Displaced waveform for a pulse width modulated power source

Claim 2

A pulse width modulated power source to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply term-inal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to produce a waveform between two of the A, B and C load terminals having an initial, middle and a final voltage pulse in each half cycle thereof, and said initial and final voltage pulses being separated by a 120* duration with said middle voltage pulse occupying a portion of said 120* duration.

Claim 3

A pulse width modulated power source as set forth in claim 1, wherein said initial voltage pulse is substantially equal in time duration to said final voltage pulse.

Claim 4

A pulse width modulated power source as set forth in claim 1, wherein said switch means includes solid state switch means.

Claim 5

A pulse width modulated power source as set forth in claim 1, wherein the power source is a three phase variable frequency inverter.

Claim 6

A pulse width modulated source as set forth in claim 1, wherein said control means actuates said switch means to produce a waveform between each two of the load terminals having said initial, middle and final voltage pulse in each half cycle thereof.

Claim 7

A pulse width modulated power source as set forth in claim 1, wherein said waveform is produced by interacting a reference voltage waveshape and a triangular voltage waveshape.

Claim 8

A pulse width modulated power source as set forth in claim 6, wherein said reference voltage waveshape and said triangular voltage waveshape are variable relative to each other to produce a variable fundamental component of said waveform.

Claim 9

A pulse width modulated source as set forth in claim 6, wherein said reference voltage has a constant amplitude at least for 180* of the fundamental of the voltage between two of the load terminals.

Claim 10

A three phase pulse width modulated power source to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to produce a waveform between two of the load terminals having an initial, middle and a final voltage pulse in each half cycle thereof, and said voltage pulses being variable in disposition throughout each half cycle within a range of variation with the sum of the time durations of said voltage pulses being substantially equal to 120*.

Claim 11

A three phase pulse width modulated power source to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to produce a waveform between two of the load terminals having an initial, middle and a final voltage pulse in each half cycle thereof, and said voltage pulses being variable in disposition throughout each half cycle within a range of variation with the sum of the time durations of said voltage pulses being substantially equal to 120*.

Claim 12

A pulse width modulated power source as set forth in claim 9, wherein said range of variation of each of said initial and final voltage pulses is approximately 30*.

Claim 13

A pulse width modulated power source having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to apply a voltage from said power supply between two of the load terminals in a substantially symmetrical waveform having an initial, middle and final pulse in each half cycle of said waveform, and said pulses being variable within a range of variation to produce a variable fundamental component with a substantially constant root mean square value for said waveform.

Claim 14

A pulse width modulated power source having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to apply a voltage from said power supply between two of the load terminals in a substantially symmetrical waveform having an initial, middle and final pulse in each half cycle of said waveform, and said pulses being variable within a range of variation to produce a variable fundamental component with a substantially constant root mean square value for said waveform.

Claim 15

A pulse width modulated power source having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to apply potential from said power supply to each of the A, B and C load terminals in a substantially symmetrical waveshape having an initial, middle and final portion in each half cycle thereof, and said initial and final portions being different in potential from said middle portion in each half cycle and being variable within a range of variation to produce a voltage waveform between two of said load terminals having a variable fundamental component and a substantially constant root mean square value for said waveform.

Claim 16

A pulse width modulated power source having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a power supply having a first and a second supply terminal, a plurality of switch means, said switch means connecting the A, B and C load terminals to said first and second supply terminals, control means actuating said switch means to apply potential from said power supply to each of the A, B and C load terminals in a substantially symmetrical waveshape having an initial, middle and final portion in each half cycle thereof, and said initial and final portions being different in potential from said middle portion in each half cycle and being variable within a range of variation to produce a voltage waveform between two of said load terminals having a variable fundamental component and a substantially constant root mean square value for said waveform.

Claim 17

A pulse width modulated power source having phases A, B and C to power a load having load terminals A, B and C, comprising in combination, a power supply having a positive and a negative supply terminal relative to each other, a plurality of switch means, said switch means connecting the A, B and C load terminals to said positive and negative supply terminals, control means actuating said switch means to apply positive and negative potentials from said power supply between two of the A, B and C load terminals in a waveform having an initial, middle and a final voltage pulse in each half cycle thereof, and said middle voltage pulse symmetrically occupying a middle section of a 120* duration with the end sections of said 120* duration displaced without said 120* duration to form said initial and final voltage pulses.

Claim 18

A pulse width modulated power source having phases A, B and C to power a load having load terminals A, B and C, comprising in combination, a power supply having a positive and a negative supply terminal relative to each other, a plurality of switch means, said switch means connecting the A, B and C load terminals to said positive and negative supply terminals, control means actuating said switch means to apply positive and negative potentials from said power supply between two of the A, B and C load terminals in a waveform having an initial, middle and a final voltage pulse in each half cycle thereof, and said middle voltage pulse symmetrically occupying a middle section of a 120* duration with the end sections of said 120* duration displaced without said 120* duration to form said initial and final voltage pulses.

Claim 19

A pulse width modulated power source as set forth in claim 13, wherein said initial and final voltage pulses are adjacent to 30* and 150* points, respectively, relative to half cycle points of the fundamental component of said waveform.

Claim 20

A three phase pulse width modulated inverter having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a DC power source having a first and a second supply terminal, first through sixth switch means, said first and second switch means connected in series between said supply terminals, said third and fourth switch means connected in series between said supply terminals, said fifth and sixth switch means connected in series between said supply terminals, means connecting said first and second switch means to load terminal A, means connecting said third and fourth switch means to load terminal B, means connecting said fifth and sixth switch means to load terminal C, control means actuating said switch means to apply a waveform of voltage between two of the A, B and C load terminals having an initial, middle and final voltage pulse in each half cycle thereof, said initial and final voltage pulses being separated by a 120* duration with said middle voltage pulse symmetrically occupying a middle section of said 120* duration, and said voltage pulses being variable within a range of variation with said initial and final voltage pulses being displaced from and equal to the unoccupied end sections of said 120* duration.

Claim 21

A three phase pulse width modulated inverter having phases A, B and C to power a load having A, B and C load terminals, comprising in combination, a DC power source having a first and a second supply terminal, first through sixth switch means, said first and second switch means connected in series between said supply terminals, said third and fourth switch means connected in series between said supply terminals, said fifth and sixth switch means connected in series between said supply terminals, means connecting said first and second switch means to load terminal A, means connecting said third and fourth switch means to load terminal B, means connecting said fifth and sixth switch means to load terminal C, control means actuating said switch means to apply a waveform of voltage between two of the A, B and C load terminals having an initial, middle and final voltage pulse in each half cycle thereof, said initial and final voltage pulses being separated by a 120* duration with said middle voltage pulse symmetrically occupying a middle section of said 120* duration, and said voltage pulses being variable within a range of variation with said initial and final voltage pulses being displaced from and equal to the unoccupied end sections of said 120* duration.

Claim 22

A pulse width modulated power source having phases A, B and C to power a load having windings A, B and C and load terminals therefor, comprising, in combination, a power supply having a positive and a negative supply terminal relative to each other, a plurality of switch means, said switch means connecting the A, B and C load terminals to said positive and negative supply terminals, control means actuating said switch means to apply positive and negative potentials from said power supply to eAch of the A, B and C load terminals in a waveshape having an initial, middle and final portion in each half cycle of the waveshape, said initial and final portions being different in polarity from said middle portion in each half cycle of said waveshape, and said middle portion having a polarity identical to the polarity of the fundamental component of the respective load winding waveform.

Claim 23

A pulse width modulated power source having phases A, B and C to power a load having windings A, B and C and load terminals therefor, comprising, in combination, a power supply having a positive and a negative supply terminal relative to each other, a plurality of switch means, said switch means connecting the A, B and C load terminals to said positive and negative supply terminals, control means actuating said switch means to apply positive and negative potentials from said power supply to eAch of the A, B and C load terminals in a waveshape having an initial, middle and final portion in each half cycle of the waveshape, said initial and final portions being different in polarity from said middle portion in each half cycle of said waveshape, and said middle portion having a polarity identical to the polarity of the fundamental component of the respective load winding waveform.

Claim 24

A pulse width modulated power source as set forth in claim 16, wherein said initial and final portions are variable within a range of variation to produce a voltage waveform between two of said load terminals having a variable fundamental component and a substantially constant root mean square value.

Claim 25

A pulse width modulated power source as set forth in claim 16, wherein said middle portion has a greater duration than said initial and final portion in each half cycle of said waveshape.

Claim 26

A three phase pulse width modulated inverter having a variable fundamental voltage to power a load having load terminals, A, B and C, comprising, in combination, a DC power supply having a positive and a negative terminal relative to each other, pairs of switch means, means connecting said pairs of switch means to said positive and negative terminals from each of the load terminals, control means actuating said switch means to produce polarity reversals at each of the load terminals at substantially 120* phase angles relative to each other, said control means producing half cycle reversals at each half cycle of the respective fundamental component, and said control means establishing a prehalf cycle and a posthalf cycle polarity reversal which are variable in duration before and after said half cycle reversals to produce a waveform between two of said load terminals having an output which has a duration greater than 120*.

Claim 27

A three phase pulse width modulated inverter having a variable fundamental voltage to power a load having load terminals, A, B and C, comprising, in combination, a DC power supply having a positive and a negative terminal relative to each other, pairs of switch means, means connecting said pairs of switch means to said positive and negative terminals from each of the load terminals, control means actuating said switch means to produce polarity reversals at each of the load terminals at substantially 120* phase angles relative to each other, said control means producing half cycle reversals at each half cycle of the respective fundamental component, and said control means establishing a prehalf cycle and a posthalf cycle polarity reversal which are variable in duration before and after said half cycle reversals to produce a waveform between two of said load terminals having an output which has a duration greater than 120*.

Claim 28

A three phase pulse width modulated inverter as set forth in claim 19, wherein the duration between said half cycle reversal and said prehalf cycle reversal is substantially equal to the duration between said half cycle reversal and said posthalf cycle reversal.

Claim 29

A three phase pulse width modulated inverter as set forth in claim 19, wherein the duration between said prehalf cycle reversal and said posthalf cycle reversal is less than 60*.

Claim 30

A three phase pulse width modulated inverter as set forth in claim 19, wherein the duration between said prehalf cycle reversal and said posthalf cycle reversal is variable to vary the fundamental component of said waveform.