SU1672484A1 - Device for modelling autonomous 3-phase voltage invertor - Google Patents

Abstract

The invention relates to the simulation of electrical systems and can be used in the study on analog computers of alternating current transmission, which contain autonomous voltage inverters and asynchronous motors in the loop of the automatic control system. The purpose of the invention is to enhance the functionality by providing power transmission modeling in driving and braking modes. The device contains a power source, four phase current drivers, three matching blocks, a load model, and three phase models, each of which includes two controlled keys and two elements with one-sided conductivity. 5 il.

Description

The image relates to the field of modeling electrical systems and can be used in the study on analog computers of alternating-go power transmission, containing autonomous voltage inverters (AIN) and asynchronous motors (BP) in the loop of the automatic control system (ACS).

The purpose of the invention is the extension of functionality by simulating power transmission in driving and braking modes.

Fig. 1 is a diagram of a device for simulating a three-phase self-contained voltage inverter; in fig. 2 is a control key diagram; FIG. 3 is a diagram of a phase current driver; FIG. 4 is a diagram of a matching unit in FIG. 5 is a device replacement circuit.

A device for simulating a three-phase autonomous voltage inverter consists of the first 1. second 2 and third 3 phase models, each of which includes the first 4 and second 5 controlled keys, as well as the first 6 and second 7 elements with one-way conductivity, the first 8, second 9, third 10 and fourth 11 phase formers, first 12, second 13 and third 14 th units, load model 15 and power supply 16, clock generator 17

The keys 4 and 5 are identical in the scheme, which consists of transistors 18 and 19, operating in the key mode opt

io

xl N .N 00

N

Ron pairs 20 and 2 1 and diode 22, resistors 23-25.

The first 8, the second 9. the third 10 and the fourth 11 phase current drivers are made according to the scheme of the current source on the operational amplifiers 26 and 27. The adder 28 (Fig. 3). They serve to form and measure the currents of the phases of the AIN model.

Resistor 29 is turned on in the input circuit of amplifier 26, and resistors 30 and 31 are connected in the return circuit. Each matching unit (Fig. 4) contains amplifiers 32 and 33, resistor 34, and adder 35.

FIG. 5 shows a device replacement circuit including elements 36-41 with one-sided conductivity, controlled keys 42-47, stator windings 48-50 phases A, B, C of an induction motor.

The optocoupler pairs of the first 4 and second 5 controlled keys provide galvanic isolation of the power circuit and the control circuit, thereby increasing the reliability of the device, and the use of electronic control keys - speed, ensuring, in real time,

The device works as follows.

Controlled keys 4 and 5 of each phase model simulate the operation of a three-phase thyristor bridge with the following assumptions:

the thyristor key is represented by an inertia-free element;

losses in the thyristor switch are taken into account by choosing the type of transistor and the corresponding scales of the variables (voltage, current).

At the same time, three controllable keys (one in each phase model) can be in a conducting state. When a control potential is applied from the generator 17 to the base of the transistor 18. The action time of which is determined by the required duration of a certain block of controlled keys being in the conducting state (6,180 °, 120 °, 0,150 °), the current flowing through the optocoupler - a pair of 20. leads to an emf in it, which provides unlocking of the key element assembled on the transistor 19, thereby ensuring the flow of current from the positive bus of the power supply unit 16 through the phase current drivers, controlled keys and diode cells located in a conductive state, matching units and the load model to the negative bus of the power supply unit.

When locking, for example, the second controlled key 5, a reactive current will flow through the second element 7 with one-sided conductivity. As a result of this to

the junction of the collector base of the transistor 19 will be applied to the forward bias voltage, which will cause the flow of spurious current in this circuit. To eliminate this phenomenon in the cathode circuit of the transistor 19

diode 22 is installed.

Thus, the controllable keys pass the active component of the load current in the traction mode, and in the braking mode the magnetizing component

phase current of an asynchronous machine operating a generator.

The active component of the phase current ia used in the CAP transmission, according to the instantaneous replacement schemes work

AIN is defined as the sum of the currents.

ia ia ik4.

where iaT is current. flowing in the bus connected to the first input of the phase model:

ikq is the current flowing in the power rail. connected to the fourth input of the phase model.

The total in-phase current is defined as

in iaT iaq.

where iaq is the current flowing in the bus connected to the second input of the phase model.

Reactive current ip is defined as follows.

ip - iaq.

From the outputs of operational amplifiers 27

the corresponding current conditioners are relieved of the voltage Uq laT. proportional to the currents ikq and a, summing up with the help of the operational amplifier 28, we obtain a voltage proportional to the active component of the load current a, which can later be used in the automatic control system of the power transmission system. Coordination of phase currents d, IB, ic models of phases AIN with phase currents of the model

loads 15 are carried out using matching blocks 12 14. which provide communication between the physical and mathematical parts of the model, which are designed as current source converters that are tracking systems that, with a constant voltage on the voltage and a varying voltage on the low frequency ( constant voltage drop across a resistor 34 connected in series to the load circuit, a separate converter being used to match the currents of each phase

When current flows through matching blocks, voltages are generated at the outputs of the operating amplifiers 33, of which with the help of adder 35 phase voltage is used, which is used in the simulation of arterial pressure as a function of disturbance.

When a back-EMF (generating mode of the BP operation) appears in the phases of the AD, the current flows through the elements with one-sided conductivity, thus ensuring the operation of the transmission in the braking mode.

Since the configuration of the AIN model and the real AIN are identical, and the energy is exchanged between the power source, the inverter and the AD as similarly (which is provided by simulating the AHN based on physical analogs), it is possible to carry out power transmission studies braking.

Claims (1)

Invention Formula A device for simulating a three-phase self-contained inverter voltage, containing a power source, a first phase model, including first and second controlled keys, first and second elements with one-sided conductivity, and a load model, which functionality by providing power modeling in the second and third phase models, three matching blocks, the first and second phase tokens, the information inputs of which are connected and connected to the positive power supply bus, the third and fourth phase currents tokens, the information inputs of which are connected and connected to the negative power supply bus, the output of the first phase current driver is connected to the information inputs of the first controlled by all the phase models, respectively, the output of the second phase current driver They are connected to the current inputs of the first elements with one-sided conductance of all phase models, respectively, the output of the third phase current generator is connected to the information inputs of the second controlled switches of all phase models, respectively, the control inputs of controlled switches of all phase models are connected to the corresponding outputs of the clock generator, the output the fourth phase current driver is connected to the current inputs of the second elements with one-sided conductivity of all phase models, respectively, you first and orogo actuated keys and of first and second single-sided conductive pattern in each phase are connected between the oboe and through corresponding matching blocks are connected to data inputs of the load model -and 24 77 one F «y4 HYP 2G 4H4-IN4 I s s 25 -O . .З g 55 w t at 50 Y FIG. five