US 6,784,634 B2Granted

Brushless doubly-fed induction machine control

OwnerEdwin A. Sweoinventor

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Abstract

Processor-based field oriented control for brushless doubly-fed induction machine having first and second polyphase stator windings is programmed to operate the machine in various modes, as a motor or a generator, with bumpless switching between operating modes. An electronic power converter controls a current supplied to the first stator winding to control the torque of the machine, with the second stator winding selectively connected to an AC line. Stationary coordinates for in-phase and quadrature current commands are coordinate transformed using a voltage vector for voltage induced on the first polyphase stator winding to control current in the first stator winding, with or without a position sensor. The electronic power converter controls the voltage supplied to the first stator for generating, with the second stator selectively connected to a load. The machine can also be controlled to operate as a singly-fed motor at lower speeds, with the second stator winding shorted.

Claims32

Dependent claims

A method of field oriented control for substantially independently controlling an excitation current and a torque producing current of a doubly-fed induction machine having a first polyphase stator winding and a second polyphase stator winding that are substantially electrically and magnetically independent, and a brushless induction rotor assembly that magnetically couples the first and the second polyphase stator windings in a reverse phase sequence, wherein a desired excitation current and a desired torque producing current in one polyphase stator winding are defined in stationary coordinates by a quadrature current command and an in-phase current command, respectively, the method comprising the steps of:

(a) coupling the first polyphase stator winding to a polyphase electronic power converter having a power input connected to an alternating current (AC) line, and coupling the second polyphase stator winding to the AC line;
(b) monitoring currents in at least two phases of the first polyphase stator winding and in at least one phase of the second polyphase stator winding;
(c) monitoring a voltage of at least one phase of the AC line;
(d) as a function of the currents that are monitored in step (b) and as a function of the voltage of the AC line monitored in step (c), calculating an angle of one of:
(i) a voltage vector induced on the first polyphase stator winding by the AC line;
and
(ii) a flux vector in the first polyphase stator winding caused by the AC line, said flux vector lagging the voltage vector by 90 electrical degrees;
and
(e) coordinate transforming an in-phase command and a quadrature command, using the angle of step (d), to produce polyphase commands that are supplied to the polyphase electronic power converter, said polyphase commands causing the polyphase electronic power converter to maintain a torque producing component vector of the current in the first polyphase stator winding substantially proportional to the in-phase current command and substantially in one of a zero degree and a 180 degree relationship with the voltage vector of step (d), as required to produce a desired torque and to maintain an excitation component vector of current in the first polyphase stator winding substantially in quadrature with the voltage vector of step (d).

6 more elements

A field oriented control for a doubly-fed induction machine having a first polyphase stator winding and a second polyphase stator winding that are substantially electrically and magnetically independent, and a brushless induction rotor assembly that magnetically couples the first polyphase stator winding to the second polyphase stator winding in reverse phase sequence, said second polyphase stator winding being coupled to an alternating current (AC) line, comprising:

(a) an electronic power converter adapted to couple to the first polyphase stator winding and to the AC line;
(b) current inputs adapted to couple to current transducers that monitor currents in at least two phases of the first polyphase stator winding and in at least one phase of the second polyphase stator winding;
(c) a voltage input adapted to couple to a voltage transducer that monitors a voltage of at least one phase of the AC line;
(d) memory in which a plurality of machine instructions are stored;
and
(e) a processor coupled to the memory, said processor executing the machine instructions to cause the processor to carry out a plurality of functions, including:
(i) calculating an angle of one of a voltage vector and a flux vector induced on the first polyphase stator winding by the AC line, as a function of the currents that are monitored by the current transducers and as a function of the voltage of the AC line monitored by the voltage transducer;
and
(ii) coordinate transforming an in-phase command and a quadrature command in stationary coordinates, using the angle of step (i), to produce polyphase commands that are supplied to the polyphase electronic power converter, said polyphase commands causing the polyphase electronic power converter to maintain a torque producing component vector of the current in the first polyphase stator winding substantially proportional to an in-phase current command and substantially in one of a zero degree and 180 degree relationship with the voltage vector of step (i), as required to produce a desired torque, and to maintain an excitation component vector of current in the first polyphase stator winding substantially in quadrature with the voltage vector of step (i).

6 more elements

A method for generating variable speed constant frequency power with a doubly-fed induction generator that is driven by an engine, said generator having a polyphase first stator winding and a second stator winding that are substantially electrically and magnetically independent, and a brushless induction rotor assembly that magnetically couples the first and second stator windings in a reverse phase sequence, the method comprising the steps of:

(a) coupling the polyphase first stator winding to a first set of AC power connections of an electronic power converter configured to operate as a variable voltage, variable frequency inverter, and coupling the second stator winding to a second set of AC power connections of the electronic power converter, said second stator winding also being selectively coupled to the load;
(b) monitoring at least one phase of the second stator winding to produce signals indicative of one of:
(i) a voltage and a frequency of said at least one phase;
and
(ii) a voltage and an electrical position of said at least one phase;
(c) regulating a frequency of a voltage applied by the electronic power converter to the first stator winding so that the frequency of said at least one phase on the second stator winding is substantially constant;
(d) regulating a voltage applied to the first stator winding by the electronic power converter so that the voltage on the second stator winding is substantially constant;
(e) monitoring a current in at least one phase of one of the first stator winding and the second stator winding of said generator;
and
(f) controlling a speed of the engine in response to the current that is monitored, the engine thereby driving said generator at a speed sufficient to meet the load coupled to the second stator winding of said generator.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/238,428Filed 9 Sep 2002 · us provisional application
Priority: 14 Sep 2001
Published: US 2003/0052643 A120 Mar 2003
Granted: 31 Aug 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H02P 21/141
Estimation or adaptation of machine parameters, e.g. flux, current or voltage: flux estimation
H02P 9/007
Arrangements for controlling electric generators for the purpose of obtaining a desired output: control circuits for doubly fed generators
H02P 21/34
Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation: arrangements for starting
H02P 2101/15
Special adaptation of control arrangements for generators: for wind-driven turbines

Family

Application60/322,201Us provisional application · filed 14 Sep 2001
Application60/347,822Us provisional application · filed 23 Oct 2001
Application60/348,520Us provisional application · filed 16 Jan 2002
US 2003/0052643 A1Pre-grant publication · published 20 Mar 2003
US 6,784,634 B2This patent

From the US filing history. Foreign family members aren’t listed.