Parasynchronous induction motor control method and apparatus

• US 5,780,990 A
• Filed: 03/06/1997
• Issued: 07/14/1998
• Est. Priority Date: 03/06/1997
• Status: Expired due to Fees

• Current Assignee: Harold J. Weber
• Original Assignee: Harold J. Weber
• Inventors: Weber, Harold J.
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US08/813,791
• Time in Patent Office: 495 Days
• Field of Search: 318/727, 318/772-777, 318/798-815, 318/729, 318/767-771, 318/61-82, 318/720-724, 318/437, 318/438
• US Class Current: 318/807
• CPC Class Codes: H02P 27/02 using supply voltage with constant frequency and variable amplitude

Abstract

Alternating current electric induction motor operating from a source of AC electric power is driven at a parasynchronous rate of field collapse and magnetic flux reversal which is derived from the immediate train of alternating half-wave power cycles supplied by the AC power source. The higher and lower rates of magnetic flux field reversal result in a corresponding higher or lower rate of magnetic flux field rotation than that which is ordinarily produced. In a subsynchronous operating mode, bicyclic half-cycles of AC power are polarity-paired through inversion of one of the component half-cycles and successive pairs are alternated in polarity, thereby parasynchronously decreasing the effective rotating magnetic flux field rate. In a suprasynchronous mode, individual AC power half-cycles are split into quarter-cycle quadrants and the quadrants are successively alternated in polarity, thereby parasynchronously increasing the effective rotating magnetic flux field rate. A novel induction motor construction having two parallel RUN windings, with each winding sequentially excited in opposite directions by the parasynchronous power pulses simplifies intercycle switching circuitry. Shaft speed of a common 2-pole AC motor which ordinarily runs just shy of 3,600 RPM from 60 Hertz AC power now runs pseudosynchronously runs shy of 1,800 RPM in the subsynchronous mode and near 7,200 RPM in the suprasynchronous mode.

Claims

1. Parasynchronous control method for an electric induction motor comprising steps of:

securing circuit coupling with a source of prime frequency alternating current (AC) electric power comprising a continuum of bipolar AC power cycles implicating a first polarity half-cycle power signal portion alternating with a second polarity half-cycle power signal portion;

quadrisecting the bipolar AC power cycle whereby the first polarity half-cycle power signal portion is bisected into a first power signal quadrant portion and the second power signal quadrant portion, and the second polarity half-cycle portion signal portion is bisected into a third power signal quadrant portion and a fourth power signal quadrant portion;

selective first polarity coupling of the first power signal quadrant portion and the third power signal quadrant portion with a field excitation winding of an AC induction motor to establish a first magnemotive direction of current flow therethrough;

selective second polarity coupling of the second power signal quadrant portion and the fourth power signal quadrant portion with the field excitation winding to establish a second magnemotive direction of current flow therethrough; and

,

reversing the field excitation winding'"'"'s induced sense of NORTH and SOUTH pole magnetic field polarity at a suprafrequency rate in response to a nexus of quadrant by quadrant alternation of said first magnemotive direction of current flow and said second magnemotive direction of current flow;

whereby, an induced parasynchronous motor output member rotational speed is obtained in a frequency-cum-rotation suprasynchronous range between;

space="preserve" listing-type="equation">RPM>

1.5×

((PLF×

60)/NP)

and

space="preserve" listing-type="equation">RPM<

2×

((PLF×

60)/NP)

where;

PLF=AC electric power source prime line frequency, Hertz;

NP=Number of motor field poles,

RPM=Motor output member speed.

2. The parasynchronous control method of claim 1 wherein the selective first polarity coupling and the selective second polarity coupling comprises further steps of:

configuring the field excitation winding to include a first field winding portion and a second field winding portion with each field winding portion inducing a similar flux level of magnetic strength in the induction motor'"'"'s field pole structure;

a first switching of a flow of the first power signal quadrant portion through the first field winding portion to establish a first pole magnetic sense in the induction motor'"'"'s field pole structure;

a second switching of a flow of the second power signal quadrant portion through the second field winding portion to establish a second pole magnetic sense in the induction motor'"'"'s said field pole structure;

a third switching of a flow of the third power signal quadrant portion through the second field winding portion to establish the first pole magnetic sense in the induction motor'"'"'s said field pole structure; and

,

a fourth switching of a flow of the fourth power signal quadrant portion through the first field winding portion to establish the second pole magnetic sense in the induction motor'"'"'s said field pole structure.

3. The parasynchronous control method of claim 1 wherein the selective first polarity coupling and the selective second polarity coupling comprises further steps of:

converting the continuum of bipolar AC power cycles into a continuum of unipolarity power quadrants of said half-cycle power pulse signals comprising a unipolarity nexus of the first power signal quadrant portions through the fourth power signal quadrant portions;

configuring the field excitation winding to include a first field winding portion and a second field winding portion with each field winding portion inducing a similar flux level of counterpolar magnetic strength in the induction motor'"'"'s field pole structure;

a first switching of a flow of the first power signal quadrant portion of the nexus through the first field winding portion to establish a first pole magnetic sense in the induction motor'"'"'s field pole structure;

a second switching of a flow of the second power signal quadrant portion of the nexus through the second field winding portion to establish a second pole magnetic sense in the induction motor'"'"'s said field pole structure;

a third switching of a flow of the third power signal quadrant portion of the nexus through the first field winding portion to establish the first pole magnetic sense in the induction motor'"'"'s said field pole structure; and

,

a fourth switching of a flow of the fourth power signal quadrant portion of the nexus through the second field winding portion to establish the second pole magnetic sense in the induction motor'"'"'s said field pole structure.

4. The parasynchronous control method of claim 1 wherein the partitioning step comprises further steps of:

sensing AC power factor of the AC induction motor;

determining an increase in phase angle duration of the first power signal quadrant portion and third power signal quadrant portion relative with a corresponding decrease in the duration of the second power signal quadrant portion and fourth power signal quadrant portion in response to a first factorial change in the sensed AC power factor; and

,

determining a decrease in the phase angle duration of the first power signal quadrant portion and the third power signal quadrant portion relative with a corresponding increase in the duration of the second power signal quadrant portion and fourth power signal quadrant portion in response to a second factorial change in the sensed AC power factor.

5. The parasynchronous control method of claim 1 comprising further steps of:

winding the field excitation winding as two electrically separate winding portions;

inductively coupling the two winding portions to develop an equivalent strength of magnetic field flux in a stator pole structure of the electric induction motor;

securing said selective first polarity coupling with a first section of the two electrically separate winding portions;

phasing said selective first polarity coupling to develop an alternating NORTH and SOUTH sense of induced magnetic field in the stator pole structure;

securing said selective second polarity coupling with a second section of the two electrically separate winding portions;

phasing said selective second polarity coupling to develop an inversely alternating SOUTH and NORTH sense of said induced magnetic field in the stator pole structure.

6. The parasynchronous control method of claim 5 including at least two distinct parasynchronous speeds of operation and comprising further steps of:

disabling the selective first polarity coupling and the selective second polarity coupling with the two electrically separate winding portions;

arranging a electrical circuit coupling the two winding portions to additively complement field strength of the magnetic field flux developed in the stator pole structure of the electric induction motor;

securing a energizing cooperation between the two winding portions and the source of prime frequency alternating current (AC) electric power;

thereby obtaining the induced parasynchronous motor output member rotational speed in a frequency-cum-rotation near synchronous range between;

space="preserve" listing-type="equation">RPM>

0.75×

((PLF×

60)/NP)

and

space="preserve" listing-type="equation">RPM<

1×

((PLF×

60)/NP)

where;

PLF=AC electric power source prime line frequency, Hertz;

NP=Number of motor field poles,

RPM=Motor output member speed.

7. Parasynchronous control method for an induction motor comprising the steps of:

securing circuit coupling with a source of prime frequency alternating current (AC) electric power comprising a continuum of bipolar AC power cycles implicating a first polarity half-cycle power signal portion alternating with a second polarity half-cycle power signal portion;

partitioning the bipolar AC power cycles into a nexus signal of bicyclic power signal clusters of alternating polarity half-cycle portions including a first polarity first half-cycle portion, a second polarity second half-cycle portion, a first polarity third half-cycle portion, and a second polarity fourth half cycle portion;

a determining of recurrent states of a normal sense polarity coupling of the first half cycle portion and an inverse sense polarity coupling of the second half cycle portion of the bicyclic power signal cluster with a field excitation winding of an AC induction motor to thereby establish a first magnemotive direction of current therethrough;

the determining of recurrent states of an inverse sense polarity coupling of the third half cycle portion and a normal sense polarity coupling of the fourth half cycle portion of the bicyclic power signal cluster with the field excitation winding of the AC induction motor to thereby establish a second magnemotive direction of current flow therethrough;

alternating the field excitation winding'"'"'s induced sense of NORTH and SOUTH pole magnetic field polarity at a virtual subfrequency rate in response to the determination of pairs of virtual like-polarity half cycle portions of the bicyclic power signal clusters; and

,

whereby the virtual subfrequency rate of the reversal of the field excitation winding develops an induced subsynchronous rate of rotating magnetic field relative with a stator field pole structure portion of the AC induction motor and encourages a parasynchronous rate of motor output member rotational speed in a frequency-cum-rotational subsynchronous range between;

space="preserve" listing-type="equation">RPM>

0.375×

((PLF×

60)/NP)

and

space="preserve" listing-type="equation">RPM<

0.5×

((PLF×

60)/NP)

where;

PLF=AC electric power source prime line frequency, Hertz;

NP=Number of motor stator field poles,

RPM=Motor output member speed.

8. The parasynchronous control method of claim 7 wherein the determining of recurrent states of the bicyclic power signal cluster said coupling with the field excitation winding comprises further steps of:

configuring the field excitation winding to include a first field winding portion and a second field winding portion with each winding portion inducing a substantive level of counter-polar magnetic flux field strength in the stator field pole structure;

a first switching of a flow of the first polarity first half-cycle portion of the nexus signal through the first field winding portion to establish a first pole magnetic sense in the stator pole structure;

a second switching of a flow of the second polarity second half-cycle portion of the nexus signal through the second field winding portion to establish a first pole magnetic sense in the stator pole structure;

a third switching of a flow of the first polarity third half-cycle portion of the nexus signal through the second field winding portion to establish the second pole magnetic sense in the stator pole structure; and

a fourth switching of a flow of the second polarity fourth half-cycle portion of the nexus signal through the first field winding portion to establish the second pole magnetic sense in the stator pole structure.

9. The parasynchronous control method of claim 7 wherein the determining of recurrent states of the bicyclic power signal cluster said coupling with the field excitation winding comprises further steps of:

converting the partitioned said bicyclic power signal clusters into a tetrapulsative succession of unipolar half-cycle power pulses;

configuring the field excitation winding to include a first field winding portion and a second field winding portion with each winding portion inducing a coequal level of counterpolar magnetic flux field strength in the stator field pole structure;

a first power flow switching of a biquadrantal first half-cycle portion of the bicyclic power signal cluster of unipolar half-cycle power pulses through the first field winding portion to establish a first field pole magnetic sense in the stator field pole structure;

a second power flow switching of a biquadrantal second half-cycle portion of the bicyclic power signal cluster of unipolar half-cycle power pulses through the first field winding portion to maintain the first field pole magnetic sense in the stator field pole structure;

a third power flow switching of a biquadrantal third half-cycle portion of the bicyclic power signal cluster of unipolar half-cycle power pulses through the second field winding portion to alternately establish a second field pole magnetic sense in the stator field pole structure; and

,

a fourth power flow switching of a biquadrantal fourth half-cycle portion of the bicyclic power signal cluster of unipolar half-cycle power pulses through the first field winding portion to maintain the second field pole magnetic sense in the stator field pole structure.

10. The parasynchronous control method of claim 7 wherein the driving of the field excitation windings obtain equivalence of the polarity inversion of the second half-cycle portion and the polarity inversion of the third half-cycle portion of the bicyclic power signal cluster through including the steps of:

structuring the field excitation windings to include a first field winding portion and a second field winding portion with each configuratively wound to induce a coequal level and transposed polar sense of magnetic field flux in the induction motor'"'"'s said stator pole structure;

steering flow of the first half-cycle portion and the fourth half-cycle portion to flow through the first field winding portion thereby producing a normal polar sense of NORTH and SOUTH said magnetic field flux in the stator pole structure; and

steering flow of the second half-cycle portion and the third half-cycle portion to flow through the second field winding portion thereby producing a transposed polar sense of SOUTH and NORTH said magnetic field flux in the stator pole structure.

11. The parasynchronous control method of claim 7 comprising further steps of:

winding the field excitation winding as two electrically separate winding portions;

configuring the two winding portions to develop an equivalent strength of magnetic field flux in the stator field pole structure of the electric induction motor;

a determining of recurrent states of a first polarity coupling said selective first polarity coupling with a first section of the two electrically separate winding portions;

phasing said selective first polarity coupling to develop an alternating NORTH and SOUTH sense of induced magnetic field in the stator field pole structure;

securing said selective second polarity coupling with a second section of the two electrically separate winding portions;

phasing said selective second polarity coupling to develop an inversely alternating SOUTH and NORTH sense of said induced magnetic field in the stator field pole structure.

12. The parasynchronous control method of claim 7 comprising further steps of:

winding the field excitation winding as two electrically separate winding portions;

configuring each of the two winding portions to develop a similar level of magnetic field flux in the stator field pole structure of the electric induction motor;

securing a first coupling of the first half cycle portion and the fourth half cycle portion of the cluster with a first section of the two electrically separate winding portions;

phasing said first coupling to develop a normal NORTH and SOUTH sense of induced magnetic flux field in the stator field pole structure;

securing a second coupling of the second half cycle portion and the third half cycle portion of the cluster with a second section of the two electrically separate winding portions; and

,

phasing said second coupling to develop a transposed SOUTH and NORTH sense of said induced magnetic flux field in the stator field pole structure.

13. The parasynchronous control method of claim 12 wherein a second near synchronous speed of operation may be obtained, therefor comprising further steps of:

disabling the first polarity coupling and the second polarity coupling with the two electrically separate winding portions;

arranging an electrical circuit coupling of the two winding portions to secure an additive complementation of said level of magnetic field flux developed in the stator pole structure by each of the two winding portions;

securing a energizing cooperation between the two winding portions and the source of prime frequency alternating current (AC) electric power; and

,

developing the motor output member rotational speed to occur in the frequency-cum-rotation and near synchronous range between;

space="preserve" listing-type="equation">RPM>

0.75×

((PLF×

60)/NP)

and

space="preserve" listing-type="equation">RPM<

1×

((PLF×

60)/NP)

where;

PLF=AC electric power source prime line frequency, Hertz;

NP=Number of motor stator field poles,

RPM=Motor output member speed.

14. Parasynchronous induction motor control method for producing an exceptional rate of rotational speed of an output member portion of an electric induction motor and comprising steps of:

securing coupling of the electric induction motor with a prime frequency source of alternating current (AC) electric power delivered as a consecution of quadrantal portions of AC electric power cycles;

switching of an instant quadrant-by-quadrant positive and negative polarity sense of the consecution of quadrantal portions relative with a predetermined pattern intently defining a virtual pseudofrequency rate;

whereby the virtual pseudofrequency rate of quadrantal polarity reversals of the consecution of quadrantal portions coupled with a field winding portion of the electric induction motor induces said exceptional rate of output member rotational speed in a frequency-cum-rotation parasynchronous range between;

space="preserve" listing-type="equation">RPM>

0.75×

((VPF×

60)/NP)

and

space="preserve" listing-type="equation">RPM<

2×

((VPF×

60)/NP)

where;

VPF=Virtual pseudofrequency rate of power signal quadrantal portion polarity reversals

NP=Number of motor stator field poles

RPM=Motor output member rotational speed.

15. The parasynchronous induction motor control method of claim 14 wherein the switching of an instant quadrant-by-quadrant positive and negative polarity sense of each successive power signal said quadrantal portion serves to intently develop the virtual pseudofrequency rate of the power signal quadrantal polarity reversals coupled with the field winding portion of the electric induction motor, including quadrantal polarity switching steps producing:

a normal polarity sense coupling of a first power signal quadrant portion;

an inverse polarity sense coupling of a second power signal quadrant portion

the inverse polarity sense coupling of a third power signal quadrant portion; and

,

the normal polarity sense coupling of a fourth power signal quadrant portion;

whereby a virtual suprafrequency recurrence of said virtual pseudofrequency VPF rate of field winding magnetic field flux reversals occur which may substantially increase the usual rate of motor output member rotational speed.

16. The parasynchronous induction motor control method of claim 14 wherein the predetermined pattern defining the virtual pseudofrequency rate comprises further steps of:

partitioning the AC electric power cycles into bicyclic clusters wherein each cluster comprises a series of four alternating polarity half-cycle portions including a nexus signal of eight quadrantal portions;

said switching instant quadrant-by-quadrant positive and negative polarity sense of each said consecutive quadrantal portion of the nexus signal to intently develop the virtual pseudofrequency rate as a consecution of quadrantal polarity reversals coupled with a field winding portion of the electric induction motor, therefor including quadrantal polarity switching steps producing;

a normal biquadrantal polarity sense coupling of a first half-cycle portion of the AC electric power cycle;

an inverse biquadrantal polarity sense coupling of a second half-cycle portion of the AC electric power cycle;

the inverse biquadrantal polarity sense coupling of a third half-cycle portion of the AC electric power cycle; and

,

the normal biquadrantal polarity sense coupling of a fourth half-cycle portion of the AC electric power cycle;

whereby a subfrequency recurrence of said virtual pseudofrequency VPF rate of the field winding induced magnetic field flux reversals occur which may substantially decrease the usual rate of motor output member rotational speed.

17. The parasynchronous induction motor control method of claim 14 comprising further steps of:

winding the field winding portion of the electric induction motor to include a first winding portion and a second winding portion with each winding portion configured to induce a similar level of magnetic flux field strength in a stator field pole structure of the electric induction motor;

phasing the first winding portion and the second winding portion to said induce an opposite polarity sense of said magnetic flux field strength;

directing current flow of a first power signal quadrant portion through the first field winding portion to said induce a normal magnetic field polarity sense in the stator field pole structure;

redirecting current flow of a second power signal quadrant portion through the second field winding portion to said induce an inverse magnetic field polarity sense in the stator field pole structure;

said redirecting current flow of a third power signal quadrant portion through the second field winding portion to said induce said normal magnetic field polarity sense in the stator field pole structure; and

,

said directing current flow of a fourth power signal quadrant portion through the first field winding portion to said induces said inverse magnetic field polarity sense in the stator field pole structure;

whereby, a suprasynchronous rate of magnetic field rotation develops about the stator field pole structure of the induction motor which encourages an inductively coupled rotor member to rotate at a rate about double that which may be conventionally obtained from the prime frequency source of AC electric power.

18. The parasynchronous induction motor control method of claim 14 comprising further steps of:

partitioning a profluence of the AC electric power cycles into bicyclic clusters of the consecutive quadrantal portions with each cluster comprising a nexus of four alternating polarity half-cycle portions including eight power signal quadrantal portions;

winding the field winding portion of the electric induction motor to include a first winding portion and a second winding portion with each winding portion configured to induce a similar level of magnetic flux field strength in a stator field pole structure of the electric induction motor;

phasing the first winding portion and the second winding portion to respectively said induce an opposite polarity sense of said magnetic flux field strength;

directing current flow of a first biquadrantal half-cycle portion through the first field winding portion to said induce a normal magnetic field polarity sense in the stator field pole structure;

redirecting current flow of a second biquadrantal half-cycle portion through the second field winding portion to maintain induction of the normal magnetic field polarity sense in the stator field pole structure;

said redirecting current flow of a third biquadrantal half-cycle portion through the second field winding portion to said induce an inverse magnetic field polarity sense in the stator field pole structure; and

,

said directing current flow of a fourth biquadrantal half-cycle portion through the first field winding portion to maintain induction of said inverse magnetic field polarity sense in the stator field pole structure,

whereby, a subsynchronous rate of magnetic field rotation develops about the stator field pole structure of the induction motor which encourages an inductively coupled rotor member to rotate at a rate about one-half that which may be conventionally obtained from the prime frequency source of AC electric power.

19. The parasynchronous induction motor control method of claim 14 comprising further steps of:

converting of the consecution of quadrantal portions into a nexus signal of quadrantal duration alternating direction of current flow which alternates twice relative with each AC electric power cycle and which flows through the field winding portion of the electric induction motor and therefor comprising;

switching of a first quadrantal portion of the nexus to produce a forward current flow through the field winding portion and induce a first magnetic flux field NORTH and SOUTH polar sense in a stator field pole structure of the electric induction motor;

switching of a second quadrantal portion of the nexus to produce a reverse current flow through the field winding portion and said induce a second magnetic flux field SOUTH and NORTH polar sense in the stator field pole structure;

switching of a third quadrantal portion of the nexus to produce a reverse current flow through the field winding portion and said induce the first magnetic flux field NORTH and SOUTH polar sense in the stator field pole structure;

switching of a fourth quadrantal portion of the nexus to produce a forward current flow through the field winding portion and said induce the second magnetic flux field SOUTH and NORTH polar sense in the stator field pole structure; and

,

developing a virtual suprafrequency excitation of the stator field pole structure in response to the nexus signal;

thereby, inducing of a suprasynchronous rate of said exceptional output member rotational speed.

20. The parasynchronous induction motor control method of claim 14 comprising further steps of:

treating the consecution of quadrantal portions as a consecution of bicyclic clusters comprising a nexus signal of fourth alternating polarity electric power biquadrantal half-cycle portions;

switching of a first said electric power biquadrantal half-cycle portion of the nexus signal to produce forward current flow through the field winding portion and induce a first direction of magnetic flux field NORTH and SOUTH polar sense in a stator field pole structure of the electric induction motor;

the switching of a second said electric power biquadrantal half-cycle portion of the nexus signal to produce reverse current flow through the field winding portion and continue to induce the first direction of magnetic flux field NORTH and SOUTH polar sense in the stator field pole structure;

the switching of a third said electric power biquadrantal half-cycle portion of the nexus signal to produce reverse current flow through the field winding portion and induce a second direction of magnetic flux field SOUTH and NORTH polar sense in the stator field pole structure;

the switching of a fourth said electric power biquadrantal half-cycle portion of the nexus signal to produce a forward current flow through the field winding portion and continue to induce the second direction of magnetic flux field SOUTH and NORTH polar sense in the stator field pole structure; and

,

developing a virtual subfrequency excitation of the stator field pole structure in response to the nexus signal;

thereby, inducing a subsynchronous rate of said exceptional output member rotational speed.

21. The parasynchronous induction motor control method of claim 15 wherein the substantially increased said motor output member rotational speed is utilized to operate an impeller portion of a centrifugal pump, comprising:

integrating the induction motor with a centrifugal pump coupling the motor output member with an impeller member of the centrifugal pump; and

,

spinning the impeller member at the suprasynchronous rate of said exceptional motor output member rotational speed delivered by the induction motor.