SU817496A1 - Device for determining induction motor torque - Google Patents

Description

The invention relates to electric vehicles and can be used to determine electromagnetic moments in the control and monitoring systems of electric drives with asynchronous electric motors with a phase rotor. A device for determining the electromagnetic moment of an electric machine is known, which contains an EMF sensor in the form of a measuring winding in the stator winding zone, two power galvanometers, the loops of which are connected to the EMF sensor, one directly and the second through an integrating circuit, and the electromagnet windings. These galvanometers are connected successively with the stator winding of the motor body. One directly, and the other through a differentiating chain, and parallel to the winding of the electromagnet of the galvanometer with a loop connected to the integrating circuit and the differential circuit, the resistor 1 is turned on. The disadvantage of this known device is the low measurement accuracy and design complexity. The closest to the technical essence and the achieved result of the present invention is a device for determining the torque of an asynchronous electric motor, containing three sensors of phase voltages, three sensors of phase currents of the stator winding connected to the sensors of phase voltages of the component of determining voltages two rectangular coordinates, connected to three sensors of phase currents of the stator winding, the determination unit was to the two currents on two rectangular coordinates connected to the output Two units for determining the components of the derivative of the flux linkage along two rectangular coordinates, two integration units connected to the outputs of these elements, two multiplication units, the first inputs of which are connected to the outputs of two integration units, and the second of them are connected to the outputs of the determination unit the corresponding currents of the stator winding in two rectangular coordinates connected to the outputs of the two multiplication units of the summation element 2. The disadvantage of this known device is the lack of accuracy in determining the moment, and the error can be especially significant with prolonged, for example, in the control system, the disappearance of zero integration blocks.

The purpose of the invention is to increase the accuracy of the moment determination.

Ukazonna - the goal is achieved by the fact that the device containing at least One sensor of the electrical parameters of the stator winding and the multiplication unit is equipped with a square root determination unit of the algebraic sum of squares of input signals. One of the inputs of which is connected to the output of the current sensor stator winding one of the inputs of the multiplication block. In addition, a rotor winding current sensor is introduced into the device, the output of which is connected to the second input of the square root determining unit of the algebraic sum of squares of the input signals and the second input of the multiplication unit, as well as the algebraic square root determining unit. squares of the input signals are connected to the multiplication unit through an algebraic sum element introduced into the device, to another input of which the output of the stator winding current sensor is connected, and to another input of the multiplication unit the output of the current sensor of the stator core is connected directly to A square of the algebraic sum of squares of the input signals is connected to the voltage sensor of the stator winding.

Fig. 1 shows one example of the device; . The second embodiment of the device. 40 The device (FIG. 1) contains a current sensor 1 of the stator winding, multiplication unit 2, a rotor-sensor 3. winding, block 4, determining the square root of the algebraic sum of squares of input signals, made, for example, in the form of an operational amplifier 5, with non-linear parasol characteristics with 6–8 parameters connected to its feedback circuits and inputs, device {fig. 2) contains, instead of the current sensor of the rotor winding, the sensor 9 of the voltage of the stator winding and the element 10 of algebraic summation. . The device according to FIG. 1 follows the following way. To the inputs of block 4 for determining the square root of an algebraic sum, 0 No. I squares of input signals, signals proportional to the current J of the stator winding (from sensor 1) and J X are received. And Vi and Vi, 4.j-I .- x -, -. current Jj potov new winding (p. sensor 3).

In this case, at the output of block 4, a signal is formed that is proportional to the value of

V

 -

y / x v x j /

After moving this signal to the output signal of the sensor 3 of the current J2 of the rotor winding at the output of the multiplication unit 2 (), a signal proportional to the torque of the asynchronous electric motor is formed

3X (uJ

xlj

J7 (1

M

about57

where (l) is the synchronous angular velocity of the electric motor; X 1, X - inductive resistance of the magnetization circuit and reduced to the stator: winding phase inductive resistance of the rotor winding.

The device according to FIG. 2 operates as follows.

The inputs of block 4 calculating the square root of the algebraic sum of squares of input signals receive signals from the outputs of sensor 1 of current J and sensor 9 of voltage - U of the stator winding of an asynchronous electric motor, and the output of this block 4 produces a signal proportional to

Vub to and

After algebraically summing this signal with the output signal of current sensor 1 J at the output of the output element 10, a signal is obtained that is proportional to the value of a xcc 2 but xp Cce bi 2, multiplying the last signal by the output signal of current sensor 1 J, results in proportional to the electromagnetic moment of the asynon electric motor to, J, (V, - - K, jJ,) .. The constant coefficients K, Kj and, determined by the parameters of the input pins of the corresponding elements, are expressed in accordance with dependency 14,) 1-1; ).

Claims (3)

Claim 1. A device for determining the moment of an asynchronous electric motor, comprising at least one sensor of electrical parameters of the stator winding and a multiplication unit, characterized in that, in order to improve accuracy, it is equipped with a unit for determining the root of the square, which of the algebraic sum of the quad - ⁹ types of input signals, one of the inputs of which is connected to the output of the current sensor of the stator winding, and the output is connected to one of the inputs of the variable block: “ENIN. 2. The device pop. 1, characterized in that a rotor winding current sensor is introduced into it, the output of which is connected to the second input of the unit for determining the square root of the algebraic sum of the squares of the input signals and the second input of the multiplication unit. 3. The device pop. 1, the fact that the output of the block for determining the square root of the algebraic sum of squares of the input signals is connected to the multiplication unit through the algebraic summation element introduced into the device, to the other input of which the output of the stator current sensor is connected moreover, the voltage sensor of the stator winding is connected directly to the other input of the multiplication unit, and the voltage sensor stat is connected to the other input of the block for determining the square root of the algebraic sum of squares of the input signals orn winding.