A field orientation control system for an interior permanent magnet synchronous motor includes function generating means responsive to a torque command signal for producing direct and quadrature axis direct current signals which are converted to synchronously-varying two-phase signals for coupling to power control means, for effecting sinusoidal energization of the permanent magnet motor. The function generators modify the torque command signal as a predetermined function of the motor parameters. Rotor position information is derived from measured stator voltages and currents without the use of a separate rotor position sensor. The control system includes means for establishing a preselected amplitude of a stator α-axis current in the motor at start-up prior to establishing orthogonal β-axis current such that the motor rotor is caused to become initially aligned with the selected α-axis.

Field orientation control of a permanent magnet motor

A pulse width modulation controller for a variable speed variable torque electric motor Inputs to the controller are a desired RPM signal, a motor electrical signal which is a function of the RPM of the rotor of the motor and its angular position relative to the stator, and a torque feed back signal derived from the power phase winding circuits of the motor The controller produces pulse width modulated power drive signals which are applied to power switches of the power phase winding circuits of the motor to allow electric current to flow through the power phase winding circuits when power phase enables signals produced by the controller sequentially enabling the power switch of a power phase winding circuit to do so The duty cycle of the power drive signals is a function of the difference between the desired and actual RPM of the motor and the torque of the motor The frequency of the power drive signals is a fixed integral multiple of the frequency of the power phase enable signals over the full operating range of RPMs of the motor

Pulse width modulating motor controller

An induction motor drive uses direct vector control for zero speed start up. According to the invention, a speed sensorless induction motor is controlled at all speeds, including zero or substantially zero speed, using direct vector control. In order to utilize direct vector control at all speeds, it is necessary to derive accurate stator flux vectors at all speeds. This is accomplished in the present invention by calculating two sets of stator flux vectors in diverse manners. A first set of flux vectors is derived from measured stator terminal voltage quantities, and a second set of flux vectors is derived from measured stator current quantities. The first set of flux vectors is valid at non-zero speed and the second set of flux vectors is valid at substantially zero speed. The direct vector control utilizes one of the two sets of flux vectors in accordance with predetermined criteria indicative of zero and non-zero speed conditions.

Zero speed start-up for a speed sensorless induction motor drive

L'invention se rapporte a un systeme de commande pour moteurs a induction a courant alternatif, qui comprend un stator, un rotor, au moins deux enroulements de stator et deux enroulements de rotor. The invention relates to a control system for AC motors induction, which comprises a stator, a rotor, at least two stator windings and two rotor windings. Ce systeme de commande comprend un premier rotateur vectoriel servant a mettre en rotation des signaux de commande selon un premier angle (alpha), en vue de produire des signaux de sortie connectes a des inverseurs de frequence destines a fournir des signaux d'entrainement a chaque enroulement de stator du moteur, le premier angle (alpha) constituant l'integrale de temps d'une frequence de rotation (w). This control system comprises a first vector rotator for rotating the control signals at a first angle (alpha), for producing output signals connected to frequency inverters for providing drive signals to each motor stator winding, the first angle (alpha) forming the time integral of a rotation frequency (w). Ce systeme de commande comprend en outre un second rotateur vectoriel servant a mettre en contre-rotation les tensions et/ou les courants d'entrainement mesures selon un second angle (-alpha) qui est l'inverse du premier angle (alpha). This control system further comprises a second vector rotator serving to tension against rotation and / or the drive currents measured at a second angle (-alpha) which is the inverse of said first angle (alpha). La frequence de rotation (w) est commandee en fonction de ces tensions et/ou courants mesures en contre-rotation, essentiellement en vue de maintenir l'amplitude des courants de magnetisation (Im) de chaque enroulement de stator a un niveau constant, ce qui constitue une condition necessaire pour permettre d'obtenir une orientation en champ naturel. Rotation frequency (w) is controlled in dependence of these voltages and / or currents measured against rotation, essentially for maintaining the amplitude of the magnetizing currents (Im) of each stator winding at a constant level, which is a necessary condition for obtaining an orientation in natural field.

Method and apparatus for controlling an ac induction motor by indirect measurement of the air-gap voltage.

The rectified (R,C) AC input is connected to the motor (M) through an inverter (O) with bridge-connected transistors (S). A shunt (Sh) in the DC bus (B) passes current-related signals (Idc) to a processor (CE) which also receives transistor state data (Sa, Sb, Sc), allowing it to reconstruct the individual phase currents. Using an applied speed setting, it issues control signals to the PWN controller (CC). When one, or both, output vector components fall below a preset value, it, or they, are increased by that value, and applied during the first PWM half-period. A second vector, applied in the second half-period, produces a mean equal to the unadjusted value. Current measurements are made only during the first half-period. Two variants, avoiding PWM asymmetry, are described.

Frequency converter for AC motor

A drive for a rotating field machine which has two AC voltage integrators of identical design for forming two electric voltage signals each of which is proportional to a flux component in the machine Each voltage integrator includes an integrator and a zero-controller having negative feedback for suppressing the DC component of input voltages fed to a summing point of the integrator Each integrator, is fed, as one input voltage, a voltage proportional to the phase-voltage belonging to the flux component and a voltage proportional to the corresponding stator current in a machine supply lead, for compensating the ohmic stator voltage drop A second voltage, also depending on the phase current, is processed to compensate for the inductive stator voltage drop To ensure optimum converter and machine utilization over an increased speed control range by reducing the phase errors of the determined flux components, each zero-controller includes a proportional controller and an integrated controller having output signals fed to the summing point The output signal of the integrator, corrected for the ohmic stator voltage drop and the inductive stray voltage, is fed, weighted proportionally to the frequency of the machine, to the input of the proportional controller, and weighted proportionally to the square of the frequency, to the input of the integrated controller, the weighting factor having a maximum value of 1

Rotating field machine drive and method

For forming an electric voltage signal which is proportional to a flux component of a rotating-field machine, a voltage associated with the flux component is fed to the input of an integrator, and a voltage signal proportional to the flux component is taken off of the integrator. The input of a zero-controller for suppressing the DC component of this voltage signal is connected to the output of the integrator and the output of the zero-controller is connected to a summing point at the input of the integrator. This integrator circuit can be used to determine the position of the flux of a rotating field machine, with the correct phase and amplitude, and independently of frequency, while the zero-controller remains engaged at speeds from the beginning of localization of standing rotor position up to the nominal frequency of the machine. The zero-controller has a P-controller and an I-controller whose output signals are fed to the summing point. The output signal of the integrator, weighted in proportion to the frequency of the machine, is fed to the input of the P-controller and, weighted in proportion to the square of the frequency, is fed to the input of the I-controller, the weighting factor having a maximum value of one. The circuit constitutes an AC voltage integrator having a characteristic frequency which depends on the frequency of the rotating field machine, the intercept frequency and the attenuation remaining constant. The phase error remains constant over the entire speed range of the rotating field machine.

Circuit for generating an electric signal proportional to a flux component of a rotating-field machine

Drehfeldmaschinenantrieb,bestehend aus einer umrichtergespeisten Drehfeldmaschine,insbesondere Synchronmaschine und einer Stromrichtersteuerung fuer den eigengetakteten,insbesondere feldorientierten Betrieb dieser Maschine,mit zwei baugleichen Wechselspannungsintegratoren und Verfahren zum Betrieb des Dre

Weigel Wolf-Dieter Dr-Ing

Papers

Rotating field machine drive and method

Circuit for generating an electric signal proportional to a flux component of a rotating-field machine

Schaltungsanordnung zur Bildung eines elektrischen Spannungssignals,das einer Flusskomponente in einer Drehfeldmaschine proportional ist