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

Abstract

The invention discloses a cooling method and device of a magnetic suspension motor, the magnetic suspension motor, a storage medium and a computer program product, a coolant pipeline is arranged at a motor winding of the magnetic suspension motor, and an electronic expansion valve is arranged on the coolant pipeline; the method comprises the steps that whether the opening degree of the electronic expansion valve is adjusted or not is determined according to the temperature of a motor winding and the reference temperature of the motor winding; if it is determined that the opening degree of the electronic expansion valve is adjusted, the temperature of the motor winding and the reference temperature of the motor winding are substituted into a preset anti-saturation PI algorithm, and an opening degree calculated value of the electronic expansion valve is obtained; and controlling the opening degree of the electronic expansion valve to be the opening degree calculation value. According to the scheme, the coolant flow is controlled by arranging the electronic expansion valve, the opening degree of the electronic expansion valve is controlled according to the anti-saturation PI algorithm, the electronic expansion valve is prevented from being in a saturation state, and the sensitivity of opening degree adjustment of the electronic expansion valve and the accuracy of motor winding temperature control are improved.

Description

Technical Field

[0001] The present invention belongs to the field of magnetic levitation motors, and in particular relates to a cooling method and device for a magnetic levitation motor, a magnetic levitation motor, a storage medium and a computer program product. Background Art

[0002] During the operation of the magnetic levitation motor, the motor winding will generate a lot of heat due to the movement of the rotor cutting the magnetic flux lines, and coolant is needed to cool the motor winding.

[0003] When cooling the motor windings, the coolant flow needs to be controlled. Too little coolant will cause the motor winding temperature to be too high, and long-term operation will affect the motor life. Too much coolant will not only cause the motor winding temperature to be too low, but will also cause condensation on the motor housing. Since the magnetic levitation motor requires a controller to control the bearing suspension, the controller must be installed on the motor housing. If condensation is generated on the motor and enters the controller, it will cause the motor bearing suspension controller to short-circuit.

[0004] The method of controlling the coolant flow in the related scheme is to install a solenoid valve between the coolant pipeline and the motor winding cooling channel, and control the coolant flow by controlling the on / off state of the solenoid valve. However, this method cannot accurately control the cooling flow, and there may still be too little or too much coolant, causing the temperature of the motor winding to fluctuate greatly, and then the solenoid valve will frequently operate, greatly reducing the service life of the solenoid valve.

[0005] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The object of the present invention is to provide a cooling method and device for a magnetic levitation motor, a magnetic levitation motor, a storage medium and a computer program product, so as to solve the problem that the solenoid valve on the coolant pipeline of the magnetic levitation motor in the related scheme cannot accurately control the coolant flow rate, so as to achieve the effect of controlling the coolant flow rate by setting an electronic expansion valve, controlling the opening 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 adjustment and the accuracy of the motor winding temperature control.

[0007] The present invention provides a cooling method for a magnetic levitation motor, wherein a coolant pipeline is provided at a motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipeline; the method comprises: obtaining the temperature of the motor winding and the reference temperature of the motor winding; determining whether to adjust the opening of the electronic expansion valve according to 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 is to be adjusted, bringing 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 of the opening of the electronic expansion valve; and controlling the opening of the electronic expansion valve to be the calculated value of the opening.

[0008] In some embodiments, whether to adjust the opening of the electronic expansion valve is determined 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; judging the relationship between the actual temperature difference and the 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 a preset maximum opening at this time, it is determined 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 a preset minimum opening at this time, it is determined 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, it is determined not to adjust the opening of the electronic expansion valve.

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

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

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

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

[0014]

[0015] Among them, U pre-sat is the pre-output opening of the electronic expansion valve, U(k) is the calculated opening value of the electronic expansion valve, and U max is the maximum opening of the electronic expansion valve, U min is the minimum opening of the electronic expansion valve; U i (k) is the integral output; U p (k) is 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] Matching the above method, the present invention provides a cooling device for a magnetic levitation motor on the other hand, 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 comprises: an acquisition unit, configured to acquire the temperature of the motor winding and the reference temperature of the motor winding; a control unit, configured to determine whether to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding; the control unit is further configured to bring 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 of the opening of the electronic expansion valve if it is determined that the opening of the electronic expansion valve is to be adjusted; the control unit is further configured to control the opening of the electronic expansion valve to be the calculated value of the opening.

[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 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; judging the relationship between the actual temperature difference and the 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, the control unit, after determining to adjust the opening of the electronic expansion valve, 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 a preset maximum opening at this time, 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 a preset minimum opening at this time, 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, determines not to adjust the opening of the electronic expansion valve.

[0019] In some embodiments, the control unit brings 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 of the opening of the electronic expansion valve, including:

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

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

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

[0023]

[0024] Among them, U pre-sat is the pre-output opening of the electronic expansion valve, U(k) is the calculated opening value of the electronic expansion valve, and U max is the maximum opening of the electronic expansion valve, U min is the minimum opening of the electronic expansion valve; U i (k) is the integral output; U p (k) is 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] Matching the above device, the present invention provides a magnetic levitation motor on another aspect, including: the cooling device of the magnetic levitation motor described above.

[0026] Matching the above method, the present invention provides a storage medium on another aspect, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the above-mentioned cooling method for the magnetic levitation motor.

[0027] Matching the above method, the present invention provides a computer program product on another aspect, wherein the computer program product includes a computer program, and when the computer program product is processed and executed, the steps of the cooling method of the magnetic levitation motor are implemented.

[0028] The solution of the present invention is to set an electronic expansion valve on the coolant pipeline of the motor winding to control the flow of the coolant; determine whether to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and control the opening of the electronic expansion valve to the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0029] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0030] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a flow chart of an embodiment of a cooling method for a magnetic levitation motor of the present invention;

[0032] Figure 2 It is a structural schematic diagram of an embodiment of a cooling device for a magnetic levitation motor of the present invention;

[0033] Figure 3 It is a structural schematic diagram of the motor winding cooling pipeline;

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

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

[0036] Figure 6 It is a schematic diagram of the flow chart of the temperature control of the motor winding;

[0037] Figure 7Schematic diagram of the flow of the anti-saturation PI algorithm.

[0038] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0039] 102 - acquisition unit; 104 - control unit. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0041] According to an embodiment of the present invention, a cooling method for a magnetic levitation motor is provided, wherein a coolant pipeline is provided at the motor winding of the magnetic levitation motor; a coolant flows in the coolant pipeline, and the coolant can cool the motor winding; an electronic expansion valve is provided on the coolant pipeline; the electronic expansion valve is used to control the flow rate of the coolant. Figure 3 As shown, the coolant pipeline is wound around the motor winding, and the coolant enters the pipeline through the cooling inlet and cools the motor winding. After that, the coolant flows out from the return air pipeline and enters the intake air pipeline, completing a cycle. An electronic expansion valve is provided at the cooling inlet. By controlling the opening size of the electronic expansion valve, the coolant flow rate flowing into the coolant pipeline is controlled. When the coolant flow rate is large, the temperature of the motor winding is reduced, and when the coolant flow rate is small, the temperature of the motor winding is increased, thereby keeping the temperature of the motor winding within a certain range.

[0042] The wiring of the electronic expansion valve is as follows Figure 4 As shown in (a) and (b), the electronic expansion valve adopts the common anode wiring method. The out1 of the drive signal is connected to the A terminal of the electronic expansion valve, and the out2 of the drive signal is connected to the The out3 of the drive signal is connected to the B end of the electronic expansion valve, and the out4 of the drive signal is connected to the terminals, where the COM terminal is connected to the +24V power supply.

[0043] The control mode of the electronic expansion valve is four-wire eight-beat control mode, such as Figure 4 As shown in (c), during the control process, one or two phases are always energized, and the shaded part in the figure indicates that the phase is energized.

[0044] like Figure 1The flowchart of an embodiment of the method of the present invention is shown in FIG. The cooling method of 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 acquired.

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

[0047] In some embodiments, in 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; judging the relationship between the actual temperature difference and the 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.

[0048] The preset temperature difference is the difference between the reference temperature of the motor winding and the temperature of the motor winding when the opening of the electronic expansion valve was adjusted last time. When adjusting the opening of the electronic expansion valve, each adjustment is a cycle, and the reference temperature of the motor winding may be different in each cycle. The reference temperature can be regarded as the target temperature of the motor winding. The greater the temperature difference between the reference temperature and the current temperature, the more the temperature of the motor winding deviates from the target temperature. If the temperature difference gradually increases, it means that the current opening of the electronic expansion valve is not appropriate, causing the flow rate of the coolant to be too high or too low. At this time, 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 between the motor winding temperature and the reference temperature in the current cycle, it means that the temperature of the motor winding gradually deviates from the reference temperature, and the opening of the electronic expansion valve is too large or too small. At this time, the opening of the electronic expansion valve needs to be adjusted to make the temperature of the motor winding tend to the reference temperature; if fab2≥fab1, it means that the temperature of the motor winding gradually approaches the reference temperature, and the current opening of the electronic expansion valve is more appropriate. At this time, there is no need 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 winding can reach the appropriate range more quickly. After that, the opening of the electronic expansion valve will be within a certain range, so that the temperature of the motor winding can be stabilized within the appropriate range, thereby achieving the effect of quickly and accurately controlling the temperature of the motor winding.

[0050] At step S130, if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into a preset anti-saturation PI algorithm to obtain a calculated opening value of the electronic expansion valve.

[0051] In some embodiments, after determining to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding, it also includes a process of 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. The process specifically includes: after determining to adjust the opening of the electronic expansion valve, judging 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 at this time, then determining 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 at this time, then determining 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 determining not to adjust the opening of the electronic expansion valve.

[0052] In order to avoid the electronic expansion valve being in a saturated state after adjusting the opening, before adjustment, first determine whether it will enter a saturated state after PI adjustment according to the current opening and adjustment trend of the electronic expansion valve, and then determine whether to perform PI algorithm adjustment. Specifically, when the temperature Fdb of the motor winding is greater than the reference temperature Ref of the motor winding, it means that the temperature of the motor winding is high, and it is necessary to increase the opening of the electronic expansion valve to cool the motor winding. At this time, if the electronic expansion valve is already at the maximum opening, the opening calculation value obtained according to the PI algorithm will inevitably exceed the maximum opening, causing the electronic expansion valve to enter a saturated state. Therefore, in this case, the PI algorithm is not used to adjust the opening of the electronic expansion valve, and the electronic expansion valve is maintained at the current opening. When Fdb<Ref, it means that the temperature of the motor winding is low, and it is necessary to reduce the opening of the electronic expansion valve to heat up the motor winding. At this time, if the electronic expansion valve is already at the minimum opening, the opening calculation value obtained according to the PI algorithm will inevitably be less than the minimum opening. Therefore, in this case, the PI algorithm is not used to adjust the opening of the electronic expansion valve, and the electronic expansion valve is maintained at the current opening. When Fdb=Ref, it means that the temperature of the motor winding is in a suitable range, and there is no need to adjust the opening of the electronic expansion valve.

[0053] Figure 6 The flow chart of the temperature control of the motor winding is as follows: 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, 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, and determine whether fabs1-fabs2>0. If fabs1-fabs2>0, execute step 2; if fabs1-fabs2≤0, keep the opening of the electronic expansion valve unchanged.

[0055] Step 2, calculate the error err1 = -(Ref-Fdb), 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 Then keep the opening of the electronic expansion valve unchanged; otherwise, execute step 3.

[0056] Step 3: Determine whether 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 is kept unchanged, otherwise 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 electronic expansion valve opening according to the temperature of the motor winding and the reference temperature. The control block diagram is as follows: Figure 5 As shown, the input of the algorithm is the reference temperature Ref and the motor winding Fdb, and the output is the opening degree of the electronic expansion valve U pre-sat The specific formula of the PI algorithm is as follows:

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

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

[0060] In some embodiments, in step S130, the temperature of the motor winding and the reference temperature of the motor winding are brought into a preset anti-saturation PI algorithm to obtain a specific process of calculating the opening value of the electronic expansion valve, including: step S210 and step S220.

[0061] Step S210, bringing 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, the formula is:

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

[0063] Step S220, limiting the pre-output opening of the electronic expansion valve to obtain a calculated opening value of the electronic expansion valve, the formula is:

[0064]

[0065] In the formula, U pre-sat is the pre-output opening of the electronic expansion valve, U(k) is the calculated opening value of the electronic expansion valve, and U max is the maximum opening of the electronic expansion valve, U min is the minimum opening of the electronic expansion valve; U i (k) is the integral output, U i (k) = U i (k-1)+K i U p (k); K i is the integral control gain, the default U p (k) is the proportional output, U p (k) = K p err(k), err(k) = -(Ref-Fdb), the negative value is because when the temperature of the motor winding is lower than the reference temperature, the opening of the electronic expansion valve needs to be adjusted, and the relationship with Ref-Fdb is negatively correlated; 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 the anti-saturation PI algorithm, the opening of the electronic expansion valve will increase when the motor winding temperature is greater than the reference temperature, and will decrease when the motor winding temperature is less than the reference temperature. The greater the temperature difference, the greater the opening adjustment amount. By limiting the pre-output opening of the electronic expansion valve, the electronic expansion valve can be prevented from entering a saturated state during the adjustment process, making the opening adjustment more sensitive, and the motor winding temperature control more accurate, avoiding excessively high temperatures that affect the motor life, and condensation caused by too low temperatures that cause short circuits.

[0067] Figure 7 It is a flow chart of the anti-saturation PI algorithm, as shown in Figure 7 As shown, the method includes:

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

[0069] Step 12, calculate the proportional output, U p (k) = K p err(k), K p 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 The maximum opening of the electronic expansion valve, the default is 500; U min It is the minimum opening 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 according to the anti-saturation PI, it is possible to prevent the electronic expansion valve from being in an oversaturated or undersaturated state, making the adjustment of the opening more sensitive and the temperature control of the motor winding more precise.

[0077] According to the technical solution of this embodiment, an electronic expansion valve is set on the coolant pipeline of the motor winding to control the flow of the coolant; whether to adjust the opening of the electronic expansion valve is determined according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and the opening of the electronic expansion valve is controlled to be the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby 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 the cooling method for a magnetic levitation motor is also provided. A coolant pipeline is provided at the motor winding of the magnetic levitation motor; a coolant flows in the coolant pipeline, and the coolant can cool the motor winding; an electronic expansion valve is provided on the coolant pipeline; the electronic expansion valve is used to control the flow rate of the coolant. Figure 3 As shown, the coolant pipeline is wound around the motor winding, and the coolant enters the pipeline through the cooling inlet and cools the motor winding. After that, the coolant flows out from the return air pipeline and enters the intake air pipeline, completing a cycle. An electronic expansion valve is provided at the cooling inlet. By controlling the opening size of the electronic expansion valve, the coolant flow rate flowing into the coolant pipeline is controlled. When the coolant flow rate is large, the temperature of the motor winding is reduced, and when the coolant flow rate is small, the temperature of the motor winding is increased, thereby keeping the temperature of the motor winding within a certain range.

[0079] The wiring of the electronic expansion valve is as follows Figure 4 As shown in (a) and (b), the electronic expansion valve adopts the common anode wiring method. The out1 of the drive signal is connected to the A terminal of the electronic expansion valve, and the out2 of the drive signal is connected to the The out3 of the drive signal is connected to the B end of the electronic expansion valve, and the out4 of the drive signal is connected to the terminals, where the COM terminal is connected to the +24V power supply.

[0080] The control mode of the electronic expansion valve is four-wire eight-beat control mode, such as Figure 4 As shown in (c), during the control process, one or two phases are always energized, and the shaded part in the figure indicates that the phase is energized.

[0081] See also Figure 2 The schematic diagram of the structure of an embodiment of the device of the present invention is shown. The cooling device of 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 the reference temperature of the motor winding. The specific functions and processing of the acquisition unit 102 refer to step S110.

[0083] The control unit 104 is configured to determine whether to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding. The specific functions and processing of the control unit 104 refer to 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; judging the relationship between the actual temperature difference and the 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 of the motor winding and the temperature of the motor winding when the opening of the electronic expansion valve was adjusted last time. When adjusting the opening of the electronic expansion valve, each adjustment is a cycle, and the reference temperature of the motor winding may be different in each cycle. The reference temperature can be regarded as the target temperature of the motor winding. The greater the temperature difference between the reference temperature and the current temperature, the more the temperature of the motor winding deviates from the target temperature. If the temperature difference gradually increases, it means that the current opening of the electronic expansion valve is not appropriate, causing the flow rate of the coolant to be too high or too low. At this time, 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 between the motor winding temperature and the reference temperature in the current cycle, it means that the temperature of the motor winding gradually deviates from the reference temperature, and the opening of the electronic expansion valve is too large or too small. At this time, the opening of the electronic expansion valve needs to be adjusted to make the temperature of the motor winding tend to the reference temperature; if fab2≥fab1, it means that the temperature of the motor winding gradually approaches the reference temperature, and the current opening of the electronic expansion valve is more appropriate. At this time, there is no need 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 winding can reach the appropriate range more quickly. After that, the opening of the electronic expansion valve will be within a certain range, so that the temperature of the motor winding can be stabilized within the appropriate range, thereby achieving the effect of quickly and accurately controlling the temperature of the motor winding.

[0087] The control unit 104 is further configured to bring 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 of the opening of the electronic expansion valve if it is determined that the opening of the electronic expansion valve is to be adjusted. The specific functions and processing of the control unit 104 refer to step S130.

[0088] In some embodiments, the control unit 104, after determining to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding, 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, it includes: after determining to adjust the opening of the electronic expansion valve, judging 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 at this time, then determining 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 at this time, then determining 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 determining not to adjust the opening of the electronic expansion valve.

[0089] In order to avoid the electronic expansion valve being in a saturated state after adjusting the opening, before adjustment, first determine whether it will enter a saturated state after PI adjustment according to the current opening and adjustment trend of the electronic expansion valve, and then determine whether to perform PI algorithm adjustment. Specifically, when the temperature Fdb of the motor winding is greater than the reference temperature Ref of the motor winding, it means that the temperature of the motor winding is high, and it is necessary to increase the opening of the electronic expansion valve to cool the motor winding. At this time, if the electronic expansion valve is already at the maximum opening, the opening calculation value obtained according to the PI algorithm will inevitably exceed the maximum opening, causing the electronic expansion valve to enter a saturated state. Therefore, in this case, the PI algorithm is not used to adjust the opening of the electronic expansion valve, and the electronic expansion valve is maintained at the current opening. When Fdb<Ref, it means that the temperature of the motor winding is low, and it is necessary to reduce the opening of the electronic expansion valve to heat up the motor winding. At this time, if the electronic expansion valve is already at the minimum opening, the opening calculation value obtained according to the PI algorithm will inevitably be less than the minimum opening. Therefore, in this case, the PI algorithm is not used to adjust the opening of the electronic expansion valve, and the electronic expansion valve is maintained at the current opening. When Fdb=Ref, it means that the temperature of the motor winding is in a suitable range, and there is no need to adjust the opening of the electronic expansion valve.

[0090] Figure 6 The flow chart of the temperature control of the motor winding is as follows: 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, 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, and determine whether fabs1-fabs2>0. If fabs1-fabs2>0, execute step 2; if fabs1-fabs2≤0, keep the opening of the electronic expansion valve unchanged.

[0092] Step 2, calculate the error err1 = -(Ref-Fdb), 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 Then keep the opening of the electronic expansion valve unchanged; otherwise, execute step 3.

[0093] Step 3: Determine whether 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 is kept unchanged, otherwise 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 electronic expansion valve opening according to the temperature of the motor winding and the reference temperature. The control block diagram is as follows: Figure 5 As shown, the input of the algorithm is the reference temperature Ref and the motor winding Fdb, and the output is the opening degree of the electronic expansion valve U pre-sat The specific formula of the PI algorithm is as follows:

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

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

[0097] In some implementations, the control unit 104 brings 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 of the opening of the electronic expansion valve, including:

[0098] The control unit 104 is further configured to bring 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, and the formula is:

[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, and the formula is:

[0101]

[0102] In the formula, U pre-sat is the pre-output opening of the electronic expansion valve, U(k) is the calculated opening value of the electronic expansion valve, and U max is the maximum opening of the electronic expansion valve, U min is the minimum opening of the electronic expansion valve; U i (k) is the integral output, U i (k) = U i (k-1)+K i U p (k); K i is the integral control gain, the default U p (k) is the proportional output, U p (k) = K p err(k), err(k) = -(Ref-Fdb), the negative value is because when the temperature of the motor winding is lower than the reference temperature, the opening of the electronic expansion valve needs to be adjusted, and the relationship with Ref-Fdb is negatively correlated; 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 the anti-saturation PI algorithm, the opening of the electronic expansion valve will increase when the motor winding temperature is greater than the reference temperature, and will decrease when the motor winding temperature is less than the reference temperature. The greater the temperature difference, the greater the opening adjustment amount. By limiting the pre-output opening of the electronic expansion valve, the electronic expansion valve can be prevented from entering a saturated state during the adjustment process, making the opening adjustment more sensitive, and the motor winding temperature control more accurate, avoiding excessively high temperatures that affect the motor life, and condensation caused by too low temperatures that cause short circuits.

[0104] Figure 7 It is a flow chart of the anti-saturation PI algorithm, as shown in Figure 7 As shown, the method includes:

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

[0106] Step 12, calculate the proportional output, U p (k) = K p err(k), K p 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 The maximum opening of the electronic expansion valve, the default is 500; U min It is the minimum opening of the electronic expansion valve, the default value is 0.

[0112] The control unit 104 is further configured to control the opening of the electronic expansion valve to be the calculated opening value. The specific functions and processing of the control unit 104 refer to step S140.

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

[0114] Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0115] According to the technical solution of the present invention, an electronic expansion valve is arranged on the coolant pipeline of the motor winding to control the flow of the coolant; whether to adjust the opening of the electronic expansion valve is determined according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and the opening of the electronic expansion valve is controlled to be the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby 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 of the magnetic levitation motor is also provided. The magnetic levitation motor may include: the cooling device of the magnetic levitation motor described above.

[0117] Since the processing and functions implemented by the magnetic levitation motor of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0118] According to the technical solution of the present invention, an electronic expansion valve is arranged on the coolant pipeline of the motor winding to control the flow of the coolant; whether to adjust the opening of the electronic expansion valve is determined according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and the opening of the electronic expansion valve is controlled to be the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby 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 the cooling method of the magnetic levitation motor is also provided, wherein the storage medium includes a stored program, wherein when the program is run, the device where the storage medium is located is controlled to execute the cooling method of the magnetic levitation motor described above.

[0120] Since the processing and functions implemented by the storage medium of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0121] According to the technical solution of the present invention, an electronic expansion valve is arranged on the coolant pipeline of the motor winding to control the flow of the coolant; whether to adjust the opening of the electronic expansion valve is determined according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and the opening of the electronic expansion valve is controlled to be the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby 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 the cooling method of the magnetic levitation motor is also provided. The computer program product includes a computer program. When the computer program product is processed and executed, the steps of the cooling method of the magnetic levitation motor are implemented.

[0123] Since the processing and functions implemented by the computer program product of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0124] According to the technical solution of the present invention, an electronic expansion valve is arranged on the coolant pipeline of the motor winding to control the flow of the coolant; whether to adjust the opening of the electronic expansion valve is determined according to the temperature of the motor winding and the reference temperature of the motor winding; if it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into the anti-saturation PI algorithm to obtain the opening calculation value of the electronic expansion valve, and the opening of the electronic expansion valve is controlled to be the opening calculation value. By setting the electronic expansion valve to control the coolant flow, the opening of the electronic expansion valve is controlled according to the anti-saturation PI algorithm to prevent the electronic expansion valve from being in a saturated state, thereby improving the sensitivity of the opening adjustment and the accuracy of the motor winding temperature control.

[0125] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0126] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A cooling method for a magnetic levitation motor, characterized in that: A coolant pipeline is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipeline; The method comprises: Acquiring the temperature of the motor winding and the reference temperature of the motor winding; determining whether to adjust the opening of the electronic expansion valve according to the temperature of the motor winding and the reference temperature of the motor winding; If it is determined to adjust the opening of the electronic expansion valve, the temperature of the motor winding and the reference temperature of the motor winding are brought into a preset anti-saturation PI algorithm to obtain a calculated value of the opening of the electronic expansion valve; The opening degree of the electronic expansion valve is controlled to be the calculated opening degree value.

2. The cooling method of the magnetic levitation motor according to claim 1, characterized in that: Determining whether to adjust the opening of the electronic expansion valve according to 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; Determine the magnitude relationship between the actual temperature difference and the 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, it is determined not to adjust the opening of the electronic expansion valve.

3. The cooling method of the magnetic levitation motor according to claim 1 or 2, characterized in that: Also includes: After determining to adjust the opening of the electronic expansion valve, determining the magnitude 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 a preset maximum opening at this time, determining to adjust the opening of the electronic expansion valve; 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 a preset minimum opening at this time, determining 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, it is determined not to adjust the opening of the electronic expansion valve.

4. The cooling method of the magnetic levitation motor according to claim 1, characterized in that: Bringing 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 of the opening of the electronic expansion valve, including: The temperature of the motor winding and the reference temperature of the motor winding are brought into the preset anti-saturation PI algorithm to calculate the pre-output opening of the electronic expansion valve. The formula of the preset anti-saturation PI algorithm is: IN pre-sat =U p (k)+U i (k); The pre-output opening of the electronic expansion valve is limited to obtain a calculated opening value of the electronic expansion valve. The formula for limiting the pre-output opening of the electronic expansion valve is: Among them, U pre-sat is the pre-output opening of the electronic expansion valve, U(k) is the calculated opening value of the electronic expansion valve, and U max is the maximum opening of the electronic expansion valve, U min is the minimum opening of the electronic expansion valve; U i (k) is the integral output; U p (k) is 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.

5. A cooling device for a magnetic levitation motor, characterized in that: A coolant pipeline is provided at the motor winding of the magnetic levitation motor; an electronic expansion valve is provided on the coolant pipeline; The cooling device comprises: 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 according to the temperature of the motor winding and the reference temperature of the motor winding; The control unit is further configured to bring 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 of the opening of the electronic expansion valve if it is determined to adjust the opening of the electronic expansion valve; The control unit is further configured to control the opening degree of the electronic expansion valve to be 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 according to 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; Determine the magnitude relationship between the actual temperature difference and the 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, it is determined not to adjust the opening of the electronic expansion valve.

7. The cooling device for the magnetic levitation motor according to claim 5 or 6, characterized in that: The control unit further comprises: After determining to adjust the opening of the electronic expansion valve, determining the magnitude 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 a preset maximum opening at this time, determining to adjust the opening of the electronic expansion valve; 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 a preset minimum opening at this time, determining 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, it is determined not to adjust the opening of the electronic expansion valve.

8. A magnetic levitation motor, characterized in that: include: A cooling device for a magnetic levitation motor as claimed 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, the device where the storage medium is located is controlled to execute the cooling method for 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, the steps of the method according to any one of claims 1 to 4 are implemented.

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