35results about How to "Improve weak magnetic properties" patented technology

The invention discloses a variable-speed permanent-magnet alternator system and a double-port voltage stabilization control method therefor. The system comprises a permanent-magnet alternator, a PWM (Pulse Width Modulation) rectifier, a DC filtering device and a controller, wherein the controller comprises a rotor position and rotational speed detection module, a DC voltage detection module, a DC current detection module, an AC voltage detection module, an AC current detection module, a coordinate transformation module, a first regulator, a second regulator, a current limit module and a PWM generating module. The method provided by the invention comprises the following steps: acquiring the position, the rotational speed, the DC voltage and current, and the AC voltage and current of the alternator rotor; and acquiring the quadrature-axis and direct-axis currents through coordinate transformation, so as to stabilize the DC and AC voltages for setting values and achieving amplitude limit to quadrature-axis and direct-axis currents generated by a target subjected to closed-loop control and generate PWM trigger pulses to control the PWM rectifier. By adopting the invention, double-port voltage stabilization of a DC and AC output terminal is maintained when the rotational speed of the alternator changes, the cost is low and the reliability is high.

The invention provides a vehicle built-in permanent magnet synchronous motor controlling method. The method comprises steps of 1, establishing permanent magnet synchronous motor mathematic models including a voltage equation model, an electromagnetic torque equation model and a torque balance equation model; 2, designing a sliding mode surface and a sliding mode control law, so as to achieve sliding mode control of the electromagnetic torque of a motor; 3, based on the electromagnetic torque value Te, performing decomposition to obtain a quadrature-axis current iq and a direct-axis current id; 4, based on iq, id, Udc, quadrature-direct axis voltage references U'q and U'd, obtaining quadrature-direct axis current reference values i<*>[q] and i<*>[d] by decomposition; 5, decomposing i<*>[q] and i<*>[d] to obtain the quadrature-direct axis voltage references U'q and U'd; and 6, based on the U'q and U'd, obtaining two phase stationary voltages U[alpha] and U[beta] by coordinate conversion, taking the U[alpha] and U[beta] as the input, and obtaining three phase reference voltages Ua, Ub and Uc after modulating the models to drive an inverter and the motor to work. The control method can ensure stable operation of the motor under any working condition.

The invention discloses an E-shaped stator core flux switching type hybrid permanent magnet memory motor and belongs to the field of flux-adjustable permanent magnet motors. Both rotor and stator cores of the motor adopt a salient pole structure. A stator of the motor comprises six E-shaped stator cores, V-shaped aluminum-nickel-cobalt permanent magnets, tangential-magnetizing rectangular neodymium iron boron permanent magnets and a whole layer of stator yokes, wherein adjacent neodymium iron boron permanent magnets with opposite polarities are inlaid between the two adjacent E-shaped stator cores, and a three-phase concentrated winding armature winding is wound across a sandwich-shaped unit composed of the core edges of adjacent E-shaped stator units and the neodymium iron boron permanent magnets; a groove between two adjacent V-shaped aluminum-nickel-cobalt permanent magnets is used for placing a concentrated single-phase pulse winding. The E-shaped stator core flux switching type hybrid permanent magnet memory motor greatly alleviates a space conflict between electromagnetic loading in the stator cores and pulse magnet-adjustment capacity, can realize flexible online magnet adjustment and has little loss of excitation, the torque density and the force and energy expression of the motor can be improved, and the fault-tolerant fault operation ability is good.

The invention relates to a stator surface-mounted doubly salient permanent magnet motor with an auxiliary salient pole which has simple and firm structure, and constant power, wide speed-regulation operation range and higher power density; the motor comprises a stator (1) and a rotor (5), the rotor (5) is arranged at the inner part or outer part of the stator (1), the stator (1) and the rotor (5)are in a doubly salient structure, and a concentrated winding (3), a permanent magnet (2) and an auxiliary salient pole (4) are arranged on the stator (1), wherein, each concentrated winding coil of any one phase of the concentrated winding (3) is arranged in an iron core groove of the stator (1), and the coils of each a phase winding are connected serially or in parallel; the permanent magnet (2)is arranged on the salient pole of the stator (1), the outer surface of each stator tooth, facing to air gap, is mounted with two permanent magnets (2), and the polarity of two magnetic steels, belowthe same tooth, is the same, and the magnetism of the magnetic steel, below the adjacent stator tooth, is opposite.

The invention discloses a disc type motor rotor with a pole shoe composite magnetic pole structure, and relates to the field of motors. The disc type motor rotor comprises a rotor supporting disc, a hole is formed in the center of the rotor supporting disc, and a groove is formed in the surface of one side of the rotor supporting disc and used for installing a rotor core and composite magnetic poles; the rotor iron core is of an annular structure, is arranged at the bottom of the groove and is tightly attached to the rotor supporting disc, T-shaped baffles distributed in the radial direction are arranged on a surface of a side, away from the rotor supporting disc, of the rotor iron core, and the T-shaped baffles divide the rotor iron core into a plurality of fan-shaped spaces at equal intervals along the circumference; the composite magnetic poles are arranged in the fan-shaped spaces on the rotor iron core; the composite magnetic poles comprise permanent magnets and pole shoes, and the pole shoes made of composite soft magnetic materials are installed on the surface of the permanent magnet. The radians of the pole shoes on the surface of the permanent magnet can be adjusted, sinewave air gap flux density is generated, the output torque of a motor is smooth, the pole shoes can protect the permanent magnets against field loss under the action of a demagnetization field, the field weakening capacity of the motor is improved, and the motor is easy to machine and suitable for batch production.

The invention discloses a split type combined permanent magnet brushless motor for an electric vehicle. A rotor is coaxially positioned in the internal of a stator; a rectangular neodymium iron boron permanent magnet steel and two same rectangular ferrite permanent magnet steels are fixedly embedded in each pole of the rotor; the neodymium iron boron permanent magnet steels are close to air gaps and are symmetrical relative to the central line of the rotor poles; the two ferrite permanent magnet steels are close to a rotation shaft, are distributed on the two sides of the central line of the rotor poles and are symmetrical relative to the central line of the rotor poles; a magnetic conductive bridge is between the two ferrite permanent magnet steels; the permanent magnet steel on each pole is magnetized along the tangential direction of the circumference; the magnetizing directions on the same pole are the same, and the magnetizing directions on the adjacent two poles are opposite; the rare earth permanent magnet material and the non-rare-earth ferrite permanent magnet material are adopted at the same time; on the basis of ensuring the power density and the torque density of the permanent magnet motor with a small amount of rare earth, the cost of the motor is reduced by more than 50%; and in addition, the requirements on the torque and the power in the electric vehicle applications can be met on the premise of keeping the relatively high power density and the torque density.

The invention discloses a disc rotor and a disc motor. The disc rotor comprises a ring iron core which is provided with multiple sets of magnetic steel installing positions, wherein the magnetic steelinstalling positions are provided with buckle devices; magnetic steel which is installed in the magnetic steel installing positions and can be buckled in the magnetic steel installing positions by the buckle devices; a ring hoop which sleeves the outer circle of the ring iron core and is connected with the outer circumferential surface in an abutting way; and a rotor support which is provided with a ring boss which is inwardly sleeved in the inner circle of the ring iron core and connected with the inner circumferential surface in an abutting way, wherein the ring iron core is connected withthe rotor support through first screws. The ring iron core is fixed on the rotor support through the first screws and the rotor support axially limits the ring iron core so as to prevent axial displacement under the axial tension of the stator iron core. Besides, the buckle devices are arranged in the magnetic steel installing positions and the buckle devices can buckle the magnetic steel in the magnetic steel installing positions so as to prevent axial displacement of the magnetic steel.

The invention discloses a stator yoke-free axial flux permanent magnet motor comprising a stator, a first rotor and a second rotor which are coaxial. The first rotor and the second rotor are symmetrically arranged on the two sides of the stator. The first rotor and the second rotor respectively comprise a hollow annular first rotor core and a second rotor core which are used for coaxially connecting with a rotating shaft. The first rotor core and the second rotor core are alternately provided with permanent magnets and soft magnets along the circumference toward the end face of the stator. Theratio of the pole-arc coefficient of the permanent magnets to the soft magnets is greater than 1. The permanent magnets and the soft magnets on the different rotors of the two sides of the stator arearranged diagonally. According to the stator yoke-free axial flux permanent magnet motor, the flux weakening capability and the utilization ratio of the permanent magnets can be enhanced, the coggingtorque and the axial magnetic tension can be reduced and the bearing of the motor can be protected to a certain extent by using the diagonal alternating rotor structure with unequal pole-arc coefficient.

The invention discloses a Halbach array permanent magnet synchronous motor with high flux weakening property. The Halbach array permanent magnet synchronous motor structurally comprises a stator iron core, a three-phase armature winding, an air gap, a rotor iron core, a sectional Halbach array permanent magnet pole, and the like. The Halbach array permanent magnet synchronous motor has the advantages that the problem of difficulty in flux weakening in the traditional surface-mounted permanent magnet synchronous motor is solved; by additionally arranging a rotor iron core convex pole on a direct axis, the length of the air gap of the direct axis is effectively reduced, the reactance of the direct axis of the armature is increased, the flux weakening effect of the armature current is enhanced, and the irreversible demagnetizing of the permanent magnet in the demagnetizing magnetic field is avoided; the surface-mounted magnetic pole adopts the sectional Halbach array structure, so that the distribution of the air gap magnetic field is improved, the problems of overlarge torque fluctuating and the like due to the rotor convex pole are relieved, and the property of the whole motor is improved.

The invention provides a 12-slot 10-pole permanent-magnetic brushless motor. A rotor is provided with 20 slot wedges. 20 magnetic steel sheets are installed among the slot wedges. Each of the magnetic steel sheets is of a V-type embedded structure. Each V-type unit is formed by two adjacent magnetic steel sheets. 10 V-type units are uniformly distributed around the rotor. Polarity of two faces, arranged in the corresponding V-type opening, of the magnetic steel sheets is the same and each V-type opening is towards the surface of the rotor. The polarity of the opening of each V-type unit is different from that of openings of adjacent two V-type units. The thickness of each magnetic steel sheet is 3.0+ / - 0.01mm. According to the invention, steel faces can be protected; demagnetizing resisting ability of the brushless motor is improved; stable operation life of the motor is prolonged; high-speed performance of the motor is improved; flux weakening ability of the motor is effectively improved; and constant-power operation range of the motor is extended.

The invention provides a high-strength magnetic-gathering permanent-magnet rotor according to the problem of limitation of overload capacity and rotor strength of an existing built-in tangential permanent-magnet motor. The high-strength magnetic-gathering permanent-magnet rotor comprises a rotor core and a permanent magnet, wherein a plurality of permanent-magnet grooves are uniformly formed in the rotor core along a circumferential direction, the permanent-magnet grooves are arranged along a direction of a rotation shaft in a penetrating way, adaptive tangential permanent magnets are arrangedin the permanent-magnet grooves, linear grooves are formed in the rotor core at intervals along a circumferential direction, the linear grooves are arranged along the direction of the rotation shaftin a penetrating way, linear permanent magnets are arranged in the linear grooves, at least two linear grooves arranged in a straight line way and two of the linear permanent magnets are arranged between two adjacent permanent-magnet grooves. A light and high-strength alloy material is embedded to an inner side of the rotor core, the rotor weight is reduced, and the rotor strength is improved. Thehigh-strength magnetic-gathering permanent-magnet motor has the characteristics of high overload capability, high rotor strength, high power density, high modular degree and the like and is suitablefor application occasions such as an aviation permanent-magnet starting power generation system.

The invention discloses a permanent magnet motor and a compressor. The permanent magnet motor comprises a stator and a rotor. The stator comprises a stator core, a plurality of coil groups, and two motor lead groups. Each coil group comprises a plurality of coils which are coiled on stator bulging teeth. Each coil group comprises an incoming line terminal and a leading-out terminal formed by joints in the same number. Each motor lead group has a plurality of joints used to connect with the coil groups, and a motor lead of a motor control circuit. An inverter with a control algorithm provides power input for the permanent magnet motor. An effective value Um of maximum voltage between terminals, provided to the permanent magnet motor by the inverter, and no-load back EMF ke value between motor line terminals satisfy 4<=Um / ke<=56, wherein unit of Um is volt, unit of ke is volt / thousand round per minute. The permanent magnet motor can also satisfy torque output capacity of a motor in high-frequency.

The invention discloses a multi-layer rotor magnetic steel structure of a permanent magnet motor for a high-power-density new energy automobile. The structure comprises a rotor core, a plurality of magnetic steel groove groups are arranged on the rotor core at interval along the circumferential direction, each magnetic steel groove group is composed of first layer V-shaped magnetic steel grooves and second layer V-shaped magnetic steel grooves, and a first layer of magnetic steel and a second layer of magnetic steel are respectively arranged in the first layer V-shaped magnetic steel groove and the second layer V-shaped magnetic steel groove; the first layer of V-shaped magnetic steel grooves are symmetrical about the radial direction of the rotor core, and the second layer of V-shaped magnetic steel grooves are symmetrically arranged at two sides of the first layer of V-shaped magnetic steel grooves; v-shaped openings of the first-layer V-shaped magnetic steel grooves face the outer ring of the rotor core, and the extending directions of the two side grooves of the first-layer V-shaped magnetic steel grooves and the extending directions of the two side grooves of the second-layerV-shaped magnetic steel grooves are correspondingly parallel. A rotor is high in structural strength, and the permanent magnet motor manufactured by the rotor is high in power density.

The invention relates to the technical field of a driving motor, and particularly provides a weak flux control method and device and a motor. The weak flux control method comprises the steps of acquiring an output value of a q-axis voltage and a setting value of the q-axis voltage under a weak flux state; determining a compensation value of a weak flux current according to the output value and thesetting value; and compensating the weak flux current according to the compensation value. According to the control method, the weak flux effect of the motor is improved by correction and compensation on the weak flux current on the basis of an existing weak flux method, the rotational speed of the motor is further improved, the rotational speed is higher compared with existing weak flux speed rising, the driving performance of the motor is improved, and more demand scenes are met.

The invention provides a stator assembly and a hybrid excitation motor. The stator assembly comprises a stator core, a winding ring, a magnetic conduction support and an excitation winding which are coaxially arranged, wherein the winding ring, the magnetic conduction support and the excitation winding are all arranged at one end of the stator core, the magnetic conduction support sleeves the winding ring, the winding ring is made of a non-magnetic conduction material, the magnetic conduction support is made of a magnetic conduction material, a winding space is formed between the winding ringand the magnetic conduction support, and the excitation winding is arranged in the winding space. The hybrid excitation motor comprises the stator assembly. Except the hybrid excitation motor has theadvantages of good speed regulation performance, high demagnetization resistant capability, high material utilization ratio and high efficiency of a traditional hybrid excitation motor, the problem ofmagnetic saturation near to an excitation winding can be effectively reduced by the winding ring and the magnetic conduction support in the stator assembly, and the weak magnetic capability of the motor is improved.

The application provides a motor rotor, a motor, a compressor and an air conditioner. The motor rotor comprises a plurality of magnetic poles which are distributed in the circumferential direction, wherein each magnetic pole comprises a first permanent magnet (1) and a second permanent magnet (2); the first permanent magnets (1) are positioned on the d shaft of thee motor; the second permanent magnets (2) are positioned on the q shaft of the motor; the first permanent magnets (1) are magnetized in the radial direction; the second permanent magnets (2) are magnetized in the tangential direction; and the coercive force temperature coefficients [alpha] d of the first permanent magnets (1) are greater than the coercive force temperature coefficients [alpha] q of the second permanent magnets (2). According to the motor rotor, the high-frequency operation capacity of the compressor can be improved, the low-frequency energy efficiency is not influenced, and the energy efficiency ratio of thewhole machine is improved.

The invention relates to the motor technology field and especially relates to a mechanical adjustable magnet type rotation motor. The motor comprises a rotor iron core, a rotating shaft, a movable magnetic yoke and a mechanical solenoid-valve adjustable-magnetic device. A front salient pole and a rear salient pole are embedded into the rotor iron core. The movable magnetic yoke is located between the front salient pole and the rear salient pole. The mechanical solenoid-valve adjustable-magnetic device is connected to the movable magnetic yoke and makes the movable magnetic yoke axially moves along the rotating shaft. The mechanical solenoid-valve adjustable-magnetic device makes the movable magnetic yoke axially moves along the rotating shaft so that on and off of a leakage flux path which is newly added in a permanent magnetic flux are realized. Further an effective magnetic flux of a motor air gap is indirectly controlled so that the motor possesses a good adjustable flux capability and high rotating speed operation is realized. When a traditional permanent magnetism motor carries out flux weakening speed expansion, a large straight shaft is needed to carry out demagnetizing current. By using the rotation motor, the above problem is avoided. The motor is guaranteed to possess high efficiency and a high power factor. Permanent magnet steel has no demagnetization risks so that reliability of the motor is increased.

The invention discloses a multi-working mode dual-stator magnetic field modulation motor, which comprises an inner stator, a rotor, an outer stator, a permanent magnet, a first set of windings, a second set of windings; a first layer of air gaps and a second layer of air gaps They are respectively arranged between the inner stator and the rotor, and between the outer stator and the rotor; several stator teeth are arranged on the circumference of the stator, and the ends of the stator teeth have one or more small slots to form modulating teeth. The tooth end is composed of permanent magnets and modulating poles; the rotor is composed of magnetic conductors and non-magnetic conductors arranged alternately; the inner stator slot is embedded with a centralized first set of windings, and the outer stator slot is embedded with a centralized second set of windings; The purpose of the two sets of windings is determined according to the specific working mode. The multi-working mode dual-stator magnetic field modulation motor of the present invention can be applied in the field of transportation to solve the problem that the working performance of the motor cannot meet the actual needs under multiple working conditions due to complex and changeable road conditions.

The invention discloses an iron core and a disk type motor. Multiple groups of magnetic steel mounting sites are distributed on the iron core along the circumferential direction of the iron core uniformly; each group of magnetic steel mounting sites comprises a plurality of steel tanks; along the circumferential direction of the iron core, first iron core teeth are arranged between the adjacent steel tanks of the same group of the magnetic steel mounting sites; the steel tanks of the same group of magnetic steel mounting sites are used for mounting magnetic steel with the like magnetic pole; second iron core teeth are arranged between the adjacent group of magnetic steel mounting sites; and the steel tanks of the adjacent group of magnetic steel mounting sites are used for mounting magnetic steel with opposite magnetic poles. Each group of magnetic steel mounting sites comprises a plurality of steel tanks, and the same group of steel tanks are partitioned by the first iron core teeth along the circumferential direction of the iron core, so that the d-axis inductance is enhanced. When the motor performs weak magnetic control at high speed, the size of the needed current can be obviously reduced under the same voltage when the d-axis inductance of the motor is increased, or the highest weak magnetic rotating speed which the motor can reach to can be significantly increased.

The invention relates to a stator surface-mounted doubly salient permanent magnet motor with an auxiliary salient pole which has simple and firm structure, and constant power, wide speed-regulation operation range and higher power density; the motor comprises a stator (1) and a rotor (5), the rotor (5) is arranged at the inner part or outer part of the stator (1), the stator (1) and the rotor (5)are in a doubly salient structure, and a concentrated winding (3), a permanent magnet (2) and an auxiliary salient pole (4) are arranged on the stator (1), wherein, each concentrated winding coil of any one phase of the concentrated winding (3) is arranged in an iron core groove of the stator (1), and the coils of each a phase winding are connected serially or in parallel; the permanent magnet (2) is arranged on the salient pole of the stator (1), the outer surface of each stator tooth, facing to air gap, is mounted with two permanent magnets (2), and the polarity of two magnetic steels, below the same tooth, is the same, and the magnetism of the magnetic steel, below the adjacent stator tooth, is opposite.

The invention discloses a stator permanent magnet type double-rotor magnetic field modulation motor and a design method thereof. The stator permanent magnet type double-rotor magnetic field modulationmotor comprises a stator, an inner rotor and an outer rotor. The stator is arranged between the two rotors. Permanent magnets are embedded in the yoke part of the stator in the radial manner. The magnetizing direction of the permanent magnets is tangential to the circumference, and the N poles and the S poles of the permanent magnets are alternately arranged. The difference between the positionsof the inner rotor and the outer rotor is half of the polar distance of the two rotors, while the rotating directions and the rotating speeds of the two rotors are the same. The armature winding of the motor adopts the concentrated winding mode. According to the invention, two motors with double salient pole structures are combined, and the magnetic chains of the same phase coil are complementary.The single-coil magnetic chain of the motor is unipolar, and the magnetic chain of the synthetic winding is bipolar. The structure of the motor has the magnetic field modulation effect, so that the motor has higher counter electromotive force and torque performance compared with a conventional salient pole structure motor. After the armature is loaded, the generated armature magnetic field does not pass through the permanent magnet. Therefore, the permanent magnet is prevented from demagnetizing due to over-large current. The rotors of the motor are formed by laminating silicon steel sheets with salient pole structures only, so that the good robustness is achieved.

The invention discloses a permanent magnet fault-tolerant motor based on an alternate tooth winding and an unequal stator tooth pitch. The stator has Ns / 3 fault-tolerant teeth and 2Ns / 3 armature teeth. The Ns / 3 fault-tolerant teeth are uniformly distributed along the inner circumference or the outer circumference of the stator. Two armature teeth are uniformly arranged between two adjacent fault-tolerant teeth and comprise an armature tooth 1 and an armature tooth 2. A large tooth slot is formed between the armature tooth 1 and the armature tooth 2. A small tooth slot is formed between each fault-tolerant tooth and the adjacent armature teeth 1 and 2. The volume of the large tooth slot is larger than the volume of the small tooth slot. An armature coil is wound around each armature tooth.The power direction of the armature coil on the armature tooth 1 is opposite to the power direction of the armature coil on the armature tooth 2. For a fractional slot motor with a high winding factorof Ns'=2p'+ / -1, by using a combination of the alternate tooth winding and the unequal stator tooth pitch, phase-to-phase isolation is achieved, thereby improving the fault tolerance of the motor, andincreasing the self-inductance in each phase so as to improve the short-circuit current suppression capability and weak magnetic capability.

The invention discloses an optimal field weakening control method based on the safety of a spring electric rudder system. The method comprises detecting current motor speed and load torque, obtainingthe output torque at the current speed, Current limit, d-axis inductance component and q-axis inductance component, defining a weak magnetic index J, giving the optimal weak magnetic control index based on rotational speed, output torque and load torque, calculating the J value of d-axis current component under different values, selecting the maximum value maxJ of J value, and taking the d-axis current component and q-axis current component corresponding to the value as the control output under the current rotational speed. Aiming at the characteristics of tactical missile, such as no reuse, fast maneuver, complex working condition and short endurance time under the same working condition, the invention fully utilizes the weak magnetic rising speed capability of the missile electric actuator under the condition of surplus power, designs the optimal distribution strategy of the straight axis current and the numerical calculation scheme, thereby improving the weak magnetic performance ofthe missile electric actuator system.

The invention discloses a high-performance rotor based on an electric transmission system, relates to the technical field of high-performance rotors, and solves the technical problems that an existing motor is large in static braking torque, poor in rotor high-speed performance and poor in assembly manufacturability, the eddy-current loss generated by the rotor itself is high, additional torque generated by the harmonic magnetic field is relatively large, and electromagnetic vibration and noise have influence on the system at same time. The high-performance rotor comprises a rotating shaft, rotor baffles and rotor cores, wherein after the rotating shaft is sleeved with a plurality of sections of rotor cores, the two ends of the rotor cores are fixed through the rotor baffles respectively, the rotor cores are silicon steel sheets of an annular structure, magnetic steel grooves are formed in the ring surface at equal intervals, and permanent magnets are arranged in the magnetic steel grooves. By optimizing the structural performance parameters of the high-speed driving motor rotor for the electric transmission system, the cogging torque and pulsation of the whole electric system are reduced, and the performance of the whole system is improved.

The invention relates to the technical field of drive motors, and specifically provides a motor field weakening control method, device and motor. A field weakening control method, comprising: obtaining an output value of the q-axis voltage and a set value of the q-axis voltage in a field-weakening state; determining a compensation value of a field-weakening current according to the output value and the set value; The value compensates for the field weakening current. The control method of the present invention improves the field weakening effect of the motor by correcting and compensating the field weakening current on the basis of the existing field weakening method, and further increases the motor speed. performance to meet more demand scenarios.

The invention discloses a Halbach array permanent magnet synchronous motor with high flux weakening property. The Halbach array permanent magnet synchronous motor structurally comprises a stator iron core, a three-phase armature winding, an air gap, a rotor iron core, a sectional Halbach array permanent magnet pole, and the like. The Halbach array permanent magnet synchronous motor has the advantages that the problem of difficulty in flux weakening in the traditional surface-mounted permanent magnet synchronous motor is solved; by additionally arranging a rotor iron core convex pole on a direct axis, the length of the air gap of the direct axis is effectively reduced, the reactance of the direct axis of the armature is increased, the flux weakening effect of the armature current is enhanced, and the irreversible demagnetizing of the permanent magnet in the demagnetizing magnetic field is avoided; the surface-mounted magnetic pole adopts the sectional Halbach array structure, so that the distribution of the air gap magnetic field is improved, the problems of overlarge torque fluctuating and the like due to the rotor convex pole are relieved, and the property of the whole motor is improved.

The invention discloses a magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor. The motor comprises a stator and a rotor 6; the rotor of the motor comprises a rotor core, inner-layer magnets, outer-layer magnets and magnetic steel slots. And the inner-layer magnets and the outer-layer magnets, forming U-shaped structures, are distributed at the rotorcore part; each group of magnets comprises four magnets, wherein the four magnets include two radial magnets and tangential magnets; a magnetic bridge used for enhancing the mechanical strength of therotor is arranged between two adjacent magnets in each group of magnets; and with the width of the magnetic bridges properly set, the mechanical strength of the rotor of the motor can be ensured, andthe motor does not generate large magnetic flux leakage. Whether the magnetic bridges are located between the magnets or between the magnets and the outer circle of the rotor, the width of the magnetic bridges in the outer-layer magnets is greater than the width of the magnetic bridges in the inner-layer magnets. According to the magnetic steel built-in double-U-shaped fractional slot concentrated winding permanent magnet motor of the invention, the number of the layers of the built-in magnets is increased, and therefore, the reluctance torque of the motor is increased; and the segmented rotor is adopted, the pulsating torque and rotor eddy current loss of the motor are reduced.

The invention discloses an optimal field-weakening control method based on the safety of the elastic electric rudder system, which detects the current speed and load torque of the motor, and obtains the output torque, current limit value, d-axis inductance component and q-axis inductance component at the current speed , define the field weakening index J, give the optimal field weakening control index based on the speed, output torque, and load torque, calculate the J value of the d-axis current component at different values, select the maximum value maxJ of the J value, and convert this value to The corresponding d-axis current component and q-axis current component are used as the control output at the current speed. The invention aims at the characteristics of tactical missiles that do not need to be reused, fast maneuvering, complicated working conditions, and short battery life under the same working conditions, and fully utilizes the weak magnetic speed-up ability of the electric steering gear for missiles under the condition of power surplus, and designs the direct-axis current The optimal allocation strategy and numerical calculation scheme are used to improve the magnetic weakening performance of the elastic electric rudder system.