502 results about "Linear induction motor" patented technology

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.

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 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.

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.

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 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 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.

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 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.