation coil (210) and a third normally closed contact (213), wherein the start-stop excitation device (112) is the first excitation coil (210) of the first relay (310); The delay control loop (130) further comprises a third normally closed contact (213) of the first relay (310) connected in series with the delay excitation device (131); When the first excitation coil (210) of the first relay (310) loses power, the third normally closed contact (213) of the first relay (310) is connected, and when the first excitation coil (210) of the first relay (310) is energized, the third normally closed contact (213) of the first relay (310) is disconnected.

6. The startup protection circuit (100) according to claim 5, characterized in that: The starting protection circuit (100) comprises a first interval delay relay (330), the first interval delay relay (330) comprises a third excitation coil (230) and a normally closed delay contact (231), wherein the delay excitation device (131) is the third excitation coil (230) of the first interval delay relay (330), and the start-stop switch device (113) is the normally closed delay contact (231) of the first interval delay relay (330); When the third excitation coil (230) of the first interval delay relay (330) is energized, the normally closed delay contact (231) of the first interval delay relay (330) is immediately disconnected, and after a predetermined time, the normally closed delay contact (231) of the first interval delay relay (330) is connected.

7. The startup protection circuit (100) according to claim 5, characterized in that: The startup protection circuit (100) comprises a second interval delay relay (340) and a second relay (320), wherein the second interval delay relay (340) comprises a fourth excitation coil (240) and a normally open delay contact (242), and the second relay (320) comprises a second excitation coil (220) and a fourth normally closed contact (221); The start-stop switch device (113) is a fourth normally closed contact (221) of the second relay (320); The time-delay excitation device (131) comprises a fourth excitation coil (240) of the second interval time-delay relay (340), a normally open time-delay contact (242) of the second interval time-delay relay (340), and a second excitation coil (220) of the second relay (320), wherein the second excitation coil (220) of the second relay (320) and the normally open time-delay contact (242) of the second interval time-delay relay (340) are connected in series and then connected in parallel with the fourth excitation coil (240) of the second interval time-delay relay (340); wherein, when the fourth excitation coil (240) of the second interval time delay relay (340) is energized, the normally open time delay contact (242) of the second interval time delay relay (340) is immediately connected to enable the second excitation coil (220) of the second relay (320) to be energized, and after a predetermined time, the normally open time delay contact (242) of the second interval time delay relay (340) is disconnected to enable the second excitation coil (220) of the second relay (320) to be de-energized; and When the second excitation coil (220) of the second relay (320) is energized, the fourth normally closed contact (221) of the second relay (320) is disconnected; when the second excitation coil (220) of the second relay (320) is de-energized, the fourth normally closed contact (221) of the second relay (320) is connected.

8. The startup protection circuit (100) according to claim 1, characterized in that: The duration during which the start-stop switch device (113) is in the off state is set to the shortest shutdown duration of the workload (105).

9. The startup protection circuit (100) according to any one of claims 1 to 8, characterized in that: The workload (105) is a compressor.

10. A starter cabinet for an air conditioning unit, characterized in that include: A control center (103) for sending a start signal; as well as The startup protection circuit (100) according to any one of claims 1 to 7, wherein the startup device (111) is used to receive the startup signal.

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