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: according to the temperature of motor winding and the reference temperature of motor winding, determine whether the opening of electronic expansion valve is adjusted;If it is determined that the opening of electronic expansion valve is adjusted, the temperature of motor winding and the reference temperature of motor winding are brought into the preset anti-saturation PI algorithm, and the opening calculation value of electronic expansion valve is obtained;The opening of electronic expansion valve is controlled to be opening calculation value.The scheme, by setting electronic expansion valve control coolant flow, according to the anti-saturation PI algorithm control electronic expansion valve opening, prevent electronic expansion valve from being in saturation state, improve the sensitivity of electronic expansion valve opening adjustment and the accuracy of motor winding temperature control.

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 the motor windings, the coolant flow rate needs to be controlled. Insufficient coolant will cause the motor winding temperature to be too high, which will affect the motor's lifespan over time. Excessive coolant will not only cause the motor winding temperature to be too low, but will also cause condensation on the motor housing. Since magnetic levitation motors require a controller to control the bearing levitation, the controller must be installed on the motor housing. If condensation occurs on the motor and enters the controller, it will pose a short circuit risk to the motor bearing levitation controller.

[0004] The existing solutions control coolant flow by installing a solenoid valve between the coolant pipe and the motor winding cooling channel. The flow rate is controlled by adjusting the solenoid valve's on / off state. However, this method cannot precisely control the cooling flow rate, and there is still a possibility of insufficient or excessive coolant, causing significant temperature fluctuations in the motor windings. This leads to frequent solenoid valve operation, greatly reducing its lifespan.

[0005] 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

[0006] 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, in order to solve the problem that the solenoid valve on the coolant pipeline of the magnetic levitation motor cannot accurately control the coolant flow rate in related solutions. This invention achieves the effect of controlling the coolant flow rate by setting an electronic expansion valve, controlling the opening degree of the electronic expansion valve according to an anti-saturation PI algorithm, preventing the electronic expansion valve from being in a saturated state, and improving the sensitivity of the opening degree adjustment and the accuracy of the motor winding temperature control.

[0007] 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: acquiring the temperature of the motor winding and a reference temperature of the motor winding; determining whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and the reference temperature of the motor winding; if it is determined that the opening of the electronic expansion valve should be adjusted, then the temperature of the motor winding and the reference temperature of the motor winding are input into a preset anti-saturation PI algorithm to obtain a calculated value of the opening of the electronic expansion valve; and controlling the opening of the electronic expansion valve to be the calculated value.

[0008] In some embodiments, determining whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and the reference temperature of the motor winding includes: recording the difference between the reference temperature of the motor winding and the temperature of the motor winding as the actual temperature difference; determining the relationship between the actual temperature difference and a preset temperature difference; if the actual temperature difference is greater than the preset temperature difference, determining to adjust the opening of the electronic expansion valve; if the actual temperature difference is less than or equal to the preset temperature difference, determining not to adjust the opening of the electronic expansion valve.

[0009] In some embodiments, after determining to adjust the opening of the electronic expansion valve, the relationship between the temperature of the motor winding and the reference temperature of the motor winding is determined. If the temperature of the motor winding is greater than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset maximum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is less than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset minimum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is equal to the reference temperature of the electronic expansion valve, then the opening of the electronic expansion valve is not adjusted.

[0010] In some implementations, the temperature of the motor winding and a reference temperature of the motor winding are input into a preset anti-saturation PI algorithm to obtain the calculated opening value of the electronic expansion valve, including:

[0011] The temperature of the motor winding and its reference temperature are input into a preset anti-saturation PI algorithm to calculate the pre-output opening of the electronic expansion valve. The formula for the preset anti-saturation PI algorithm is as follows:

[0012] U pre-sat =U p (k)+U i (k);

[0013] The pre-output opening of the electronic expansion valve is limited to obtain the calculated opening value of the electronic expansion valve. The formula for limiting the pre-output opening of the electronic expansion valve is as follows:

[0014]

[0015] Among them, U pre-sat U(k) represents the pre-output opening of the electronic expansion valve, and U(k) represents the calculated opening value of the electronic expansion valve. max U is the maximum opening degree of the electronic expansion valve. min U represents the minimum opening degree of the electronic expansion valve. i (k) represents the integral output; U p (k) represents the proportional output, U p (k)=K p err(k), err(k)=-(Ref-Fdb), K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, and Fdb is the temperature of the motor winding.

[0016] 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 a reference temperature of the motor winding; a control unit configured to determine whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and the reference temperature of the motor winding; the control unit is further configured to, if it is determined that the opening of the electronic expansion valve should be adjusted, input the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain a calculated value for the opening of the electronic expansion valve; the control unit is further configured to control the opening of the electronic expansion valve to be the calculated value.

[0017] In some embodiments, the control unit determines whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and a reference temperature of the motor winding, including: recording the difference between the reference temperature of the motor winding and the temperature of the motor winding as the actual temperature difference; determining the relationship between the actual temperature difference and a preset temperature difference; if the actual temperature difference is greater than the preset temperature difference, determining to adjust the opening of the electronic expansion valve; if the actual temperature difference is less than or equal to the preset temperature difference, determining not to adjust the opening of the electronic expansion valve.

[0018] In some embodiments, after determining to adjust the opening of the electronic expansion valve, the control unit determines the relationship between the temperature of the motor winding and the reference temperature of the motor winding; if the temperature of the motor winding is greater than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not at the preset maximum opening, then it determines to adjust the opening of the electronic expansion valve; if the temperature of the motor winding is less than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not at the preset minimum opening, then it determines to adjust the opening of the electronic expansion valve; if the temperature of the motor winding is equal to the reference temperature of the electronic expansion valve, then it determines not to adjust the opening of the electronic expansion valve.

[0019] In some embodiments, the control unit inputs the temperature of the motor winding and a reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the calculated opening value of the electronic expansion valve, including:

[0020] The temperature of the motor winding and its reference temperature are input into a preset anti-saturation PI algorithm to obtain the pre-output opening of the electronic expansion valve. The formula for the preset anti-saturation PI algorithm is as follows:

[0021] U pre-sat =U p (k)+U i (k);

[0022] The pre-output opening of the electronic expansion valve is limited to obtain the calculated opening value of the electronic expansion valve. The formula for limiting the pre-output opening of the electronic expansion valve is as follows:

[0023]

[0024] Among them, U pre-sat U(k) represents the pre-output opening of the electronic expansion valve, and U(k) represents the calculated opening value of the electronic expansion valve. max U is the maximum opening degree of the electronic expansion valve. min U represents the minimum opening degree of the electronic expansion valve. i (k) represents the integral output; U p (k) represents the proportional output, U p (k)=K p err(k), err(k)=-(Ref-Fdb), K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, and Fdb is the temperature of the motor winding.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The present invention involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting the valve opening using the anti-saturation PI algorithm, the saturation state of the electronic expansion valve is prevented, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0029] 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.

[0030] 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

[0031] Figure 1 This is a schematic flowchart of an embodiment of the cooling method for the magnetic levitation motor of the present invention;

[0032] 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;

[0033] Figure 3 This is a schematic diagram of the motor winding cooling pipes.

[0034] Figure 4 This is a schematic diagram showing the wiring method and valve opening / closing method of an electronic expansion valve;

[0035] Figure 5 This is a schematic diagram of a PI controller;

[0036] Figure 6 A schematic diagram of the temperature control process for motor windings;

[0037] Figure 7This is a flowchart illustrating the anti-saturation PI algorithm.

[0038] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0039] 102 - Acquisition unit; 104 - Control unit. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] Wiring of the electronic expansion valve 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.

[0043] The electronic expansion valve is controlled by a four-wire, eight-step control method, such as... Figure 4 As shown in (c), during the control process, one or two phases are always kept energized. The shaded area in the figure indicates that the phase is in an energized state.

[0044] like Figure 1The 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 S140.

[0045] In step S110, the temperature of the motor winding and the reference temperature of the motor winding are obtained.

[0046] In step S120, based on the temperature of the motor winding and the reference temperature of the motor winding, it is determined whether to adjust the opening of the electronic expansion valve.

[0047] In some embodiments, step S120, the specific process of determining whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and the reference temperature of the motor winding, includes: recording the difference between the reference temperature of the motor winding and the temperature of the motor winding as the actual temperature difference; determining the relationship between the actual temperature difference and the preset temperature difference; if the actual temperature difference is greater than the preset temperature difference, then determining to adjust the opening of the electronic expansion valve; if the actual temperature difference is less than or equal to the preset temperature difference, then determining not to adjust the opening of the electronic expansion valve.

[0048] The preset temperature difference is the difference between the reference temperature and the actual temperature of the motor windings when the electronic expansion valve opening was last adjusted. Each adjustment of the electronic expansion valve constitutes one cycle, and the reference temperature of the motor windings may differ in each cycle. The reference temperature can be considered the target temperature of the motor windings; a larger temperature difference between the reference and current temperatures indicates that the motor winding temperature deviates too much from the target temperature. If the temperature difference gradually increases, it indicates that the current electronic expansion valve opening is inappropriate, resulting in excessively high or low coolant flow. In this case, the opening of the electronic expansion valve needs to be adjusted. Specifically, if the temperature difference fab2 between the motor winding temperature and the reference temperature in the previous cycle is less than the temperature difference fab1 in the current cycle, it indicates that the motor winding temperature is gradually deviating from the reference temperature, and the electronic expansion valve opening is too large or too small. In this case, the opening of the electronic expansion valve needs to be adjusted to bring the motor winding temperature closer to the reference temperature. If fab2 ≥ fab1, it indicates that the motor winding temperature is gradually approaching the reference temperature, and the current electronic expansion valve opening is appropriate. In this case, it is not necessary to adjust the opening of the electronic expansion valve.

[0049] By repeatedly adjusting the opening of the electronic expansion valve, the temperature of the motor windings can be brought to a suitable range more quickly. Afterward, the opening of the electronic expansion valve will also be within a certain range, so that the temperature of the motor windings can be stabilized within a suitable range, achieving the effect of fast and precise control of the motor winding temperature.

[0050] In step S130, if it is determined that the opening of the electronic expansion valve is to be adjusted, the temperature of the motor winding and the reference temperature of the motor winding are input into the preset anti-saturation PI algorithm to obtain the calculated value of the opening of the electronic expansion valve.

[0051] In some embodiments, after determining to adjust the opening of the electronic expansion valve based on the temperature and reference temperature of the motor windings, the process further includes predicting whether the adjusted electronic expansion valve is in a saturated state, and then determining whether to adjust the opening of the electronic expansion valve. This process specifically includes: after determining to adjust the opening of the electronic expansion valve, determining the relationship between the temperature of the motor windings and the reference temperature of the motor windings; if the temperature of the motor windings is greater than the reference temperature of the motor windings, and the opening of the electronic expansion valve is not at the preset maximum opening, then determining to adjust the opening of the electronic expansion valve; if the temperature of the motor windings is less than the reference temperature of the motor windings, and the opening of the electronic expansion valve is not at the preset minimum opening, then determining to adjust the opening of the electronic expansion valve; if the temperature of the motor windings is equal to the reference temperature of the electronic expansion valve, then determining not to adjust the opening of the electronic expansion valve.

[0052] To avoid the electronic expansion valve becoming saturated after adjusting its opening, before adjustment, it's first determined whether PI adjustment will lead to saturation based on the current opening and adjustment trend of the electronic expansion valve, thus deciding whether to perform PI algorithm adjustment. Specifically, when the motor winding temperature Fdb > the motor winding reference temperature Ref, it indicates that the motor winding temperature is high, requiring an increase in the electronic expansion valve opening to cool the motor winding. If the electronic expansion valve is already at its maximum opening, the opening value calculated by the PI algorithm will inevitably exceed the maximum opening, causing the electronic expansion valve to saturate. Therefore, in this case, the PI algorithm is not used to adjust the electronic expansion valve opening, and the electronic expansion valve remains at its current opening. When Fdb < Ref, it indicates that the motor winding temperature is low, requiring a decrease in the electronic expansion valve opening to heat the motor winding. If the electronic expansion valve is already at its minimum opening, the opening value calculated by the PI algorithm will inevitably be less than the minimum opening. Therefore, in this case, the PI algorithm is not used to adjust the electronic expansion valve opening, and the electronic expansion valve remains at its current opening. When Fdb = Ref, it means that the temperature of the motor winding is within a suitable range, and there is no need to adjust the opening of the electronic expansion valve.

[0053] Figure 6 This is a flowchart illustrating the temperature control process for motor windings, as shown below. Figure 6 As shown, the method includes:

[0054] Step 1: Set the motor winding reference temperature Ref, obtain the motor winding temperature feedback value Fdb, and calculate the absolute value of the difference fabs1 = fabs(Ref - Fdb). fabs2 is the absolute value of the difference between the reference temperature and the temperature feedback value in the previous cycle. Determine if fabs1 - fabs2 > 0. If fabs1 - fabs2 > 0, proceed to Step 2; if fabs1 - fabs2 ≤ 0, keep the opening of the electronic expansion valve unchanged.

[0055] Step 2: Calculate the error err1 = -(Ref - Fdb), and determine whether err1 < 0 and the current electronic expansion valve opening U(k) = minimum opening U. min . If err1<0 and U(k)=U min If the opening of the electronic expansion valve remains unchanged, proceed to step 3; otherwise, proceed to step 3.

[0056] Step 3: Determine if err1 > 0 and U(k) = maximum opening U. max . If err1>0 and U(k)=U max If the opening of the electronic expansion valve remains unchanged, then the opening of the electronic expansion valve is calculated according to the PI control algorithm. The electronic expansion valve is adjusted according to the calculated value, and the absolute value fabs2 = fabs1 is saved.

[0057] The PI algorithm can calculate the required opening degree of the electronic expansion valve based on the temperature of the motor windings and a reference temperature. Its control block diagram is shown below. Figure 5 As shown, the algorithm's inputs are the reference temperature Ref and the motor winding Fdb, and the output is the electronic expansion valve opening U. pre-sat The specific formula for the PI algorithm is as follows:

[0058] U pre-sat (t)=U p (t)+U i (t);

[0059] Where, the error e(t) = -(Ref - Fdb), and the proportional term U p (t)=K p e(t), the integral term K p T is the proportional gain coefficient. i This is the integral time of the PI controller.

[0060] In some embodiments, step S130, which involves inputting the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the calculated opening value of the electronic expansion valve, includes steps S210 and S220.

[0061] Step S210: Input the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the pre-output opening of the electronic expansion valve, as shown in the formula:

[0062] U pre-sat =U p (k)+U i (k).

[0063] Step S220: Limit the pre-output opening of the electronic expansion valve to obtain the calculated opening value of the electronic expansion valve, using the following formula:

[0064]

[0065] In the formula, U pre-sat U(k) represents the pre-output opening of the electronic expansion valve, and U(k) represents the calculated opening value of the electronic expansion valve. max U is the maximum opening degree of the electronic expansion valve. min U represents the minimum opening degree of the electronic expansion valve. i (k) is the integral output, U i (k)=U i (k-1)+K i U p (k); K i For integral control gain, the default is... 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, and Fdb is the temperature of the motor winding.

[0066] By controlling the opening of the electronic expansion valve according to an anti-saturation PI algorithm, the opening of the electronic expansion valve increases when the motor winding temperature is higher than the reference temperature, and decreases when the motor winding temperature is lower than the reference temperature. The greater the temperature difference, the larger the opening adjustment. Furthermore, 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, making the opening adjustment more sensitive, the motor winding temperature control more precise, and avoiding excessively high temperatures that could affect motor lifespan, and excessively low temperatures that could cause condensation and short circuits.

[0067] Figure 7 The flowchart of the anti-saturation PI algorithm is shown below. Figure 7 As shown, the method includes:

[0068] Step 11: Obtain the current temperature Fdb and reference temperature Ref of the motor winding, and calculate the error err(k) = -(Ref - Fdb).

[0069] Step 12, calculate the proportional output, U p (k)=K p err(k), K p This is the proportional gain coefficient.

[0070] Step 13, calculate the integral output, U i (k)=U i (k-1)+K i U p (k), default

[0071] Step 14, calculate the pre-output opening value, U pre-sat =U p (k)+U i (k).

[0072] Step 15: Limit the pre-output opening value:

[0073]

[0074] Among them, U max This is the maximum opening of the electronic expansion valve, default 500; U min This is the minimum opening degree of the electronic expansion valve; the default value is 0.

[0075] In step S140, the opening degree of the electronic expansion valve is controlled to be the calculated opening degree value.

[0076] By controlling the opening of the electronic expansion valve using an anti-saturation PI controller, it is possible to prevent the electronic expansion valve from being in an oversaturated or undersaturated state, making the opening adjustment more sensitive and the temperature control of the motor windings more precise.

[0077] The technical solution of this embodiment involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting its opening according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from becoming saturated, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0078] 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.

[0079] Wiring of the electronic expansion valve 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.

[0080] The electronic expansion valve is controlled by a four-wire, eight-step control method, such as... Figure 4 As shown in (c), during the control process, one or two phases are always kept energized. The shaded area in the figure indicates that the phase is in an energized state.

[0081] 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.

[0082] The acquisition unit 102 is configured to acquire the temperature of the motor winding and a reference temperature of the motor winding. For the specific functions and processing of the acquisition unit 102, please refer to step S110.

[0083] Control unit 104 is configured to determine whether to adjust the opening of the electronic expansion valve based on the temperature of the motor windings and a reference temperature of the motor windings. The specific functions and processing of this control unit 104 are described in step S120.

[0084] In some embodiments, the control unit 104 determines whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and the reference temperature of the motor winding, including: recording the difference between the reference temperature of the motor winding and the temperature of the motor winding as the actual temperature difference; determining the relationship between the actual temperature difference and a preset temperature difference; if the actual temperature difference is greater than the preset temperature difference, determining to adjust the opening of the electronic expansion valve; if the actual temperature difference is less than or equal to the preset temperature difference, determining not to adjust the opening of the electronic expansion valve.

[0085] The preset temperature difference is the difference between the reference temperature and the actual temperature of the motor windings when the electronic expansion valve opening was last adjusted. Each adjustment of the electronic expansion valve constitutes one cycle, and the reference temperature of the motor windings may differ in each cycle. The reference temperature can be considered the target temperature of the motor windings; a larger temperature difference between the reference and current temperatures indicates that the motor winding temperature deviates too much from the target temperature. If the temperature difference gradually increases, it indicates that the current electronic expansion valve opening is inappropriate, resulting in excessively high or low coolant flow. In this case, the opening of the electronic expansion valve needs to be adjusted. Specifically, if the temperature difference fab2 between the motor winding temperature and the reference temperature in the previous cycle is less than the temperature difference fab1 in the current cycle, it indicates that the motor winding temperature is gradually deviating from the reference temperature, and the electronic expansion valve opening is too large or too small. In this case, the opening of the electronic expansion valve needs to be adjusted to bring the motor winding temperature closer to the reference temperature. If fab2 ≥ fab1, it indicates that the motor winding temperature is gradually approaching the reference temperature, and the current electronic expansion valve opening is appropriate. In this case, it is not necessary to adjust the opening of the electronic expansion valve.

[0086] By repeatedly adjusting the opening of the electronic expansion valve, the temperature of the motor windings can be brought to a suitable range more quickly. Afterward, the opening of the electronic expansion valve will also be within a certain range, so that the temperature of the motor windings can be stabilized within a suitable range, achieving the effect of fast and precise control of the motor winding temperature.

[0087] The control unit 104 is further configured to, if it is determined that the opening degree of the electronic expansion valve needs to be adjusted, input the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the calculated opening degree of the electronic expansion valve. The specific functions and processing of this control unit 104 are described in step S130.

[0088] In some embodiments, after determining to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and a reference temperature of the motor winding, the control unit 104 further includes predicting whether the adjusted electronic expansion valve is in a saturated state, and further determining whether to adjust the opening of the electronic expansion valve. Specifically, after determining to adjust the opening of the electronic expansion valve, it determines the relationship between the temperature of the motor winding and the reference temperature of the motor winding; if the temperature of the motor winding is greater than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset maximum opening, then it determines to adjust the opening of the electronic expansion valve; if the temperature of the motor winding is less than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset minimum opening, then it determines to adjust the opening of the electronic expansion valve; if the temperature of the motor winding is equal to the reference temperature of the electronic expansion valve, then it determines not to adjust the opening of the electronic expansion valve.

[0089] To avoid the electronic expansion valve becoming saturated after adjusting its opening, before adjustment, it's first determined whether PI adjustment will lead to saturation based on the current opening and adjustment trend of the electronic expansion valve, thus deciding whether to perform PI algorithm adjustment. Specifically, when the motor winding temperature Fdb > the motor winding reference temperature Ref, it indicates that the motor winding temperature is high, requiring an increase in the electronic expansion valve opening to cool the motor winding. If the electronic expansion valve is already at its maximum opening, the opening value calculated by the PI algorithm will inevitably exceed the maximum opening, causing the electronic expansion valve to saturate. Therefore, in this case, the PI algorithm is not used to adjust the electronic expansion valve opening, and the electronic expansion valve remains at its current opening. When Fdb < Ref, it indicates that the motor winding temperature is low, requiring a decrease in the electronic expansion valve opening to heat the motor winding. If the electronic expansion valve is already at its minimum opening, the opening value calculated by the PI algorithm will inevitably be less than the minimum opening. Therefore, in this case, the PI algorithm is not used to adjust the electronic expansion valve opening, and the electronic expansion valve remains at its current opening. When Fdb = Ref, it means that the temperature of the motor winding is within a suitable range, and there is no need to adjust the opening of the electronic expansion valve.

[0090] Figure 6 This is a flowchart illustrating the temperature control process for motor windings, as shown below. Figure 6 As shown, the method includes:

[0091] Step 1: Set the motor winding reference temperature Ref, obtain the motor winding temperature feedback value Fdb, and calculate the absolute value of the difference fabs1 = fabs(Ref - Fdb). fabs2 is the absolute value of the difference between the reference temperature and the temperature feedback value in the previous cycle. Determine if fabs1 - fabs2 > 0. If fabs1 - fabs2 > 0, proceed to Step 2; if fabs1 - fabs2 ≤ 0, keep the opening of the electronic expansion valve unchanged.

[0092] Step 2: Calculate the error err1 = -(Ref - Fdb), and determine whether err1 < 0 and the current electronic expansion valve opening U(k) = minimum opening U. min . If err1<0 and U(k)=U min If the opening of the electronic expansion valve remains unchanged, proceed to step 3; otherwise, proceed to step 3.

[0093] Step 3: Determine if err1 > 0 and U(k) = maximum opening U. max . If err1>0 and U(k)=U max If the opening of the electronic expansion valve remains unchanged, then the opening of the electronic expansion valve is calculated according to the PI control algorithm. The electronic expansion valve is adjusted according to the calculated value, and the absolute value fabs2 = fabs1 is saved.

[0094] The PI algorithm can calculate the required opening degree of the electronic expansion valve based on the temperature of the motor windings and a reference temperature. Its control block diagram is shown below. Figure 5 As shown, the algorithm's inputs are the reference temperature Ref and the motor winding Fdb, and the output is the electronic expansion valve opening U. pre-sat The specific formula for the PI algorithm is as follows:

[0095] U pre-sat (t)=U p (t)+U i (t);

[0096] Where, the error e(t) = -(Ref - Fdb), and the proportional term U p (t)=K p e(t), the integral term K p T is the proportional gain coefficient. i This is the integral time of the PI controller.

[0097] In some embodiments, the control unit 104 inputs the temperature of the motor winding and a reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the calculated opening value of the electronic expansion valve, including:

[0098] The control unit 104 is further configured to input the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain the pre-output opening of the electronic expansion valve, as shown in the formula:

[0099] U pre-sat =U p (k)+U i (k).

[0100] The control unit 104 is further configured to limit the pre-output opening of the electronic expansion valve to obtain a calculated opening value of the electronic expansion valve, using the following formula:

[0101]

[0102] In the formula, U pre-sat U(k) represents the pre-output opening of the electronic expansion valve, and U(k) represents the calculated opening value of the electronic expansion valve. max U is the maximum opening degree of the electronic expansion valve. min U represents the minimum opening degree of the electronic expansion valve. i (k) is the integral output, U i (k)=U i (k-1)+K i U p (k); K i For integral control gain, the default is... 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, and Fdb is the temperature of the motor winding.

[0103] By controlling the opening of the electronic expansion valve according to an anti-saturation PI algorithm, the opening of the electronic expansion valve increases when the motor winding temperature is higher than the reference temperature, and decreases when the motor winding temperature is lower than the reference temperature. The greater the temperature difference, the larger the opening adjustment. Furthermore, 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, making the opening adjustment more sensitive, the motor winding temperature control more precise, and avoiding excessively high temperatures that could affect motor lifespan, and excessively low temperatures that could cause condensation and short circuits.

[0104] Figure 7 The flowchart of the anti-saturation PI algorithm is shown below. Figure 7 As shown, the method includes:

[0105] Step 11: Obtain the current temperature Fdb and reference temperature Ref of the motor winding, and calculate the error err(k) = -(Ref - Fdb).

[0106] Step 12, calculate the proportional output, U p (k)=K p err(k), K p This is the proportional gain coefficient.

[0107] Step 13, calculate the integral output, U i (k)=U i (k-1)+K i U p (k), default

[0108] Step 14, calculate the pre-output opening value, U pre-sat =U p (k)+U i (k).

[0109] Step 15: Limit the pre-output opening value:

[0110]

[0111] Among them, U max This is the maximum opening of the electronic expansion valve, default 500; U min This is the minimum opening degree of the electronic expansion valve; the default value is 0.

[0112] The control unit 104 is also configured to control the opening degree of the electronic expansion valve to the calculated opening degree value. For the specific functions and processing of the control unit 104, please refer to step S140.

[0113] By controlling the opening of the electronic expansion valve using an anti-saturation PI controller, it is possible to prevent the electronic expansion valve from being in an oversaturated or undersaturated state, making the opening adjustment more sensitive and the temperature control of the motor windings more precise.

[0114] 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.

[0115] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting its opening according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from becoming saturated, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0116] 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.

[0117] 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.

[0118] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting its opening according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from becoming saturated, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0119] 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.

[0120] 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.

[0121] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting its opening according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from becoming saturated, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0122] 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.

[0123] 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.

[0124] The technical solution of this invention involves installing an electronic expansion valve on the coolant pipeline of the motor winding to control the coolant flow rate. The opening degree of the electronic expansion valve is adjusted based on the temperature and reference temperature of the motor winding. If adjustment is determined, the motor winding temperature and reference temperature are input into an anti-saturation PI algorithm to obtain a calculated value for the electronic expansion valve opening, which is then controlled to match this calculated value. By controlling the coolant flow rate with an electronic expansion valve and adjusting its opening according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from becoming saturated, thus improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0125] 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.

[0126] 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: Obtain the temperature of the motor windings and the reference temperature of the motor windings; Based on the temperature of the motor windings and the reference temperature of the motor windings, determine whether to adjust the opening of the electronic expansion valve; If it is determined that the opening degree of the electronic expansion valve needs to be adjusted, then the temperature of the motor winding and the reference temperature of the motor winding are input into a preset anti-saturation PI algorithm to obtain the calculated value of the opening degree of the electronic expansion valve; the formula of the preset anti-saturation PI algorithm is: IN pre-sat =U p (k)+U i (k); Among them, U pre-sat U represents the pre-output opening of the electronic expansion valve. i (k) represents the integral output; U p (k) represents the proportional output, U p (k)= K p err(k), err(k)= -(Ref-Fdb), K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, and Fdb is the temperature of the motor winding; The opening degree of the electronic expansion valve is controlled to be the calculated opening degree value.

2. The cooling method for the magnetic levitation motor according to claim 1, characterized in that, Based on the temperature of the motor windings and a reference temperature of the motor windings, determine whether to adjust the opening of the electronic expansion valve, including: The difference between the reference temperature of the motor winding and the temperature of the motor winding is recorded as the actual temperature difference; Determine the relationship between the actual temperature difference and the preset temperature difference; If the actual temperature difference is greater than the preset temperature difference, then the opening of the electronic expansion valve is adjusted. If the actual temperature difference is less than or equal to the preset temperature difference, then the opening of the electronic expansion valve will not be adjusted.

3. The cooling method for the magnetic levitation motor according to claim 1 or 2, characterized in that, Also includes: After determining that the opening of the electronic expansion valve should be adjusted, the relationship between the temperature of the motor winding and the reference temperature of the motor winding is determined. If the temperature of the motor winding is greater than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset maximum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is lower than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset minimum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is equal to the reference temperature of the electronic expansion valve, then it is determined that the opening of the electronic expansion valve will not be adjusted.

4. The cooling method for the magnetic levitation motor according to claim 1, characterized in that, The temperature of the motor winding and its reference temperature are input into a preset anti-saturation PI algorithm to obtain the calculated opening value of the electronic expansion valve, including: The temperature of the motor winding and the reference temperature of the motor winding are input into a preset anti-saturation PI algorithm to calculate the pre-output opening of the electronic expansion valve. The pre-output opening of the electronic expansion valve is limited to obtain the calculated opening value of the electronic expansion valve. The formula for limiting the pre-output opening of the electronic expansion valve is as follows: ； Wherein, U(k) is the calculated opening value of the electronic expansion valve, U max U represents the maximum opening degree of the electronic expansion valve. min This is the minimum opening degree of the electronic expansion valve.

5. 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 winding and the reference temperature of the motor winding; The control unit is configured to determine whether to adjust the opening of the electronic expansion valve based on the temperature of the motor winding and a reference temperature of the motor winding. The control unit is further configured to, if it is determined that the opening degree of the electronic expansion valve needs to be adjusted, input the temperature of the motor winding and the reference temperature of the motor winding into a preset anti-saturation PI algorithm to obtain a calculated value for the opening degree of the electronic expansion valve; the formula for the preset anti-saturation PI algorithm is: IN pre-sat =U p (k)+U i (k); Among them, U pre-sat U represents the pre-output opening of the electronic expansion valve. i (k) represents the integral output; U p (k) represents the proportional output, U p (k)= K p err(k), err(k)= -(Ref-Fdb), K p is the proportional gain coefficient; Ref is the reference temperature of the motor winding, and Fdb is the temperature of the motor winding; The control unit is also configured to control the opening degree of the electronic expansion valve to the calculated opening degree value.

6. The cooling device for the magnetic levitation motor according to claim 5, characterized in that, The control unit determines whether to adjust the opening of the electronic expansion valve based on the temperature of the motor windings and a reference temperature of the motor windings, including: The difference between the reference temperature of the motor winding and the temperature of the motor winding is recorded as the actual temperature difference; Determine the relationship between the actual temperature difference and the preset temperature difference; If the actual temperature difference is greater than the preset temperature difference, then the opening of the electronic expansion valve is adjusted. If the actual temperature difference is less than or equal to the preset temperature difference, then the opening of the electronic expansion valve will not be adjusted.

7. The cooling device for the magnetic levitation motor according to claim 5 or 6, characterized in that, The control unit further includes: After determining that the opening of the electronic expansion valve should be adjusted, the relationship between the temperature of the motor winding and the reference temperature of the motor winding is determined. If the temperature of the motor winding is greater than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset maximum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is lower than the reference temperature of the motor winding, and the opening of the electronic expansion valve is not the preset minimum opening, then the opening of the electronic expansion valve is adjusted. If the temperature of the motor winding is equal to the reference temperature of the electronic expansion valve, then it is determined that the opening of the electronic expansion valve will not be adjusted.

8. A magnetic levitation motor, characterized in that, include: The cooling device for the magnetic levitation motor as described in any one of claims 5 to 7.

9. 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 4.

10. 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 4.

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