2647 results about "Permanent magnet synchronous generator" patented technology

A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference Δθ between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position. A high-efficiency motor drive unit with improved maintainability of rotary sensor and improved accuracy of sensing the magnet pole position of a permanent magnet synchronous motor that accelerates and decelerates very quickly in a wide range of speed is realized.

A high speed centrifugal compressor for compressing fluids includes a permanent magnet synchronous motor (PMSM) having a hollow shaft, the being supported on its ends by ball bearing comprising supports. A permanent magnet core is embedded inside the shaft. A stator with a winding is located radially outward of the shaft. The PMSM includes a rotor including at least one impeller secured to the shaft or integrated with the shaft as a single piece. The rotor is a high rigidity rotor providing a bending mode speed of at least 100,000 RPM which advantageously permits implementation of relatively low-cost ball bearing comprising supports.

A method for identifying an initial position of a rotor of a permanent magnet synchronous motor of a non-position sensor belongs to the motor control field, and aims at solving the problems of the traditional method for identifying the initial position of magnetic poles of the rotor such as position change of the rotor, low identification precision or complex algorithm. The method comprises the following steps: maintaining the rotor under a static state during the identification process of the initial position of the rotor, injecting a high-frequency voltage signal to a stator winding, carrying out rotational coordinate conversion on three-phase stator current, and acquiring position information of the magnetic poles of the rotor by current components at q axis to obtain an initial judgment value of the magnetic pole position of the rotor; and then injecting two impulse voltage vectors in opposite directions to the stator winding, judging the polarity of the magnetic poles by comparing size of current components at d axis, and correcting the initial judgment value of the magnetic pole position obtained formerly by the judged polarity information of the magnetic poles to finally obtain an initial position angle of the rotor.

The invention discloses a parameter offline identification method for a permanent magnet synchronous motor under the condition of rest, belonging to the field of motor control and solving the problems of rotor external locking, overlong identification time, poor result consistency, poor practicability and the like of the existing parameter offline identification method for the permanent magnet synchronous motor under the condition of rest. The parameter offline identification method comprises the steps of: always keeping a rotor in a rest state, injecting a high-frequency voltage signal in a straight axis of a rotor winding, detecting a three-phase stator current and transforming into two-phase rotational coordinates, carrying out discrete Fourier transform on the current to obtain a straight axis high-frequency current amplitude so as to obtain a straight-axis inductance value through calculation; then injecting a high-frequency voltage signal in a quadrature axis of the stator winding, obtaining a quadrature axis inductance value by using the same method; and then introducing a linearly increasing current into the straight axis of the stator winding so as to obtain a voltage generating a corresponding current through reconstruction of a voltage of an inverter, calculating and fitting a straight slope by using a least square method by using a straight axis voltage value as a longitudinal coordinate and a straight axis current value as a transverse coordinate, and finally obtaining a slope value, wherein the slope value is a stator resistance value.

The invention relates to a current predictive control method of a permanent magnet synchronous motor, which belongs to the electric control field. The dynamic response speed and the control accuracy for the stator current control of the permanent magnet synchronous motor are improved through stator current prediction and deadbeat control, and the system delaying is compensated, so that the noise and the torque ripple of the motor in operation are reduced. The method comprises the steps as follows: obtaining a three phase stator current signal, and the electrical angle and the electrical angular speed of the motor rotor through the technologies of sensor sampling and a photoelectric coded disc or position sensorless detection; carrying out Clarke transformation and Park transformation on the stator current signal to obtain the stator current in a synchronous revolution dq coordinate system; substituting the obtained stator current signal in the dq coordinate system into a control equation of a current predictive controller of the permanent magnet synchronous motor, carrying out deadbeat control according to the given value of the obtained stator current in the dq coordinate system in an outer ring controller to obtain a stator voltage vector in the dq coordinate system; carrying out Park inverse transformation on the obtained stator voltage vector in the dq coordinate system, to obtain a pulse-width modulation (PWM) control signal of an inverter by a space vector pulse width modulation (SVPWM) method, controlling the stator current through the inverter, and then implementing the current predictive control over the permanent magnet synchronous motor.

The invention discloses a permanent magnet synchronous motor driving system capable of switching a winding. According to the permanent magnet synchronous motor driving system, a winding switch conversion device with a simple structure is utilized to realize automatic reconstruction of the winding. Meanwhile, operation switching of the low-speed and high-speed windings is realized with combination of double-inverter coordination control and flux weakening control so that range of operation rotating speed of the driving system is substantially widened, and operation efficiency and fault tolerance performance of the system are enhanced. In the low-speed state, single-inverter double-winding operation is performed; in the intermediate-speed state, double-inverter double-winding operation is performed; and in the high-speed state, firstly permanent magnet synchronous motor terminal voltage is limited by utilizing the flux weakening control mode, then the winding is switched and single-inverter single-winding operation is performed. A double-inverter circuit is adopted so that working modes of the system are flexible and various, i.e. both single-inverter operation and double-inverter operation can be realized, and thus the system has certain fault tolerance capability.

The invention provides a method for injecting a harmonic voltage to restrain a harmonic current of a PMSM (permanent magnet synchronous motor), which is characterized in that a ring to restrain the harmonic current is added to realize the closed-loop control for the harmonic current on the basis of extracting harmonic current components in the PMSM in real time, thus calculating to obtain harmonic voltage components which are required to be injected to restrain 5-order and 7-order harmonic currents of the PMSM; and then the obtained harmonic voltage components are injected into a three-phase control voltage in a speed control system of the PMSM so as to offset the 5-order and 7-order harmonic components in a motor current when the PMSM runs, thereby reaching the purpose of restraining the 5-order and 7-order harmonic currents. The method is used to solve the technical difficulty that current ZCP (zero crossing point) is required to detect accurately in a traditional mode to restrain the harmonic current, remarkably improves the current waveform of the motor, effectively restrains the 5-order and 7-order harmonic currents caused by the nonlinear characteristics of an inverter and the air-gap field distortion of the motor, effectively reduces the additional loss caused by the 5-order and 7-order harmonic current components, reduces the electromagnetic torque and the revolving speed pulse of the PMSM and improves the running efficiency and the running reliability of the PMSM.

A hybrid linear actuator features a central load shaft on which a plurality of solid-state magnetostrictive thrusters are positioned in operative relation to electric motors of a permanent magnet synchronous type to impart linear thrust force to the load shaft through clutch units also positioned thereon and under control of force and stroke amplification of output force from motor shafts projecting from the motors.

The invention discloses an automatic regulating apparatus for controller parameters of a servo driver of a motor and a method thereof. The apparatus comprises an inertia identifier, a parameter initial regulator, a parameter checker, a parameter optimizer, a parameter saving and displaying device, a speed controller, a position controller, a torque controller, a PWM (Pulse-Width Modulation) generator and a coded disc. In the invention, the servo driver of an alternating current permanent magnet motor automatically configures the parameters of the position controller and the speed controller according to different rotary inertias of mechanic load, checks and further optimizes the automatically configured parameters through the parameter checker and the parameter optimizer so that the position response and the speed response of the servo driver are relatively optimal. The servo driver of the alternating current permanent magnet synchronous motor automatically regulates the control parameters according to work occasions and achieves ideal control effect. The whole process is manual participation free and completed fully by the servo motor of the alternating current permanent magnet synchronous motor.

The invention discloses a method for controlling a PMSM (permanent magnet synchronous motor) servo system based on friction and disturbance compensation. In the method, a feedforward compensation method based on a friction model is combined with an auto disturbance rejection technology and the feedforward compensation method is complementary with the auto disturbance rejection technology mutually. In the method, a Stribeck friction model is utilized to carry out modeling on system frictions, a GA (genetic algorithm) is adopted to carry out offline identification on parameters, and an estimated value generated by an identification model carries out feedforward compensation; a state observer in the auto disturbance rejection technology observes and compensates overcompensation or undercompensation of the frictions as well as nondeterminacy and external disturbance caused by modeling errors in the system; and finally a differential tracker and a nonlinear control law are used to arrange a transient process for fixed position signals, thus solving the conflict between rapidity and overstrike and ensuring stability of the system and finite time convergence. By using the combined control, the compensation capacity of the system for the frictional nonlinearity can be improved effectively, the low-speed performance of the system is improved, and the tracking accuracy and the anti-disturbance capacity of the system are enhanced.

A permanent magnet synchronous machine with improved torque and power characteristics. A circumferential-oriented rotor assembly is provided with alternating permanent magnets and magnetic pole pieces. In order to reduce the amount of leakage flux in the rotor and increase the effective length of the permanent magnet, a trapezoidal or otherwise tapered permanent magnet structure is used. By alternating trapezoidal permanent magnet, and magnetic pole pieces, a higher intensity magnetic field is created in the air gap utilizing the same radial space in the motor without altering the weight or volume of the motor compared to conventional machines.

The invention relates to a temperature rise analytical method for predicting temperature of a permanent magnet in a permanent magnet synchronous motor (PMSM), belonging to the application electrical engineering design field; the method is characterized in that: distributed heat source of a motor is analyzed by a filed-circuit compact coupling method, comprising eddy current loss in the permanent magnet, iron loss in an iron core and copper loss in armature; on the consideration of precision requirements, the coupling analysis of a magnetic field and a temperature filed can be realized by single-way coupling mode. A thermal model of the permanent magnet synchronous motor is built based on a mixing method of a novel equivalent heat network and a finite element, heat parameters are rationally selected by adopting a combining mode of experimental measurement and empirical formula, the heat transferring coefficient and cooling condition of the motor are described completely, a stator and a rotor can be systematically combined by adopting air gap joints in the heat network, the stator and rotor unified temperature rise model is formed, the difficulty of measuring air gap temperature is avoided, material parameters are adopted at the practical working temperature, so as to lead the analysis to be rational; the accurate and optical method for predicting the temperature of the permanent magnet is realized by special correction processing in experimental links; in addition, the design method is used to give suggestions for model selection of the permanent magnet material in the motor.

A permanent magnet synchronous machine includes a stator, and a rotor which defines with the stator an air gap. The stator includes a plurality of teeth which are disposed in spaced-apart circumferential relationship and separated from one another by a tooth pitch. Each of the teeth has a shaft which terminates in a tooth head adjacent the air gap, with the tooth heads of neighboring teeth being separated from one another by a slot. The tooth heads are constructed to prevent saturation. The rotor has permanent magnets which are aligned in flux concentration direction and arranged to define a pole pitch, wherein a pitch ratio of tooth pitch to pole pitch is ≧2.5.

The invention provides a method for detecting the initial position of a magnetic pole of a rotor of a built-in permanent magnetic synchronous motor, belongs to the field of motor control, and solves the problems of over-complicated processing, easy occurrence of polarity misjudging, poor practicality and the like existing in the conventional method based on high-frequency signal injection for detecting the initial position of the rotor. The method comprises the following steps: constantly maintaining the stationary state of the rotor; injecting a rotating high-frequency voltage signal into a stator winding; detecting three-phase stator current and converting the three-phase stator current into two-phase static coordinates; acquiring an error signal capable of reflecting position information of the magnetic pole of the rotor through signal processing; adjusting the error signal by using a PI tracker so as to acquire an initial judging value of the position of the magnetic pole of the rotor; and injecting two impulse voltage vectors in opposite directions into the stator winding, comparing values of direct axis current components by detecting the three phase current and converting the rotating coordinates so as to determine the polarity of the magnetic pole, and finally acquiring the initial position angle of the magnetic pole of the rotor of the built-in permanent magnetic synchronous motor.

The invention discloses a sensorless control system of a permanent magnet synchronous motor. The sensorless control system comprises a flux linkage / current state observer and a counter electromotive force measurement module, wherein the flux linkage / current state observer is a sliding mode observer; the sliding mode observer is controlled by a sliding mode variable structure; and the coordinate system of the sliding mode observer is an estimated rotary coordinate system, is rotated at an angular speed and lags behind an electrical angle of the coordinate system. In a control parameter computation module, the error of a rotor position is calculated. The sensorless control system of the permanent magnet synchronous motor, can be used on a low-speed observation occasion and a height observation occasion at the same time and has strong practicability.

The utility model provides a back-to-back convertor of a wind power generation system. Two back-to-back convertors are connected in parallel. Each convertor comprises rectifiers on the side of a motor and an inverter on the side of a grid. The rectifiers on the side of the motor are conncted in parallel. An AC input end is connected with an outlet terminal on the side of a stator of a magneto alternator; direct-current output terminals of the two rectifiers on the side of the motor are connected with an independent voltage-stabilizing large capacitor, respectively. A positive terminal and a negative terminal of each of the capacitors are conneted with an inverter, respectively; output terminals of the inverters are connected to a grid after parallel connection. Each rectifier on the side of the motor is controlled by a digital processing chip DSP. When the two convertors run concurrently, circulatory zero-sequence current of the shunt circuit between the convertors is restricted to bezero; circuit loss is accordingly reduced, and circuit components are protected.

The invention relates to an automatic field-weakening method for a built-in permanent magnet synchronous motor, which solves the problem that field-weakening speed is difficult to widen due to the fixed rotor excitation and small reactance of armature reaction of a direct axis in the conventional permanent magnet synchronous motor in the market. In a rotor magnetic structure of the permanent magnet synchronous motor, a magnetic flux short-circuit block is arranged in a magnetic flux isolating layer in a quadrature axis direction with the help of an automatic adjustment action of a spring; when the rotary speed of the rotor is low, the short-circuit block is positioned at a low-speed position so that interelectrode magnet leakage through the isolating layer is small; when the rotary speed of the rotor is increased, the short-circuit block gradually deviates from the low-speed position to move towards the edge of the rotor under the action of rotating centrifugal force, which expands the interelectrode magnet leakage path; and the leakage magnet flux passing through the isolating layer is increased and the main magnet flux is reduced so that the aim of automatic filed-weakening widening speed is fulfilled in the motor body and a larger speed-adjusting range is reached. The method can be applied to the permanent magnet motors which have uncertain pole numbers and tangential or radial magnet structures.

The invention discloses a direct torque control system of a permanent magnet synchronous motor based on a terminal sliding mode, which belongs to the field of motor control. The system comprises a main circuit, a signal detection circuit, a rotational-speed outer-ring controller for the terminal sliding mode, a torque linkage inner-ring controller for an adaptive fuzzy sliding mode, a stator-linkage electromagnetic torque estimation module, an SVPWM module, a 3 / 2 coordinate transform module, and a rotor position / speed estimation module; the design on the rotational-speed outer-ring controller is realized by using a terminal sliding mode control method based on the adaptive estimation of load disturbance, and the rotational-speed outer-ring controller outputs direct-torque controlled demand signals; and the design on the torque linkage inner-ring controller is realized by using an adaptive fuzzy sliding mode control method, and the torque linkage inner-ring controller outputs two-phase alternating voltages in a two-phase stationary coordinate system; and through carrying out SVPWM transformation on the two-phase alternating voltages, a power switching element acted on an inverter of the main circuit implements the direct torque control of the permanent magnet synchronous motor. The direct torque control system in the invention has the advantages of quick torque response speed, good robustness, small tracking error, and capability of improving the reliability and static / dynamic characteristics of the system.

The invention discloses a direct torque control device and a direct torque control method for a permanent magnet synchronous motor. The DC bus voltage of an inverter and a current signal of the permanent magnet synchronous motor are output to a signal detection circuit; the signal detection circuit outputs the DC bus voltage and the current signal to a processor; meanwhile, a rotating speed pulse signal of the permanent magnet synchronous motor is output to the processor and is processed by the processor to form a proper switch signal which is then output to the inverter so as to control the motor. A proper voltage vector is selected from twelve synthesized voltage vectors according to a flux linkage error and a torque error and the position of the flux linkage in twelve sectors, and the duty ratio of the selected voltage vector is determined in real time according to the torque error so as to generate a proper inverter switch signal for controlling the permanent magnet synchronous motor. The number of the selectable voltage vectors in the traditional direct torque control is increased, the duty ratio of an acting vector is adjusted in real time according to the torque error, and the torque pulsation in the traditional direct torque control can be effectively reduced.

The invention provides a motor control device, a motor control system, a motor control module and a refrigerating unit, capable of reducing switching shock when switching from synchrony operation mode to non-position sensor mode. In a control device 6a comprising a dc vector control device for controlling rotating speed of permanent magnet synchronous motor consistent with speed instruction value omega i through an inverter, comprising a synchrony operation mode for driving the permanent magnet synchronous motor together with a rotating angle theta m' obtained by integraling the speed instruction value; and a non-position sensor mode for proceeding feedback control to rotating angle theta m of the permanent synchronous motor, comprising a switcher 19 that speculating shaft error (delta theta c) of the stator shaft of the permanent magnet synchronous motor and control system shaft of the dq vector control part, and when the speculated shaft error almost consistent with phase difference of current instruction value, the synchronous rotating mode is switched into the non-position sensor mode.

The present invention comprises a stator, and a rotor which is disposed oppositely to the stator with a gap interposed. The stator comprises a stator core, and a distributed stator winding mounted to the stator core. The stator core comprises a ring-like yoke core, and a plurality of teeth cores which protrude from the yoke core in the radial direction. The rotor comprises a rotor core, and a plurality of permanent magnets embedded in the rotor core. A pair of non-magnetic portions is created inside the rotor core and on both sides of the circumferential width of a permanent magnet for one magnetic pole. In the rotor core located on the stator side of the pair of non-magnetic portions, a pair of magnetic paths is created as the result of the creation of the pair of non-magnetic portions. Furthermore, a groove or hole is created on the outer circumferential portion of the rotor core and between the adjacent magnetic poles.

The invention provides a field weakening control method for a built-in permanent magnet synchronous motor. The method comprises the following steps: motor speed closed-loop control in a field non-weakening region: the output of a speed loop is the current directive value i<*>q of an axis q, the current directive value i<*>d of an axis d is calculated from i<*>q according to an MTPA relation, and i<*>d, i<*>q and the actual feedback values id and iq thereof are subjected to closed-loop control to output the voltage directive values of the axis d and the axis q; difference value amplitude-limiting processing: whether to enter a field weakening region is judged, if yes, an output voltage amplitude value controls a PI (Proportional-Integral) controller to work and controls a PI adjustor to perform difference value amplitude-limiting processing and output Deltaiq, otherwise, the output voltage amplitude value controls the PI controller not to work, and the output is 0; in case of entering the field weakening region, the output i<*>q of the speed loop is only used as the current directive value of the axis d after MTPA calculation, and the sum of the output of the front beat of the speed loop before entering the field weakening region and Deltaiq serves as the current directive value of the axis q in the field weakening region.

The invention relates to a permanent magnet synchronous motor (PMSM) AC servo system, which is composed of a DSP control panel, a rotary transformer, a main power circuit and a conditioning and protecting circuit, a motor body consists of an armature winding and a permanent magnet core rotor, wherein the motor is excited by a permanent magnet, and the DSP is used for realizing an field-orientated control algorithm, communication, sampling calculation of current and configuration output of a drive; the output of the rotary transformer enables data to be transmitted to the DSP via four-path DA transform chips and SPI of the DSP or multi-channel buffering; the DSP outputs pulse width modulation, is connected with voltage signals output by a current regulator, and is connected with a PWM1-PWM3 drive inverter which can convert the voltage signals into three-phase switch signals by CLARK inverse transformation, and the inverter outputs to the armature winding so as to control the armature winding of the motor to generate a rotary round magnetic field; and the main power circuit is composed of a direct current detection circuit with controllable rectification, an inverter, a current detection circuit, an overvoltage discharging circuit, a protection circuit and a driving circuit. The invention adopts the field-orientated control algorithm which can control the torque, speed and position state of the motor in real time and has good control performance.

The invention discloses a method and a device for controlling weak magnetism of a permanent magnet synchronous motor. The method comprises the steps: reducing the counter potential of the permanent magnet synchronous motor through regulating the set value of d-axis current and the set value of q-axis current under an equivalent rotor coordinate system, wherein the set value of the d-axis current and the set value of the q-axis current are obtained through the following methods: comparing an actual angular speed signal of a rotor with a preset angular speed signal, and performing proportional integral (PI) regulation on a comparison signal to obtain the set toque of the rotor; obtaining the initial set value of the d-axis current according to the set torque; obtaining the regulated value of the d-axis current according to the actual angular speed signal, an output voltage signal and the maximum set voltage value of a traction inverter; obtaining the set value of the d-axis current according to the initial set value of the d-axis current and the regulated value of the d-axis current; and then, obtaining the set value of the q-axis current according to the set torque and the set value of the d-axis current.

The invention relates to the technical field of PMSMs, solves a coupling problem during online identification of multiple parameters of a surface-mounted type PMSM, and achieves online decoupling identification of PMSM inductance, stator resistance and rotor flux linkage. Accordingly, the technical scheme adopted by the invention is that an online decoupling identification method of multiple parameters of the PMSM comprises the steps as follows: 1) identifying and coupling analysis of parameters of the PMSM; 2) a decoupling identification strategy, wherein voltage deviation before and after D shaft current injection is used for increasing the order of a motor mathematical equation, so that the decoupling identification of multiple parameters of the surface-mounted type PMSM inductance, the stator resistance and the rotor flux linkage are achieved; 3) neural network identifier design, wherein according to a parameter online identification problem of the PMSM, online identification is performed on motor parameters by adopting a self-adaptive neural network structure and a weight convergence algorithm based on a least mean square algorithm. The method is mainly applied to the design and manufacture of the PMSM.

A permanent magnet generator is described. The generator includes a shaft which defines a longitudinal axis. A rotatable magnetic field assembly is mounted on the shaft and adapted for rotation about the shaft. The magnetic field assembly includes a plurality of axially magnetized magnets which are retained in a cavity about the shaft for generating an axial magnetic flux. A plurality of vanes are mounted on the magnetic field assembly housing for rotating the magnetic field assembly about the shaft when a fluid flows past the vanes. A stationary armature assembly is also located around the shaft in a position axially spaced from the magnetic field assembly. The armature assembly generates AC power when the magnetic field assembly is rotated. The stationary armature assembly includes an armature housing. An axial bore is formed through the armature housing for receiving the shaft. The armature housing defines a cavity about the axial bore in which a plurality of laminated bars are retained. A plurality of electrically conductive wires are wrapped around the laminated bars to form coils.

The invention discloses a method for self-adjusting control parameters of a speed ring of a permanent magnet synchronous motor based on fractional orders. An integer-order proportional integral (PI) controller in an alternating current servo system of the permanent magnet synchronous motor is replaced by a fractional-order PI controller, parameters of the fractional-order PI controller are automatically adjusted, and the alternating current servo system of the permanent magnet synchronous motor can be controlled. The method specifically comprises the following steps of: firstly, acquiring current and speed signals of the alternating current servo system; secondly, identifying a speed ring controlled object model of a permanent magnet synchronous motor servo system according to the acquired signals, and identifying the parameters of the model; and finally, optimally adjusting the control parameters, and thus obtaining optimal control parameters. According to the method, the original integer-order PI controller is replaced by the fractional-order PI controller, and the parameters of the controller are automatically adjusted; the parameters of the controller are optimized by using a pattern search algorithm; and the adjusted parameters of the controller are high in robust, high in anti-disturbance capacity and high in control accuracy.

The invention relates to a method for determining an initial position angle of a rotor of a permanent magnet synchronous motor, which belongs to the field of motor control. The invention aims to solve the problems that a rotor detection method provided by a patent of a method and a device for detecting an initial position of a motor rotor in an alternating current servo system has complex logical decision and easy failure of detection. The method for determining the initial position angle of the rotor of the permanent magnet synchronous motor comprises the following steps: controlling the amplitude and the phase of the current of a d shaft and a q shaft under a two-phase synchronous rotating shaft system to further control the amplitude and the phase of the current of a three-phase stator under a three-phase stationary shaft system; controlling the rotation of the motor rotor under a given stator magnetic field; and according to a pulse signal fed back by an incremental encoder, making the direction of the given magnetic field gradually and circularly approach the actual position angle of the rotor until the direction of the given stator magnetic field corresponding to the current of the d shaft and the q shaft is coincident with the direction of a rotor magnetic field. The direction of a given stator current magnetic field is changed by 90 degrees, so that a torque vertical to the direction of the rotor magnetic field is generated on the rotor, and according to the rotating direction of the rotor, the initial position angle of the actual rotor is determined.

The invention discloses a generator system for wind power generation and a variable speed control method; the system comprises a permanent magnetic synchronous generator of which the electrical energyoutput is connected with a Vienna rectifier device, and is characterized in that a stator winding of the permanent magnetic synchronous generator comprises two sets of triphase windings with electrical degree difference of 180 degrees and unconnected neutral points thereof; the Vienna rectifier device comprises two Vienna rectifiers with identical structure, which are in parallel connection withthe DC side with a central point O connected with a DC bus capacitance midpoint; the AC side is connected with the two triphase windings of the generator respectively; a Boost inductance of the Viennarectifier is directly provided by the leakage inductance of the windings of the generator; each Vienna rectifier device is controlled by a DSP controller to maintain the balance of the DC bus voltageby the phase current and line voltage collected in the AC side and the bus voltage collected in the DC side; and the variable speed control of the generator is realized by collecting the rotating speed of a fan and the current wind speed.

A low-cost sine-wave drive for a 3-phase permanent magnet synchronous AC machines (PMSM) in open-loop control is based on the measurements of two linear Hall sensors. The two Hall sensors are excited by a magnetic ring with the same pole number as the PMSM rotor magnet and sinusoidal flux distributions. The output signals of the Hall sensors are unified through a two-phase-type phase-lock-loop in order to reduce the impact of the sensor mounting non-uniformity during mass production. The peak torque and speed of motor is simply controlled by adjusting the amplitude of pulse-width-modulation carrier. Smooth torque control is achieved due to sinusoidal 3-phase currents. Such a simple sine-wave drive can be achieved with or without the assistance of a micro-controller unit (MCU). No current sensor is required for the motor phase current detection. This motor can be used in industrial applications where there is no strict requirement on torque response and constant speed control of PMSM machines.