Magnetic levitation motor and cooling method, device, storage medium and program product thereof

Abstract

The application discloses a kind of cooling method, device, magnetic suspension motor of magnetic suspension motor, storage medium and computer program product, motor winding of magnetic suspension motor is equipped with coolant pipeline, and electronic expansion valve is equipped on coolant pipeline;The method comprises: after magnetic suspension motor starts to work, the target opening of electronic expansion valve is determined according to the temperature of motor winding;Pulse mode is used to power on electronic expansion valve, and the energization time of electronic expansion valve is controlled according to the action frequency of electronic expansion valve, so that the opening of electronic expansion valve reaches the target opening while reducing the energization time of electronic expansion valve, reduce the heat at the place of electronic expansion valve.The scheme, by pulse mode to power on electronic expansion valve, and the energization time is controlled according to the action frequency of electronic expansion valve, so that the energization time of electronic expansion valve is reduced, the heat at the place of electronic expansion valve is reduced, avoid electronic expansion valve high temperature failure, ensure that magnetic suspension motor is stably operated.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation motors, and specifically relates to a cooling method, device, magnetic levitation motor, storage medium, and computer program product for a magnetic levitation motor. Background Technology

[0002] During the operation of a magnetic levitation motor, the motor windings generate a large amount of heat due to the rotor cutting magnetic field lines, requiring the use of coolant to cool the motor windings.

[0003] When cooling motor windings, an electronic expansion valve installed at the front end of the cooling channel allows for precise control of the coolant flow, maintaining the motor winding temperature within a stable range. However, because motor power changes dynamically, the motor winding temperature also fluctuates. To stabilize the winding temperature, the electronic expansion valve remains continuously energized and operates frequently, accumulating heat at its location. Excessive heat can cause the electronic expansion valve to malfunction, ultimately leading to ineffective temperature control of the motor windings.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a cooling method, device, magnetic levitation motor, storage medium, and computer program product for a magnetic levitation motor. This addresses the problem in related solutions where excessive heat accumulation at the electronic expansion valve causes valve failure, resulting in ineffective control of the motor winding temperature. The invention achieves this by using pulsed energizing of the electronic expansion valve and controlling the energizing time according to the valve's operating frequency. This reduces the energizing time of the electronic expansion valve, lowers the heat at the valve, prevents high-temperature valve failure, effectively controls the motor winding temperature, and ensures stable operation of the magnetic levitation motor.

[0006] This invention provides a cooling method for a magnetic levitation motor, wherein a coolant pipe is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipe; the method includes: after the magnetic levitation motor starts working, acquiring the temperature of the motor winding and the operating frequency of the electronic expansion valve; determining the target opening degree of the electronic expansion valve based on the temperature of the motor winding; energizing the electronic expansion valve in a pulse manner, and controlling the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve while achieving the target opening degree, thereby reducing the heat at the electronic expansion valve.

[0007] In some embodiments, the electronic expansion valve has a four-phase coil and a valve body; by controlling each phase coil of the four-phase coil to be energized in sequence according to a set energizing order, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

[0008] In some embodiments, determining the target opening degree of the electronic expansion valve based on the temperature of the motor winding includes: substituting the temperature of the motor winding into a preset calculation formula to calculate the target opening degree of the electronic expansion valve; the preset calculation formula is:

[0009] U pre-sat =U p (k)+U i (k);

[0010] Among them, U pre-sat U represents the target opening degree of the electronic expansion valve. p (k) represents the proportional output, U p (k)=K p err(k), err(k) = -(Ref - Fdb), where Fdb is the temperature of the motor winding, Ref is the reference temperature of the motor winding, and K p U is the proportional gain coefficient; i (k) represents the integral output.

[0011] In some embodiments, controlling the energizing time of the electronic expansion valve according to its operating frequency includes: determining the reciprocal of the operating frequency of the electronic expansion valve as the pulse period; and using the result of multiplying the pulse period by a set duty cycle as the energizing time of the electronic expansion valve.

[0012] In conjunction with the above method, another aspect of the present invention provides a cooling device for a magnetic levitation motor, wherein a coolant pipe is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipe; the cooling device includes: an acquisition unit configured to acquire the temperature of the motor winding and the operating frequency of the electronic expansion valve after the magnetic levitation motor starts working; a control unit configured to determine the target opening degree of the electronic expansion valve based on the temperature of the motor winding; the control unit is further configured to energize the electronic expansion valve in a pulse manner and control the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve while achieving the target opening degree, thereby reducing the heat at the electronic expansion valve.

[0013] In some embodiments, the electronic expansion valve has a four-phase coil and a valve body; by controlling each phase coil of the four-phase coil to be energized in sequence according to a set energizing order, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

[0014] In some embodiments, the control unit determines the target opening degree of the electronic expansion valve based on the temperature of the motor windings, including: substituting the temperature of the motor windings into a preset calculation formula to calculate the target opening degree of the electronic expansion valve; the preset calculation formula is:

[0015] U pre-sat =U p (k)+U i (k);

[0016] Among them, U pre-sat U represents the target opening degree of the electronic expansion valve. p (k) represents the proportional output, U p (k)=K p err(k), err(k) = -(Ref - Fdb), where Fdb is the temperature of the motor winding, Ref is the reference temperature of the motor winding, and K p U is the proportional gain coefficient; i (k) represents the integral output.

[0017] In some embodiments, the control unit controls the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, including: determining the reciprocal of the operating frequency of the electronic expansion valve as the pulse period; and using the result of multiplying the pulse period by a set duty cycle as the energizing time of the electronic expansion valve.

[0018] In conjunction with the above-mentioned device, the present invention further provides a magnetic levitation motor, including: the cooling device for the magnetic levitation motor described above.

[0019] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device containing the storage medium is controlled to perform the cooling method for the magnetic levitation motor described above.

[0020] In conjunction with the above method, the present invention further provides a computer program product comprising a computer program that, when processed and executed, implements the steps of the cooling method for the magnetic levitation motor described above.

[0021] The present invention involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the operating frequency of the electronic expansion valve. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the electronic expansion valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to the operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the electronic expansion valve and preventing high-temperature failure of the electronic expansion valve. This effectively controls the temperature of the motor winding and ensures the stable operation of the magnetic levitation motor.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic flowchart of an embodiment of the cooling method for the magnetic levitation motor of the present invention;

[0025] Figure 2 This is a schematic diagram of a structure of an embodiment of the cooling device for the magnetic levitation motor of the present invention;

[0026] Figure 3 This is a schematic diagram of the motor winding cooling pipes.

[0027] Figure 4 This is a schematic diagram showing the wiring method and valve opening / closing method of an electronic expansion valve;

[0028] Figure 5 This is a pulse control current diagram for an electronic expansion valve.

[0029] Figure 6 A schematic diagram of the process for controlling the opening degree of an electronic expansion valve;

[0030] Figure 7 This is a schematic diagram of the process for controlling the energization of an electronic expansion valve using a pulse method.

[0031] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0032] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] According to an embodiment of the present invention, a cooling method for a magnetic levitation motor is provided, wherein a coolant pipe is provided at the motor winding of the magnetic levitation motor; coolant flows within the coolant pipe, and the coolant can cool the motor winding; an electronic expansion valve is provided on the coolant pipe; the electronic expansion valve is used to control the flow rate of the coolant. Figure 3 As shown, the coolant pipe is wound around the motor windings. Coolant enters the pipe through the cooling inlet and cools the motor windings. Afterwards, the coolant flows out through the return pipe and into the intake pipe, completing one cycle. An electronic expansion valve is installed at the cooling inlet. By controlling the opening of the electronic expansion valve, the flow rate of coolant into the coolant pipe is controlled. A larger coolant flow rate lowers the temperature of the motor windings, while a smaller coolant flow rate raises the temperature of the motor windings, thus maintaining the temperature of the motor windings within a certain range.

[0035] In some embodiments, the electronic expansion valve has a four-phase coil and a valve body; by controlling each phase coil of the four-phase coil to be energized in sequence according to a set energizing order, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

[0036] An electronic expansion valve is essentially a stepper motor. In this solution, the electronic expansion valve, based on its coil winding method, is a five-wire, four-phase, unipolar stepper motor. The wiring of the electronic expansion valve is as follows: Figure 4 As shown in (a) and (b), the electronic expansion valve adopts a common anode wiring method. The out1 of the drive signal is connected to terminal A of the electronic expansion valve, and the out2 of the drive signal is connected to terminal B of the electronic expansion valve. The drive signal output OUT3 is connected to terminal B of the electronic expansion valve, and the drive signal output OUT4 is connected to terminal B of the electronic expansion valve. The COM terminal is connected to a +24V power supply.

[0037] The electronic expansion valve is controlled by a four-phase eight-step control method, such as... Figure 4As shown in (c), during the control process, one or two phases are always energized. The shaded area in the figure represents the energized phase. That is, each step action consists of energizing and de-energizing two or one of the four phases. In the first step, phase A is energized, causing the rotor of the motor to be attracted by the magnetic force generated by the coil, and the rotor rotates to a position aligned with the coil of phase A. In the second step, phases A and B are energized, and the rotor is attracted by the magnetic force of both coils, moving to a position between the two coils. In the third step, only phase B is energized, and the rotor rotates to a position aligned with the coil of phase B. Steps four through eight follow the same pattern, that is, single-phase energization and two-phase energization alternate, causing the rotor to rotate, thereby precisely controlling the operating frequency and opening degree of the electronic expansion valve.

[0038] For example Figure 4 The wiring methods for electronic expansion valves shown in (a) and (b) generally use square wave control for energization, such as... Figure 5 The waveform shown in (a) indicates that during the control process of the electronic expansion valve, one or two phases are always energized. However, since the electronic expansion valve is always energized, heat will continue to accumulate at the electronic expansion valve. If this heat cannot be dissipated in time, the control of the electronic expansion valve may fail, and thus the temperature of the motor windings cannot be controlled.

[0039] This solution uses pulse control to control the electronic expansion valve, controlling the energizing time of each phase in each pulse cycle, thereby reducing the energizing time of each phase, reducing the heat generated by the coil, and allowing the heat at the electronic expansion valve to dissipate in a timely manner, achieving a cooling effect.

[0040] like Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The cooling method for the magnetic levitation motor may include steps S110 to S130.

[0041] In step S110, after the magnetic levitation motor starts working, the temperature of the motor winding and the operating frequency of the electronic expansion valve are obtained.

[0042] The operating frequency of the electronic expansion valve is set by the system; it can be the frequency at which the electronic expansion valve adjusts the coolant flow rate, i.e., the number of times the electronic expansion valve adjusts the coolant flow rate per unit time. Since the temperature sampling point of the motor windings is not located at the same position as the electronic expansion valve, it is usually set at the outlet of the return gas line. Therefore, when the opening of the electronic expansion valve increases, the temperature at the inlet of the coolant line where the electronic expansion valve is located will decrease, but the temperature at the sampling point will not change immediately; when the opening of the electronic expansion valve decreases, the temperature at the inlet of the coolant line where the electronic expansion valve is located will rise, but the temperature at the sampling point will not change immediately. Thus, there is a lag in the detection of temperature changes in the motor windings. Therefore, when the temperature at the sampling point of the motor windings changes, it indicates that the temperature of the entire motor windings is basically the same. Based on the characteristic that the temperature at the sampling point changes only after a certain period of time following a change in the opening of the electronic expansion valve, the service life of the electronic expansion valve can be extended by extending its control cycle.

[0043] In step S120, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding.

[0044] In some implementations, step S120, which involves determining the target opening of the electronic expansion valve based on the temperature of the motor winding, includes: substituting the temperature of the motor winding into a preset calculation formula to calculate the target opening of the electronic expansion valve.

[0045] The formula for calculating the target opening of the electronic expansion valve based on the motor winding temperature can be the PI calculation formula, specifically:

[0046] U pre-sat =U p (k)+U i (k);

[0047] In the formula, U pre-sat For the target opening degree of the electronic expansion valve, U p (k) represents the proportional output, U p (k)=K p err(k), err(k) = -(Ref - Fdb), takes a negative value because when the temperature of the motor windings is lower than the reference temperature, the opening of the electronic expansion valve needs to be adjusted, and it is negatively correlated with Ref - Fdb; K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, Fdb is the temperature of the motor winding; Ui(k) is the integral output, Ui(k) = U i (k-1)+KiU p (k), default

[0048] Optionally, after obtaining the target opening degree of the electronic expansion valve according to the PI calculation formula, the target opening degree can be limited to prevent oversaturation of the electronic expansion valve. The formula for limiting the opening degree is:

[0049]

[0050] U(k) is the target opening degree after the electronic expansion valve is limited. max U is the maximum opening of the electronic expansion valve. min This represents the minimum opening degree of the electronic expansion valve. The valve opening is calculated using the PI formula. When the motor winding temperature is higher than the reference temperature, the valve opening increases; when the motor winding temperature is lower than the reference temperature, the valve opening decreases. The greater the temperature difference, the greater the opening adjustment. By limiting the pre-output opening of the electronic expansion valve, it is possible to prevent the valve from entering a saturated state during adjustment, resulting in more sensitive opening adjustment and more precise motor winding temperature control.

[0051] In step S130, the electronic expansion valve is energized in a pulse manner, and the energizing time of the electronic expansion valve is controlled according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve and reduce the heat at the electronic expansion valve while making the opening degree of the electronic expansion valve reach the target opening degree.

[0052] The pulse mode is a power supply method that uses periodic pulse signals to provide electrical energy, with the pulse signals provided by a pulse generator.

[0053] Figure 6 A flowchart illustrating the control of the opening degree of the electronic expansion valve, as shown below. Figure 6 As shown, the method includes:

[0054] Step 1: Upload the temperature of the motor windings to the host computer. The host computer will calculate the preset opening degree required for the electronic expansion valve based on the temperature of the motor windings.

[0055] Step 2: The host computer controls the electronic expansion valve according to the set action frequency and performs pulse control according to the set duty cycle to make the electronic expansion valve reach the preset opening degree.

[0056] By using pulse control to energize the electronic expansion valve, the energizing time of each phase coil in the electronic expansion valve is reduced without affecting the valve's operating frequency. This reduces the heat generated by the coil and effectively dissipates heat from the electronic expansion valve, ensuring stable operation, extending its service life, and preventing valve failure that could lead to ineffective temperature control of the motor windings, thus ensuring stable operation of the magnetic levitation motor.

[0057] In some embodiments, step S130, the specific process of controlling the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, includes: determining the reciprocal of the operating frequency of the electronic expansion valve as the pulse period; and using the result of multiplying the pulse period by a set duty cycle as the energizing time of the electronic expansion valve.

[0058] When controlling the energizing time of the electronic expansion valve, the host computer first sets the operating frequency f of the electronic expansion valve and calculates the conduction time based on the operating frequency f. The conduction time T = (1 / f) * duty cycle, and the duty cycle is set according to the actual situation. Then, based on the conduction time T, a pulse control method is used to control the conduction time of each phase coil in the electronic expansion valve. Figure 5 As shown in (b), taking the first pulse as an example, phase A is energized only for a portion of the time, with a high level when energized and a low level when not energized. The electronic expansion valve operates normally when energized and does not operate when not energized. During this time, the coil does not generate heat and dissipates any accumulated heat.

[0059] ˉˉ

[0060] As long as the voltage between terminals A, B, and B is the same as that between terminals COM, it is equivalent to the coil being de-energized. For example, the coil can be de-energized if terminals OUT1 to OUT4 of the host computer control driver chip are all at a high level.

[0061] The pulse control method not only reduces the temperature at the electronic expansion valve, but also does not change the operating frequency of the electronic expansion valve.

[0062] Figure 7 This is a schematic diagram of a process for controlling the energization of an electronic expansion valve using a pulse method. The method includes:

[0063] Step 11: The host computer sets the operating frequency f of the electronic expansion valve and calculates the duty cycle time T = (1 / f) * duty cycle, where the duty cycle is the set value.

[0064] Step 12: The host computer sequentially controls the power supply to each phase of the electronic expansion valve via the control chip pins. After the power supply time reaches the duty cycle time, the control chip outputs a high level, thus de-energizing the electronic expansion valve.

[0065] The technical solution of this embodiment involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the operating frequency of the electronic expansion valve. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the electronic expansion valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to the operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the electronic expansion valve and preventing high-temperature failure of the electronic expansion valve. This effectively controls the temperature of the motor winding and ensures the stable operation of the magnetic levitation motor.

[0066] According to an embodiment of the present invention, a cooling device for a magnetic levitation motor corresponding to a cooling method for a magnetic levitation motor is also provided. A coolant pipe is provided at the motor winding of the magnetic levitation motor; coolant flows within the coolant pipe, and the coolant is capable of cooling the motor winding; an electronic expansion valve is provided on the coolant pipe; the electronic expansion valve is used to control the flow rate of the coolant. Figure 3 As shown, the coolant pipe is wound around the motor windings. Coolant enters the pipe through the cooling inlet and cools the motor windings. Afterwards, the coolant flows out through the return pipe and into the intake pipe, completing one cycle. An electronic expansion valve is installed at the cooling inlet. By controlling the opening of the electronic expansion valve, the flow rate of coolant into the coolant pipe is controlled. A larger coolant flow rate lowers the temperature of the motor windings, while a smaller coolant flow rate raises the temperature of the motor windings, thus maintaining the temperature of the motor windings within a certain range.

[0067] In some embodiments, the electronic expansion valve has a four-phase coil and a valve body; by controlling each phase coil of the four-phase coil to be energized in sequence according to a set energizing order, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

[0068] An electronic expansion valve is essentially a stepper motor. In this solution, the electronic expansion valve, based on its coil winding method, is a five-wire, four-phase, unipolar stepper motor. The wiring of the electronic expansion valve is as follows: Figure 4 As shown in (a) and (b), the electronic expansion valve adopts a common anode wiring method. The out1 of the drive signal is connected to terminal A of the electronic expansion valve, and the out2 of the drive signal is connected to terminal B of the electronic expansion valve. The drive signal output OUT3 is connected to terminal B of the electronic expansion valve, and the drive signal output OUT4 is connected to terminal B of the electronic expansion valve. The COM terminal is connected to a +24V power supply.

[0069] The electronic expansion valve is controlled by a four-phase eight-step control method, such as... Figure 4 As shown in (c), during the control process, one or two phases are always energized. The shaded area in the figure represents the energized phase. That is, each step action consists of energizing and de-energizing two or one of the four phases. In the first step, phase A is energized, causing the rotor of the motor to be attracted by the magnetic force generated by the coil, and the rotor rotates to a position aligned with the coil of phase A. In the second step, phases A and B are energized, and the rotor is attracted by the magnetic force of both coils, moving to a position between the two coils. In the third step, only phase B is energized, and the rotor rotates to a position aligned with the coil of phase B. Steps four through eight follow the same pattern, that is, single-phase energization and two-phase energization alternate, causing the rotor to rotate, thereby precisely controlling the operating frequency and opening degree of the electronic expansion valve.

[0070] For example Figure 4 The wiring methods for electronic expansion valves shown in (a) and (b) generally use square wave control for energization, such as... Figure 5 The waveform shown in (a) indicates that during the control process of the electronic expansion valve, one or two phases are always energized. However, since the electronic expansion valve is always energized, heat will continue to accumulate at the electronic expansion valve. If this heat cannot be dissipated in time, the control of the electronic expansion valve may fail, and thus the temperature of the motor windings cannot be controlled.

[0071] This solution uses pulse control to control the electronic expansion valve, controlling the energizing time of each phase in each pulse cycle, thereby reducing the energizing time of each phase, reducing the heat generated by the coil, and allowing the heat at the electronic expansion valve to dissipate in a timely manner, achieving a cooling effect.

[0072] See Figure 2 The diagram shows a structural schematic of an embodiment of the device of the present invention. The cooling device for the magnetic levitation motor may include: an acquisition unit 102 and a control unit 104.

[0073] The acquisition unit 102 is configured to acquire the temperature of the motor windings and the operating frequency of the electronic expansion valve after the magnetic levitation motor starts working. The specific functions and processing of the acquisition unit 102 are described in step S110.

[0074] The operating frequency of the electronic expansion valve is set by the system; it can be the frequency at which the electronic expansion valve adjusts the coolant flow rate, i.e., the number of times the electronic expansion valve adjusts the coolant flow rate per unit time. Since the temperature sampling point of the motor windings is not located at the same position as the electronic expansion valve, it is usually set at the outlet of the return gas line. Therefore, when the opening of the electronic expansion valve increases, the temperature at the inlet of the coolant line where the electronic expansion valve is located will decrease, but the temperature at the sampling point will not change immediately; when the opening of the electronic expansion valve decreases, the temperature at the inlet of the coolant line where the electronic expansion valve is located will rise, but the temperature at the sampling point will not change immediately. Thus, there is a lag in the detection of temperature changes in the motor windings. Therefore, when the temperature at the sampling point of the motor windings changes, it indicates that the temperature of the entire motor windings is basically the same. Based on the characteristic that the temperature at the sampling point changes only after a certain period of time following a change in the opening of the electronic expansion valve, the service life of the electronic expansion valve can be extended by extending its control cycle.

[0075] Control unit 104 is configured to determine the target opening degree of the electronic expansion valve based on the temperature of the motor windings. The specific functions and processing of control unit 104 are described in step S120.

[0076] In some embodiments, the specific process by which the control unit 104 determines the target opening degree of the electronic expansion valve based on the temperature of the motor winding includes: substituting the temperature of the motor winding into a preset calculation formula to calculate the target opening degree of the electronic expansion valve.

[0077] The formula for calculating the target opening of the electronic expansion valve based on the motor winding temperature can be the PI calculation formula, specifically:

[0078] U pre-sat =U p (k)+U i (k);

[0079] In the formula, U pre-sat For the target opening degree of the electronic expansion valve, U p (k) represents the proportional output, U p (k)=K p err(k), err(k) = -(Ref - Fdb), takes a negative value because when the temperature of the motor windings is lower than the reference temperature, the opening of the electronic expansion valve needs to be adjusted, and it is negatively correlated with Ref - Fdb; K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, Fdb is the temperature of the motor winding; Ui(k) is the integral output, Ui(k) = U i (k-1)+KiU p (k), default

[0080] Optionally, after obtaining the target opening degree of the electronic expansion valve according to the PI calculation formula, the target opening degree can be limited to prevent oversaturation of the electronic expansion valve. The formula for limiting the opening degree is:

[0081]

[0082] U(k) is the target opening degree after the electronic expansion valve is limited. max U is the maximum opening of the electronic expansion valve. min This represents the minimum opening degree of the electronic expansion valve. The valve opening is calculated using the PI formula. When the motor winding temperature is higher than the reference temperature, the valve opening increases; when the motor winding temperature is lower than the reference temperature, the valve opening decreases. The greater the temperature difference, the greater the opening adjustment. By limiting the pre-output opening of the electronic expansion valve, it is possible to prevent the valve from entering a saturated state during adjustment, resulting in more sensitive opening adjustment and more precise motor winding temperature control.

[0083] The control unit 104 is also configured to energize the electronic expansion valve in a pulse manner and control the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve while achieving the target opening degree, thereby reducing the heat at the electronic expansion valve. For the specific functions and processing of this control unit 104, please refer to step S130.

[0084] The pulse mode is a power supply method that uses periodic pulse signals to provide electrical energy, with the pulse signals provided by a pulse generator.

[0085] Figure 6 A flowchart illustrating the control of the opening degree of the electronic expansion valve, as shown below. Figure 6 As shown, the method includes:

[0086] Step 1: Upload the temperature of the motor windings to the host computer. The host computer will calculate the preset opening degree required for the electronic expansion valve based on the temperature of the motor windings.

[0087] Step 2: The host computer controls the electronic expansion valve according to the set action frequency and performs pulse control according to the set duty cycle to make the electronic expansion valve reach the preset opening degree.

[0088] By using pulse control to energize the electronic expansion valve, the energizing time of each phase coil in the electronic expansion valve is reduced without affecting the valve's operating frequency. This reduces the heat generated by the coil and effectively dissipates heat from the electronic expansion valve, ensuring stable operation, extending its service life, and preventing valve failure that could lead to ineffective temperature control of the motor windings, thus ensuring stable operation of the magnetic levitation motor.

[0089] In some embodiments, the control unit 104 controls the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, including: determining the reciprocal of the operating frequency of the electronic expansion valve as the pulse period; and using the result of multiplying the pulse period by a set duty cycle as the energizing time of the electronic expansion valve.

[0090] When controlling the energizing time of the electronic expansion valve, the host computer first sets the operating frequency f of the electronic expansion valve and calculates the conduction time based on the operating frequency f. The conduction time T = (1 / f) * duty cycle, and the duty cycle is set according to the actual situation. Then, based on the conduction time T, a pulse control method is used to control the conduction time of each phase coil in the electronic expansion valve. Figure 5 As shown in (b), taking the first pulse as an example, phase A is energized only for a portion of the time, with a high level when energized and a low level when not energized. The electronic expansion valve operates normally when energized and does not operate when not energized. During this time, the coil does not generate heat and dissipates any accumulated heat.

[0091] ˉˉ

[0092] As long as the voltage between terminals A, B, and B is the same as that between terminals COM, it is equivalent to the coil being de-energized. For example, the coil can be de-energized if terminals OUT1 to OUT4 of the host computer control driver chip are all at a high level.

[0093] The pulse control method not only reduces the temperature at the electronic expansion valve, but also does not change the operating frequency of the electronic expansion valve.

[0094] Figure 7 This is a schematic diagram of a process for controlling the energization of an electronic expansion valve using a pulse method. The method includes:

[0095] Step 11: The host computer sets the operating frequency f of the electronic expansion valve and calculates the duty cycle time T = (1 / f) * duty cycle, where the duty cycle is the set value.

[0096] Step 12: The host computer sequentially controls the power supply to each phase of the electronic expansion valve via the control chip pins. After the power supply time reaches the duty cycle time, the control chip outputs a high level, thus de-energizing the electronic expansion valve.

[0097] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0098] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the valve's operating frequency. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to its operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the valve and preventing high-temperature failure. This effectively controls the temperature of the motor winding and ensures stable operation of the magnetic levitation motor.

[0099] According to an embodiment of the present invention, a magnetic levitation motor corresponding to a cooling device for a magnetic levitation motor is also provided. This magnetic levitation motor may include the cooling device for a magnetic levitation motor described above.

[0100] Since the processing and functions implemented by the magnetic levitation motor in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned device, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0101] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the valve's operating frequency. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to its operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the valve and preventing high-temperature failure. This effectively controls the temperature of the motor winding and ensures stable operation of the magnetic levitation motor.

[0102] According to an embodiment of the present invention, a storage medium corresponding to a cooling method for a magnetic levitation motor is also provided, the storage medium including a stored program, wherein, when the program is executed, the device where the storage medium is located controls the execution of the cooling method for the magnetic levitation motor described above.

[0103] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0104] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the valve's operating frequency. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to its operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the valve and preventing high-temperature failure. This effectively controls the temperature of the motor winding and ensures stable operation of the magnetic levitation motor.

[0105] According to an embodiment of the present invention, a computer program product corresponding to a cooling method for a magnetic levitation motor is also provided. The computer program product includes a computer program that, when processed and executed, implements the steps of the cooling method for the magnetic levitation motor described above.

[0106] Since the processing and functions implemented by the computer program product in this embodiment are basically corresponding to the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0107] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipe of the motor winding to control the coolant flow rate. After the magnetic levitation motor starts working, the target opening degree of the electronic expansion valve is determined based on the temperature of the motor winding. The electronic expansion valve is energized using a pulse method, and the energizing time is controlled according to the valve's operating frequency. This reduces the energizing time of the electronic expansion valve while achieving the target opening degree, thereby lowering the heat at the valve. By using a pulse method to energize the electronic expansion valve and controlling the energizing time according to its operating frequency, the energizing time of the electronic expansion valve is reduced, lowering the heat at the valve and preventing high-temperature failure. This effectively controls the temperature of the motor winding and ensures stable operation of the magnetic levitation motor.

[0108] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0109] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A cooling method for a magnetic levitation motor, characterized in that, A coolant pipe is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipe; The method includes: After the magnetic levitation motor starts working, the temperature of the motor windings and the operating frequency of the electronic expansion valve are obtained; The target opening degree of the electronic expansion valve is determined based on the temperature of the motor windings. The electronic expansion valve is energized using a pulse method, and the energizing time of the electronic expansion valve is controlled according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve and reduce the heat at the electronic expansion valve while making the opening degree of the electronic expansion valve reach the target opening degree. Determining the target opening degree of the electronic expansion valve based on the temperature of the motor windings includes: The temperature of the motor windings is incorporated into a preset calculation formula to calculate the target opening of the electronic expansion valve; the preset calculation formula is: IN pre-sat =U p (k)+U i (k); Among them, U pre-sat U represents the target opening degree of the electronic expansion valve. p (k) represents the proportional output, U p (k)= K p err(k), err(k) = -(Ref - Fdb), where Fdb is the temperature of the motor winding, Ref is the reference temperature of the motor winding, and K p U is the proportional gain coefficient; i (k) represents the integral output.

2. The cooling method for the magnetic levitation motor according to claim 1, characterized in that, The electronic expansion valve has a four-phase coil and a valve body; by controlling the energization of each phase coil in the four-phase coil according to the set energization sequence, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

3. The cooling method for the magnetic levitation motor according to claim 1 or 2, characterized in that, Controlling the energizing time of the electronic expansion valve according to its operating frequency includes: The reciprocal of the operating frequency of the electronic expansion valve is determined as the pulse period; The result of multiplying the pulse period by the set duty cycle is used as the energizing time of the electronic expansion valve.

4. A cooling device for a magnetic levitation motor, characterized in that, A coolant pipe is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipe; The cooling device includes: The acquisition unit is configured to acquire the temperature of the motor windings and the operating frequency of the electronic expansion valve after the magnetic levitation motor starts working; The control unit is configured to determine the target opening degree of the electronic expansion valve based on the temperature of the motor windings; The control unit is further configured to energize the electronic expansion valve in a pulse manner and control the energizing time of the electronic expansion valve according to the operating frequency of the electronic expansion valve, so as to reduce the energizing time of the electronic expansion valve and reduce the heat at the electronic expansion valve while making the opening degree of the electronic expansion valve reach the target opening degree. The control unit determines the target opening degree of the electronic expansion valve based on the temperature of the motor windings, including: The temperature of the motor windings is incorporated into a preset calculation formula to calculate the target opening of the electronic expansion valve; the preset calculation formula is: IN pre-sat =U p (k)+U i (k); Among them, U pre-sat U represents the target opening degree of the electronic expansion valve. p (k) represents the proportional output, U p (k)= K p err(k), err(k) = -(Ref - Fdb), where Fdb is the temperature of the motor winding, Ref is the reference temperature of the motor winding, and K p U is the proportional gain coefficient; i (k) represents the integral output.

5. The cooling device for the magnetic levitation motor according to claim 4, characterized in that, The electronic expansion valve has a four-phase coil and a valve body; by controlling the energization of each phase coil in the four-phase coil according to the set energization sequence, the valve body is activated to change the opening degree of the electronic expansion valve, so that the electronic expansion valve reaches the target opening degree.

6. A magnetic levitation motor, characterized in that, include: The cooling device for the magnetic levitation motor as described in claim 4 or 5.

7. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the cooling method of the magnetic levitation motor according to any one of claims 1 to 3.

8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 3.

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