Method, device and equipment for controlling a synchronous machine and a synchronous machine system

Abstract

The present disclosure relates to the technical field of synchronous machines, and in particular, to a control method and device of a synchronous machine, an equipment and a synchronous machine system. The electromagnetic time constant of the synchronous machine is less than a first threshold. The control method of the synchronous machine comprises: determining an actual rotating speed and a target rotating speed; determining a target control current based on the actual rotating speed, the target rotating speed and a rotating speed loop control model; wherein the rotating speed loop control model is a relationship between a rotating speed error and the target control current determined based on a Lyapunov function; determining a target control voltage corresponding to the target control current according to a current-voltage conversion model; wherein the current-voltage conversion model is a relationship between the target control current and the target control voltage determined by eliminating a direct-axis voltage in a state equation of the synchronous machine; and controlling the synchronous machine according to the target control voltage.

Description

Technical Field

[0001] This disclosure relates to the field of synchronous motor technology, and in particular to a control method, device, equipment and synchronous motor system for a synchronous motor. Background Technology

[0002] In related technologies, for the control of permanent magnet synchronous motors, after determining the target control current, a closed-loop control method can usually be adopted to determine the difference between the target control current and the actual current. Then, a Lyapunov function is constructed to determine the relationship between the actual current, the target control current and the target control voltage in a more complex way, and then the target control voltage is determined for control.

[0003] This approach is relatively complex in terms of process, and in some scenarios (such as scenarios with a high rate of change of current), it is difficult to accurately measure the actual current value. In such cases, model prediction of current or establishment of a current observer is generally used, which is costly and has poor control effect and stability. Summary of the Invention

[0004] To overcome the problems existing in the related technologies, this disclosure provides a control method, device, equipment and synchronous motor system for a synchronous motor, which can solve the above problems.

[0005] According to a first aspect of the present disclosure, a control method for a synchronous motor is provided, wherein the electromagnetic time constant of the synchronous motor is less than a first threshold. The method includes: determining an actual rotational speed and a target rotational speed; determining a target control current based on the actual rotational speed, the target rotational speed, and a speed loop control model; wherein the speed loop control model is a relationship between rotational speed error and target control current determined based on a Lyapunov function; determining a target control voltage corresponding to the target control current according to a current-voltage conversion model; wherein the current-voltage conversion model is a relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor's state equation; and controlling the synchronous motor according to the target control voltage.

[0006] According to a second aspect of the present disclosure, a control device for a synchronous motor is provided, wherein the electromagnetic time constant of the synchronous motor is less than a first threshold. The device includes: a parameter determination unit configured to determine an actual rotational speed and a target rotational speed; a current determination unit configured to determine a target control current based on the actual rotational speed, the target rotational speed, and a speed loop control model; wherein the speed loop control model is a relationship between rotational speed error and target control current determined based on a Lyapunov function; a voltage conversion unit configured to determine a target control voltage corresponding to the target control current according to a current-voltage conversion model; wherein the current-voltage conversion model is a relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation; and a motor control unit configured to control the synchronous motor according to the target control voltage.

[0007] According to a third aspect of the present disclosure, an electronic device is provided, comprising: a processor and a memory; the memory being used to store a computer program; and the processor being used to execute the synchronous motor control method as described in the first aspect by invoking the computer program.

[0008] According to a fourth aspect of the present disclosure, a synchronous motor system is provided, the system including a control module and a synchronous motor; wherein the control module executes the synchronous motor control method as described in the first aspect to control the synchronous motor.

[0009] According to a fifth aspect of the present disclosure, a computer program product is provided, including a computer program that, when executed by a processor, implements the method as described in the first aspect.

[0010] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects: The synchronous motor disclosed herein has an electromagnetic time constant less than a first threshold and a small inductance. This disclosure can determine the actual speed and the target speed, and then, based on the determined speed loop control model and current-voltage conversion model, determine the corresponding target control voltage, and control the synchronous motor based on the target control voltage.

[0011] The current-voltage conversion model in this disclosure is based on the state equations of a synchronous motor. Since the method described here is specifically for synchronous motors with small inductance, it differs from related technologies that eliminate the influence of direct-axis current in the synchronous motor state equations. This disclosure eliminates direct-axis voltage from the synchronous motor state equations, thereby determining the conversion relationship between quadrature-axis current and quadrature-axis voltage. Therefore, it allows for the determination of the target control voltage based on the target control current without needing to determine the actual current. On the one hand, the method described here is simpler, faster, and less costly. On the other hand, in scenarios where the actual current is difficult to determine, the method described here exhibits better control performance and stronger stability.

[0012] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this disclosure, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0014] Figure 1 This is a schematic flowchart illustrating a control method for a synchronous motor according to an exemplary embodiment of the present disclosure.

[0015] Figure 2 This disclosure is a schematic block diagram illustrating a control method for a synchronous motor according to an exemplary embodiment.

[0016] Figure 3 This disclosure is a schematic block diagram illustrating a control method for a synchronous motor according to an exemplary embodiment.

[0017] Figure 4 This disclosure is a block diagram illustrating a control device for a synchronous motor according to an exemplary embodiment.

[0018] Figure 5 This is a schematic diagram of the structure of a computer device according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0020] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0022] The control of permanent magnet synchronous motors typically employs model predictive current control, current observer control, and open-loop current control.

[0023] The accuracy of model predictive current control is highly dependent on an accurate motor model. It is prone to steady-state errors when parameters are mismatched, resulting in a significant decrease in robustness and susceptibility to limitations in chip computing power.

[0024] Current observer control is complex and requires careful design and tuning of various parameters of the current observer. Furthermore, it is difficult to simultaneously achieve fast convergence and stable performance in high current change rate applications.

[0025] In related technologies, current open-loop control mainly relies on traditional proportional-integral control, which results in high system sensitivity, low robustness, and difficulty in parameter tuning. The uncontrollable current also leads to poor safety.

[0026] The three related technologies mentioned above still require determining the relationship between the target control current, the actual current, and the target control voltage. The difference between the three methods lies in whether the actual current is the predicted current, the observed current, or even simply ignored. None of these methods can achieve the requirement of stable rotational speed with minimal fluctuations under steady-state conditions. In scenarios with high current change rates, both accuracy and stability are low.

[0027] To address the aforementioned technical problems, this disclosure proposes a control method for synchronous motors.

[0028] Figure 1This is a schematic flowchart illustrating a control method for a synchronous motor according to an embodiment of the present disclosure. The control method for the synchronous motor can be executed by a terminal. The control method for the synchronous motor proposed in this disclosure can be used to control the input module of the synchronous motor. For example, the input module can be an inverter. This disclosure can control the inverter, changing the switching state of the inverter so that the inverter outputs a current that meets the requirements when controlled. This current is used for the operation of the synchronous motor, thereby realizing the control of the synchronous motor.

[0029] like Figure 1 As shown, the control methods for synchronous motors include: In step S101, the actual rotational speed and the target rotational speed are determined; In step S102, the target control current is determined based on the actual rotational speed, the target rotational speed, and the rotational speed loop control model; wherein, the rotational speed loop control model is the relationship between the rotational speed error and the target control current determined based on the Lyapunov function; In step S103, the target control voltage corresponding to the target control current is determined according to the current-voltage conversion model; wherein, the current-voltage conversion model is the relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation; In step S104, the synchronous motor is controlled according to the target control voltage.

[0030] In some embodiments, the electromagnetic time constant of the synchronous motor is less than a first threshold.

[0031] The electromagnetic time constant is the ratio of inductance to resistance. When the electromagnetic time constant is small, the synchronous motor can be considered a low-inductance synchronous motor. In this case, the influence of the synchronous motor's inductance on the direct-axis voltage and current is much smaller than the influence of the resistance.

[0032] In some embodiments, the actual rotational speed and the target rotational speed are determined.

[0033] The actual speed of a synchronous motor can be determined using sensors. For example, the rotation angle of the synchronous motor can be determined by an encoder, and then the actual speed can be determined by taking the derivative over time.

[0034] It can receive user commands and determine the target speed based on those commands. The target speed is the speed indicated by the user, which is also the control objective. After controlling the synchronous motor using the control method disclosed herein, the output speed of the synchronous motor can be made to be the target speed.

[0035] In some embodiments, the target control current is determined based on the actual rotational speed, the target rotational speed, and the rotational speed loop control model; wherein the rotational speed loop control model is the relationship between the rotational speed error and the target control current determined based on the Lyapunov function.

[0036] The speed loop control model can determine the target control current based on the target speed and the actual speed. A Lyapunov function including a speed error term can be constructed, and then combined with the synchronous motor state equations to derive the speed loop control model. This will not be elaborated upon here, but will be explained in detail with examples later.

[0037] In some embodiments, the target control current corresponds to the target rotational speed.

[0038] The input terminal of the synchronous motor is connected to the inverter module, but the inverter cannot be directly controlled by the target control current. Therefore, it is necessary to determine the target control voltage corresponding to the target control current.

[0039] By controlling the inverter module based on the target control voltage, the inverter module can output the required output, which is then sent to the synchronous motor to make the synchronous motor reach the target speed.

[0040] In some embodiments, the target control current is a quadrature-axis current and the target control voltage is a quadrature-axis voltage.

[0041] Control is achieved using quadrature axis current and quadrature axis voltage.

[0042] In some embodiments, the target control voltage corresponding to the target control current is determined according to a current-voltage conversion model; wherein, the current-voltage conversion model is the relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation.

[0043] The state equations of a synchronous motor typically include the direct-axis current state equation, the quadrature-axis current state equation, and the speed state equation.

[0044] Since the control method disclosed herein is for synchronous motors with an electromagnetic time constant less than a first threshold, and the influence of inductance on the direct-axis current and voltage of such synchronous motors is much smaller than the influence of resistance, the influence of direct-axis voltage can be eliminated in the synchronous motor state equations. For example, the direct-axis voltage can be set to 0.

[0045] After eliminating the direct-axis voltage, the derivation of the state equation reveals a linear relationship between the target control current and the target control voltage, which does not include the actual current. This indicates that the method of this disclosure does not require measuring, predicting, or observing the actual current to determine the target control voltage; the target control voltage can be determined directly based on the target control current determined by the target rotational speed.

[0046] In some embodiments, based on the speed loop control model and the current-voltage conversion model, the speed loop control law can be determined, which includes the relationship between the actual speed, the target speed and the target control voltage.

[0047] The speed loop control model and the current-voltage conversion model can be integrated into a single control law. This control law can directly determine the target control voltage based on the actual speed determined by the sensor and the target speed input by the user, simplifying the control process and making it efficient and stable.

[0048] In some embodiments, the synchronous motor is controlled according to the target control voltage.

[0049] The target control current is determined based on the target speed, and the target control voltage is determined based on the target control current. Therefore, control based on the target control voltage can enable the synchronous motor to reach the target speed.

[0050] For example, the target control voltage can be transformed into a corresponding voltage vector, and then the switching state of the inverter module can be controlled based on the voltage vector. Since the switching state of the inverter module is controlled, the AC power output by the inverter module will also change accordingly. This AC power is used to supply power to the synchronous motor, thereby controlling the speed of the synchronous motor to reach the target speed.

[0051] The synchronous motor control method proposed in this disclosure, specifically for small inductance synchronous motors, eliminates the direct-axis voltage in the synchronous motor state equation and further derives and determines the relationship between the target control current and the target control voltage. This allows the target control current to be determined quickly and accurately based on the target control current, eliminating the need for a closed-loop control scheme based on the actual current to determine the target control voltage. This simplifies the control process, reduces control delay, and ensures stable speed with minimal fluctuations in steady state, resulting in precise control without overshoot.

[0052] In some embodiments, the state equations of a synchronous motor may include a direct-axis current state equation, a quadrature-axis current state equation, and a speed state equation.

[0053] For small inductance synchronous motors (such as micro permanent magnet synchronous motors), the rotor diameter is very small and the rotor volume is also very small. Since the wind resistance is proportional to the rotor volume, the wind resistance is also very small and can be ignored.

[0054] The state equation of a synchronous motor can be expressed as: (1) These correspond to the state equations for direct-axis current, quadrature-axis current, and rotational speed, respectively.

[0055] in, , These are the direct-axis and quadrature-axis currents of the motor, respectively. , These represent the direct-axis and quadrature-axis voltages of the motor, respectively; L is the stator inductance. For stator resistance, The mechanical angular velocity of the motor. denoted as ω0, where ω is the electric angular velocity of the motor, p is the number of pole pairs of the motor, and J is the moment of inertia of the motor rotor. It is a permanent magnet flux chain. This represents the load torque.

[0056] The state equations of a synchronous motor describe the relationships between direct-axis current, quadrature-axis current, speed, and other parameters.

[0057] In some embodiments, the current-voltage conversion model is determined by the following method: determining that the direct-axis voltage in the synchronous motor state equation is 0, and determining that the voltage drop of the direct-axis inductor of the synchronous motor is 0; deriving the direct-axis current state equation in the synchronous motor state equation based on the direct-axis voltage being 0 and the voltage drop of the direct-axis inductor being 0, to determine the relationship between the direct-axis current and the quadrature-axis current; substituting the relationship between the direct-axis current and the quadrature-axis current and the voltage drop of the quadrature-axis inductor being 0 into the quadrature-axis current state equation in the synchronous motor state equation, to determine the relationship between the quadrature-axis current and the quadrature-axis voltage, wherein the target control current is the quadrature-axis current and the target control voltage is the quadrature-axis voltage.

[0058] For small inductance synchronous motors, as mentioned above, the direct-axis voltage of the inductor is extremely small; therefore, in this embodiment, the direct-axis voltage is determined to be 0 (…). Based on this, the state equations of the synchronous motor are derived and simplified.

[0059] Substituting the direct-axis voltage of 0 into the state equation for the d-axis current, we get: (2) By determining that the voltage drop across the small inductor is 0, equation (2) can be further simplified, thus obtaining the result. Approximate linear relationship between direct-axis and quadrature-axis currents under control: (3) Substituting formula (3) into the state equation of the quadrature axis (q-axis) current in the synchronous motor state equation, and ignoring the voltage drop of the small inductor and the direct axis voltage of the small inductor, we can obtain the current-voltage conversion model. The current-voltage conversion model is used to represent the relationship between the quadrature axis current and the quadrature axis voltage, that is, the relationship between the control current and the control voltage.

[0060] The current-voltage conversion model is as follows: (4) Simplifying formula (4), we can obtain an approximate relationship (5) between q-axis current and q-axis voltage. This relationship is also the current-voltage conversion model: (5) in, It is a quantity that varies only with rotational speed. In some embodiments, under low-speed operating conditions, it can be approximated in engineering as... We can ignore the impact of this factor; however, under high-speed operating conditions, It is relatively large and cannot be ignored.

[0061] As can be seen from the current-voltage conversion model, apart from the q-axis current and q-axis voltage, the other parameters in the model do not involve the actual current. Therefore, it avoids the problem of error and control inaccuracy caused by the difficulty in accurately determining the actual current in scenarios with large current change rates. This makes the method disclosed in this paper faster and more precise in control.

[0062] In some embodiments, the speed loop control model can be determined based on Lyapunov functions.

[0063] By constructing a Lyapunov function that includes a speed error term, and then deriving the Lyapunov function in conjunction with the motor synchronization state equation, the speed loop control model can be determined.

[0064] Furthermore, since some parameters of the synchronous motor may change during operation, the constructed Lyapunov function can also include an identification parameter term to adaptively identify some parameters of the synchronous motor, thereby improving the robustness of the system.

[0065] In some embodiments, the identification parameters include at least one of the following: identification resistance, identification load torque.

[0066] For small inductance synchronous motors, due to their high resistance, low efficiency, and unfavorable heat dissipation structure, temperature rise will affect the stator resistance in the model. This can have an impact, leading to errors. Therefore, adaptive parameter identification of the stator resistance can be performed to correct the effects of resistance observation errors caused by temperature rise.

[0067] For small inductance synchronous motors, the load torque is very small (typically in the range of...). The torque is on the order of Nm and is difficult to measure directly with a torque sensor. Therefore, it can also adaptively identify the load torque to obtain a more accurate load torque.

[0068] Regarding inductance and flux linkage, if the synchronous motor has a large inductance, magnetic saturation may occur, thus affecting the stator inductance L and flux linkage. Errors can also be reduced through adaptive parameter identification. It should be noted that in the scenario of a small-inductance synchronous motor without a stator core, the inductance is small, there is no magnetic saturation effect, and the stator inductance L and magnetic flux linkage are related. Since the changes are minor, adaptive identification is not required. Technicians can make flexible choices based on actual application scenarios, and this disclosure does not impose any restrictions on this.

[0069] In some embodiments, the Lyapunov function includes a speed error term and an identification parameter term; the method further includes: deriving the identification parameter model and the corresponding speed loop control model by combining the speed state equation in the synchronous motor state equation with the Lyapunov function, wherein the speed loop control model includes identification parameters, and the identification parameters are determined by the identification parameter model; determining the target control current includes: determining the identification parameters and determining the target control current corresponding to the identification parameters.

[0070] Define the speed error as the actual speed With target speed The difference is expressed by the formula: A speed error term is constructed based on this speed error.

[0071] We can define the observed and error values ​​of the identification parameters, and then construct the identification parameter terms in the Lyapunov function based on the observed and error values ​​of the identification parameters.

[0072] Based on the speed error term and the identification parameter term, a Lyapunov function is constructed. Then, based on the principle of the Lyapunov function and combined with the speed state equation of the synchronous motor, the identification parameters and quadrature axis current (or quadrature axis voltage) are solved, thereby determining the expression of the identification parameters and the corresponding expression of the target control current (or target control voltage).

[0073] For example, taking the identification parameters including the identification resistance and the identification load torque as an example, the observed value of the stator resistance is... The observation error of the stator resistance is The observed load torque value is The load torque observation error is The Lyapunov function V1, which includes the speed error term and the identification parameter term, is constructed as follows: (6) in, and These are the adaptive increment rates of the stator resistance and load torque observations, respectively. It should be noted that, for ease of description, this example considers both the identification resistance term and the identification load torque term. This should not limit the scope of protection of this disclosure. In fact, only one of these terms can be considered, along with the Lyapunov function constructed with the speed error term. Alternatively, other identification parameters (such as identification inductance, identification flux linkage, etc.) besides the identification resistance and identification load torque can be considered.

[0074] Differentiating the constructed Lyapunov function (Equation (6)) and substituting the speed state equation (the third term in Equation (1)) in the synchronous motor state equation, we obtain Equation (7):

[0075] The intermediate derivation and simplification processes are omitted. For example, after differentiating the speed error, it is substituted into the speed state equation; another example is that, to ensure the derivative of the Lyapunov function is always less than 0, a positive derivative is added after differentiating the speed error. Item and negative Item, and will be negative The proposal is to construct a system that is always less than 0. .

[0076] in, For positive integer terms, it can be 1 or other positive integers.

[0077] Based on this formula (7), combined with the Lyapunov function principle, the expression for the identification parameter can be determined, and the expression for the target control current corresponding to the identification parameter can be determined.

[0078] Furthermore, in the scenario of a small inductance synchronous motor, based on the current-voltage conversion model proposed in the above embodiments of this disclosure, there is a conversion relationship between q-axis current and q-axis voltage. Therefore, the current-voltage conversion model (Equation (5)) can be substituted into the derivative of the Lyapunov function (Equation (7)) to obtain Equation (8):

[0079] By further solving formula (8), the voltage control law and the observation approach law of each identification parameter can be determined.

[0080] For example, when it is necessary to identify the parameters of the stator resistance, the identification load torque term in equation (8) can be ignored, and the load torque can be assumed to remain unchanged. The derivative of the Lyapunov function is determined to be always less than 0, and the expressions of the voltage control law and the resistance observation approach law can be obtained: (9) The solution process has been partially omitted. For example, the voltage control law can be obtained based on the fact that the speed error term is always less than 0, and the resistance observation approach law can be obtained based on identifying the terms related to the load torque and the target speed in the resistance term and the speed error term. The solution is always less than 0.

[0081] For example, when it is necessary to identify the load torque parameters, the identification resistance term in equation (8) can be ignored, the stator resistance can be assumed to remain unchanged, and based on the fact that the derivative of the Lyapunov function is always less than 0, the expressions for the voltage control law and the load torque observation approach law can be obtained: (10) The solution process has been partially omitted. For example, identifying the load torque is based on identifying the load torque term and the speed error term, specifically the terms related to the load torque. The solution is always less than 0.

[0082] Under the conditions that both the formula (9) and the formula (10) are met, there exists The derivative of the Lyapunov function is always less than 0, indicating that the system is stable.

[0083] In some embodiments, the construction of the speed loop control law includes a voltage control law and a resistance observation approach law.

[0084] Because the synchronous motor generates a large temperature rise during the speed loop control process, the stator resistance has a large error, requiring adaptive identification of the stator resistance; however, the load torque does not change during the speed loop control process, so parameter identification of the load torque is not required.

[0085] In some embodiments, controlling the synchronous motor based on the target control voltage includes: using a direct-axis voltage of 0 in the vector control section, determining a target voltage vector based on the target control voltage, and controlling the inverter module based on the target voltage vector.

[0086] After determining the target control voltage based on the method of the above embodiments of this disclosure, the direct axis voltage can be set to 0, the target voltage vector can be determined based on the target control voltage, and then subsequent control can be performed.

[0087] Figure 2 This is a schematic block diagram illustrating a control method for a synchronous motor according to an embodiment of the present disclosure.

[0088] like Figure 2 As shown, a permanent magnet synchronous motor can determine angle information based on an encoder (position sensor), and the actual rotational speed can be determined by taking the time derivative of the angle information. ; Receive target rotation speed input by the user This allows us to determine the speed error. .

[0089] Speed ​​error Combined with load torque An adaptive parameter identification model (e.g., the expression for the identification resistor in formula (9)) can be input to determine the identification parameters. In the case of a small inductance synchronous motor, the load torque... The value can be 0, and the identification parameters can also include only the identification resistor. .

[0090] By determining the identification parameters, speed error, and target speed input control model, the target control current can be determined. Then, the target control voltage is determined based on the current-voltage conversion model (Formula (5)). It should be noted that this step can also directly obtain the target control voltage by combining the identification parameters, speed error, and target speed input voltage control law (formula (9)). .

[0091] For target control voltage Using a direct-axis voltage of 0, the target voltage vector is determined through inverse Park transformation. and The target voltage vector is input into SVPWM (Space Vector Pulse Width Modulation), and further control (details omitted here) is used to control the speed of the permanent magnet synchronous motor to achieve the target speed.

[0092] Combination Figure 2 As can be seen from the control law given by formula (9), in the scheme disclosed herein, efficient and accurate control of the output speed of the synchronous motor can be achieved based on the actual speed and the target speed. During the control process, it is not necessary to measure the actual current, thus avoiding errors and time delays caused by the difficulty in accurately determining the actual current. Furthermore, the parameters used in this scheme can be adaptively identified, making the system more robust and avoiding control errors caused by system disturbances.

[0093] In addition to the above-mentioned methods for controlling the speed of a synchronous motor, this disclosure also provides examples of methods for controlling the position of a synchronous motor.

[0094] In some embodiments, the method further includes: determining an actual position and a target position, and determining a position error; determining a target control current based on the actual position, the target position, and a position loop control model; wherein the position loop control model is a relationship between the position error and the target control current determined based on a Lyapunov function.

[0095] Position loop control can be built on top of the speed loop. The current-voltage conversion model is the same, but the constructed Lyapunov functions are different.

[0096] A position loop control model is determined based on Lyapunov functions. This model includes the relationship between position error and target control current. Therefore, based on the actual position and the target position, the target control current (target control voltage) can be determined using the position loop control model.

[0097] In some embodiments, the position loop control model is determined by the following method: constructing a first-order Lyapunov function containing a position error term; determining a second-order error based on the time derivative of the actual rotational speed and the target position; constructing a second-order Lyapunov function containing a second-order error term and the first-order Lyapunov function; determining the relationship between the position error and the second-order error based on the second-order Lyapunov function, and combining the rotational speed state equation to determine the position loop control model.

[0098] Since synchronous motors can reach the target position by controlling the speed, and the state equation of a synchronous motor does not include the position state equation but only the speed state equation, the derivative of the position error is related to the speed. Therefore, the determination of the position loop control model requires the construction of two-level Lyapunov functions.

[0099] Based on the constructed Lyapunov function and combined with the state equation of the synchronous motor, the position loop control model can be determined.

[0100] In some embodiments, the first-order Lyapunov function further includes the identification parameter term, and the method further includes: determining the identification parameter model and the position loop control model corresponding to the position loop, wherein the identification parameter model corresponding to the position loop is used to determine the identification parameter based on the actual position and the target position; determining the target control current includes: determining the identification parameter based on the actual position and the target position, and determining the target control current corresponding to the identification parameter.

[0101] Similar to the speed loop, identification parameter terms can also be added during the construction of the Lyapunov function of the position loop. By solving for the identification parameter terms, control errors caused by parameter disturbances in the system can be eliminated, thereby improving the accuracy and robustness of control.

[0102] It should be noted that this disclosure does not limit the selection of identification parameters.

[0103] The following section will continue to use the identification parameters, including the identification resistance and the identification load torque, as examples to provide a detailed introduction to the first-order Lyapunov function, the second-order Lyapunov function, and the position loop control model constructed for the position loop.

[0104] Position error can be defined , To determine the target position based on the given position signal, a first-order Lyapunov function is constructed, including a position error term and an identification parameter term: (11) Differentiating formula (11) determines the derivative of the first-order Lyapunov function: (12) In some embodiments, virtual control variables may be introduced. Based on virtual control quantity Determine the control error, and construct the second-level Lyapunov function based on the control error term and the first-level Lyapunov function.

[0105] Virtual control quantity This is an intermediate value and does not affect the final control result. Speed ​​and virtual control values ​​can be defined. control error Virtual control quantity , It is a positive number.

[0106] Constructing a second-order Lyapunov function based on the control error term and the first-order Lyapunov function: (13) Differentiating the second-order Lyapunov function yields: (14) Based on the derivative of the second-order Lyapunov function, when satisfying , When it is a positive integer, there exists The system is stable.

[0107] It should be noted that, and This is used to coordinate the weights between position and speed errors, preventing one from being too large and the other too small, which would result in the smaller-weighted error having too little impact. Therefore, it uses... and The weights for coordinating position and speed errors are determined. A reasonable approach is presented here. and The method for determining the value of can be as large as possible while ensuring the steady-state performance of the system. The value of , and make and The following relationship must be satisfied: and The ratio is the square of the ratio of the motor's rated speed to the target position. Based on the control law expression... By combining the first-order Lyapunov function and the second-order Lyapunov function, the position loop control model (position loop control law) can be obtained.

[0108] When it is necessary to identify the parameters of the stator resistance, the voltage control law and the resistance observation approach law of the position loop are:

[0109] (15) When it is necessary to identify the parameters of the load torque, the voltage control law of the position loop and the load torque observation approach law are as follows:

[0111] (16) In some embodiments, the position loop control model includes a voltage control law and a load torque observation approach law (Equation (16)).

[0112] During the position loop control process, since the time required for the synchronous motor to reach the target position is short, usually within a few tenths of a millisecond, the heat generation is small and the temperature rise is small, resulting in a very small change in the stator resistance of the synchronous motor. Therefore, the identification resistor can be disregarded.

[0113] In the application of the position loop, the added load torque is relatively large, which makes the possible error of the load torque have a significant impact on the control accuracy. Therefore, it is necessary to adaptively identify the load torque to improve control accuracy and control robustness.

[0114] Figure 3 This is a schematic block diagram illustrating a control method for a synchronous motor according to an embodiment of the present disclosure.

[0115] like Figure 3 As shown, the position information (actual position) of the permanent magnet synchronous motor can be determined through the encoder. ), the actual location On the one hand, with the given target location Determine position error On the other hand, regarding the actual location Perform time differentiation to determine the actual rotational speed. .

[0116] Position error Actual speed Target location and load torque By inputting the adaptive parameter identification model (Equations (15) and (16)), the identification parameters can be determined. In one embodiment, the position loop control may identify only the load torque and determine the identified load torque. .

[0117] target location Position error And identify load torque By inputting the position loop control model, the target control current can be determined, and then the target control voltage can be determined based on the current-voltage conversion model. Of course, it can also be based on the voltage control law of the position loop (Equation (16)) and the target position. Position error And identify load torque Directly determine the target control voltage .

[0118] Determining the target control voltage For subsequent control procedures, please refer to [link / reference]. Figure 2 The relevant control process of the speed loop will not be elaborated here.

[0119] Combination Figure 3 As can be seen from the control law given by formula (16), in the scheme disclosed herein, efficient and accurate control of the output position of the synchronous motor can be achieved based on the actual position and the target position, which has good technical effect.

[0120] Corresponding to the embodiments of the synchronous motor control method of this disclosure, this disclosure also provides embodiments of the corresponding synchronous motor control device.

[0121] Please see Figure 4 , Figure 4 This is a block diagram of a control device for a synchronous motor according to one embodiment of this disclosure. Figure 4 As shown, the electromagnetic time constant of the synchronous motor is less than a first threshold, and the control device for the synchronous motor includes: The parameter determination unit 410 is configured to determine the actual rotational speed and the target rotational speed; The current determination unit 420 is configured to determine the target control current based on the actual rotational speed, the target rotational speed, and the rotational speed loop control model; wherein the rotational speed loop control model is a relationship between the rotational speed error and the target control current determined based on the Lyapunov function. The voltage conversion unit 430 is configured to determine the target control voltage corresponding to the target control current according to the current-voltage conversion model; wherein, the current-voltage conversion model is the relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation; The motor control unit 440 is configured to control the synchronous motor according to the target control voltage.

[0122] In some embodiments, the current-voltage conversion model is determined by the following method: determining that the direct-axis voltage in the synchronous motor state equation is 0, and determining that the voltage drop of the direct-axis inductor of the synchronous motor is 0; deriving the direct-axis current state equation in the synchronous motor state equation based on the direct-axis voltage being 0 and the voltage drop of the direct-axis inductor being 0, to determine the relationship between the direct-axis current and the quadrature-axis current; substituting the relationship between the direct-axis current and the quadrature-axis current and the voltage drop of the quadrature-axis inductor being 0 into the quadrature-axis current state equation in the synchronous motor state equation, to determine the relationship between the quadrature-axis current and the quadrature-axis voltage, wherein the target control current is the quadrature-axis current and the target control voltage is the quadrature-axis voltage.

[0123] In some embodiments, the Lyapunov function includes a speed error term and an identification parameter term; the device is further configured to: derive an identification parameter model and a corresponding speed loop control model by combining the speed state equation in the synchronous motor state equation with the Lyapunov function, wherein the speed loop control model includes identification parameters, and the identification parameters are determined by the identification parameter model; determining the target control current includes: determining the identification parameters and determining the target control current corresponding to the identification parameters.

[0124] In some embodiments, the identification parameters include at least one of the following: identification resistance, identification load torque.

[0125] In some embodiments, the device is further configured to: determine an actual position and a target position, and determine a position error; determine a target control current based on the actual position, the target position, and a position loop control model; wherein the position loop control model is a relationship between the position error and the target control current determined based on a Lyapunov function.

[0126] In some embodiments, the position loop control model is determined by the following method: constructing a first-order Lyapunov function containing a position error term; determining a second-order error based on the time derivative of the actual rotational speed and the target position; constructing a second-order Lyapunov function containing a second-order error term and the first-order Lyapunov function; determining the relationship between the position error and the second-order error based on the second-order Lyapunov function, and combining the rotational speed state equation to determine the position loop control model.

[0127] In some embodiments, the first-order Lyapunov function further includes the identification parameter term, and the device is further configured to: determine the identification parameter model and the position loop control model corresponding to the position loop, wherein the identification parameter model corresponding to the position loop is used to determine the identification parameter based on the actual position and the target position; the determination of the target control current includes: determining the identification parameter based on the actual position and the target position, and determining the target control current corresponding to the identification parameter.

[0128] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0129] Embodiments of this disclosure also provide an electronic device, including: a processor and a memory; the memory for storing a computer program; and the processor for executing a synchronous motor control method as described in any of the above embodiments by invoking the computer program.

[0130] Embodiments of this disclosure also provide a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the synchronous motor control method as described in any of the above embodiments.

[0131] Embodiments of this disclosure also provide a computer program product, including a computer program that, when executed by a processor, implements the methods described in any of the foregoing embodiments.

[0132] Embodiments of this disclosure also propose a synchronous motor system, the system including a control module and a synchronous motor; wherein the control module executes the synchronous motor control method as described in any of the above embodiments to control the synchronous motor.

[0133] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present invention, such as... Figure 5 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system).

[0134] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0135] The memory 20 stores instructions executable by at least one processor 10 to cause at least one processor 10 to perform the method shown in the above embodiments.

[0136] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device as shown by a landing page for an app. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, which can be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0137] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0138] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0139] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0140] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

[0141] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0142] The methods and apparatus provided in the embodiments of this disclosure have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this disclosure. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this disclosure. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this disclosure. Therefore, the content of this specification should not be construed as a limitation of this disclosure.

Claims

1. A control method for a synchronous motor, characterized in that, The electromagnetic time constant of the synchronous motor is less than a first threshold, and the method includes: Given a target speed determined by instructions, determine the actual speed and the target speed. The target control current is determined based on the actual rotational speed, the target rotational speed, and the rotational speed loop control model; wherein, the rotational speed loop control model is the relationship between the rotational speed error and the target control current determined based on the Lyapunov function; The target control voltage corresponding to the target control current is determined according to the current-voltage conversion model; wherein, the current-voltage conversion model is the relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation; The synchronous motor is controlled according to the target control voltage.

2. The method according to claim 1, characterized in that, The current-voltage conversion model was determined using the following method: The direct-axis voltage in the synchronous motor state equation is determined to be 0, and the voltage drop across the direct-axis inductance of the synchronous motor is determined to be 0. Based on the fact that the direct-axis voltage is 0 and the voltage drop of the direct-axis inductor is 0, the direct-axis current state equation in the synchronous motor state equation is derived to determine the relationship between the direct-axis current and the quadrature-axis current. Substituting the relationship between the direct-axis current and the quadrature-axis current, and the voltage drop of the quadrature-axis inductor to 0, into the quadrature-axis current state equation in the synchronous motor state equation, the relationship between the quadrature-axis current and the quadrature-axis voltage is determined. The target control current is the quadrature-axis current, and the target control voltage is the quadrature-axis voltage.

3. The method according to claim 1, characterized in that, The Lyapunov function includes a rotational speed error term and an identification parameter term; The method further includes: By combining the speed state equation in the synchronous motor state equation with the Lyapunov function, the identification parameter model and the corresponding speed loop control model are determined. The speed loop control model contains identification parameters, which are determined by the identification parameter model. The determination of the target control current includes: Determine the identification parameters and the target control current corresponding to the identification parameters.

4. The method according to claim 3, characterized in that, The identification parameters include at least one of the following: identification resistance, identification load torque.

5. The method according to claim 1, characterized in that, The method further includes: Given a position signal, determine the target position, the actual position and the target position, and determine the position error. The target control current is determined based on the actual position, the target position, and the position loop control model; wherein, the position loop control model is the relationship between the position error and the target control current determined based on the Lyapunov function.

6. The method according to claim 5, characterized in that, The position loop control model was determined using the following method: Construct a first-order Lyapunov function that includes a position error term; The second-level error is determined based on the time derivative of the actual rotational speed and the target position; Construct a second-order Lyapunov function that includes a second-order error term and the first-order Lyapunov function; The relationship between the position error and the second-order error is determined based on the second-order Lyapunov function, and the position loop control model is determined in combination with the speed state equation.

7. The method according to claim 6, characterized in that, The first-order Lyapunov function also includes an identification parameter term, and the method further includes: Determine the identification parameter model and the position loop control model corresponding to the position loop, wherein the identification parameter model corresponding to the position loop is used to determine the identification parameters based on the actual position and the target position; The determination of the target control current includes: The identification parameters are determined based on the actual position and the target position, and the target control current corresponding to the identification parameters is determined.

8. A control device for a synchronous motor, characterized in that, The electromagnetic time constant of the synchronous motor is less than a first threshold, and the device includes: The parameter determination unit is configured to determine the actual speed and the target speed when the target speed is determined according to the instruction; The current determination unit is configured to determine the target control current based on the actual rotational speed, the target rotational speed, and the rotational speed loop control model; wherein the rotational speed loop control model is a relationship between the rotational speed error and the target control current determined based on the Lyapunov function. A voltage conversion unit is configured to determine the target control voltage corresponding to the target control current based on a current-voltage conversion model; wherein the current-voltage conversion model is the relationship between the target control current and the target control voltage derived by eliminating the direct-axis voltage in the synchronous motor state equation; The motor control unit is configured to control the synchronous motor according to the target control voltage.

9. An electronic device, characterized in that, include: Processor, memory; The memory is used to store computer programs; The processor is configured to execute the control method for the synchronous motor as described in any one of claims 1-7 by invoking the computer program.

10. A synchronous motor system, characterized in that, The system includes a control module and a synchronous motor; wherein... The control module executes the synchronous motor control method as described in any one of claims 1-7 to control the synchronous motor.

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