Motor rotating speed control method, motor controller and three-phase motor

Abstract

The embodiment of the invention discloses a motor rotating speed control method, a motor controller and a three-phase motor, and the motor rotating speed control method comprises the steps: controlling the motor to carry out short-circuit braking for a preset time length, and enabling the preset time length to be smaller than or equal to 150ms; the D-axis current and the Q-axis current input into the motor are controlled to be 0, and the real-time rotating speed omega and the real-time position theta of the motor are obtained; according to the real-time position theta, the real-time rotating speed omega and the preset rotating speed n1, closed-loop control is conducted on the motor, so that the motor operates at the preset rotating speed n1, and the value range of n1 is 0 rpm to 10 rpm. According to the invention, the technical problem of poor safety of the motor in the prior art when the motor is used in a high-speed clockwise and countercurrent environment is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a motor speed control method, a motor controller and a three-phase motor. Background Art

[0002] When the motor is in a downstream or upstream environment, the motor will rotate when it stops due to the drive of airflow and water flow. When the flow rate of the fluid is fast, the motor will also rotate at a higher speed. At this time, starting the motor will easily cause the bus voltage to increase, thereby damaging the controller. Moreover, when the motor rotates at high speed driven by the fluid, it will also be in a more dangerous state. For example, when the fan stops in a downstream or upstream state, the wind will drive the impeller to rotate, thereby driving the motor to rotate. The greater the external wind speed, the faster the motor will rotate, causing the fan to be in a dangerous state of high-speed operation. At this time, starting the motor may also cause the motor bus voltage to increase, thereby damaging the components in the controller.

[0003] It can be seen that the motor in the related art has a technical problem of poor safety when used in a high-speed forward and reverse flow environment. In view of the above problems, no effective solution has been proposed yet.

[0004] The above information disclosed in the background technology section is only used to enhance the understanding of the background technology of the technology described in this article. Therefore, the background technology may contain some information that does not form the known prior art for those skilled in the art. Summary of the invention

[0005] The embodiments of the present invention provide a motor speed control method, a motor controller and a three-phase motor, so as to at least solve the technical problem in the related art that the motor has poor safety when used in a high-speed forward and reverse current environment.

[0006] According to a first aspect of an embodiment of the present invention, a motor speed control method is provided, including: controlling the motor to perform short-circuit braking for a preset duration, the preset duration being less than or equal to 150ms; controlling the D-axis current and the Q-axis current of the input motor to be 0, and obtaining the real-time speed ω and the real-time position θ of the motor; performing closed-loop control of the motor according to the real-time position θ, the real-time speed ω and the preset speed n1, so that the motor runs at the preset speed n1, wherein the value range of n1 is 0rpm to 10rpm.

[0007] Further, according to the real-time position θ, the real-time speed ω and the preset speed n1, the motor is closed-loop controlled, including: at least according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit ; According to the limiting current I limit, the input current I is limited to the bus voltage U greater than the preset voltage threshold U t When the bus voltage U is reduced, the input current I is used to control the action of the motor. The input current I=(I d 2 +I q 2 ) 1 / 2 , I d is the D-axis current of the input motor, I q is the Q-axis current of the input motor.

[0008] Furthermore, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , including: when the bus voltage U is greater than the preset voltage threshold U t In the case of limit Reduce.

[0009] Furthermore, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , including: determining the limiting current I limit =k1*ΔU+∫(k2*ΔU)+I0, where k1 is the preset value, K2 is positively correlated with the real-time speed ω, ΔU=U t -U, I0 is the initial value of the input current I.

[0010] Furthermore, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , also includes: in determining the limiting current I limit Greater than the current threshold I max In the case of limit Reduce, so that the limiting current I limit Less than or equal to the current threshold I max , where the current threshold I max is the default value.

[0011] Furthermore, according to the limiting current I limit , limiting the magnitude of the input current I, including: determining the direction of rotation of the motor; when the motor rotates in the forward direction, controlling the input current I ≥ the limiting current I limit ; When the motor rotates in the reverse direction, control the input current I≤limit current I limit .

[0012] Further, according to the limiting current I limitBefore limiting the size of the input current I, the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1, and also includes: calculating the target torque according to the real-time position θ, the real-time speed ω and the preset speed n1, and the target torque is used to drive the motor to adjust from the real-time speed ω to the preset speed n1; determining the corresponding given current and given flux according to the target torque; determining the D-axis current and Q-axis current of the input motor according to the given current and the given flux.

[0013] Furthermore, the real-time rotational speeds of the D-axis current and the Q-axis current of the input motor are determined according to the given current and the given flux, including: obtaining the real-time current of the motor, and performing closed-loop control on the real-time current according to the given current, wherein the real-time current is the real-time three-phase current of the motor; obtaining the real-time flux of the motor, and performing closed-loop control on the real-time flux according to the given flux; determining the D-axis current and the Q-axis current based on the closed-loop control of the real-time current and the closed-loop control of the real-time flux.

[0014] Furthermore, obtaining the real-time flux of the motor includes: obtaining the three-phase current and three-phase voltage of the motor in real time; and calculating the real-time flux of the motor through a flux observer model according to the three-phase current and three-phase voltage.

[0015] Furthermore, obtaining the real-time speed ω and real-time position θ of the motor includes: obtaining the three-phase current and three-phase voltage of the motor; and calculating the real-time speed ω and real-time position θ through a flux observer based on the three-phase current and three-phase voltage.

[0016] Furthermore, after the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1 so that the motor runs at the preset speed n1, the method also includes: obtaining the target speed n2; and controlling the motor so that the motor runs at the target speed n2.

[0017] According to a second aspect of an embodiment of the present invention, a computer program product is also provided, comprising computer instructions, and the computer instructions implement the above method when executed by a processor.

[0018] According to a third aspect of an embodiment of the present invention, a non-volatile storage medium is further provided. The non-volatile storage medium includes a stored program. When the program is running, the device where the non-volatile storage medium is located is controlled to execute the above method.

[0019] According to a fourth aspect of an embodiment of the present invention, there is further provided a motor controller, comprising a processor, wherein the processor is used to run a program, and the above method is executed when the program is run.

[0020] According to a fifth aspect of an embodiment of the present invention, a three-phase motor is also provided. The three-phase motor includes a motor body and a motor controller electrically connected thereto, and the motor controller controls the operation of the motor body, wherein the motor controller is the above-mentioned motor controller.

[0021] The motor speed control method of the embodiment of the present invention can effectively decelerate the motor by first controlling the motor to perform short-circuit braking of a preset duration. Since the short-circuit braking duration is controlled to be less than or equal to 150ms in the embodiment of the present application, the short-circuit braking will effectively control the increase of the bus voltage so that it will not exceed the threshold value, and the normal operation of the internal components of the motor can be ensured. Then, the motor is given a zero current to obtain its real-time speed, and then the speed is closed-loop controlled, and finally it is operated at a preset speed n1 of 0rpm to 10rpm. The motor speed control method of the embodiment of the present invention can effectively control the motor to be stationary or at a low speed under the condition of forward and reverse flow, thereby improving its safety, and is conducive to avoiding bus overvoltage during the motor startup process, thereby ensuring the normal startup of the motor, and solving the problem of poor safety of the motor in the related art when used in a high-speed forward and reverse flow environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 A schematic diagram of a flow chart of a motor speed control method provided by an embodiment of the present invention;

[0024] Figure 2 The figure is a schematic diagram of the control process of a fan in a headwind or headwind state using the motor speed control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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 creative work should fall within the scope of protection of the present invention.

[0026] It should be noted that the terms "first", "second" and the like in the specification, claims and drawings of the present invention are used to distinguish different objects rather than to limit a specific order.

[0027] As described in the background technology section, when the motor is stopped and placed in a downstream or upstream environment, the fan blades may be driven by airflow, water flow and other fluids to rotate. When the fluid flow rate is high, the motor may face the danger of high-speed operation. At this time, starting the motor is likely to cause the bus voltage to rise, which in turn exceeds the safety value and causes damage to components. Therefore, the motor in a high-speed downstream or upstream environment has the problem of difficulty in starting and poor safety. In order to solve this technical problem, an embodiment of the present invention provides a motor speed control method. Figure 1 is a flow chart of a motor speed control method according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0028] Step S102, controlling the motor to perform short-circuit braking for a preset time, wherein the preset time is less than or equal to 150 ms;

[0029] Step S104, controlling the D-axis current and the Q-axis current input to the motor to be 0, and obtaining the real-time rotation speed ω and the real-time position θ of the motor;

[0030] Step S106 , performing closed-loop control on the motor according to the real-time position θ, the real-time rotational speed ω and the preset rotational speed n1 , so that the motor runs at the preset rotational speed n1 , wherein the value range of n1 is 0 rpm to 10 rpm.

[0031] The embodiment of the present application adopts the motor speed control method of the above scheme. First, by controlling the motor to perform short-circuit braking of a preset duration, the motor can be effectively decelerated. Since the short-circuit braking duration is controlled to be less than or equal to 150ms in the embodiment of the present application, the short-circuit braking will effectively control the increase of the bus voltage so that it will not exceed the threshold value, and the normal operation of the internal components of the motor can be guaranteed. Then, the motor is given a zero current to obtain its real-time speed, and then the speed is closed-loop controlled, and finally it is operated at a preset speed n1 of 0rpm to 10rpm. The motor speed control method of the embodiment of the present invention can effectively control the motor to be stationary or low-speed in the case of forward and reverse flow, improve its safety, and is conducive to avoiding bus overvoltage during motor startup, thereby ensuring the normal startup of the motor, and solving the problem of poor safety of motors in high-speed forward and reverse flow environments in related technologies.

[0032] Among them, the above-mentioned operation of making the motor run at a preset speed n1 means that the motor is in a state of the preset speed n1. When n1 is 0rpm, the motor is in a stationary state. When n1 is not 0, the motor rotates at the preset speed n1.

[0033] The D-axis current and Q-axis current are two key parameters in the motor control process, which represent the current components on the motor direct axis (D-axis) and quadrature axis (Q-axis) respectively. The currents of these two axes can be controlled independently, and the motor performance can be precisely adjusted by decoupling. Specifically, the D-axis current (I d ) is consistent with the magnetic flux direction of the motor and is mainly used to control the magnetic field strength and flux linkage of the motor. q ) is perpendicular to the rotor magnetic field of the motor and is mainly used to control the torque output of the motor. The motor short-circuit brake uses the three-phase short circuit inside the motor to achieve the purpose of braking the motor. In actual operation, switching devices such as IGBT and MOSFET are usually used to control the brake of the motor. By disconnecting the power supply of the motor and short-circuiting the three-phase line inside the motor, the motor is stalled in a short time to achieve the purpose of rapid braking.

[0034] Specifically, the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1, including: at least according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit ; According to the limiting current I limit , the input current I is limited to the bus voltage U greater than the preset voltage threshold U t When the bus voltage U is reduced, the input current I is used to control the action of the motor. The input current I=(I d 2 +I q 2 ) 1 / 2 , I d is the D-axis current of the input motor, I q The input current I is the input current used to control the motor, which is the input current in a two-dimensional rotating coordinate system, including the D-axis current and the Q-axis current.

[0035] In this embodiment, during the closed-loop control of the motor speed, the motor input current I is limited. Specifically, the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , and then use I limit The input current I is limited to the bus voltage U greater than the preset voltage threshold U t In the case of limit The input current I is limited, thereby reducing the bus voltage U, avoiding damage to components due to excessive bus voltage U during the motor closed-loop control process, and ensuring the safety and reliability of the motor speed control process.

[0036] In order to ensure that the bus voltage U is not over-voltage, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , including: when the bus voltage U is greater than the preset voltage threshold U t In the case of limit Reduce.

[0037] In this embodiment, when the bus voltage U is greater than the preset voltage threshold U t When the current I limit Reduce, so that according to the bus voltage U and the preset voltage threshold U t The size of the current I is adjusted to limit the input current, thereby better controlling the bus voltage U to prevent it from being too high and causing damage to components.

[0038] As mentioned above, the limiting current I limit is at least based on the bus voltage U and the preset voltage threshold U t , which is used to limit the input current I, so as to ensure that the bus voltage U is not over-voltage. In actual implementation, the limiting current I limit There may be different specific ways, and different I limit The limiting current I determined by the determination method limit The control effect on the bus voltage rise is different. Of course, the limiting current I limit The parameters used in the process are not limited to the bus voltage U and the preset voltage threshold U t In this embodiment, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , including: determining the limiting current I limit =k1*ΔU+∫(k2*ΔU)+I0, where k1 is the preset value, K2 is positively correlated with the real-time speed ω, ΔU=U t -U, I0 is the initial value of the input current I.

[0039] As a preferred embodiment, I of this embodiment limit =k1*ΔU+∫(k2*ΔU)+I0, where k1 is a preset value, K2 is positively correlated with the real-time speed ω, ΔU=U t -U, I0 is the initial value of the input current I. That is, in the above formula, k1 is a preset fixed value, and by designing and adjusting it, its response speed to the bus voltage U exceeding the threshold can be controlled, that is, the larger the value of k1, the faster I limitThe faster the speed of reduction, the more timely the bus voltage U can be controlled, reducing the damage to components caused by long-term bus overvoltage. The value of k2 is set to be positively correlated with the real-time speed ω of the motor. Since the real-time speed ω of the motor is affected by the flow rate of the current working fluid, the faster the fluid flow rate, the faster the real-time speed ω of the motor. That is, the value of k2 is essentially positively correlated with the flow rate of the working fluid in the motor. The smaller the fluid flow rate, the smaller k2. The increase in the fluid flow rate increases the value of k2. Therefore, the limiting current I limit The value of can be dynamically adjusted with the flow rate of the fluid, thereby dynamically limiting the input current I in the forward and reverse flow states, and ultimately achieving a better control effect on the rise of the bus voltage U. In this embodiment, the limiting current I is determined limit The basis is not only the bus voltage U and the preset voltage threshold U t , and also includes the real-time speed ω of the motor. Since the real-time speed ω reflects the real-time flow rate of the ambient fluid, using the real-time speed ω to determine k2 can better reflect I limit Dynamically adjust the current limit I limit The value of is dynamically adjusted with the flow rate of the fluid. In this embodiment, when the motor is started to be controlled, its speed can be effectively reduced by short-term braking. Because the braking time is controlled to be short, when the bus voltage U exceeds the preset voltage threshold U t The braking is ended before the bus voltage U exceeds the threshold. Then the motor speed is closed-loop controlled and I limit The function limits the input current I of the motor to ensure that the motor will not cause bus overvoltage in any environment with a large fluid flow rate. In a preferred embodiment, K2 is proportional to the real-time rotation speed ω of the motor.

[0040] For example, in one specific embodiment, I limit is the above-mentioned limiting current, which is used to limit the upper limit of the input current I. Assuming that the given current (input current I) determined in the closed-loop control process of the motor is 5A, the motor controller will increase the input current I to 5A through closed-loop control. However, if the bus voltage U exceeds the preset voltage threshold U t , then the I calculated by the formula limit will decrease, for example, the calculated I limit =3A, then I limit The input current I will be limited to 3A, and the real-time input current will be controlled to 3A through closed loop instead of 5A, thus avoiding the situation where the bus overvoltage damages the controller.

[0041] In this embodiment, according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit, also includes: in determining the limiting current I limit Greater than the current threshold I max In the case of limit Reduce, so that the limiting current I limit Less than or equal to the current threshold I max , where the current threshold I max is the preset value. That is, when using I limit =k1*ΔU+∫(k2*ΔU)+I0Calculate the limiting current I limit On the basis of the preset current threshold I max The calculated limiting current I limit Further limiting is performed, and finally the limiting current I limit Does not exceed the current threshold I max , thereby further improving system security.

[0042] As described above, when the motor is in its working fluid environment, the flow of the fluid will drive the impeller and then drive the motor to rotate. Specifically, the direction of the motor rotation may be forward or reverse. The forward direction mentioned here means that the direction in which the motor rotates driven by the fluid is the same as the direction in which the motor rotates when it is working normally. At this time, the motor is in a downstream state. The reverse direction means that the direction in which the motor rotates driven by the fluid is opposite to the direction in which the motor rotates when it is working normally. At this time, the motor is in a countercurrent state. Regardless of whether the motor rotates forward or reversely, the input current I needs to control the motor to a state in which it rotates forward and the rotation speed is a preset speed n1. In order to effectively limit the input current I in both the forward and reverse wind states, in this embodiment, according to the limiting current I limit , limiting the magnitude of the input current I, including: determining the direction of rotation of the motor; when the motor rotates in the forward direction, controlling the input current I ≥ the limiting current I limit ; When the motor rotates in the reverse direction, control the input current I≤limit current I limit .

[0043] According to the limiting current I limit, before limiting the magnitude of the input current I, the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1, and also includes: calculating the target torque according to the real-time position θ, the real-time speed ω and the preset speed n1, the target torque is used to drive the motor to adjust from the real-time speed ω to the preset speed n1; according to the target torque, determining the corresponding given current and given flux; according to the given current and given flux, determining the D-axis current and Q-axis current of the input motor. In this embodiment, during the control process, the real-time speed ω of the motor is first obtained, and then the required torque is calculated according to the difference between the speed and the expected preset speed n1. According to the calculated torque requirement, the controller calculates the current that should be applied to the motor to achieve this torque, and then obtains the flux value that should exist in order to achieve the required torque by querying the relationship table between the flux and the current established in advance.

[0044] Specifically, according to the given current and the given flux, the real-time speed of the D-axis current and the Q-axis current of the input motor is determined, including: obtaining the real-time current of the motor, and performing closed-loop control on the real-time current according to the given current, the real-time current being the real-time three-phase current of the motor; obtaining the real-time flux of the motor, and performing closed-loop control on the real-time flux according to the given flux; based on the closed-loop control of the real-time current and the closed-loop control of the real-time flux, the D-axis current and the Q-axis current are determined. In this embodiment, the motor control adopts three closed-loop controls of speed, current, and flux, wherein the speed closed-loop control is the outer loop, and the current and flux are the inner loop. By performing closed-loop control on the speed, current, and flux, it is beneficial to enhance the dynamic performance of the system, improve the steady-state performance of the system, improve the anti-interference ability, and expand the speed regulation range.

[0045] Acquiring the real-time flux of the motor includes: acquiring the three-phase current and three-phase voltage of the motor in real time; and calculating the real-time flux of the motor through a flux observer model according to the three-phase current and three-phase voltage. Specifically, by using the state equation of the motor winding, modeling the relationship between voltage and current, and measuring the magnitude and phase difference of the voltage and current, the estimated value of the flux in the motor winding can be calculated.

[0046] The real-time speed ω and real-time position θ of the motor are obtained, including: obtaining the three-phase current and three-phase voltage of the motor; and calculating the real-time speed ω and real-time position θ through a flux observer based on the three-phase current and three-phase voltage. Specifically, the observer is established using the motor flux equation, and the rotor position information (real-time position θ) and real-time speed ω are obtained by calculating and solving the flux change in combination with the current and voltage signals.

[0047] Among them, the above-mentioned flux observer is an algorithm for motor control. It estimates the flux value inside the motor by analyzing the voltage and current signals on the stator side of the motor in real time, and then determines the position and speed information of the rotor. In a permanent magnet synchronous motor, due to the presence of permanent magnets, a constant flux is generated inside the motor, and the flux is directly related to the position of the rotor. The working principle of the flux observer mainly includes: first, the three-phase current signal flowing into the stator winding of the motor and the voltage signal of the three-phase winding are obtained through the current sampling chip or resistor on the hardware circuit of the controller; then coordinate transformation is performed to convert the collected three-phase voltage and current signals into a coordinate system suitable for analysis; then an observer is constructed based on the mathematical model of the motor to estimate the flux value in real time; from the estimated flux signal, the angular position of the rotor relative to the stator (real-time position θ) can be solved, and the speed of the rotor (real-time speed ω) can be estimated. The flux observer is crucial to achieving high-precision FOC. It can replace the physical position sensor, reduce system cost and improve system reliability.

[0048] After the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1 so that the motor runs at the preset speed n1, the method also includes: obtaining the target speed n2; controlling the motor so that the motor runs at the target speed n2. As described above, after the motor is controlled to run at the preset speed n1, the motor will be in a stationary state or a low-speed rotation state, avoiding the danger of the motor running at high speed, and effectively improving the safety of the motor when it is on standby. In this embodiment, after a target speed n2 is given, the motor can be further closed-loop controlled on the basis of the preset speed n1, so that it is finally switched to run at the target speed n2, which can solve the problem of excessive bus voltage rise when the motor is started under the condition of large forward and reverse speeds, resulting in damage to the controller, and ensure the smooth start of the motor.

[0049] Figure 2 FIG. 1 is a schematic diagram of a control process of a fan in a downwind or headwind state using a motor speed control method according to an embodiment of the present invention. Figure 2As shown, when the fan motor is stopped in a downwind or headwind state, the motor will rotate with the wind. When the wind speed is high, the motor speed is also fast, so it is more dangerous and difficult to start. During the startup process, it may also cause bus overvoltage and damage the controller. The motor speed control method of this embodiment controls the motor to short-circuit brake within the T0 time, and the short-circuit braking time is controlled within 150ms, thereby effectively reducing the motor speed. Then a zero current is given, that is, the input D-axis current and Q-axis current are controlled to be 0, and the parameters related to the motor rotation state are obtained. These parameters include: the initial state position θ0 of the motor, the initial speed ω0 and the initial current I0. Then a flux observer is used to perform closed-loop control of the current and flux, with the aim of controlling the speed to n1. Specifically, the speed n1 has a value range of 0rpm to 10rpm. In the process of controlling the motor speed, the bus voltage is monitored in real time, and the input current is limited by a voltage suppression function. Specifically, the voltage suppression function is I limit =k1*ΔU+∫(k2*ΔU)+I0, where k1 is a preset value, K2 is positively correlated with the real-time speed ω, ΔU=U t -U, I0 is the initial value of the input current I. When the voltage suppression function is used to limit the control input current of the motor, if the bus voltage is greater than the threshold, ΔU will be less than 0, and I limit will decrease rapidly; if the bus voltage is not greater than the threshold, I limit It won't get smaller, I limit Saturated output, in addition, I limit Also subject to the current threshold I max , I limit Less than or equal to I max , thus further ensuring the safety of the system. It should be pointed out that when the motor is in the downwind and headwind state, I limit The limiting conditions for the motor control input current are different. In the tailwind state, I limit Limit the lower current limit, that is, control the input current I ≥ limit current I limit ; In the headwind state, I limit Limit the upper limit current, that is, control the input current I≤limit current I limit Through the above-mentioned speed, current, and flux closed-loop control, and through I limit By limiting the control input current, the motor speed can be controlled to the preset speed n1 while ensuring that the busbar is not over-voltaged, so that the motor remains stationary or inching, waiting for the subsequent target speed n2 to be given. This effectively controls the motor to be stationary or in a low speed state in both forward and reverse wind conditions, improving its safety, and is conducive to avoiding busbar overvoltage during motor startup, thereby ensuring normal motor startup, solving the problem of poor safety of motors in high-speed forward and reverse current environments in related technologies.

[0050] Secondly, an embodiment of the present invention further provides a computer program product, which includes computer instructions, and the computer instructions implement the above method when executed by a processor.

[0051] In addition, an embodiment of the present invention further provides a non-volatile storage medium, the non-volatile storage medium includes a stored program, wherein when the program is running, the device where the non-volatile storage medium is located is controlled to execute the above method.

[0052] Again, an embodiment of the present invention further provides a motor controller, which includes a processor, and the processor is used to run a program, and the above method is executed when the program is running.

[0053] Finally, an embodiment of the present invention further provides a three-phase motor, which includes a motor body and a motor controller electrically connected thereto, and the motor controller controls the operation of the motor body, wherein the motor controller is the above-mentioned motor controller.

[0054] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments. Moreover, the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in a different order than here.

[0055] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0056] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0057] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0058] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0059] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A motor speed control method, characterized in that: include: Controlling the motor to perform short-circuit braking for a preset time, wherein the preset time is less than or equal to 150ms; Control the D-axis current and Q-axis current of the motor to be 0, and obtain the real-time rotation speed ω and real-time position θ of the motor; According to the real-time position θ, the real-time rotational speed ω and the preset rotational speed n1, the motor is closed-loop controlled so that the motor runs at the preset rotational speed n1, wherein the value range of n1 is 0 rpm to 10 rpm.

2. The method according to claim 1, characterized in that According to the real-time position θ, the real-time speed ω and the preset speed n1, the motor is closed-loop controlled, including: At least according to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit ; According to the limiting current I limit , the input current I is limited so that when the bus voltage U is greater than the preset voltage threshold U t , the bus voltage U is reduced, wherein the input current I is used to control the action of the motor, and the input current I=(I d 2 +I q 2 ) 1 / 2 , I d is the D-axis current of the input motor, I q is the Q axis current of the motor input.

3. The method according to claim 2, characterized in that According to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit ,include: When the bus voltage U is greater than the preset voltage threshold U t In the case of controlling the limiting current I limit Reduce.

4. The method according to claim 2, characterized in that: According to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit ,include: Determine the limiting current I limit =k1*ΔU+∫(k2*ΔU)+I0, where k1 is a preset value, K2 is positively correlated with the real-time speed ω, ΔU=U t -U, I0 is the initial value of the input current I.

5. The method according to claim 4, characterized in that According to the bus voltage U and the preset voltage threshold U t , determine the limiting current I limit , also includes: In determining the limiting current I limit Greater than the current threshold I max In the case of controlling the limiting current I limit decreases, so that the limiting current I limit Less than or equal to the current threshold I max , wherein the current threshold I max is the default value.

6. The method according to claim 4, characterized in that According to the limiting current I limit , limit the input current I, including: determining a rotation direction of the motor; When the motor rotates in the forward direction, the input current I is controlled to be greater than or equal to the limiting current I limit ; When the motor rotates in reverse, the input current I is controlled to be less than the limiting current I limit .

7. The method according to claim 2, characterized in that According to the limiting current I limit , before limiting the magnitude of the input current I, performing closed-loop control on the motor according to the real-time position θ, the real-time speed ω and the preset speed n1, further comprising: Calculate a target torque according to the real-time position θ, the real-time speed ω and the preset speed n1, wherein the target torque is used to drive the motor to adjust from the real-time speed ω to the preset speed n1; According to the target torque, determining a given current and a given flux corresponding thereto; According to the given current and the given flux, a D-axis current and a Q-axis current input to the motor are determined.

8. The method according to claim 7, characterized in that Determining the real-time rotation speed of the D-axis current and the Q-axis current input to the motor according to the given current and the given flux linkage includes: Acquire the real-time current of the motor, and perform closed-loop control on the real-time current according to the given current, wherein the real-time current is the real-time three-phase current of the motor; Acquiring the real-time flux of the motor, and performing closed-loop control on the real-time flux according to the given flux; The D-axis current and the Q-axis current are determined based on the closed-loop control of the real-time current and the closed-loop control of the real-time flux.

9. The method according to claim 8, characterized in that Obtaining the real-time flux of the motor, including: Acquire the three-phase current and three-phase voltage of the motor in real time; According to the three-phase current and the three-phase voltage, the real-time flux of the motor is calculated by a flux observer model.

10. The method according to claim 1, characterized in that Obtaining the real-time speed ω and real-time position θ of the motor includes: Obtaining three-phase current and three-phase voltage of the motor; Based on the three-phase current and the three-phase voltage, the real-time rotation speed ω and the real-time position θ are calculated by a flux observer.

11. The method according to claim 1, characterized in that: After the motor is closed-loop controlled according to the real-time position θ, the real-time speed ω and the preset speed n1 so that the motor runs at the preset speed n1, the method further comprises: Get the target speed n2; The motor is controlled so as to operate at the target speed n2.

12. A computer program product, characterized in that The method comprises computer instructions, which implement the method according to any one of claims 1 to 11 when executed by a processor.

13. A non-volatile storage medium, characterized in that: The non-volatile storage medium includes a stored program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute the method according to any one of claims 1 to 11.

14. A motor controller, characterized in that: The method comprises a processor, wherein the processor is used to run a program, and the program executes the method according to any one of claims 1 to 11 when running.

15. A three-phase motor, characterized in that: The three-phase motor includes a motor body and a motor controller electrically connected thereto, wherein the motor controller controls the operation of the motor body, wherein the motor controller is the motor controller according to claim 14.

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