391results about How to "Small pulsation" patented technology

The invention discloses a control method of a four-phase permanent magnet fault-tolerant motor. In the method, a control mode can be automatically decided according to the diagnosed situation of a system failure; when the system is at a normal state, an SVPWM control is adopted; when the system has a phase-lacking failure, a fault-tolerant torque control is adopted; different fault-tolerant control proposals are adopted according to different types of phase-lacking failures. The control method realizes that the four-phase permanent magnet fault-tolerant motor can operate with high performance under the normal condition and the phase-lacking condition, overcomes the deficiency that the stable performance of the system when in normal working is reduced in the traditional fault-tolerant control system which adopts current for regulating PWM for realizing current tracing for the convenience of fault-tolerant control, establishes a mathematical model of the four-phase permanent magnet fault-tolerant motor under a rotating coordinate system, successfully applies an SVPWM strategy to the four-phase permanent magnet fault-tolerant motor and enhances the dynamic and static performances and reliability of the control system of the four-phase permanent magnet fault-tolerant motor.

The invention discloses a novel dead-zone effect compensation method of an AC servo inverter. The traditional method is not ideal enough to realize accurate dead-zone compensation, and thus a novel online compensation algorithm is provided aiming at the dead-zone effect of the inverter. The novel online compensation algorithm mainly comprises the four steps of: determining generation of a dead zone of the inverter; determining the relationship between the output voltage of the inverter and the actual reference voltage; determining an error voltage; and providing online compensation. The novel online compensation algorithm can save unnecessary power-on and power-off steps of a switching device, is free from any extra hardware circuit and off-line experiment measurement, has the characteristics of simpleness in implementation, low output waveform harmonic content and the like, well solves the output current pulse of a system at low frequency and effectively eliminates the zero-current clamping phenomenon.

The invention aims to disclose a photovoltaic grid-connected inverter for active energy decoupling, which comprises a first flyback converter, a second flyback converter, a voltage regulating converter, an output filter circuit and an inverter circuit. The decoupling of the output power of the photovoltaic grid-connected inverter and the output power of a solar photovoltaic array is realized, pulsation of the output power of the solar photovoltaic array is greatly reduced, the fluctuation loss caused by maximum power point tracking (MPPT) is reduced, and the conversion efficiency of the photovoltaic array is improved; only a non-electrolyte capacitor with small capacity and high reliability is adopted, the defects that the service life of the photovoltaic grid-connected inverter is shortened and the reliability is reduced caused by adopting an electrolytic capacitor are overcome, the service life and the reliability of the photovoltaic grid-connected inverter are improved; and the peak power of a transformer in the flyback converter is reduced, the volume of the transformer is reduced, the loss is effectively reduced, and the conversion efficiency is improved, so that the aim of the invention is realized.

The invention relates to a direct torque control system of a permanent-magnet synchronous motor. According to the control system, an extended kalman filter (EKF) observer is adopted for stator magnetic linkage and rotation speed estimation, according to a mathematical model of the permanent-magnet synchronous motor, the state variable x of the system equals to [Psi alpha, Psi beta, Omega gamma, Theta gamma] T, the input variable mu equals to [mu alpha, mu beta] T, the output variable y equals to [Iota alpha, Iota beta ] T, and state equations and output equations (11) of the system are obtained. The motor rotating speed is used as the input of an automatic data rate changer (ADRC) speed controller, the measurement value Te of the electromagnetic torque is calculated through the obtained stator magnetic linkage, in addition, the measurement value Te and electromagnetic torque given signals are compared, comparison results are used as the input of a space voltage vector pulse generator, and the output of the space voltage vector pulse generator is connected with a voltage source inverter of the permanent-magnet synchronous motor. The direct torque control system has the advantages of good dynamic performance, better stability performance, high robustness and high anti-interference capability.

The invention discloses a double-flexible-grinding-head magnetorheological polishing device. In the device, a vertical gantry of a bed body and an X-axis are both fixed on a horizontal base; a worktable is fixed on a sliding block of the X-axis; a Y-axis is fixed on a horizontal beam of the vertical gantry; and a first Z-axis and a second Z-axis are arrangedon the Y-axis in parallel. A large flexible grinding head is installed on the first Z-axis; and a small flexible grinding head is arranged on the second Z-axis. A high-flow circulation system connected with the large flexible grinding head and a low-flow circulation system connected with the small flexible grinding head are arranged on a trolley. A control cabinet is arranged at the rear part of the vertical gantry; and a circulation system cabinet and a cleaning system are arranged at the side surface of the vertical gantry. The double-flexible-grinding-head magnetorheological polishing device provided by the invention has the advantages of high accuracy, high rigidness, high stability and high dynamic property. The double-flexible-grinding-head magnetorheological polishing device not only can be used for processing of large-caliber phase elements, but also can be used for high-accuracy processing of large-caliber planar optical elements within the range of full caliber. The optimal matching of the processing efficiency and the processing accuracy can be realized.

The invention discloses a direct torque control method for a six-phase synchronous motor with zero-sequence current self-correction. The direct torque control method for the six-phase synchronous motor with the zero-sequence current self-correction comprises firstly, performing voltage vector reconstruction based on an idea that a zero-sequence current is equal to zero and accordingly proposing an idea DTC (Direct Torque Control); secondly, performing discrete compensation on the actual voltage vector acting time based on the dead-time compensation principle; finally, continuously compensating the voltage vector acting time through a PI adjuster and achieving a purpose that the zero-sequence current is equal to zero. The direct torque control method for the six-phase synchronous motor with the zero-sequence current self-correction solves the problem of eliminating low-order harmonic currents in a six-phase symmetrical winding permanent magnet motor DTC system of a torque and magnetic flux linkage double-hysteresis-loop structure.

The invention discloses a permanent magnet switched reluctance motor employing a distributed winding. The motor comprises a stator and a rotor sleeved inside the stator, wherein the stator and the rotor have an annular salient pole structure; the surface of a stator inner ring is provided with uniformly distributed stator teeth; the surface of a rotor outer ring is provided with uniformly distributed rotor teeth; a gap is formed between mutually sleeved stator core and rotor core; a permanent magnet is embedded in a stator core yoke; the stator adopts a three-phase armature winding in a distributed structure; only one winding coil is arranged between adjacent stator tooth grooves; coils passing through two stator grooves are connected to form a one-phase winding; the three-phase windings are mutually induced and coupled; during work, two-phase windings are excited and electrified at any moment; and the output torque of interacted armature winding and permanent magnet is greater than independent excitation output torque of the armature winding. The invention solves the problem that the conventional switched reluctance motor winding has low utilization rate and low motor power density. The motor can be used as an electric motor and a generator.

An U-shaped stator hybrid-excitation switch reluctance machine belongs to the field of an electrical machine. The U-shaped stator hybrid-excitation switch reluctance machine comprises a rotor and a plurality of U-shaped stator blocks arranged at the circumference of the rotor, the outer side of rotor teeth of the rotor is shaped as outer arc, the inner side of stator teeth of the U-shaped stator blocks is shaped as inner arc, a gap is arranged between the outer arc of the rotor teeth and the inner arc of the stator teeth, the plurality of U-shaped stator blocks form a modular stator, excitation windings are wound around the two stator teeth of each U-shaped stator block, a permanent magnet is arranged at the inner side of each U-shaped stator block, and the magnetizing direction of the permanent magnet is magnetized tangentially. When the phase number of the electrical machine is m phases, the number rate of the stator teeth to the rotor teeth of the electrical machine is 2m to (2m-1), for example, when the phase number of the electrical machine is three phases, the electrical machine is structurized with three phase 6 / 5 and three phase 12 / 10. In the U-shaped stator hybrid-excitation switch reluctance machine, the stator is the modular stator, modular production is promoted, interphase magnetic paths are not coupled and completely separated, and meanwhile, the electrical machine has the advantages of high output, simplicity in structure, high fault-tolerance capability and high reliability, is easy to maintain, and is convenient to control.

An oil pump system for a vehicle includes: a vane pump having a plurality of vanes which respectively project retractably from a plurality of vane accommodating grooves provided in a rotor so as to be brought into sliding contact with a cam surface, the vane pump being adapted to supply a hydraulic fluid to an automatic transmission; an electric power-driven oil pump for assisting the hydraulic pressure of the hydraulic fluid during an idling stop of the automobile; and an ECU for controlling its operation. During an idling stop, the hydraulic fluid is fed to the automatic transmission by the operation of the electric power-driven oil pump to assist the hydraulic pressure, while the hydraulic fluid is fed with pressure also to the vane accommodating grooves to press the vanes against the cam surface.

The invention provides a rotary compressor, comprising a compression component and a motor component which are arranged in a shell, wherein the compression component is arranged at the lower part of the shell; the motor component is arranged at the upper part of the shell; the compression component comprises an air cylinder, a piston arranged in the air cylinder and a slip sheet; a long bearing and a short bearing which are used for supporting an eccentric crankshaft are arranged on the air cylinder; the short bearing is used for dividing the inner space of shell into a low-pressure cavity atthe upper part and a high-pressure cavity at the lower part; the short bearing is provided with an upper oil pool, and an oil storage cavity is arranged at the lower end of the short bearing; the oilstorage cavity is communicated with the lubricant channel of the eccentric crankshaft; one end of an oil conduit is communicated with the upper oil pool and the other end of the oil conduit is communicated with the oil storage cavity; an oil conducting cover is arranged at the lower end of the short bearing; and the oil conducting cover, the lower end of the short bearing and the eccentric crankshaft form an oil storage chamber. The rotary compressor is simple and reasonable in structure, flexible in operation, good in lubrication performance, good in oil-gas separation effect, low in oil seal amount and high in safety degree.

The invention relates to a micro-size permanent-magnet single-phase synchronous motor which comprises a stator and a permanent-magnet rotor which are same in pole number, wherein an AC (Alternating Current) power supply supplies electricity to the stator through the switch of a control circuit; an air gap is narrowed along a same peripheral direction under each pole so that the axial lines of the poles of the permanent-magnet rotor deflect an acute angle in a free state by taking the axial line of one closest pole of the stator as a reference; a linear magnetic position sensor is arranged on the peripheral preset position of the permanent-magnet rotor to detect the polarity and the position of the permanent-magnet rotor; the control circuit determines the axial direction of the permanent-magnet flux of various poles of the permanent-magnet rotor through the output of the linear magnetic position sensor by taking the peripheral preset position as the reference; and the control circuit detects the polarity of voltage which is supplied by the AC power supply to the stator to determine the axial directions of main fluxes generated at all the poles and control the half-waves of the AC power supply one by one according to a rotation direction set for the permanent-magnet rotor. The micro-size permanent-magnet single-phase synchronous motor disclosed by the invention can start and operate according to the preset rotation direction and is good in property and simple and reliable in control structure.

The invention relates to a device and a method for direct torque control of a permanent magnet synchronous motor, belonging to the technical field of alternating current motor transmission. The device comprises the permanent magnet synchronous motor, a signal detecting circuit, a processor and an inverter. A current signal and a direct current bus voltage signal of the permanent magnet synchronous motor are respectively output to the signal detecting circuit which transmits the signals to the processor for processing so as to obtain a switch signal which is transmitted to the inverter for controlling the motor. According to a stator flux linkage amplitude error and an electromagnetic torque error, the device and the method respectively estimate a reference voltage vector in a stator rotating coordinate system, then convert the reference voltage vector into a stator biphase static coordinate system, and finally utilize a space vector modulation method to generate the switch signal for the inverter so as to control the permanent magnet synchronous motor. The device and the method adopt the space vector modulation method and substitute a proportional controller for a conventional hysteresis comparator so as to effectively reduce the pulsating movement of flux linkage and torque. The method adopted for voltage vector estimation is simple so that the structure of the control system can be simplified and easily realized.

A permanent-magnetic type rotary electric machine includes a stator having teeth that are arranged in the peripheral direction thereof and around which armature windings of plural phases are wound, and a rotor having plural permanent magnets arranged so that the poles of the permanent magnets are alternately different in the peripheral direction thereof, higher harmonic waves being contained in a no-load induced voltage waveform. A (6p−1)-th higher harmonic wave and a (6p−1)-th higher harmonic wave (p represents a positive integer) when an electrical angle of 360° is set as a fundamental wave in the no-load induced voltage waveform are made substantially coincident with each other in amplitude and phase.

The invention discloses a high-pressure continuous dense-phase biomass powder conveying device with the height of a delivery outlet adjustable, which comprises a storage silo, at least two feeding silos and a delivery silo. The principle is that the two transitional feeding silos are arranged between the storage silo and the delivery silo, are respectively provided different air ducts communicated with a main air pipeline and can control the interactive and continual feeding to the delivery silo according to the time sequence through changing the pressure difference between the two feeding silos, so that the level in the delivery silo is maintained no lower than the low level, thereby realizing the continuous and stable conveying of biomass powder to gasification equipment. The device is mainly applied in the biomass powder pressurization and gasification plant and the continuous combustion device of the biomass powder, no blockage can occur to the conveying process, and the biomass powder is conveyed continuously, smoothly and uniformly with low pulsation. Therefore, the conveying device satisfies the requirements for pressurization and gasification of the biomass powder.

A braking torque closed-loop control system and method for a switch reluctance motor. The closed-loop control system comprises a torque regulator, a mode selector, a current regulator, an angle optimization controller and a torque estimator. On the basis of the rotating speed of the motor, the mode selector implements a phase current soft chopper control in a low rotating speed region and an angle position control in a high rotating speed region. The current regulator performs soft chopper hysteretic current regulation. The angle optimization controller optimizes a turn-on angle and a turn-off angle of a power converter master switch to reduce torque pulsation and improve braking energy feedback efficiency. The torque estimator conducts an on-line estimation of an actual braking torque estimated value of the motor based on an actual phase voltage and current of the motor to achieve braking torque signal feedback.

The invention discloses a charging and discharging control system and a charging and discharging control method of a flywheel battery. The system comprises a three-phase uncontrollable rectifying circuit, an energy storage filter capacitor, an insulated gate bipolar translator (IGBT) power conversion circuit, a zero passage detection circuit, a voltage detection circuit, a current detection circuit, a direct current voltage detection and overvoltage protection circuit, a sampling and filtering overcurrent protection circuit, a displacement sampling circuit, a temperature sampling circuit, a digital signal processor controller, an energy storage inductor, a three-phase linked switch and a rotary transformer signal processing circuit, wherein the energy storage inductor is connected between the output end of each phase on the alternating current side of the IGBT power conversion circuit and the input end of a flywheel motor; the three-phase linked switch is connected in parallel with the energy storage inductor respectively; and the rotary transformer signal processing circuit is connected between the signal output end of a rotary transformer of the flywheel motor and the quadrature encoder pulse (QEP) port of the DSP controller. In the method, charging and discharging control of a flywheel battery is realized based on the system. The system has stable output direct current voltage, small high-frequency ripple, quick dynamic response, and is particularly suitable for quick charging and quick discharging working conditions; and the power factor and efficiency of the system are improved greatly.

The invention provides a linear compressor. The linear compressor comprises a cylinder, a discharge valve, a spring combination body, and a discahrge cover. The cylinder forms a compression space for a refrigerant; a piston which moves along an axial direction in a reciprocating manner and is inserted into the cylinder. The discharge valve is arranged on one side of the cylinder and selectively discharge the coolant in the compressed space of the cylinder. The spring combination body is combined with the discharge valve. The discharge cover has the spring combination body and has a discharge space for the folow of the coolant discharged by the discharge valve. The discharge valve comprises a plurality of covers which are stacked along an axial direction.

The invention discloses a three-mode frequency conversion soft switching control method of a four-tube Buck-Boost converter and belongs to the field of direct current-direct current converters of electric energy conversion devices. The method is characterized in that a minimum value of the inductive current is controlled to be unchanged by changing the switching frequency so that the converter realizes soft switching in a full-load range. A double-closed-loop control strategy combining a voltage outer loop and a current inner loop is adopted for PWM modulation, PWM of a main power tube of theconverter is adjusted within a wide input voltage range, a purpose of adjusting a duty ratio of a Buck unit and a Boost unit is achieved, and therefore output voltage is controlled. A three-mode control method is adopted, and a working mode of a main circuit is selected by sampling and comparing input and output voltages. The method is advantaged in that wide-voltage-range input adaptive to the converter is realized, and soft switching is realized in a full-load range by combining minimum inductive current control and frequency conversion control, so switching loss of the converter is greatlyreduced.

The invention discloses a fault tolerance control method based on an asymmetric double three-phase permanent magnet synchronous motor uniform model. The objects of the invention are to establish an asymmetric double three-phase permanent magnet synchronous motor uniform model, to realize the decoupling control of the asymmetric double three-phase permanent magnet synchronous motor based on the uniform model and to improve the redundancy of the system. Aiming for asymmetry of the double three-phase permanent magnet synchronous motor under various faulted conditions and the condition that traditional coordinate transformation cannot realize decoupling control, the fault tolerance control method comprises steps of establishing a double three-phase permanent magnet synchronous motor uniform model under various faulted conditions, analyzing a coupling relation of a voltage equation in a d-q subplane, putting forward two times of rotation transformation to realize the decoupling of the d-q subplane, and putting forward the fault tolerance control method having minimum stator copper consumption or minimum stator current. The invention can effectively reduce the electromagnetic torque pulsation when the double-three-phase permanent magnet synchronous motor is in phase-deficient operation, and can realize the magnetic field directive decoupling control in the phase-deficient operation.

The invention is a model predictive control method of an embedded permanent magnet synchronous motor. The method includes the following steps: S1, establishing a discrete mathematical model of an embedded permanent magnet synchronous motor; S2, optimizing a model predictive control value function, calculating the d-axis and q-axis components of a given deadbeat voltage vector, substituting the d-axis and q-axis components ud and uq of seven basic voltage vectors into the value function, and selecting a voltage vector minimizing the value function g as a first optimal voltage vector Vopt1 for output; S3, optimizing the design of a dual-vector model predictive controller, carrying out voltage vector selection again on the basis of Vopt1 to determine a second optimal voltage vector Vopt2, andselecting a voltage vector Vj minimizing the value function g as a second optimal voltage vector Vopt2 through the value function; and S4, generating and sampling a three-phase stator current. The method can be applied to an embedded permanent magnet synchronous motor to suppress the stator current ripple.

The objective of the present invention is, in a permanent magnet motor using a ferrite magnet, to maximize torque due to the permanent magnet and torque due to the reluctance torque while minimizing the torque ripple ratio. A P-pole-implanted permanent magnet rotator containing a ferrite magnet in a laminated silicon steel sheet, wherein the permanent magnet motor is characterized in disposing, at one pole, a U-shaped permanent magnet comprising three parts, and, at the outer periphery of the U-shaped magnet, one outer-periphery permanent magnet disposed longitudinally in the peripheral direction, to generate permanent magnet torque, and also being provided with: at one pole, the permanent magnet rotator configured to generate reluctance torque using two salient poles formed between the U-shaped permanent magnet and the outer-periphery permanent magnet, and one central salient pole formed between the adjacent poles; and a stator comprising an M-phase stator winding that is a distributed winding, and a stator core having Ns slots, the ratio of Ns / P / M being a common fraction, and when the width of the center salient pole is set to [tau]cp and the slot pitch of the stator core is set to [tau]s, [tau]cp being smaller than [tau]s.

The invention relates to a biaxial harmonic gear pump, comprising a transmission shaft (1), a mandrel (2), a flexible gear (3), a rigid gear (4), left and right lateral plates (5 and 6), a sealing block (13), a rigid gear tumbler (10), a pin (11), a roller (15), a support arm (16), a shaft end cover (20), a pump body (14) and a pump cover (19), wherein the transmission shaft (1) is sleeved at the left end of the mandrel (2) and can rotate around the mandrel (2); the flexible gear (3) is a thin-wall flexible outer gear; the rigid gear (4) is a rigid inner gear, and the flexible gear (3) and the rigid gear (4) are concentric and equal in tooth width; the support arm (16) is fixed on the mandrel (2); the sealing block (13), the left and right lateral plates (5 and 6), the flexible gear (3) and the rigid gear (4) form two symmetrical oil absorption cavities (a) and two symmetrical oil pressure cavities (b). Therefore, pressure oil acts on the transmission shaft and the radial force on the bearing is balanced; the service life of the pump is prolonged; the problem of radial force of the traditional gear pump is effectively solved.

The invention discloses a suspension rotor equivalent disturbance current compensation control device for a bearing-free permanent magnet synchronous motor. The control device is characterized in that: a generalized suspension system consists of an expended voltage controlled inverter, a current controller, a Clark transformer, a motor and a displacement sensor; observation and compensation algorithms are formed by connecting disturbance acceleration observers, equivalent disturbance current transforming links, composite radial displacement feedback, main controllers and composite controllers in sequence; two paths of observation and compensation algorithms are connected in series in front of the generalized suspension system and form a close-loop structure; and the control device is used for controlling a motor suspension system in a displacement ring of a bearing-free permanent magnet synchronous motor. The control device carries out the close-loop control on the displacement ring of the bearing-free permanent magnet motor suspension system of the consequent pole, and suppresses disturbance acting on the suspension system in a control mode of feedforward compensation. The control device observes disturbance acceleration generated by the suspension rotor of the motor because of disturbance effect through the disturbance observation algorithm in real time, and the algorithm does not dependent on a mathematical model of the suspension system and does not need to acquire specific forms of the disturbance in advance, so that the control device has wider adaptive range.

The invention discloses a low-power four-phase switched reluctance generator power converter. A main circuit of the converter consists of a separately excited asymmetric half-bridge four-phase winding power converter main circuit and a Zeta chopper circuit which are in end-to-end connection in parallel; a generation output side of the separately excited asymmetric half-bridge four-phase winding power converter main circuit is in parallel connection with an input side of the Zeta chopper circuit; and an output side of the Zeta chopper circuit is in parallel connection with an excitation input side of the separately excited asymmetric half-bridge four-phase winding power converter main circuit. The converter has a simple structure, two windings can work at the same time, so that power density is increased, the voltage and current pulsation is reduced, the wide adjustable range of the exciting voltage is beneficial to the control of the maximum power output, and the converter can be used in the fields of small-scale wind power generation and direct current power supply.

The invention discloses a brushless direct current motor rotor, which comprises a rotor core, a revolving shaft and a permanent magnet, wherein the rotor core is formed by laminating and integrally connecting punched sheets; the revolving shaft is fixedly connected with the rotor core; even T-shaped wedges are uniformly distributed on the outer surface of the rotor core; a slot is formed between adjacent T-shaped wedges; the permanent magnet is correspondingly embedded into the slot and is a double-arc-shaped corrugated body of which the middle is thick and the two ends are thin; the middle part of the permanent magnet and the outer circle part of each T-shaped wedge are positioned on the rotation circumference of the rotor core; and a downward-concave part is formed between the middle part of the permanent magnet and an adjacent T-shaped wedge, so that non-uniform air gaps are formed between the rotor and a stator. The invention has the advantages that: main pole waveforms of a magnetic field are distributed in the form of sine waves; and the motor rotor has the advantages of small induced electromotive force harmonic wave, low noise, small pulsation and high efficiency.

A multiphase claw-pole type electric rotary machine has two or more phases-stator units. The stator units are arranged phase by phase in an axial direction of the electric rotary machine. Each phase stator unit comprises a pair of complementary-opposed claw pole core blocks and a ring-shaped stator coil sandwiched therebetween. The stator units have structures rotatably adjustable independent of each other in their phase positional relations while maintaining concentricity of them after assembly of the rotary machine before being secured.

The invention discloses a power source of an elevator contracting brake. The power source comprises a direct-current power source and a chopper circuit. The elevator contracting brake comprises a contracting brake coil, an input end of the chopper circuit is connected with the direct-current power source, and an output end of the chopper circuit is connected with the contracting brake coil. The chopper circuit comprises a microcontroller, a switching tube, a freewheeling diode, an output current detection circuit, an output voltage detection circuit and a switching tube drive circuit. The switching tube is serially connected in a main circuit of the chopper circuit, and a control electrode of the switching tube is connected with a drive signal output end of the switching tube drive circuit. An output end of the output current detection circuit and an output end of the output voltage detection circuit are respectively connected with the microcontroller, and a control signal output end of the microcontroller is connected with a control end of the switching tube drive circuit. An anode of the freewheeling diode is connected with a cathode of the output end of the chopper circuit, and a cathode of the freewheeling diode is connected with an anode of the output end of the chopper circuit. The power source has advantages of small device quantity, low cost, reduction of direct-current voltage pulsation, few circuit faults and low later maintenance cost.