Motor energy consumption parameter optimization method and system

Abstract

The present application relates to motor drive control and energy consumption optimization technical field, specifically to a kind of motor energy consumption parameter optimization method and system;Including: obtaining three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage and current output torque, establish energy consumption parameter set and extract working condition statistics;Input preset thermal model estimates rotor temperature and stator winding estimated temperature rise, and temperature compensation correction is carried out to flux linkage constant;With total loss minimum as target, determine cross-axis current instruction and switching frequency under torque, current, voltage and switching frequency constraint;According to mechanical angular velocity, load rate and stator winding temperature discrete generation lookup table;According to transient impact factor, generate feedforward compensation, and update switching frequency to drive motor according to frequency switching criterion, realize actual loss and temperature rise closed loop update;The present application considers load mutation response, thermal demagnetization influence and motor and inverter loss balance.

Description

Technical Field

[0001] This invention relates to the field of motor drive control and energy consumption optimization technology, specifically to a method and system for optimizing motor energy consumption parameters. Background Technology

[0002] In existing motor drive systems, the motor drive system includes a controller, an inverter and a motor body. The controller generates current commands and pulse width modulation signals based on the collected operating parameters such as current, speed, voltage and temperature to drive the motor to operate under different load conditions.

[0003] To balance output performance and operating efficiency, the quadrature shaft current is usually set according to torque requirements, and the inverter is controlled according to a preset switching frequency. Motor drive is achieved by using fixed parameters or a small number of segmented parameters so that the motor can meet the basic torque output requirements under normal operating conditions.

[0004] However, fixed parameters or roughly segmented control methods cannot simultaneously take into account the current response during load changes, the thermal demagnetization effect during continuous operation, and the balance between inverter switching losses and motor losses. This can easily lead to situations where current overshoot exceeds the first preset threshold, temperature rise exceeds the second preset threshold, or switching frequency is unstable under complex operating conditions, resulting in the overall energy consumption of the motor drive system failing to meet the preset energy consumption standards. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for optimizing motor energy consumption parameters, avoiding problems such as current overshoot exceeding a first preset threshold, temperature rise exceeding a second preset threshold, or unstable switching frequency under complex operating conditions. Furthermore, it more easily balances current response during load changes, thermal demagnetization effects, and loss balance between the inverter and the motor, thereby effectively reducing the overall system energy consumption. To achieve the above objectives, this invention adopts the following technical solution:

[0006] A method for optimizing motor energy consumption parameters includes the following steps:

[0007] Step S1: Obtain the operating parameters of the motor drive system, establish a set of energy consumption parameters, and extract operating condition statistics within the preset scheduling window; the operating parameters include at least three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage, and current output torque;

[0008] Step S2: Input the preset thermal model according to the operating parameters and operating condition statistics to estimate the rotor temperature and the stator winding temperature rise, and perform temperature compensation correction on the preset flux linkage constant according to the estimated rotor temperature.

[0009] Step S3: Under the preset torque constraints, current upper limit constraints, voltage upper limit constraints, switching frequency boundary constraints, and frequency switching smoothing constraints, the quadrature-axis current command and switching frequency are determined using the modified flux linkage constant.

[0010] Step S4: Discretize the quadrature axis current command and switching frequency according to the mechanical angular velocity, the load rate determined based on the current output torque, and the stator winding temperature, and generate a quadrature axis current lookup table and a switching frequency threshold lookup table.

[0011] Step S5: Calculate the transient impact factor based on the operating parameters. When the transient impact factor is greater than the calibrated impact trigger threshold, generate a feedforward compensation amount by combining the quadrature axis current lookup table, and perform transient feedforward control on the quadrature axis current closed loop. When the transient impact factor is not greater than the calibrated impact trigger threshold, maintain the current quadrature axis current closed loop control.

[0012] Step S6: According to the switching frequency threshold lookup table, update the switching frequency based on the target switching frequency, the total loss difference, and the preset minimum locking window number as frequency switching criteria; generate a pulse width modulation signal to drive the motor, and collect the actual loss and the actual temperature rise of the stator winding for closed-loop update.

[0013] As a preferred option, the energy consumption parameter set also includes instantaneous sampled values ​​of three-phase stator current, rate of change of speed, quadrature axis current and its rate of change, and estimated loss values; the operating condition statistics include the percentage of load rate intervals, impact event counts, average loss deviation, and frequency switching loss difference within the preset scheduling window.

[0014] Preferably, the temperature compensation correction of the flux linkage constant in step S2 includes at least a linear thermal decay term based on the difference between the rotor temperature and the preset reference temperature, and a high-temperature additional decay term based on the difference between the rotor temperature and the demagnetization risk temperature threshold.

[0015] Preferably, the total loss in step S3 includes copper loss, iron loss, inverter switching loss and harmonic additional loss; the frequency switching smoothing constraint includes the variation amplitude constraint and the cycle time constraint between two adjacent switching frequency updates.

[0016] Preferably, the specific process of transient feedforward control in step S5 includes:

[0017] The transient impact factor is determined based on the rate of change of velocity and the rate of change of quadrature-axis current.

[0018] When the transient impact factor is greater than the impact trigger threshold, an adjustment current is output through a cross-axis current proportional-integral regulator, and a feedforward compensation amount is generated based on the deviation between the cross-axis current command and the current output of the cross-axis current proportional-integral regulator.

[0019] The maximum rate of change of the quadrature-axis current command after superimposed feedforward compensation is limited.

[0020] If the transient impact factor does not exceed the preset exit threshold within a preset number of consecutive control cycles, then the transient feedforward control will exit.

[0021] Preferably, the impact trigger threshold is determined based on the basic impact threshold, the load rate, and the difference between the stator winding temperature and the preset ambient temperature.

[0022] Preferably, the frequency switching criterion in step S6 must simultaneously satisfy the following conditions:

[0023] The target switching frequency is not equal to the currently executed switching frequency;

[0024] The absolute value of the difference between the total loss corresponding to the target switching frequency and the total loss corresponding to the current switching frequency is greater than the preset power hysteresis threshold.

[0025] The cumulative number of scheduling cycles since the last frequency switch has reached the minimum locking window size.

[0026] Preferably, the closed-loop update process in step S6 includes:

[0027] If the deviation between the actual loss and the estimated loss, and / or the deviation between the actual temperature rise of the stator winding and the estimated temperature rise of the stator winding exceeds the corresponding set threshold within multiple consecutive scheduling cycles, then the parameters of the loss estimation model and / or the rotor temperature estimation model will be corrected, the quadrature shaft current command and switching frequency will be re-determined, and the relevant lookup table will be updated; otherwise, the current model parameters and lookup table will remain unchanged.

[0028] A motor energy consumption parameter optimization system includes: a controller, a memory, a motor driver, a data acquisition interface, and a pulse width modulation output interface; the data acquisition interface is used to acquire the operating parameters of the motor drive system, and the pulse width modulation output interface is used to output a pulse width modulation signal to drive the motor; the controller is configured with:

[0029] The parameter acquisition and processing module is used to acquire operating parameters, establish a set of energy consumption parameters, and extract operating condition statistics.

[0030] The state estimation and correction module is used to estimate the rotor temperature and stator winding temperature rise based on the preset thermal model, and to perform temperature compensation correction on the flux linkage constant.

[0031] The optimization module is used to determine the quadrature-axis current command and switching frequency with the goal of minimizing total loss, under multiple safety and smoothing constraints, using a modified flux linkage constant.

[0032] The table generation module is used to discretize instructions and frequency partitions based on running parameters, generate lookup tables, and distribute them.

[0033] The transient feedforward module is used to calculate the transient impact factor and generate a feedforward compensation amount based on a lookup table to perform transient feedforward control when it exceeds the limit;

[0034] The frequency adjustment and closed-loop update module is used to update the switching frequency based on the frequency switching criteria and to collect actual loss and temperature rise data for closed-loop update.

[0035] Each module is used to execute the corresponding step in the above-mentioned motor energy consumption parameter optimization method.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. This invention collects and processes operating parameters such as three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage, and current output torque, and establishes a set of energy consumption parameters and operating condition statistics within a preset scheduling window. This enables systematic statistics on load rate range proportion, impact event count, average loss deviation, and frequency switching loss difference. It can transform the problem of instantaneous sampling being susceptible to noise interference into a stable and usable basis for judging operating conditions, thereby enhancing the accuracy of subsequent thermal estimation and energy consumption optimization.

[0038] 2. This invention estimates the rotor temperature and stator winding temperature rise by introducing a thermal model, and corrects the flux linkage constant based on the rotor temperature. This effectively reflects the thermal demagnetization effect under continuous high load operation, avoids additional losses caused by distributing current according to fixed parameters at room temperature, and thus reduces the temperature rise and energy consumption during continuous operation.

[0039] 3. This invention aims to minimize total losses by uniformly solving for motor losses and inverter losses under preset constraints such as torque constraints, current upper limit constraints, voltage upper limit constraints, switching frequency boundary constraints, and frequency switching smoothing constraints. It can simultaneously coordinate the relationship between copper losses, iron losses, inverter switching losses, and harmonic additional losses, effectively solving the problem of high overall energy consumption caused by the separation of traditional current control and switching frequency control. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application:

[0041] Figure 1 This is a schematic diagram of the steps in the method for optimizing motor energy consumption parameters according to the present invention;

[0042] Figure 2 This is a schematic diagram of a motor energy consumption parameter optimization system provided in an embodiment of this application. Detailed Implementation

[0043] To make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments will be described in detail below with reference to the accompanying drawings.

[0044] This embodiment provides a method for optimizing motor energy consumption parameters. The method uses the three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage and current output torque collected by the motor driver as inputs to form a set of energy consumption parameters and operating condition statistics within the scheduling window.

[0045] The rotor temperature is estimated using a thermal model and the flux linkage constant is corrected. Under the constraints of torque, current, voltage and switching frequency, the quadrature-axis current command and switching frequency that minimize the total loss are obtained. The results are then discretized into a quadrature-axis current lookup table and a switching frequency threshold lookup table for the driver to call according to the operating conditions. When a sudden load change occurs, feedforward compensation and frequency switching criteria are used to complete the motor drive.

[0046] In this way, the current response during sudden load changes, the thermal demagnetization effect during continuous operation, and the balance between inverter switching losses and motor losses can be taken into account simultaneously.

[0047] Please see Figure 1 A method for optimizing motor energy consumption parameters includes the following steps:

[0048] Step S1: Obtain the operating parameters of the motor drive system, establish a set of energy consumption parameters, and extract operating condition statistics within the preset scheduling window; the operating parameters include at least three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage, and current output torque;

[0049] Step S2: Input the preset thermal model according to the operating parameters and operating condition statistics to estimate the rotor temperature and the stator winding temperature rise, and perform temperature compensation correction on the preset flux linkage constant according to the estimated rotor temperature.

[0050] Step S3: Under the preset torque constraints, current upper limit constraints, voltage upper limit constraints, switching frequency boundary constraints, and frequency switching smoothing constraints, the quadrature-axis current command and switching frequency are determined using the modified flux linkage constant.

[0051] Step S4: Discretize the quadrature axis current command and switching frequency according to the mechanical angular velocity, the load rate determined based on the current output torque, and the stator winding temperature, and generate a quadrature axis current lookup table and a switching frequency threshold lookup table.

[0052] Step S5: Calculate the transient impact factor based on the operating parameters. When the transient impact factor is greater than the calibrated impact trigger threshold, generate a feedforward compensation amount by combining the quadrature axis current lookup table, and perform transient feedforward control on the quadrature axis current closed loop. When the transient impact factor is not greater than the calibrated impact trigger threshold, maintain the current quadrature axis current closed loop control.

[0053] Step S6: According to the switching frequency threshold lookup table, update the switching frequency based on the target switching frequency, the total loss difference, and the preset minimum locking window number of the frequency switching criteria; generate a pulse width modulation signal to drive the motor, and collect the actual loss and the actual temperature rise of the stator winding for closed-loop update.

[0054] The energy consumption parameter set also includes instantaneous sampled values ​​of three-phase stator current, rate of change of speed, quadrature axis current and its rate of change, and estimated loss values; operating condition statistics include the percentage of load rate intervals, impact event counts, average loss deviation, and frequency switching loss difference within the preset scheduling window.

[0055] The temperature compensation correction of the flux linkage constant in step S2 includes at least a linear thermal decay term based on the difference between the rotor temperature and the preset reference temperature, and a high-temperature additional decay term based on the difference between the rotor temperature and the demagnetization risk temperature threshold.

[0056] Furthermore, based on the above implementation method, the steps are explained as follows;

[0057] Obtain operating parameters, process the operating parameters based on the data output from the sampling interface, and generate a set of energy consumption parameters and operating condition statistics;

[0058] Operating parameters represent the basic quantities that the driver directly reads during the control cycle, such as the three-phase stator current output by the current sampling circuit, the mechanical angular velocity obtained by the encoder or estimator, the stator winding temperature obtained by the temperature sampling channel, the bus voltage sampling value, and the current output torque; the energy consumption parameter set is directly retained from the above operating parameters or further calculated to form a data set that reflects the trend of energy consumption changes, such as the speed change rate, quadrature axis current, quadrature axis current change rate, and loss estimate;

[0059] The extracted operating condition statistics are summarized within the preset scheduling window to obtain statistical results, such as the load rate range ratio, impact event count, average loss deviation, and frequency switching loss difference. In specific implementation, the three-phase stator current, bus voltage, and stator winding temperature are respectively entered into the internal buffer of the driver through the corresponding acquisition interface. The mechanical angular velocity is written into the control register area by the speed / position acquisition channel. The current output torque can be obtained from the electromagnetic torque estimation value or the upper control setpoint.

[0060] The driver performs coordinate transformation and differential calculation on the sampled values ​​in each control cycle to obtain the quadrature axis current, velocity change rate and quadrature axis current change rate, and writes the results to a local array. The local array is read for statistics after a scheduling window ends, and is immediately overwritten and updated after being read.

[0061] This implementation method captures the linkage between load impact, heat accumulation and loss deviation by performing coordinated statistics on current, speed, temperature and loss estimates. It transforms the disadvantage of single sample values ​​being easily submerged by noise into a more stable and usable judgment basis after window statistics. It can effectively summarize the working conditions based on scheduling window statistics, avoiding misjudgments caused by making control decisions based solely on instantaneous values.

[0062] The current cycle loss estimate is preferably expressed as the sum of copper loss, iron loss, inverter switching loss and harmonic additional loss obtained by forward summation of theoretical loss model based on the current operating state; correspondingly, the actual loss is expressed as the difference between the actual electrical input power and the mechanical output power.

[0063] The mechanical output power can be obtained by multiplying the electromagnetic torque by the mechanical angular velocity; the electromagnetic torque in the case of permanent magnet synchronous motor can be calculated from the number of pole pairs, flux linkage, and direct-axis and quadrature-axis currents; the loss estimate here is not a simple constant, but a basic quantity used to reflect the theoretical current comprehensive energy consumption level of the motor and inverter, and to serve as a benchmark for comparison with actual losses to find model deviations.

[0064] The rate of change of velocity is used to characterize the strength of load disturbance, and the rate of change of quadrature-axis current is used to characterize the speed of current build-up. Together, they determine whether transient feedforward control is needed.

[0065] Obtain operating parameters and operating condition statistics, estimate the rotor temperature and stator winding temperature rise based on the preset thermal model, and determine the corrected flux linkage constant.

[0066] The preset thermal model adopts a lumped parameter model to describe the temperature rise process of stator and rotor thermal nodes, such as a two-node thermal network that includes stator heat capacity, rotor heat capacity, stator and rotor thermal resistance, stator-to-ambient thermal resistance, and rotor-to-ambient thermal resistance.

[0067] Rotor temperature serves as a state variable used to correct the flux linkage constant, while the estimated temperature rise of the stator winding serves as an intermediate result used to determine whether the thermal model matches the actual operation.

[0068] In specific implementation, the estimation execution logic of the dual-node thermal network is as follows: at the end of each preset scheduling window, the estimated temperature of the previous cycle is used as the initial value, the total stator loss is used as the stator thermal input power, the temperature difference between the stator winding and the environment is calculated and divided by the thermal resistance from the stator to the environment as the external heat dissipation power of the stator, and the difference between the rotor temperature and the estimated temperature rise of the stator winding is calculated and divided by the thermal resistance between the stator and the rotor as the internal heat transfer power transferred from the rotor to the stator.

[0069] The net heat flow is obtained by combining the above heat input power, heat dissipation power and heat transfer power. The net heat flow is divided by the stator heat capacity and multiplied by the time length of the scheduling window to obtain the temperature rise increment. The estimated temperature rise of the stator winding in the current window is obtained by iterating through the forward Euler difference equation. The time length of the scheduling window is an integer multiple of the motor driver control cycle.

[0070] Similarly, the rotor net heat flow is obtained by utilizing the rotor's internal losses and internal heat transfer power, divided by the rotor's heat capacity and multiplied by time, and the rotor temperature is iteratively updated. Through this structured lumped parameter difference relationship, the temperature estimation process is transformed into an algebraic operation process with consistent physical dimensions within each scheduling window, thereby enabling the thermal state estimation process to have a clear algebraic analytical relationship.

[0071] The corrected flux linkage constant can be expressed as: the flux linkage constant at the reference temperature multiplied by one minus the product of the linear thermal decay coefficient and the temperature difference between the rotor temperature and the reference temperature, and then minus the product of the high-temperature additional decay coefficient and the excess amount of the rotor temperature exceeding the demagnetization risk temperature threshold; when the rotor temperature is not higher than the demagnetization risk temperature threshold, the excess amount is zero.

[0072] The flux linkage constant at the reference temperature is used to characterize the basic flux linkage capability under calibration conditions. The linear thermal decay coefficient is used to reflect the trend of slow decrease in flux linkage as temperature increases under normal temperature rise conditions. The high-temperature additional decay coefficient is used to reflect the degree of accelerated flux linkage decrease after exceeding the demagnetization risk temperature threshold. The demagnetization risk temperature threshold is used to define the boundary of the magnet entering a high-risk thermal state. The threshold can be determined by the inflection point temperature of the magnet's remanence curve or the calibration results of the no-load back EMF.

[0073] This implementation method directly incorporates the temperature estimation results into the flux linkage correction process, which can accurately reflect the decrease in the actual torque constant after continuous high load. It transforms the disadvantage of insufficient sensitivity of room temperature parameters under high temperature conditions into a control basis that adapts to changes in thermal state. Temperature compensation of the flux linkage constant can be achieved based on rotor temperature estimation, avoiding additional losses caused by distributing current according to the original parameters after flux linkage decay.

[0074] In the thermal model, stator copper loss can be calculated based on the stator resistance and the effective value of the current. The stator resistance is corrected as the stator winding temperature changes. The stator resistance temperature correction is used to characterize the process that the resistance increases after the winding heats up, thereby causing the copper loss to increase further. If this correction is not introduced, the subsequent thermal estimation will underestimate the heating level under continuous load.

[0075] Introducing average loss deviation into operating condition statistics can also be used to verify the output of the thermal model at the scheduling window level, so that thermal estimation does not only depend on the current temperature sampling, but also considers the accumulation of deviations during a period of operation.

[0076] The corrected flux linkage constant is obtained, and the quadrature axis current command and switching frequency are solved according to the objective of minimizing total loss to determine the optimization result that satisfies the constraints. The total loss consists of the sum of copper loss, iron loss, inverter switching loss and harmonic additional loss.

[0077] During the solution process, torque constraints ensure that the output torque meets the current operating conditions, current upper limit constraints ensure that the inverter and motor do not exceed the allowable current range, voltage upper limit constraints ensure that the required voltage vector can be actually output under the current DC bus voltage, switching frequency boundary constraints limit the switching frequency to be within the allowable range, and frequency switching smoothness constraints limit the change amplitude and change cycle between two adjacent switching frequency updates.

[0078] Among them, copper loss characterizes the Joule loss caused by winding current; iron loss reflects the core loss caused by changes in electric angular frequency and equivalent magnetic flux density; inverter switching loss reflects the energy consumption of power devices under different bus voltages, phase currents and switching frequencies; and harmonic additional loss reflects the additional copper loss and additional iron loss introduced by modulation harmonics and dead zone effects.

[0079] In practical implementation, a set of candidate quadrature-axis currents and candidate switching frequencies can be enumerated within the scheduling cycle, the total loss can be calculated separately, and the above constraints can be verified item by item. Only candidate solutions that satisfy all constraints are retained, and then the quadrature-axis current command and switching frequency with smaller total loss are selected from them.

[0080] In this embodiment, when determining the quadrature axis current command, a clear direct axis current control strategy is used by default. For example, a control strategy with zero direct axis current is used for surface-mounted permanent magnet synchronous motors, or a maximum torque-current ratio control strategy with a specific analytical relationship with the quadrature axis current is used for built-in permanent magnet synchronous motors.

[0081] Since the value of the direct-axis current is directly dependent on or equal to zero of the quadrature-axis current, it can be treated as a known constraint term and substituted into the total loss calculation and torque constraint equation during enumeration and solution. The specific algebraic expression of the torque constraint equation is as follows:

[0082]

[0083] in, Based on the current output torque demand benchmark, This represents the number of pole pairs of the motor. This is the corrected flux linkage constant. and These are direct-axis and quadrature-axis inductors, respectively. and These are the direct-axis and quadrature-axis currents, respectively; thus making it possible to solve the quadrature-axis current optimization command separately and ensuring the physical self-consistency of the entire solution model;

[0084] This implementation puts both into the same loss evaluation framework for unified solution, which can capture the impact of current distribution changes on iron loss and copper loss as well as the impact of frequency changes on switching loss and harmonic additional loss. It transforms the disadvantage of previous separate optimization and mutual restraint into a coordinated result after unified evaluation of comprehensive loss. Based on the unified solution of total loss, the quadrature axis current command and switching frequency can be determined in a coordinated manner, avoiding the situation of reducing one type of loss while increasing other losses.

[0085] The mechanical angular velocity, load rate, and stator winding temperature are obtained. Based on the partitioning rules, the quadrature axis current command and switching frequency are discretized to generate a quadrature axis current lookup table and a switching frequency threshold lookup table. The load rate involved is the ratio of the current output torque to the rated torque, which can be divided into segmented ratios such as light load zone, medium load zone, and high load zone.

[0086] The partitioning rules divide the mechanical angular velocity, load rate and stator winding temperature into discrete intervals; the generated quadrature axis current lookup table quickly gives the target quadrature axis current under the corresponding operating conditions during the high-speed control cycle of the driver, while the switching frequency threshold lookup table gives the target switching frequency under the same operating conditions.

[0087] In the actual implementation, the table entries obtained by solving are first written into a contiguous storage area in the controller's memory, and then organized into a data block that can be distributed according to the version number and applicable boundary. After the driver receives the data, it is written into a double-buffered table area. After the current table area completes the call of the current control cycle, it switches to the updated table area, thereby avoiding table lookup interruption. The discretization here is not a simple data compression, but a conversion of the slow solution results into a set of rules that the driver can directly call.

[0088] Temperature zones can be set as low temperature zones, normal temperature zones, and high temperature zones, while speed and load rate zones can be set as several intervals within the rated range of the equipment, so as to balance storage resources and lookup table accuracy. This implementation method can realize the lookup table execution of optimization results based on partition discretization, avoiding repeated complex solutions within the high-speed control cycle.

[0089] The operating parameters are obtained, and the transient impact factor is calculated based on the rate of change of velocity and the rate of change of quadrature-axis current to generate the feedforward compensation amount. The transient impact factor is used to characterize the intensity of load change, and is preferably obtained by weighting the absolute value of the rate of change of velocity and the absolute value of the rate of change of quadrature-axis current.

[0090] The impact trigger threshold serves as the boundary condition for determining whether to initiate transient feedforward control; the feedforward compensation is superimposed on the quadrature-axis current closed-loop output to compensate for the response lag of the proportional-integral loop in the early stages of load impact.

[0091] In practical implementation, the driver reads the mechanical angular velocity and cross-axis current value of the current cycle and the adjacent cycle in each control cycle, obtains the velocity change rate and cross-axis current change rate after differential, and performs weighted calculation in the register area;

[0092] When the transient impact factor is greater than the calibrated impact trigger threshold, the control logic reads the quadrature current command corresponding to the current operating condition from the quadrature current lookup table, constructs the feedforward compensation amount with the difference between the quadrature current command and the current output of the quadrature current closed loop, and writes the superposition result into the current command buffer, and then hands it over to the pulse width modulation calculation stage for calling.

[0093] In contrast, traditional proportional-integral closed-loop circuits often suffer from slow integral build-up and insufficient initial compensation when the load changes abruptly, which can easily lead to current overshoot or torque lag.

[0094] This implementation uses the target quadrature-axis current in the lookup table for targeted compensation, so that the feedforward quantity directly points to a more suitable current level under the current operating condition, thereby approaching the target faster in the initial stage of the impact; the triggering and injection of feedforward compensation can be realized based on the transient impact factor, avoiding significant overshoot caused by the proportional-integral closed loop responding to load changes alone.

[0095] The preset scheduling window further calculates the percentage of load rate intervals, the number of impact events, the average loss deviation, and the frequency switching loss difference. The percentage of load rate intervals reflects the degree of dwell time in different load intervals within the window, which is suitable for determining the main operating intervals of the equipment.

[0096] Impact event count reflects the frequency of load mutations within the window, which is useful for determining whether feedforward compensation parameters need to be strengthened; average loss deviation reflects the average difference between actual loss and loss estimate, which is useful for determining loss model deviation; frequency switching loss difference reflects the change in total loss before and after frequency switching, which is useful for determining whether frequency entries have the effect of reducing loss.

[0097] For highly dynamic industrial manufacturing scenarios, common evaluation benchmarks are not simply based on steady-state efficiency and the actual optimization effect after frequency switching. If a control scheme based solely on instantaneous signals is adopted, these indicators are easily affected by individual abnormal sampling. This implementation method uses window statistics to smooth out the random fluctuations of individual sampling points, providing a more stable basis for subsequent table updates and thermal estimation.

[0098] The switching frequency threshold lookup table is obtained. Based on the frequency switching criteria of the target switching frequency, the difference, and the minimum number of locked windows, the switching frequency is updated. A pulse width modulation signal is generated and the actual loss and the actual temperature rise of the stator winding are collected. The target switching frequency is determined by the corresponding partition of the current mechanical angular velocity, load rate, and stator winding temperature in the switching frequency threshold lookup table.

[0099] The current switching frequency is the switching frequency that was being executed before the switch; the difference is calculated by subtracting the total loss corresponding to the current switching frequency from the total loss corresponding to the target switching frequency; the minimum number of locking windows is limited to the number of scheduling windows that should at least keep the current frequency unchanged since the last frequency switch.

[0100] To achieve this step, the driver first reads the target switching frequency corresponding to the operating condition in the current control cycle, and then compares it with the current switching frequency. If the two are not equal and the difference meets the set improvement conditions, and the cumulative window number since the last switch reaches the minimum locked window number, then the period register value in the pulse width modulation timer is updated to generate a pulse width modulation signal at the corresponding frequency to drive the motor. If the conditions are not met, the current switching frequency is kept unchanged.

[0101] Actual losses can be calculated from the collected voltage and current, and the actual temperature rise of the stator winding can be obtained by comparing the temperature sampling value with the environmental reference or reference temperature; the above results are written back to the scheduling window statistical cache for subsequent verification.

[0102] This implementation introduces dual constraints of difference judgment and minimum locking window number, which can suppress frequency fluctuations in adjacent intervals and transform the additional disturbances caused by frequent switching into a stable execution mode that switches only when the optimization conditions are met; the switching frequency can be updated based on the switching frequency threshold lookup table and frequency switching criteria to avoid modulation instability or repeated fluctuations in loss caused by invalid switching;

[0103] As an application example, this implementation can be deployed in the motor drive system of a continuous rolling mill main drive, a multi-axis heavy-duty robotic arm, or a frequently start-stop conveyor mechanism.

[0104] The controller acquires operating parameters through the current / temperature / voltage acquisition interface and writes the sampled values ​​into the driver's local buffer. The data in the buffer is processed by the control cycle to form quadrature-axis current, speed change rate and loss estimate. At the end of the scheduling window, operating condition statistics are generated. The controller performs thermal model estimation and total loss solution based on the operating condition statistics, forming a new direct-axis current lookup table and a switching frequency threshold lookup table and storing them in memory.

[0105] After the driver calls the current table entry, it outputs a new quadrature-axis current command and pulse width modulation signal based on the transient impact factor and frequency switching criterion. The voltage, current and temperature data generated by the actual operation of the motor are then written back to the corresponding buffer of the sampling interface for the next round of statistics and correction. This forms a complete working process from sampling, estimation, table lookup execution to the feedback of operating results, so that the new operating conditions can be reflected in the subsequent control parameters in a timely manner.

[0106] In this implementation, the controller first clarifies the composition relationship of copper loss, iron loss, inverter switching loss and harmonic additional loss based on the loss model, and then establishes frequency switching smoothing constraints by combining the change amplitude and change rhythm of two adjacent switching frequency updates.

[0107] Meanwhile, the driver calculates the transient impact factor based on the rate of change of speed and the rate of change of quadrature-axis current during the high-speed control cycle. When the triggering condition is met, the quadrature-axis current command obtained from the lookup table is superimposed on the output of the quadrature-axis current proportional-integral regulator at a certain ratio, and a maximum rate of change limit is applied to the superimposed current command. In this way, the current overshoot under sudden operating conditions can be reduced without destroying the original current closed-loop stability.

[0108] In some possible implementations, the total loss in step S3 includes copper loss, iron loss, inverter switching loss and harmonic additional loss; the frequency switching smoothing constraint includes the variation amplitude constraint and the clock cycle constraint between two adjacent switching frequency updates.

[0109] The specific process of transient feedforward control in step S5 includes:

[0110] The transient impact factor is determined based on the rate of change of velocity and the rate of change of quadrature-axis current.

[0111] When the transient impact factor is greater than the impact trigger threshold, an adjustment current is output through a cross-axis current proportional-integral regulator, and a feedforward compensation amount is generated based on the deviation between the cross-axis current command and the current output of the cross-axis current proportional-integral regulator.

[0112] The maximum rate of change of the quadrature-axis current command after superimposed feedforward compensation is limited.

[0113] If the transient impact factor does not exceed the preset exit threshold within a preset number of consecutive control cycles, then the transient feedforward control will exit.

[0114] The impact trigger threshold is determined based on the basic impact threshold, load rate, and the difference between the stator winding temperature and the preset ambient temperature.

[0115] Furthermore, based on the above-described embodiments, the relevant processes are explained as follows;

[0116] Candidate currents and candidate switching frequencies are obtained. Based on the loss model, the total loss is decomposed and calculated to determine the basis for judging the frequency switching smoothness constraint. Copper loss in the total loss represents the Joule heat generated by the winding current, which is directly affected by the stator resistance and the magnitude of the direct-axis and quadrature-axis currents. Iron loss represents the energy consumption of the iron core under the combined action of electric angular frequency and equivalent magnetic flux density.

[0117] Inverter switching losses characterize the energy consumed by power devices during turn-on and turn-off, and are affected by bus voltage, equivalent phase current and switching frequency; harmonic additional losses characterize the additional losses caused by modulation harmonics and dead zone distortion, and are affected by total harmonic distortion of current and current amplitude.

[0118] The inverter switching losses are modeled using an engineering fitting model related to the bus voltage, equivalent phase current, and switching frequency; the additional harmonic losses are modeled using an engineering model related to the square of the total harmonic distortion rate of the current and the square of the equivalent phase current.

[0119] The specific mapping rules for each loss item in the program implementation are as follows: the value of inverter switching loss is set as the product of bus voltage, equivalent phase current and candidate switching frequency, and then multiplied by the switching energy consumption conversion factor specified in the power device manual.

[0120] The additional harmonic loss is set as the product of the reference additional equivalent resistance and the square of the current equivalent phase current, and then multiplied by the square of the total harmonic distortion rate of the current. The total harmonic distortion rate of the current is obtained by calling a pre-stored one-dimensional interpolation table with the switching frequency as the independent variable. The reference additional equivalent resistance is the equivalent resistance value that characterizes the skin effect and proximity effect of high-frequency harmonics. It is obtained by pre-calibrating the motor under rated operating conditions through offline parameter identification or finite element simulation.

[0121] By establishing the above clear algebraic mapping relationship, the components of total loss can be directly obtained based on the determined basic input, without relying on implicit fitting tools that lack explicit expressions; the total harmonic distortion rate of the current involved is not an abstract indicator, but a quantitative indicator that reflects the degree of distortion of the current waveform after the switching frequency changes and the additional heat loss caused therefrom.

[0122] This implementation method incorporates the losses on the motor side and the inverter side into the same evaluation basis, which can more accurately reflect whether a certain frequency adjustment truly brings about a reduction in overall losses; it can achieve a unified assessment of total losses based on the decomposition of multiple loss items, avoiding local optimization from masking the overall increase in losses.

[0123] Obtain the frequency update results of two consecutive switching cycles, and judge the frequency switching smoothness constraint based on the change amplitude and change cycle to determine whether switching is allowed;

[0124] The change amplitude reflects the degree of difference between two adjacent switching frequencies to be executed, such as the cross-zone amplitude when switching from the first preset frequency range to the second preset frequency range; the change beat reflects the density of frequency updates in the scheduling window sequence; both are used together to prevent the frequency from frequently changing back and forth under similar operating conditions.

[0125] In the control flow graph, the specific execution logic of the frequency switching smoothing constraint is represented by two cascaded judgment nodes: checking the absolute value of the difference between the candidate switching frequency and the currently executing switching frequency, and determining that the change amplitude meets the condition only if the absolute value is not greater than the preset maximum allowable step frequency difference;

[0126] The query counts the number of scheduling windows since the last actual frequency switch. Only when the accumulated number is greater than the set minimum beat limit is the change beat condition determined. Only when both amplitude and beat are judged to be passed will the smoothing constraint output the allow flag.

[0127] Although different frequencies may theoretically have different losses in adjacent operating conditions, if the switching is too frequent, the rewriting of the power device control word, the transition of the modulation state, and the change of current ripple may bring additional disturbances. Therefore, in actual implementation, it is not necessary to switch immediately as soon as another frequency with lower loss is found. Instead, it is necessary to first determine whether the frequency change exceeds the allowable update amplitude and whether the preset timer requirement is met between the previous update and the previous update, and then decide whether to write a new pulse width modulation timer period value.

[0128] For high dynamic load scenarios, the smoothness of frequency switching can usually be measured by two engineering benchmarks: whether the current ripple is significantly amplified after switching, and whether the overall loss optimization effect before and after switching is sustained.

[0129] This implementation method, by superimposing variation amplitude and variation rhythm constraints on top of loss and gain, enables frequency switching to take into account both energy consumption optimization and stability; it can achieve conditional adjustment of the switching frequency based on frequency switching smoothness constraints, avoiding modulation disturbances caused by excessive switching.

[0130] The operating parameters are obtained, and the transient impact factor is calculated based on the speed change rate and the quadrature axis current change rate to determine whether to enter transient feedforward compensation. The transient impact factor is obtained by weighting the speed change rate and the quadrature axis current change rate, and it characterizes the impact of load change on the motor control loop.

[0131] The rate of change of velocity reflects how fast the mechanical load changes, while the rate of change of cross-axis current reflects the steepness of the current build-up process. The weights of the two are used to balance the roles of mechanical and current changes in impact judgment. The transient impact factor is used to quantify the typical characteristic of load impact: a sudden change in velocity accompanied by rapid current build-up.

[0132] In practice, the driver performs differential calculations on the mechanical angular velocity and quadrature-axis current in adjacent control cycles, takes the absolute values, and then performs a weighted summation according to preset weights. The weights can be set according to the field tuning results and are used to control the sensitivity to sudden changes in speed and current. Specifically, the sum of the weights of the speed change rate and the quadrature-axis current change rate is 1.

[0133] To balance the differences in response between mechanical and electrical dynamics, the weight of the velocity change rate is positively correlated with the mechanical time constant of the motor, and the weight of the cross-axis current change rate is positively correlated with the electrical time constant of the motor. Preferably, in a low-inertia, high-dynamic system, the weight of the cross-axis current change rate is taken as 0.6 to 0.8, and the weight of the velocity change rate is taken as 0.2 to 0.4, to highlight the precursory effect of current abrupt change.

[0134] This implementation can more accurately distinguish between normal process fluctuations and sudden changes that truly require feedforward intervention; it can identify load changes based on transient impact factors, avoiding the problem of false triggering or missed triggering by a single criterion.

[0135] The system acquires the basic impact threshold, current load rate, stator winding temperature, and ambient temperature. Based on the threshold correction rule, it determines the impact trigger threshold. The basic impact threshold is a reference threshold obtained based on steady-state operating condition statistics. The load rate threshold correction coefficient describes the degree to which the triggering conditions change when the load rate increases. The thermal state threshold correction coefficient describes the degree to which the triggering conditions are adjusted after the stator winding temperature increases relative to the ambient temperature. The current load rate is represented by the ratio of the current output torque to the rated torque. The difference between the stator winding temperature and the ambient temperature reflects whether the motor's thermal state is too high.

[0136] Preferably, the impact trigger threshold can be written as the basic impact threshold plus the product of the load rate threshold correction coefficient and the current load rate, plus the product of the thermal state threshold correction coefficient and the difference between the stator winding temperature and the ambient temperature. The calculation formula is as follows:

[0137]

[0138] in, The impact trigger threshold, Based on the basic impact threshold, This is the load rate threshold correction coefficient. The current load rate, This is the thermal state threshold correction coefficient. Stator winding temperature The ambient temperature;

[0139] In the above formula, the basic impact threshold is used to provide the initial triggering reference under normal process fluctuations, the load rate threshold correction term is used to adjust the triggering sensitivity when the load increases, and the thermal state correction term is used to introduce feedforward in advance when the thermal state deteriorates to prevent the additional impact current from further raising the temperature rise.

[0140] During engineering calibration, the basic impact threshold is taken as 1.2 to 1.5 times the maximum peak value of the transient impact factor collected by the system under rated steady-state conditions; the load rate threshold correction coefficient is calibrated to the value that can increase the impact triggering threshold under full load conditions by 20% to 30% compared with the no-load conditions.

[0141] The thermal state threshold correction coefficient is set to a negative value, and its absolute value is calibrated to reduce the overall impact trigger threshold by 15% to 25% when the stator winding temperature reaches the rated limit, thereby achieving more sensitive feedforward protection intervention at high temperatures.

[0142] This implementation incorporates both load rate and thermal state into the threshold correction, enabling the trigger threshold to adjust according to changes in operating conditions. The impact trigger threshold can be determined based on the basic impact threshold, load rate, and thermal state, avoiding the insufficient adaptability of fixed thresholds under complex operating conditions.

[0143] The system obtains the output of the quadrature-axis current lookup table and the current output of the quadrature-axis current proportional-integral regulator. Based on the feedforward injection ratio, it generates the feedforward compensation amount and limits the maximum rate of change of the superimposed quadrature-axis current command. The feedforward injection ratio controls how much of the difference between the lookup table current target and the proportional-integral output is injected into the final current command. The maximum rate of change limit constrains the slope of the superimposed compensation quadrature-axis current command to prevent excessive compensation from causing new current surges.

[0144] Specifically, when the transient impact factor is greater than the impact trigger threshold, the driver reads the quadrature current command corresponding to the current operating condition from the quadrature current lookup table, calculates the difference between it and the current output of the quadrature current proportional-integral regulator, and then multiplies it by the feedforward injection ratio to obtain the feedforward compensation amount. This compensation amount is then superimposed on the proportional-integral output to form a new quadrature current command, which is then limited according to the preset maximum rate of change and written into the current regulation register.

[0145] The cross-axis current proportional-integral regulator here specifically refers to the regulating element that performs proportional-integral calculations based on speed deviation and outputs a cross-axis current reference value for torque control, i.e., the speed outer loop regulator in a functional sense; therefore, the current output of this regulator and the cross-axis current command read from the lookup table are both current in physical dimensions, with the unit being amperes.

[0146] The difference between the two is used to calculate the deviation, which not only avoids the fundamental error of confusing the dimensions of voltage and current, but also directly reflects the degree of lag of the current closed-loop regulation output relative to the empirical value of the target operating condition in the lookup table; the feedforward injection ratio here is not a simple scaling factor, but a parameter used to balance between compensating for response speed and avoiding over-injection.

[0147] The maximum rate of change limit is used to constrain the change of current command to not exceed the inverter's allowable current build-up capability and the mechanical system's acceptable impact level. The preset maximum rate of change value is not greater than the maximum current rate of change allowed in the safe operating area of ​​the inverter's power devices, and is not greater than the equivalent current rate of change threshold corresponding to the mechanical torsional yield limit of the drive shaft.

[0148] This implementation uses the deviation between the lookup table target and the proportional-integral output as the basis for compensation, which enables the feedforward to be closer to the target required by the current working condition and suppresses secondary overshoot by limiting the amplitude; the feedforward compensation can be generated based on the difference between the lookup table target and the proportional-integral output, avoiding the compensation amount from deviating from the actual working condition or being injected too aggressively.

[0149] The transient impact factor is acquired over multiple consecutive control cycles. Based on the exit threshold, the transient feedforward compensation state is determined for release. The exit threshold is a non-negative threshold not exceeding the impact trigger threshold, serving as a criterion that the impact has significantly weakened. Each control cycle introduces a time-based stability judgment to prevent the state from switching back and forth near the threshold.

[0150] In specific implementation, when continuous When the transient impact factor is less than or equal to the preset exit threshold within a control cycle, the driver exits transient feedforward compensation and resumes conventional closed-loop control dominated by the quadrature-axis current proportional-integral regulator. Here, the exit threshold and the number of consecutive cycles work together to suppress jitter: the former ensures that the impact intensity has indeed been reduced, and the latter ensures that the reduction is not an occasional sampling fluctuation.

[0151] For frequent start-stop or stamping operations, without this release condition, the control logic is prone to frequent switching near the threshold, thereby disrupting the continuity of the current command. This implementation can realize feedforward state release based on exit threshold and continuous cycle judgment, avoiding transient feedforward from staying for a long time or frequent jitter.

[0152] As an application example, this implementation can be applied to a main drive system with significant impact load. The driver reads the mechanical angular velocity quadrature axis current and stator winding temperature data in the sampling register area during the control interrupt, and uses the local computing area to calculate the transient impact factor and impact trigger threshold. If the trigger condition is met, the driver reads the current valid version of the quadrature axis current lookup table entry from the double buffer table area, generates the feedforward compensation amount, and writes it into the quadrature axis current command register area.

[0153] If there are switching frequency adjustment requests at the same time, the frequency switching smoothing constraint judgment must be performed first, and then it is decided whether to rewrite the pulse width modulation timer period register; the current waveform, loss change and temperature rise change obtained after the motor runs continue to be returned through the sampling interface for the next round of threshold correction and feedforward effect evaluation;

[0154] The system includes a controller, memory, motor driver, current / temperature / voltage acquisition interface, and pulse width modulation output interface;

[0155] The controller is used to perform operating parameter processing, thermal state estimation, loss solving and lookup table generation. The motor driver is used to perform table lookup, frequency switching and pulse width modulation output. The memory is used to store model parameters, lookup tables and version information. The current / temperature / voltage acquisition interface is used to write the three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage and current output torque of the motor drive system into the sampling area that the controller can read. The pulse width modulation output interface is used to output the pulse width modulation signal generated by the motor driver to the power device drive side.

[0156] This system allows for the assessment of frequency switching optimization during operation, and determines whether to update the model and lookup table based on actual losses and temperature rise deviations.

[0157] In some possible implementations, the frequency switching criterion in step S6 must simultaneously satisfy the following conditions:

[0158] The target switching frequency is not equal to the currently executed switching frequency;

[0159] The absolute value of the difference between the total loss corresponding to the target switching frequency and the total loss corresponding to the current switching frequency is greater than the preset power hysteresis threshold.

[0160] The cumulative number of scheduling cycles since the last frequency switch has reached the minimum locking window size;

[0161] The closed-loop update process in step S6 includes:

[0162] If the deviation between the actual loss and the estimated loss, and / or the deviation between the actual temperature rise of the stator winding and the estimated temperature rise of the stator winding exceeds the corresponding set threshold within multiple consecutive scheduling cycles, then the parameters of the loss estimation model and / or the rotor temperature estimation model will be corrected, the quadrature shaft current command and switching frequency will be re-determined, and the relevant lookup table will be updated; otherwise, the current model parameters and lookup table will remain unchanged.

[0163] Please see Figure 2 A motor energy consumption parameter optimization system includes: a controller, a memory, a motor driver, a data acquisition interface, and a pulse width modulation output interface;

[0164] The data acquisition interface is used to acquire the operating parameters of the motor drive system, and the pulse width modulation output interface is used to output pulse width modulation signals to drive the motor; the controller is configured with:

[0165] The parameter acquisition and processing module is used to acquire operating parameters, establish a set of energy consumption parameters, and extract operating condition statistics.

[0166] The state estimation and correction module is used to estimate the rotor temperature and stator winding temperature rise based on the preset thermal model, and to perform temperature compensation correction on the flux linkage constant.

[0167] The optimization module is used to determine the quadrature-axis current command and switching frequency with the goal of minimizing total loss, under multiple safety and smoothing constraints, using a modified flux linkage constant.

[0168] The table generation module is used to discretize instructions and frequency partitions based on running parameters, generate lookup tables, and distribute them.

[0169] The transient feedforward module is used to calculate the transient impact factor and generate a feedforward compensation amount based on a lookup table to perform transient feedforward control when it exceeds the limit;

[0170] The frequency adjustment and closed-loop update module is used to update the switching frequency based on the frequency switching criteria and to collect actual loss and temperature rise data for closed-loop update.

[0171] Each module is used to execute the corresponding step in the above-mentioned motor energy consumption parameter optimization method.

[0172] Furthermore, based on the above-described embodiments, the relevant processes are explained as follows;

[0173] Obtain the current mechanical angular velocity, load rate, and stator winding temperature; look up the target switching frequency according to the switching frequency threshold lookup table; and determine the first condition of the frequency switching criterion.

[0174] The target switching frequency is obtained from the switching frequency threshold lookup table for the current operating range; the current switching frequency is the frequency value currently executed by the motor driver; the operating range is composed of the table entry index range divided by mechanical angular velocity, load rate and stator winding temperature.

[0175] In practice, the current / temperature / voltage acquisition interface sends the sampled values ​​into the internal sampling buffer of the controller or driver. The mechanical angular velocity, output torque and temperature values ​​in the buffer are calculated to obtain the load rate, and the driver uses the current index to read the target switching frequency from the switching frequency threshold lookup table.

[0176] If the target switching frequency is not equal to the current switching frequency, then the first condition of the frequency switching criterion is met; the fact that the target switching frequency is not equal to the current switching frequency is used to determine whether the target frequency that satisfies the minimum value condition has changed.

[0177] This implementation uses a lookup table based on operating conditions to synchronize frequency selection with speed, load rate, and thermal status; the target switching frequency can be determined based on the lookup table of switching frequency thresholds, avoiding the use of the same frequency setting for different operating conditions over a long period of time.

[0178] Obtain the total loss corresponding to the target switching frequency and the total loss corresponding to the current switching frequency. Based on the power hysteresis threshold, judge the second condition of the frequency switching criterion. The absolute value of the difference in total loss represents whether the difference in theoretical loss before and after switching meets the set power hysteresis threshold condition. The power hysteresis threshold is a preset non-negative threshold used to filter invalid switching caused by model error or slight fluctuation.

[0179] The basis for setting the power hysteresis threshold is that the switching is considered to have engineering optimization value only when the loss improvement brought by the target frequency exceeds the threshold. If the difference is too small, even if there is a theoretically better frequency, the actual loss improvement effect may not be obtained due to model error, sampling fluctuation or switching disturbance.

[0180] In engineering applications, the power hysteresis threshold is set to 1% to 3% of the average total loss of the system under steady-state operation at the current load rate, in order to ensure that local minimum fluctuations caused by sampling noise or model numerical truncation errors can be effectively filtered out.

[0181] In practice, the controller temporarily stores the total loss value corresponding to the target switching frequency and the total loss value corresponding to the current switching frequency in the loss comparison buffer. The driver reads the absolute value of the difference between the two and compares it with the power hysteresis threshold. The second condition is satisfied only when the absolute value is greater than the preset power hysteresis threshold.

[0182] In the field of adaptive switching frequency control, one of the common evaluation criteria is to evaluate whether the overall loss is reduced after frequency switching, rather than simply pursuing the frequency change itself. Traditional instantaneous switching methods can improve the same action with small losses, but the optimization effect is not obvious and the frequency changes repeatedly.

[0183] This implementation uses a power hysteresis threshold to filter boundary conditions, which can exclude minor differences from the switching conditions; it can also use the power hysteresis threshold to screen for loss benefits, avoiding invalid switching due to insufficient loss improvement.

[0184] The number of preset scheduling cycles accumulated since the last frequency switch is obtained, and the third condition of the frequency switch criterion is judged based on the minimum locking window number. The accumulated number of preset scheduling cycles represents the number of consecutive windows that the current frequency has been maintained. The minimum locking window number is a preset scheduling cycle number of at least 1, which limits the current frequency to be maintained for at least a certain number of scheduling cycles after a switch.

[0185] Since current ripple, device switching thermal state, and loss statistics need to go through a certain window before they have a stable evaluation basis after frequency switching, if the frequency is switched again before the window is reached, it will be difficult to distinguish the energy consumption improvement effect before and after. In specific implementation, the motor driver increments the lock count register at the end of each scheduling cycle and clears the count when frequency switching occurs. When the count value is greater than or equal to the minimum lock window number, the third condition is met.

[0186] This implementation introduces a locking window, which holds the frequency execution result for a window period before allowing the next switch, which helps to reduce jitter near the operating condition boundary; the frequency switching rhythm control can be achieved based on the minimum number of locking windows, avoiding the frequency from changing back and forth within a short window.

[0187] The results of the three criteria are obtained, and the pulse width modulation carrier period parameters are updated or maintained according to the logical AND relationship. The logical AND relationship includes the simultaneous satisfaction of three conditions: the target switching frequency is not equal to the current switching frequency, the absolute value of the difference in total loss is greater than the preset power hysteresis threshold, and the cumulative number of scheduling cycles is greater than or equal to the minimum locking window number. The pulse width modulation carrier period parameters determine the timer period of the pulse width modulation switching frequency.

[0188] In practice, when all three conditions are met, the driver converts the target switching frequency into a new carrier period parameter and writes it into the pulse width modulation timer register. If any condition is not met, the current register value remains unchanged. The writing action here directly corresponds to the actual control field, that is, the pulse width modulation output interface generates a new pulse width modulation signal according to the updated period parameter to drive the inverter power device to work.

[0189] This implementation directly anchors the frequency criteria to the carrier period parameter writing action, making the entire frequency switching chain completely closed; it can directly trigger or prevent the pulse width modulation carrier period parameter update based on the three frequency switching criteria, avoiding the disconnect between control judgment and execution action;

[0190] Obtain the actual loss and estimated loss value, and the actual temperature rise and estimated temperature rise of the stator winding. Based on the deviation threshold, determine whether to perform model parameter correction and lookup table update. The deviation between the actual loss and the estimated loss value is the value obtained by subtracting the estimated loss value from the actual loss. The deviation between the actual temperature rise and the estimated temperature rise of the stator winding is the value obtained by subtracting the estimated temperature rise from the actual temperature rise. The deviation threshold is a non-negative threshold set for each of the above deviations. The scheduling cycle determines whether the deviation persists, rather than allowing occasional exceedances in individual windows.

[0191] The deviation between the actual loss and the estimated loss, and between the actual temperature rise of the stator winding and the estimated temperature rise of the stator winding, is calculated to distinguish between short-term model errors and continuous model mismatch. In specific implementation, the motor driver obtains voltage and current through the sampling interface and calculates the actual loss, and writes the value into the loss feedback buffer. At the same time, the temperature sampling result is compared with the thermal model estimation result to obtain the actual temperature rise deviation and write it into the temperature rise feedback buffer.

[0192] When calculating the actual loss based on the collected voltage and current, this implementation method obtains the actual electrical input power of the system by multiplying and summing the instantaneous values ​​of the three-phase voltage and current.

[0193] For mechanical output power, in scenarios without a physical torque sensor, the torque is output through a state observer within a steady-state window, or by using electromagnetic torque calculations to eliminate the transient torque component caused by mechanical inertia acceleration. The specific formula for extracting the net driving torque is as follows:

[0194]

[0195] in, Net driving torque, This is the calculated value of the electromagnetic torque. The equivalent mechanical moment of inertia of the system, For mechanical angular acceleration, The coefficient of viscous friction, The mechanical angular velocity is obtained by multiplying the net driving torque by the actual sampled mechanical angular velocity.

[0196] Subtracting the mechanical output power from the actual electrical input power yields the actual loss value for the current cycle, thus ensuring that the deviation-driven update mechanism remains fully physically feasible in hardware-constrained engineering implementations.

[0197] The controller reads the deviation data from the two buffers mentioned above and continuously... Threshold comparison is performed within each scheduling cycle: if the actual loss deviation and / or temperature rise deviation continuously exceed the corresponding threshold, the parameters of the loss estimation model and / or rotor temperature estimation model are corrected, the quadrature shaft current command and switching frequency are re-determined, and the quadrature shaft current lookup table and the switching frequency threshold lookup table are updated; if the limits are not continuously exceeded, the current model parameters and the current lookup table remain unchanged.

[0198] The decision condition for M consecutive scheduling cycles is used to suppress the impact of occasional abnormal sampling on update decisions; traditional solutions are often used in a fixed manner for a long time after modeling is completed, without checking actual losses and temperature rise changes, which leads to the gradual accumulation of model deviations; this implementation method triggers updates by continuously exceeding the deviation limit, so that the entries can be corrected as the equipment operating status changes.

[0199] It needs to be further clarified that the specific mechanism for parameter correction of the loss estimation model and / or rotor temperature estimation model is as follows: directional compensation is carried out through incremental step-size iteration based on the deviation direction; for example, when the actual loss is continuously greater than the loss estimate, it indicates that the model is currently underestimating the value, and at this time, the equivalent resistance or iron loss coefficient in the loss estimation model is increased in the positive direction by a preset fixed step size.

[0200] Similarly, when the actual temperature rise of the stator winding is consistently greater than the estimated temperature rise of the stator winding, it indicates that the predicted value of the thermal model is greater than the actual heat dissipation. The stator-to-ambient thermal resistance or rotor-to-ambient thermal resistance parameter in the temperature estimation model needs to be increased by a preset step size to reduce the estimated heat dissipation. Conversely, if the actual value is less than the estimated value, the loss coefficient or thermal resistance parameter should be reduced by the same step size.

[0201] In order to balance the convergence speed of parameter calibration with the stability of the control system, the preset step size is not an absolute constant, but is set as a relative step size that is proportional to the current nominal value of the parameter being corrected, preferably 1% to 3% of the current parameter value;

[0202] Meanwhile, the calibration basis of the deviation threshold is the allowable measurement error tolerance of the system. For example, the deviation threshold of actual loss is set to 3% to 5% of the rated loss of the motor, and the deviation threshold of temperature rise is set to 2 to 4 degrees Celsius, so as to strictly distinguish normal sensor sampling noise from systematic mismatch.

[0203] This iterative correction strategy based on a clear deviation direction and superimposed compensation step size can transform the complex online identification process of nonlinear physical parameters into a well-structured progressive closed-loop calibration logic. This allows the model parameters to smoothly converge to the true physical characteristics within a finite number of scheduling cycles, even in edge drivers with limited computing resources. This implementation can realize the update judgment between the model and the lookup table based on loss deviation and temperature rise deviation, avoiding the long-term accumulation of model mismatch that affects the energy consumption optimization effect.

[0204] The system acquires data from the controller, memory, motor driver, current / temperature / voltage acquisition interface, and pulse width modulation output interface. Based on the functional allocation, it deploys the motor energy consumption parameter optimization system. The parameter acquisition and processing module acquires operating parameters through the current / temperature / voltage acquisition interface, establishes an energy consumption parameter set, and extracts operating condition statistics. The state estimation and correction module performs thermal model calculations and flux linkage temperature compensation. The optimization module determines the quadrature-axis current command and switching frequency under various constraints.

[0205] The table generation module discretizes the data into partitions based on mechanical angular velocity, load rate, and stator winding temperature, and generates lookup tables; the transient feedforward module performs quadrature-axis current feedforward compensation according to the impact criterion; the frequency adjustment and closed-loop update module performs frequency switching criterion, pulse width modulation frequency update, and parameter update after deviation feedback.

[0206] The modules can be deployed in the same controller, or the controller and motor driver can share the work, but the data interaction uses the sampling buffer, lookup table buffer, loss feedback buffer and pulse width modulation timer register as intermediate containers: after the sampled data is written, it is read by the parameter acquisition and processing module, and then enters the calculation buffer.

[0207] After the lookup table is generated, it is written to the double-buffered table area for the driver to call according to the current version; the loss and temperature rise deviation are written to the backhaul buffer area for the closed-loop update module to read at the scheduling cycle boundary; the frequency update result is finally placed in the carrier cycle register corresponding to the pulse width modulation output interface.

[0208] This system architecture ensures that each type of data has a clear write location, read object, and endpoint. This implementation can form a complete system based on the controller, driver, sampling interface, memory, and pulse width modulation output interface, realizing the entire deployment from operating parameter acquisition, model calculation, table lookup execution to deviation update, avoiding the disconnect between control functions and hardware execution links.

[0209] As an application example, this implementation can be deployed in an industrial motor system with an edge controller and an underlying motor driver; the current / temperature / voltage acquisition interface continuously writes the three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage and current output torque into the sampling buffer;

[0210] After the parameter acquisition and processing module reads data from the sampling buffer, it generates operating condition statistics. The state estimation and correction module and the optimization module complete the thermal model estimation and loss solution in the controller. The table generation module writes the newly generated cross-axis current lookup table and switching frequency threshold lookup table into the double buffer table area in the memory and sends them to the motor driver.

[0211] Based on the outputs of the transient feedforward module and the frequency regulation and closed-loop update module, the motor driver rewrites the quadrature-axis current command register and the pulse width modulation carrier period register, and sends out a pulse width modulation signal to drive the motor through the pulse width modulation output interface. The actual loss and the actual temperature rise of the stator winding after the motor runs are returned to the feedback buffer through the sampling interface to determine whether the model parameters and lookup table need to be updated in subsequent scheduling cycles.

[0212] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing motor energy consumption parameters, characterized in that, Includes the following steps: Step S1: Obtain the operating parameters of the motor drive system, establish a set of energy consumption parameters, and extract operating condition statistics within a preset scheduling window; the operating parameters include at least three-phase stator current, mechanical angular velocity, stator winding temperature, DC bus voltage, and current output torque; Step S2: Input the preset thermal model according to the operating parameters and the operating condition statistics to estimate the rotor temperature and the stator winding temperature rise, and perform temperature compensation correction on the preset flux linkage constant according to the estimated rotor temperature. Step S3: Under the preset torque constraint, current upper limit constraint, voltage upper limit constraint, switching frequency boundary constraint and frequency switching smoothing constraint, the modified flux linkage constant is used to determine the quadrature axis current command and switching frequency. Step S4: Discretize the quadrature-axis current command and switching frequency according to the mechanical angular velocity, the load rate determined based on the current output torque, and the stator winding temperature, and generate a quadrature-axis current lookup table and a switching frequency threshold lookup table. Step S5: Calculate the transient impact factor based on the operating parameters. When the transient impact factor is greater than the calibrated impact trigger threshold, generate a feedforward compensation amount in conjunction with the quadrature axis current lookup table and perform transient feedforward control on the quadrature axis current closed loop. When the transient impact factor is not greater than the calibrated impact trigger threshold, maintain the current quadrature axis current closed loop control. Step S6: Update the switching frequency according to the switching frequency threshold lookup table, based on the target switching frequency, the total loss difference, and the preset minimum locking window number as frequency switching criteria. A pulse width modulation signal is generated to drive the motor, and the actual loss and the actual temperature rise of the stator winding are collected for closed-loop updates.

2. The method for optimizing motor energy consumption parameters according to claim 1, characterized in that, The energy consumption parameter set also includes instantaneous sampled values ​​of three-phase stator current, rate of change of speed, quadrature axis current and its rate of change, and estimated loss values; the operating condition statistics include the percentage of load rate intervals, impact event counts, average loss deviation, and frequency switching loss difference within the preset scheduling window.

3. The method for optimizing motor energy consumption parameters according to claim 1, characterized in that, The temperature compensation correction of the flux linkage constant in step S2 includes at least a linear thermal decay term based on the difference between the rotor temperature and the preset reference temperature, and a high-temperature additional decay term based on the difference between the rotor temperature and the demagnetization risk temperature threshold.

4. The method for optimizing motor energy consumption parameters according to claim 1, characterized in that, The total loss in step S3 includes copper loss, iron loss, inverter switching loss, and harmonic additional loss; the frequency switching smoothing constraint includes the variation amplitude constraint and the clock cycle constraint between two adjacent switching frequency updates.

5. The method for optimizing motor energy consumption parameters according to claim 2, characterized in that, The specific process of transient feedforward control in step S5 includes: The transient impact factor is determined based on the rate of change of velocity and the rate of change of cross-axis current. When the transient impact factor is greater than the impact trigger threshold, an adjustment current is output through a cross-axis current proportional-integral regulator, and the feedforward compensation amount is generated based on the deviation between the cross-axis current command and the current output of the cross-axis current proportional-integral regulator. The maximum rate of change of the quadrature-axis current command after superimposing the feedforward compensation is limited; If the transient impact factor does not exceed the preset exit threshold within a preset number of consecutive control cycles, then the transient feedforward control is exited.

6. The method for optimizing motor energy consumption parameters according to claim 5, characterized in that, The impact trigger threshold is determined based on the basic impact threshold, load rate, and the difference between the stator winding temperature and the preset ambient temperature.

7. The method for optimizing motor energy consumption parameters according to claim 1, characterized in that, The frequency switching criterion in step S6 must simultaneously meet the following conditions: The target switching frequency is not equal to the currently executed switching frequency; The absolute value of the difference between the total loss corresponding to the target switching frequency and the total loss corresponding to the current switching frequency is greater than the preset power hysteresis threshold. The cumulative number of scheduling cycles since the last frequency switch has reached the minimum locking window number.

8. The method for optimizing motor energy consumption parameters according to claim 2, characterized in that, The closed-loop update process in step S6 includes: If the deviation between the actual loss and the estimated loss, and / or the deviation between the actual temperature rise of the stator winding and the estimated temperature rise of the stator winding exceeds the corresponding set threshold within multiple consecutive scheduling cycles, then the parameters of the loss estimation model and / or the rotor temperature estimation model will be corrected, the quadrature shaft current command and switching frequency will be re-determined, and the relevant lookup table will be updated; otherwise, the current model parameters and lookup table will remain unchanged.

9. A motor energy consumption parameter optimization system, characterized in that, Includes a controller, memory, motor driver, data acquisition interface, and pulse width modulation output interface; The data acquisition interface is used to acquire the operating parameters of the motor drive system, and the pulse width modulation output interface is used to output pulse width modulation signals to drive the motor. The controller is configured with: The parameter acquisition and processing module is used to acquire the operating parameters, establish a set of energy consumption parameters, and extract operating condition statistics. The state estimation and correction module is used to estimate the rotor temperature and stator winding temperature rise based on the preset thermal model, and to perform temperature compensation correction on the flux linkage constant. The optimization module is used to determine the quadrature-axis current command and switching frequency with the goal of minimizing total loss, under multiple safety and smoothing constraints, using a modified flux linkage constant. The table generation module is used to discretize instructions and frequency partitions based on running parameters, generate lookup tables, and distribute them. The transient feedforward module is used to calculate the transient impact factor and generate a feedforward compensation amount based on a lookup table to perform transient feedforward control when it exceeds the limit; The frequency adjustment and closed-loop update module is used to update the switching frequency based on the frequency switching criteria and to collect actual loss and temperature rise data for closed-loop update. Each module works together to perform the method steps as described in any one of claims 1-8.

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