Method and device for controlling asynchronous motor, asynchronous motor controller and storage medium

Abstract

The application is suitable for the technical field of asynchronous motor control, and provides an asynchronous motor control method and device, an asynchronous motor controller and a storage medium. The first magnetic chain of the kth period is obtained according to the stator phase voltage and the stator phase current of the kth period and the first magnetic chain and the second magnetic chain of the k-1th period; the second magnetic chain of the kth period is obtained according to the stator phase current of the kth period and the speed, the first magnetic chain and the second magnetic chain of the k-1th period; the speed of the kth period is obtained according to the error between the first magnetic chain and the second magnetic chain of the kth period and the stator phase current of the kth period; the third magnetic chain of the kth period is obtained according to the first magnetic chain and the second magnetic chain of the kth period; the magnetic chain angle of the kth period is obtained according to the third magnetic chain of the kth period; and the asynchronous motor is feedback controlled in the k+1th period according to the magnetic chain angle and the speed of the kth period, so that the magnetic chain angle and the speed of the asynchronous motor can be accurately estimated.

Description

Technical Field

[0001] This application belongs to the field of asynchronous motor control technology, and in particular relates to an asynchronous motor control method, device, asynchronous motor controller and storage medium. Background Technology

[0002] With the development of power electronics and AC motor drive technologies, variable speed drive systems composed of frequency converters and AC motors have been widely used in rail transportation, electric vehicles, machining, and home appliances. Asynchronous motors (also known as induction motors) in AC motors have become widely used transmission devices in variable speed drive systems due to their advantages such as low cost, high reliability, and ease of maintenance.

[0003] In asynchronous motor drive systems, closed-loop speed control typically requires a speed sensor (e.g., an encoder) mounted on the motor shaft to detect motor speed. The introduction of a speed sensor increases cost, reduces system reliability, and in certain special environments (e.g., high-temperature, high-humidity, dusty workshops and mines), speed sensors cannot be installed. Therefore, accurately estimating the flux linkage and speed of a sensorless asynchronous motor control system has become a pressing problem. Summary of the Invention

[0004] This application provides an asynchronous motor control method, device, asynchronous motor controller, and storage medium to solve the problem that existing asynchronous motor control systems without speed sensors have difficulty accurately estimating flux linkage and rotational speed.

[0005] The first aspect of this application provides an asynchronous motor control method, including:

[0006] The first magnetic flux linkage in the k-th period is obtained based on the stator phase voltage and stator phase current in the k-th period, as well as the first magnetic flux linkage in the (k-1)-th period and the second magnetic flux linkage in the (k-1)-th period.

[0007] The second magnetic flux linkage in the k-th cycle is obtained based on the stator phase current in the k-th cycle, the rotational speed in the (k-1)-th cycle, the first magnetic flux linkage in the (k-1)-th cycle, and the second magnetic flux linkage in the (k-1)-th cycle.

[0008] The rotational speed in the k-th cycle is obtained based on the error between the first magnetic flux linkage and the second magnetic flux linkage in the k-th cycle, and the stator phase current in the k-th cycle.

[0009] Based on the first magnetic flux linkage of the kth period and the second magnetic flux linkage of the kth period, the third magnetic flux linkage of the kth period is obtained;

[0010] Based on the third magnetic flux of the kth period, the magnetic flux angle of the kth period is obtained;

[0011] Based on the flux linkage angle and rotational speed of the kth cycle, feedback control is performed on the asynchronous motor in the (k+1)th cycle.

[0012] Where k is any positive integer.

[0013] A second aspect of this application provides an asynchronous motor control device, comprising:

[0014] The first flux linkage estimation unit is used to obtain the first flux linkage of the k-th period based on the stator phase voltage and stator phase current of the k-th period, as well as the first flux linkage of the (k-1)-th period and the second flux linkage of the (k-1)-th period.

[0015] The second flux linkage estimation unit is used to obtain the second flux linkage in the k-th period based on the stator phase current in the k-th period, the rotational speed in the (k-1)-th period, the first flux linkage in the (k-1)-th period, and the second flux linkage in the (k-1)-th period.

[0016] The rotational speed estimation unit is used to obtain the rotational speed of the k-th cycle based on the error between the first magnetic flux linkage and the second magnetic flux linkage of the k-th cycle, and the stator phase current of the k-th cycle.

[0017] The third flux linkage estimation unit is used to obtain the third flux linkage of the k-th period based on the first flux linkage of the k-th period and the second flux linkage of the k-th period.

[0018] A flux linkage angle estimation unit is used to obtain the flux linkage angle of the k-th period based on the third flux linkage of the k-th period.

[0019] A feedback control unit is used to perform feedback control on the asynchronous motor in the (k+1)th cycle based on the flux linkage angle and the rotational speed in the kth cycle.

[0020] Where k is any positive integer.

[0021] A third aspect of this application provides an asynchronous motor controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the asynchronous motor control method described in the first aspect of this application.

[0022] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the asynchronous motor control method described in the first aspect of this application.

[0023] The asynchronous motor control method provided in the first aspect of this application obtains the first flux linkage of the k-th cycle based on the stator phase voltage and stator phase current of the k-th cycle, and the first and second flux linkages of the (k-1)-th cycle; obtains the second flux linkage of the k-th cycle based on the stator phase current of the k-th cycle, and the rotational speed, first flux linkage, and second flux linkage of the (k-1)-th cycle; obtains the rotational speed of the k-th cycle based on the error between the first and second flux linkages of the k-th cycle and the stator phase current of the k-th cycle; obtains the third flux linkage of the k-th cycle based on the first and second flux linkages of the k-th cycle; obtains the flux linkage angle of the k-th cycle based on the third flux linkage of the k-th cycle; and performs feedback control on the asynchronous motor in the (k+1)-th cycle based on the flux linkage angle and rotational speed of the k-th cycle. This method can accurately estimate the flux linkage angle and rotational speed of the asynchronous motor, and performs feedback control on the asynchronous motor based on the estimated values ​​of the flux linkage angle and rotational speed. It has high control accuracy and reliability, and is applicable to asynchronous motor control systems with and without speed sensors.

[0024] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the asynchronous motor control method provided in an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the logic structure of the asynchronous motor control device provided in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the logic structure of the first asynchronous motor control system provided in the embodiments of this application;

[0029] Figure 4 This is a schematic diagram of the logic structure of the second asynchronous motor control system provided in the embodiments of this application;

[0030] Figure 5 This is a schematic diagram of the asynchronous motor controller provided in the embodiments of this application. Detailed Implementation

[0031] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0032] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0033] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0034] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0035] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0037] This application provides an asynchronous motor control method that can be executed by the processor of the asynchronous motor controller when running the corresponding computer program. It can accurately estimate the flux linkage angle and speed of the asynchronous motor, and perform feedback control on the asynchronous motor based on the estimated values ​​of flux linkage angle and speed. It has high control accuracy and reliability, and is applicable to asynchronous motor control systems with and without speed sensors.

[0038] In applications, motor controllers can be used in rail transit, electric vehicles, machining, and home appliances. Home appliances can include air conditioners, fans, washing machines, refrigerators, etc., and motor controllers can specifically be frequency converters.

[0039] In applications, the principle by which a motor controller controls the rotation of an asynchronous motor is as follows:

[0040] The motor controller includes a current sensor, an inverter, and a processor;

[0041] The current sensor is electrically connected to the negative terminal of the DC bus and is used to detect the bus current on the DC bus. The current sensor can be implemented by a sampling resistor connected in series with the negative terminal of the DC bus.

[0042] The first input terminal of the inverter is electrically connected to the positive terminal of the DC bus, and the second input terminal of the inverter is electrically connected to the negative terminal of the DC bus. The inverter may include a two-phase bridge arm or a three-phase bridge arm.

[0043] When the inverter includes a two-phase bridge arm, the four controlled terminals of the inverter are electrically connected to the processor, and the two output terminals of the inverter are electrically connected to the two phase current and phase voltage input terminals of the two-phase asynchronous motor, respectively.

[0044] When the inverter includes a three-phase bridge arm, the six controlled terminals of the inverter are electrically connected to the processor, and the three output terminals of the inverter are electrically connected to the three phase current and phase voltage input terminals of the three-phase asynchronous motor, respectively.

[0045] Each phase arm of the inverter includes two switching transistors (upper switching transistor and lower switching transistor). The input terminals of all upper switching transistors are connected together to form the first input terminal of the inverter, and the output terminals of all lower switching transistors are connected together to form the second input terminal of the inverter. The controlled terminal of each switching transistor forms a controlled terminal of the inverter, and the output terminal of the upper switching transistor and the input terminal of the lower switching transistor of each phase arm are connected together to form an output terminal of the inverter.

[0046] The processor is used for:

[0047] To obtain the stator phase voltage that needs to be applied to the stator to achieve the target speed of the asynchronous motor, so as to generate the corresponding stator phase current in the stator;

[0048] The Space Vector Pulse Width Modulation (SVPWM) method is employed. Based on the rotor angle and the target stator phase voltage, the target voltage vector is determined. Then, based on the magnitude and phase angle of the target voltage vector, a comparison value is obtained through a comparison value calculation method based on SVPWM. A triangular carrier wave is then used to compare the calculated comparison value to generate a pulse width modulation (PWM) signal for driving the inverter. The PWM signal controls the on / off state of the inverter's switching transistors, thereby making the actual voltage of the bus voltage acting on the stator equivalent to the target stator phase voltage. Correspondingly, the actual current of the bus current acting on the stator is equivalent to the target stator phase current, which in turn causes the stator to generate a corresponding magnetic field to drive the rotor to rotate at the target speed.

[0049] To improve the control accuracy of asynchronous motors, it is necessary to collect the bus current on the DC bus using a current sensor to obtain its magnitude. Based on this bus current magnitude, the magnitude of the actual stator phase current applied to the stator can be estimated. By comparing the actual stator phase current with the target stator phase current, the target stator phase current can be adjusted according to the deviation between the two. Based on the adjusted target stator phase current, the adjusted target stator phase voltage can be obtained. Combining this with the space vector pulse width modulation method, the adjusted target voltage vector can be determined. Then, an adjusted pulse width modulation signal is generated based on the adjusted target voltage vector, and the on / off state of the inverter's switching transistors is controlled according to the adjusted pulse width modulation signal, ultimately achieving feedback control of the asynchronous motor.

[0050] In applications, the switching transistor has the function of turning on or off under the trigger of a PWM signal, and is used as an electronic switch. Specifically, it can be an Insulated Gate Bipolar Transistor (IGBT), or it can be a Bipolar Junction Transistor (BJT), a Field Effect Transistor (FET), a Thyristor, etc. An IGBT is a composite fully controllable voltage-driven power semiconductor device composed of a bipolar transistor and an insulated gate field effect transistor. It combines the advantages of the high input impedance of the insulated gate field effect transistor and the low on-state voltage drop of the bipolar transistor. The field effect transistor can be a Metal-Oxide Semiconductor Field Effect Transistor (MOS-FET).

[0051] like Figure 1As shown, the asynchronous motor control method provided in this application includes the following steps S101 to S106:

[0052] Step S101: Based on the stator phase voltage and stator phase current of the kth period, as well as the first magnetic flux linkage of the (k-1)th period and the second magnetic flux linkage of the (k-1)th period, obtain the first magnetic flux linkage of the kth period, and proceed to steps S103 and S104.

[0053] Step S102: Based on the stator phase current of the k-th cycle, the rotational speed of the (k-1)-th cycle, the first magnetic flux linkage of the (k-1)-th cycle, and the second magnetic flux linkage of the (k-1)-th cycle, obtain the second magnetic flux linkage of the k-th cycle, and proceed to steps S103 and S104.

[0054] In application, k is any positive integer, and the k-th period can be any asynchronous motor control period. For example, the k-th period can be the current asynchronous motor control period, and the (k-1)-th period is the previous asynchronous motor control period. When k is 1, the k-th period is the 1st asynchronous motor control period, and the (k-1)-th period is the 0th asynchronous motor control period. The 0th asynchronous motor control period is when the periodic control of the asynchronous motor has not yet started. Therefore, the speed, first flux linkage, and second flux linkage in the 0th asynchronous motor control period can be 0 or preset values ​​according to actual needs. For asynchronous motors equipped with speed sensors, the speed in the 0th asynchronous motor control period can also be detected by the speed sensor.

[0055] In applications, the stator phase current can be detected by the motor phase current reconstruction method based on current sensors and single bus current detection technology, and the stator phase voltage can be calculated by conversion based on the stator phase current.

[0056] In application, the principle for obtaining the first flux linkage of the k-th cycle is the same as that for obtaining the first flux linkage of the k-1-th cycle. The first flux linkage of the k-1-th cycle is obtained based on the stator phase voltage and stator phase current of the k-1-th cycle, as well as the first flux linkage of the k-2-th cycle and the second flux linkage of the k-2-th cycle. Similarly, the principle for obtaining the second flux linkage of the k-th cycle is the same as that for obtaining the second flux linkage of the k-th cycle. The second flux linkage of the k-1-th cycle is obtained based on the stator phase current of the k-1-th cycle, as well as the rotational speed of the k-2-th cycle, the first flux linkage of the k-2-th cycle, and the second flux linkage of the k-2-th cycle.

[0057] In one embodiment, step S101 includes:

[0058] The first flux linkage of the k-th period is obtained from the stator phase voltage, stator phase current, rotor inductance, mutual inductance, total leakage inductance, and stator resistance of the k-th period, as well as the first flux linkage and the second flux linkage of the (k-1)-th period.

[0059] In application, the first flux linkage of the k-th cycle is specifically obtained based on the stator phase voltage, stator phase current, rotor inductance, mutual inductance, total leakage inductance and stator resistance of that cycle, as well as the first flux linkage of the (k-1)-th cycle and the second flux linkage of the (k-1)-th cycle.

[0060] In one embodiment, the formula for calculating the first magnetic flux linkage in the k-th period is:

[0061]

[0062]

[0063] Where p represents the differentiation operator. Let L represent the α-axis component and β-axis component of the first flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. r，k L m，k L σ，k R s，k Let v represent the rotor inductance, mutual inductance, total leakage inductance, and stator resistance in the k-th cycle, respectively. sα，k v sβ，k Let i represent the α-axis component and β-axis component of the stator phase voltage in the k-th period in the two-phase stationary coordinate system, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively. Let α and β represent the first magnetic flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K1 represent the α-axis and β-axis components of the second flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively, and let K1 represent the first feedback matrix. 1α k 1β This represents the feedback coefficient of the first feedback matrix.

[0064] In one embodiment, step S102 includes:

[0065] The second flux linkage in the k-th period is obtained based on the stator phase current in the k-th period, the mutual inductance in the k-th period, the rotor time constant in the k-th period, the rotational speed in the (k-1)-th period, the first flux linkage in the (k-1)-th period, and the second flux linkage in the (k-1)-th period.

[0066] In application, the second flux linkage of the k-th cycle is specifically obtained based on the stator phase current, mutual inductance, and rotor time constant of that cycle, as well as the rotational speed of the (k-1)-th cycle, the first flux linkage of the (k-1)-th cycle, and the second flux linkage of the (k-1)-th cycle.

[0067] In one embodiment, the formula for calculating the second magnetic flux linkage in the k-th period is:

[0068]

[0069]

[0070] Where p represents the differentiation operator. Let α and β represent the components of the second magnetic flux in the k-th period in the two-phase stationary coordinate system, respectively. L represents the rotational speed in the (k-1)th cycle. m，k τ r，k Let i represent the mutual inductance in the k-th period and the rotor time constant in the k-th period, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively. Let α and β represent the first magnetic flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K1 and K2 represent the α-axis and β-axis components of the second flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K2 represent the second feedback matrix. 2α k 2β This represents the feedback coefficient of the second feedback matrix.

[0071] In applications, the rotor time constant of an asynchronous motor can be calculated based on the mutual inductance of the asynchronous motor, and the first feedback matrix and the second feedback matrix are feedback gain matrices.

[0072] In application, the principle for obtaining the first flux linkage in the k-th cycle is the same as that for the (k-1)-th cycle. Specifically, the first flux linkage in the (k-1)-th cycle is obtained based on the stator phase voltage, stator phase current, rotor inductance, mutual inductance, total leakage inductance, and stator resistance of that cycle, as well as the first flux linkage in the (k-2)-th cycle and the second flux linkage in the (k-2)-th cycle. Similarly, the principle for obtaining the second flux linkage in the k-th cycle is the same as that for the (k-1)-th cycle. Specifically, the second flux linkage in the (k-1)-th cycle is obtained based on the stator phase current, mutual inductance, and rotor time constant of that cycle, as well as the rotational speed, the first flux linkage in the (k-2)-th cycle, and the second flux linkage in the (k-2)-th cycle. Since the 0th asynchronous motor control cycle is before the periodic control of the asynchronous motor begins, all parameters required for the 0th asynchronous motor control cycle can be 0 or pre-set values ​​according to actual needs.

[0073] In application, the formula for calculating the first magnetic flux linkage is the expression of the first magnetic flux linkage calculation model, and the formula for calculating the second magnetic flux linkage is the expression of the second magnetic flux linkage calculation model. The calculation process of the first magnetic flux linkage in the k-th period requires the first magnetic flux linkage obtained based on the first magnetic flux linkage calculation model and the second magnetic flux linkage obtained based on the second magnetic flux linkage calculation model in the (k-1)-th period. Correspondingly, the calculation process of the second magnetic flux linkage in the k-th period also requires the first magnetic flux linkage obtained based on the first magnetic flux linkage calculation model and the second magnetic flux linkage obtained based on the second magnetic flux linkage calculation model in the (k-1)-th period.

[0074] Step S103: Based on the error between the first magnetic flux linkage and the second magnetic flux linkage in the kth period, and the stator phase current in the kth period, obtain the rotational speed in the kth period, and proceed to step S106.

[0075] In application, after obtaining the estimated values ​​of the first and second flux linkages for the k-th cycle, the error between these estimates can be calculated. This error is then cross-multiplied or dot-multiplied with the stator phase current, and finally integrated to obtain an estimate of the asynchronous motor's speed based on a speed adaptive mechanism. The integration operation can be implemented using an integrator or a proportional-integrator.

[0076] In one embodiment, step S103 includes:

[0077] The error between the first magnetic flux linkage and the second magnetic flux linkage in the k-th period is cross-multiplied with the stator phase current in the k-th period to obtain the first input value;

[0078] Integrate the first input value to obtain the rotational speed in the kth cycle;

[0079] Alternatively, the error between the first magnetic flux linkage and the second magnetic flux linkage in the kth period can be multiplied by the stator phase current in the kth period to obtain the second input value.

[0080] Integrate the second input value to obtain the rotational speed of the kth cycle.

[0081] In application, the first input value is the value obtained by cross-productting the error between the estimated values ​​of the first and second flux linkages with the stator phase current, and is used as the input parameter of the integrator or proportional-integral unit. The second input value is the value obtained by dot-productting the error between the estimated values ​​of the first and second flux linkages with the stator phase current, and is used as the input parameter of the integrator or proportional-integral unit.

[0082] In one embodiment, the formula for calculating the first input value is:

[0083]

[0084] The formula for calculating the second input value is:

[0085]

[0086] in, The transpose of the error between the first flux linkage in period k and the second flux linkage in period k is given by i. s，k This represents the stator phase current in the k-th period. Let α and β represent the first magnetic flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. Let i represent the α-axis component and β-axis component of the second flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively.

[0087] Step S104: Based on the first magnetic flux linkage of the kth period and the second magnetic flux linkage of the kth period, obtain the third magnetic flux linkage of the kth period, and proceed to step S105.

[0088] In application, after obtaining the estimated values ​​of the first and second flux linkages for the k-th period, these values ​​can be further fused to obtain the estimated value of the third flux linkage for the k-th period. In each asynchronous motor control cycle, the estimated values ​​of the first and second flux linkages can be weighted and averaged or filtered to obtain the estimated value of the third flux linkage. The estimated values ​​of the first and second flux linkages are the initial flux linkage estimates, and the third flux linkage is the final flux linkage estimate.

[0089] In one embodiment, step S104 includes:

[0090] The third magnetic flux of the k-th period is obtained by taking a weighted average of the first magnetic flux and the second magnetic flux of the k-th period.

[0091] Alternatively, a high-pass filter can be applied to one of the first magnetic flux linkage and the second magnetic flux linkage in the k-th period, and a low-pass filter can be applied to the other to obtain the third magnetic flux linkage in the k-th period.

[0092] In one embodiment, the formula for calculating the third magnetic flux in the k-th period is:

[0093]

[0094] in, Let f1 and f2 represent the third, first, and second magnetic flux linkages of the k-th period, respectively. Let f1 and f2 represent the sub-functions of the weighted average function corresponding to the weighting coefficients 1-m and m, respectively, where 0 ≤ m ≤ 1. Alternatively, one of f1 and f2 can represent a high-pass filter function and the other a low-pass filter function.

[0095] In one embodiment, f1 and f2 represent the sub-functions of the weighted average function corresponding to the weighting coefficients 1-m and k, respectively, where 0 ≤ m ≤ 1. The formula for calculating the third magnetic flux linkage in the k-th period is:

[0096] Step S105: Obtain the magnetic flux angle of the k-th period based on the third magnetic flux of the k-th period, and proceed to step S106.

[0097] In applications, after obtaining the estimated value of the third flux linkage, the estimated value of the flux linkage angle is further obtained based on the estimated value of the third flux linkage. The estimated value of the third flux linkage can be input into the phase-locked loop (PLL) to obtain the estimated value of the flux linkage angle output by the PLL; alternatively, the estimated value of the flux linkage angle can be obtained by taking the inverse tangent of the α-axis and β-axis components of the estimated value of the third flux linkage in a two-phase stationary coordinate system.

[0098] In one embodiment, step S105 includes:

[0099] The flux linkage angle of the k-th period is obtained by using a phase-locked loop based on the third flux linkage of the k-th period;

[0100] Alternatively, the inverse tangent values ​​of the α-axis and β-axis components of the third flux linkage in the k-th period can be obtained to get the flux linkage angle in the k-th period.

[0101] In one embodiment, the formula for calculating the flux linkage angle of the kth period is:

[0102]

[0103] in, tan represents the flux linkage angle in the k-th period. -1 Represents the inverse tangent function. Let α and β represent the α-axis components and β-axis components of the third flux linkage in the k-th period in the two-phase stationary coordinate system, respectively.

[0104] Step S106: Based on the flux linkage angle and rotational speed of the kth cycle, perform feedback control on the asynchronous motor in the (k+1)th cycle.

[0105] In application, the motor controller adjusts the stator phase voltage that needs to be applied to the stator in the next cycle based on the estimated values ​​of flux linkage angle and speed obtained in the current cycle, thereby providing feedback control for the actual speed of the asynchronous motor in the next cycle.

[0106] In one embodiment, after step S103 and before step S106, the method further includes:

[0107] The rotational speed in the kth cycle is subjected to low-pass filtering.

[0108] In applications, before the motor controller performs feedback control on the asynchronous motor based on the estimated speed, a low-pass filter can be used to filter out high-frequency interference signals, thereby improving the control accuracy and reliability of the asynchronous motor.

[0109] It should be understood that the flux linkage in the embodiments of this application refers to the rotor flux linkage. The (k-1)th cycle, the kth cycle, and the (k+1)th cycle can also be three consecutive time periods within an asynchronous motor control cycle. Alternatively, the (k-1)th cycle and the kth cycle can be combined into a longer cycle, making the (k-1)th cycle, the kth cycle, and the (k+1)th cycle equivalent to two cycles, where the duration of one cycle is equal to the sum of the durations of the (k-1)th cycle and the kth cycle. For any cycle, if parameters from the previous cycle are needed when calculating the parameters of that cycle, these parameters can be obtained from the previous cycle or pre-set values ​​according to actual needs can be used directly, thus eliminating the need to wait for a cycle to obtain the parameters.

[0110] The asynchronous motor control method provided in this application obtains an estimated value of the first flux linkage for the current cycle based on the stator phase voltage and stator phase current of the current cycle, as well as the estimated values ​​of the first flux linkage and the second flux linkage of the previous cycle; it obtains an estimated value of the second flux linkage for the current cycle based on the stator phase current of the current cycle, as well as the estimated values ​​of the rotational speed, the first flux linkage, and the second flux linkage of the previous cycle; and it obtains an estimated value of the second flux linkage for the current cycle based on the relationship between the estimated values ​​of the first flux linkage and the estimated values ​​of the second flux linkage for the current cycle. Based on the error and the stator phase current of the current cycle, the estimated value of the rotational speed of the current cycle is obtained; based on the estimated values ​​of the first flux linkage and the second flux linkage of the current cycle, the estimated value of the third flux linkage of the current cycle is obtained; based on the estimated value of the third flux linkage of the current cycle, the estimated value of the flux linkage angle of the current cycle is obtained; finally, based on the estimated values ​​of the flux linkage angle and the rotational speed of the current cycle, feedback control is performed on the rotational speed of the asynchronous motor in the next cycle. The control accuracy and reliability are high, and it is applicable to asynchronous motor control systems with and without speed sensors.

[0111] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0112] This application also provides an asynchronous motor control device, applied to an asynchronous motor controller, for executing the method steps described in the above method embodiments. This device can be a virtual appliance within the asynchronous motor controller, run by the asynchronous motor controller's processor, or it can be the asynchronous motor controller itself.

[0113] like Figure 2 As shown, the asynchronous motor control device 100 provided in this application embodiment includes:

[0114] The first flux linkage estimation unit 101 is used to obtain the first flux linkage of the k-th period based on the stator phase voltage and stator phase current of the k-th period, as well as the first flux linkage of the (k-1)-th period and the second flux linkage of the (k-1)-th period, and then enter the speed estimation unit 103 and the third flux linkage estimation unit 104.

[0115] The second flux linkage estimation unit 102 is used to obtain the second flux linkage of the k-th period based on the stator phase current of the k-th period, the rotational speed of the (k-1)-th period, the first flux linkage of the (k-1)-th period, and the second flux linkage of the (k-1)-th period, and then enter the rotational speed estimation unit 103 and the third flux linkage estimation unit 104.

[0116] The rotational speed estimation unit 103 is used to obtain the rotational speed of the k-th cycle based on the error between the first magnetic flux and the second magnetic flux of the k-th cycle, and the stator phase current of the k-th cycle, and then input it into the feedback control unit 106.

[0117] The third flux linkage estimation unit 104 is used to obtain the third flux linkage of the k-th period based on the first flux linkage of the k-th period and the second flux linkage of the k-th period, and then enter the flux linkage angle estimation unit 105.

[0118] The flux linkage angle estimation unit 105 is used to obtain the flux linkage angle of the k-th period based on the third flux linkage of the k-th period, and then input it into the feedback control unit 106.

[0119] The feedback control unit 106 is used to perform feedback control on the asynchronous motor in the (k+1)th cycle based on the flux linkage angle and the rotational speed in the kth cycle.

[0120] Where k is any positive integer.

[0121] In one embodiment, the asynchronous motor control device further includes:

[0122] A low-pass filter unit is used to perform low-pass filtering on the rotational speed of the k-th cycle.

[0123] In applications, the components in the above-mentioned device can be software program units, or they can be implemented through different logic circuits integrated in a processor or independent physical components connected to the processor, or they can be implemented through multiple distributed processors. For example, the first flux linkage estimation unit and the second flux linkage estimation unit can each include a subtractor or share a subtractor; the speed estimation unit can include a subtractor, a multiplier, and an integrator or proportional-integral unit; the flux linkage angle estimation unit can be a phase-locked loop; the feedback control unit can be a feedback controller; and the low-pass filtering unit can be a low-pass filter.

[0124] like Figure 3 As shown, an exemplary schematic diagram of the logic structure of a first asynchronous motor control system is illustrated, which includes a first feedback gain matrix 201, a second feedback gain matrix 202, a first flux linkage calculation model 203, a second flux linkage calculation model 204, a first subtractor 205, a proportional-integral unit 206, a multiplier 207, a third flux linkage estimation unit 208, a flux linkage angle estimation unit 209, a feedback control unit 210, and an asynchronous motor 211.

[0125] like Figure 4 As shown, an exemplary schematic diagram of the logic structure of a second asynchronous motor control system is presented, which, based on the first asynchronous motor control system, further includes a speed sensor 212, a first switching switch 213, and a second switching switch 214.

[0126] In applications, both the first and second switching switches are used to implement a two-to-one selection function, which can be achieved through software program units, electronic switching transistors, or logic gate circuits.

[0127] like Figure 5 As shown, this application embodiment also provides an asynchronous motor controller 300, including: at least one processor 301 ( Figure 5 The diagram shows only one processor, memory 302, and computer program 303 stored in memory 302 and executable on at least one processor 302. When processor 302 executes computer program 303, it implements the steps in the above-described embodiments of asynchronous motor control methods.

[0128] In applications, asynchronous motor controllers may include, but are not limited to, processors and memory, and may also include current sensors, inverters, rectifiers, analog-to-digital converters, high-pass filters, low-pass filters, subtractors, integrators, proportional-integral converters, phase-locked loops, switching devices, etc. Those skilled in the art will understand that... Figure 5This is merely an example of an asynchronous motor controller and does not constitute a limitation on asynchronous motor controllers. It may include more or fewer components than illustrated, or combine certain components, or use different components. For example, it may also include input / output devices, network access devices, etc. The network access device may include a communication module for communication between the asynchronous motor controller and the user terminal.

[0129] In applications, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0130] In applications, the memory may be an internal storage unit of the asynchronous motor controller in some embodiments, such as the hard drive or RAM of the asynchronous motor controller. In other embodiments, the memory may be an external storage device of the asynchronous motor controller, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. The memory may also include both internal and external storage units of the asynchronous motor controller. The memory is used to store the operating system, applications, boot loader, data, and other programs, such as the program code of a computer program. The memory can also be used to temporarily store data that has been output or will be output.

[0131] In applications, the communication module can be configured as any device capable of long-distance wired or wireless communication with clients, directly or indirectly, according to actual needs. For example, the communication module can provide solutions for communication applications on network devices, including Wireless Local Area Networks (WLANs) (such as Wi-Fi networks), Bluetooth, Zigbee, mobile communication networks, Global Navigation Satellite System (GNSS), Frequency Modulation (FM), Near Field Communication (NFC), and Infrared (IR) technologies. The communication module can include an antenna, which can have a single element or be an antenna array with multiple elements. The communication module can receive electromagnetic waves through the antenna, frequency modulate and filter the electromagnetic wave signal, and send the processed signal to the processor. The communication module can also receive signals to be transmitted from the processor, frequency modulate and amplify them, and then convert them into electromagnetic waves for radiation via the antenna.

[0132] In applications, low-pass filters can be selected according to actual needs, using any type of filter with a cutoff frequency that meets the requirements, such as Butterworth filters or Chebyshev filters.

[0133] In applications, analog-to-digital converters (ADCs) can be selected based on actual needs, choosing any type of ADC with the required sampling accuracy, such as parallel comparator, successive approximation, or dual-slope ADCs. The sampling accuracy of an ADC is determined by its resolution, which can be selected according to actual requirements, such as eight-bit, twelve-bit, or twenty-four-bit. When using a resolution-switching ADC, users can switch the ADC resolution via an asynchronous motor controller or a user terminal's human-machine interface to adapt to different application scenarios.

[0134] It should be noted that the information interaction and execution process between the above-mentioned devices / modules are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0135] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional modules is merely an example. In practical applications, the functions described above can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The functional modules in the embodiments can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules can be implemented in hardware or as software functional modules. Furthermore, the specific names of the functional modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0136] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps in the above-described method embodiments.

[0137] This application provides a computer program product that, when run on an asynchronous motor controller, enables the asynchronous motor controller to implement the steps described in the above-described method embodiments.

[0138] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate form. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to the asynchronous motor controller, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, such as a USB flash drive, a portable hard drive, a magnetic disk, or an optical disk.

[0139] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0140] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0141] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0142] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0143] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An asynchronous motor control method, characterized in that, include: The first magnetic flux linkage in the k-th period is obtained based on the stator phase voltage and stator phase current in the k-th period, as well as the first magnetic flux linkage in the (k-1)-th period and the second magnetic flux linkage in the (k-1)-th period. The second magnetic flux linkage in the k-th cycle is obtained based on the stator phase current in the k-th cycle, the rotational speed in the (k-1)-th cycle, the first magnetic flux linkage in the (k-1)-th cycle, and the second magnetic flux linkage in the (k-1)-th cycle. The rotational speed in the k-th cycle is obtained based on the error between the first magnetic flux linkage and the second magnetic flux linkage in the k-th cycle, and the stator phase current in the k-th cycle. Based on the first magnetic flux linkage of the kth period and the second magnetic flux linkage of the kth period, the third magnetic flux linkage of the kth period is obtained; Based on the third magnetic flux of the kth period, the magnetic flux angle of the kth period is obtained; Based on the flux linkage angle and rotational speed of the kth cycle, feedback control is performed on the asynchronous motor in the (k+1)th cycle. Where k is any positive integer.

2. The asynchronous motor control method as described in claim 1, characterized in that, The step of obtaining the first magnetic flux linkage in the k-th period based on the stator phase voltage and stator phase current in the k-th period, as well as the first magnetic flux linkage and the second magnetic flux linkage in the (k-1)-th period, includes: The first flux linkage of the k-th period is obtained from the stator phase voltage, stator phase current, rotor inductance, mutual inductance, total leakage inductance, and stator resistance of the k-th period, as well as the first flux linkage and the second flux linkage of the (k-1)-th period.

3. The asynchronous motor control method as described in claim 2, characterized in that, The formula for calculating the first magnetic flux linkage in the k-th period is: Where p represents the differentiation operator. Let L represent the α-axis component and β-axis component of the first flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. r，k L m，k L σ，k R s，k Let v represent the rotor inductance, mutual inductance, total leakage inductance, and stator resistance in the k-th cycle, respectively. sα，k v sβ，k Let i represent the α-axis component and β-axis component of the stator phase voltage in the k-th period in the two-phase stationary coordinate system, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively. Let α and β represent the first magnetic flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K1 represent the α-axis and β-axis components of the second flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively, and let K1 represent the first feedback matrix. 1α k 1β This represents the feedback coefficient of the first feedback matrix.

4. The asynchronous motor control method as described in claim 1, characterized in that, The step of obtaining the second magnetic flux linkage in the k-th period based on the stator phase current in the k-th period, the rotational speed in the (k-1)-th period, the first magnetic flux linkage in the (k-1)-th period, and the second magnetic flux linkage in the (k-1)-th period includes: The second flux linkage in the k-th period is obtained based on the stator phase current in the k-th period, the mutual inductance in the k-th period, the rotor time constant in the k-th period, the rotational speed in the (k-1)-th period, the first flux linkage in the (k-1)-th period, and the second flux linkage in the (k-1)-th period.

5. The asynchronous motor control method as described in claim 4, characterized in that, The formula for calculating the second magnetic flux linkage in the k-th period is: Where p represents the differentiation operator. Let α and β represent the components of the second magnetic flux in the k-th period in the two-phase stationary coordinate system, respectively. L represents the rotational speed in the (k-1)th cycle. m，k τ r，k Let i represent the mutual inductance in the k-th period and the rotor time constant in the k-th period, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively. Let α and β represent the first magnetic flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K1 and K2 represent the α-axis and β-axis components of the second flux linkage in the (k-1)th period in the two-phase stationary coordinate system, respectively. Let K2 represent the second feedback matrix. 2α k 2β This represents the feedback coefficient of the second feedback matrix.

6. The asynchronous motor control method as described in claim 1, characterized in that, The step of obtaining the rotational speed in the k-th period based on the error between the first magnetic flux linkage and the second magnetic flux linkage in the k-th period, and the stator phase current in the k-th period, includes: The error between the first magnetic flux linkage and the second magnetic flux linkage in the k-th period is cross-multiplied with the stator phase current in the k-th period to obtain the first input value; Integrate the first input value to obtain the rotational speed in the kth cycle; Alternatively, the error between the first magnetic flux linkage and the second magnetic flux linkage in the kth period can be multiplied by the stator phase current in the kth period to obtain the second input value. Integrate the second input value to obtain the rotational speed of the kth cycle.

7. The asynchronous motor control method as described in claim 6, characterized in that, The formula for calculating the first input value is: The formula for calculating the second input value is: in, The transpose of the error between the first flux linkage in period k and the second flux linkage in period k is given by i. s，k This represents the stator phase current in the k-th period. Let α and β represent the first magnetic flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. Let i represent the α-axis component and β-axis component of the second flux linkage in the k-th period in the two-phase stationary coordinate system, respectively. sα，k i sβ，k Let α and β represent the stator phase current in the k-th period in the two-phase stationary coordinate system, respectively.

8. The asynchronous motor control method as described in claim 1, characterized in that, The step of obtaining the third magnetic flux linkage of the k-th period based on the first magnetic flux linkage of the k-th period and the second magnetic flux linkage of the k-th period includes: The third magnetic flux of the k-th period is obtained by taking a weighted average of the first magnetic flux and the second magnetic flux of the k-th period. Alternatively, a high-pass filter can be applied to one of the first magnetic flux linkage and the second magnetic flux linkage in the k-th period, and a low-pass filter can be applied to the other to obtain the third magnetic flux linkage in the k-th period.

9. The asynchronous motor control method as described in claim 1, characterized in that, The step of obtaining the flux linkage angle of the k-th period based on the third flux linkage of the k-th period includes: The flux linkage angle of the k-th period is obtained by using a phase-locked loop based on the third flux linkage of the k-th period; Alternatively, the inverse tangent values ​​of the α-axis and β-axis components of the third flux linkage in the k-th period can be obtained to get the flux linkage angle in the k-th period.

10. An asynchronous motor control device, characterized in that, include: The first flux linkage estimation unit is used to obtain the first flux linkage of the k-th period based on the stator phase voltage and stator phase current of the k-th period, as well as the first flux linkage of the (k-1)-th period and the second flux linkage of the (k-1)-th period. The second flux linkage estimation unit is used to obtain the second flux linkage in the k-th period based on the stator phase current in the k-th period, the rotational speed in the (k-1)-th period, the first flux linkage in the (k-1)-th period, and the second flux linkage in the (k-1)-th period. The rotational speed estimation unit is used to obtain the rotational speed of the k-th cycle based on the error between the first magnetic flux linkage and the second magnetic flux linkage of the k-th cycle, and the stator phase current of the k-th cycle. The third flux linkage estimation unit is used to obtain the third flux linkage of the k-th period based on the first flux linkage of the k-th period and the second flux linkage of the k-th period. A flux linkage angle estimation unit is used to obtain the flux linkage angle of the k-th period based on the third flux linkage of the k-th period. A feedback control unit is used to perform feedback control on the asynchronous motor in the (k+1)th cycle based on the flux linkage angle and the rotational speed in the kth cycle. Where k is any positive integer.

11. An asynchronous motor controller, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the asynchronous motor control method as described in any one of claims 1 to 9.

12. A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the asynchronous motor control method as claimed in any one of claims 1 to 9.

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