Motor optimization method, terminal and medium based on pole-slot matching and permanent magnet position

Abstract

The present invention discloses a motor optimization method, terminal and medium based on pole slot matching and permanent magnet position, and relates to the technical field of motor parameter optimization. The method comprises: globally optimizing the motor parameters of the target motor through a genetic algorithm, and the target motor is a hybrid excitation flux switching motor; under different working conditions, obtaining a first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole slot matching after global optimization, and determining the optimal pole slot matching; under different working conditions, obtaining a second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions after global optimization or after the number of pole slots is optimized, and determining the optimal layout position of the permanent magnet. The present invention first globally optimizes the motor parameters, and then optimizes the pole slot matching and / or the permanent magnet position, thereby effectively suppressing the induced voltage pulsation, improving the stability and efficiency of the motor, and finally achieving the purpose of improving the overall performance of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motor parameter optimization, and in particular to a motor optimization method, terminal and medium based on pole-slot matching and permanent magnet position. Background Art

[0002] Hybrid Excitation Machines (HEMs) combine the advantages of permanent magnets and DC excitation windings. Compared with electrically excited synchronous motors, HEMs exhibit higher torque density and efficiency; compared with permanent magnet synchronous motors, HEMs have better flux linkage control capabilities and are more suitable for wide speed range scenarios. Among them, Hybrid Excitation Switched Flux Machines (HESFMs) utilize the flux focusing effect to exhibit higher torque density, which has attracted widespread attention.

[0003] In the research of hybrid excitation motors, parasitic effects such as cogging torque, back EMF harmonics, torque pulsation, unbalanced magnetic force and loss have been studied in depth. However, the important parasitic effect of DC excitation winding induced voltage pulsation has not been studied in depth. The existence of DC excitation winding induced voltage pulsation inevitably brings a series of problems to hybrid excitation motors. Therefore, studying its generation mechanism and proposing corresponding reduction methods have important academic and application value.

[0004] In summary, the existing technology still needs to be improved and developed. Summary of the invention

[0005] The technical problem to be solved by the present invention is that, in view of the above-mentioned defects of the prior art, a motor optimization method, terminal and medium based on pole-slot matching and permanent magnet position are provided, aiming to solve the problem in the prior art that there is a lack of corresponding DC winding induced voltage pulsation weakening method for hybrid excitation motors.

[0006] The technical solution adopted by the present invention to solve the problem is as follows:

[0007] In a first aspect, an embodiment of the present invention provides a motor optimization method based on pole-slot matching and permanent magnet position, the method comprising:

[0008] Determining a target motor to be optimized, wherein the target motor is a hybrid excitation flux switching motor having both permanent magnets and excitation coils and additionally provided with an external iron bridge;

[0009] Under the preset brushless AC control condition, taking the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal, the motor parameters of the target motor are globally optimized by a preset genetic algorithm;

[0010] Under different preset working conditions, a first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole slot combinations after global optimization is obtained, an optimal pole slot combination is determined according to the first analysis image set, and the number of pole slots of the target motor is optimized according to the optimal pole slot combination;

[0011] Under different preset working conditions, a second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions is obtained after global optimization or pole slot number optimization, the optimal layout position of the permanent magnet is determined according to the second analysis image set, and the permanent magnet position of the target motor is optimized according to the optimal layout position.

[0012] In one embodiment, the stator portion of the target motor is used to accommodate armature windings, excitation windings and permanent magnets; the convex rotor is composed of an iron core and does not contain any permanent magnets and coils; both the armature windings and the excitation windings use concentrated non-overlapping windings; the permanent magnets are tangentially magnetized and placed at the center of each stator pole.

[0013] In one embodiment, the genetic algorithm is used to:

[0014] The objective function is established in advance with the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal;

[0015] Randomly generate a number of individuals, wherein each individual represents a parameter setting scheme of the target motor, and the chromosome of each individual is composed of a gene set, and each gene in the gene set represents a motor parameter;

[0016] Calculate the fitness value corresponding to each individual according to the objective function, and determine whether a preset termination condition is currently reached, wherein the termination condition is that a maximum number of iterations is reached or there is an individual whose fitness value reaches a preset threshold;

[0017] If the termination condition is not met currently, the parent population for reproduction is selected according to the fitness value of each individual;

[0018] Performing chromosome crossover recombination on individuals in the parent population to obtain a number of new individuals;

[0019] Continue to execute the step of calculating the fitness value corresponding to each individual according to the objective function until the termination condition is reached, and determine the optimal parameter setting scheme according to the individual with the highest fitness value among all current individuals;

[0020] The motor parameters of the target motor are globally optimized according to the optimal parameter setting scheme.

[0021] In one embodiment, the first analysis image set includes: an analysis image of the excitation winding induced voltage ratio generated by the target motor under different pole-slot combinations changing with the rotor position under each of the no-load condition, the armature current supply only condition and the load condition, and a spectrum analysis image of the excitation winding induced voltage ratio.

[0022] In one embodiment, the second analysis image set includes: an analysis image of the excitation winding induced voltage ratio generated by the target motor under different permanent magnet positions under each of the no-load condition and the loaded condition, which varies with the rotor position, and a spectrum analysis image of the excitation winding induced voltage ratio.

[0023] In one embodiment, the optimal pole-slot matching is: the difference between the number of stator slots and the number of rotor poles is 1 or 2.

[0024] In one embodiment, the optimal layout position is: placing the permanent magnet at the bottom or middle of the motor.

[0025] In one embodiment, the thickness of the added external iron bridge is 0.5 mm.

[0026] In a second aspect, an embodiment of the present invention further provides a terminal comprising a memory and one or more processors; the memory stores one or more programs; the program comprises instructions for executing any of the motor optimization methods based on pole slot matching and permanent magnet position as described above; and the processor is used to execute the program.

[0027] In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium having a plurality of instructions stored thereon, wherein the instructions are suitable for being loaded and executed by a processor to implement the steps of any of the above-described motor optimization methods based on pole-slot matching and permanent magnet position.

[0028] Beneficial effects of the present invention: The embodiment of the present invention first globally optimizes the motor parameters of the hybrid excitation flux switching motor, and then optimizes the pole slot matching and / or the permanent magnet position, thereby effectively suppressing the induced voltage pulsation, improving the stability and efficiency of the motor, and ultimately achieving the purpose of improving the overall performance of the motor. The problem of the lack of a corresponding method for weakening the induced voltage pulsation of the DC winding for the hybrid excitation motor in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a flow chart of a motor optimization method based on pole-slot matching and permanent magnet position provided in an embodiment of the present invention.

[0031] Figure 2 It is a topological structure diagram of a hybrid excitation flux switching motor provided in an embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the rotor pole slot design dimensions provided in an embodiment of the present invention.

[0033] Figure 4 It is a simulation result diagram of the influence of the iron bridge thickness on the average torque and the flux regulation ratio provided by the embodiment of the present invention.

[0034] Figure 5 This is a waveform diagram of the no-load FW (DC excitation winding) induced voltage ratio of HESFMs with pole-slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles at 400rpm provided by an embodiment of the present invention.

[0035] Figure 6 This is a no-load FW induced voltage ratio spectrum diagram of HESFMs with pole-slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles at 400 rpm provided by an embodiment of the present invention.

[0036] Figure 7 This is a waveform diagram of the no-load FW induced voltage ratio at 400 rpm of HESFMs with pole and slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles provided in an embodiment of the present invention.

[0037] Figure 8 This is a no-load FW induced voltage ratio spectrum diagram of HESFMs with pole and slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles at 400 rpm provided by an embodiment of the present invention.

[0038] Fig. 9 This is a FW induced voltage ratio waveform diagram of HESFMs with pole-slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles provided in an embodiment of the present invention at 400 rpm under excitation of only three-phase armature current.

[0039] Fig.10This is a FW induced voltage ratio spectrum diagram of HESFMs with pole-slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles provided in an embodiment of the present invention under only three-phase armature current excitation at 400 rpm.

[0040] Fig.11 This is a FW induced voltage ratio waveform diagram of HESFMs with pole-slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles provided in an embodiment of the present invention under three-phase armature current excitation at 400 rpm.

[0041] Fig.12 This is a FW induced voltage ratio spectrum diagram of HESFMs with pole-slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles provided by an embodiment of the present invention under only three-phase armature current excitation at 400 rpm.

[0042] Fig.13 This is a waveform diagram of the loaded FW induced voltage ratio at 400 rpm of HESFMs with pole and slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles provided in an embodiment of the present invention.

[0043] Fig.14 This is a spectrum diagram of the loaded FW induced voltage ratio at 400 rpm of HESFMs with pole and slot combinations of 6 slots and 4 poles, 6 slots and 5 poles, 6 slots and 7 poles, and 6 slots and 8 poles provided in an embodiment of the present invention.

[0044] Fig.15 This is a waveform diagram of the loaded FW induced voltage ratio at 400 rpm of HESFMs with pole and slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles provided in an embodiment of the present invention.

[0045] Fig.16 This is a spectrum diagram of the loaded FW induced voltage ratio at 400 rpm of HESFMs with pole and slot combinations of 12 slots and 10 poles, 12 slots and 11 poles, 12 slots and 13 poles, and 12 slots and 14 poles provided in an embodiment of the present invention.

[0046] Fig.17 3 is a waveform diagram of the loaded FW induced voltage ratio of the HESFMs with a pole-slot combination of 6 slots and 4 poles at different full load levels at 400 rpm provided by the embodiment of the present invention.

[0047] Fig.18 It is a topological structure diagram of HESFMs with 12 slots and 10 poles under different permanent magnet positions provided by an embodiment of the present invention.

[0048] Fig.19It is a waveform diagram of the no-load FW induced voltage ratio of a HESFMs with a pole-slot combination of 12 slots and 10 poles at 400 rpm and different permanent magnet positions provided by an embodiment of the present invention.

[0049] Fig. 20 It is a no-load FW induced voltage ratio spectrum diagram of a HESFMs with a pole-slot combination of 12 slots and 10 poles at 400 rpm and different permanent magnet positions provided by an embodiment of the present invention.

[0050] Fig.21 It is a waveform diagram of the FW induced voltage ratio of HESFMs with a pole-slot combination of 12 slots and 10 poles at 400 rpm and different permanent magnet positions provided by an embodiment of the present invention.

[0051] Fig. 22 It is a spectrum diagram of the FW induced voltage ratio under load of HESFMs with a pole-slot combination of 12 slots and 10 poles at 400 rpm and different permanent magnet positions provided by an embodiment of the present invention.

[0052] Fig.23 It is a principle block diagram of a terminal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The present invention discloses a motor optimization method, terminal and medium based on pole slot matching and permanent magnet position. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0054] It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0055] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0056] In view of the above-mentioned defects of the prior art, the present invention provides a motor optimization method based on pole-slot matching and permanent magnet position. By determining the target motor to be optimized, wherein the target motor is a hybrid excitation flux switching motor, which has both permanent magnets and excitation coils, and is additionally provided with an external iron bridge; under the preset brushless AC control conditions, taking the average electromagnetic torque maximization within one electrical cycle as the optimization goal, the motor parameters of the target motor are globally optimized through a preset genetic algorithm; under different preset working conditions, the first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole-slot matching after global optimization is obtained, the optimal pole-slot matching is determined according to the first analysis image set, and the number of pole slots of the target motor is optimized according to the optimal pole-slot matching; under different preset working conditions, the second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions after global optimization or after the number of pole slots is optimized is obtained, the optimal layout position of the permanent magnet is determined according to the second analysis image set, and the position of the permanent magnet of the target motor is optimized according to the optimal layout position. The present invention firstly globally optimizes the motor parameters of the hybrid excitation flux switching motor, and then optimizes the pole-slot matching (i.e., the ratio of the number of stator slots to rotor poles) and / or the position of the permanent magnets, thereby effectively suppressing the induced voltage pulsation, improving the stability and efficiency of the motor, and ultimately achieving the purpose of improving the overall performance of the motor.

[0057] like Figure 1 As shown, the method specifically includes:

[0058] Step S100: determining a target motor to be optimized, wherein the target motor is a hybrid excitation flux switching motor having both permanent magnets and excitation coils and additionally provided with an external iron bridge.

[0059] Specifically, the target motor to be optimized in this embodiment can be any HESFMs that needs to suppress induced voltage pulsation. This embodiment first defines the overall topology of the HESFMs to be optimized. Based on the traditional three-phase flux switching motor (Switched Flux Permanent Magnet, SFPM), the motor replaces part of the permanent magnets with field coils (FCs) and adds an external iron bridge to enhance the flux controllability.

[0060] For example, the topology of a 12-slot, 10-pole three-phase HESFMs is as follows: Figure 2 and Figure 3 The introduction of the magnetic iron bridge provides an additional magnetic flux path for the excitation coil, which helps to alleviate the potential irreversible demagnetization problem of the permanent magnet and further improves the magnetic flux controllability of HESFMs. Determined as:

[0061] , (1);

[0062] In formula (1) , and They are positive excitation current, negative excitation current and no-load phase fundamental back electromotive force under single permanent magnet excitation. The larger it is, the stronger the motor's flux regulation ability is, and vice versa.

[0063] In another implementation, the target motor to be optimized in this embodiment may also be other HESFMs with different topological structures, for example, using an asymmetric three-phase winding layout to generate different magnetic field and induced voltage characteristics.

[0064] In one implementation, the stator portion of the target motor is used to accommodate armature windings, excitation windings and permanent magnets; the convex rotor is composed of an iron core and does not contain any permanent magnets and coils; both the armature windings and the excitation windings use concentrated non-overlapping windings; the permanent magnets are tangentially magnetized and placed at the center of each stator pole.

[0065] Specifically, the structural design of the stator part of the target motor in this embodiment is used to accommodate the armature winding (AW), the field winding (FW) and the permanent magnet (PM). Among them, the convex rotor is composed of an iron core and does not contain any permanent magnets and coils. Both the armature winding and the field winding adopt concentrated non-overlapping windings, which have the advantages of short end windings, strong fault tolerance, low copper loss and high efficiency. The permanent magnet adopts tangential magnetization and is placed at the center of each stator pole.

[0066] In one implementation, the thickness of the added external iron bridge is 0.5 mm.

[0067] Specifically, this embodiment takes into account the special properties of the iron bridge. If the thickness of the iron bridge is too large, it will lead to high leakage magnetic field and reduce the excitation torque of the permanent magnet; if the thickness of the iron bridge is too small, the magnetic flux regulation ability may be limited due to magnetic saturation (such as Figure 4 Therefore, this embodiment recommends selecting an iron bridge with a thickness of 0.5 mm to balance the excitation torque capacity and flux regulation capacity of the permanent magnet.

[0068] Step S200: Under preset brushless AC control conditions, the motor parameters of the target motor are globally optimized by using a preset genetic algorithm with the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal.

[0069] Specifically, this embodiment pre-sets the brushless AC control conditions for the target motor. For example, for a 12-slot 10-pole three-phase HESFMs motor, the brushless AC control conditions can be zero d-axis current, 20W armature winding copper loss, and positive 5A / mm2 DC field winding slot current density. 2 Under the preset brushless AC control conditions, the genetic algorithm is used for global optimization with the goal of maximizing the average electromagnetic torque within one electrical cycle. The main motor parameters after global optimization are listed in Table 1.

[0070] Table 1. Main motor parameters involved in global optimization

[0071]

[0072] In one implementation, the genetic algorithm is used to:

[0073] The objective function is established in advance with the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal;

[0074] Randomly generate a number of individuals, wherein each individual represents a parameter setting scheme of the target motor, and the chromosome of each individual is composed of a gene set, and each gene in the gene set represents a motor parameter;

[0075] Calculate the fitness value corresponding to each individual according to the objective function, and determine whether a preset termination condition is currently reached, wherein the termination condition is that a maximum number of iterations is reached or there is an individual whose fitness value reaches a preset threshold;

[0076] If the termination condition is not met currently, the parent population for reproduction is selected according to the fitness value of each individual;

[0077] Performing chromosome crossover recombination on individuals in the parent population to obtain a number of new individuals;

[0078] Continue to execute the step of calculating the fitness value corresponding to each individual according to the objective function until the termination condition is reached, and determine the optimal parameter setting scheme according to the individual with the highest fitness value among all current individuals;

[0079] The motor parameters of the target motor are globally optimized according to the optimal parameter setting scheme.

[0080] Specifically, a genetic algorithm is an optimization algorithm that simulates natural selection and genetic mechanisms, and can be used to solve complex global optimization problems. In practical applications, it is first necessary to clarify the motor parameters to be optimized, such as the motor speed, torque, etc. Then, one or more optimization targets are determined according to specific needs, and a corresponding objective function is established. In this embodiment, the average electromagnetic torque maximization within an electrical cycle is used as the optimization target. Then, a group of individuals is randomly generated, and each individual represents a group of motor parameters, that is, a parameter setting scheme for a target motor. The representation of individuals can be determined by real number coding or binary coding. Then, the fitness value of each individual is calculated according to the objective function. The higher the fitness value, the better the individual, and the more likely it is to be screened out for breeding the next generation. Then, based on the fitness value of each individual, the parent population for breeding is screened out, and the roulette selection algorithm or the tournament selection algorithm can be used to generate the selection algorithm of the parent population. The selected individuals are subjected to chromosome crossover recombination to obtain several new individuals. The population is updated by new individuals, for example, the new individuals replace some or all of the old individuals. Finally, it is determined whether the termination condition is met. The termination condition set in this embodiment is that the maximum number of iterations is reached or there is an individual whose fitness value reaches a preset threshold. When the termination condition is met, the current optimal individual (i.e., the individual with the highest fitness value) is output to obtain the optimal parameter setting scheme.

[0081] Step S300: Under different preset working conditions, obtain a first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole slot combinations after global optimization, determine the optimal pole slot combination according to the first analysis image set, and optimize the number of pole slots of the target motor according to the optimal pole slot combination.

[0082] Specifically, after the global optimization is completed, in order to further weaken the induced voltage pulsation of the excitation winding of the HESFMs, the present embodiment can also optimize the number of pole slots of the target motor. In practical applications, multiple working conditions are selected in advance, and the situation of the target motor generating the induced voltage ratio of the excitation winding under different working conditions and different pole slot combinations is analyzed, and the analysis results are summarized into a first analysis image set. The pole slot combination that can effectively weaken the induced voltage pulsation of the excitation winding is determined through the first analysis image set, that is, the optimal pole slot combination is obtained. And the number of pole slots of the target motor is adjusted according to the optimal pole slot combination.

[0083] In one implementation, the first analysis image set includes: an analysis image of the excitation winding induced voltage ratio generated by the target motor under different pole-slot combinations varying with the rotor position under each of the no-load condition, the armature current supply only condition, and the load condition, and a spectrum analysis image of the excitation winding induced voltage ratio.

[0084] Specifically, this embodiment first analyzes the FW induced voltage pulsation of different pole slot combinations under no-load conditions. According to Faraday's law of electromagnetic induction, FW flux pulsation will generate induced voltage pulsation in the FW. In order to quantify the impact of FW induced voltage pulsation, the FW induced voltage ratio is used. , which is defined as:

[0085] , (2);

[0086] In formula (2), is the FW induced voltage ripple value, is the resistance voltage drop of FW. In the subsequent analysis, the resistance voltage drop of FW remains constant and does not change with the change of the rotor electrical position of each slot-pole combination.

[0087] analyze Figure 5 , Figure 6 , Figure 7 , Figure 8 The results show that for 6-slot HESFMs, the 4-pole and 8-pole configurations have a relatively high no-load FW induced voltage ratio due to the dominance of the 3rd harmonic, while the 5-pole and 7-pole configurations have a relatively low no-load FW induced voltage ratio due to the dominance of the 6th harmonic. For 12-slot HESFMs, the main harmonics of the 10-pole and 14-pole configurations are the 6th, and the main harmonics of the 11-pole and 13-pole configurations are the 12th. In particular, the peak-to-peak value of the no-load FW induced voltage ratio of the 6-slot 4-pole and 6-slot 8-pole HESFMs is relatively high due to the high amplitude of the low-order harmonics; while the peak-to-peak value of the no-load FW induced voltage ratio of the 12-slot 11-pole and 12-slot 13-pole HESFMs is relatively low due to the low amplitude of the high-order harmonics.

[0088] Then, this embodiment also evaluates the FW induced voltage ripple under the condition of only armature current supply. Fig. 9 , Fig.10 , Fig.11 , Fig.12 The spectrum diagram is shown, and the results show that under this operating condition, different pole-slot combinations have a significant impact on the harmonic order of FW flux and the induced voltage pulsation.

[0089] After that, this embodiment evaluates the FW induced voltage pulsation under load conditions. Under load conditions, the FW induced voltage pulsation is composed of the no-load induced voltage component and the armature current induced voltage component, and its harmonic order depends on these two components. This embodiment analyzes the load condition, Fig.13 , Fig.14 , Fig.15 , Fig.16 The loaded FW induced voltage ratio of HESFMs with different pole-slot combinations under loaded conditions is shown, revealing the influence of loaded conditions on the induced voltage pulsation.

[0090] It is worth noting that the induced voltage ripple of the loaded FW is not always higher than that of the no-load condition, which is related to the sensitivity of magnetic saturation. Fig.17 In particular, the loaded induction field winding voltage ratio of a 6-slot 4-pole motor at different load levels is shown, which further confirms the influence of load level on the FW induced voltage ripple.

[0091] As shown in Table 2, the characteristics of the induced voltage pulsation of the DC winding of HESFMs under three different conditions analyzed in this embodiment are shown. It can be seen that whether in no-load or loaded state, the induced voltage pulsation in the excitation winding of HESFMs with odd rotor poles is generally smaller than that of HESFMs with even rotor poles; the peak-to-peak value of the induced voltage of the excitation winding of HESFMs with higher harmonic orders is lower, thus having less impact on the motor characteristics.

[0092] Table 2. Summary of DC winding induced voltage ripple characteristics in HESFMs

[0093]

[0094] In one implementation, the optimal pole-slot matching is: the difference between the number of stator slots and the number of rotor poles is 1 or 2.

[0095] Specifically, from the perspective of output torque capacity, the optimal pole-slot combination determined in this embodiment can be selected from the following combinations: the number of stator slots is one more than the number of rotor poles, the number of stator slots is one less than the number of rotor poles, the number of stator slots is two more than the number of rotor poles, and the number of stator slots is two less than the number of rotor poles. Preferably, the number of stator slots is one more than the number of rotor poles, or the number of stator slots is one less than the number of rotor poles. The combined coil base coefficient of these pole-slot combinations is high, showing better torque performance. In other words, the optimal pole-slot combination is = or ,in, is the number of stator slots, is the number of rotor poles. In order to reduce the influence of the induced voltage pulsation of the excitation winding, the pole-slot combination is preferably = The combination of the above can enhance the motor's ability to output torque, effectively reduce the peak-to-peak value of the induced voltage pulsation of the excitation winding, optimize the overall performance of the motor and improve its stability.

[0096] In one implementation, the number of rotor poles is an even number, and the number of rotor poles is less than a preset value.

[0097] Specifically, HESFMs with an odd number of rotor poles are affected by unbalanced magnetic pull, so the number of rotor poles is preferably set to an even number while satisfying the optimal pole-slot matching. It should be noted that HESFMs with a large number of rotor poles have problems such as high core loss and PM eddy current loss, especially when the motor is running at high speed. In addition, high electrical frequency will also lead to high switching losses of power devices in the control system.

[0098] In another implementation method, a mature criterion layer and solution layer can be established through a preset hierarchical analysis method, the influence weights of different factors can be determined according to different application conditions, and a trade-off and evaluation can be made between low loss and low excitation winding induced voltage pulsation, so as to explore new high-efficiency energy-saving motors with low loss and low pulsation suitable for different motor topologies.

[0099] In another implementation, the magnetic field and induced voltage characteristics of different combinations of rotor poles and stator slots can be simulated and calculated, and the trade-off and evaluation between low loss and low excitation winding induced voltage pulsation can be made through a preset evaluation algorithm to automatically select the optimal design parameters, thereby making more scientific and reasonable decisions in the design stage.

[0100] In another implementation, the FW induced voltage pulsation and its generation mechanism of different slot-pole number combinations of the target motor under no-load, three-phase armature current excitation only, and load conditions can be deeply analyzed by finite element analysis (FEA) method.

[0101] Step S400: Under different preset working conditions, obtain a second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions after global optimization or pole slot number optimization, determine the optimal layout position of the permanent magnet according to the second analysis image set, and optimize the permanent magnet position of the target motor according to the optimal layout position.

[0102] Specifically, after the global optimization is completed or the number of pole slots is optimized, in order to further weaken the induced voltage pulsation of the excitation winding of HESFMs, the present embodiment can also optimize the position of the permanent magnet of the target motor. By changing the position of the permanent magnet to suppress the induced voltage pulsation in the HESFMs, not only the induced voltage pulsation is effectively reduced, but also the stability and reliability of the motor are enhanced. In practical applications, multiple working conditions are pre-selected, and the situation of the target motor generating the induced voltage ratio of the excitation winding under different working conditions and different permanent magnet layout positions is analyzed, and the analysis results are summarized into a second analysis image set, and the permanent magnet layout position that can effectively weaken the induced voltage pulsation of the excitation winding is determined by the second analysis image set, that is, the optimal layout position is obtained. And the layout position of the permanent magnet in the target motor is determined according to the optimal layout position. In short, after the global optimization is completed, the present embodiment also provides two methods for weakening the induced voltage pulsation of the excitation winding, one method is to optimize the pole slot matching, and the other method is to optimize the position of the permanent magnet. The two methods can be used together or separately, and both methods provide new perspectives for the design and application of HESFMs.

[0103] In one implementation, the second analysis image set includes: an analysis image of the excitation winding induced voltage ratio generated by the target motor under different permanent magnet positions under each of the no-load condition and the loaded condition, which varies with the rotor position, and a spectrum analysis image of the excitation winding induced voltage ratio.

[0104] In one implementation, the optimal layout position is: placing the permanent magnet at the bottom or middle of the motor.

[0105] Specifically, in the studies before this embodiment, the analysis of HESFMs was based on a specific topological structure, that is, the permanent magnet (PM) was located at the bottom of the stator slot and equipped with an iron bridge. In fact, the position of the permanent magnet is flexible and can be arranged at the bottom, middle or top of the stator slot, and is not necessarily equipped with an iron bridge. Fig.18 The topological structures of HESFMs with four different configurations of permanent magnet positions are shown.

[0106] This embodiment compares and analyzes the induced voltage of the excitation winding of the 12-slot 10-pole HESFMs under no-load and loaded conditions at a rotation speed of 400 rpm under different configurations of permanent magnet positions. Fig.19 and Fig. 20 The variation of the excitation winding induced voltage ratio with the rotor position (electrical angle) and harmonic order under no-load conditions is shown respectively. Fig.21 and Fig. 22The corresponding data under load conditions are shown respectively. Experimental data show that placing the permanent magnet at the top of the motor will increase the amplitude of the sixth harmonic, thereby increasing the induced voltage of the excitation winding. Specifically, under no-load and loaded conditions, due to the high amplitude of the sixth harmonic, when the permanent magnet is placed at the top, the induced voltage ratio of the excitation winding is generally higher than that of HESFMs with other configurations. Placing the permanent magnet at the bottom or middle of the motor can more effectively reduce the induced voltage pulsation of the DC excitation winding than placing it at the top. Therefore, the influence of induced voltage pulsation can be effectively reduced by changing the layout position of the permanent magnet, especially by placing the permanent magnet at the bottom or middle position of the motor (specifically, it can be set at the bottom or middle of the slot).

[0107] It should be noted that the use of an iron bridge has no significant effect on the harmonic order of the induced voltage ratio of the excitation winding, that is, whether an iron bridge is equipped does not affect the harmonic order of the induced voltage ratio of the excitation winding. Under no-load and load conditions, whether it is HESFMs with permanent magnets placed at the bottom and equipped with an iron bridge, or its variants, the main harmonic order of the induced voltage is 6. Therefore, the influence of the iron bridge design on the induced voltage pulsation can be reasonably ignored in the motor design stage.

[0108] It should be noted that in terms of the excitation method of the excitation winding, whether a constant current power supply or an H-bridge converter is used, the induced voltage ripple will bring a series of challenges. When the excitation winding is excited by a constant current power supply, the induced voltage ripple may cause the actual current to decrease at certain rotor positions, thereby reducing the torque and power density, especially at high speeds. In addition, if the induced voltage ripple exceeds the compliant voltage of the power supply at high speeds, it may cause reverse current to the power supply. At the same time, the negative value of the induced voltage ripple may also trigger the reverse voltage protection mechanism of the current power supply.

[0109] The influence of induced voltage ripple is also significant when using half-H-bridge or full-H-bridge converters for excitation. In order to maintain a stable DC current in the excitation winding, the control system needs to consider the induced voltage ripple as a disturbance voltage, which increases the complexity of control. In addition, in order to balance the induced voltage, the DC bus voltage of the converter needs to be set higher, especially at high speeds, which limits the operating speed of the motor. Since the full H-bridge converter can provide a reverse output voltage, it will have more advantages than the half H-bridge converter at high speeds.

[0110] In short, the induced voltage ripple in the excitation winding not only affects the torque and speed stability of the motor, but also puts forward higher requirements on the design of the power supply and control system, and increases the power supply cost of the inverter, especially when running at high speed. The pole slot number optimization method and permanent magnet position optimization method proposed in this embodiment provide important theoretical basis and practical guidance for solving problems such as induced voltage ripple, as well as for the design and optimization of hybrid excitation motors.

[0111] In one implementation, permanent magnets of different densities or shapes may be used to distribute the permanent magnets unevenly on the rotor, for example, increasing the density of permanent magnets in certain areas of the rotor to change the distribution of the magnetic field and the characteristics of the induced voltage. In other words, this embodiment may not limit the specific arrangement position of the permanent magnets, but may suppress the induced voltage pulsation by adjusting the density, shape, and distribution of the permanent magnets.

[0112] In one implementation, the optimization objective may also be transformed into: weakening the torque ripple of HESFMs, or weakening the back-EMF harmonics of HESFMs, or weakening the cogging torque of HESFMs.

[0113] Based on the above embodiment, the present invention further provides a terminal, whose principle block diagram can be shown as follows: Fig.23 As shown. The terminal includes a processor, a memory, a network interface, and a display screen connected via a system bus. Among them, the processor of the terminal is used to provide computing and control capabilities. The memory of the terminal includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the terminal is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a motor optimization method based on pole slot matching and permanent magnet position is implemented. The display screen of the terminal can be a liquid crystal display or an electronic ink display.

[0114] Those skilled in the art will understand that Fig.23 The principle block diagram shown in the figure is only a block diagram of a partial structure related to the scheme of the present invention, and does not constitute a limitation on the terminal to which the scheme of the present invention is applied. The specific terminal may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0115] In one implementation, the terminal has one or more programs stored in its memory and is configured to be executed by one or more processors. The one or more programs include instructions for performing a motor optimization method based on pole-slot matching and permanent magnet positions.

[0116] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided by the present invention can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0117] In summary, the present invention discloses a motor optimization method, terminal and medium based on pole slot matching and permanent magnet position. By determining the target motor to be optimized, wherein the target motor is a hybrid excitation flux switching motor, which has both permanent magnets and excitation coils, and is additionally provided with an external iron bridge; under preset brushless AC control conditions, the motor parameters of the target motor are globally optimized by a preset genetic algorithm with the average electromagnetic torque maximization within one electrical cycle as the optimization goal; under preset different working conditions, the first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole slot matching after global optimization is obtained, the optimal pole slot matching is determined according to the first analysis image set, and the number of pole slots of the target motor is optimized according to the optimal pole slot matching; under preset different working conditions, the second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions after global optimization or after the number of pole slots is optimized is obtained, the optimal layout position of the permanent magnet is determined according to the second analysis image set, and the position of the permanent magnet of the target motor is optimized according to the optimal layout position. The present invention firstly globally optimizes the motor parameters of the hybrid excitation flux switching motor, and then optimizes the pole-slot matching and / or the permanent magnet position, thereby effectively suppressing the induced voltage pulsation, improving the stability and efficiency of the motor, and ultimately achieving the purpose of improving the overall performance of the motor.

[0118] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A motor optimization method based on pole-slot matching and permanent magnet position, characterized in that: The method comprises: Determining a target motor to be optimized, wherein the target motor is a hybrid excitation flux switching motor having both permanent magnets and excitation coils and additionally provided with an external iron bridge; Under the preset brushless AC control condition, taking the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal, the motor parameters of the target motor are globally optimized by a preset genetic algorithm; Under different preset working conditions, a first analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different pole slot combinations after global optimization is obtained, an optimal pole slot combination is determined according to the first analysis image set, and the number of pole slots of the target motor is optimized according to the optimal pole slot combination; Under different preset working conditions, a second analysis image set of the excitation winding induced voltage ratio generated by the target motor based on different permanent magnet positions is obtained after global optimization or pole slot number optimization, the optimal layout position of the permanent magnet is determined according to the second analysis image set, and the permanent magnet position of the target motor is optimized according to the optimal layout position.

2. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The stator part of the target motor is used to accommodate the armature winding, the excitation winding and the permanent magnet; the convex rotor is composed of an iron core and does not contain any permanent magnets and coils; the armature winding and the excitation winding both adopt concentrated non-overlapping windings; the permanent magnet adopts a tangential magnetization method and is placed at the center of each stator pole.

3. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The genetic algorithm is used to: The objective function is established in advance with the maximization of the average electromagnetic torque within one electrical cycle as the optimization goal; Randomly generate a number of individuals, wherein each individual represents a parameter setting scheme of the target motor, and the chromosome of each individual is composed of a gene set, and each gene in the gene set represents a motor parameter; Calculate the fitness value corresponding to each individual according to the objective function, and determine whether a preset termination condition is currently reached, wherein the termination condition is that a maximum number of iterations is reached or there is an individual whose fitness value reaches a preset threshold; If the termination condition is not met currently, the parent population for reproduction is selected according to the fitness value of each individual; Performing chromosome crossover recombination on individuals in the parent population to obtain a number of new individuals; Continue to execute the step of calculating the fitness value corresponding to each individual according to the objective function until the termination condition is reached, and determine the optimal parameter setting scheme according to the individual with the highest fitness value among all current individuals; The motor parameters of the target motor are globally optimized according to the optimal parameter setting scheme.

4. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The first analysis image set includes: analysis images of the excitation winding induced voltage ratio generated by the target motor under different pole-slot combinations changing with the rotor position under each of the no-load condition, the armature current supply only condition and the load condition, and a spectrum analysis image of the excitation winding induced voltage ratio.

5. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The second analysis image set includes: an analysis image of the excitation winding induced voltage ratio generated by the target motor under different permanent magnet positions under each of the no-load condition and the loaded condition, which varies with the rotor position, and a spectrum analysis image of the excitation winding induced voltage ratio.

6. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The optimal pole-slot combination is: the difference between the number of stator slots and the number of rotor poles is 1 or 2.

7. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The optimal layout position is: placing the permanent magnet at the bottom or middle of the motor.

8. The motor optimization method based on pole-slot matching and permanent magnet position according to claim 1, characterized in that: The thickness of the additional external iron bridge is 0.5mm.

9. A terminal, characterized in that: The terminal includes a memory and one or more processors; the memory stores one or more programs; the program contains instructions for executing the motor optimization method based on pole slot matching and permanent magnet position as described in any one of claims 1-8; the processor is used to execute the program.

10. A computer-readable storage medium having a plurality of instructions stored thereon, characterized in that: The instructions are suitable for being loaded and executed by a processor to implement the steps of the motor optimization method based on pole-slot matching and permanent magnet position as described in any one of claims 1-8.

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