Motor control method, device, motor and electrical equipment

Abstract

The present invention discloses a motor control method, device, motor, and electrical equipment. The method comprises: when an IGBT power switch in a motor drive circuit needs to switch carrier frequency, controlling the carrier frequency of the IGBT power switch to a target carrier frequency at one time; and then gradually controlling the control parameters of the motor drive circuit to switch to target control parameters corresponding to the target carrier frequency. The present invention can reduce the number of carrier frequency switches, thereby reducing the probability of motor loss of control. It also avoids inaccurate motor speed detection, which can ultimately cause motor operation chaos, overcurrent, loss of step, and other faults, leading to shutdown.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a motor control method, device, motor and electrical equipment. Background Art

[0002] In the field of motor control, the size of the carrier frequency affects the temperature rise of the IGBT power switch in the inverter circuit, the stability of the motor control, and the energy efficiency and noise of the motor. Therefore, in the motor control system, it is usually necessary to switch the carrier frequency according to the operating state of the motor. Generally, a low carrier frequency is used when the motor speed is low, and a high carrier frequency is used when the speed is high. During the carrier frequency switching process, the control parameters of the motor will change rapidly, and the operating state of the motor cannot keep up quickly. As a result, the current operating state of the motor cannot match the parameters after the carrier frequency is switched, and the speed detection is inaccurate, which ultimately causes the motor to operate chaotically, resulting in faults such as overcurrent and loss of step, which in turn causes the motor to shut down. To solve the above problems, the existing technology adopts a step-by-step carrier frequency switching method. However, the more times the carrier frequency is switched, the higher the probability of the motor losing control.

[0003] In the prior art, a method of switching the carrier frequency step by step is adopted, but the probability of the motor losing control increases with the number of times the carrier frequency is switched. Currently, no effective solution has been proposed. Summary of the Invention

[0004] The embodiments of the present invention provide a motor control method, device, motor and electrical equipment to solve the problem in the prior art of using a step-by-step carrier frequency switching method, but the more times the carrier frequency is switched, the higher the probability of the motor being out of control.

[0005] To solve the above technical problems, the present invention provides a motor control method, which includes:

[0006] When the IGBT power switch in the motor drive circuit needs to switch the carrier frequency, the carrier frequency of the IGBT power switch is controlled to switch to the target carrier frequency at one time;

[0007] Then, the control parameters of the motor drive circuit are gradually switched to the target control parameters corresponding to the target carrier frequency.

[0008] Furthermore, controlling the control parameters of the motor drive circuit to gradually switch to target control parameters corresponding to the target carrier frequency includes:

[0009] Determining target control parameters corresponding to the target carrier frequency;

[0010] determining an adjustment step size according to the target control parameter;

[0011] The control parameter is gradually adjusted to the target control parameter according to the adjustment step size.

[0012] Furthermore, when determining the adjustment step size according to the target control parameter, it is implemented according to the following formula:

[0013] ΔK=N1 / K 目标 ;

[0014] Wherein, ΔK is the adjustment step size, K 目标 is the target control parameter, and N1 is the first preset coefficient.

[0015] Furthermore, when determining the adjustment step size according to the target control parameter, it is implemented according to the following formula:

[0016] ΔK=N2 / (K 目标 -KPI1);

[0017] Wherein, ΔK is the adjustment step size, K 目标 is the target control parameter, KPI1 is the current control parameter, and N2 is the second preset coefficient.

[0018] Furthermore, after gradually adjusting the control parameter to the target control parameter according to the adjustment step, the method further includes:

[0019] Calculate the difference between the current control parameter and the target control parameter;

[0020] Correcting the adjustment step size according to the difference between the current control parameter and the target control parameter;

[0021] The smaller the difference is, the smaller the adjustment step is.

[0022] Furthermore, the control parameters include: a speed loop proportional coefficient, a speed loop integral coefficient, a current loop q-axis proportional coefficient, a current loop d-axis proportional coefficient, and a current loop integral coefficient.

[0023] The present invention also provides a motor control device, comprising:

[0024] A first control module is used to control the carrier frequency of the IGBT power switch in the motor drive circuit to switch to the target carrier frequency at one time when the carrier frequency needs to be switched;

[0025] The second control module is used to control the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency.

[0026] The present invention also provides a motor, comprising the above-mentioned motor control device.

[0027] The present invention also provides an electrical device comprising the above-mentioned motor.

[0028] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the program implements the above motor control method when executed by a processor.

[0029] By applying the technical solution of the present invention, when the IGBT power switch in the motor drive circuit needs to switch the carrier frequency, the carrier frequency of the IGBT power switch is controlled to switch to the target carrier frequency at one time, thereby reducing the number of carrier frequency switching times in a one-step manner and thereby reducing the probability of the motor being out of control; and then the control parameters of the motor drive circuit are controlled to switch gradually to the target control parameters corresponding to the target carrier frequency, thereby avoiding inaccurate speed detection of the motor, which ultimately causes chaotic operation of the motor, and causes faults such as overcurrent and loss of step, thereby leading to shutdown problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of a motor control method according to an embodiment of the present invention;

[0031] Figure 2 is a flow chart of a motor control method according to another embodiment of the present invention;

[0032] Figure 3 is a control block diagram of a motor according to an embodiment of the present invention;

[0033] Figure 4 FIG. 4 is a structural block diagram of a motor control device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings. It is apparent that the embodiments described are only some, not all, of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0035] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "a," "an," "the," and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, and unless the context clearly indicates otherwise, "a plurality" generally includes at least two.

[0036] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0037] It should be understood that although the terms "first," "second," etc. may be used to describe control modules in embodiments of the present invention, these control modules should not be limited to these terms. These terms are merely used to distinguish different control modules. For example, a first control module may also be referred to as a second control module, and similarly, a second control module may also be referred to as a first control module without departing from the scope of embodiments of the present invention.

[0038] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0039] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or device. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or device comprising the element.

[0040] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] Example 1

[0042] In the existing technology, during the process of switching the carrier frequency, the stability of the motor control is mainly determined by three parts: the speed loop, the current loop, and the position observer. The relevant control parameters are related to the carrier frequency. When the carrier frequency changes, the relevant control parameters will change rapidly, and the operating state of the motor cannot follow quickly, resulting in the current operating state of the motor being unable to match the parameters after switching the carrier frequency, inaccurate speed detection, and ultimately causing chaotic motor operation, resulting in overcurrent, loss of step and other faults and shutdowns.

[0043] To solve the above problem, the prior art adopts a method of switching the carrier frequency step by step. However, the more times the carrier frequency is switched, the higher the probability of the motor being out of control.

[0044] In order to solve the above problems, this embodiment provides a motor control method. Figure 1 is a flow chart of a motor control method according to an embodiment of the present invention. Figure 1 As shown, the method includes:

[0045] S101 , when an IGBT power switch in a motor drive circuit needs to switch a carrier frequency, controlling the carrier frequency of the IGBT power switch to be switched to a target carrier frequency at one time.

[0046] By using the one-step approach described above, the number of carrier frequency switching times is reduced, thereby reducing the probability of the motor losing control.

[0047] S102 , then controlling the control parameters of the motor drive circuit to gradually switch to target control parameters corresponding to the target carrier frequency.

[0048] After the carrier frequency of the IGBT power switch is switched to the target carrier frequency at one time, if it is not controlled by a corresponding program, the control parameters will change rapidly, causing chaotic motor operation and faults such as overcurrent and loss of step. Therefore, it is necessary to control the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency after the carrier frequency of the IGBT power switch is switched to the target carrier frequency at one time.

[0049] The motor control method of this embodiment controls the carrier frequency of the IGBT power switch to be switched to the target carrier frequency at one time when the IGBT power switch in the motor drive circuit needs to switch the carrier frequency. This reduces the number of carrier frequency switching times in a one-step manner, thereby reducing the probability of the motor losing control. The control parameters of the motor drive circuit are then controlled to gradually switch to the target control parameters corresponding to the target carrier frequency, thereby avoiding inaccurate speed detection of the motor, which ultimately causes chaotic operation of the motor, overcurrent, loss of step and other faults, and thus leads to shutdown problems.

[0050] In actual applications, before and after the carrier frequency of the IGBT power switch is switched, the carrier frequency variation may be small. In this case, switching can be performed in a smaller number of switching times. The carrier frequency variation may also be large. In order to avoid the control parameters changing too quickly, many switching times are required to achieve the target control parameters. Therefore, controlling the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency includes: determining the target control parameters corresponding to the target carrier frequency; determining the adjustment step according to the target control parameters; and gradually adjusting the control parameters to the target control parameters according to the adjustment step.

[0051] Specifically, when determining the adjustment step size according to the target control parameter, it is implemented according to the following formula: ΔK=N1 / K 目标 ; Wherein, ΔK is the adjustment step, K 目标 is the target control parameter, N1 is a first preset coefficient, and a suitable value can be determined in advance through experiments.

[0052] When determining the adjustment step size according to the target control parameter, it can also be achieved according to the following formula: ΔK=N2 / (K 目标-KPI1); wherein ΔK is the adjustment step, K 目标 is the target control parameter, KPI1 is the current control parameter, and N2 is a second preset coefficient, which can be determined by experiments in advance.

[0053] During the adjustment process, the control parameter will gradually approach the target control parameter. If the same adjustment step size is maintained, the target control parameter may be exceeded, resulting in over-adjustment. To avoid this, after gradually adjusting the control parameter to the target control parameter according to the adjustment step size, the method further includes: calculating the difference between the current control parameter and the target control parameter; and correcting the adjustment step size based on the difference between the current control parameter and the target control parameter. The smaller the difference, the smaller the adjustment step size. That is, the closer the control parameter is to the target control parameter, the smaller the adjustment step size will be.

[0054] In this embodiment, the control parameters include a speed loop proportional coefficient, a speed loop integral coefficient, a current loop q-axis proportional coefficient, a current loop d-axis proportional coefficient, and a current loop integral coefficient.

[0055] Figure 2 FIG. 1 is a flow chart of a motor control method according to another embodiment of the present invention. In this embodiment, a compressor is taken as an example to explain the present invention in detail. Figure 2 As shown, the method includes the following preferred steps:

[0056] S1, determine whether the IGBT power switch needs to switch the carrier frequency, if yes, execute step S2, if not, execute step S6.

[0057] S2, confirm the target parameter K corresponding to the target carrier frequency F 目标 .

[0058] S3, according to the target parameter K 目标 Determine the adjustment step size;

[0059] S4, controlling the control parameters of the motor drive circuit to be gradually increased / decreased according to the above adjustment step size.

[0060] For example, assuming the adjustment step size is 10 / K 目标 , the current control parameter is KPI1, then the control parameter after the first adjustment is KPI2=KPI1±10 / K 目标 ; The control parameter after the second adjustment KPI3=KPI2±10 / K 目标 ; The control parameter after the third adjustment is KPI4 = KPI3 ± 10 / K 目标 ; ...the control parameter after the n-1th adjustment KPIn=KPI(n-1)±10 / K 目标 , and so on.

[0061] S5, determine whether the current control parameter reaches the target parameter K 目标 ; If yes, execute step S6, if no, return to step S4.

[0062] S6, keep the current control parameters unchanged.

[0063] In the motor control method of this embodiment, when the carrier frequency needs to be switched, SVPWM immediately performs carrier frequency switching, controlling the carrier frequency of the IGBT power switch to switch to the target carrier frequency in one step, without having to switch the carrier frequency in segments multiple times. While switching the carrier frequency, current and speed will fluctuate, and each time the carrier frequency is switched, corresponding control code needs to be written according to the corresponding carrier frequency. Too much code will occupy too many resources, which is inefficient, and reduces the risk of motor loss of control caused by carrier frequency switching. Therefore, the target control parameter K is determined. 目标 After that, the initial control parameters are adaptively and gradually accumulated to make the control parameters reach the target control parameters K 目标 In this way, the effect of switching the carrier frequency and switching the control parameters can be achieved smoothly and linearly, and the number of carrier frequency switching can be reduced, and the amount of code in the control program can be reduced.

[0064] Figure 3 is a control block diagram of a motor according to an embodiment of the present invention, as shown in FIG. Figure 3 As shown in the figure, it is necessary to adjust the control parameters of the current loop, speed loop and position observer to improve the stability of the entire control system. The above control parameters include the following parameters: speed loop proportional coefficient KPSC, KPSC = 2*Zeta*Jm*Wn / Kt; where Zeta is the speed loop damping coefficient, which can reduce the overshoot caused by system zeroing, Jm is the motor's moment of inertia, which is a parameter of the motor itself, Wn is the speed loop bandwidth, which affects the stability of the speed loop system; Kt is the torque constant, which is a parameter of the motor itself; speed loop integral coefficient KISC, KISC = Jm*Wn^2 / Kt; current loop q-axis proportional coefficient KPCC_q, KPCC_q = Lq*Wc, where Lq is the motor's q-axis inductance, which is a parameter of the motor itself; Wc is the current loop bandwidth, which affects the stability of the current loop regulation and needs to be debugged according to the carrier frequency; current loop d-axis proportional coefficient KPCC_d, KPCC_d = Ld*Wc, where Ld is the motor's d-axis inductance, which is a parameter of the motor itself; current loop integral coefficient KICC = Rs*Wc, where Rs is the resistance of the motor winding.

[0065] The above parameters need to be debugged according to the target carrier frequency of the switch to determine the target control parameters that are most suitable for the carrier frequency and the motor.

[0066] After the control parameter reaches the target control parameter, keep the parameter stable and unchanged as the current carrier frequency control parameter, and wait for the next carrier frequency switching to make adjustments. In the above formula, KPIn is the parameter after gradual accumulation. When it is equal to the target parameter, stop accumulation / subtraction and keep the parameter unchanged. F is the target carrier frequency, 10 / K 目标 To adjust the step length, it can be adjusted according to the specific control system.

[0067] For example, in an air-conditioning control system, the control carrier frequency of the compressor motor is usually switched from 5000 Hz to 8000 Hz. When the carrier frequency is switched, the control parameter is added / subtracted from the original value at a rate of 10 / 8000 each time until it reaches the target control parameter.

[0068] The control method of this embodiment can effectively avoid drastic jumps in control parameters caused by direct switching of the carrier frequency, which may cause the existing operating state of the motor to be unable to match the parameters after switching the carrier frequency, resulting in the motor losing control and shutting down due to a fault, thereby effectively improving the stability of the motor operation.

[0069] Example 2

[0070] This embodiment provides a motor control device, Figure 4 FIG. 1 is a structural block diagram of a motor control device according to an embodiment of the present invention. Figure 4 As shown, the device includes:

[0071] The first control module 10 is configured to control the carrier frequency of the IGBT power switch in the motor drive circuit to switch to the target carrier frequency at one time when the carrier frequency of the IGBT power switch needs to be switched.

[0072] By using the one-step approach described above, the number of carrier frequency switching times is reduced, thereby reducing the probability of the motor losing control.

[0073] The second control module 20 is configured to control the control parameters of the motor drive circuit to gradually switch to target control parameters corresponding to the target carrier frequency.

[0074] After the carrier frequency of the IGBT power switch is switched to the target carrier frequency at one time, if it is not controlled by a corresponding program, the control parameters will change rapidly, causing chaotic motor operation and faults such as overcurrent and loss of step. Therefore, it is necessary to control the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency after the carrier frequency of the IGBT power switch is switched to the target carrier frequency at one time.

[0075] The motor control device of this embodiment controls the carrier frequency of the IGBT power switch in the motor drive circuit to switch to the target carrier frequency at one time through the first control module 10 when the carrier frequency needs to be switched. This reduces the number of carrier frequency switching times in a one-step manner, thereby reducing the probability of the motor being out of control. Then, the control parameters of the motor drive circuit are controlled by the second control module 20 to gradually switch to the target control parameters corresponding to the target carrier frequency, thereby avoiding inaccurate detection of the motor speed, which ultimately causes chaotic operation of the motor, and causes faults such as overcurrent and loss of step, which in turn leads to shutdown problems.

[0076] In actual applications, before and after the carrier frequency switching of the IGBT power switch, the carrier frequency change amplitude may be small. At this time, switching can be performed in a smaller number of switching times. The carrier frequency change amplitude may also be large. In order to avoid the control parameters changing too quickly, many switching times are required to achieve the target control parameters. Therefore, the second control module 20 is specifically used to: determine the target control parameters corresponding to the target carrier frequency; determine the adjustment step size according to the target control parameters; and gradually adjust the control parameters to the target control parameters according to the adjustment step size.

[0077] Specifically, when the second control module 20 determines the adjustment step size according to the target control parameter, it is implemented according to the following formula: ΔK=N1 / K 目标 ; Wherein, ΔK is the adjustment step, K 目标 is the target control parameter, N1 is a first preset coefficient, and a suitable value can be determined in advance through experiments.

[0078] When determining the adjustment step size according to the target control parameter, it can also be achieved according to the following formula: ΔK=N2 / (K 目标 -KPI1); wherein ΔK is the adjustment step, K 目标 is the target control parameter, KPI1 is the current control parameter, and N2 is a second preset coefficient, which can be determined by experiments in advance.

[0079] During the adjustment process, the control parameter will gradually approach the target control parameter. If the same adjustment step is maintained, the target control parameter may be exceeded, resulting in over-adjustment. To avoid this, the second control module 20 is further configured to: after gradually adjusting the control parameter to the target control parameter according to the adjustment step, calculate the difference between the current control parameter and the target control parameter; and modify the adjustment step according to the difference between the current control parameter and the target control parameter. The smaller the difference, the smaller the adjustment step. That is, the closer the control parameter is to the target control parameter, the smaller the adjustment step will be.

[0080] In this embodiment, the control parameters include a speed loop proportional coefficient, a speed loop integral coefficient, a current loop q-axis proportional coefficient, a current loop d-axis proportional coefficient, and a current loop integral coefficient.

[0081] Example 3

[0082] This embodiment provides a motor, including the motor control device of the above embodiment, which is used to reduce the number of carrier frequency switching, thereby reducing the probability of the motor losing control, while avoiding inaccurate motor speed detection, which ultimately causes chaotic motor operation, overcurrent, loss of step and other faults that lead to shutdown, thereby improving the operating stability of the motor.

[0083] Example 4

[0084] This embodiment provides an electrical device, including the motor of the above embodiment, which is used to reduce the number of carrier frequency switching, thereby reducing the probability of the motor losing control, and at the same time avoiding inaccurate motor speed detection, which ultimately causes the motor to operate in a disorderly manner, and cause faults such as overcurrent and loss of step, which in turn lead to shutdown problems, thereby improving the operating stability of the motor and thus improving the operating stability of the entire electrical device.

[0085] Example 5

[0086] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the above-mentioned motor control method is implemented.

[0087] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, i.e., they may be located in one place or distributed across multiple network elements. Some or all of these modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0088] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A motor control method, characterized in that: The method comprises: When the IGBT power switch in the motor drive circuit needs to switch the carrier frequency, the carrier frequency of the IGBT power switch is controlled to switch to the target carrier frequency at one time; Then, controlling the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency; the method includes: determining the target control parameters corresponding to the target carrier frequency; determining an adjustment step size according to the target control parameters; and gradually adjusting the control parameters to the target control parameters according to the adjustment step size; Stepwise adjusting the control parameter to the target control parameter according to the adjustment step size includes: Calculate the difference between the current control parameter and the target control parameter; The adjustment step is modified according to the difference between the current control parameter and the target control parameter; wherein, the smaller the difference is, the smaller the adjustment step is.

2. The method according to claim 1, characterized in that When determining the adjustment step size according to the target control parameter, it is implemented according to the following formula: ΔK=N1 / K 目标 ; Wherein, ΔK is the adjustment step size, K 目标 is the target control parameter, and N1 is the first preset coefficient.

3. The method according to claim 1, characterized in that When determining the adjustment step size according to the target control parameter, it is implemented according to the following formula: ΔK=N2 / (K 目标 -KPI1); Wherein, ΔK is the adjustment step size, K 目标 is the target control parameter, KPI1 is the current control parameter, and N2 is the second preset coefficient.

4. The method according to claim 1, wherein The control parameters include: a speed loop proportional coefficient, a speed loop integral coefficient, a current loop q-axis proportional coefficient, a current loop d-axis proportional coefficient, and a current loop integral coefficient.

5. A motor control device, characterized in that: The device comprises: A first control module is used to control the carrier frequency of the IGBT power switch in the motor drive circuit to switch to the target carrier frequency at one time when the carrier frequency needs to be switched; a second control module, configured to control the control parameters of the motor drive circuit to gradually switch to the target control parameters corresponding to the target carrier frequency; the control module comprising: determining the target control parameters corresponding to the target carrier frequency; determining an adjustment step size according to the target control parameters; and gradually adjusting the control parameters to the target control parameters according to the adjustment step size; Stepwise adjusting the control parameter to the target control parameter according to the adjustment step size includes: Calculate the difference between the current control parameter and the target control parameter; The adjustment step is modified according to the difference between the current control parameter and the target control parameter; wherein, the smaller the difference is, the smaller the adjustment step is.

6. A motor, characterized in that: Including the motor control device according to claim 5.

7. An electrical device, characterized in that: Including the motor according to claim 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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