A cooperative control method and system for permanent magnet assisted synchronous reluctance motors

Abstract

A collaborative control method and system for a permanent magnet assisted synchronous reluctance motor is disclosed. In this method, the permanent magnet torque component and the reluctance torque component are calculated. Within a single preset control cycle, the current vector angle is adjusted to increase the permanent magnet torque component and decrease the reluctance torque component, forming a torque component unbalanced state. Under startup conditions, starting from the torque component unbalanced state, the current vector angle is gradually increased according to a preset step size to decrease the permanent magnet torque component and increase the reluctance torque component, and the total system loss is calculated. When it is determined that the total system loss reaches its minimum value within a preset time period, the current vector angle corresponding to the minimum total system loss is taken as the target current vector angle. Based on the target current vector angle, d-axis current commands and q-axis current commands are calculated and output to the current loop controller. This application aims to improve the torque response speed and energy utilization efficiency of a permanent magnet assisted synchronous reluctance motor in a water pump or fan under startup conditions.

Description

Technical Field

[0001] This application belongs to the field of permanent magnet assisted synchronous reluctance motor control, and particularly relates to a cooperative control method and system for permanent magnet assisted synchronous reluctance motors. Background Technology

[0002] Permanent magnet assisted synchronous reluctance motors (PMRMs), as a new type of motor that combines the high power density of PMRMs with the low cost of synchronous reluctance motors, are widely used in fields such as water pump drives and fan drives. However, because PMRMs simultaneously have two torque components—permanent magnet torque and reluctance torque—and there is a complex coupling relationship between them, traditional single control strategies are difficult to achieve the optimal operating state of the motor. Especially under varying operating conditions, the motor efficiency and dynamic response performance often fall short of ideal levels.

[0003] In related technologies, the mechanical angular velocity error can be established first. Based on the dynamic equations of the PMSM, an adaptive controller is designed to link the mechanical angular velocity in the speed loop with the stator current. Then, the lead angle corresponding to the traditional operating point of MTPA is determined using the extreme value principle. The stator current is input to the basic module of MTPA control so that the stator current is minimized when the electromagnetic torque is maximized, thereby reducing copper losses. Next, the dq axis voltage and current are detected to obtain the output mechanical power. The relationship between this power and the high-frequency change angle is determined, and the high-frequency component is obtained using a bandpass filter. By controlling the high-frequency component to zero, a new MTPA control is achieved, and the current angle corresponding to the new MTPA operating point is obtained. Finally, the output mechanical power and the change in the current vector are input into a recursive probabilistic wavelet fuzzy neural network to output the high-frequency change angle. Based on the current angle corresponding to the new MTPA operating point, the closed-loop optimization of the control system is achieved.

[0004] In applications involving water pumps or fans, these motors need to maintain stable output performance under various operating conditions. Since the determination of the MTPA (Medium-to-Actual Motor Position) operating point relies on high-frequency mechanical power feedback, a significant convergence time is required to re-find the optimal current angle when the pump or fan suddenly starts, causing a sharp increase in load torque. During this period, the ratio of permanent magnet torque to reluctance torque components deviates from the optimal state, thus reducing the torque response speed and energy utilization efficiency of the permanent magnet assisted synchronous reluctance motor during pump or fan startup. Summary of the Invention

[0005] This application provides a cooperative control method and system for permanent magnet assisted synchronous reluctance motors, which can improve the torque response speed and energy utilization efficiency of permanent magnet assisted synchronous reluctance motors in the starting condition of water pumps or fans.

[0006] In the first aspect, this application provides a cooperative control method for a permanent magnet assisted synchronous reluctance motor, which calculates the permanent magnet torque component and the reluctance torque component based on the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor detected in real time.

[0007] If the change in the target torque within a preset time is greater than a preset threshold, it is determined that the permanent magnet assisted synchronous reluctance motor is in the starting condition.

[0008] Within a single preset control cycle, the current vector angle is adjusted to increase the permanent magnet torque component and decrease the reluctance torque component, forming a torque component unbalanced state. The torque component unbalanced state is the state in which the permanent magnet torque component and the reluctance torque component deviate from the operating point of the maximum torque current ratio MTPA.

[0009] Under startup conditions, starting from the unbalanced state of the torque component, the current vector angle is gradually increased according to a preset step size to reduce the permanent magnet torque component and increase the reluctance torque component, and the total system loss is calculated after each preset step size adjustment.

[0010] When it is determined that the total system loss reaches its minimum value within a preset time period, the current vector angle corresponding to the minimum total system loss is taken as the target current vector angle.

[0011] The d-axis current command and q-axis current command are calculated based on the target current vector angle, and then output to the current loop controller.

[0012] By adopting the above technical solution, when the change in target torque within a preset time period exceeds a preset threshold, the system can accurately identify the occurrence of the startup condition, reducing the lag and inaccuracy in condition identification. During startup, the system actively creates a torque imbalance state by rapidly adjusting the current vector angle within a single preset control cycle to increase the permanent magnet torque component and decrease the reluctance torque component. This state deviates from the maximum torque-to-current ratio (MTPA) operating point, providing ample adjustment space for subsequent optimization. Subsequently, the system gradually increases the current vector angle according to preset step sizes, decreasing the permanent magnet torque component and increasing the reluctance torque component. After each preset step adjustment, the total system loss is calculated, and the minimum point of the total system loss is found through systematic loss assessment. When the minimum of the total system loss is determined within a preset time period, the corresponding current vector angle is determined as the target current vector angle, achieving precise convergence from the imbalance state to the optimal efficiency state. The d-axis current command and q-axis current command calculated based on the target current vector angle can control the operation of the current loop controller, ensuring that the motor can meet the torque requirements and achieve the lowest system loss under the starting condition, thereby improving the torque response speed and energy utilization efficiency of the permanent magnet assisted synchronous reluctance motor of the water pump or fan under the starting condition.

[0013] In conjunction with some embodiments of the first aspect, in some embodiments, the permanent magnet torque component and the reluctance torque component are calculated based on the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor detected in real time, specifically including:

[0014] Receive the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor sent by the sensor;

[0015] The d-axis current and q-axis current are obtained by coordinate transformation based on stator current and rotor position;

[0016] The product of the permanent magnet flux linkage and the q-axis current is determined as the permanent magnet torque component.

[0017] The difference between the d-axis inductance and the q-axis inductance is multiplied by the product of the d-axis current and the q-axis current to obtain the reluctance torque component.

[0018] By adopting the above technical solution, and by receiving the stator current and rotor position information of the permanent magnet assisted synchronous reluctance motor sent by the sensor, a torque component calculation basis based on real-time detection data is established, which improves the accuracy and timeliness of the calculation results. By calculating the torque components generated by two different physical mechanisms respectively, the system can independently evaluate and optimize the contribution of each torque component, so that the control system can flexibly adjust the ratio of the two torque components according to different operating conditions, thereby achieving higher control flexibility and efficiency optimization space.

[0019] In conjunction with some embodiments of the first aspect, in some embodiments, the total system loss is calculated after each preset step size adjustment, specifically including:

[0020] After each preset step size adjustment, the corresponding d-axis current and q-axis current are calculated based on the adjusted current vector angle;

[0021] The stator winding copper loss is calculated using the formula for calculating stator winding copper loss, as well as the d-axis and q-axis currents. The formula for calculating stator winding copper loss is as follows: ;

[0022] For stator winding copper loss, For stator resistance, For d-axis current, This is the q-axis current;

[0023] The core loss rate is calculated using the core loss calculation formula, which is: ;

[0024] For core loss, It is a hysteresis loss system. For power supply frequency, For maximum magnetic flux density, For eddy current loss system;

[0025] The total system loss is obtained by adding the stator winding copper loss and the core loss.

[0026] By adopting the above technical solution, the corresponding d-axis current and q-axis current are calculated based on the adjusted current vector angle after each preset step size adjustment, ensuring the synchronization and consistency between loss calculation and actual control parameters, and reducing the loss assessment deviation caused by parameter mismatch. The stator winding copper loss calculation formula is based on the basic principle of Joule's law and can accurately reflect the resistive loss generated by the current in the stator winding. The core loss calculation formula comprehensively covers the main mechanisms of core loss. The method of adding the stator winding copper loss and the core loss to obtain the total system loss covers the main loss sources in the operation of permanent magnet assisted synchronous reluctance motors, providing a complete calculation framework for the comprehensive assessment of system losses.

[0027] In conjunction with some embodiments of the first aspect, in some embodiments, after adjusting the current vector angle within a single preset control cycle to increase the permanent magnet torque component and decrease the reluctance torque component, thus forming a torque component unbalanced state, the method further includes:

[0028] Real-time detection of the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current;

[0029] When the first difference or the second difference is less than the preset safety margin, calculate the first proportionality coefficient and the second proportionality coefficient of the permanent magnet torque component and the reluctance torque component in the total torque under the current vector angle.

[0030] Based on the first proportional coefficient, the second proportional coefficient, and the current torque demand, a target proportional coefficient is determined by numerical solution method to ensure that both the first difference and the second difference are not less than the preset safety margin.

[0031] Based on the target proportional coefficient and the current torque requirement, calculate the corresponding d-axis current target value and q-axis current target value according to the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component;

[0032] Convert the d-axis current target value and the q-axis current target value into the adjusted current vector angle;

[0033] Starting from the adjusted current vector angle, repeat the step of gradually increasing the current vector angle according to the preset step size.

[0034] By adopting the above technical solution, and by real-time detection of the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current, the damage caused by current over-limit during the optimization process to the motor and control system is reduced. When either the first or second difference is less than the preset safety margin, the system can promptly identify potential current over-limit risks. Based on the first proportional coefficient, the second proportional coefficient, and the current torque demand, a target proportional coefficient is determined through numerical solution methods to ensure that both the first and second differences are not less than the preset safety margin. This process reallocates the torque component proportions while ensuring current safety, achieving optimized torque allocation under safety constraints. According to the target proportional coefficient and the current torque demand, the corresponding target values ​​of the d-axis current and q-axis current are calculated according to the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component, ensuring that the reallocated torque components can meet the total torque demand. The target values ​​of the d-axis current and q-axis current are converted into adjusted current vector angles. Starting from these adjusted current vector angles, the process of gradually increasing the current vector angle according to a preset step size is re-executed. This enables the safe restart and continuation of the optimization process, maintains the continuity and effectiveness of loss optimization, and improves the reliability and practicality of the control system.

[0035] In conjunction with some embodiments of the first aspect, in some embodiments, the target values ​​of the d-axis current and the q-axis current are converted into adjusted current vector angles, specifically including:

[0036] Calculate the current vector magnitude based on the target values ​​of the d-axis and q-axis currents;

[0037] Based on the target values ​​of the d-axis current, the target value of the q-axis current, and the magnitude of the current vector, the adjusted current vector angle is calculated using the arctangent function. The adjusted current vector angle satisfies the following conditions: the target value of the d-axis current is equal to the product of the magnitude of the current vector and the cosine of the adjusted current vector angle; and the target value of the q-axis current is equal to the product of the magnitude of the current vector and the sine of the adjusted current vector angle.

[0038] By employing the above technical solution, the total current required for motor operation can be accurately determined based on the calculation of the current vector amplitude. Through parameter transformation, the motor can achieve optimal current distribution while maintaining the desired torque output, thereby improving the motor's operating efficiency and control accuracy.

[0039] In conjunction with some embodiments of the first aspect, in some embodiments, after outputting the d-axis current command and the q-axis current command to the current loop controller, the method further includes:

[0040] The difference between the current loss value and the initial reference loss value of the permanent magnet assisted synchronous reluctance motor is detected in real time to obtain the amount of motor loss reduction;

[0041] Detect the power increase of the DC / DC converter and charger that share a power supply with the permanent magnet assisted synchronous reluctance motor;

[0042] When the reduction in motor losses is greater than a preset redistribution threshold, and the power increase of at least one of the DC / DC converter and charger is greater than a preset transfer threshold, calculate the total power increase of the DC / DC converter and charger.

[0043] When the increase in total power is greater than the decrease in motor losses, it is determined that an increase in global energy consumption has occurred.

[0044] Obtain the output voltage adjustment range of the DC / DC converter and the charging current adjustment range of the charger;

[0045] While keeping the target current vector angle constant, adjust the output voltage of the DC / DC converter and the charging current of the charger so that the increase in total power is not greater than the reduction in motor losses.

[0046] The adjusted output voltage command is sent to the DC / DC converter, and the adjusted charging current command is sent to the charger.

[0047] By adopting the above technical solution and monitoring the relationship between the reduction in motor losses and the increase in power of the DC / DC converter and charger in real time, the system can promptly detect potential global energy consumption deterioration caused by local optimization, avoiding the technical flaw of simply pursuing motor efficiency improvement while neglecting the overall vehicle energy consumption balance. When the energy-saving effect of reduced motor losses is offset by the increased power of other devices, the system can automatically identify and activate the global energy consumption balance adjustment mechanism. By setting redistribution and transfer thresholds, the system can trigger coordinated control only when the benefits of improved motor efficiency are sufficiently significant, avoiding system stability issues that may arise from frequent adjustments. By adjusting the output voltage of the DC / DC converter and the charging current of the charger while keeping the target current vector angle constant, the optimal operating state of the motor is maintained. Global energy consumption rebalancing is achieved through parameter optimization of peripheral devices, ensuring that the energy savings from improved motor efficiency are converted into a reduction in overall vehicle energy consumption, rather than being consumed by the increased energy consumption of other devices. This improves the overall efficiency of the power system and enhances the endurance and energy utilization economy of the water pump or fan under startup conditions.

[0048] In conjunction with some embodiments of the first aspect, in some embodiments, adjusting the output voltage of the DC / DC converter and the charging current of the charger specifically includes:

[0049] Acquire power loss data of DC / DC converters at different output voltages and power loss data of chargers at different charging currents;

[0050] Within the output voltage adjustment range, the output voltage of the DC / DC converter is increased in preset voltage steps, and the corresponding power loss value is recorded; within the charging current adjustment range, the charging current of the charger is decreased in preset current steps, and the corresponding power loss value is recorded.

[0051] Calculate the total power loss of the DC / DC converter and charger under each voltage step and each current step combination;

[0052] Select the target combination of voltage and current step sizes that minimizes the total power loss and is not greater than the reduction in motor loss.

[0053] The output voltage corresponding to the target combination is used as the adjusted output voltage command, and the charging current corresponding to the selected target combination is used as the adjusted charging current command.

[0054] By adopting the above technical solution, and employing a strategy of increasing the DC / DC converter output voltage with preset voltage steps and decreasing the charger charging current with preset current steps, the system can systematically explore the optimal combination of operating parameters within their respective adjustment ranges, avoiding the local optima problem that may be caused by random search. By calculating the total power loss under each parameter combination, the system can quantitatively evaluate the energy consumption effect of different adjustment strategies, ensuring that the selected parameter combination can achieve energy consumption reduction. Through parameter optimization and matching strategies, the power supply system can achieve the lowest overall power loss while meeting the normal operating requirements of each device, thereby maximizing the energy-saving effect brought about by improved motor efficiency and improving the overall performance of the energy management system.

[0055] Secondly, embodiments of this application provide a cooperative control system for a permanent magnet assisted synchronous reluctance motor. The cooperative control system for the permanent magnet assisted synchronous reluctance motor includes: one or more processors and a memory; the memory is coupled to one or more processors, and the memory is used to store computer program code, the computer program code including computer instructions, and the one or more processors call the computer instructions to cause the system to perform the method described in the first aspect and any possible implementation of the first aspect.

[0056] Thirdly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a system, cause the system to perform the method described in the first aspect and any possible implementation thereof.

[0057] Fourthly, embodiments of this application provide a computer program product that, when run on a system, causes the system to execute the method described in any possible implementation of the first aspect.

[0058] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0059] 1. This application provides a cooperative control method for a permanent magnet assisted synchronous reluctance motor. When the change in target torque within a preset time period exceeds a preset threshold, the system can accurately identify the occurrence of the starting condition, reducing the lag and inaccuracy in condition identification. During the starting condition, the system actively creates a torque imbalance state by rapidly adjusting the current vector angle within a single preset control cycle to increase the permanent magnet torque component and decrease the reluctance torque component. This state deviates from the maximum torque-to-current ratio (MTPA) operating point, providing sufficient adjustment space for subsequent optimization. Subsequently, the system gradually increases the current vector angle according to preset step sizes, decreasing the permanent magnet torque component and increasing the reluctance torque component. After each preset step adjustment, the total system loss is calculated, and the minimum point of the total system loss is found through systematic loss evaluation. When the minimum value of the total system loss is determined within a preset time period, the corresponding current vector angle is determined as the target current vector angle, achieving precise convergence from the imbalance state to the optimal efficiency state. The d-axis current command and q-axis current command calculated based on the target current vector angle can control the operation of the current loop controller, ensuring that the motor can meet the torque requirements and achieve the lowest system loss under the starting condition, thereby improving the torque response speed and energy utilization efficiency of the permanent magnet assisted synchronous reluctance motor of the water pump or fan under the starting condition.

[0060] 2. This application provides a cooperative control method for a permanent magnet assisted synchronous reluctance motor. By real-time detection of the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current, the damage caused by current over-limit during the optimization process to the motor and control system is reduced. When either the first or second difference is less than a preset safety margin, the system can promptly identify potential current over-limit risks. Based on the first proportional coefficient, the second proportional coefficient, and the current torque demand, a target proportional coefficient is determined through numerical solution methods to ensure that both the first and second differences are not less than the preset safety margin. This process reallocates the torque component proportions while ensuring current safety, achieving optimized torque allocation under safety constraints. According to the target proportional coefficient and the current torque demand, the corresponding target values ​​of the d-axis current and q-axis current are calculated according to the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component, ensuring that the reallocated torque components can meet the total torque demand. The target values ​​of the d-axis current and q-axis current are converted into adjusted current vector angles. Starting from these adjusted current vector angles, the process of gradually increasing the current vector angle according to a preset step size is re-executed. This enables the safe restart and continuation of the optimization process, maintains the continuity and effectiveness of loss optimization, and improves the reliability and practicality of the control system.

[0061] 3. This application provides a cooperative control method for permanent magnet assisted synchronous reluctance motors. By monitoring the relationship between the reduction in motor losses and the increase in power of the DC / DC converter and charger in real time, it can promptly detect global energy consumption deterioration that may be caused by local optimization, avoiding the technical defects of simply pursuing motor efficiency improvement while ignoring energy consumption balance. When the energy-saving effect of reduced motor losses is offset by the increase in power of other devices, the system can automatically identify and activate the global energy consumption balance adjustment mechanism to ensure optimal energy management. By setting redistribution thresholds and transfer thresholds, the system can trigger coordinated control only when the benefits of improved motor efficiency are sufficiently significant, avoiding system stability problems that may be caused by frequent adjustments. By adjusting the output voltage of the DC / DC converter and the charging current of the charger while keeping the target current vector angle constant, the optimal operating state of the motor is maintained. Global energy consumption rebalancing is achieved through parameter optimization of peripheral devices, so that the energy savings brought by the improvement in motor efficiency can be converted into energy consumption reduction, rather than being consumed by the increase in energy consumption of other devices, thereby maximizing the overall efficiency of the power system. Attached Figure Description

[0062] Figure 1 This is a flowchart illustrating a collaborative control method for a permanent magnet assisted synchronous reluctance motor in an embodiment of this application.

[0063] Figure 2 This is another flowchart illustrating a collaborative control method for a permanent magnet assisted synchronous reluctance motor in an embodiment of this application.

[0064] Figure 3 This is a schematic diagram of the physical device structure of a cooperative control system for a permanent magnet assisted synchronous reluctance motor provided in an embodiment of this application. Detailed Implementation

[0065] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0066] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0067] The following example is used in conjunction with Figure 1 The present application describes a cooperative control method for a permanent magnet assisted synchronous reluctance motor in its embodiments:

[0068] Please see Figure 1 This is a flowchart illustrating a collaborative control method for a permanent magnet assisted synchronous reluctance motor in an embodiment of this application.

[0069] S101. Calculate the permanent magnet torque component and the reluctance torque component based on the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor detected in real time.

[0070] The system calculates the permanent magnet torque component and the reluctance torque component based on the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor detected in real time. Specifically, it includes: receiving the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor sent by the sensor; performing coordinate transformation based on the stator current and rotor position to obtain the d-axis current and q-axis current; determining the permanent magnet torque component by multiplying the permanent magnet flux linkage and the q-axis current; and multiplying the difference between the d-axis inductance and the q-axis inductance by the product of the d-axis current and the q-axis current to obtain the reluctance torque component.

[0071] The system calculates the permanent magnet torque component and the reluctance torque component based on the real-time detected stator current and rotor position of the permanent magnet assisted synchronous reluctance motor. Specifically, the system receives stator current and rotor position signals from sensors, reflecting the real-time operating status of the permanent magnet assisted synchronous reluctance motor. Then, based on the acquired stator current and rotor position signals, the system performs coordinate transformation, converting the stator current in the three-phase stationary coordinate system to the two-phase rotating coordinate system, obtaining the d-axis current component and the q-axis current component. Next, the system multiplies the flux linkage value of the permanent magnet in the dq coordinate system with the q-axis current component, and determines the permanent magnet torque component by the product. The system also obtains the d-axis inductance value and the q-axis inductance value according to the structural characteristics of the permanent magnet assisted synchronous reluctance motor, and multiplies the difference between the two with the product of the d-axis current component and the q-axis current component; the resulting product is the reluctance torque component. It should be noted that the calculation of the permanent magnet torque component only requires the q-axis current component, while the calculation of the reluctance torque component requires both the d-axis current component and the q-axis current component, but the specific calculation method is not limited here.

[0072] One possible approach to calculating the permanent magnet torque component and the reluctance torque component is as follows: First, the system establishes a mathematical model of the permanent magnet assisted synchronous reluctance motor based on its physical parameters, such as permanent magnet flux linkage, stator resistance, and inductance. After obtaining stator current and rotor position feedback signals, the system substitutes these feedback quantities into the current and torque equations in the mathematical model. Through formula simplification, variable substitution, and other mathematical methods, the system ultimately derives the expressions for the permanent magnet torque component and the reluctance torque component, thus completing the torque component calculation. Another approach is to pre-analyze the permanent magnet assisted synchronous reluctance motor using finite element analysis and establish torque lookup tables for different current magnitudes and rotor positions. During actual control, the system uses the detected stator current and rotor position as lookup table indexes to directly retrieve the permanent magnet torque component and reluctance torque component for the corresponding operating condition, thus eliminating the need for complex real-time mathematical calculations.

[0073] During actual operation, the stator current and rotor position of a permanent magnet assisted synchronous reluctance motor may be affected by measurement noise and external interference, leading to distorted feedback signals and affecting the accuracy of torque component calculation. To address this issue, the system can filter the feedback signal after acquisition to remove high-frequency interference components. Furthermore, the system can employ an adaptive control algorithm to dynamically correct the calculation formulas or lookup tables for the permanent magnet torque component and the reluctance torque component based on the motor's actual output torque, improving the dynamic accuracy of torque component calculation and enhancing the system's adaptability to parameter changes.

[0074] S102. If the change in the target torque within a preset time is greater than a preset threshold, it is determined that the permanent magnet assisted synchronous reluctance motor is in the starting condition.

[0075] The system monitors the target torque of the permanent magnet assisted synchronous reluctance motor in real time and calculates the change in target torque over a preset time period. When the detected change in target torque exceeds a preset threshold, the system determines that the motor is currently in startup mode. It should be noted that the target torque can originate from commands from a higher-level control system; this is not limited here. The preset threshold can be reasonably set based on factors such as the motor's rated torque.

[0076] One possible method for obtaining the target torque is as follows: the system calculates the target torque that the motor needs to output using a formula based on instructions sent by the controller. After obtaining the target torque, the system compares it with the target torque from a preset time period ago and calculates whether the change exceeds a preset threshold. Another approach is for the system to monitor the actual output torque of the permanent magnet assisted synchronous reluctance motor in real time and extract its changing trend. When the rate of change of the actual torque within a preset time period exceeds a preset rate threshold, the system can also determine that it is in a starting condition. This method based on actual torque changes can avoid misjudgments caused by sudden changes in the target torque.

[0077] It should be noted that there is no strict execution sequence for steps S101 and S102; that is, the two steps can be executed simultaneously or sequentially, and no restriction is imposed here.

[0078] S103. Within a single preset control cycle, the current vector angle is adjusted to increase the permanent magnet torque component and decrease the reluctance torque component, thus forming a torque component unbalanced state.

[0079] Within a single preset control cycle, the system adjusts the current vector angle to increase the permanent magnet torque component and decrease the reluctance torque component, forming a torque component unbalanced state. The torque component unbalanced state is the state in which the permanent magnet torque component and the reluctance torque component deviate from the operating point of the maximum torque-current ratio MTPA.

[0080] Once the system determines that the permanent magnet assisted synchronous reluctance motor has entered the starting condition, it will rapidly adjust the current vector angle within a single preset control cycle, increasing the permanent magnet torque component and decreasing the reluctance torque component, thus actively creating an unbalanced torque state. This preset control cycle can be reasonably set according to the system's control frequency and the motor's dynamic response characteristics, typically in the millisecond range, and is not strictly limited here. In the unbalanced state, the ratio of permanent magnet torque to reluctance torque deviates from the optimal ratio point under maximum torque-to-current ratio (MTPA) control, providing sufficient adjustment margin for subsequent optimized control of system losses.

[0081] The current vector angle can be adjusted by changing the given d-axis and q-axis current commands. One possible adjustment method is that after detecting the start-up condition, the system immediately increases the q-axis current command by a certain magnitude while simultaneously decreasing the d-axis current command by the same magnitude, thereby increasing the current vector angle while keeping the magnitude of the combined current vector constant. This adjustment method has a fast response speed and can quickly establish the unbalanced torque component within a single control cycle. Another implementation method is that the system pre-calculates a series of d-axis and q-axis current commands under a series of current vector angles based on the MTPA curve and motor parameters, forming a current vector angle lookup table for the start-up condition. After entering the start-up condition, the system directly selects the preset current vector angle from the lookup table and sends the corresponding d-axis and q-axis current commands without real-time calculation.

[0082] In practical applications, due to factors such as changes in motor parameters and measurement errors, directly adjusting the current vector angle may be insufficient to accurately control the torque component. To improve adjustment accuracy, a closed-loop feedback control mechanism can be introduced. Specifically, the system can measure the actual values ​​of the permanent magnet torque component and the reluctance torque component in real time and compare them with the expected values ​​to calculate the torque component error. Then, based on the torque component error and preset controller parameters (such as proportional coefficient and integral coefficient), the system calculates the adjustment amount of the current vector angle and performs closed-loop correction on the current vector angle. In this way, precise control of the torque component can be achieved, ensuring that the expected torque component imbalance state is formed in each control cycle.

[0083] Furthermore, under unbalanced torque components, the motor's loss characteristics may change, leading to a sharp increase or discontinuous changes in losses at certain operating points. To prevent the control process from getting stuck at these abnormal points, the system can introduce loss constraints. Specifically, the system can estimate the total system loss at different current vector angles in real time and compare it with a preset upper limit for losses. If the total system loss exceeds the upper limit during adjustment, the current adjustment step is stopped, and the process moves to the next current vector angle. In this way, it can be ensured that the total system loss remains within an acceptable range throughout the entire adjustment process, avoiding abnormal loss points. Simultaneously, the system can also record the current vector angles where abnormal losses occurred during historical adjustments, skipping these angles in subsequent adjustments, further improving the stability and reliability of the control.

[0084] S104. Under the starting condition, starting from the unbalanced state of the torque component, the current vector angle is gradually increased according to the preset step size to reduce the permanent magnet torque component and increase the reluctance torque component, and the total system loss is calculated after each preset step size adjustment.

[0085] Starting from the unbalanced torque component state during startup, the system gradually increases the current vector angle according to a preset step size, causing the permanent magnet torque component to decrease and the reluctance torque component to increase. After each preset step size adjustment, the total system loss is calculated. Specifically, the calculation of the total system loss after each preset step size adjustment includes:

[0086] After each preset step size adjustment, the corresponding d-axis current and q-axis current are calculated based on the adjusted current vector angle;

[0087] The stator winding copper loss is calculated using the formula for calculating stator winding copper loss, as well as the d-axis and q-axis currents. The formula for calculating stator winding copper loss is as follows: ;

[0088] For stator winding copper loss, For stator resistance, For d-axis current, This is the q-axis current;

[0089] The core loss rate is calculated using the core loss calculation formula, which is: ;

[0090] For core loss, It is a hysteresis loss system. For power supply frequency, For maximum magnetic flux density, For eddy current loss system;

[0091] The total system loss is obtained by adding the stator winding copper loss and the core loss.

[0092] During startup, the system begins in a torque component unbalanced state and gradually increases the current vector angle according to a preset step size. Increasing the current vector angle reduces the permanent magnet torque component and increases the reluctance torque component. During this process, the system calculates the total system loss after each preset step size adjustment. The total system loss includes stator winding copper loss and core loss. Stator winding copper loss can be calculated using the stator winding copper loss calculation formula, along with the d-axis and q-axis currents. Core loss can be calculated using the core loss calculation formula. Finally, the stator winding copper loss and core loss are added together to obtain the total system loss. It should be noted that the preset step size can be set according to actual conditions. The step size affects the adjustment accuracy and speed, but the specific value is not limited here. Similarly, the parameter values ​​in the stator winding copper loss calculation formula and the core loss calculation formula can also be set according to actual conditions when calculating the total system loss; these are not limited here.

[0093] The process of gradually increasing the current vector angle and calculating the total system loss in this step can be achieved in at least the following two ways:

[0094] Set a fixed step size, for example, increasing by 1° each time, starting from the initial current vector angle and increasing by 1° each time, until the preset maximum current vector angle is reached. After each increase in the current vector angle, calculate the corresponding d-axis current and q-axis current based on the adjusted current vector angle, then calculate the stator winding copper loss and core loss respectively, and finally add them together to obtain the total system loss.

[0095] Set a dynamic step size. The initial step size can be set relatively large, such as 5°. As the current vector angle increases, gradually decrease the step size, for example, to 1°. This allows for rapid approach to the optimum in the early stages, followed by smaller step adjustments in the later stages to improve accuracy. Similarly, after each increase in the current vector angle, the corresponding total system loss needs to be calculated.

[0096] S105. When it is determined that the total system loss reaches its minimum value within a preset time period, the current vector angle corresponding to the minimum total system loss is taken as the target current vector angle.

[0097] As the system gradually increases the current vector angle, it calculates the total system loss after each preset step adjustment. By monitoring and comparing the total system loss, it can determine whether the total system loss reaches its minimum value within a preset time period. When the minimum value is determined to be reached within the preset time period, the system uses the current vector angle corresponding to this minimum value as the target current vector angle. This means that under the current operating conditions, controlling the motor operation with the target current vector angle can achieve the minimum total system loss and realize efficient motor operation. It should be noted that the length of the preset time period can be set according to the actual situation. The length of the time period will affect the real-time performance and accuracy of the control, but the specific value is not limited here.

[0098] Specifically, this can be achieved in at least the following two ways:

[0099] Within a preset time period, the total system loss after each preset step size adjustment is recorded, forming a loss data sequence. After the preset time period ends, the loss data sequence is analyzed to find the minimum value, and the current vector angle corresponding to the minimum value is determined as the target current vector angle.

[0100] Within a preset time period, the total system loss is compared in real time. When a new total system loss is found to be less than the current minimum loss, the minimum loss value is updated, and the corresponding current vector angle is recorded. After the preset time period ends, the last recorded current vector angle is determined as the target current vector angle. Compared to Method 1, Method 2 does not require storing the complete loss data sequence, reducing storage and computational load.

[0101] S106. Calculate the d-axis current command and q-axis current command based on the target current vector angle, and output the d-axis current command and q-axis current command to the current loop controller.

[0102] After determining the target current vector angle, the system needs to calculate the d-axis and q-axis current commands based on the target current vector angle, and output the calculated d-axis and q-axis current commands to the current loop controller. The current loop controller adjusts the actual motor current according to the received d-axis and q-axis current commands to track the command values, thereby achieving precise control of the motor. It should be noted that the calculation formulas for the d-axis and q-axis current commands can be derived based on the specific parameters of the motor and the control strategy; the specific calculation formulas are not limited here.

[0103] Specifically, this can be achieved in at least the following two ways:

[0104] Method 1: Based on the target current vector angle and the given current amplitude, the d-axis current command and q-axis current command are directly calculated using sine and cosine functions. Specifically, the target current vector angle can be denoted as β, and the current amplitude as I. Then, the d-axis current command I_d equals Icos(β), and the q-axis current command I_q equals Isin(β).

[0105] Method 2: Utilizing the decomposition relationship of the current vector in the dq coordinate system, the given current vector is decomposed according to the target current vector angle to obtain the d-axis current command and the q-axis current command. Specifically, the magnitude of the current vector can be calculated first based on the given current amplitude, and then the components of the current vector on the d-axis and q-axis can be calculated using the target current vector angle, which are used as the d-axis current command and the q-axis current command, respectively.

[0106] During this step, the following problem may arise: Due to limitations in the response speed and control accuracy of the current loop controller, it cannot accurately track the d-axis and q-axis current commands, resulting in a deviation between the actual current vector angle and the target current vector angle, affecting the control effect. To address this issue, the system can introduce a feedforward compensation stage while outputting the d-axis and q-axis current commands. Specifically, based on the target current vector angle and motor parameters, the ideal motor output torque can be pre-calculated and used as the feedforward compensation amount, superimposed on the output of the current loop controller. This can, to some extent, offset the response delay and control error of the current loop controller, making the actual current vector angle closer to the target current vector angle and improving control accuracy. Simultaneously, the introduction of the feedforward compensation stage does not affect the stability of the current loop controller and can work in conjunction with the current closed-loop control to achieve a better control effect.

[0107] In the above embodiments, when the change in target torque within a preset time period is detected to be greater than a preset threshold, the system can accurately identify the occurrence of the startup condition, reducing the lag and inaccuracy in condition identification. During startup, by rapidly adjusting the current vector angle within a single preset control cycle to increase the permanent magnet torque component and decrease the reluctance torque component, a non-equilibrium state of the torque components is actively created. This state deviates from the maximum torque-to-current ratio (MTPA) operating point, providing sufficient adjustment space for subsequent optimization. Subsequently, the system gradually increases the current vector angle according to preset step sizes, decreasing the permanent magnet torque component and increasing the reluctance torque component. After each preset step adjustment, the total system loss is calculated, and the minimum point of the total system loss is found through systematic loss evaluation. When it is determined that the total system loss reaches its minimum within a preset time period, the corresponding current vector angle is determined as the target current vector angle, achieving precise convergence from the non-equilibrium state to the optimal efficiency state. The d-axis current command and q-axis current command calculated based on the target current vector angle can control the operation of the current loop controller, ensuring that the motor can meet the torque requirements and achieve the lowest system loss under the starting condition, thereby improving the torque response speed and energy utilization efficiency of the permanent magnet assisted synchronous reluctance motor of the water pump or fan under the starting condition.

[0108] The first embodiment described above illustrates the basic optimization process of the cooperative control method for a permanent magnet assisted synchronous reluctance motor. It minimizes system losses by creating an unbalanced torque component state and gradually adjusting the current vector angle. However, in actual motor control, especially under high torque demands or extreme conditions, adjusting the current vector angle may cause the d-axis current or q-axis current to approach or exceed the preset safety upper limit. This can potentially damage the motor windings and controller, and may also lead to control system instability. To address this safety hazard and ensure the reliability of the optimized control process, a current safety monitoring and adaptive adjustment mechanism needs to be introduced based on loss optimization. The following section combines... Figure 2 Another cooperative control method for a permanent magnet assisted synchronous reluctance motor is described in the embodiments of this application:

[0109] Please see Figure 2 This is another flowchart illustrating a collaborative control method for a permanent magnet assisted synchronous reluctance motor in an embodiment of this application.

[0110] S201. Real-time detection of the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current;

[0111] During the operation of the permanent magnet assisted synchronous reluctance motor, the system continuously monitors the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current. These two differences reflect the distance between the current current state and the safe current boundary. The preset upper limits of the d-axis and q-axis currents can be determined based on the design parameters and performance requirements of the motor and controller; their specific values ​​are not limited here. By calculating the first and second differences in real time, the system can monitor whether the d-axis and q-axis currents are approaching or exceeding the safe upper limit, providing a basis for subsequent safety protection. It should be noted that the calculation frequency of the first and second differences can be set according to the system's control cycle and response requirements; this is not limited here.

[0112] The system can use sensors to measure the actual values ​​of the current d-axis current and q-axis current in real time, and then compare them with preset upper limits for d-axis current and q-axis current, respectively, to calculate a first difference and a second difference. Specifically, the first difference is equal to the preset upper limit for d-axis current minus the current actual value of d-axis current, and the second difference is equal to the preset upper limit for q-axis current minus the current actual value of q-axis current.

[0113] The system can also calculate estimated values ​​of the current d-axis current and q-axis current using sine and cosine functions based on the current current vector angle and current amplitude. These estimated values ​​are then compared with preset upper limits for the d-axis and q-axis currents, respectively, to calculate a first difference and a second difference. Specifically, if the current current vector angle is β and the current amplitude is I, then the estimated value of the current d-axis current is equal to Icos(β), and the estimated value of the current q-axis current is equal to Isin(β). The first difference is equal to the preset upper limit for the d-axis current minus the estimated value of the current d-axis current, and the second difference is equal to the preset upper limit for the q-axis current minus the estimated value of the current q-axis current.

[0114] S202. When the first difference or the second difference is less than the preset safety margin, calculate the first proportionality coefficient and the second proportionality coefficient of the permanent magnet torque component and the reluctance torque component in the total torque under the current vector angle.

[0115] When the system detects that the first or second difference is less than the preset safety margin, it indicates that the current d-axis current or q-axis current is approaching the safety upper limit, posing a risk of current overrun. At this point, the system needs to reassess the current torque component distribution ratio to avoid current overrun. Specifically, the system calculates the first and second proportionality coefficients of the permanent magnet torque component and the reluctance torque component in the total torque at the current current vector angle. The first proportionality coefficient represents the proportion of the permanent magnet torque component in the total torque, and the second proportionality coefficient represents the proportion of the reluctance torque component. These two proportionality coefficients reflect the current torque component distribution and provide a basis for subsequent torque reallocation. It should be noted that the preset safety margin can be set according to the system's control accuracy and response requirements. Typically, a small positive value is chosen, such as 5% or 10% of the current upper limit, to allow sufficient adjustment space; no specific limitation is made here.

[0116] The system can calculate the current values ​​of the permanent magnet torque component and the reluctance torque component based on the current current vector angle and motor parameters, using the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component. Then, the current value of the permanent magnet torque component is divided by the total torque to obtain the first proportionality coefficient, and the current value of the reluctance torque component is divided by the total torque to obtain the second proportionality coefficient.

[0117] The system can also calculate the current values ​​of the permanent magnet torque component and the reluctance torque component based on the current d-axis current and q-axis current, using the current expressions for the permanent magnet torque component and the reluctance torque component, respectively. Specifically, the current value of the permanent magnet torque component is equal to the product of the permanent magnet flux linkage and the q-axis current, and the current value of the reluctance torque component is equal to the difference between the d-axis inductance and the q-axis inductance multiplied by the product of the d-axis current and the q-axis current. Then, the current value of the permanent magnet torque component is divided by the total torque to obtain the first proportionality coefficient, and the current value of the reluctance torque component is divided by the total torque to obtain the second proportionality coefficient.

[0118] S203. Based on the first proportional coefficient, the second proportional coefficient, and the current torque demand, determine the target proportional coefficient that makes both the first difference and the second difference not less than the preset safety margin through numerical solution method.

[0119] After obtaining the first and second proportionality coefficients of the current permanent magnet torque component and reluctance torque component to the total torque, the system needs to determine a new torque component distribution ratio such that both the d-axis current and q-axis current do not exceed the safety upper limit. Specifically, based on the first and second proportionality coefficients and the current torque demand, the system uses numerical methods to determine a target proportionality coefficient that ensures both the first and second differences are not less than a preset safety margin. The target proportionality coefficient represents the target proportion of the permanent magnet torque component or reluctance torque component to the total torque under the new torque component distribution ratio. Finding the target proportionality coefficient that satisfies the safety constraints through numerical methods can maintain the original torque component distribution ratio as much as possible while ensuring current safety and reducing torque fluctuations caused by redistribution. It should be noted that common optimization algorithms such as gradient descent, Newton's method, and quasi-Newton methods can be used for numerical solutions; the specific algorithm selection is not limited here.

[0120] The system can use the target proportional coefficient as the optimization variable to establish a single-objective optimization model with the constraint that both the first and second differences are not less than a preset safety margin, and the optimization objective being to minimize the absolute value of the difference between the target proportional coefficient and either the first or second proportional coefficient. Then, a numerical solution algorithm is used to solve this optimization model to obtain the optimal target proportional coefficient that satisfies the constraints.

[0121] The system can also use the target proportional coefficient as an optimization variable to establish a multi-objective optimization model. This model is constrained by the fact that both the first and second differences are not less than a preset safety margin, and the optimization objective is to minimize the weighted sum of the absolute values ​​of the differences between the target proportional coefficient and the first proportional coefficient, and between the target proportional coefficient and the second proportional coefficient. The weights of the two absolute values ​​can be set based on the contributions of the permanent magnet torque component and the reluctance torque component to the total torque. Then, the multi-objective optimization algorithm is used to solve the optimization model to obtain the optimal target proportional coefficient that satisfies the constraints.

[0122] S204. Based on the target proportional coefficient and the current torque requirement, calculate the corresponding d-axis current target value and q-axis current target value according to the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component.

[0123] After determining the target proportional gain, the system needs to calculate the corresponding target values ​​for the d-axis and q-axis currents based on the target proportional gain and the current torque requirement. This process requires calculation using the electromagnetic relationships between the permanent magnet torque component and the reluctance torque component. Specifically, the permanent magnet torque component can be expressed as the product of the permanent magnet flux linkage and the q-axis current, and the reluctance torque component can be expressed as half the product of the difference between the d-axis and q-axis inductance and the d-axis and q-axis currents. Substituting these two electromagnetic relationships into the expression for the total torque, and combining them with the target proportional gain, the target values ​​for the d-axis and q-axis currents can be obtained through mathematical solutions. It should be noted that multiple solutions may appear during the solution process. In this case, the optimal solution can be selected based on the actual situation, such as selecting the solution with the smallest current amplitude to reduce the system's rated capacity and cost. However, the specific selection criteria are not limited here.

[0124] The system can substitute the electromagnetic relationships of the permanent magnet torque component and the reluctance torque component, as well as the expression for the total torque, into the equation for the target proportional coefficient to obtain a system of two quadratic equations concerning the d-axis current and the q-axis current. Using solver functions in mathematical software or programming languages, this system of equations can be solved to obtain the target values ​​for the d-axis current and the q-axis current.

[0125] The system can also substitute the ratio of d-axis current to q-axis current into the equation for the target proportionality coefficient to obtain an expression for the ratio of d-axis current to q-axis current. Then, substituting this ratio expression into the expression for total torque yields a quadratic equation in q-axis current. Solving this quadratic equation using the quadratic formula provides the target value of the q-axis current, and the target value of the d-axis current is then calculated based on the ratio.

[0126] S205. Convert the target values ​​of the d-axis current and the q-axis current into the adjusted current vector angle;

[0127] The system converts the d-axis current target value and the q-axis current target value into an adjusted current vector angle. Specifically, this includes: calculating the current vector amplitude based on the d-axis current target value and the q-axis current target value; and calculating the adjusted current vector angle using the arctangent function based on the d-axis current target value, the q-axis current target value, and the current vector amplitude. The adjusted current vector angle satisfies the following conditions: the d-axis current target value is equal to the product of the current vector amplitude and the cosine of the adjusted current vector angle, and the q-axis current target value is equal to the product of the current vector amplitude and the sine of the adjusted current vector angle.

[0128] This step converts the target d-axis and q-axis current values ​​calculated in step S204 into adjusted current vector angles. The current vector angle is the angle between the current vector and the d-axis, determining the relative magnitudes of the d-axis and q-axis currents. By adjusting the current vector angle, the distribution ratio of the d-axis and q-axis currents can be changed, thus affecting the magnitudes of the permanent magnet torque and reluctance torque components. The purpose of this step is to solve for the optimal current vector angle based on the optimized d-axis and q-axis current target values, serving as the starting point for subsequent optimization iterations. Different mathematical methods can be used for this solution; no specific method is limited here.

[0129] The system can implement this step in at least two of the following ways:

[0130] Method 1: Calculate the current vector angle directly using the arctangent function based on the target values ​​of the d-axis and q-axis currents. First, the system calculates the magnitude of the current vector, i.e., sqrt(Id_target^2 + Iq_target^2), where Id_target and Iq_target are the target values ​​of the d-axis and q-axis currents, respectively. Then, the system uses the arctangent function atan2(Iq_target, Id_target) to calculate the current vector angle. This function can solve for the angle between the d-axis and q-axis currents. Finally, the calculated current vector angle is used as the adjusted current vector angle.

[0131] Method 2: Solving for the current vector angle using a current circle. In the dq coordinate system, different endpoints of the current vectors form a circle centered at the origin, called the current circle. Given the target values ​​for the d-axis and q-axis currents, a point (Id_target, Iq_target) on the current circle can be determined. Starting from this point, the system traverses the current circle at a preset search step size, calculating the current vector angle at each point, until a current vector angle is found that makes the corresponding d-axis and q-axis currents closest to the target values. This current vector angle is then used as the adjusted current vector angle.

[0132] S206. Starting from the adjusted current vector angle, repeat the step of gradually increasing the current vector angle according to the preset step size.

[0133] This step restarts the incremental optimization process of the current vector angle after the safety adjustment of the current vector angle is completed. Since a current vector angle that satisfies the current constraint condition has already been obtained in step S205, this current vector angle can be used as the starting point for a new round of optimization search. Starting from the adjusted current vector angle, the system gradually increases the current vector angle according to the preset step size, repeating steps S202 to S205 until the maximum number of iterations is reached or other optimization termination conditions are met. By restarting the optimization process, the search for the optimal current vector angle that minimizes system losses can continue while ensuring current safety. At the same time, due to the adjustment of the starting position, the direction and path of the optimization search will also change, which helps to escape possible local optima and improve the global optimization capability.

[0134] In the above embodiments, by real-time detection of the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current, the damage caused by current over-limit during the optimization process to the motor and control system is reduced. When the first or second difference is less than the preset safety margin, the system can promptly identify potential current over-limit risks. Based on the first proportional coefficient, the second proportional coefficient, and the current torque demand, a target proportional coefficient is determined through numerical solution methods to ensure that both the first and second differences are not less than the preset safety margin. This process reallocates the torque component proportions under the premise of ensuring current safety, realizing torque optimization allocation under safety constraints. According to the target proportional coefficient and the current torque demand, the corresponding target values ​​of the d-axis current and q-axis current are calculated according to the electromagnetic relationship between the permanent magnet torque component and the reluctance torque component, ensuring that the reallocated torque components can meet the total torque demand. The target values ​​of the d-axis current and q-axis current are converted into adjusted current vector angles, and the step of gradually increasing the current vector angle according to the preset step size is restarted from the adjusted current vector angle, realizing the safe restart and continuation of the optimization process. This safety protection and adaptive adjustment mechanism ensures that the optimized control process will not reach the current limit boundary under any operating condition, while maintaining the continuity and effectiveness of loss optimization, thereby improving the reliability and practicality of the control system.

[0135] Furthermore, in another embodiment, after outputting the d-axis current command and q-axis current command to the current loop controller, the system also detects in real time the difference between the current loss value of the permanent magnet assisted synchronous reluctance motor and the initial reference loss value to obtain the amount of motor loss reduction;

[0136] Detect the power increase of the DC / DC converter and charger that share a power supply with the permanent magnet assisted synchronous reluctance motor;

[0137] When the reduction in motor losses is greater than a preset redistribution threshold, and the power increase of at least one of the DC / DC converter and charger is greater than a preset transfer threshold, calculate the total power increase of the DC / DC converter and charger.

[0138] When the increase in total power is greater than the decrease in motor losses, it is determined that an increase in global energy consumption has occurred.

[0139] Obtain the output voltage adjustment range of the DC / DC converter and the charging current adjustment range of the charger;

[0140] While keeping the target current vector angle constant, adjust the output voltage of the DC / DC converter and the charging current of the charger so that the increase in total power is not greater than the reduction in motor losses.

[0141] The adjusted output voltage command is sent to the DC / DC converter, and the adjusted charging current command is sent to the charger.

[0142] Specifically, adjusting the output voltage of the DC / DC converter and the charging current of the charger includes: acquiring power loss data of the DC / DC converter under different output voltages and power loss data of the charger under different charging currents;

[0143] Within the output voltage adjustment range, the output voltage of the DC / DC converter is increased in preset voltage steps, and the corresponding power loss value is recorded; within the charging current adjustment range, the charging current of the charger is decreased in preset current steps, and the corresponding power loss value is recorded.

[0144] Calculate the total power loss of the DC / DC converter and charger under each voltage step and each current step combination;

[0145] Select the target combination of voltage and current step sizes that minimizes the total power loss and is not greater than the reduction in motor loss.

[0146] The output voltage corresponding to the target combination is used as the adjusted output voltage command, and the charging current corresponding to the selected target combination is used as the adjusted charging current command.

[0147] After outputting optimized d-axis and q-axis current commands, the system also needs to monitor in real time the reduction in motor losses and the power increase of the DC / DC converter and charger that share power with the motor. When the reduction in motor losses exceeds a preset redistribution threshold, and the power increase of at least one of the DC / DC converter and charger exceeds a preset transfer threshold, it indicates that optimized control may lead to an increase in the total power consumption of the power supply, and power coordination is required.

[0148] The system first calculates the total power increase of the DC / DC converter and charger and compares it with the reduction in motor losses. If the total power increase is greater than the reduction in motor losses, a global energy consumption increase is identified. The system then needs to adjust the output voltage of the DC / DC converter and the charging current of the charger to reduce their power consumption, ensuring that the total power increase does not exceed the reduction in motor losses. During the adjustment process, to maintain the effectiveness of optimized motor control, the system must keep the target current vector angle constant.

[0149] To achieve optimal power coordination, the system employs a voltage-current step-size search method. First, the system acquires power loss data for the DC / DC converter at different output voltages and for the charger at different charging currents, using this data as the basis for adjustment. Then, within the output voltage adjustment range, the system increases the DC / DC converter's output voltage in preset voltage steps, recording the power loss value at each voltage step. Simultaneously, within the charging current adjustment range, the system decreases the charger's charging current in preset current steps, recording the power loss value at each current step. By traversing all possible voltage-current step-size combinations, the system can calculate the total power loss of the DC / DC converter and charger for each combination.

[0150] Finally, the system selects a target combination of voltage and current step sizes that minimizes the total power loss and is no greater than the reduction in motor losses. The output voltage corresponding to this combination is used as the adjusted output voltage command, and the charging current corresponding to this combination is used as the adjusted charging current command. These commands are then sent to the DC / DC converter and charger, respectively. In this way, the system can minimize power consumption while ensuring optimized motor control, achieving global energy efficiency optimization.

[0151] In the above embodiments, by monitoring the relationship between the reduction in motor losses and the increase in power of the DC / DC converter and charger in real time, the system can promptly detect global energy consumption deterioration that may result from local optimization, avoiding the technical flaw of simply pursuing motor efficiency improvement while neglecting energy balance. When the energy-saving effect of reduced motor losses is offset by the increase in power of other devices, the system can automatically identify and activate the global energy balance adjustment mechanism to ensure optimal energy management. By setting redistribution and transfer thresholds, the system can trigger coordinated control only when the benefits of improved motor efficiency are sufficiently significant, avoiding system stability issues that may arise from frequent adjustments. By adjusting the output voltage of the DC / DC converter and the charging current of the charger while keeping the target current vector angle constant, the optimal operating state of the motor is maintained. Global energy consumption rebalancing is achieved through parameter optimization of peripheral devices, ensuring that the energy savings from improved motor efficiency are converted into energy consumption reductions, rather than being consumed by the increased energy consumption of other devices, thereby maximizing the overall efficiency of the power system.

[0152] The system in the embodiments of this invention is described below from the perspective of hardware processing. Please refer to [link / reference needed]. Figure 3 This is a schematic diagram of the physical device structure of a cooperative control system for a permanent magnet assisted synchronous reluctance motor provided in an embodiment of this application.

[0153] It should be noted that, Figure 3 The structure of the system shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of the present invention.

[0154] like Figure 3 As shown, the system includes a Central Processing Unit (CPU) 301, which can perform various appropriate actions and processes based on a program stored in Read-Only Memory (ROM) 302 or a program loaded from storage portion 308 into Random Access Memory (RAM) 303, such as executing the methods described in the above embodiments. The RAM 303 also stores various programs and data required for system operation. The CPU 301, ROM 302, and RAM 303 are interconnected via a bus 304. An Input / Output (I / O) interface 305 is also connected to the bus 304.

[0155] The following components are connected to I / O interface 305: input section 306 including a camera, infrared sensor, etc.; output section 307 including a liquid crystal display (LCD) and speakers, etc.; storage section 308 including a hard disk, etc.; and communication section 309 including a network interface card such as a LAN (Local Area Network) card and a modem, etc. Communication section 309 performs communication processing via a network such as the Internet. Drive 310 is also connected to I / O interface 305 as needed. Removable media 311, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 310 as needed so that computer programs read from them can be installed into storage section 308 as needed.

[0156] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing computer programs for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 309, and / or installed from removable medium 311. When the computer program is executed by central processing unit (CPU) 301, it performs the various functions defined in the present invention.

[0157] It should be noted that the computer-readable medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, wherein a computer-readable computer program is carried. The transmitted data signal can take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof.

[0158] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0159] In another aspect, the present invention also provides a computer-readable storage medium, which may be included in the system described in the above embodiments; or it may exist independently and not assembled into the system. The storage medium carries one or more computer programs that, when executed by a processor of a system, cause the system to implement the methods provided in the above embodiments.

[0160] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0161] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is interpreted as "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".

[0162] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0163] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for cooperative control of a permanent magnet assisted synchronous reluctance machine, characterized in that, The method comprises the following steps: Based on the real-time detected stator current and rotor position of the permanent magnet assisted synchronous reluctance motor, the permanent magnet torque component and the reluctance torque component are calculated respectively, specifically including: Receiving the stator current and rotor position of the permanent magnet assisted synchronous reluctance motor sent by the sensor; Based on the stator current and the rotor position, the d-axis current and the q-axis current are obtained by coordinate transformation; The product of the permanent magnet flux linkage and the q-axis current is determined as the permanent magnet torque component; The difference between the d-axis inductance and the q-axis inductance is multiplied by the product of the d-axis current and the q-axis current to obtain the reluctance torque component; In the case where the change amount of the target torque is greater than the preset threshold value within a preset time, it is determined that the permanent magnet assisted synchronous reluctance motor is in a starting condition; In a single preset control period, the current vector angle is adjusted to increase the permanent magnet torque component and reduce the reluctance torque component, forming a torque component unbalanced state, and the torque component unbalanced state is a state in which the permanent magnet torque component and the reluctance torque component deviate from the maximum torque current ratio MTPA operating point; Starting from the torque component unbalanced state in the starting condition, the current vector angle is gradually increased in a preset step to reduce the permanent magnet torque component and increase the reluctance torque component, and the system total loss is calculated after each preset step adjustment, specifically including: After each preset step adjustment, the corresponding d-axis current and q-axis current are calculated based on the adjusted current vector angle; The stator winding copper loss is calculated according to a stator winding copper loss calculation formula and the d-axis current and the q-axis current, the stator winding copper loss calculation formula being: ; The is the stator winding copper loss, the is the stator resistance, the is the d-axis current, the is the q-axis current; The core loss degree is calculated according to a core loss calculation formula, which is: ; said is the core loss degree, said is the hysteresis loss coefficient, said is the power supply frequency, said is the maximum magnetic flux density, said is the eddy current loss coefficient; The system total loss is obtained by adding the stator winding copper loss and the iron core loss; When it is determined that the system total loss has a minimum value within a preset time period, the current vector angle corresponding to the minimum system total loss is taken as the target current vector angle; Based on the target current vector angle, the d-axis current command and the q-axis current command are calculated, and the d-axis current command and the q-axis current command are output to the current loop controller.

2. The method of claim 1, wherein, After the step of adjusting the current vector angle to increase the permanent magnet torque component and reduce the reluctance torque component in a single preset control period to form a torque component unbalanced state, the method further comprises: Real-time detect the first difference between the current d-axis current and the preset upper limit of the d-axis current, and the second difference between the current q-axis current and the preset upper limit of the q-axis current; When the first difference or the second difference is less than a preset safety margin, the first proportion coefficient and the second proportion coefficient of the permanent magnet torque component and the reluctance torque component in the total torque are calculated under the current vector angle; Based on the first proportion coefficient, the second proportion coefficient and the current torque demand, the target proportion coefficient is determined by a numerical solving method to make the first difference and the second difference not less than the preset safety margin; According to the target proportion coefficient and the current torque demand, the corresponding d-axis current target value and q-axis current target value are calculated according to the electromagnetic relationship of the permanent magnet torque component and the reluctance torque component; The d-axis current target value and the q-axis current target value are converted into an adjusted current vector angle; Re-perform the step of gradually increasing the current vector angle by the preset step size, starting from the adjusted current vector angle.

3. The method of claim 2, wherein, The step of converting the d-axis current target value and the q-axis current target value into an adjusted current vector angle specifically includes: calculating a current vector amplitude according to the d-axis current target value and the q-axis current target value; calculating an adjusted current vector angle based on the d-axis current target value, the q-axis current target value, and the current vector amplitude through an inverse tangent function, the adjusted current vector angle satisfying that the d-axis current target value is equal to the product of the current vector amplitude and the cosine value of the adjusted current vector angle, and the q-axis current target value is equal to the product of the current vector amplitude and the sine value of the adjusted current vector angle.

4. The method of claim 1, wherein, After the step of outputting the d-axis current instruction and the q-axis current instruction to the current loop controller, the method further includes: detecting a difference between a current loss value of the permanent magnet auxiliary synchronous reluctance motor and an initial reference loss value in real time to obtain a motor loss reduction amount; detecting a power increase amount of a DC / DC converter and a charger that share a power supply with the permanent magnet auxiliary synchronous reluctance motor; when the motor loss reduction amount is greater than a preset redistribution threshold value, and the power increase amount of at least one of the DC / DC converter and the charger is greater than a preset transfer threshold value, calculating a total power increase amount of the DC / DC converter and the charger; determining that global energy consumption increases when it is determined that the total power increase amount is greater than the motor loss reduction amount; obtaining an output voltage adjustment range of the DC / DC converter and a charging current adjustment range of the charger; adjusting the output voltage of the DC / DC converter and the charging current of the charger under the premise that the target current vector angle is unchanged, so that the total power increase amount is not greater than the motor loss reduction amount; sending an adjusted output voltage instruction to the DC / DC converter and an adjusted charging current instruction to the charger.

5. The method of claim 4, wherein, The step of adjusting the output voltage of the DC / DC converter and the charging current of the charger specifically includes: obtaining power loss data of the DC / DC converter at different output voltages and power loss data of the charger at different charging currents; incrementing the output voltage of the DC / DC converter by a preset voltage step size within the output voltage adjustment range and recording the corresponding power loss value; and decrementing the charging current of the charger by a preset current step size within the charging current adjustment range and recording the corresponding power loss value; calculating a total power loss of the DC / DC converter and the charger under each voltage step size and each current step size combination; selecting a target combination of voltage step size and current step size with which the total power loss is the smallest and not greater than the motor loss reduction amount; taking the output voltage corresponding to the target combination as the adjusted output voltage instruction and the charging current corresponding to the selected target combination as the adjusted charging current instruction.

6. A coordinated control system for a permanent magnet assisted synchronous reluctance machine, characterized by, The system includes: one or more processors and a memory; the memory coupled with the one or more processors, the memory to store computer program code, the computer program code comprising computer instructions to cause the system to perform the method of any of claims 1-5.

7. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on the system, the system is caused to perform the method of any of claims 1-5.

8. A computer program product, characterised in that, When the computer program product is run on the system, the system is caused to perform the method of any of claims 1-5.

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