Mtpa current distribution method, device and medium for marine equipment propulsion motor
Patent Information
- Application Number
- CN202611021489.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-09
- Publication Date
- 2026-10-16
AI Technical Summary
[0004]本申请实施例提供了一种针对海洋装备推进电机的MTPA电流分配方法、设备及介质，解决了现有技术中海洋装备推进电机电流利用率低及铜损较高的技术问题
[0015] This application provides a method, device, and medium for MTPA current distribution in marine equipment propulsion motors. By establishing a linear flux linkage model and a torque model with fixed motor parameters, the method searches for the d-axis and q-axis currents that minimize the square of the current under the target torque constraint. This solves the technical problems of low current utilization and high copper loss in marine equipment propulsion motors in the prior art. It can introduce a reasonable negative d-axis current, make full use of IPMSM reluctance torque, and achieve a trend of reducing copper loss under the same target torque. It also reduces the dependence of MTPA current distribution on two-dimensional flux linkage tables, finite element scanning, and bench calibration.
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Figure CN122932531A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of motor control technology, and in particular to an MTPA current distribution method, device and medium for propulsion motors of marine equipment. Background Technology
[0002] Permanent magnet synchronous motors (PMSMs) are widely used in marine equipment propulsion due to their high efficiency and high power density. With continuous improvements in optimization algorithms such as the maximum torque-to-current ratio (MTPA), PMSMs are evolving towards greater intelligence and efficiency. For marine equipment electric propulsion systems, the propulsion motor is typically housed in a sealed hull, ducted thruster, or compact drive unit, where heat dissipation is limited, and frequent output of varying torques is required. Therefore, for marine equipment propulsion motors, it is necessary to reduce stator current amplitude, minimize copper losses, and improve current utilization while meeting the target torque output.
[0003] In practical motor control and applications, control methods typically set the d-axis current to zero and generate the target torque through the q-axis current. For marine or ocean-going electric propulsion motors, the controller's computing power and sealed heat dissipation conditions are limited. If a control method with zero d-axis current is used, the reluctance torque of the embedded permanent magnet synchronous motor in the electric propulsion system cannot be fully utilized, resulting in low current utilization and high copper losses. During start-up, acceleration / deceleration, attitude maintenance, current disturbance resistance, and near-wall operations, the propulsion load of marine equipment propulsion motors changes frequently. The propulsion motor is often located in a sealed oil chamber, potted structure, or integrated ducted propeller structure, limiting heat dissipation paths. Increased copper losses lead to increased temperature rise in the motor and driver, affecting long-term reliability. Therefore, there is an urgent need for an MTPA current distribution method suitable for marine equipment electric propulsion motors that can reduce stator copper losses under corresponding reluctance torque. Summary of the Invention
[0004] This application provides an MTPA current distribution method, device, and medium for marine equipment propulsion motors, solving the technical problems of low current utilization and high copper loss in existing marine equipment propulsion motors.
[0005] In a first aspect, embodiments of this application provide an MTPA current allocation method for a propulsion motor of marine equipment. The method comprises: determining the target torque and motor parameters of the propulsion motor based on the deviation between the real-time motion state of the propulsion motor and the corresponding desired state under each control mode, and setting a current search interval for the d-axis of the propulsion motor; filtering valid candidate points in the current search interval based on the motor parameters and discrete point torque judgment; calculating the q-axis current corresponding to the valid candidate points based on the target torque; and applying current limiting constraints to the d-axis current and q-axis current corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation.
[0006] In one implementation of this application, setting a current search range for the d-axis of the propulsion motor specifically includes: imposing a negative value limit on the d-axis current to determine the range limit current; and determining the current search range based on the range limit current; wherein the numerical range of the current search range is from the value of the range limit current to 0.
[0007] In one implementation of this application, based on motor parameters, effective candidate points in the current search interval are screened by judging discrete point torque. Specifically, this includes: dividing the current search interval into several discrete candidate points, and calculating the torque parameters corresponding to each candidate point through a preset MTPA optimization target; excluding the corresponding candidate points if the absolute value of the torque parameters is less than a preset threshold; and determining effective candidate points if the absolute value of the torque parameters is greater than or equal to the preset threshold.
[0008] In one implementation of this application, the q-axis current corresponding to the effective candidate point is calculated based on the target torque. Specifically, this includes: calculating the initial q-axis current corresponding to each effective candidate point based on the target torque and the torque parameters corresponding to the effective candidate points; and screening effective candidate points whose initial q-axis current values are not less than 0 to determine the q-axis current corresponding to each effective candidate point after screening.
[0009] In one implementation of this application, current limiting constraints are applied to the d-axis and q-axis currents corresponding to valid candidate points to obtain the optimal allocation current for MTPA current distribution. Specifically, this includes: calculating the sum of the squares of the d-axis and q-axis currents corresponding to valid candidate points to determine the square value of the candidate current corresponding to the valid candidate point; determining whether the square value of the candidate current is within a preset maximum current limiting constraint threshold; if the square value of the candidate current is not within the maximum current limiting constraint threshold, excluding the valid candidate point corresponding to the square value of the candidate current; if the square value of the candidate current is within the maximum current limiting constraint threshold, comparing the square value of the current with the current optimal current value, and selecting the current whose square value is less than the current optimal current value as the optimal allocation current; wherein, the optimal allocation current includes: the optimal d-axis current and the optimal q-axis current.
[0010] In one implementation of this application, before applying current limiting constraints to the d-axis and q-axis currents corresponding to valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method further includes: traversing the d-axis and q-axis currents corresponding to valid candidate points; if no corresponding valid candidate point satisfies the current limiting constraint, setting the d-axis current to 0 and outputting the corresponding first command d-axis current; and calculating the corresponding first command q-axis current based on the target torque and through the current limiting constraint.
[0011] In one implementation of this application, after applying current limiting constraints to the d-axis and q-axis currents corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method further includes: converting the optimal allocation current into the corresponding second command d-axis current and second command q-axis current; calculating the d-axis error and q-axis error corresponding to the second command d-axis current and the second command q-axis current respectively; and integrating the d-axis error and q-axis error according to a preset error ratio coefficient to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor.
[0012] In one implementation of this application, after integrating the d-axis error and q-axis error according to a preset error ratio coefficient to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor, the method further includes: obtaining the rotor angle of the embedded permanent magnet synchronous motor, and mapping the d-axis command and q-axis command to the corresponding stationary αβ coordinate system based on the rotor angle to obtain the converted voltage reference component; and determining the inverter drive signal corresponding to the embedded permanent magnet synchronous motor by sector judgment based on the voltage reference component.
[0013] Secondly, embodiments of this application also provide an MTPA current distribution device for a propulsion motor of marine equipment, characterized in that the device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to implement an MTPA current distribution method for a propulsion motor of marine equipment.
[0014] Thirdly, embodiments of this application also provide a non-volatile computer storage medium for MTPA current distribution of a propulsion motor for marine equipment, storing computer-executable instructions, characterized in that the computer-executable instructions, when executed, can implement an MTPA current distribution method for a propulsion motor for marine equipment.
[0015] This application provides a method, device, and medium for MTPA current distribution in marine equipment propulsion motors. By establishing a linear flux linkage model and a torque model with fixed motor parameters, the method searches for the d-axis and q-axis currents that minimize the square of the current under the target torque constraint. This solves the technical problems of low current utilization and high copper loss in marine equipment propulsion motors in the prior art. It can introduce a reasonable negative d-axis current, make full use of IPMSM reluctance torque, and achieve a trend of reducing copper loss under the same target torque. It also reduces the dependence of MTPA current distribution on two-dimensional flux linkage tables, finite element scanning, and bench calibration. Attached Figure Description
[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A flowchart illustrating an MTPA current distribution method for a propulsion motor of marine equipment, provided in this application embodiment; Figure 2 A comparison diagram of target torque matching error of a marine equipment propulsion motor provided in the embodiments of this application; Figure 3 A schematic diagram of torque matching check for a marine equipment propulsion motor provided in an embodiment of this application; Figure 4 A comparison diagram of the d-axis current of a marine equipment propulsion motor provided for embodiments of this application; Figure 5 A comparison diagram of the q-axis current of a marine equipment propulsion motor provided in this application embodiment; Figure 6 A comparison chart of the squared current values of a marine equipment propulsion motor provided for embodiments of this application; Figure 7 A schematic diagram illustrating the reduction ratio of the current square value relative to the standard method provided in this application embodiment; Figure 8 This is a schematic diagram of the internal structure of an MTPA current distribution device for a propulsion motor of marine equipment, provided as an embodiment of this application. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0018] This application provides a method, device, and medium for MTPA current distribution in marine equipment propulsion motors. By establishing a linear flux linkage model and a torque model with fixed motor parameters, and searching for the d-axis and q-axis currents that minimize the square of the current under target torque constraints, this solves the technical problems of low current utilization and high copper loss in existing marine equipment propulsion motors. It can introduce a reasonable negative d-axis current, fully utilize IPMSM reluctance torque, and achieve a trend of reducing copper loss under the same target torque, reducing the dependence of MTPA current distribution on two-dimensional flux linkage tables, finite element scanning, and bench calibration. The technical solution proposed in this application will be described in detail below with reference to the accompanying drawings.
[0019] Figure 1 This application provides a flowchart of an MTPA current distribution method for a propulsion motor in marine equipment. Figure 1 As shown in the figure, the MTPA current distribution method for a propulsion motor of marine equipment provided in this application embodiment specifically includes the following steps: Step 101: Based on the deviation between the real-time motion state of the marine equipment propulsion motor and the corresponding desired state under each control mode, determine the target torque and motor parameters of the propulsion motor, and set the current search range of the propulsion motor's d-axis.
[0020] For example, marine equipment includes, but is not limited to: underwater robots, remotely operated vehicles, unmanned underwater vehicles, ship auxiliary propulsion devices, marine observation platforms, or underwater operation equipment, with propulsion motors used to drive duct thrusters, propeller thrusters, attitude control thrusters, or underwater operation actuators. In the FOC control of permanent magnet synchronous motors (PMSMs) in marine equipment propulsion motors, conventional control methods typically set the d-axis current to 0 and generate the target torque through the q-axis current. However, for embedded PMSMs, due to the difference in d- and q-axis inductance, the motor can generate additional reluctance torque by introducing an appropriate negative d-axis current < 0. This application, in order to introduce a reasonable negative d-axis current, utilizes IPMSM reluctance torque and limits the negative d-axis current by setting the current search range of the propulsion motor's d-axis, preventing problems such as excessive field weakening, demagnetization risk, or insufficient voltage margin.
[0021] It should be noted that the application of embedded permanent magnet synchronous motors in marine equipment propulsion motors is limited by the computing power of their controllers and the conditions for sealed heat dissipation. Therefore, it is necessary to introduce a reasonable negative d-axis current to reduce the overall trend of copper loss in the motor.
[0022] Specifically, setting the current search range for the d-axis of the propulsion motor includes: imposing a negative value limit on the d-axis current to determine the range limit current; and determining the current search range based on the range limit current. The numerical range of the current search range is from the value of the range limit current to 0.
[0023] In one embodiment, firstly, a relevant model of MTPA current distribution based on parameterized linear flux linkage is constructed for the propulsion motor of marine equipment, serving as the basis for control analysis.
[0024] In existing technologies, the target torque of marine equipment propulsion motors is usually generated by a combination of propulsion controllers, attitude controllers, speed controllers, near-wall operation controllers, or load disturbance compensation. This is achieved by collecting real-time motion status information of the equipment itself, including speed, attitude angle, distance from the wall, and the actual speed and load of the propulsion motor.
[0025] Each controller uses the deviation between its expected and actual feedback values as input, and employs conventional control laws to calculate the required overall thrust or control torque. Specifically, the speed controller focuses on the longitudinal thrust requirement, the attitude controller on the rotational torque requirement in each axis, the propulsion controller directly performs closed-loop torque regulation for each individual thruster, the near-wall operation controller additionally considers distance deviation and wall effects to generate vertical and normal thrust, and load disturbance compensation estimates external disturbances and generates inverse compensation quantities through a state observer. The total control quantity obtained from each control mode is distributed to each thruster according to the corresponding optimization criteria (such as minimum energy consumption or pseudo-inverse allocation), and based on the lever arm length of each thruster, the allocated thrust is converted into the target torque of each propulsion motor. This target torque analysis method is widely used in the control systems of various remotely operated vehicles (ROVs) and underwater vehicles (AUVs).
[0026] Firstly, the linear flux linkage model of linear MTPA can be explained by the following formula.
[0027] (1) (2) in, For d-axis magnetic flux, For permanent magnets, equivalent magnetic flux For q-axis flux linkage, For d-axis inductance, For q-axis inductance, For d-axis current, This is the q-axis current.
[0028] Secondly, a linear IPMSM torque model is constructed, and the general torque formula for PMSM is expressed as: (3) Substituting the aforementioned linear flux linkage model into the general torque formula, we obtain: (4) The simplified linear IPMSM torque model is explained by the following formula.
[0029] (5) in, It is the extreme logarithm; for IPMSM, it is usually set to... ,therefore .
[0030] Furthermore, when and hour, The partial positive value indicates that this item represents positive reluctance torque, which can assist in the output of permanent magnet torque.
[0031] Third, for the linear MTPA optimization problem, the target torque is involved. The specific optimization issues will be explained in detail in the following sections.
[0032] Then, obtain the target torque. and motor parameters , , , , , .
[0033] in, Maximum load current This is the interval limiting current, used to limit the negative d-axis current.
[0034] Set the d-axis current search range to ;in, It is used to limit the negative d-axis current to prevent excessive weakening of magnetism, demagnetization risk, or insufficient voltage margin.
[0035] Step 102: Based on the motor parameters, filter the valid candidate points of the current search interval by judging the discrete point torque.
[0036] For example, in order to maintain the accuracy of torque calculation, it is necessary to limit the current candidate points (into the denominator of the calculation) within the d-axis current search range to prevent division by zero or numerical abnormalities. This application uses discrete point torque judgment to screen valid candidate points in the current search range, thus ensuring the screening of valid candidate points in the current search range.
[0037] Specifically, based on motor parameters, effective candidate points in the current search interval are screened by judging discrete point torque. This includes: dividing the current search interval into several discrete candidate points, and calculating the torque parameters corresponding to each candidate point through a preset MTPA optimization target; excluding the corresponding candidate points if the absolute value of the torque parameter is less than a preset threshold; and determining effective candidate points if the absolute value of the torque parameter is greater than or equal to the preset threshold.
[0038] In one embodiment, firstly, the current search interval is... Divide into several discrete candidate points: .
[0039] Then, for the first The denominator for calculating the torque at candidate points is expressed as: (6) Finally, the judgment absolute value Is it less than That is, to judge Whether it is true or not; among them, To prevent small positive numbers with a denominator of zero.
[0040] if If the condition is met, the candidate point is skipped to avoid division by zero or numerical anomalies; otherwise, the point is set as a valid candidate point.
[0041] Step 103: Calculate the q-axis current corresponding to the effective candidate point based on the target torque.
[0042] For example, the effective candidate point serves as a parameter for calculating torque and constraining. In order to calculate the corresponding q-axis current, this application calculates the q-axis current corresponding to the effective candidate point based on the target torque, thereby realizing the calculation of the q-axis current for a given d-axis current and making full use of IPMSM reluctance torque.
[0043] Specifically, based on the target torque, the q-axis current corresponding to the effective candidate point is calculated, including: calculating the initial q-axis current corresponding to each effective candidate point based on the target torque and the torque parameters corresponding to the effective candidate point; and screening effective candidate points whose initial q-axis current is not less than 0 to determine the q-axis current corresponding to each effective candidate point after screening.
[0044] In one embodiment, firstly, the calculation of the q-axis current under a given d-axis current needs to be determined by torque constraints, and the calculation model is explained by the following formula.
[0045] (7) Furthermore, based on the torque constraint, the q-axis current can be expressed as: (8) The calculation of the q-axis current given the d-axis current is the key calculation process in the MTPA search. For a valid candidate point, its corresponding q-axis current... ,Right now .
[0046] Furthermore, the candidate points corresponding to If the value is less than 0, skip the candidate point. After traversing all candidate points, filter to obtain the q-axis current corresponding to each valid candidate point.
[0047] Step 104: Apply current limiting constraints to the d-axis and q-axis currents corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation.
[0048] For example, this application obtains the optimal allocation current for MTPA current allocation by constraining the d-axis current and q-axis current corresponding to the valid candidate points. This solves the technical problems of low current utilization and high copper loss in marine equipment propulsion motors in the prior art. It can introduce a reasonable negative d-axis current, make full use of IPMSM reluctance torque, and achieve a trend of reducing copper loss under the same target torque. It also reduces the dependence of MTPA current allocation on two-dimensional magnetic flux table, finite element scanning and bench calibration.
[0049] Specifically, current limiting constraints are applied to the d-axis and q-axis currents corresponding to valid candidate points to obtain the optimal allocation current for MTPA current distribution. This includes: calculating the sum of the squares of the d-axis and q-axis currents corresponding to valid candidate points to determine the square value of the candidate current corresponding to the valid candidate point; determining whether the square value of the candidate current is within the preset maximum current limiting constraint threshold; if the square value of the candidate current is not within the maximum current limiting constraint threshold, excluding the valid candidate point corresponding to the square value of the candidate current; if the square value of the candidate current is within the maximum current limiting constraint threshold, comparing the square value of the current with the current optimal value, and selecting the current with a square value less than the current optimal value as the optimal allocation current; wherein, the optimal allocation current includes: the optimal d-axis current and the optimal q-axis current.
[0050] Furthermore, before applying current limiting constraints to the d-axis and q-axis currents corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method also includes: traversing the d-axis and q-axis currents corresponding to the valid candidate points; if no corresponding valid candidate point satisfies the current limiting constraint, setting the d-axis current to 0 and outputting the corresponding first command d-axis current; and calculating the corresponding first command q-axis current based on the target torque and through the current limiting constraint.
[0051] In one embodiment, the objective function for copper loss and current norm is explained by the following formula.
[0052] (9) in, The temperature of the stator winding affects the degree of saturation of resistance and inductance. The temperature of the permanent magnet affects the permanent magnet flux linkage.
[0053] The optimization objective of MTPA is to minimize the square of the current, i.e., the current norm objective function: (10) Under the same resistance and the same current definition, copper loss is proportional to the square of the current. Under the common definition of peak current, the corresponding copper loss can be expressed as: (11) in, Stator copper loss power is one of the main sources of heat generation in motors; The stator phase resistance at temperature The equivalent value under the following can be expressed as: (12) in, The reference temperature for resistance calibration; Reference temperature The stator phase resistance below; is the temperature coefficient of resistance.
[0054] It should be noted that the newly added parameters mentioned above are only used in nonlinear lookup table MTPA control, which requires a two-dimensional magnetic linkage table, interpolation, and a high amount of computation. They are used here for modeling explanation. and The interpretation is still based on the formula in the linear flux linkage model of linear MTPA.
[0055] Furthermore, the square of the candidate current is calculated. and judge The current limit is ;in, This is the preset maximum current limiting threshold.
[0056] If satisfied Obtain the current optimal value and compare it. If If the current is less than the optimal value, then update the optimal current, that is... The corresponding q-axis current and d-axis current are set to the updated optimal current.
[0057] If not satisfied If so, then skip that candidate point.
[0058] After the traversal is complete, if no feasible solution is found, the system can revert to standard control, set the d-axis current to 0, and output the corresponding first command d-axis current. , and according to The current is limited by the value.
[0059] It is important to note that for linear parameter search... , can be represented as , This method uses only linear parameter search. The linear MTPA method does not require a complete two-dimensional magnetic linkage table, thus reducing computational complexity. The nonlinear lookup table MTPA method offers high accuracy but requires a two-dimensional magnetic linkage table, interpolation, and significant computational cost. In the validation code, the linear MTPA can be further enhanced with nonlinear torque correction; that is, candidate parameters are first calculated using linear MTPA. ; fix the Then, the nonlinear flux linkage model is used to solve the problem. This ensures that linear and nonlinear methods can be compared under the same real torque model, thus improving the fairness of the verification.
[0060] Furthermore, after applying current limiting constraints to the d-axis and q-axis currents corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method further includes: converting the optimal allocation current into the corresponding second command d-axis current and second command q-axis current; calculating the d-axis error and q-axis error corresponding to the second command d-axis current and second command q-axis current respectively; and integrating the d-axis error and q-axis error according to a preset error ratio coefficient to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor.
[0061] Furthermore, after integrating the d-axis error and q-axis error according to a preset error ratio coefficient to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor, the method further includes: obtaining the rotor angle of the embedded permanent magnet synchronous motor, and mapping the d-axis command and q-axis command to the corresponding stationary αβ coordinate system based on the rotor angle to obtain the converted voltage reference component; and determining the inverter drive signal corresponding to the embedded permanent magnet synchronous motor by sector judgment based on the voltage reference component.
[0062] In one embodiment, after obtaining the optimal d-axis and q-axis current commands, the actual controller first performs current closed-loop proportional-integral regulation.
[0063] The controller collects the three-phase current of the motor in real time and obtains the feedback d-axis and q-axis currents through coordinate transformation. The command value is subtracted from the feedback value to obtain the d-axis error and q-axis error, respectively. Proportional calculation is performed on each of these errors, that is, the error is multiplied by a proportional coefficient to obtain the proportional term output; at the same time, integral calculation is performed, the errors are accumulated and multiplied by an integral coefficient to obtain the integral term output, and anti-saturation measures are taken to prevent the integral depth from saturating.
[0064] Adding the proportional and integral terms yields the voltage commands for the d-axis and q-axis. The system then enters the space vector pulse width modulation stage, performing an inverse Park transformation. Using the rotor magnetic pole position angle, the d-axis and q-axis voltage commands are converted to a stationary alpha-beta coordinate system, resulting in two-phase stationary voltage components. These two voltage components are then used to determine the sector containing the current target voltage vector, and the duration of action of adjacent effective fundamental vectors and the zero vector is calculated.
[0065] Finally, these action times are converted into three-phase pulse width modulation comparison values, written into the pulse width modulation comparison register of the microcontroller, and used to obtain switching signals to drive the inverter and control the operation of the permanent magnet synchronous motor.
[0066] Regarding the verification results of the method in this application, such as Figure 2-7 As shown, Figure 2 A comparison diagram of target torque matching error of a marine equipment propulsion motor provided in the embodiments of this application; Figure 3 A schematic diagram of torque matching check for a marine equipment propulsion motor provided in an embodiment of this application; Figure 4 A comparison diagram of the d-axis current of a marine equipment propulsion motor provided for embodiments of this application; Figure 5 A comparison diagram of the q-axis current of a marine equipment propulsion motor provided in this application embodiment; Figure 6 A comparison chart of the squared current values of a marine equipment propulsion motor provided for embodiments of this application; Figure 7 This is a schematic diagram illustrating the reduction ratio of the squared current value relative to the standard method provided in an embodiment of this application.
[0067] In one embodiment, the simulation calculation covers approximately to For the target torque range, all three methods calculate the corresponding d-axis and q-axis currents based on the same target torque, and further calculate the actual torque and the square of the current. In the figure, linear MTPA is the method used in this application, and nonlinear MTPA is the reference result of MTPA from a lookup table.
[0068] Depend on Figure 2 and Figure 3 As shown, across the entire target torque range, the standard The method, the recommended simplified MTPA method, and the nonlinear lookup table MTPA reference method can all achieve the target torque matching; among them, the torque matching error is within... The magnitude is within the range of numerical calculation rounding errors. This indicates that the d-axis and q-axis currents calculated by the method in this application can satisfy the basic torque constraints in the MTPA current distribution problem.
[0069] It should be noted that this error is the torque matching error under the static calculation model and should not be interpreted as the dynamic torque pulsation of the actual marine equipment propulsion motor system. This result is mainly used to prove that the method of this application can generate a current distribution solution that satisfies the target torque at the mathematical calculation level.
[0070] Depend on Figure 4 As shown, the standard method always keeps the d-axis current at 0, while the method in this application and the nonlinear lookup table MTPA reference method both gradually introduce negative d-axis current as the target torque increases. This indicates that the method in this application is not a simple q-axis current formula, but rather can utilize the reluctance torque characteristics of the embedded permanent magnet synchronous motor to form a current distribution trend that conforms to the MTPA law.
[0071] In the medium-high torque region, The curves are close to the nonlinear lookup table MTPA reference results, indicating that the method in this application can obtain d-axis current distribution direction and magnitude similar to the lookup table method without requiring a complete nonlinear MTPA lookup table. Depend on Figure 5 As shown, under the same target torque, the standard method corresponds to... Slightly higher; the method in this application and the nonlinear lookup table MTPA reference method. All are lower than the standard method. The reason is that after introducing a negative d-axis current in the method of this application, the motor can make additional use of the reluctance torque component, thus reducing the q-axis current required to achieve the same target torque.
[0072] The results show that the method of this application has embodied the basic physical meaning of MTPA: by reasonably distributing the d-axis and q-axis currents, a unit current can generate more effective torque.
[0073] like Figure 6 As shown, after the target torque increases, the method of this application... It is lower than the standard method and close to the nonlinear lookup table MTPA reference method. This is because the stator copper loss can be expressed as... Therefore, under the same stator resistance conditions, The reduction in copper loss directly corresponds to the reduction in copper loss.
[0074] like Figure 7 As shown, the method of this application and the nonlinear lookup table MTPA reference method, compared with the standard method, The reduction ratio is approximately 3% in the high-torque region. This result demonstrates that although the method in this application does not rely on complex nonlinear MTPA lookup tables, it can still achieve a clear improvement in current utilization compared to the standard current formula.
[0075] The above are embodiments of the method proposed in this application. Based on the same inventive concept, embodiments of this application also provide an MTPA current distribution device for marine equipment propulsion motors, the structure of which is as follows: Figure 8 As shown.
[0076] Figure 8 This is a schematic diagram of the internal structure of an MTPA current distribution device for a propulsion motor of marine equipment, provided as an embodiment of this application. Figure 8 As shown, the device includes: At least one processor 801; And a memory 802 that is communicatively connected to at least one processor; The memory 802 stores instructions that can be executed by at least one processor, which is executed by at least one processor 801 to enable at least one processor 801 to implement, for example, an MTPA current distribution method for a propulsion motor of marine equipment.
[0077] Some embodiments of this application provide corresponding to Figure 1 A non-volatile computer storage medium for MTPA current distribution of propulsion motors for marine equipment stores computer-executable instructions, which, when executed, can realize an MTPA current distribution method for propulsion motors of marine equipment.
[0078] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments for IoT devices and media are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.
[0079] The systems, media, and methods provided in this application are one-to-one correspondences. Therefore, the systems and media also have similar beneficial technical effects as their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the systems and media will not be repeated here.
[0080] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0081] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0082] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0083] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0084] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.
[0085] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.
[0086] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.
[0087] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.
[0088] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A method for MTPA current distribution in marine equipment propulsion motors, characterized in that, The method includes: Based on the deviation between the real-time motion state of the propulsion motor of marine equipment and the corresponding desired state under each control mode, the target torque and motor parameters of the propulsion motor are determined, and the current search range of the d-axis of the propulsion motor is set. Based on the motor parameters, valid candidate points in the current search interval are selected by judging discrete point torque. Calculate the q-axis current corresponding to the effective candidate point based on the target torque; The d-axis current and q-axis current corresponding to the valid candidate points are subject to current limiting constraints to obtain the optimal allocation current for MTPA current allocation.
2. The MTPA current distribution method for propulsion motors of marine equipment according to claim 1, characterized in that, The current search range for the d-axis of the propulsion motor is set, specifically including: The d-axis current corresponding to the d-axis is subject to a negative value limit in order to determine the interval limit current; Based on the interval limiting current, the current search interval is determined; wherein, the numerical range of the current search interval is from the value of the interval limiting current to 0.
3. The MTPA current distribution method for propulsion motors of marine equipment according to claim 1, characterized in that, Based on the motor parameters, valid candidate points in the current search interval are selected by determining discrete point torque, specifically including: The current search interval is divided into several discrete candidate points, and the torque parameters corresponding to each candidate point are calculated through a preset MTPA optimization target. If the absolute value of the torque parameter is less than a preset threshold, the corresponding candidate point is excluded. If the absolute value of the torque parameter is greater than or equal to a preset threshold, the valid candidate point is determined.
4. The MTPA current distribution method for propulsion motors of marine equipment according to claim 1, characterized in that, Based on the target torque, the q-axis current corresponding to the effective candidate point is calculated, specifically including: Based on the target torque and the torque parameters corresponding to the effective candidate points, calculate the initial q-axis current corresponding to each effective candidate point; Valid candidate points with values not less than 0 in the initial q-axis current are selected to determine the q-axis current corresponding to each valid candidate point after selection.
5. The MTPA current distribution method for marine equipment propulsion motors according to claim 1, characterized in that, Apply current limiting constraints to the d-axis current and q-axis current corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current distribution, specifically including: Calculate the sum of the squares of the d-axis current and the q-axis current corresponding to the valid candidate point to determine the square value of the candidate current corresponding to the valid candidate point; Determine whether the candidate current square value is within the preset maximum current limit constraint threshold. If the candidate current square value is not within the maximum current limit constraint threshold, exclude the valid candidate point corresponding to the candidate current square value. When the candidate current square value is within the maximum current limit constraint threshold, the current square value is compared with the current optimal value, and the current whose current square value is less than the current optimal value is selected as the optimal allocation current; wherein, the optimal allocation current includes: the optimal d-axis current and the optimal q-axis current.
6. The MTPA current distribution method for a propulsion motor of marine equipment according to claim 1, characterized in that, Before applying current limiting constraints to the d-axis current and q-axis current corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method further includes: Iterate through the d-axis current and q-axis current corresponding to the valid candidate points. If there is no corresponding valid candidate point that satisfies the current limiting constraint, set the d-axis current to 0 and output the corresponding first command d-axis current. Based on the target torque, the corresponding first command q-axis current is calculated through current limiting constraints.
7. The MTPA current distribution method for a propulsion motor of marine equipment according to claim 1, characterized in that, After applying current limiting constraints to the d-axis current and q-axis current corresponding to the valid candidate points to obtain the optimal allocation current for MTPA current allocation, the method further includes: The optimal allocation current is converted into the corresponding second command d-axis current and second command q-axis current; Calculate the d-axis error and q-axis error corresponding to the d-axis current and q-axis current of the second command, respectively; Based on a preset error ratio coefficient, the d-axis error and the q-axis error are integrated to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor.
8. The MTPA current distribution method for a propulsion motor of marine equipment according to claim 7, characterized in that, After integrating the d-axis error and the q-axis error according to a preset error ratio coefficient to obtain the d-axis command and q-axis command corresponding to the embedded permanent magnet synchronous motor, the method further includes: The rotor angle of the embedded permanent magnet synchronous motor is obtained, and based on the rotor angle, the d-axis command and q-axis command are mapped to the corresponding stationary αβ coordinate system to obtain the converted voltage reference component. Based on the voltage reference component, the inverter drive signal corresponding to the embedded permanent magnet synchronous motor is determined by sector judgment.
9. An MTPA current distribution device for propulsion motors of marine equipment, characterized in that, The device includes: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, which are executed by the at least one processor to enable the at least one processor to implement the MTPA current distribution method for a propulsion motor of marine equipment as described in any one of claims 1-8.
10. A non-volatile computer storage medium for MTPA current distribution in marine equipment propulsion motors, storing computer-executable instructions, characterized in that, When the computer-executable instructions are executed, they can implement the MTPA current distribution method for marine equipment propulsion motors as described in any one of claims 1-8.