2422 results about "Voltage vector" patented technology

A controller for an AC electric motor, includes a Feed Forward Torque Controller and a load model. The Torque controller directly derives a torque related component of applied motor voltages from a signal representing a torque command input T* and at least one motor parameter. The load model derives a motor speed value including a model of motor speed behaviour of the AC electric motor to provide an output signal which represents the motor speed of the AC electric motor. This motor speed output signal is used in determining a frequency of rotation of an applied motor voltage vector. Where an input to the load model is the signal representing the torque command input T*, the load model uses the signal representing the torque command T*, at least over a part of an operating speed range of the AC motor which includes zero speed, to determine the motor speed output signal.

A device to regulate current produced by a permanent magnet machine responsive to a plurality of phase current signals. The motor produces torque for application on a shaft. A processing and drive circuit responsive to a direct current command signal and a quadrature current command signal produces phase current signals for input to the motor. A command circuit responsive to the phase current signals, an angular position of said shaft, and a voltage input command signal to produce a direct current error signal and a quadrature current error signal. A control circuit responsive to the direct and quadrature current error signals produces the direct voltage signal command and the quadrature voltage signal command. The control circuit has a direct and quadrature proportional gain, integrator and clamp circuits. An algorithm produces limited or clamped voltage modulation index signals to obtain maximum efficiency and maximum torque per ampere in the speed range. The algorithm ensures that the current regulator does not run out of voltage by limiting the voltage vector to the achievable voltage vector range that provides maximum torque per ampere and maximum efficiency.

The invention discloses a modulating method for the optimized PWM of restrainable harmonic waves, which utilizes the combination of space voltage vectors (SVPWM) to realize the elimination of 'm' ('m' equals to 6 multiplied 'j' and plus or minus1; 'j' equals to 1, 2, ellipsis) times of harmonic wave, wherein, 'm' refers to a certain odd number which is not divisible by 3 and comprises 5, 7, 11, 13, etc. The method of the invention is characterized in that the method can be realized by programming, thereby not only solving the problem of calculated amount or look-up table memory capacity existing in a SHEPWM method, using the combined voltage vector to approach the circular trace of a flux linkage, and helping to reduce torque pulsation, but also fulfilling the task of selectively eliminating the harmonic wave.

A distributed power generating system enables very rapid and reliable start-up of an engine used to generate back-up power, thereby substantially reducing the need for stored power. More particularly, the distributed power generating system comprises a power bus electrically coupled to commercial power and to a load, an engine comprising a rotatable shaft, a starter/generator operatively coupled to the shaft of the engine and electrically coupled to the power bus, and a temporary storage device electrically coupled to the power bus. The distributed power generating system further comprises a control system adapted to detect a failure of the commercial power and cause the starter/generator to start the engine from a standstill condition. The control system provides the starter/generator with an initial voltage vector selected to rapidly bring the engine to an operational speed sustainable by the engine alone. The temporary storage device supplies electrical power to the power bus for delivery to the load and for powering the starter/generator until the engine reaches the operational speed, whereupon the control system causes the starter/generator to take over supply of electrical power to the power bus for delivery to the load. The control system starts the engine upon detection of a voltage on the power bus below a predetermined lower limit. After the engine has started, the control system monitors speed of the engine to determine whether the operational speed is reached. The control system terminates operation of the engine upon detection of a voltage on the power bus above a predetermined upper limit.

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 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 discloses a dead-beat based direct torque control method for a permanent magnet synchronous motor. Errors between given magnetic linkage amplitude and actual magnetic linkage amplitude as well as between given torque amplitude and actual torque amplitude are compensated accurately and simultaneously within a control cycle, and dead-beat control of magnetic linkage and torque is realized. Meanwhile, a space voltage vector modulation method is introduced into a control system to enable switching frequency to be constant. By the control method, system performance can be well improved, magnetic linkage and torque pulsation can be lowered obviously, dynamic response speed of the torque is equivalent to that of a conventional direct torque control scheme, and the direct torque control method basically keeps the advantages of simple structure and fast dynamic torque response.

The invention relates to a method for simulating an aero-optical effect. The method comprises the steps of conducting thermal and structural analysis to an optical window by adopting a finite element analysis method to obtain a finite element analysis result, and calculating multi-frame wave-front errors according to the finite element analysis result; fitting the current frame wave-front error to be a Zernike polynomial coefficient vector q; calculating control voltage vectors of all actuators of a deformable mirror and control voltage vectors of all actuators of a tilting mirror according to the q; and adjusting the actuators of the deformable mirror according to the control voltage of the deformable mirror, adjusting the actuators of the tiling mirror according to the control voltage of the tiling mirror, acquiring and saving distorted images on an imaging detector and again fitting the q according to the current frame wave-front error. The invention additionally discloses a system for simulating the aero-optical effect. By using the method and the system provided by the embodiment of the invention, dynamic distorted image data under the influence of the aero-optical effect can be obtained and experimental conditions are provided for researches on the correction of the aero-optical effect.

The invention discloses a control method of an alternating voltage sensorless high voltage direct current transmission converter, belonging to the technical field of electrical equipment and comprising the following steps: establishing a stator resistor and an inductor for a virtual motor; building relative position relationships among a current vector, a voltage vector and a flux linkage vector, and analyzing a vectorgram; establishing a converter and flux linkage mathematic model, and calculating a virtual flux linkage vector of a system to obtain a power feedback quantity of the system; acquiring an active control signal and a reactive control signal of the system through a direct power control algorithm, and generating a PWM trigger converter for respectively and independently controlling the active power and reactive power of the system; and utilizing MATLAB simulation software to set up a system model for verifying, and obtaining a systematic selection device when the verification is successful. By utilizing Matlab/Simulink to set up a corresponding simulation model, the designed method is verified to have rapid response speed, the voltage and power after startup can still reach stable values after about 2 power frequency periods and have high steady state precision.

The motor control device includes a current detecting portion for detecting a phase current that flows in an armature winding of a stator of a three-phase motor based on current that flows between an inverter for driving the motor and a DC power supply. The motor control device performs a position sensorless vector control for the motor based on a control current that is obtained by a three-phase to two-phase conversion of the phase current based on an estimated rotor position of the motor. The motor control device farther includes a superposing portion for superposing a superposed voltage having a predetermined frequency on a drive voltage for driving the motor and an estimating portion for deriving the estimated rotor position based on the superposed current that is extracted from the control current and flows in the motor in accordance with the superposed voltage. A voltage vector locus of the superposed voltage from the superposing portion presents an ellipse.

Methods, system and apparatus are provided for overmodulation of a five-phase machine in a vector controlled motor drive system that includes a five-phase PWM controlled inverter module that drives the five-phase machine. Techniques for overmodulating a reference voltage vector are provided to optimize voltage command signals that control a five-phase inverter module to increase output voltages generated by the five-phase inverter module.

The invention discloses a grid-connection control method for solar photovoltaic power generation and belongs to the field of solar photovoltaic power generation. The method is characterized in that: constant voltage control of a direct-current bus is taken as a basic starting point and the output voltage and current of a photovoltaic cell are adjusted by adjusting the pulse-width modulation (PWM) duty ratio of a DC/DC converter so as to realize the tracking control of the maximum output power point of the photovoltaic cell; and in addition, stable and grid-connection running of a photovoltaic generating system is realized and the constant voltage of the direct-current bus is maintained by adjusting the output current of a DC/AC grid-connected inverter. The tracking control of the maximum power point of the photovoltaic cell is characterized in that: the variation track of a power-voltage vector is obtained by sampling the output voltage and current of the photovoltaic cell at three or more points and is matched with a preset variation mode so as to determine the adjusting direction of the output current. During grid-connection running, the PWM duty ratio of the inverter is adjusted by using the measured voltage amplitude, phase position and frequency information of a power grid so as to synchronize the voltage generated by the system and the power grid. Moreover, the voltage of the direct-current bus is kept constant by using high-speed feedback of the output current of the inverter, so that the power of the system fed in the power grid is close to the power generated by a solar cell to the maximum.

The invention discloses a control method of a drive system, the drive system, and a new energy vehicle. The method obtains a current temperature value of a power battery in real time; when the temperature value is lower than a first preset temperature threshold, the temperature is raised to restore the drive capability of the drive system. A motor controller applies a periodic alternating voltagevector to a motor, the voltage vector is utilized to modulate bus current of a power battery to alternate, and during the process, the battery is driven to be repeatedly charged and discharged periodically to increase the temperature of the battery. Until the temperature value reaches a second preset temperature threshold, the battery is warmed to a desired operating temperature and the motor controller stops applying the voltage vector. Three-phase winding of the motor and three sets of bridge arms are used during the heating of the power battery. The recovery of the drive capability of the drive system is more economical without the need for additional external heating equipment. During the entire process of applying the voltage vector, the power battery is continuously and uniformly heated, the battery heating efficiency is very high, and rapid recovery of the drive capability is achieved.

The invention provides a method and device for measuring position compensation angles of a permanent magnet synchronous motor rotor, wherein the method comprises the following steps: setting a forcible magnetic field directional angle Theta Force; setting component instruction value of a d shaft voltage as u*d=0; inputting the component instruction value u*q of a q shaft voltage which can enable the permanent magnet synchronous motor to enter into a zero speed shaft locking state; according to the forcible magnetic field directional angle Theta Force, obtaining voltage vectors by virtue of PARK inverse transformation of u*d and u*q; generating a power device pulse-width signal needed by a voltage source inverter by a space vector pulse width modulation (SVPWM) algorithm; driving the permanent magnet synchronous motor to rote to a position of ThetaForcee+90 DEG by the voltage source inverter; obtaining the angle Theta xr read by an absolute encoder mounted on the rotor; and calculating the compensation angle that Theta c= Theta Force+ 90 DEG-Theta xr. The method provided by the invention can be simply, conveniently and easily realized; a current sensor is unnecessary to work, and the flitter is not existed during initial location.

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 distribution line single-phase break line judgment and positioning method based on a line voltage vector criterion. The distribution line single-phase break line judgment and positioning method comprises the following steps: step A, acquiring and counting three-phase line voltage; step B, verifying the three-phase line voltage vector; step C, judging a break line fault; step D, outputting the judgment result; step E, positioning the break line fault section. The distribution line single-phase break line judgment and positioning method disclosed by the invention has the following benefits: 1. the voltage vector is used as the parameter for judging the break line fault and is a little influenced by the three-phase load change situation, so that the break line fault can be normally recognized under the situations of no-load, light load, heavy load and three-phase load imbalance of the line; 2. the three-phase mains voltage fluctuation is low in influence; 3. the range of surveillance is wide, and a break line monitoring device can accurately judge and recognize the single-phase break line of the line from the mounting position to a line power supply; 4. the break line monitoring device is convenient to mount and implement and is mounted by a parallel connection method, and the existing three-phase voltage transformer on the line can be directly used as a voltage measurement input device.

The invention discloses a control method of an open winding permanent magnet synchronous motor system of a hybrid inverter. The control method comprises the following steps: after acquiring voltage and current of a three-phase stator of a motor, performing three-phase/two-phase static coordinate transformation to obtain voltage and current under a two-phase static coordinate system, thereby obtaining actual feedback values of electromagnetic torque and stator flux linkage; obtaining an initial given value of the electromagnetic torque through a PI (Proportional Integral) controller so as to obtain given values of the electromagnetic torque and the stator flux linkage; then combining output of a capacitor voltage PI controller to obtain final given voltage vectors of two inverters; finally generating a switching signal of the inverters through space vector pulse width modulation; and triggering a switching device of the hybrid inverter to realize direct torque control of the open winding permanent magnet synchronous motor. According to the control method, wide-range operation of low, medium and high speed of the open winding permanent magnet synchronous motor is realized, the electromagnetic torque in a motor acceleration process is increased, the voltage utilization rate of a direct current voltage source is improved, and high-speed constant-power operation of the permanent magnet synchronous motor is guaranteed.

Apparatus and methods for phase current detection used for driving a motor by supplying outputs from a pulse width modulation (PWM) converter to the motor. One method presented provides detecting a DC link current and a vector pattern, determining whether a voltage vector lengths exceeds a predetermined value, and adjusting the voltage vector by adding a positive or reversed voltage based upon the above determination and an integrated error value.

The invention is concerned with a controller of side converter to excitation electrical source web of double fed variable speed constant frequency wind generator. It controls current by a deadbeat control based on predicted current control, turns the current command signal of dq coordinate to two-phase immobile coordinate to get positive and negative order current present value of alpha and beta axes. Get present value of current to two-phase immobile coordinate through addition operation and carry immobile coordinate commutation about current of power system to get alpha and beta component of actual current value. Make the difference of command and present value, and get inductance pressure drop according to change ratio of current to count the input voltage, and get impulse signal to control on-off tube through SVPWM (space voltage vector). It keeps the control precision of DC voltage, eliminates influence to rotor side converter of fluctuation to DC side voltage, restrains common-mode voltage and differential-mode voltage output by rotor side converter to reduce burden of processor under lopsided state of power system.