RU193216U1 - Semiconductor device for non-capacitor starting a three-phase asynchronous electric motor from a single-phase mains - Google Patents

Abstract

A semiconductor device for the non-capacitor starting of a three-phase asynchronous electric motor from a single-phase mains supply is designed to start and reverse a three-phase asynchronous electric motor powered from a single-phase mains, the stator windings of which are connected according to the "triangle" scheme. Two reversible semiconductor switches of a semiconductor device, designed to connect to the stator windings of a three-phase asynchronous electric motor, connected in a "triangle" circuit, are made on pairs of semiconductor switches that are n-p-n transistors. In the first pair of semiconductor switches, the collector of the first transistor is combined with the emitter of the second transistor at the first common point and their common input is designed to connect to the phase of the supply network and with the terminals of the first and second stator windings, the emitter of the first transistor is combined with the collector of the second transistor to the second common point. In the second pair of semiconductor switches, the emitter of the third transistor is combined with the collector of the fourth transistor to the first common point and their common output is intended for connection with the terminals of the second and third stator windings, and the collector of the third transistor is combined with the emitter of the fourth transistor to the second common point. The common output of the first and third stator windings is connected to zero the mains supply of the first pair of semiconductor switches, is designed to connect to the terminals of the second and third stator windings and is connected to the common input of the emitter of the third transistor and the collector of the fourth transistor of the second pair of semiconductor switches, in which the common input of the third collector the transistor and emitter of the fourth transistor is designed to connect to the conclusions of the first and third stator windings. Significantly increases the power taken from the motor shaft, due to an increase in the moment developed by the electric motor, with the creation of a uniform rotating stator field by switching on two semiconductor switches parallel to two stator windings.

Description

The proposed utility model relates to semiconductor and can be used to start and reverse a three-phase asynchronous electric motor, powered by a single-phase network, the stator windings of which are connected according to the "triangle" scheme.

A device is known for the non-capacitive start of a three-phase squirrel-cage induction motor from a single-phase network, in which the stator windings are connected according to the "triangle" scheme. The device contains a pair of on-parallel connected dinistors. One common output of the dynistors is designed to connect to the terminals of the stator windings, one of which is connected to the zero of the single-phase network by one output, and the other by the phase of the single-phase network. Another common output of the dynistors is designed to connect to the outputs of the windings, one of which is connected to the zero of the single-phase network, and the other to the phase of the single-phase network (patent RU 2370876, IPC Н02Р 1/42 (2006.01), Н02Р 1/26 (2006.01)).

The disadvantage of this device is the unpredictability of the direction of rotation of the rotor of the electric motor.

The closest to the proposed utility model in terms of technical nature and the achieved result (prototype) is a semiconductor device for the non-capacitor starting of a three-phase asynchronous electric motor from a single-phase network, containing two reversing semiconductor switches designed for connection with the stator windings of a three-phase asynchronous electric motor connected according to the "triangle" scheme. Two reversible semiconductor switches are made on two pairs of semiconductor switches, which are n-p-n transistors. In the first pair of semiconductor switches, the collector of the first transistor is combined with the emitter of the second transistor to the first common point and their common input is used to connect to the phase of the mains, the emitter of the first transistor is combined with the collector of the second transistor to the second common point and their common output is used to connect to the conclusions first and second stator windings. In the second pair of semiconductor switches, the emitter of the third transistor is combined with the collector of the fourth transistor to the first common point and their common output is used to connect to the terminals of the second and third stator windings, the collector of the third transistor is combined with the emitter of the fourth transistor to the second common point and their common output is intended for connections to the mains phase. The common output of the first and third stator windings is connected to zero power supply. Since only six vectors can be obtained thanks to semiconductor switches, the motor speed with this connection remains unchanged (patent RU 2385527, IPC Н02Р 1/26 (2006.01), НОМ 5/257 (2006.01)).

The main disadvantage of this device is the reduced power removed from the motor shaft, due to the reduced torque developed by the electric motor, due to the narrow elliptical rotating field of the stator.

The technical problem, the solution of which is provided by the implementation of the utility model, is to create a semiconductor device for the non-capacitor starting of a three-phase asynchronous electric motor from a single-phase supply network, which allows to increase the power taken from the motor shaft.

The solution to this technical problem is achieved by the fact that in a semiconductor device for non-capacitor starting a three-phase asynchronous electric motor from a single-phase supply network, containing two reversing semiconductor switches, designed to connect to the stator windings of a three-phase asynchronous electric motor connected in a "triangle" circuit, and made on pairs of semiconductor switches being npn transistors, the collector of the first transistor in the first pair of semiconductor switches combined with the emitter of the second transistor to the first common point and their common input is used to connect to the phase of the supply network, the emitter of the first transistor is combined with the collector of the second transistor to the second common point, in the second pair of semiconductor keys the emitter of the third transistor is combined with the collector of the fourth transistor to the first common the point and their common output is intended for connection with the terminals of the second and third stator windings, and the collector of the third transistor is combined with the emitter of the fourth transistor in volts The common point, the common output of the first and third stator windings is connected to zero of the supply network, according to a utility model in the first pair of semiconductor switches, the common input of the collector of the first transistor and emitter of the second transistor is designed to connect to the terminals of the first and second stator windings, and the common input of the emitter of the first the transistor and the collector of the second transistor is designed to connect to the terminals of the second and third stator windings and is connected to a common input of the emitter of the third transistor and the collector of the fourth a transistor of the second pair of semiconductor switches, in which the common input of the collector of the third transistor and the emitter of the fourth transistor is designed to connect to the terminals of the first and third stator windings.

The increase in power removed from the motor shaft is explained by the increase in the moment developed by the electric motor, due to the creation of a uniform rotating stator field by switching on two semiconductor switches parallel to two stator windings.

The proposed utility model is illustrated in the drawing, where in FIG. 1 is a circuit diagram of a semiconductor device of a non-capacitor starting three-phase asynchronous electric motor from a single-phase supply network; in FIG. 2 is a vector diagram of a stator magnetic field with six vectors; in FIG. 3 is a vector diagram of a stator magnetic field with eight vectors; in FIG. 4 is a clock diagram for constructing six stator magnetic field vectors; in FIG. 5 is a clock diagram for constructing eight stator magnetic field vectors.

In addition, the following notation is used in the drawing:

- VT1, VT2, VT3, VT4 - transistors;

- E - emitter;

- K - collector;

- B - base;

- U ~ - alternating voltage of the supply network;

- Ф - phase of the supply voltage;

- 0 - zero supply voltage;

- A, B, C - stator windings;

- I, II, III, IV, V, VI, VII, VIII - sequential fixed positions of the magnetic flux vector of the circular rotating field of the stator of a three-phase asynchronous electric motor;

- VII (I) - the beginning of a new cycle of clocking of semiconductor switches when creating six vectors;

- IX (I) - the beginning of a new cycle of clocking semiconductor switches when creating eight vectors;

- arcuate lines with arrows - the direction of rotation of the magnetic flux of the stator field;

- straight lines with arrows - magnetic flux directions in the stator windings of a three-phase asynchronous electric motor.

A semiconductor device for the non-capacitor starting of a three-phase asynchronous motor from a single-phase supply network contains two reversible semiconductor switches designed to connect to the stator windings of a three-phase asynchronous electric motor connected in the "triangle" pattern and made on pairs of semiconductor switches, all four of which are n-p-n transistors. In the first pair of semiconductor switches, the collector of the first transistor is combined with the emitter of the second transistor at the first common point and their common input is designed to connect to the phase of the supply network and to connect to the terminals of the first and second stator windings, the emitter of the first transistor is combined with the collector of the second transistor into a second common point, and their common input is designed to connect to the terminals of the second and third stator windings and is connected to the common input of the emitter of the third transistor and the collector of the fourth transistor in a pair of semiconductor switches. In the second pair of semiconductor switches, the emitter of the third transistor is combined with the collector of the fourth transistor to the first common point and their common output is used to connect to the terminals of the second and third stator windings, and the collector of the third transistor is combined with the emitter of the fourth transistor to the second common point, and their common input Designed to connect with the findings of the first and third stator windings. The common output of the first and third stator windings is connected to zero power supply.

Thus, a semiconductor device for non-capacitor starting a three-phase asynchronous motor from a single-phase supply network contains a pair of semiconductor switches made on npn of the first transistor 1 (VT1) and nrn second transistor 2 (VT2), and a pair of semiconductor switches made on n- pn of the third transistor 3 (VT3) and npn of the fourth transistor 4 (VT4), connected counterclockwise - two transistors in parallel, in each of the two reversing semiconductor switches designed to connect to the first stator winding 5 (A), the second stator winding 6 (B) and the third stator winding 7 (C) of the three-phase induction motor, connected in a "triangle". The common output of the first stator winding 5 (A) and the third stator winding 7 (C) is connected to zero 8 (0) of the supply network. So the beginning of the stator winding 5 (A) is connected to zero 8 (0) of the supply voltage, the end of the stator winding 5 (A) is connected to phase 9 (F) of the supply network.

In the first reversible semiconductor switch, the collector of the first transistor 1 (VT1) is connected to the emitter of the second transistor 2 (VT2), forming the first common point 10, and their common input is designed to connect to the supply network phase 9 (Ф) and to the terminals of the first stator winding 5 (A) and a second stator winding 6 (B); the emitter of the first transistor 1 (VT1) is connected to the collector of the second transistor 2 (VT2), forming a second common point 11, and their common input is designed to connect to the terminals of the second stator winding 6 (B) and the third stator winding 7 (C) and connected to the common output of the emitter of the third transistor 3 (VT3) and the collector of the fourth transistor 4 (VT4) of the second pair of semiconductor switches. Moreover, in the second pair of semiconductor switches of the second reversible semiconductor switch, the emitter of transistor 3 (VT3) is connected to the collector of transistor 4 (VT4) with the formation of the first common point 12, and their common output is intended for connection with the terminals of the second stator winding 6 (B) and the third stator winding 7 (C); the collector of the third transistor 3 (VT3) is connected to the emitter of the fourth transistor 4 (VT4), forming a second common point 13, and their common input is designed to connect to the terminals of the first stator winding 5 (A) and the third stator winding 7 (C).

Using vectorial-algorithmic control of a three-phase asynchronous electric motor, it is possible to implement the proposed device when powered by a single-phase alternating voltage network by creating two types of rotating stator fields - by going through six or eight consecutive fixed positions of the magnetic flux vector of a circular rotating field of the motor stator.

The operation of the semiconductor device of the capacitorless start of a three-phase asynchronous electric motor from a single-phase supply network is as follows.

To ensure rotation of the magnetic flux vector of the stator field of a three-phase asynchronous electric motor in accordance with the vector diagram shown in Fig. 2, in the sequence I-II-III-IV-V-VI, it is necessary to apply control pulses to transistors 1 (VT1), 2 ( VT2), 3 (VT3), 4 (VT4) in the following order:

- at the first instant t1 (Fig. 4) of the switching transistor 4 VT4 is operating (Fig. 1), thus the winding 7 (C) is shunted, forming the I fixed position of the stator magnetic field (Fig. 2);

- at the second switching moment t2 (Fig. 4), the transistor 1 (VT1) opens, and the transistor 4 (VT4) (Fig. 1) continues to work, thus windings 6 (B) and 7 (C) are shunted, forming a II fixed position the magnetic field of the stator (Fig. 2);

- at the third instant t3 (Fig. 4) of the switching transistor 1 (VT1) continues to work, and the transistor 4 (VT4) (Fig. 1) is closed, thus winding 6 (B) is shunted, forming a III fixed position of the stator magnetic field (Fig. .2);

- at the fourth switching moment t4 (Fig. 4), the transistor 1 (VT1) closes and the transistor 3 (VT3) opens (Fig. 1), thus winding 7 (C) is shunted, forming an IV fixed position of the stator magnetic field (Fig. 2 );

- at the fifth instant t5 (Fig. 4) of the switching transistor 2 (VT2) opens, and the transistor 3 (VT3) (Fig. 1) continues to work, thus windings 6 (B) and 7 (C) are shunted, forming a V fixed position the magnetic field of the stator (Fig. 2);

- at the sixth switching moment t6 (Fig. 4), the transistor 2 (VT2) continues to work, and the transistor 3 (VT3) (Fig. 1) is closed, thus winding 6 (B) is shunted, forming a VI fixed position of the stator magnetic field (Fig. . 2);

- at the seventh moment t7 (Fig. 4) of the switching transistor 4 (VT4) is operating (Fig. 1), thus winding 7 (C) is shunted, forming the I fixed position of the stator magnetic field (Fig. 2). thus begins a new cycle of timing.

In order to ensure rotation of the magnetic flux vector of the stator field of a three-phase asynchronous electric motor in accordance with the vector diagram shown in FIG. 5, in the sequence I-II-III-IV-V-VI-VII-VIII, it is necessary to apply control pulses to transistors 1 (VT1), 2 (VT2), 3 (VT3), 4 (VT4) in the following order:

- at the first instant t1 (Fig. 5) of the switching transistor 4 (VT4) is operating (Fig. 1), thus winding 7 (C) is shunted, forming the I fixed position of the stator magnetic field (Fig. 3);

- at the second instant t2 (Fig. 5) of the switching transistor 4 (VT4) is closed (Fig. 1), thus the current flows through the windings 5 (A), 6 (B) and 7 (C), forming a II fixed position of the magnetic field stator (Fig. 3);

- at the third instant t3 (Fig. 5) of the switching transistors 1 (VT1) and 4 (VT4) open (Fig. 1), thus windings 6 (B) and 7 (C) are shunted, forming a III fixed position of the stator magnetic field ( Fig. 3);

- at the fourth moment t4 (Fig. 5), the transistor 1 (VT1) continues to work, and the transistor 4 (VT4) (Fig. 1) is closed, thus winding 6 (B) is shunted, forming an IV fixed position of the stator field (Fig. 3) );

- at the fifth moment t5 (Fig. 5), the transistor 1 (VT1) closes and the transistor 3 (VT3) opens (Fig. 1), thus winding 7 (C) is shunted, forming a V fixed position of the stator magnetic field (Fig. 3) ;

- at the sixth moment t6 (Fig. 5), the transistor 3 (VT3) is closed (Fig. 1), so the current flows through the windings 5 (A), 6 (B) and 7 (C), forming a VI fixed position of the stator magnetic field (Fig. 3);

- at the seventh time moment t7 (Fig. 5) of time, transistor 2 (VT2) and transistor 3 (VT3) open (Fig. 1), thus windings 6 (B) and 7 (C) are shunted, forming a VII fixed position of the stator magnetic field (Fig. 3);

- at the eighth moment t8 (Fig. 5), the transistor 2 (VT2) continues to work, and the transistor 3 (VT3) (Fig. 1) is closed, thus winding 6 (B) is shunted, forming a VIII fixed position of the stator field (Fig. 3) );

- at the ninth moment t9 (Fig. 5) of the switching transistor 4 (VT4) is operating (Fig. 1), thus winding 7 (C) is shunted, forming the I fixed position of the stator magnetic field (Fig. 3). Thus begins a new cycle of timing.

Thus, by increasing the number of fixed vectors, it is possible to create a more uniform rotating magnetic field of the stator, which allows you to increase the moment developed by the electric motor, and therefore, increase the power taken from the shaft of the electric motor.

Claims (1)

A semiconductor device for the capacitorless start of a three-phase asynchronous motor from a single-phase supply network, containing two reversing semiconductor switches, designed to connect to the stator windings of a three-phase asynchronous electric motor connected in a "triangle" circuit, and made on pairs of semiconductor switches that are npn transistors, while a pair of semiconductor keys the collector of the first transistor is combined with the emitter of the second transistor in the first common the point and their common input is designed to connect to the phase of the supply network, the emitter of the first transistor is combined with the collector of the second transistor to the second common point, in the second pair of semiconductor keys the emitter of the third transistor is combined with the collector of the fourth transistor to the first common point and their common output is used to connect with the findings of the second and third stator windings, and the collector of the third transistor is combined with the emitter of the fourth transistor at the second common point, the common output of the first and third stator circuits the drain is connected to zero of the supply network, characterized in that in the first pair of semiconductor switches the common input of the collector of the first transistor and emitter of the second transistor is designed to connect to the terminals of the first and second stator windings, and the common input of the emitter of the first transistor and collector of the second transistor the findings of the second and third stator windings and is connected to a common input of the emitter of the third transistor and the collector of the fourth transistor of the second pair of semiconductor switches, in which The input of the collector of the third transistor and emitter of the fourth transistor is intended for connection with the terminals of the first and third stator windings.

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