Rotating speed detection device, air conditioning system and control method of air conditioning system

Abstract

The invention relates to the technical field of air conditioners, particularly provides a rotating speed detection device, an air conditioning system and a control method of the air conditioning system, and aims to solve the problem that an existing indoor unit cannot control the accurate starting time of electric heating, and the safety problem is likely to occur. In order to achieve the purpose, the rotating speed detection device of the indoor unit comprises a rotating part, a moving part and a detection circuit, and the rotating part rotates and can periodically drive the moving part to move; the detection circuit comprises a first terminal and a second terminal which are arranged at an interval, the moving part moves periodically and fills the interval between the first terminal and the second terminal, so that the detection circuit is conducted periodically, an electric signal can be generated after conduction, and the rotating speed of the motor is determined according to the electric signal; whether the minimum rotating speed or the minimum air volume is reached or not can be determined according to the rotating speed of the motor, electric heating is started after the minimum rotating speed or the minimum air volume is reached and lasts for a certain period of time, combustible refrigerants leaked and accumulated in the indoor unit can be blown away, and it is guaranteed that no safety accident occurs when electric heating is started.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly provides a rotational speed detection device, an air conditioning system and a control method thereof. Background Art

[0002] In order to meet the requirements of environmental protection, existing air conditioners are gradually converted to use flammable refrigerants. For air conditioners using flammable refrigerants such as R32, especially those with resistive electric heating (such as PTAC through-the-wall units), there are relatively large potential safety hazards. To ensure the safety of such air conditioners during operation, UL60335 standard provides a solution idea; before the electric heating is turned on, the blower needs to maintain a minimum air volume (the minimum air volume required by the standard) for a period of time to ensure the safety after the electric heating is started.

[0003] However, the existing indoor units are unable to determine the rotational speed of the motor, resulting in an inability to accurately control the starting time of the electric heating and prone to safety problems. Summary of the Invention

[0004] The present invention aims to solve the above technical problems, that is, to solve the problem that the existing indoor units are unable to determine the rotational speed of the motor, resulting in an inability to accurately control the starting time of the electric heating and prone to safety problems.

[0005] In a first aspect, the present invention provides a rotational speed detection device, which includes:

[0006] A rotating member;

[0007] A moving member, the moving member and the rotating member are correspondingly arranged, and when the rotating member rotates, it can periodically drive the moving member to move;

[0008] A detection circuit, including a first terminal and a second terminal arranged at intervals, the moving member periodically moves and fills the interval between the first terminal and the second terminal, so that the detection circuit is periodically turned on.

[0009] In a specific embodiment of the above rotational speed detection device, the rotational speed detection device further includes a fixing member, the fixing member has an interval track, the moving member is slidably arranged on the interval track, a conductive part is arranged on the moving member, the first terminal and the second terminal are respectively connected to both sides of the interval track, and after the moving member moves, the conductive part can connect the first terminal and the second terminal to turn on the detection circuit.

[0010] In a specific embodiment of the above rotational speed detection device, the conductive part is a conductive sheet arranged on the moving member; or

[0011] The conductive part is the conductive material on the moving member, or

[0012] The moving part is made of a conductive material.

[0013] In the specific implementation manner of the above rotational speed detection device, the rotational speed detection device further includes a reset member, which is used to drive the moving part to reset after moving.

[0014] In a second aspect, the present invention provides a control method for an air-conditioning system, and the control method includes the following steps:

[0015] Determine whether to turn on the electric heating according to the operating mode of the air-conditioning system, the rotational speed of the indoor motor, or the air volume and duration of the indoor fan.

[0016] In the specific implementation manner of the above control method for the air-conditioning system, before performing the step of "determining whether to turn on the electric heating according to the operating mode of the air-conditioning system, the rotational speed of the indoor motor, or the air volume and duration of the indoor fan", the following steps need to be performed:

[0017] Determine the air volume of the indoor fan according to the rotational speed of the indoor motor;

[0018] The rotational speed of the indoor motor is detected and determined by the rotational speed detection device as described above.

[0019] In the specific implementation manner of the above control method for the air-conditioning system, "determining whether to turn on the electric heating according to the operating mode of the air-conditioning system, the rotational speed of the indoor motor, and the duration" includes:

[0020] When the air-conditioning system is in the electric heating and heating mode, the rotational speed is not lower than the preset rotational speed, and the duration is preset, then turn on the electric heating.

[0021] In the specific implementation manner of the above control method for the air-conditioning system, "determining whether to turn on the electric heating according to the operating mode of the air-conditioning system, the rotational speed of the indoor motor, and the duration" further includes:

[0022] When the air-conditioning system is not in the electric heating and heating mode, the electric heating is in the off state;

[0023] When the air-conditioning system is in the electric heating and heating mode and the rotational speed is lower than the preset rotational speed, the electric heating is in the off state;

[0024] When the air-conditioning system is in the electric heating and heating mode, the rotational speed is not lower than the preset rotational speed, and the duration is less than the preset duration, the electric heating is in the off state.

[0025] In the specific implementation of the control method of the above air conditioning system, "determining whether to turn on the electric heating according to the operating mode of the air conditioning system, the air volume of the indoor fan, and the duration" includes: when the air conditioning system is in the electric heating heating mode, the air volume of the indoor fan is not lower than the preset air volume, and the duration is preset, then turn on the electric heating.

[0026] In the specific implementation of the control method of the above air conditioning system, "determining whether to turn on the electric heating according to the operating mode of the air conditioning system, the air volume of the indoor fan, and the duration" further includes:

[0027] When the air conditioning system is not in the electric heating heating mode, the electric heating is in the off state;

[0028] When the air conditioning system is in the electric heating heating mode and the air volume of the indoor fan is lower than the preset air volume, the electric heating is in the off state;

[0029] When the air conditioning system is in the electric heating heating mode, the air volume of the indoor fan is not lower than the preset air volume, and the duration is less than the preset duration, the electric heating is in the off state.

[0030] In the specific implementation of the control method of the above air conditioning system, the preset speed is determined according to the minimum air volume of the indoor unit.

[0031] In a third aspect, the present invention provides an air conditioning system, which includes a main control board configured to be able to execute the control method of the air conditioning system as described above.

[0032] In the specific implementation of the above air conditioning system, the detection circuit is connected to the main control board, and the main control board is used to collect the electrical signal of the detection circuit, and the main control board calculates the rotation speed of the indoor motor according to the electrical signal

[0033] In the case of adopting the above technical solution, the rotation speed detection device of the indoor unit of the present invention includes a rotating member, a moving member, and a detection circuit. The moving member and the rotating member are correspondingly arranged. When the rotor drives the rotating member to rotate, the moving member can be periodically driven to move; the detection circuit includes a first terminal and a second terminal arranged at intervals. The moving member moves periodically and fills the interval between the first terminal and the second terminal, so that the detection circuit is periodically turned on. After being turned on, an electrical signal can be generated. The rotation speed of the motor can be determined according to the frequency of the electrical signal; whether the minimum rotation speed or the minimum air volume is reached can be determined according to the rotation speed of the motor. After reaching and lasting for a certain duration, the electric heating is turned on. After reaching the minimum air volume or the minimum rotation speed and lasting for a period of time, the combustible refrigerant accumulated in the leakage of the indoor unit can be blown away to ensure that no safety accident occurs when the electric heating is turned on.

[0034] In addition, the rotational speed detection device has fewer components and a simple structure. Moreover, the detection circuit is connected to the main control board, so that the main control board can obtain the rotational speed of the motor, and then determine the air volume of the indoor unit, which can ensure the opening timing of the electric heating, and further ensure the safety of the air conditioning system. Description of the Drawings

[0035] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0036] Figure 1 is a schematic structural diagram of the rotational speed detection device provided in the first embodiment of the present invention; Figure 1 ;

[0037] Figure 2 is a schematic structural diagram of the rotational speed detection device provided in the first embodiment of the present invention; Figure 2 ;

[0038] Figure 3 is a flowchart of the control method of the air conditioning system provided in the second embodiment of the present invention;

[0039] Figure 4 is a flowchart of the control method of the air conditioning system provided in the third embodiment of the present invention.

[0040] List of reference numerals: 1, rotating member; 2, fixing member; 3, moving member; 4, detection circuit; 5, elastic member. Detailed Embodiments

[0041] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0042] It should be noted that in the description of the present invention, the terms indicating the direction or positional relationship such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the direction or positional relationship shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] In addition, it should also be noted that in the description of the present invention, unless otherwise clearly defined and limited, the terms "installation", "setting", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] The existing indoor unit cannot determine the rotational speed of the motor, resulting in the inability to control the accurate starting time of the electric heating, and it is prone to safety problems. The present invention discloses a rotational speed detection device, an air conditioning system and a control method thereof, and the following will describe them in detail with three embodiments.

[0045] As Figure 1 and 2 shown, this embodiment discloses a rotational speed detection device, which includes a rotating member 1, a moving member 3 and a detection circuit 4. The moving member 3 and the rotating member 3 are correspondingly arranged. When the rotating member 1 rotates, it can periodically drive the moving member 3 to move; specifically, the rotating member 1 is arranged on the rotor or the rotating shaft, and a connecting hole is arranged on the rotating member 1. The rotating member 1 is sleeved on the rotating shaft of the rotor and fixed by screws or keys, etc., so that the rotating member 1 cannot rotate relative to the rotating shaft, and the rotating shaft can drive the rotating member 1 to rotate, that is, the rotor can drive the rotating member 1 to rotate. The rotating member 1 is specifically in a fan shape, which can make the rotating member 1 periodically contact the moving member 3; so that the moving member 3 moves periodically.

[0046] Regarding the shape of the rotating member 1, it should be noted that although it is a fan shape in this embodiment, this is not a limitation of the present invention. Without departing from the principle of the present invention, in other embodiments, the rotating member 1 is a disc shape, and a protruding portion is arranged on the rotating member 1. During the rotation process, the protruding portion contacts the moving member 3, which can drive the moving member 3 to move periodically. Or, the rotating member 1 is a rod shape, and it can also drive the moving member 3 to move periodically during the rotation process. These do not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0047] The moving member 3 is movably arranged on the stator. When the rotor or the motor shaft drives the rotating member 1 to rotate, it can periodically drive the moving member 3 to move; specifically, the rotational speed detection device further includes a fixing member 2, which is arranged on the housing or the stator of the motor. In this embodiment, it is specifically fixed on the motor housing.

[0048] The moving member 3 is slidably arranged on the fixing member 2. Specifically, the fixing member 2 includes spaced tracks. The fixing member 2 can be an integral structure, and the spaced tracks are through holes arranged on the fixing member 2. The moving member 3 is rod-shaped and is arranged through the sliding hole (through hole);

[0049] Or, the fixing member 2 can also be a split structure, which includes a first fixing portion and a second fixing portion arranged at intervals. An interval track is formed between the first fixing portion and the second fixing portion. The moving member 3 is rod-shaped and is arranged through the sliding hole (interval track). The detection circuit 4 is connected to the moving member 3. The detection circuit includes a first terminal and a second terminal that are spaced apart. The moving member 3 moves periodically and fills the space between the first terminal and the second terminal, so that the detection circuit 4 is periodically turned on. Among them, the first terminal and the second terminal are connected to the main control board or the control module, etc. When the detection circuit is turned on or off, the electrical signal sampling circuit of the main control board can collect the on or off signal, so that the main control board can determine the on or off frequency, and then determine the rotational speed of the motor. Determine the rotational speed of the motor according to the on or off frequency of the electrical signal. Specifically, during one rotation of the rotating member 1, the moving member 3 will move once; the rotational speed of the motor can be determined according to the interval time of the movement of the moving member 3.

[0050] Regarding the number of times the moving member 3 moves when the rotating member 1 rotates one circle, it should be noted that although in this embodiment, it moves once when rotating one circle; this is not a limitation of the present invention. Without departing from the principle of the present invention, in other embodiments, during the process of the rotating member 1 rotating one circle, the moving member 3 can also be driven to move multiple times, and the rotational speed of the motor can also be determined according to the time interval of the movement of the moving member 3. These do not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0051] Specifically, the detection circuit 4 is arranged on the fixed member 2, and there is a break point at the sliding hole, that is, the detection circuit 4 is in an open circuit state under normal circumstances.

[0052] A conductive part is arranged on the moving member 3, which is specifically located near the sliding hole and on the side close to the rotating member 1, so that the rotating member 1 can drive the moving member 3 to move away from the rotating member 1, so that the conductive part can move to the break point to turn on the detection circuit 4, so that the detection circuit 4 can generate an electrical signal, so that the detection circuit 4 can detect the rotational speed of the motor.

[0053] The conductive part is a conductive sheet arranged on the moving member 3, and the conductive sheet is specifically arranged on the outer surface of the conductive member. Under normal circumstances, the conductive sheet is located on the side close to the rotating member 1 and does not contact the break point. When the rotating member 1 drives the moving member 3 to move, the rotating member 1 contacts the break point, and the detection circuit 4 can be turned on. At least the part of the moving member 3 close to the sliding hole is made of insulating material or an insulating layer is coated on the surface of the moving member 3, which can ensure that the moving member 3 cannot turn on the detection circuit 4 under normal circumstances.

[0054] Alternatively, the moving member 3 is a conductive rod made of a conductive material, and the diameters of different positions of the moving member 3 are different. In the normal state, the diameter of the conductive rod located between the first terminal and the second terminal is smaller than the distance between the first terminal and the second terminal, that is, smaller than the inner diameter of the sliding hole, and the first terminal and the second terminal are in an open state. When the rotating member drives the moving member 3 to move, the diameter of the moving member 3 located between the first terminal and the second terminal is equal to the distance between the first terminal and the second terminal, that is, equal to the inner diameter of the sliding hole. At this time, the first terminal and the second terminal are connected, and the detection circuit 4 is turned on.

[0055] Regarding the conductive part, it should be noted that although in this embodiment it is specifically a conductive sheet, this is not a limitation on the present invention. In other embodiments, the conductive part is the conductive material on the moving member 3; that is, the part of the moving member 3 that can cooperate with the break point of the detection circuit 4 is the conductive material, specifically copper metal. The part of the moving member 3 close to the sliding hole is made of an insulating material or an insulating layer is coated on the surface of the moving member 3, which can ensure that the moving member 3 cannot conduct the detection circuit 4 under normal circumstances. These do not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0056] The rotational speed detection device further includes a reset member, which is used to drive the moving member 3 to reset after moving. Specifically, the reset member is specifically a compression spring, which abuts against the moving member 3 and can drive the moving member 3 to move in the direction close to the rotating member 1 to reset the moving member 3.

[0057] Regarding the reset member, it should be noted that although in this embodiment a reset member is used to drive the moving member 3 to reset, this is not a limitation on the present invention. In other embodiments, when the motor shaft is vertically arranged, the moving member 3 is arranged above the rotating member 1, and under the action of gravity, the moving member 3 can return to its original position. It is preferred to use a reset member, and the driving force of the reset member is large, which can enable the moving member 3 to quickly return to its original position.

[0058] Embodiment 2

[0059] This embodiment discloses an air conditioning system, which includes an indoor unit and an outdoor unit. The indoor unit includes a main control board, an indoor motor, an indoor heat exchanger, and an electric heater; that is, the main control board is arranged in the indoor unit.

[0060] Regarding the main control board, it should be noted that although in this embodiment it is arranged in the indoor unit, this is not a limitation on the present invention. On the premise of not deviating from the principle of the present invention, in other embodiments, those skilled in the art can choose to arrange the main control board in the outdoor unit, which can all enable the main control board to control the operation of the air conditioning system. These do not deviate from the basic principle of the present invention and will fall within the protection scope of the present invention.

[0061] The main control board is used to control the air - conditioning system according to the instructions of the remote control, the smart terminal and the buttons on the indoor unit, so that the air - conditioning system operates according to the user's needs.

[0062] The main control board is also configured to be able to execute the control method of the air - conditioning system. The control method of the air - conditioning system includes the following steps:

[0063] Determine whether to turn on the electric heating according to the operating mode of the air - conditioning system, the rotation speed of the indoor motor and the duration.

[0064] Among them, the rotation speed of the motor is detected and determined according to the rotation speed detection device described in Embodiment 1. That is, a rotation speed detection device in Embodiment 1 is provided at the electrode of the indoor unit, and the detection circuit 4 of the detection device is connected to the main control board. An electrical signal sampling circuit is provided on the main control board, and the electrical signal sampling circuit can collect the electrical signal of the detection circuit 4, and determine the rotation speed of the motor according to the time interval of the detected electrical signal. Among them, the preset rotation speed is determined according to the minimum air volume of the indoor unit. Specifically, the preset rotation speed is the rotation speed corresponding to the minimum air volume. The minimum air volume is the minimum air volume required by the regulations and standards. Specifically, the minimum air volume Q min = 30×mc / LFL, where mc is the weight of the flammable refrigerant filled, and LFL is the lower flammable limit of the flammable refrigerant, which is a constant; that is, the minimum air volume is related to the filling amount and the type of the flammable refrigerant.

[0065] "Determine whether to turn on the electric heating according to the operating mode of the air - conditioning system, the rotation speed of the indoor motor and the duration" specifically includes:

[0066] When the air - conditioning system is in the electric - heating heating mode, the rotation speed is not lower than the preset rotation speed, and the duration is preset, then turn on the electric heating. The rotation speed not being lower than the preset rotation speed means that the air volume reaches the preset air volume, and the duration being preset means that the air volume is relatively stable. At this time, the refrigerant leaked and accumulated at the indoor unit can be completely blown away. Turning on the electric heating at this time can ensure the safety of the air - conditioner operation.

[0067] When the air - conditioning system is not in the electric - heating heating mode, the electric heating is in the off state; among them, not being in the electric - heating heating mode can be being in the cooling mode, the defrosting mode or the heat - pump heating mode. In these modes, there is no need for electric heating, so the electric heating is in the off state.

[0068] When the air - conditioning system is in the electric - heating heating mode and the rotation speed is lower than the preset rotation speed, the electric heating is in the off state; the rotation speed being lower than the preset rotation speed means that the air volume of the fan does not reach the preset air volume. The preset air volume is the minimum air volume. If the air volume does not reach the minimum air volume, it is very likely that the accumulated refrigerant cannot be blown away, and turning on the electric heating will cause safety problems. Therefore, if the rotation speed does not reach the preset rotation speed, the electric heating is not turned on.

[0069] When the air - conditioning system is in the electric - heating heating mode, the rotational speed is not lower than the preset rotational speed, and the duration is less than the preset duration, the electric heating is in the off state. Although the rotational speed is not lower than the preset rotational speed, the duration being less than the preset duration indicates unstable air volume. Unstable air volume is likely to cause the accumulated refrigerant not to be completely blown away. Therefore, to ensure safety, the electric heating is not turned on.

[0070] As Figure 3 shown, the control method of the air - conditioning system includes the following detailed steps:

[0071] S1. Obtain the operating mode of the air - conditioning system;

[0072] S2. Determine whether the operating mode is the electric - heating heating mode; if so, proceed to step S3;

[0073] S3. Obtain the rotational speed of the indoor motor;

[0074] S4. Determine whether the rotational speed is lower than the preset rotational speed; if so, the electric heating is in the off state; if not, proceed to step S5;

[0075] S5. Obtain the duration for which the rotational speed reaches the preset rotational speed;

[0076] S6. Determine whether the duration reaches the preset duration; if so, turn on the electric heating; if not, the electric heating is in the off state.

[0077] Embodiment III

[0078] This embodiment discloses an air - conditioning system, which has the same structure as the air - conditioning system in Embodiment II. The difference lies in the control method of the air - conditioning system. The control method of this air - conditioning system includes the following steps:

[0079] Determine whether to turn on the electric heating according to the operating mode of the air - conditioning system, the air volume of the indoor fan, and the duration.

[0080] The air volume of the indoor fan is determined according to the rotational speed of the indoor motor. Among them, the rotational speed of the motor is detected and determined by the rotational - speed detection device described in Embodiment I. That is, the rotational - speed detection device in Embodiment I is provided at the electrode of the indoor unit, and the detection circuit 4 of the detection device is connected to the main control board. An electric - signal sampling circuit is provided on the main control board. The electric - signal sampling circuit can collect the electric signals of the detection circuit 4, and determine the rotational speed of the motor according to the time interval of the detected electric signals.

[0081] Specifically, "determine whether to turn on the electric heating according to the operating mode of the air - conditioning system, the air volume of the indoor fan, and the duration" specifically includes:

[0082] When the air - conditioning system is in the electric - heating heating mode, the air volume is not less than the preset air volume, and it lasts for the preset duration, then the electric heating is turned on. The air volume not being less than the preset air volume and lasting for the preset duration means that the air volume is relatively stable. At this time, the refrigerant leaked and accumulated at the indoor unit can be completely blown away. Turning on the electric heating at this time can ensure the safe operation of the air conditioner.

[0083] Among them, the preset air volume is determined according to the minimum air volume of the indoor unit. Specifically, the preset air volume is the minimum air volume of the indoor unit. The minimum air volume is the minimum air volume required by the regulations and standards. Specifically, the minimum air volume Q min = 30×mc / LFL, where mc is the weight of the flammable refrigerant filled, and LFL is the lower flammability limit of the flammable refrigerant, which is a constant specifically; that is, the minimum air volume is related to the filling amount and the type of flammable refrigerant.

[0084] When the air - conditioning system is not in the electric - heating heating mode, the electric heating is in the off state; among them, not being in the electric - heating heating mode can be being in the cooling mode, defrosting mode or heat - pump heating mode. In these modes, there is no need for electric heating, so the electric heating is in the off state.

[0085] When the air - conditioning system is in the electric - heating heating mode and the air volume is lower than the preset air volume, the electric heating is in the off state; when the air volume is lower than the preset air volume, it means that the air volume of the fan has not reached the preset air volume. If the air volume has not reached the minimum air volume, it is very likely that the accumulated refrigerant cannot be blown away, and safety problems will occur when the electric heating is turned on. Therefore, when the air volume has not reached the preset air volume, the electric heating is not turned on.

[0086] When the air - conditioning system is in the electric - heating heating mode, the air volume is not less than the preset air volume, but the duration is less than the preset duration, the electric heating is in the off state. Although the air volume is not less than the preset air volume, the duration being less than the preset duration means that the air volume is unstable. An unstable air volume is very likely to cause the accumulated refrigerant not to be completely blown away. Therefore, in order to ensure safety, the electric heating is not turned on.

[0087] As Figure 4 shown, the control method of this air - conditioning system includes the following detailed steps:

[0088] S1. Obtain the operating mode of the air - conditioning system;

[0089] S2. Determine whether the operating mode is the electric - heating heating mode; if so, proceed to step S3;

[0090] S3. Obtain the air volume of the indoor fan;

[0091] S4. Determine whether the air volume is lower than the preset air volume. If so, the electric heating is in the off state; if not, proceed to step S5;

[0092] S5. Obtain the duration during which the air volume reaches the preset air volume;

[0093] S6. Determine whether the duration reaches the preset duration. If so, turn on the electric heating; if not, the electric heating is in the off state.

[0094] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A rotational speed detection device, characterized in that, It includes: A rotating member (1), A moving member (3), the moving member and the rotating member are correspondingly arranged, when the rotating member (1) rotates, it can periodically drive the moving member (3) to move; A detection circuit (4), including a first terminal and a second terminal arranged at intervals, the moving member (3) moves periodically and fills the interval between the first terminal and the second terminal, so that the detection circuit (4) is periodically turned on.

2. The rotational speed detection device according to claim 1, characterized in that, The rotational speed detection device further includes a fixing member (2), the fixing member has an interval track, the moving member (3) is slidably arranged on the interval track, a conductive part is arranged on the moving member (3), the first terminal and the second terminal are respectively connected to both sides of the interval track, after the moving member (3) moves, the conductive part can connect the first terminal and the second terminal to turn on the detection circuit (4).

3. The rotational speed detection device according to claim 2, characterized in that The conductive part is a conductive sheet arranged on the moving member (3); or The conductive part is the conductive material on the moving member (3), or The moving member is made of conductive material.

4. The rotational speed detection device according to claim 1, wherein The rotational speed detection device further includes a reset member, which is used to drive the moving member (3) to reset after moving.

5. A control method for an air conditioning system, characterized in that, It includes the following steps: Determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the rotational speed of the indoor motor or the air volume and duration of the indoor fan.

6. The control method according to claim 5, wherein Before performing the step of "determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the rotational speed of the indoor motor or the air volume and duration of the indoor fan", the following steps need to be performed: Determine the air volume of the indoor fan according to the rotational speed of the indoor motor; The rotational speed of the indoor motor is detected and determined according to the rotational speed detection device described in any one of claims 1-4.

7. The control method according to claim 5, characterized in that "Determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the rotational speed of the indoor motor and the duration" includes: When the air conditioning system is in the electric heating heating mode, the rotational speed is not lower than the preset rotational speed, and the duration is preset, then turn on the electric heating; Preferably, "determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the rotational speed of the indoor motor and the duration" further includes: When the air conditioning system is not in the electric heating heating mode, the electric heating is in the off state; When the air conditioning system is in the electric heating heating mode and the rotational speed is lower than the preset rotational speed, the electric heating is in the off state; When the air conditioning system is in the electric heating heating mode, the rotational speed is not lower than the preset rotational speed, and the duration is less than the preset duration, the electric heating is in the off state.

8. The control method according to claim 5, characterized in that "Determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the air volume of the indoor fan and the duration" includes: when the air conditioning system is in the electric heating heating mode, the air volume of the indoor fan is not lower than the preset air volume, and the duration is preset, then turn on the electric heating; and / or "Determine whether to turn on the electric heating according to the operating mode of the air conditioning system, the air volume of the indoor fan and the duration" further includes: When the air conditioning system is not in the electric heating heating mode, the electric heating is in the off state; When the air conditioning system is in the electric heating mode and the air volume of the indoor fan is lower than the preset air volume, the electric heating is in the off state; When the air conditioning system is in the electric heating mode, the air volume of the indoor fan is not lower than the preset air volume, and the duration is less than the preset duration, the electric heating is in the off state.

9. The control method according to claims 5-8, characterized in that The preset speed is determined according to the minimum air volume of the indoor unit.

10. An air conditioning system, characterized in that The air conditioning system includes a main control board configured to execute the control method of the air conditioning system according to any one of claims 5-19; Preferably, the detection circuit (4) is connected to the main control board, the main control board is used to collect the electrical signal of the detection circuit (4), and the main control board calculates the speed of the indoor motor according to the electrical signal.

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