Patent
Variable frequence drive and rotation speed searching apparatus for an induction motor
Hui-Chung Hsieh,Chi-lung Hsiao +1 more
TLDR
In this article, the rotational speed of an induction motor is estimated by scanning the rotor frequency of the induction motor and determining either the error between a detected DC-bus voltage and a set DCbus voltage, or the discrepancy between the detected output current and the set output current, so that the rotation speed can be searched out.Abstract:
Provided is a variable frequency drive and a rotation speed searching apparatus for an induction motor incorporated therein. The rotation speed searching apparatus is featured by scanning the rotor frequency of the induction motor and determining either the error between a detected DC-bus voltage and a set DC-bus voltage or the error between a detected output current and a set output current, so that the rotation speed of the induction motor can be searched out.read more
Citations
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Patent
DC-Bus Controller for an Inverter
TL;DR: In this paper, a mean value calculator is used to calculate the mean value of the DC-bus voltage or current, which is used as a feedback signal in a closed-loop of the voltage and current source inverter controller.
Patent
Motor speed control with speed foldback for phase imbalance protection
TL;DR: In this article, a variable frequency motor drive consisting of a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power is described.
Patent
System for operating a three-phase variable frequency drive from an unbalanced three-phase or single-phase ac source
TL;DR: In this paper, a variable frequency motor drive consisting of a converter including a rectifier having an input for connection to an AC power source and converting the AC power to DC power is described.
Patent
Motor drive system and method
TL;DR: In this paper, a motor drive and a method of controlling a motor are provided, which includes a controller generating a motor reference voltage; a DC bus providing a DC voltage having a ripple; an inverter including power switches operable to convert the DC voltage into an AC motor voltage by modulating the power switches during a plurality of switching cycles, the AC motor voltages based on the motor voltage, a capacitor circuit coupled to the DC bus and having a maximum capacitance that is less than 10 microfarads per ampere of a rated current; and voltage prediction logic
References
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Patent
Slip control based on sensing voltage fed to an induction motor
TL;DR: In this article, an electronic motor drive for vector control of an induction motor controls slip and operating frequency in response to changes in stator voltage, and the drive includes a torque control loop, a flux control loop and a frequency control loop.
Patent
Synchronous motor driving system and sensorless control method for a synchronous motor
TL;DR: In this article, an axial error calculation unit is provided for estimating axial errors between a d-q axis and a dc-qc axis by using Ld, Lq, Ke, Id*, Iq*, Idc and Iqc in a range of all rotational speeds.
Patent
Voltage and current limiting method and apparatus for a voltage/frequency drive
Luis J. Garces,Timothy M. Rowan +1 more
TL;DR: In this article, a method and apparatus for maintaining both a DC bus voltage and a motor current within limit values was proposed, where, when a voltage limit condition occurs, a voltage error (i.e. motor current limit minus motor current) is used to reduce inverter output frequency until the current limit condition subsides.
Patent
Apparatus for and method of compensating for an output voltage error in an inverter output
Mikami Nobuhiro,Morohoshi Toshio +1 more
TL;DR: In this paper, the polarity of output current from an inverter used to change DC power into AC power is determined by setting the threshold current values higher than the ripples occurring at the zero current value.
Patent
Beat-less controller for permanent magnet motor
TL;DR: In this article, a DC-voltage pulsating frequency is estimated from a pulsing frequency setting calculated from the power supply frequency of an AC voltage and the detected current values of the inverter.