Back to results
US 5,959,430 AGranted
Power conversion system
AssigneeKabushiki Kaisha Toshiba
InventorsKazuaki Yuki, Yosuke Nakazawa
Life of this patent
Estimating the term…
Abstract
A power conversion system, including a converter for converting an AC power from a power source to a DC power, a DC capacitor for smoothing the DC power output from the converter, an inverter for converting the DC power smoothed by the DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor, a unit for detecting or computing a magnetic flux axis of the induction motor, a unit for computing a current orthogonal to the detected or computed magnetic flux axis, and a phase control unit for controlling a phase angle of an output voltage of the inverter so that a value of the current orthogonal to the detected or computed magnetic flux axis is maintained at a constant level.
Claims28
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- a DC capacitor for smoothing said DC power output from said converter;
- a voltage inverter for converting said DC power smoothed by said DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor;
- means for obtaining a magnetic flux axis of said induction motor;
- means for computing a current orthogonal to said obtained magnetic flux axis;
- and
- phase control means for controlling a phase angle of an output voltage of said inverter so that a value of said current orthogonal to said obtained magnetic flux axis is maintained at a constant level.
4 more elements
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- a DC capacitor for smoothing said DC power output from said converter;
- a voltage inverter for converting said DC power smoothed by said DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor;
- vector control means for controlling a vector on a dq-axis rotatory coordinate system where an axis agreed with a magnetic flux axis of said induction motor is assumed to be a d-axis and an axis orthogonal to said d-axis is assumed to be a q-axis;
- means for obtaining a q-axis component current;
- and
- phase control means for controlling a phase angle of an output voltage of said inverter so that a value of said obtained q-axis component current is maintained at a constant level.
4 more elements
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- a DC capacitor for smoothing said DC power output from said converter;
- a voltage inverter for converting said DC power smoothed by said DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor;
- means for obtaining an output torque of said induction motor;
- and
- phase control means for controlling a phase angle of an output voltage of said inverter so that a value of said obtained output torque is maintained at a constant level.
3 more elements
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- a DC capacitor for smoothing said DC power output from said converter;
- an inverter for converting said DC power smoothed by said DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor;
- vector control means for controlling a vector on a dq-axis rotatory coordinate system where an axis agreed with a magnetic flux axis of said induction motor is assumed to be a d-axis and an axis orthogonal to said d-axis is assumed to be a q-axis;
- means for obtaining a q-axis component current;
- means for computing a q-axis primary current command value;
- means for computing a difference between said obtained q-axis component current value and said computed q-axis primary current command value;
- and
- phase control means for controlling a phase angle of an output voltage of said inverter so that said computed difference becomes zero.
6 more elements
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- a DC capacitor for smoothing said DC power output from said converter;
- an inverter for converting said DC power smoothed by said DC capacitor to an AC power of an arbitrary frequency to drive and control an induction motor;
- vector control means for controlling a vector on a dq-axis rotatory coordinate system where an axis agreed with a magnetic flux axis of said induction motor is assumed to be d-axis and an axis orthogonal to said d-axis is assumed to be q-axis;
- means for obtaining a q-axis component current;
- and
- means for controlling an output frequency of said inverter so that a value of said obtained q-axis component current is maintained at a constant level.
4 more elements
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- and
- vector control means for adjusting an AC voltage vector output by said inverter so that a state quantity arising from rectification by said converter becomes constant while a magnetic flux component current is pulsating on a rotatory coordinate system composed of a magnetic flux axis and a torque axis orthogonal to said magnetic flux axis according to fluctuation of said DC power output from said converter.
1 more element
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- and
- vector control means for adjusting a phase angle from a magnetic flux axis to an AC voltage vector output by said inverter so that a state quantity arising from rectification by said converter becomes constant while a magnetic flux component current is pulsating on a rotatory coordinate system composed of said magnetic flux axis and a torque axis orthogonal to said magnetic flux axis according to fluctuation of said DC power output from said converter.
1 more element
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- and
- vector control means for adjusting an output frequency of said inverter so that a state quantity arising from rectification by said converter becomes constant while a magnetic flux component current is pulsating on a rotatory coordinate system composed of a magnetic flux axis and a torque axis orthogonal to said magnetic flux axis according to fluctuation of said DC power output from said converter.
1 more element
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- and
- vector control means for adjusting a magnetic flux component voltage and a torque component voltage so that a torque component current becomes constant while a magnetic flux component current is pulsating on a rotatory coordinate system composed of a magnetic flux axis and a torque axis orthogonal to said magnetic flux axis according to fluctuation of said DC power output from said converter.
1 more element
A power conversion system, comprising:
- a converter for converting an AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- and
- vector control means for adjusting a magnetic flux component current so that said magnetic flux component current pulsates on a rotatory coordinate system composed of a magnetic flux axis and a torque axis orthogonal to said magnetic flux axis according to fluctuation of said DC power output from said converter.
1 more element
A power conversion system, comprising:
- a converter for converting a single-phase AC power from a power source to a DC power;
- an inverter for converting said DC power output by said converter to an AC power of an arbitrary frequency to drive and control an induction motor;
- means for obtaining a secondary magnetic flux mean value (.phi.2*) of said induction motor;
- means for obtaining a phase angle (.rho.) from a secondary magnetic flux axis of said induction motor to an output voltage axis;
- torque current computing means for computing a mean value (iq*) of a torque current orthogonal to said secondary magnetic flux axis;
- magnetic flux frequency computing means for computing a secondary magnetic flux frequency (.omega.o) which is given to said induction motor;
- means for obtaining a DC link voltage (Vdc) at an output side of said converter and an input side of said inverter;
- means for computing a DC link voltage fluctuation quantity (.DELTA.Vdc) from a mean value of said DC link voltage (Vdc);
- means for obtaining a rotating frequency (fr) and an angular frequency (.omega.r) of said induction motor;
- means for computing an inverter frequency reference (fi*) based on said rotating frequency (fr) and a slip angular frequency reference (fs*) of said induction motor;
- means for obtaining an inverter phase angle reference (.theta..sub.i *) by integrating said inverter frequency reference (fi*);
- means for obtaining a compensation value (.DELTA..theta.i) to an inverter phase angle (.theta.i) based on the following Equations (1A)-(4A) by inputting said motor rotating frequency (fr), said motor angular frequency (.omega.r), said DC link voltage fluctuation quantity (.DELTA.Vdc), said phase angle (.rho.), a Laplace operator, said DC link voltage (Vdc), said secondary magnetic flux angular frequency (.omega.o), a transfer function (H1(s)), a motor primary resistance (R1), a motor secondary resistance (R2), a motor primary self-inductance (L1), a motor secondary self-inductance (L2) and a mutual inductance (M) ##EQU36##
- c2=cos.rho.
- c1=a1cos.rho.+b1sin.rho.
- c0=a0cos.rho.+b0sin.rho.
- d2=-sin.rho.
- d1=b1cos.rho.-a1sin.rho.
- d0=b0cos.rho.-a0sin.rho. (3A) ##EQU37## means for obtaining said inverter phase angle (.theta.i) by adding said compensation value (.DELTA..theta.i) and said inverter phase angle reference (.theta.i*):
- and
- means for controlling said inverter output voltage based on said inverter phase angle (.theta.i).
17 more elements
Dependencies are inferred from the claim text.