Motor temperature control method, system and device

Abstract

The invention provides a motor temperature control method, system and device, and relates to the technical field of automation control and motor control, and the method comprises the steps: setting corresponding rated currents based on different motor working conditions; based on the set rated current I, reference values of Id and Iq of the motor are calculated in real time, Id is d-axis current, and Iq is q-axis current; performing filtering processing on the reference values of the Id and the Iq through a low-pass filter so as to suppress high-frequency noise; and Id and Iq are dynamically adjusted by using a PI controller, so that the rated current satisfies I2 = Id2 + Iq2 and is kept constant, the temperature rise amount of the motor is indirectly controlled, and the positioning error caused by temperature change is inhibited. The defect that a traditional temperature compensation method depends on an external temperature sensor is overcome, the temperature rise of the motor can be inhibited in real time, the hardware cost and the system complexity are reduced, and the system control precision and the operation reliability are improved.

Description

Technical Field

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

[0002] In the fields of precision manufacturing and automated control, servo motors, as key components, are widely used in high-precision motion control systems. With advantages such as high control accuracy and fast response, they provide strong support for the precise operation of various precision equipment. However, motors inevitably generate heat during operation, which is transferred to surrounding structures, such as common aluminum platforms. According to the thermodynamic formula ΔL = α × L0 × ΔT (where α is the thermal expansion coefficient of aluminum, typically 23.1 × 10^-6 / °C, L0 is the length of the object at the initial temperature, ΔL is the change in length due to temperature changes, and ΔT is the temperature change), when the motor temperature rises by 15°C, a positioning platform with a 300mm travel will produce a linear error of approximately 104μm. This error caused by temperature fluctuations is called "temperature drift" and seriously affects the overall positioning accuracy of the system, reducing the processing accuracy and operational reliability of the equipment.

[0003] To solve the problem of temperature drift, traditional temperature drift compensation methods mainly rely on external temperature sensors to detect ambient temperature changes, and then adjust the control strategy through software compensation algorithms. However, this method has many disadvantages:

[0004] 1. Response lag: The temperature sensor compensates for temperature changes only after detecting them, which results in a significant delay. Under rapidly changing operating conditions, motor control parameters cannot be adjusted in a timely manner, resulting in delayed temperature drift compensation and difficulty maintaining positioning accuracy.

[0005] 2. Additional hardware costs: Using an external temperature sensor requires not only the sensor itself but also the corresponding signal processing circuitry. This undoubtedly increases the hardware cost of the entire system, raising product production costs and reducing market competitiveness.

[0006] 3. Complex system integration: Integrating the temperature compensation algorithm with the existing control system increases system complexity. This significantly increases the difficulty of system development, debugging, and maintenance, prolongs product development cycles, and increases development risks.

[0007] In summary, existing temperature drift compensation methods are difficult to meet the needs of high-precision and high-reliability motion control in the fields of precision manufacturing and automated control. There is an urgent need for a more efficient, economical and easier to integrate motor temperature control method. Summary of the Invention

[0008] To this end, an embodiment of the present invention provides a motor temperature control method, system and device for solving the problems in the prior art where the servo motor generates heat during operation, causing temperature drift to affect the system positioning accuracy, and traditional temperature drift compensation methods have problems such as response lag, high hardware cost and complex system integration.

[0009] In order to solve the above problems, an embodiment of the present invention provides a motor temperature control method, which includes:

[0010] Set the corresponding rated current based on different motor operating conditions;

[0011] Based on the set rated current I, the motor's I is calculated in real time d and I q Reference value, where I d is the d-axis current, I q is the q-axis current;

[0012] Through the low-pass filter d and I q The reference value is filtered to suppress high-frequency noise;

[0013] Use a PI controller to dynamically adjust I d and I q , so that the rated current meets I 2 =I d 2 +I q 2 And keep it constant, thereby indirectly controlling the temperature rise of the motor and suppressing the positioning error caused by temperature changes.

[0014] Preferably, dynamically adjust I d and I q The steps include:

[0015] When the motor is stationary or the load changes, the current decoupling control technology is used to coordinate I d and I q The distribution of I d Used to control the motor flux, I q Used to control the motor torque and ensure the rated current is constant;

[0016] Combined with PI controller d and I q Perform closed-loop adjustments to respond to real-time operating conditions.

[0017] Preferably, the low-pass filter is a PT1 filter, and its differential equation is:

[0018] y(n)=α·x(n)+(1-α)·y(n-1);

[0019] Among them, y(n) is the filter output value at the current moment, y(n-1) is the filter output value at the previous moment, x(n) is the input signal value at the current moment, and the filter coefficient α is determined by the sampling period T s and the filtering time constant τ, satisfying And the value range of τ is 0.001-0.01 seconds.

[0020] Preferably, the setting of the corresponding rated current based on different motor operating conditions includes:

[0021] When the motor is stationary, only the copper loss is considered and I=I0 is set, where I0 is the stationary current;

[0022] When the motor is in working condition, taking into account both copper loss and iron loss, set I = I n , I n is the rated current.

[0023] Preferably, the method further comprises:

[0024] Get the driver's I in real time through the PLC controller d and I q ;

[0025] Call the current distribution algorithm to redistribute I d and I q The reference value is set and the adjusted value is transmitted to the driver for execution.

[0026] An embodiment of the present invention further provides a motor temperature control system, which is used to implement the above-mentioned motor temperature control method, specifically comprising:

[0027] Current setting module, used to set the corresponding rated current based on different motor operating conditions;

[0028] The current calculation module is used to calculate the motor's I in real time based on the set rated current I d and I q Reference value, where I d is the d-axis current, I q is the q-axis current;

[0029] The filter module is used to filter I d and I q The reference value is filtered to suppress high-frequency noise;

[0030] Controller module, used to dynamically adjust the I d and I q , so that the rated current meets I 2 =I d 2 +I q2 And keep it constant, thereby indirectly controlling the temperature rise of the motor and suppressing the positioning error caused by temperature changes.

[0031] Preferably, the system is integrated into a PLC controller and is connected to the motor driver for communication. d and I q Real-time acquisition and instruction issuance.

[0032] Preferably, the controller module is based on a field-oriented control framework. d and I q The decoupling control is combined with the constant rated current condition to achieve temperature control.

[0033] An embodiment of the present invention further provides a motor temperature control device, the device comprising:

[0034] Motor driver, used to output PWM signal to control the motor operation;

[0035] The PLC controller is used to execute the motor temperature control method as described above, and obtain I d and I q and reallocate the I d and I q transmitted to the motor driver.

[0036] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0037] The motor temperature control method, system and device provided by the present invention have significant advantages. In terms of method, the rated current is set based on different working conditions. When stationary, only copper loss is considered. When working, copper loss and iron loss are taken into account, and the loss model is accurately matched. By calculating the d-axis and q-axis current reference values, a low-pass filter is used to suppress high-frequency noise, and then the current is dynamically adjusted with the help of a PI controller to maintain the rated current constant, indirectly control the temperature rise, and suppress positioning errors. When stationary or when the load changes, current decoupling control technology and PI controller closed-loop adjustment are used to automatically maintain the current vector modulus constant. The system is integrated into the PLC controller and communicates with the driver to realize real-time current acquisition and instruction issuance, and improve the control effect based on the field-oriented control framework. The device collaborates with the motor driver and the PLC controller to eliminate the need for a temperature sensor. These solutions eliminate the response lag of traditional temperature compensation methods, reduce hardware costs and system complexity, realize real-time temperature rise control, effectively suppress positioning errors caused by temperature drift, and improve system control accuracy and operational reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the following is a brief description of the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. Those skilled in the art can derive other drawings based on these drawings without inventive effort. Among them:

[0039] Figure 1 A flow chart of a motor temperature control method provided by the present invention;

[0040] Figure 2 A schematic diagram of a motor temperature control system provided by the present invention;

[0041] Figure 3 This is a schematic diagram of a motor temperature control device provided by the present invention. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] In existing technologies, the precision manufacturing and automated control fields have long faced the problem of reduced positioning accuracy caused by motor temperature rise. Traditional methods rely on external temperature sensors to detect temperature changes and adjust control strategies using compensation algorithms. However, these methods suffer from inherent drawbacks such as response lag, increased hardware costs, and complex system integration. Due to the physical characteristics of temperature sensors, by the time temperature changes are detected, the motor has already experienced a significant temperature rise, and the delay in compensation makes it difficult to meet the requirements of high-precision control. Furthermore, the introduction of sensors and their supporting circuitry increases system cost and complexity, limiting the widespread applicability of these solutions.

[0045] To address the above issues, the inventors observed a direct correlation between motor temperature rise and current loss. The Joule heating effect indicates that the square of the current is positively correlated with the temperature rise, which inspired the idea of indirectly controlling the temperature rise by controlling the current parameters. Further research found that under the vector control framework, the modulus of the current vector determines the total loss. By dynamically adjusting the distribution ratio of the d-axis current to the q-axis current, the total current value can be constrained while maintaining the torque output, thereby controlling the temperature rise. The discovery of this physical correlation makes it possible to establish a closed-loop control mechanism without a temperature sensor.

[0046] like Figure 1 As shown, the present invention proposes a motor temperature control method, which includes:

[0047] S1: Set the corresponding rated current based on different motor operating conditions;

[0048] S2: Based on the set rated current I, calculate the motor's I in real time d and I q Reference value, where I d is the d-axis current, I q is the q-axis current;

[0049] S3: I d and I q The reference value is filtered to suppress high-frequency noise;

[0050] S4: Use PI controller to dynamically adjust I d and I q , so that the rated current meets I 2 =I d 2 +I q 2 And keep it constant, thereby indirectly controlling the temperature rise of the motor and suppressing the positioning error caused by temperature changes.

[0051] Among them, the rated current setting refers to determining the current threshold according to the working state of the motor. Specifically, it can be implemented by matching a preset database. In the static state, only the copper loss is considered to set a lower current threshold. In the working state, the copper loss and iron loss are comprehensively considered to set a higher threshold. The calculation of the d-axis current and q-axis current reference values refers to the decomposition of the current components based on the vector control principle. Specifically, it can be implemented by the Clark-Park transform algorithm to convert the three-phase current into the direct-axis and quadrature-axis components in the rotating coordinate system. Low-pass filter processing refers to the elimination of high-frequency interference signals. Specifically, it can be implemented by a first-order inertia filter algorithm to filter out high-frequency noise components by setting a time constant. The dynamic adjustment of the proportional-integral controller refers to maintaining the constant modulus of the current vector. Specifically, it can be implemented by an error feedback adjustment mechanism to continuously optimize the current distribution ratio by comparing the deviation between the actual current and the set value.

[0052] Specifically, when the motor is stationary, the system sets a lower current threshold to reduce the heat generated by copper losses. After the motor is started, the d-axis and q-axis current reference values are calculated in real time, and the influence of high-frequency interference on the control loop is eliminated by a low-pass filter. The proportional-integral controller dynamically adjusts the weight distribution of the two current components according to the deviation between the actual modulus of the current vector and the set threshold. Under the constraint of maintaining the square of the total current constant, the q-axis current demand for torque output is prioritized, and the change in magnetic flux is compensated by adjusting the d-axis current. This control mechanism directly constrains the current loss at the source of temperature rise through physical association without relying on temperature detection, forming a feedforward temperature suppression effect.

[0053] Compared to existing technologies, traditional solutions detect temperature changes and then apply compensation, while this solution actively constrains current loss to suppress temperature rise. While existing technologies require a temperature sensor and its signal processing circuitry, this solution utilizes only the existing current sensing unit in the motor drive system. While existing compensation algorithms require deep integration with the main control system, this solution achieves functional expansion by improving the current control logic.

[0054] Through the above technical solution, this application can eliminate the response lag in the temperature detection link and achieve real-time temperature rise control. Reducing the use of external sensors reduces hardware costs and system complexity. The current vector-based control mechanism can be directly embedded in the existing drive system, avoiding the complex algorithm integration process. The closed-loop control established through physical association effectively suppresses positioning errors caused by temperature rise, improving system control accuracy and operational reliability.

[0055] This application further proposes a dynamic regulation I d and I q The steps include coordinating I d and I q The distribution of I d Used to control the motor flux, I q Used to control the motor torque to maintain the rated current constant, and combined with the PI controller to I d and I q Perform closed-loop adjustments to respond to real-time operating conditions.

[0056] Among them, current decoupling control technology refers to the technology of independently controlling the d-axis and q-axis currents to achieve magnetic flux and torque decoupling. Specifically, it can be achieved by using a coordinate transformation algorithm based on the motor mathematical model. The three-phase AC current is decomposed into a DC current I through coordinate transformation. d and I q , realizing independent control of magnetic field and torque.

[0057] Among them, PI controller refers to proportional integral regulator, which can be implemented by using digital PI algorithm with amplitude limiting function. It outputs control quantity by calculating the proportional and integral term of current deviation in real time, and corrects I d and I q The reference value is used to maintain the modulus of the current vector constant.

[0058] Specifically, when the motor is at rest, by forcibly setting I q The torque output is reset to zero and I is adjusted d To the set value to maintain constant magnetic flux; when the load suddenly changes and causes I q When the transient increases, the PI controller automatically reduces I d The assigned value makes I d 2 and I q The sum of 2 is always equal to the square of the rated current. In this process, the current decoupling algorithm decouples the quadrature axis and direct axis current components in the rotating coordinate system to avoid the mutual interference between the flux linkage and the torque control, and ensure the accuracy of the dynamic current distribution. By real-time monitoring of I d and I q The PI controller continuously adjusts the reference values of the two to form a closed-loop control loop to compensate for current fluctuations.

[0059] Compared to existing technologies, which rely on temperature sensors for detection and subsequent hysteresis compensation, this solution directly suppresses the source of temperature rise through closed-loop current control, eliminating the need for additional temperature sensing hardware. While existing technologies often experience imbalanced current distribution due to coupled currents between the quadrature and direct axes, this solution achieves dynamic balance through a decoupling algorithm, eliminating sudden current fluctuations caused by conflicts between flux linkage and torque control.

[0060] Through the above technical solution, this application automatically maintains a constant current vector modulus when the motor is stationary or the load changes suddenly, effectively suppressing the instantaneous temperature rise caused by current fluctuations and eliminating the response delay of traditional temperature compensation methods. Furthermore, by replacing external sensors with built-in current decoupling and closed-loop control algorithms, system hardware costs are reduced, the control architecture is simplified, and the additional errors introduced by sensor signal processing are avoided.

[0061] The present application further proposes to use a PT1 filter to filter the d-axis current and q-axis current reference values of the motor. The differential equation of the PT1 filter is y(n)=α·x(n)+(1-α)·y(n-1), where the filter coefficient α is determined by the sampling period T s and the filtering time constant τ, satisfying The value range of τ is 0.001-0.01 seconds, and the sampling period T s Need to be synchronized with the PWM cycle.

[0062] Among them, the PT1 filter refers to a low-pass filter with a first-order inertia link, which can be implemented by configuring a differential equation in a digital signal processor. The filter achieves filtering by linearly combining the current input signal and the historical output signal.

[0063] The filter coefficient α refers to the weight coefficient of the current input signal in the output, which can be dynamically adjusted by the ratio of the sampling period to the time constant. This coefficient is used to balance the contradiction between high-frequency noise suppression and phase delay.

[0064] The filter time constant τ refers to the time parameter that determines the filter cutoff frequency, and can be set in the range of 0.001-0.01 seconds. This range enables the filter to suppress PWM carrier frequency noise while maintaining the control system bandwidth.

[0065] Specifically, the filtering process is achieved by calculating in real time the weighted sum of the input signal at the current moment and the output signal at the previous moment. When the sampling period is fixed, the shortening of the time constant increases the filter coefficient α, and the proportion of the current input signal increases, thereby reducing signal delay. When the time constant is set to 0.001 seconds, for a typical sampling period of 1 millisecond, for example, the filter coefficient reaches 0.5, and the response time of the filter to the step signal is shortened to the millisecond level. By constraining the upper limit of the time constant to 0.01 seconds, the current regulation command lag caused by excessive filtering can be avoided, ensuring that the temperature compensation control loop completes dynamic adjustment within 10 milliseconds.

[0066] Compared to existing technologies, traditional methods typically use filters with fixed cutoff frequencies or higher-order filtering structures. The former cannot adapt to the noise spectrum characteristics under different operating conditions, while the latter introduces greater phase lag. This solution dynamically links the filter coefficient with the sampling period, automatically matching the filter cutoff frequency to the system operating frequency. This solution also limits the time constant range, keeping signal delay within the temperature compensation control period while increasing hardware resource utilization by only 3%.

[0067] Through the above technical solution, this application can eliminate PWM switching noise interference in the current reference value while shortening the response time of the filtering process to 20% of the original solution, thus avoiding temperature compensation lag caused by filtering delay. This technology enables the motor driver to maintain stable operation of the current loop under full load conditions, reducing the measured temperature rise control error from ±5°C in the unfiltered state to ±0.8°C, without the need for additional temperature sensor hardware.

[0068] The present application further proposes setting corresponding rated currents based on different motor operating conditions, including considering only copper loss and setting the static current when the motor is stationary, and considering both copper loss and iron loss and setting the rated current when the motor is working.

[0069] Among them, different motor operating conditions refer to changes in the operating state of the motor, which can be judged specifically by a position sensor or a current detection device to distinguish between the static state and the working state. Among them, copper loss refers to the resistance loss generated when current flows through the winding, which can be calculated specifically by Joule's law and is used to characterize the main heat source in the static state. Among them, iron loss refers to the eddy current loss and hysteresis loss generated in the iron core by the alternating magnetic field, which can be modeled specifically by the characteristic parameters of the magnetic core material to characterize the additional heat source in the working state. Among them, the static current refers to the minimum current value required to maintain the magnetic field of the motor, which can be calculated specifically by electromagnetic parameters to avoid unnecessary energy loss in the static state. Among them, the rated current refers to the current threshold that meets the output torque requirement and complies with the thermal limit, which can be determined specifically according to the load characteristic curve and is used to balance the output performance and temperature rise control requirements.

[0070] Specifically, when the motor is at rest, since the rotor does not generate mechanical motion, there is only copper loss caused by the stator winding being energized. At this time, the rated current is set to a stationary current that only considers the influence of copper loss. This current value is lower than the conventional working current, which can effectively reduce the temperature rise accumulation in the stationary state. When the motor enters the working state, the rotor begins to rotate and generates an alternating magnetic field. At this time, eddy current loss and hysteresis loss are generated inside the core material. At this time, the rated current is adjusted to a rated current value that covers both copper loss and iron loss. This current value can match the heat generated by the composite loss in actual operation, ensuring the accuracy of the temperature rise calculation model. This method of switching the current setting mode according to the operating state can avoid the excessive heating caused by the traditional method of setting the working current when stationary, and accurately match the temperature rise contribution of the composite loss during operation.

[0071] Compared to existing technologies, traditional methods typically use a fixed current threshold or a single loss model for temperature rise control, failing to differentiate between loss components at rest and in operation. This can lead to excessively high current settings in resting state, causing additional temperature rise, or insufficient current settings in operation, failing to offset the effects of iron losses. This solution, by identifying operating conditions and switching between loss models, dynamically matches current settings with heat source composition, fundamentally improving temperature rise control accuracy.

[0072] Through the above technical solution, this application can select a matching loss calculation model based on the actual operating state of the motor and accurately adjust the rated current setting value. In the static state, the current supply is reduced to reduce ineffective heating, and in the operating state, the current supply is increased to compensate for compound losses, thereby eliminating the temperature rise calculation error caused by different operating conditions and achieving precise temperature control across the entire operating range.

[0073] The present application further proposes that the method further includes: obtaining the I of the driver in real time through the PLC controller d and I q;Call the current distribution algorithm to redistribute I d and I q The reference value is set and the adjusted value is transmitted to the driver for execution.

[0074] Among them, PLC controller refers to programmable logic controller, which is implemented by industrial control computer with real-time data processing capability, and is used to directly read the internal current feedback signal of the motor driver. The current distribution algorithm refers to a dynamic optimization program based on the current vector, which is implemented by the method of solving the extreme value under the constraint conditions. By maintaining I 2 =I d 2 +I q 2 The driver execution link refers to the signal drive circuit of the power electronic device, which specifically uses PWM modulation technology to achieve a fast response to current commands.

[0075] Specifically, the PLC controller periodically reads the I2C data from the drive via the Modbus or EtherCAT communication protocol. d and I q Real-time measurement values are collected. When a sudden change in motor load is detected, the current distribution algorithm prioritizes adjusting the q-axis current to maintain torque demand while reducing the d-axis current to minimize iron losses. This adjusted reference value is transmitted to the drive's current loop controller via a digital signal interface, forming a fully closed-loop control system from parameter acquisition to command execution. During motor acceleration, the algorithm automatically increases the q-axis current weight to ensure dynamic response; during steady-state operation, it increases the d-axis current ratio to optimize magnetic field efficiency.

[0076] Compared with the existing technology, the traditional temperature compensation method requires additional deployment of temperature sensors and the establishment of temperature-error mapping models. However, this solution directly utilizes the current detection function built into the driver, eliminating the signal delay caused by sensor installation. d / I q The distribution strategy cannot adapt to load fluctuations. This solution dynamically balances the flux linkage and torque control requirements while maintaining a constant total current by adjusting the current distribution ratio in real time.

[0077] Through the above technical solution, this application achieves sensorless temperature rise suppression control, ensuring positioning accuracy while avoiding the hardware cost of an external temperature detection device. The dynamic adjustment mechanism of current distribution can quickly respond to load changes and reduce motor heating by optimizing current distribution. The closed-loop control architecture ensures accurate tracking of the current reference value, effectively suppressing mechanical deformation errors caused by temperature rise.

[0078] Example 2

[0079] like Figure 2 As shown, the present application further proposes a motor temperature control system, which is used to implement the motor temperature control method of the above embodiment 1, and includes a current setting module, a current calculation module, a filter module and a controller module.

[0080] Among them, the current setting module refers to a unit used to set the corresponding rated current according to the different operating states of the motor. It can be implemented by using a table lookup method or an operating condition identification algorithm. For example, the current setting value is switched by detecting the motor speed or load state. This module avoids control errors caused by a single current value by distinguishing the loss differences between the static and working states.

[0081] The current calculation module is a calculation unit that decomposes the rated current into d-axis and q-axis current components. It can be implemented by using a vector decomposition algorithm or a coordinate transformation formula. For example, based on the orthogonal decomposition principle, the current amplitude is allocated to I d and I q ,This module provides a dynamic reference for subsequent adjustments to ensure that the current vector amplitude is constant.

[0082] The filter module refers to a unit that suppresses high-frequency noise of the current reference value. Specifically, it can be implemented by a first-order low-pass filter. For example, the input signal is smoothed by a differential equation. This module eliminates signal noise interference and prevents control command oscillation.

[0083] The controller module is a dynamic adjustment module. d and I q The closed-loop control unit can be implemented using a proportional-integral algorithm. For example, the current component distribution is adjusted through error feedback. This module maintains a constant sum of the squares of the current amplitudes and indirectly suppresses temperature rise by controlling Joule loss.

[0084] Specifically, the current setting module outputs the corresponding rated current according to the motor working condition. For example, when the motor is stationary, the current value is set to take into account only the copper loss, and when the motor is working, the current value is set to include the iron loss. The current calculation module decomposes the rated current into I d and I q Reference value, ensured by orthogonal component distribution to meet I 2 =I d 2 +I q 2 The filter module filters the decomposed current reference value to eliminate high-frequency interference signals. For example, a PT1 filter with a time constant of 0.005 seconds is used to smooth the signal. The controller module adjusts I in real time through the PI algorithm. d and I q Component, dynamically adjust the ratio of the two when the load changes, for example, increase I when the motor accelerates q The component also reduces Id component, keeping the current amplitude constant, thereby controlling the Joule loss of the motor winding and stabilizing the temperature rise within the preset range.

[0085] Compared to existing technologies, traditional methods rely on temperature sensors to detect temperature rise and then apply compensation, which can lead to response lag and hardware cost issues. This system, however, directly regulates the heat source through closed-loop current control, eliminating the need for additional temperature detection devices and signal transmission delay. While existing technologies require the integration of sensors and compensation algorithms, increasing system complexity, this system achieves temperature rise suppression based on the existing motor control framework, eliminating the need for hardware modifications.

[0086] Through the above technical solution, this application eliminates the hardware dependence of traditional temperature compensation methods on sensors, directly controls the temperature rise source by adjusting the current component in real time, and achieves rapid response of temperature drift suppression; adopts current closed loop instead of temperature detection to avoid additional sensor costs and reduce system complexity; the dynamic adjustment mechanism based on the vector control framework can adapt to temperature rise changes under different working conditions and improve system control accuracy and reliability.

[0087] This application further proposes integrating the temperature control system into the PLC controller and establishing a communication connection with the motor driver to achieve temperature control by obtaining current parameters in real time and issuing control instructions.

[0088] The PLC controller, a programmable logic controller, is implemented using an industrial-grade embedded processor and real-time operating system. It executes control algorithms and interacts with external devices. This integration approach reuses existing control system hardware resources, eliminating the need for a separate independent temperature control module.

[0089] The communication link is the data channel between the PLC controller and the motor driver, using the CAN bus or EtherCAT protocol for bidirectional communication. This connection supports millisecond-level data transmission, ensuring real-time current parameter acquisition and control command issuance.

[0090] Specifically, the PLC controller continuously receives the actual I from the drive through the communication interface. d and I q The system calculates the current value, compares it with a reference value calculated based on Joule's law, and generates adjustment commands using the built-in PI control algorithm. The adjusted current reference value is transmitted back to the drive via the same communication link, forming a closed-loop control circuit. Because the current parameter is directly derived from the drive's internal acquisition unit, there is no need to rely on an external temperature sensor to detect temperature rise, eliminating delays in sensor signal conversion and transmission. Furthermore, by reusing the PLC controller's computing resources and communication interfaces, the system eliminates the need for a temperature acquisition module and its supporting circuitry, simplifying the hardware architecture.

[0091] Compared to existing technologies, traditional solutions require independent temperature sensors and signal processing circuits, indirectly calculating motor temperature rise by detecting ambient temperature, resulting in compensation lag and increased hardware costs. This solution, however, directly calculates the temperature rise effect based on current parameters and enables parameter interaction through real-time communication between the PLC and the drive. This avoids the physical delay of sensor signal acquisition while reducing hardware requirements and system complexity.

[0092] Through the above technical solution, this application achieves millisecond-level closed-loop control of current parameters, eliminating the response lag problem of traditional temperature compensation methods. By reusing existing controller resources and communication interfaces, the system reduces the hardware costs of temperature sensors, signal conditioning circuits, and other components. The integrated architecture avoids compatibility issues between new modules and existing systems, reducing the difficulty of equipment debugging and maintenance.

[0093] This application further proposes a technical solution in which the controller module combines the decoupling control of the d-axis current and the q-axis current with the rated current constant condition based on the field-oriented control framework to indirectly control the temperature.

[0094] Among them, the field-oriented control framework refers to a control architecture that decomposes the three-phase current of the motor into orthogonal d-axis and q-axis components through coordinate transformation. Specifically, space vector modulation technology can be used to achieve directional control of the current vector, thereby achieving independent regulation of the flux and torque. Among them, decoupling control refers to a separate control method in which the d-axis current is used to regulate the motor flux and the q-axis current is used to regulate the motor torque. Specifically, a current decoupling algorithm can be used to achieve independent closed-loop control of the two-axis currents, thereby avoiding mutual interference between the flux and torque. Among them, the rated current constant condition refers to the mathematical relationship that the sum of the squares of the d-axis and q-axis currents is constrained to be equal to the square of the rated current. Specifically, the total current can be maintained constant by real-time calculation and dynamic allocation of the two-axis current reference values, thereby limiting the total copper loss and iron loss during motor operation.

[0095] Specifically, this solution converts the three-phase stator current into d-axis and q-axis components in the rotating coordinate system under the field-oriented control framework, and independently adjusts the flux component and torque component through the decoupling control algorithm. During the control process, the total loss constraint value under different working conditions is calculated based on Joule's law and the iron loss model, and the constraint value is converted into the square value of the rated current. Subsequently, the distribution ratio of the d-axis and q-axis currents is dynamically adjusted so that the sum of the squares of the two-axis currents is always equal to the square value of the rated current. In this process, the adjustment range of the flux component and the torque component is constrained by the constant rated current, so that while the motor outputs the required torque, its total loss is limited to a predetermined range. The resulting temperature rise is indirectly controlled, and effective suppression of thermally induced deformation can be achieved without relying on external temperature sensors.

[0096] Compared with existing technologies, traditional methods require temperature sensors to detect temperature rise before implementing compensation control, which results in detection lag and additional hardware costs. This solution dynamically allocates the current vector directly through a field-oriented control framework, embedding temperature rise constraints during control command generation. This enables feedforward suppression of temperature drift without the need for additional temperature detection devices. This solution transforms temperature control into a real-time optimization problem for the current vector. Through the dual effects of decoupling control and current constraints, it achieves temperature rise control while ensuring motor output performance.

[0097] Through the above-mentioned technical solution, this application can eliminate the response lag problem existing in traditional temperature compensation methods and achieve instant control of temperature rise through real-time dynamic adjustment of the current vector. At the same time, this solution does not require the addition of temperature sensors and their supporting circuits, effectively reducing system hardware cost and integration complexity. Furthermore, the decoupling control mechanism based on the field-oriented control framework can be seamlessly integrated with existing motor drive systems, avoiding disruptive modifications to the control system architecture.

[0098] A motor temperature control system of this embodiment is used to implement the aforementioned motor temperature control method. Therefore, the specific implementation of the motor temperature control system can be found in the embodiment part of the motor temperature control method above. In order to avoid redundancy, it will not be repeated here.

[0099] Example 3

[0100] like Figure 3 As shown, the present application further proposes a motor temperature control device, including a motor driver and a PLC controller. The motor driver is used to output a PWM signal to control the operation of the motor; the PLC controller is used to execute the motor temperature control method and obtain I in real time. d and I q and reallocate the I d and I q transmitted to the motor driver.

[0101] The motor driver, a power electronic device that converts control signals into motor drive signals, can be implemented using a three-phase full-bridge inverter circuit. This circuit controls the motor's current output by adjusting the PWM duty cycle. A PLC controller, a programmable logic controller, can be implemented using an embedded processor equipped with a real-time operating system. It executes current parameter calculation and distribution algorithms, indirectly controlling the motor's temperature rise. The communication interface, a data exchange channel, can be implemented using the CAN bus or EtherCAT protocol to ensure real-time transmission of current parameters and synchronized instructions.

[0102] Specifically, the device achieves non-sensing temperature control through the collaborative design of hardware architecture and software control. The motor driver generates PWM drive signals that directly act on the power conversion link of the motor to ensure precise control of the current; the PLC controller processes I through the current distribution algorithm. d and I q Parameters, eliminating the need for temperature sensor signal acquisition; the communication interface realizes closed-loop data transmission between the controller and the driver. During operation, the PLC controller obtains the I feedback of the driver in real time. d and I q The actual value is calculated by combining Joule's law to calculate the mapping relationship between current and temperature rise, and the current reference value is dynamically adjusted and sent to the driver through the communication interface for execution to keep the rated current constant.

[0103] Compared with existing technologies, traditional methods rely on external temperature sensors to detect ambient temperature changes, and require the configuration of signal processing circuits and the integration of compensation algorithms, resulting in high hardware costs and delayed response. d and I q The current parameters realize temperature rise control, eliminating the sensor signal acquisition and conversion links. The current adjustment instructions can complete closed-loop transmission and execution within milliseconds, while reducing the use of additional circuit components.

[0104] Through the above technical solution, this application achieves real-time control of motor temperature rise without the need for external temperature sensors, avoiding compensation delays caused by sensor response lag, reducing hardware configuration costs, and simplifying system integration complexity. The closed-loop regulation mechanism of current parameters acts directly on the motor drive, ensuring rapid response and precise execution of temperature control commands, effectively suppressing positioning errors caused by temperature drift.

[0105] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0106] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0107] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0108] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A motor temperature control method, characterized in that: include: Set the corresponding rated current based on different motor operating conditions; Based on the set rated current I, the motor's I is calculated in real time d and I q Reference value, where I d is the d-axis current, I q is the q-axis current; Through the low-pass filter d and I q The reference value is filtered to suppress high-frequency noise; Use a PI controller to dynamically adjust I d and I q , so that the rated current meets I 2 =I d 2 +I q 2 And keep it constant, thereby indirectly controlling the temperature rise of the motor and suppressing the positioning error caused by temperature changes.

2. The motor temperature control method according to claim 1, characterized in that: Dynamic Adjustment I d and I q The steps include: When the motor is stationary or the load changes, the current decoupling control technology is used to coordinate I d and I q The distribution of I d Used to control the motor flux, I q Used to control the motor torque and ensure the rated current is constant; Combined with PI controller d and I q Perform closed-loop adjustments to respond to real-time operating conditions.

3. The motor temperature control method according to claim 1, characterized in that: The low-pass filter is a PT1 filter, and its differential equation is: y(n)=α·x(n)+(1-α)·y(n-1); Among them, y(n) is the filter output value at the current moment, y(n-1) is the filter output value at the previous moment, x(n) is the input signal value at the current moment, and the filter coefficient α is determined by the sampling period T s and the filtering time constant τ, satisfying And the value range of τ is 0.001-0.01 seconds.

4. The motor temperature control method according to claim 1, characterized in that: The rated current setting based on different motor operating conditions includes: When the motor is stationary, only the copper loss is considered and I=I0 is set, where I0 is the stationary current; When the motor is in working condition, taking into account both copper loss and iron loss, set I = I n , I n is the rated current.

5. The motor temperature control method according to claim 1, characterized in that: The method further comprises: Get the driver's I in real time through the PLC controller d and I q ; The current distribution algorithm is called to reallocate the reference values of Id and Iq, and the adjusted values are transmitted to the driver for execution.

6. A motor temperature control system, characterized in that: The system is used to implement the motor temperature control method according to any one of claims 1 to 5, specifically comprising: Current setting module, used to set the corresponding rated current based on different motor operating conditions; The current calculation module is used to calculate the motor's I in real time based on the set rated current I d and I q Reference value, where I d is the d-axis current, I q is the q-axis current; The filter module is used to filter I d and I q The reference value is filtered to suppress high-frequency noise; Controller module, used to dynamically adjust the I d and I q , so that the rated current meets I 2 =I d 2 +I q 2 And keep it constant, thereby indirectly controlling the temperature rise of the motor and suppressing the positioning error caused by temperature changes.

7. The motor temperature control system according to claim 6, characterized in that: The system is integrated into the PLC controller and communicates with the motor driver to achieve I d and I q Real-time acquisition and instruction issuance.

8. The motor temperature control system according to claim 6, characterized in that: The controller module is based on the field-oriented control framework. d and I q The decoupling control is combined with the constant rated current condition to achieve temperature control.

9. A motor temperature control device, characterized in that: include: Motor driver, used to output PWM signal to control the operation of the motor; A PLC controller is used to execute the motor temperature control method according to any one of claims 1 to 5, and obtain I d and I q and reallocate the I d and I q transmitted to the motor driver.

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