Apparatus for providing the pilot values of characteristics of an asynchronous three phase machine

Claim 2

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from its primary current and voltage, said apparatus comprising current transformer means connected in at least t9o leads of said machine, said current transformer means comprising a pair of current transformers each having a primary winding connected in a corresponding one of the leads of said machine and a secondary winding, an ohmic resistance and an inductive reactance connected in series circuit arrangement across each of said secondary windings for providing voltages proportional to the phase current and its differential quotient, integrator means, and coupling means for applying said voltages and the subordinated phase voltage to said integrator means to provide at said integrator means signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*; multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by the signals provided at said integrator means, said multiplying means multiplying each signal magnitude by itself as well as by the other; and summing means connected to the output means of said multiplying means.

Claim 3

Apparatus as claimed in claim 1, wherein said multiplying means comprises a pair of multipliers each having a first input and a second input, first input means connected to the first inputs of said multipliers for supplying a first signal having a magnitude proportional to one of said flux components, and second input means connected to the second inputs of said multipliers for supplying a second signal having a magnitude proportional to the sum of the magnitude of said first signal and a magnitude proportional to the other of said flux components.

Claim 4

Apparatus as claimed in claim 1, wherein said multiplying means comprises a pair of parabolic multipliers each having a first input and a second input, input means connected to the first and second inputs of one of said multipliers for supplying a signal having a magnitude proportional to one of said flux components, and input means connected to the first and second inputs of the other of said multipliers for supplying a signal having a magnitude proportional to the other of said flux components.

Claim 5

Apparatus as claimed in claim 1, further comprising a square root extracting function generator having an input, and wherein said summing means has an output connected to the input of said function generator.

Claim 6

Apparatus as claimed in claim 3, wherein each of said multipliers comprises a square function generator having a plurality of biased threshold diodes.

Claim 7

Apparatus as claimed in claim 1, further comprising a pair of proportion amplifiers, and wherein said integrator means comprises a pair of integrators each coupled to the secondary winding of a corresponding one of said current transformers, each of said proportion amplifiers being connected across a corresponding one of said integrators in feedback relation for suppressing direct current.

Claim 8

Apparatus as claimed in claim 6, wherein the quotient of the double integral time of said integrators and the integral time of said proportion amplifiers are equal to or less than the proportional amplification thereof.

Claim 9

Apparatus as claimed in claim 7, wherein the proportional amplification is as small as possible.

Claim 10

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage of converter means utilized to measure the machine, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first input and a second input and an output providing a signal having a magnitude proportional to the instantaneous torque of said machine, input means connected to the first inputs of said multipliers for supplying to said first inputs a magnitude proportional to the instantaneous value of the secondary flux or the main flux of one phase, input means connected to the second inputs of said multipliers for supplying to said second inputs a magnitude proportional to the primary current of the other phase and a summary device connected to the outputs of said multipliers for providing the difference between the output signals of said multipliers; and summing means connected to the output means of said multiplying means.

Claim 11

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage of converter means utilized to measure the machine, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first input and a second input and an output providing a signal having a magnitude proportional to the instantaneous torque of said machine, input means connected to the first inputs of said multipliers for supplying to said first inputs a magnitude proportional to the instantaneous value of the secondary flux or the main flux of one phase, input means connected to the second inputs of said multipliers for supplying to said second inputs a magnitude proportional to the primary current of the other phase and a summary device connected to the outputs of said multipliers for providing the difference between the output signals of said multipliers; and summing means connected to the output means of said multiplying means.

Claim 12

Apparatus as claimed in claim 9, further comprising divider means having first and seconD inputs and an output for providing a magnitude proportional to the slip frequency of said machine, the first input of said divider means being connected to said summing device for providing a dividend to said divider means, and additional input means connected to the second input of said divider means for supplying to said divider means a divisor having a magnitude proportional to the sum of the squares of the secondary rotary flux of said machine.

Claim 13

Apparatus as claimed in claim 10, further comprising an additional multiplier having first and second inputs and an output for producing a magnitude proportional to the torque of said machine, the output of said divider means being connected to the first input of said additional multiplier, and further input means connected to the second input of said additional multiplier for supplying to said additional multiplier a signal having a magnitude proportional to the sum of the squares of the main rotary flux of said machine.

Claim 14

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first input and a second input and an output for producing a signal having a magnitude proportional to the instantaneous torque of said machine, a summing device connected to the outputs of said multipliers for providing the difference of said outputs, input means connected to the first inputs of said multipliers for supplying to said first inputs the difference between instantaneous magnitudes of the secondary flux of said machine and magnitudes proportional to the primary currents of two phases and input means connected to the second inputs of said multipliers for supplying to said second inputs the sum of said primary current proportional magnitudes minus twice a magnitude proportional to the secondary flux or primary current of the third phase of said machine; and summing means connected to the output means of said multiplying means.

Claim 15

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first input and a second input and an output for producing a signal having a magnitude proportional to the instantaneous torque of said machine, a summing device connected to the outputs of said multipliers for providing the difference of said outputs, input means connected to the first inputs of said multipliers for supplying to said first inputs the difference between instantaneous magnitudes of the secondary flux of said machine and magnitudes proportional to the primary currents of two phases and input means connected to the second inputs of said multipliers for supplying to said second inputs the sum of said primary current proportional magnitudes minus twice a magnitude proportional to the secondary flux or primary current of the third phase of said machine; and summing means connected to the output means of said multiplying means.

Claim 16

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage of converter means utilized to measure the machine, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first pair of inputs and a second pair of inputs and an output for providing a signal having a magnitude proportional to the instantaneous rotary speed of said machine, input means connected to the first pair of inputs of said multipliers for supplying to said first pair of inputs a magnitude proportional to the instantaneous magnitude of the secondary flux of one phase of said machine, input means connected to the second pair of inputs of said multipliers for supplying to said second pair of inputs a magnitude proportional to the derivatives of the other phases of said machine relative to time, a first operation amplifier, a second operation amplifier, a summing device connected to the output of one of said multipliers via the first amplifier and connected to the output of the other of said multipliers via the second amplifier in a manner whereby the outputs of said multipliers are subtractively supplied to said summing device and a magnitude proportional to the torque of said machine is supplied to said summing device, a divider having first and second inputs and an output, the output of said summing device being directly connected to the first input of said divider for supplying the dividend to said divider, and additional input means connected to the second input of said divider for supplying to said divider a divisor having a magnitude proportional to the sum of the squares of the secondary rotary flux of said machine; and summing means connected to the output means of said multiplying means.

Claim 17

Apparatus for providing the pilot values of characteristics of an asynchronous three-phase machine from the primary current and voltage of converter means utilized to measure the machine, said apparatus comprising multiplying means having output means for producing a signal having a magnitude proportional to the sum of the squares of the rotary flux vectors and the induced three-phase voltage vector by first producing signals having instantaneous magnitudes proportional to flux components of voltages induced in two winding axes spaced from each other by 120*, said multiplying means multiplying each signal magnitude by itself as well as by the other, said multiplying means comprising a pair of multipliers each having a first pair of inputs and a second pair of inputs and an output for providing a signal having a magnitude proportional to the instantaneous rotary speed of said machine, input means connected to the first pair of inputs of said multipliers for supplying to said first pair of inputs a magnitude proportional to the instantaneous magnitude of the secondary flux of one phase of said machine, input means connected to the second pair of inputs of said multipliers for supplying to said second pair of inputs a magnitude proportional to the derivatives of the other phases of said machine relative to time, a first operation amplifier, a second operation amplifier, a summing device connected to the output of one of said multipliers via the first amplifier and connected to the output of the other of said multipliers via the second amplifier in a manner whereby the outputs of said multipliers are subtractively supplied to said summing device and a magnitude proportional to the torque of said machine is supplied to said summing device, a divider having first and second inputs and an output, the output of said summing device being directly connected to the first input of said divider for supplying the dividend to said divider, and additional input means connected to the second input of said divider for supplying to said divider a divisor having a magnitude proportional to the sum of the squares of the secondary rotary flux of said machine; and summing means connected to the output means of said multiplying means.