505 results about "Linear induction motor" patented technology

A control system for a linear motor adapted to accurately supply a moving window of power to the stator coils. A plurality of individually switched stator coils run the length of a linear motor to move a rotor down the long axis of the stator. Accurate inductive-based position sensors continuously provide position data for the moving rotor. A processing unit calculates a proper time delay from a source voltage peak in order to apply power to the next stator coil in the moving direction of the rotor such that no DC offshoot / undershoot occurs. The linear motor control system optionally includes a failure prevention switching scheme in which pairs of individual stator coils on opposite sides of a double-sided stator are switched together.

Wave energy conversion to produce electricity uses wave-engaging articulated, forward and after barges connected to a center inertial barge. A damper plate attached to the central barge minimizes heaving to increase stability. The barges use composite materials, steel or other materials that can withstand the impact and wear caused by a corrosive weather environment. A movable ballast weight in each barge adjusts the mass moment of inertia, and changes the natural pitching frequency. Electrical energy is generated from the motions of the barges and the movement of the movable ballast weights being converted by linear induction motor / generators and / or Pelton Wheel hydraulic systems connected to electrical generators. A dynamic computer control system controls the energy generating system to keep the forward / after barges and the movable ballast moving in phase with the wave excitation force. During dangerous wave action, the system is submerged and then re-surfaced when the waves have subsided.

The invention discloses a motor parameter detection method and a motor parameter detection device. The motor parameter detection method comprises the following steps: opening the circuit of one of phase windings of a motor; detecting stator leakage inductance and rotor leakage inductance; applying rated voltage with higher frequency than rated power between the other two phases of the motor; and detecting the stator leakage inductance and the rotor leakage inductance according to the computational formula of the stator leakage inductance and the rotor leakage inductance. The invention provides the off-line motor parameter detection method and the motor parameter detection device under the static condition of the rotor of an induction motor, which achieve high accuracy of motor parameter detection through reducing the influences of voltage errors and a skin effect as long as current or voltage with different frequencies is applied between the two phases of the motor in sequence.

An HVAC system has at least one variable speed controller for an AC induction motor, especially of the Permanent Split Capacitor (PSC) type. The variable speed controller provides switched power via a modulating triac to the main coils of the motor and constant power via an on / off triac to the auxiliary coils during operation. A large value capacitor is placed in line with the auxiliary coils to reduce power consumption and current draw over that of known systems. Power to the motor can be turned off to provide for motor speed sensing through monitoring the frequency of a generated voltage when the power is turned off. Frequency-based motor speed sensing is accomplished by shutting off all current to the motor and measuring zero crossings on the generated voltage of the decaying magnetic field. The controller can be easily retrofitted onto existing motors. An optional controller bypass is provided to run the motor at rated speed in case of controller failure.

A control system for a linear vibration motor capable of eliminating necessity of a separate sensor of detecting the motion of the motor. The linear vibration motor includes a stator provided with a winding, and a vibrator provided with a permanent magnet. The winding is fed with a drive current to generate a magnetic field which interacts with the permanent magnet to cause the vibrator to reciprocate linearly relative to the stator for producing a vibration. The control system includes a controller which detects an ongoing amplitude, i.e., the motion represented by the displacement, speed, or acceleration of the vibrator and provides ON-periods of feeding the driving current to the winding in a varying amount based upon the ongoing amplitude detected in order to keep a vibration amplitude of the vibrator constant. The controller is characterized to provide OFF-period in which the controller instructs not to feed the drive current and in which the controller detects a voltage developed across the winding and determines the ongoing amplitude based upon the detected voltage. Thus, the winding can be best utilized commonly to drive the motor and to sense the ongoing amplitude or motion of the vibrator, thereby eliminating an additional sensor for detection of the motion of the vibrator.

A motor driving apparatus for driving a linear vibration motor includes an order output determining unit for determining a motor output which is required of the linear vibration motor, and a driving frequency determining unit for determining a driving frequency of the linear vibration motor based on the determined motor output. An amplitude-fixed AC voltage having a frequency which is equal to the determined driving frequency is applied to the linear vibration motor, whereby the output of the linear vibration motor can be controlled without changing the amplitude value of the driving voltage which is applied to the linear vibration motor.

A linear vibration motor includes: a top cover; a bracket coupled with the top cover to provide an internal space; a vibration unit having a mass body mounted at the internal space and linearly moving in a horizontal direction; an actuator having a magnet fixed to the mass body and a coil installed within a range of a magnetic field of the magnet and generating electromagnetic force to allow the vibration unit to move linearly in a horizontal direction; and a buffer member disposed in a space between the mass body and the bracket and limiting displacement of the vibration unit.

A simple permanent-magnet-excited maglev geometry provides levitation forces and is stable against vertical displacements from equilibrium but is unstable against horizontal displacements. An Inductrack system is then used in conjunction with this system to effect stabilization against horizontal displacements and to provide centering forces to overcome centrifugal forces when the vehicle is traversing curved sections of a track or when any other transient horizontal force is present. In some proposed embodiments, the Inductrack track elements are also employed as the stator of a linear induction-motor drive and braking system.

The invention discloses an exciting current given device for an induction motor of an electric vehicle. On the basis of the prior art, the exciting current given device is additionally provided with an exciting current limiting calculation module and a limiting PI (proportional integral) control module. When the induction motor normally runs, the calculated amplitude limiting maximum value (isd.Max) of the exciting current decreases along with the increase of the real synchronous speed omega e. The exciting current isdref of a voltage loop PI controller decreases under the condition of invariable maximum voltage vector (usm). Due to the decrease of the exciting current (isdref), the counter electromotive force of the induction machine decreases, therefore, under the condition of invariable busbar voltage uDC, the induction motor can rise to a higher rotating speed. In addition, according to the exciting current given device of the induction motor of the electric vehicle, the calculation of switching points among a constant torque area, a constant power area and a constant voltage area is eliminated, so that the level jump of output exciting currents caused by the inaccurate calculation of switching points can be effectively prevented, the given value of the exiting currents can vary stably, the joggling of the induction motor control caused by the level jump of the given valueof the exciting currents is reduced, and the safety of the induction motor control is improved.

The invention discloses a linear induction motor constant slip frequency vector control method. The method comprises the steps as follows: detecting the rotation speed of a rotor of a linear induction motor, calculating the magnetic chain space position angle Theta<s> of the rotor according to the given slip frequency electric angular velocity Wsl; calculating the excitation voltage Usm and torque voltage Ust according to the magnetic chain space position angle Theta<s> and the given slip frequency electric angular velocity Wsl and combining a given torque T and a rotor time constant Tr; generating modulation pulses by pulse-modulating the excitation voltage Usm and the torque voltage Ust and the DC voltage output by the power supply; converting the DC voltage output by the power supply into the AC electricity so as to be supplied to the linear induction motor according to the modulation pulse. The invention also discloses a linear induction motor constant slip frequency vector control system. The linear induction motor constant slip frequency vector control method and system of the invention can realize the constant slip frequency vector control of the linear induction motor.

The present invention provides a system and apparatus that includes an induction motor and / or a fan assembly. The motor includes a housing having an aperture and a shaft axially disposed within the housing and having an end extending though the aperture. The motor also includes a rotor that has one or more sets of radius extenders connected to the shaft within the housing, and a stator disposed within the housing and separated from the rotor by an air gap. The rotor typically includes one or more sets of permanent magnets attached along a perimeter of the radius extenders and at least a portion of the radius extenders is made of a magnetically conductive material. The stator typically includes a core structure of magnetically conductive material having a set of slots arranged on an internal face of the core structure and one or more sets of coils disposed within the slots.

A system including an induction machine with a toroidally wound stator and a squirrel cage rotor is presented. The toroidally wound stator has a plurality of phase windings. A position sensor may be operatively connected to the induction machine for providing a position indication that is indicative of a relative position of the rotor and the stator. The system also includes an inverter having a plurality of solid-state switches and a control system. The inverter has the same number of phases as the toroidal induction machine. The inverter is connected to selectively energize the phase windings. A programmable microprocessor, such as a digital signal processor, is operatively connected to the induction machine and includes a program to implement vector control of the induction machine. The microprocessor can also control the inverter so that the induction machine operates with a predetermined number of poles using pole phase modulation.

A control apparatus for an induction motor is provided and includes a rotating-speed locked loop and a feed-forward magnetizing-axis angular position emulator. The rotating-speed locked loop emulates a speed control loop of the induction motor for producing an emulated torque current and an emulated rotor angular speed. The feed-forward magnetizing-axis angular position emulator receives the emulated torque current and the emulated rotor angular speed for producing a feed-forward estimated magnetizing-axis angular position, wherein according to the feed-forward estimated magnetizing-axis angular position, a first voltage controlling the induction motor is transformed from a synchronous reference coordinate system of the induction motor to a static reference coordinate system of the induction motor, and a two-phase current detected from the induction motor is transformed from the static reference coordinate system to the synchronous reference coordinate system. The state the stator angular frequency is at zero can be skipped through the apparatus.

This invention discloses one line sensor motor control method, which gets line sensor motor initial magnetic linkage real value and linkage rate according to the input voltage of line sensor motor, wherein, it gets line sensor motor stator magnetic linkage range reference value and frequency value through collecting line sensor motor real speed; then it combines initial linkage aim shape to determine property motor initial voltage space vector and linkage frequency for the reference values.

The vector control device includes: secondary magnetic flux command computing means (40) for computing a secondary magnetic flux command to an induction motor (6) by taking a maximum voltage that an inverter (4) can generate into account on a basis of a torque command from an external, a DC voltage to be inputted into the inverter, and an inverter angular frequency, which is an angular frequency of an AC voltage to be outputted from the inverter; q-axis / d-axis current command generating means (8 and 9) for generating a q-axis current command and a d-axis current command on a d-q axes rotating coordinate system in reference to a secondary magnetic flux of the induction motor (6) on a basis of the torque command and the secondary magnetic flux command; output voltage computing means (voltage non-interference computation portion 14, adder 17, and adder 18) for computing an output voltage that the inverter (4) is to output on a basis of the q-axis current command, the d-axis current command, and a circuit constant of the induction motor (6); and voltage command / PWM signal generating means (50) for controlling the inverter (4) for the inverter (4) to output the output voltage.

The invention discloses an induction motor bearing fault diagnosis system and diagnosis method based on wavelet-spectral kurtosis. The induction motor bearing fault diagnosis system based on the wavelet-spectral kurtosis comprises a wavelet-spectral kurtosis analysis module, a time domain parameter statistical analysis module, an FFT analysis module, a Hilbert envelope demodulation analysis module, a spectral kurtosis analysis module, and the like; the wavelet-spectral kurtosis analysis module includes two data preprocessing methods of wavelet and wavelet packet, which can realize the identification and feature extraction of multiple faults in a motor bearing coupled fault vibration signal; the time domain parameter statistical analysis module monitors whether the motor bearing is abnormalor not by calculating kurtosis values of time domain sensitive parameters; and a spectrum analysis module and the Hilbert envelope demodulation analysis module mainly determine the feature extractionof the single bearing fault of the motor. The induction motor bearing fault diagnosis system based on the wavelet-spectral kurtosis realizes the integrated design of the induction motor bearing faultdiagnosis method, and can quickly and effectively process and analyze the single and composite fault signals of the motor bearing and obtain accurate diagnosis results.

The invention relates to a method for identifying on-line parameters of a linear induction motor, which realizes the closed-loop control of exciting current component and thrust current component of a motor and enables the exciting current component to be equal to the thrust current component under the directional control of an indirect magnetic field. The method comprises the following steps: adjusting a secondary time constant value used in a motor controller and changing the specified slip frequency and the synchronous frequency of the motor in the controller by an on-line identification arithmetic to adjust the synchronous angle for the magnetic field to locate; searching the minimum value of the input current of the motor in a steady-state operation condition when the load torque is kept constant, enabling the secondary time constant used in the motor controller to be approximate to the real value of the secondary time constant of the motor, therefore realizing the on-line identification of the secondary time constant of the motor. The invention can realize the correct directional control of the indirect magnetic field of the linear induction motor without depending on other motor parameters hard to be controlled exactly through on-line operation, avoid influence of end effect, parameter change and the like on the control performance, does not need the input voltage component of the motor and improves the practicability of a parameter on-line identification system.

A linear vibration motor includes a stator formed of an electromagnet with a winding, a vibrator provided with a permanent magnet and a control unit for controlling a driving current supplied to the winding of the electromagnet. The linear vibration motor is configured to reciprocate the vibrator relative to the stator. A method for controlling operation of the linear vibration motor includes: providing a non-energization period during which no driving current flows through the winding of the electromagnet, the non-energization period being equal to greater than a ¼ cycle; detecting an electromotive voltage induced in the winding as the vibrator makes vibrating movement within the non-energization period; detecting the displacement, velocity or acceleration of the vibrator based on the electromotive voltage thus detected; and controlling the driving current supplied to the winding based on the displacement, velocity or acceleration of the vibrator thus detected.

A vector-controlled, dual inverter system for a three-phase induction motor is disclosed. The inverter system comprises a first inverter system which is connected to one end of three phase windings of a stator and performs compensation of a back electromotive force; and a second inverter system which is connected to the other end of the three windings of the stator and performs reactive power compensation.

A linear motor accelerated impact spring fatigue test device involves high frequency, high speed, and high load impact of vibration spring fatigue life test device. The invention includes cylindrical linear induction motor, electric control parts and fuselage. Since the invention mainly has simple structure, high efficiency, and can simulate the actual work environment to inflict spring sample high-speed, high-frequency, high-thrust and wide-vibration impact vibration, high precision detection, simple operation, and other features, so the invention can be widely applied in detection in the course of high-speed, high-frequency, high-thrust, wide trip vibration of the impact of the fatigue life of spring, especially the multi-helical spring fatigue. It provides the development of high-frequency reciprocating movement springs with a more accurate basis, and improves their quality, which could improve the performance of such equipment and competitiveness.

A motor drive control apparatus for driving and controlling a linear vibration motor having a mover supported by a spring, with an AC current. The motor drive control apparatus includes a waveform creation unit for creating a comparative current waveform to be a reference of a driving current for the linear vibration motor based on the operating condition of the linear vibration motor, a current detector for detecting the driving current, and a controller for controlling a driving voltage of the linear vibration motor so that a difference between the comparative current waveform and a waveform of the current detected by the current detector becomes zero. The frequency of the driving current is controlled to be close to the resonance frequency of the linear vibration motor, based on the comparative current waveform. Accordingly, the driving frequency of the linear vibration motor can always be brought to the resonance frequency without using a sensor for detecting a displacement, speed, or acceleration of the mover, for example.

The invention discloses a full speed domain torque maximizing vector control current distribution method for an induction motor. In the method, voltage limitation, current limitation and physical characteristic limitation of the motor are comprehensively considered, and a given torque maximizing exciting current vector value and a given maximum torque current vector value are obtained by deriving in different speed domains. Due to the adoption of the method, the current utilization ratio and efficiency of an induction motor driving system can be greatly increased, and the full speed domain torque output capability of is enhanced.

An electric power steering (EPS) device including a rack actuator that applies assist force to a rack shaft, a column actuator that applies assist force to a column shaft, and an ECU that controls operation of the actuators by supplying drive power to motors, each of which is a drive source of the corresponding one of the actuators. A permanent magnet motor (BLDC) is employed as the motor of the rack actuator and an induction motor, which is a non-permanent magnet motor, is used as the motor of the column actuator.

A linear induction generator for use in a weapon system comprising a matrix of coils, a matrix of magnets, a spindle assembly, a matrix of coils, and a dust cover there over. This generator is mounted onto a weapon receiver of the weapon system to generate raw electric current. The raw current is then rectified and delivered to either a battery or directly to the electronic devices.

A totally enclosed fan cooled (TEFC) induction motor or other type of induction motor auxiliary cooling system has a buffet thermal shroud that is oriented in opposed spaced relationship over existing motor housing cooling fins. An airflow channel is defined between the motor cooling fins and the shroud, for direction and passage of a cooling airflow. Tabs are oriented in the airflow channel between opposed cooling fins where they are in thermal and fluid communication with the cooling air flow. In some embodiments the tabs are shroud fingers that project inwardly from the shroud. The tabs or shroud fingers create turbulence in the cooling air flow that increases convective heat transfer efficiency and contact time between the cooling air and motor cooling fins. Tabs or shroud fingers also absorb heat from the cooling air flow. Shroud fingers also transfer that absorbed heat conductively to the shroud.

The invention discloses an induction motor speed sensorless drive control method based on virtual voltage injection, firstly, a virtual voltage signal is injected into a motor magnetic chain and a rotation speed observer, thus, difference exists between input of the motor magnetic chain and the rotation speed observer and instruction input of the motor; secondly, any type of the motor magnetic chain and the rotation speed observer are taken as a basis, and consequently, a rotation angle of the motor magnetic chain and a rotation speed of a motor rotor are estimated, and the induction motor isdriven by certain control strategy (such as vector control) to run regularly; then, according to the the signal designed by the method and only injected into the motor magnetic chain and the rotationspeed observer, the induction motor driven by an induction motor speed sensorless drive control system is guaranteed to output 150% rated torque while running with low synchronous speed and running without synchronous speed, and can keep stability of the rated torque for long time.

The invention discloses a multi-step model forecast control method of a linear induction motor. The forecast control method comprises the following steps of (1) acquiring a state variable and an angular speed of the linear induction motor; (2) solving an optimal value of an input voltage vector of the motor under a non-constraint condition; (3) judging whether the optimal value conforms to a voltage constraint condition or not, if yes, entering step (5), otherwise entering step (4); (4) updating the optimal value by conforming to the voltage constraint condition as a target; (5) judging whether the optimal value conforms to a current constraint condition or not, if yes, entering step (7), otherwise entering step (6); (6 ) updating the optimal value by conforming to the current constraint condition as a target; and (7) calculating a duty ratio of a three-phase bridge arm according to the optimal value of the input voltage vector of the motor, and sending the duty ratio to an inverter to modulate a working condition of the motor. A multi-step model forecast control algorithm is applied to the linear induction motor, and the running performance of the linear induction motor is improved.