Inverting arrangement employing compressed sine waves and class B amplifiers

Claim 2

An electrical amplifying arrangement for amplifying a three phase alternating current signal, each phase voltage of the signal having a substantially sinusoidal waveshape with the peaks thereof flattened and consisting primarily of the fundamental and the third harmonic, comprising: a class B amplifier for each phase of the three phase signal; a three phase transformer having a three leg core to provide a third harmonic shunt; an inductor in series with the primary winding of each phase of said transformer; and a capacitor transformer coupled to all of said inductors to form parallel resonant bandstop filler elements.

Claim 3

An inverting arrangement for converting a source of direct current supply potential into an alternating current source comprising: generating means to convert the supply potential into a three phase alternating current signal, each phase voltage of said signal having a substantially sinusoidal waveshape with the peaks thereof flattened and consisting primarily of the fundamental and the third harmonic; a first class B amplifier for each phase of said three phase alternating current signal, each of said first amplifiers having the supply potential applied thereto; a second class B amplifier associated with each of said first amplifiers, the output of each of said second amplifiers being connected to the output of the associated first amplifier, and each of said second amplifiers having less than the entire magnitude oF the supply potential applied thereto, a three phase transformer having a three leg core connected to receive the outputs of said amplifiers to provide a third harmonic shunt therefor, an inductor in series with the primary winding of each phase of said transformer, a capacitance in parallel with each of said inductors to form parallel resonant third harmonic bandstop filter elements; and control means causing said first amplifiers to carry load current only when the associated second amplifiers are saturated.

Claim 4

An inverting arrangement for converting a source of direct current supply potential into an alternating current source comprising: generating means to convert the supply potential into a three phase alternating current signal, each phase voltage of said signal having a substantially sinusoidal waveshape with the peaks thereof flattened and consisting primarily of the fundamental and the third harmonic; a first class B amplifier for each phase of said three phase alternating current signal, each of said first amplifiers having the supply potential applied thereto; a second class B amplifier associated with each of said first amplifiers, the output of each of said second amplifiers being connected to the output of the associated first amplifier, and each of said second amplifiers having less than the entire magnitude oF the supply potential applied thereto, a three phase transformer having a three leg core connected to receive the outputs of said amplifiers to provide a third harmonic shunt therefor, an inductor in series with the primary winding of each phase of said transformer, a capacitance in parallel with each of said inductors to form parallel resonant third harmonic bandstop filter elements; and control means causing said first amplifiers to carry load current only when the associated second amplifiers are saturated.

Claim 5

An inverting arrangement as claimed in claim 2 wherein said capacitance comprises a single capacitor transformer coupled to each of said inductors.

Claim 6

An inverting arrangement as claimed in claim 2 and further comprising a third class B amplifier associated with each of said first amplifiers, the output of each of said third amplifiers being connected to the output of the associated first amplifier, each of said third amplifiers having less than the entire magnitude of the supply potential, but a higher magnitude thereof than that applied to said second amplifier, applied thereto, and said control means causing said third amplifiers to carry load current only when the associated second amplifiers are saturated and said first amplifiers to carry load current only when the associated third amplifiers are saturated; wherein each of said third amplifiers has one half the magnitude of the supply potential applied thereto; each of said second amplifiers has the reference side of the supply potential applied thereto; said first amplifiers each comprise first and second transistors connected for push-pull operation; said second amplifiers each comprise third and fourth transistors connected for push-pull operation; and said third amplifiers each comprise fifth and sixth transistors connected for push-pull operations; and wherein: the primary winding of each phase of said transformer is center-tapped to form first and second sections, the center tap being connected to the reference side of the supply potential; the emitters of said first, third and fifth transistors are connected to the other end of said first section of a related primary winding of said transformer; the emitters of said second, fourth and sixth transistors are connected to the other end of said second section of a related primary winding of said transformer; and said first and second sections of the primary windings of said transformer are center-tapped and the center tap is connected to the collectors of the related fifth and sixth transistors to provide the necessary voltage having a potential one half the magnitude of the supply potential.

Claim 7

An inverting arrangement as claimed in claim 4 and further comprising: a first inductor connected between the emitters of said first, third and fifth transistors and the end of said first section of the related primary winding of said transformer for each phase; a second inductor connected between the emitters of said second, fourth and sixth transistors and the end of said second section of the related primary winding of said transformer for each phase; and a capacitor transformer coupled to all of said first and second inductors to form parallel resonant third harmonic bandstop filter elements.

Claim 8

An inverting arrangement as claimed in claim 5 wherein for each phase said control means comprises; a first switching device connected to the base of said first transistor; a second switching device connected to the base of said second transistor; a third switching device connected to the base of said fifth transistor; a fourth switching device connected to the base of said sixth transistor, said switching devices adapted to block said alternating current signal from being applied to the bases of said transistors unless actuated to pass said signal; first switch actuating means to actuate said first switching device to pass said signal only when said fifth traNsistor is saturated; second switch actuating means to actuate said second switching device to pass said signal only when said sixth transistor is actuated; third switch actuating means to actuate said third switching device to pass said signal only when said third transistor is saturated; and fourth switch actuating means to said fourth switching device to pass said signal only when said fourth transistor is saturated.

Claim 9

An electrical amplifying arrangement for amplifying a three phase alternating current signal, each phase voltage of the signal having a waveshape substantially sinusoidal with the peaks thereof flattened, comprising: a first class B amplifier for each phase of the three phase alternating current signal, each of said first amplifiers having a first supply voltage of a given magnitude applied thereto; a second class B amplifier associated with each of said first amplifiers, the output of each of said second amplifiers being connected to the output of the associated first amplifier, and each of said second amplifiers having a second supply voltage applied thereto that has a magnitude less than the magnitude of said first supply voltage; a third class B amplifier associated with each of first amplifiers, the output of each of said third amplifiers being connected to the output of the associted first amplifier, each of said third amplifiers having a third supply voltage applied thereto that has a magnitude less than the magnitude of said first supply voltage and greater than the magnitude of said second supply voltage; and control means causing said first amplifiers to carry load current only when the associated second amplifiers are saturated, and causing said third amplifiers to carry load current only when the associated second amplifiers are saturated and causing said first amplifiers to carry load current only when said third amplifiers are saturated; wherein said third suppply voltage is one half the magnitude of said first supply voltage; and said second supply voltage is the reference for said first and second supply voltages; wherein said first amplifiers each comprise first and second transistors connected for push-pull operation; said second amplifiers each comprise third and fourth transistors connected for push-pull operation; and said third amplifiers each comprise fifth and sixth transistors connected for push-pull operation, said first, third and fifth transistors being active for one half cycle of the output current, while said second, fourth and sixth transistors are active for the other half cycle of the output current; wherein said control means comprises: first switching means associated with each of said first transistors; second switching means associated with each of said second transistors; third switching means associated with each of said fifth transistors; fourth switching means associated with each of said sixth transistors, said switching means adapted to block or pass the alternating current signal; and switch actuating means causing said first switching means to pass the signal only when said fifth transistor is saturated, said third switching means to pass the signal only when said third transistor is saturated, said second switching means to pass the signal only when said sixth transistor is saturated, and said fourth switching means to pass the signal only when said fourth transistor is saturated; wherein: each of said switching means is a switching transistor; and said switch actuating means comprises a switch actuating transistor associated with each of said switching transistors, each of said switch actuating transistors connected to shunt the signal from the base of the associated switching transistor except when that switching transistor is to pass the signal; wherein: the alternating current signal consists primarily of the fundamental and the third harmonic; and the amplifying arrangement further comprises fIlter means to remove the third harmonic from the signal at the output of said amplifiers; wherein: said filter means comprises a three phase transformer having a three leg core to provide a third harmonic shunt; and wherein said filter means further comprises: an inductor in series with the primary winding of each phase of said transformer; and a capacitor transformer coupled to all of said inductors to form parallel resonant third harmonic bandstop filter elements.

Claim 10

An electrical amplifying arrangement for amplifying a three phase alternating current signal, each phase voltage of the signal having a waveshape substantially sinusoidal with the peaks thereof flattened, comprising: a first class B amplifier for each phase of the three phase alternating current signal, each of said first amplifiers having a first supply voltage of a given magnitude applied thereto; a second class B amplifier associated with each of said first amplifiers, the output of each of said second amplifiers being connected to the output of the associated first amplifier, and each of said second amplifiers having a second supply voltage applied thereto that has a magnitude less than the magnitude of said first supply voltage; a third class B amplifier associated with each of first amplifiers, the output of each of said third amplifiers being connected to the output of the associted first amplifier, each of said third amplifiers having a third supply voltage applied thereto that has a magnitude less than the magnitude of said first supply voltage and greater than the magnitude of said second supply voltage; and control means causing said first amplifiers to carry load current only when the associated second amplifiers are saturated, and causing said third amplifiers to carry load current only when the associated second amplifiers are saturated and causing said first amplifiers to carry load current only when said third amplifiers are saturated; wherein said third suppply voltage is one half the magnitude of said first supply voltage; and said second supply voltage is the reference for said first and second supply voltages; wherein said first amplifiers each comprise first and second transistors connected for push-pull operation; said second amplifiers each comprise third and fourth transistors connected for push-pull operation; and said third amplifiers each comprise fifth and sixth transistors connected for push-pull operation, said first, third and fifth transistors being active for one half cycle of the output current, while said second, fourth and sixth transistors are active for the other half cycle of the output current; wherein said control means comprises: first switching means associated with each of said first transistors; second switching means associated with each of said second transistors; third switching means associated with each of said fifth transistors; fourth switching means associated with each of said sixth transistors, said switching means adapted to block or pass the alternating current signal; and switch actuating means causing said first switching means to pass the signal only when said fifth transistor is saturated, said third switching means to pass the signal only when said third transistor is saturated, said second switching means to pass the signal only when said sixth transistor is saturated, and said fourth switching means to pass the signal only when said fourth transistor is saturated; wherein: each of said switching means is a switching transistor; and said switch actuating means comprises a switch actuating transistor associated with each of said switching transistors, each of said switch actuating transistors connected to shunt the signal from the base of the associated switching transistor except when that switching transistor is to pass the signal; wherein: the alternating current signal consists primarily of the fundamental and the third harmonic; and the amplifying arrangement further comprises fIlter means to remove the third harmonic from the signal at the output of said amplifiers; wherein: said filter means comprises a three phase transformer having a three leg core to provide a third harmonic shunt; and wherein said filter means further comprises: an inductor in series with the primary winding of each phase of said transformer; and a capacitor transformer coupled to all of said inductors to form parallel resonant third harmonic bandstop filter elements.

Claim 11

An electrical amplifying arrangement as claimed in claim 33 wherein said three phase transformer comprises: a primary winding for each phase; a center tap for each of said primary windings to divide each of said primary windings into two sections for push-pull operation; and center taps for each of said sections of each of said primary windings to provide said third supply voltages for said fifth and sixth transistors.