Motor output power limiting method and device

Abstract

The invention discloses a motor output power limiting method and device, and the method comprises the steps: obtaining an initial torque current value according to a given weight value, and enabling the initial torque current value to serve as a calibrated actual given torque current value after the initial torque current value is calibrated by an initial power calibration coefficient; obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotating speed value of the motor; obtaining a power error according to the maximum power set value and the current power value of the motor; obtaining a given torque current value according to the power error, the initial torque current value and a power controller parameter; and driving the motor according to the given torque current value, taking the given torque current value as a calibrated actual given torque current value, returning to the step of acquiring the current actual rotating speed value of the motor, and acquiring the current power value of the motor according to the calibrated actual given torque current value and the actual rotating speed value of the motor. According to the motor output power limiting method, the final torque given value of the motor is obtained through real-time dynamic calculation, and equipment is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular, to a method and device for limiting the output power of a motor. Background Art

[0002] In the prior art, the operating state of weight training equipment is basically determined by the self-weight of the equipment, inertia, system friction, and the force applied by the user. The weight training equipment in the prior art cannot intelligently adjust the weight to protect the functions of the user and the equipment. Among the weight training equipment in the prior art, an intelligent device that realizes weight adjustment through motor output is prone to the problem of motor overload. Summary of the Invention

[0003] The present invention provides a method and device for limiting the output power of a motor to solve the problem that the motor output in fitness equipment is prone to motor overload.

[0004] According to an aspect of the present invention, a method for limiting the output power of a motor is provided. The method includes: obtaining a given weight value, obtaining an initial torque current value according to the given weight value, and using the initial torque current value as a calibrated actual given torque current value after being calibrated by an initial power calibration coefficient, where the initial power calibration coefficient is 1;

[0005] Obtaining the current actual rotational speed value of the motor, and obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor;

[0006] Obtaining a maximum power setting value, and obtaining a power error according to the maximum power setting value and the current power value of the motor;

[0007] Obtaining a given torque current value according to the power error, the initial torque current value, and power controller parameters;

[0008] Driving the motor according to the given torque current value, using the given torque current value as the calibrated actual given torque current value, and returning to execute the step of obtaining the current actual rotational speed value of the motor, and obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0009] Optionally, the obtaining the initial torque current value according to the given weight value includes:

[0010] Obtaining the initial torque current value according to the ratio of the product of the given weight value and the winding radius of the motor to the motor torque coefficient.

[0011] Optionally, the obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor includes:

[0012] Obtain the current power value of the motor based on the product of the calibrated actual given torque current value, the motor torque coefficient, the motor speed, and the conversion coefficient; wherein the conversion coefficient is 0.1047.

[0013] Optionally, obtaining the power error according to the maximum power setting value and the current power value of the motor includes:

[0014] Obtain the power error according to the difference between the maximum power setting value and the current power value of the motor.

[0015] Optionally, obtaining the given torque current value according to the power error, the initial torque current value, and the power controller parameters includes:

[0016] Obtain the given torque current value according to the first expression group among the power error, the calibrated actual given torque current value, the power controller parameters, and the fixed torque current value;

[0017] The first expression group includes:

[0018]

[0019] Wherein, K p is the controller proportional parameter, K i is the controller integral parameter, k is the power calibration coefficient, i q0 is the initial torque current value, I q is the given torque current value.

[0020] Optionally, driving the motor according to the given torque current value includes:

[0021] Perform PI controller operation on the given torque current value and the actual torque current value of the motor to obtain the given torque voltage value, and perform PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain the given excitation voltage value;

[0022] Perform inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and the given β-axis voltage;

[0023] Perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switching signals of the inverter bridge; drive the motor according to the switching signals of the inverter bridge.

[0024] Optionally, before performing PI controller operation on the given torque current value and the actual torque current value of the motor to obtain the given torque voltage value, and performing PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain the given excitation voltage value, further includes:

[0025] Obtain the values of the three-phase currents of the motor; perform Clarke transformation on the three-phase currents of the motor to obtain the α-axis current and β-axis current of the motor;

[0026] Obtain the actual rotational speed value of the motor, and perform PARK transformation on the actual rotational speed value of the motor, the α-axis current, and the β-axis current to obtain the actual torque current value and the actual excitation current value of the motor.

[0027] According to another aspect of the present invention, there is provided a motor output power limiting device, including: a weight torque conversion module, a power calculation module, an error calculation module, a given torque current value calculation module, a motor drive module, and a cycle limiting module;

[0028] The weight torque conversion module is used to obtain a given weight value and obtain an initial torque current value according to the given weight value;

[0029] The power calculation module is used to obtain the calibrated actual given torque current value and the actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor;

[0030] The error calculation module is used to obtain the maximum power setting value and obtain a power error according to the maximum power setting value and the current power value of the motor;

[0031] The given torque current value calculation module is used to obtain a given torque current value according to the power error, the initial torque current value, and the power controller parameters;

[0032] The motor drive module is used to drive the motor according to the given torque current value;

[0033] The cycle limiting module is used to input the given torque current value into the power calculation module as the calibrated actual given torque current value.

[0034] Optionally, the motor drive module includes: a given voltage acquisition unit, a static axis voltage acquisition unit, a switch signal acquisition unit, and an inverter bridge;

[0035] The given voltage acquisition unit is used to perform PI controller operation on the given torque current value and the actual torque current value of the motor to obtain a given torque voltage value, and perform PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain a given excitation voltage value;

[0036] The static axis voltage acquisition unit is used to perform inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain a given α-axis voltage and a given β-axis voltage;

[0037] The switching signal acquisition unit is used to perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switching signals of the inverter bridge;

[0038] The inverter bridge is used to drive the motor according to the switching signals of the inverter bridge.

[0039] Optionally, the motor drive module further includes: a static axis current acquisition unit and a torque and excitation current value acquisition unit;

[0040] The static axis current acquisition unit is used to obtain the values of the three-phase currents of the motor, and perform CLARKE transformation on the three-phase currents of the motor to obtain the α-axis current and the β-axis current of the motor;

[0041] The torque and excitation current value acquisition unit is used to obtain the actual speed value of the motor, and perform PARK transformation on the actual speed value of the motor, the α-axis current and the β-axis current to obtain the actual torque current value and the actual excitation current value of the motor.

[0042] In the motor output power limiting method and device according to the embodiments of the present invention, in the motor output power limiting method, an initial torque current value is calculated by obtaining a given weight value, and the current power value is calculated in real time in combination with the actual speed value of the motor. The torque current value is adjusted by comparing the current power value with a preset maximum power value, so as to achieve precise control of the motor output. In the motor output power limiting method provided by the present invention, by monitoring and calculating the current power value of the motor in real time, the output power of the motor can be controlled more precisely, and the occurrence of overload phenomena can be avoided. When the motor output power exceeds the preset maximum power setting value, the power calculation and power limiting protection method can timely adjust the given torque current value to reduce the motor output power, thereby protecting the motor from overload damage. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 This is a flowchart of a motor output power limiting method provided by an embodiment of the present invention;

[0045] Figure 2 This is a flowchart of another motor output power limiting method provided by an embodiment of the present invention;

[0046] Figure 3 This is a flowchart of another motor output power limiting method provided by an embodiment of the present invention;

[0047] Figure 4 Flow chart of another method for limiting the output power of the motor provided by the embodiment of the present invention;

[0048] Figure 5 Flow chart of another method for limiting the output power of the motor provided by the embodiment of the present invention;

[0049] Figure 6 Flow chart of another method for limiting the output power of the motor provided by the embodiment of the present invention;

[0050] Figure 7 Flow chart of another method for limiting the output power of the motor provided by the embodiment of the present invention;

[0051] Figure 8 Schematic structural diagram of a device for limiting the output power of the motor provided by the embodiment of the present invention;

[0052] Figure 9 Control block diagram of a method for limiting the output power of the motor provided by the embodiment of the present invention. Detailed implementation manners

[0053] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these process, method, product or device.

[0055] Figure 1The present invention provides a flowchart of a method for limiting the output power of a motor. This embodiment is applicable to the situation where the weight adjustment of a fitness device is achieved by the output of the motor. This method can be executed by a motor output power limiting device, which can be implemented in the form of hardware and / or software. As Figure 1 shown, the method includes:

[0056] S101. Obtain a given weight value, and obtain an initial torque current value according to the given weight value. The initial torque current value is used as the calibrated actual given torque current value after being calibrated by an initial power calibration coefficient.

[0057] The initial power calibration coefficient is 1. Specifically, the system first receives the weight value input by the user, and this weight value represents the training load expected by the user. The initial torque current value is calculated according to this weight value, and the initial torque current value will be used as the basis for subsequent calibration and adjustment.

[0058] Exemplarily, obtain the corresponding initial torque current value according to the given weight value, the winding radius of the motor, and the motor torque coefficient.

[0059] Optionally, this embodiment of the present invention is applied to the weight adjustment of a fitness device. Since the weight adjustment of the fitness device is relatively fixed, usually there are only a few weight adjustment values for the fitness device, and a database of given weight values and corresponding initial torque current values can be set in advance. When executing step S101, obtain the initial torque current value by looking up the table according to the given weight value.

[0060] S102. Obtain the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0061] Specifically, the calibrated actual given torque current value is combined with the rotational speed information of the motor to calculate the current actual power value of the motor. Among them, the rotational speed information of the motor is collected by a speed sensor in the motor, that is, the rotational speed information of the motor is obtained through the speed sensor.

[0062] Exemplarily, obtain the current power value of the motor by the product of the calibrated actual given torque current value, the torque coefficient, and the actual rotational speed of the motor.

[0063] S103. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0064] Specifically, the maximum power setting value represents the maximum power output allowed by the motor. Calculate the error between the current power value and the maximum power setting value.

[0065] Exemplarily, the setting of the maximum power value is based on the specifications and performance of the device. For example, the maximum power setting value of the motor is set according to parameters such as the rated power, maximum torque, and maximum speed of the motor. In an intelligent fitness device, the user can set an appropriate maximum power value according to their actual needs, device performance, and safety considerations. At the same time, the maximum power value can be dynamic and adjusted dynamically according to the operating state of the device and the external environment. When the device detects that the temperature is too high or the load is too large, it can automatically reduce the maximum power value to avoid device damage or safety risks. The specific method for setting the maximum power value is not limited herein.

[0066] S104. Obtain a given torque current value according to the power error, the initial torque current value, and the power controller parameters.

[0067] After obtaining the power error, the initial torque current value is calibrated using the power error. According to the power error, the initial torque current value, and the parameters of the power controller, the given torque current value is calculated. The power controller can calculate the required torque current value in real time, thereby achieving precise control of the motor output. The accuracy and response speed of training are improved.

[0068] S105. Drive the motor according to the given torque current value, use the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual speed value of the motor.

[0069] The calculated given torque current value is used to drive the motor to run. At the same time, the obtained given torque current value is used as the new calibrated actual given torque current value and returned to step S102 to start a new round of loop detection and adjustment. Through this closed-loop feedback mechanism, the motor output power limiting method of the embodiments of the present invention can continuously monitor and adjust the output of the motor to ensure that the power output of the motor always remains below the maximum power setting value.

[0070] In the motor output power limiting method provided in the embodiments of the present invention, the initial torque current value is calculated by obtaining a given weight value, and the current power value is calculated in real time in combination with the actual speed value of the motor. The torque current value is adjusted by comparing the current power value with the preset maximum power value, thereby achieving precise control of the motor output. The motor output power limiting method provided in the embodiments of the present invention can adjust the torque current value in real time to prevent the motor output power from exceeding the maximum power setting value, avoiding unstable device performance caused by power fluctuations. At the same time, setting the maximum power value can effectively prevent the motor from being overloaded and avoid device damage or safety accidents caused by excessive power.

[0071] Optionally, on the basis of the above embodiments, Figure 2The flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention is as follows. Figure 2 As shown, the method for limiting the output power of a motor includes:

[0072] S201. Obtain a given weight value, and obtain an initial torque current value according to the ratio of the product of the given weight value and the motor winding radius to the motor torque coefficient. The initial torque current value is used as the calibrated actual given torque current value after being calibrated by an initial power calibration coefficient.

[0073] The initial power calibration coefficient is 1. Specifically, when obtaining the initial torque current value, the initial torque current value is obtained according to the ratio of the product of the given weight value and the motor winding radius to the motor torque coefficient. Among them, when obtaining the initial torque current value, because:

[0074] F = T / r; T = K t ×i q0 ;

[0075] Among them, F is the initial given weight value, T is the motor output torque value, r is the motor winding radius, K t is the motor torque coefficient, and i q0 is the initial torque current value.

[0076] Then, from the above expressions, the calculation expression of the initial torque current value can be deduced as:

[0077] i q0 = F × r / K t .

[0078] S202. Obtain the current actual speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the current actual speed value of the motor.

[0079] S203. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0080] S204. Obtain the given torque current value according to the power error, the initial torque current value, and the power controller parameters.

[0081] S205. Drive the motor according to the given torque current value, use the given torque current value as the calibrated actual given torque current value, and return to execute the step of obtaining the current actual speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the current actual speed value of the motor.

[0082] Optionally, on the basis of the above embodiments, Figure 3 The flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention is as follows. Figure 3 As shown, the method for limiting the output power of a motor includes:

[0083] S301. Obtain a given weight value, and obtain an initial torque current value according to the given weight value. After being calibrated by the initial power calibration coefficient, the initial torque current value is used as the calibrated actual given torque current value.

[0084] Wherein the initial power calibration coefficient is 1.

[0085] S302. Obtain the current actual rotation speed value of the motor, and obtain the current power value of the motor according to the product of the calibrated actual given torque current value, the motor torque coefficient, the motor rotation speed, and the conversion coefficient.

[0086] Wherein the conversion coefficient is 0.1047.

[0087] Specifically, the calculation expression of the current power value of the motor is:

[0088] P = T × W × 0.1047;

[0089] Wherein, P is the current power value of the current motor, T is the motor output torque value, and W is the motor rotation speed.

[0090] S303. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0091] S304. Obtain the given torque current value according to the power error, the initial torque current value, and the power controller parameters.

[0092] S305. Drive the motor according to the given torque current value, use the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual rotation speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotation speed value of the motor.

[0093] Optionally, on the basis of the above embodiments, Figure 4 This is a flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention. As Figure 4 shown, the method for limiting the output power of the motor includes:

[0094] S401. Obtain a given weight value, and obtain an initial torque current value according to the given weight value. After being calibrated by the initial power calibration coefficient, the initial torque current value is used as the calibrated actual given torque current value.

[0095] Wherein the initial power calibration coefficient is 1.

[0096] S402. Obtain the current actual rotation speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotation speed value of the motor.

[0097] S403. Obtain the maximum power setting value, and obtain the power error based on the difference between the maximum power setting value and the current power value of the motor.

[0098] Specifically, the calculation expression of the power error is:

[0099] e(t) = P max - P;

[0100] where P max is the maximum power setting value, P is the current power value of the current motor, and e(t) is the power error.

[0101] S404. Obtain the given torque current value based on the power error, the initial torque current value, and the power controller parameters.

[0102] S405. Drive the motor according to the given torque current value, use the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0103] Optionally, on the basis of the above embodiments, Figure 5 The following is a flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention. As Figure 5 shown, the method for limiting the output power of a motor includes:

[0104] S501. Obtain the given weight value, obtain the initial torque current value according to the given weight value, and use the initial torque current value as the calibrated actual given torque current value after being calibrated by the initial power calibration coefficient.

[0105] Wherein the initial power calibration coefficient is 1.

[0106] S502. Obtain the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0107] S503. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0108] S504. Obtain the given torque current value according to the first expression group among the power error, the calibrated actual given torque current value, the power controller parameters, and the fixed torque current value.

[0109] Specifically, the first expression group includes:

[0110]

[0111] Where K p is the controller proportional parameter, K iis the integral parameter of the controller, k is the power calibration coefficient, and i q0 is the initial torque current value, and I q is the given torque current value.

[0112] S505. Drive the motor according to the given torque current value, use the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0113] Optionally, based on the above embodiments, Figure 6 is a flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention. As Figure 6 shown, the method for limiting the output power of a motor includes:

[0114] S601. Obtain the given weight value, obtain the initial torque current value according to the given weight value, and use the initial torque current value as the calibrated actual given torque current value after being calibrated by the initial power calibration coefficient.

[0115] Wherein the initial power calibration coefficient is 1.

[0116] S602. Obtain the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0117] S603. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0118] S604. Obtain the given torque current value according to the power error, the initial torque current value, and the power controller parameters.

[0119] S605. Use the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0120] S606. Perform PI controller operation on the given torque current value and the actual torque current value of the motor to obtain the given torque voltage value, and perform PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain the given excitation voltage value.

[0121] Specifically, the PI controller is a proportional-integral controller, which is a feedback controller. By adjusting the output of the control system, the actual output of the system is made as close as possible to the desired output, thereby achieving the control goal. In motor drive, the PI controller is used to maintain the torque and excitation of the motor near the given values. Optionally, by adjusting the parameters of the PI controller, the starting, running, and stopping processes of the motor can be optimized.

[0122] S607. Perform an inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and the given β-axis voltage.

[0123] Specifically, perform an inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and the given β-axis voltage.

[0124] The inverse PARK transformation is the inverse process of the PARK transformation. The inverse PARK transformation converts the DC parameters in the fixed coordinate system back to the AC parameters in the rotating coordinate system. In motor control, the inverse PARK transformation is used to convert the given torque voltage value and the given excitation voltage value from the d-flux axis - q-torque axis coordinate system back to the α-β coordinate system.

[0125] S608. Perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switching signals of the inverter bridge; drive the motor according to the switching signals of the inverter bridge.

[0126] Space vector pulse width modulation (SVPWM) is an efficient modulation technique mainly applied to inverters and motor drive systems. Space vector pulse width modulation controls the three-phase voltage vectors to be close to the ideal DC voltage to improve the conversion efficiency and output voltage quality while reducing harmonics. Convert the AC voltage value obtained by the inverse PARK transformation into the switching signals that the inverter bridge can understand, so as to drive the motor to operate. The space vector pulse width modulation technique can improve the operating efficiency and dynamic performance of the motor and reduce harmonic distortion.

[0127] Based on the above embodiments, Figure 7 is a flowchart of another method for limiting the output power of a motor provided by an embodiment of the present invention. As Figure 7 shown, the method for limiting the output power of a motor includes:

[0128] S701. Obtain the given weight value, and obtain the initial torque current value according to the given weight value. The initial torque current value is used as the calibrated actual given torque current value after being calibrated by the initial power calibration coefficient.

[0129] Wherein the initial power calibration coefficient is 1.

[0130] S702. Obtain the current actual speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual speed value of the motor.

[0131] S703. Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor.

[0132] S704. Obtain the given torque current value according to the power error, the initial torque current value, and the power controller parameters.

[0133] S705. Take the given torque current value as the calibrated actual given torque current value and return to execute the step of obtaining the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

[0134] S706. Obtain the values of the three-phase currents of the motor; perform CLARKE transformation on the three-phase currents of the motor to obtain the α-axis current and β-axis current of the motor.

[0135] Perform CLARKE transformation on the three-phase current values Ia, Ib, and Ic to convert them into the current values Iα and Iβ in the two-phase stationary coordinate system (α-β coordinate system).

[0136] Exemplarily, the formula for CLARKE transformation is: Iα = Ia;

[0137] Among them, the A-phase current Ia directly corresponds to the α-axis, and the B and C phases are transformed to the β-axis through geometric relations.

[0138] S707. Obtain the actual rotational speed value of the motor, and perform PARK transformation on the actual rotational speed value of the motor, α-axis current, and β-axis current to obtain the actual torque current value and actual excitation current value of the motor.

[0139] Specifically, perform PARK transformation on the current values Iα and Iβ in the two-phase stationary coordinate system α-β coordinate system obtained by CLARKE transformation and the actual rotational speed value of the motor to convert them into the current values Id and Iq in the rotating coordinate system d-q coordinate system.

[0140] Exemplarily, the formula for PARK transformation is: Id = Iαcos(θ) + Iβsin(θ);

[0141] Iq = -Iαsin(θ) + Iβcos(θ). Among them, θ is the rotor position angle of the motor, the direct axis is aligned with the magnetic field of the rotor, and the quadrature axis is perpendicular to the magnetic field.

[0142] After PARK transformation, the obtained current components Id and Iq respectively represent the excitation current component and torque current component of the motor. The excitation current Id controls the magnetic flux of the motor, and the torque current Iq controls the torque of the motor.

[0143] S708. Perform PI controller operation on the given torque current value and the actual torque current value of the motor to obtain the given torque voltage value, and perform PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain the given excitation voltage value.

[0144] S709. Perform inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and given β-axis voltage.

[0145] The S710 obtains the switching signals of the inverter bridge through space vector pulse width modulation based on the given α-axis voltage and the given β-axis voltage; and drives the motor according to the switching signals of the inverter bridge.

[0146] Figure 8 As shown in the structure schematic diagram of a motor output power limiting device provided by an embodiment of the present invention, Figure 8 as shown, the motor output power limiting device includes:

[0147] A weight-torque conversion module 801, a power calculation module 802, an error calculation module 803, a given torque current value calculation module 804, a cycle limit module 805, and a motor drive module 806; the weight-torque conversion module 801 is configured to obtain a given weight value and obtain an initial torque current value according to the given weight value; the power calculation module 802 is configured to obtain a calibrated actual given torque current value and an actual motor speed value, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual motor speed value; the error calculation module 803 is configured to obtain a maximum power setting value and obtain a power error according to the maximum power setting value and the current power value of the motor; the given torque current value calculation module 804 is configured to obtain a given torque current value according to the power error, the initial torque current value, and the power controller parameters; the motor drive module 806 is configured to drive the motor according to the given torque current value; the cycle limit module 805 is configured to input the given torque current value into the power calculation module 802 as the calibrated actual given torque current value.

[0148] The motor drive module 806 includes: a given voltage acquisition unit 8061, a static axis voltage acquisition unit 8062, a switching signal acquisition unit 8063, and an inverter bridge 8064; the given voltage acquisition unit 8061 is configured to perform PI controller operations on the given torque current value and the actual torque current value of the motor to obtain a given torque voltage value, and perform PI controller operations on the given excitation current value and the actual excitation current value of the motor to obtain a given excitation voltage value; the static axis voltage acquisition unit 8062 is configured to perform an inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain a given α-axis voltage and a given β-axis voltage; the switching signal acquisition unit 8063 is configured to perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switching signals of the inverter bridge 8064; the inverter bridge 8064 is configured to drive the motor according to the switching signals of the inverter bridge 8064.

[0149] The motor drive module 806 further includes: a static shaft current acquisition unit 8065 and a torque and excitation current value acquisition unit 8066; the static shaft current acquisition unit 8065 is configured to obtain the values of the three-phase currents of the motor, and the three-phase currents of the motor are subjected to CLARKE transformation to obtain the α-axis current and the β-axis current of the motor; the torque and excitation current value acquisition unit 8066 is configured to obtain the actual rotational speed value of the motor, and the actual rotational speed value of the motor, the α-axis current and the β-axis current are subjected to PARK transformation to obtain the actual torque current value and the actual excitation current value of the motor.

[0150] A motor output power limiting device provided by an embodiment of the present invention is used to execute the motor output power limiting method of any of the above embodiments of the present invention, and has the beneficial effects of the motor output power limiting method of any of the above embodiments of the present invention.

[0151] Figure 9 It is a control block diagram of a motor output power limiting method provided by an embodiment of the present invention, as Figure 9 shown, the motor output power limiting method includes:

[0152] In the weight / moment conversion module, an initial torque current value is obtained according to a given weight value, a motor winding radius, and a motor moment and sent to the power controller. The initial torque current value is used as a calibrated actual given torque current value after being calibrated by an initial power calibration coefficient, and the calibrated actual given torque current value is sent to the power calculation module, where the initial power calibration coefficient is 1.

[0153] The calculation expression for obtaining the initial torque current value is: i q0 = F × r / K t where F is the initial given weight value, T is the motor output torque value, r is the motor winding radius, Kt is the motor torque coefficient, and iq0 is the initial torque current value.

[0154] In the power calculation module, the current power value of the motor is obtained according to the product of the calibrated actual given torque current value, the motor torque coefficient, the motor speed, and the conversion coefficient. The calculation expression for the current power value of the motor is: P = T × W × 0.1047. Where P is the current power value of the current motor, T is the motor output torque value, and W is the motor speed. Wherein, when obtaining the motor speed, after the speed sensor obtains the speed of the motor, the motor speed is sent to the power calculation module.

[0155] The difference between the obtained current power value of the motor and the maximum power setting value is obtained as the power error. In the power controller, a given torque current value is obtained according to the first expression group among the power error, the calibrated actual given torque current value, the power controller parameters, and the fixed torque current value. The first expression group includes:

[0156] Iq = i q0 × k; where Kp is the proportional parameter of the controller, Ki is the integral parameter of the controller, k is the power calibration coefficient, iq0 is the initial torque current value, and Iq is the given torque current value.

[0157] The given torque current value and the actual torque current value of the motor are subjected to PI controller operation to obtain the given torque voltage value, and the given excitation current value and the actual excitation current value of the motor are subjected to PI controller operation to obtain the given excitation voltage value. Optionally, the given excitation current value is 0. The given torque voltage value and the given excitation voltage value are subjected to inverse PARK transformation to obtain the given α-axis voltage and the given β-axis voltage; the given α-axis voltage and the given β-axis voltage are subjected to space vector pulse width modulation to obtain the switching signals of the inverter bridge; the motor is driven according to the switching signals of the inverter bridge.

[0158] When obtaining the actual torque current value and the actual excitation current value of the motor, the values of the three-phase current of the motor are obtained; the three-phase current of the motor is subjected to CLARKE transformation to obtain the α-axis current and the β-axis current of the motor; the actual speed value of the motor is obtained, and the actual speed value of the motor, the α-axis current and the β-axis current are subjected to PARK transformation to obtain the actual torque current value and the actual excitation current value of the motor.

[0159] In the method for limiting the output power of the motor according to the embodiments of the present invention, it includes a power calculation and power limit protection method and a motor driving method. Among them, in the power calculation method, the current power value of the motor is calculated in real time and compared with a preset maximum power setting value, so as to realize the limitation and protection of the motor output power. It includes: calculating the initial torque current value according to the given weight value, the motor winding radius and the motor torque coefficient; through the power calculation module, combining the calibrated actual given torque current value, the motor speed and the conversion coefficient to calculate the current power value of the motor; comparing the current power value with the maximum power setting value to obtain the power error; finally, according to the power error, the calibrated actual given torque current value and the power controller parameters, adjusting the given torque current value to achieve precise control of the motor output power. The motor driving method mainly realizes precise control of the motor torque and excitation through the PI controller and the space vector pulse width modulation technology. In the motor driving method, the given torque current value and the actual torque current value of the motor are operated by the PI controller to obtain the given torque voltage value; the given excitation current value and the actual excitation current value of the motor are operated by the PI controller to obtain the given excitation voltage value; the inverse PARK transformation is performed on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and the given β-axis voltage; finally, through the space vector pulse width modulation technology, the given α-axis voltage and the given β-axis voltage are converted into the switching signals of the inverter bridge, so as to drive the motor to operate. In the method for limiting the output power of the motor according to the embodiments of the present invention, by real-time monitoring and calculating the current power value of the motor, the output power of the motor can be controlled more precisely, and the occurrence of overload phenomena can be avoided. When the motor output power exceeds the preset maximum power setting value, the power calculation and power limit protection method can timely adjust the given torque current value to reduce the motor output power, so as to protect the motor from overload damage.

[0160] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0161] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for limiting the output power of a motor, characterized in that, Including: Obtain a given weight value, and obtain an initial torque current value according to the given weight value. The initial torque current value is used as the calibrated actual given torque current value after being calibrated by an initial power calibration coefficient, where the initial power calibration coefficient is 1; Obtain the current actual rotational speed value of the motor, and obtain the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor; Obtain the maximum power setting value, and obtain the power error according to the maximum power setting value and the current power value of the motor; Obtain the calibrated actual given torque current value according to the power error, the initial torque current value, and the power controller parameters; Drive the motor according to the calibrated actual given torque current value, and return the calibrated actual given torque current value to execute the step of obtaining the current actual rotational speed value of the motor, and obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor.

2. The method for limiting the output power of an electric motor according to claim 1, characterized in that The obtaining the initial torque current value according to the given weight value includes: Obtain the initial torque current value according to the ratio of the product of the given weight value and the winding radius of the motor to the motor torque coefficient.

3. The method for limiting the output power of a motor according to claim 1, wherein The obtaining the current power value of the motor according to the calibrated actual given torque current value and the actual rotational speed value of the motor includes: Obtain the current power value of the motor according to the product of the calibrated actual given torque current value, the motor torque coefficient, the motor rotational speed, and the conversion coefficient; where the conversion coefficient is 0.1047.

4. The method for limiting the output power of the motor according to claim 1, characterized in that, The obtaining the power error according to the maximum power setting value and the current power value of the motor includes: Obtain the power error according to the difference between the maximum power setting value and the current power value of the motor.

5. The method for limiting the output power of a motor according to claim 1, wherein The obtaining the given torque current value according to the power error, the initial torque current value, and the power controller parameters includes: Obtain the given torque current value according to the first expression group among the power error, the calibrated actual given torque current value, the power controller parameters, and the fixed torque current value; The first expression group includes: Iq = i q0 × k; Among them, K p is the proportional parameter of the controller, K i is the integral parameter of the controller, k is the power calibration coefficient, i q0 is the initial torque current value, I q is the given torque current value.

6. The method for limiting the output power of an electric motor according to claim 1, characterized in that The driving the motor according to the given torque current value includes: Perform a PI controller operation on the given torque current value and the actual torque current value of the motor to obtain a given torque voltage value, and perform a PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain a given excitation voltage value; Perform an inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain a given α-axis voltage and a given β-axis voltage; Perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switching signals of the inverter bridge; drive the motor according to the switching signals of the inverter bridge.

7. The method for limiting the output power of an electric motor according to claim 6, characterized in that, Before performing a PI controller operation on the given torque current value and the actual torque current value of the motor to obtain a given torque voltage value, and performing a PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain a given excitation voltage value, it further includes: Obtain the values of the three-phase current of the motor; perform a CLARKE transformation on the three-phase current of the motor to obtain the α-axis current and the β-axis current of the motor; Obtain the actual motor speed value, and perform PARK transformation on the actual motor speed value, the α-axis current, and the β-axis current to obtain the actual torque current value and the actual excitation current value of the motor.

8. A motor output power limiting device, characterized in that, It includes: A weight torque conversion module, a power calculation module, an error calculation module, a given torque current value calculation module, a motor drive module, and a cycle limit module; The weight torque conversion module is used to obtain a given weight value and obtain an initial torque current value according to the given weight value; The power calculation module is used to obtain the calibrated actual given torque current value and the actual motor speed value, and obtain the current motor power value according to the calibrated actual given torque current value and the actual motor speed value; The error calculation module is used to obtain the maximum power setting value and obtain the power error according to the maximum power setting value and the current motor power value; The fixed torque current value calculation module is used to obtain the given torque current value according to the power error, the initial torque current value, and the power controller parameters; The motor drive module is used to drive the motor according to the given torque current value; The cycle limit module is used to input the given torque current value into the power calculation module as the calibrated actual given torque current value.

9. The motor output power limiting device according to claim 8, characterized in that, The motor drive module includes: a given voltage acquisition unit, a static axis voltage acquisition unit, a switch signal acquisition unit, and an inverter bridge; The given voltage acquisition unit is used to perform PI controller operation on the given torque current value and the actual torque current value of the motor to obtain the given torque voltage value, and perform PI controller operation on the given excitation current value and the actual excitation current value of the motor to obtain the given excitation voltage value; The static axis voltage acquisition unit is used to perform inverse PARK transformation on the given torque voltage value and the given excitation voltage value to obtain the given α-axis voltage and the given β-axis voltage; The switch signal acquisition unit is used to perform space vector pulse width modulation on the given α-axis voltage and the given β-axis voltage to obtain the switch signal of the inverter bridge; The inverter bridge is used to drive the motor according to the switch signal of the inverter bridge.

10. The motor output power limiting device according to claim 9, wherein, The motor drive module further includes: a static axis current acquisition unit and a torque and excitation current value acquisition unit; The static axis current acquisition unit is used to obtain the values of the three-phase currents of the motor, and perform CLARKE transformation on the three-phase currents of the motor to obtain the α-axis current and the β-axis current of the motor; The torque and excitation current value acquisition unit is used to obtain the actual motor speed value, and perform PARK transformation on the actual motor speed value, the α-axis current, and the β-axis current to obtain the actual torque current value and the actual excitation current value of the motor.

Images