RU221498U1 - Device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network - Google Patents

Abstract

The utility model relates to starting devices driven by a single-phase AC network, and can be used in AC electric drives to start single-phase two-winding asynchronous motors that do not require rotation speed control from a single-phase network. The technical result of the utility model is to increase reliability and energy efficiency by reducing the energy consumption of a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network. The device contains two pairs of semiconductor switches, powered by a single-phase alternating current network, intended for connection to a load, which is the stator windings of a single-phase two-winding asynchronous electric motor. Two transistors and two diodes are used as each of the semiconductor switches. In the first semiconductor switch of the first pair, the drain of the first transistor is connected to the cathode of the first diode and to the phase of a single-phase AC network, the drain of the second transistor is connected to the cathode of the second diode and to the end of the first stator winding, the sources of the first and second transistors are combined and connected to the anodes of the first and second diodes. In the second semiconductor switch of the first pair, the drain of the third transistor is connected to the cathode of the third diode and to the zero of a single-phase AC network, the drain of the fourth transistor is connected to the cathode of the fourth diode and to the end of the first stator winding, the sources of the third and fourth transistors are combined and connected to the anodes of the third and fourth diodes. In the third semiconductor switch of the second pair, the drain of the fifth transistor is connected to the cathode of the fifth diode and to the phase of a single-phase alternating current network, the drain of the sixth transistor is connected to the cathode of the sixth diode and to the beginning of the first stator winding, the sources of the fifth and sixth transistors are combined and connected to the anodes of the fifth and sixth diodes. In the fourth semiconductor switch of the second pair, the drain of the seventh transistor is connected to the cathode of the seventh diode and to the zero of a single-phase AC network, the drain of the eighth transistor is connected to the cathode of the eighth diode and to the beginning of the first stator winding, the sources of the seventh and eighth transistors are combined and connected to the anodes of the seventh and eighth diodes. The beginning of the second stator winding is connected to the supply line phase, the end of the second stator winding is connected to the supply line neutral. It provides the ability to both start, operate and reverse the engine, providing higher reliability and energy efficiency. 5 ill.

Description

The utility model relates to starting devices driven by a single-phase AC network, and can be used in AC electric drives to start single-phase two-winding asynchronous motors that do not require rotation speed control from a single-phase network.

A device is known for starting a single-phase two-winding asynchronous motor from a single-phase network using a capacitor shift in the stator circuit, providing power from a single-phase network of an asynchronous motor, in which, to obtain a rotating stator field, one winding of the motor is connected to a single-phase network through capacitors, and the other winding is connected directly to the network (Kopylov I.P. Electrical machines. Textbook for universities / I.P. Kopylov. - M.: Higher School, 2006. - P. 343, Fig. 3.96).

The disadvantages of the described device for starting a single-phase two-winding asynchronous motor from a single-phase network using capacitor shift in the stator circuit are low reliability and increased dimensions due to the need to use high-capacity paper capacitors, and the inability to reverse the motor, since this requires design changes.

The closest to the proposed utility model in terms of technical essence and achieved result (prototype) is a reversible capacitorless starting device for a single-phase two-winding asynchronous motor, containing two pairs of semiconductor switches, which are used as transistors, as well as two stator windings. In this case, in the first pair of semiconductor switches, the combined collectors of the first and second transistor are connected to the beginning of the first stator winding, the emitter of the first transistor is connected to the phase of the supply network, the emitter of the second transistor is connected to the zero of the supply network, in the second pair of semiconductor switches, the combined collectors of the third and fourth transistor are connected to the end of the first stator winding, the emitter of the third transistor is connected to the supply network phase, the emitter of the fourth transistor is connected to the supply network zero, the beginning of the second stator winding is connected to the supply network phase, and the end of the second stator winding is connected to the supply network zero (RU patent No. 157687, IPC N02R 1/42 (2006.01), N02R 27/04 (2006.01), publication date 12/10/2015).

The disadvantages of this reversible capacitorless starting device for a single-phase two-winding asynchronous motor are low reliability due to increased heating due to the consumption of control current in the switching mode due to the operation of bipolar transistors on alternating current, as well as increased energy consumption due to the use of bipolar transistors, which require control current to maintain transistors in the on state.

The technical problem, the solution of which is provided by the implementation of the utility model, is to increase reliability and energy efficiency by reducing the energy consumption of a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network.

The solution to this technical problem is achieved by the fact that in a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network, containing two pairs of semiconductor switches, the first and second stator windings, the beginning of the second stator winding is connected to the supply line phase, the end of the second stator winding is connected to zero supply network, the first outputs of the first semiconductor switch of the first pair and the third semiconductor switch of the second pair are connected to the phase of the supply network, the first outputs of the second semiconductor switch of the first pair and the fourth semiconductor switch of the second pair are connected to the zero of the supply network, the combined second outputs of the first and second semiconductor switches of the first pairs are connected to the end of the first stator winding, and the combined second outputs of the third and fourth semiconductor switches of the second pair are connected to the beginning of the first stator winding, according to the utility model, two transistors and two diodes are used as each of the semiconductor switches, while in the first semiconductor switch the drain of the first transistor is connected to the cathode of the first diode and to the phase of a single-phase alternating current network, the drain of the second transistor is connected to the cathode of the second diode and to the end of the first stator winding, the sources of the first and second transistors are combined and connected to the anodes of the first and second diodes, in the second semiconductor switch the drain of the third transistor is connected to the cathode of the third diode and to the zero of a single-phase AC network, the drain of the fourth transistor is connected to the cathode of the fourth diode and to the end of the first stator winding, the sources of the third and fourth transistors are combined and connected to the anodes of the third and fourth diodes, in the third semiconductor switch the drain of the fifth transistor is connected to the cathode of the fifth diode and to the phase of a single-phase AC network, the drain of the sixth transistor is connected to the cathode of the sixth diode and to the beginning of the first stator winding, the sources of the fifth and sixth transistors are combined and connected to the anodes of the fifth and sixth diodes, in the fourth semiconductor switch the drain of the seventh transistor is connected to the cathode of the seventh diode and to the zero of a single-phase alternating current network, the drain of the eighth transistor is connected to the cathode of the eighth diode and to the beginning of the first stator winding, the sources of the seventh and eighth transistors are combined and connected to the anodes of the seventh and eighth diodes.

IGBT or MOSFET transistors can be used as transistors.

Increasing the reliability and energy efficiency of a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network is due to the use of transistors in each semiconductor switch that are controlled by potential rather than current, without the need to take into account the polarity of the voltage passing through the transistors.

The proposed utility model is illustrated by drawings, where Fig. 1 shows a schematic electrical diagram of a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network; Fig. 2 shows a vector diagram of the circular rotating field of the stator of the engine, consisting of four fixed positions of the magnetic induction vector of the stator field, when rotating clockwise; in fig. Figure 3 shows the flow of current through the stator windings at different times, as well as the phase-by-phase change in the magnetic flux in the stator windings in accordance with the vector diagram shown in Fig. 2; Fig. 4 shows a vector diagram of the circular rotating field of the stator of the engine, consisting of four fixed positions of the magnetic induction vector of the stator field, when rotating counterclockwise; in fig. Figure 5 shows the flow of current through the stator windings at different times, as well as the phase-by-phase change in the magnetic flux in the stator windings in accordance with the vector diagram shown in Fig. 4.

In addition, the following symbols are used in the drawing:

F - phase;

0 - zero;

L1, L2 - stator windings of the electric motor;

VT1 - VT8 - transistors;

I, II, III, IV - successive fixed positions of the magnetic flux vector of the circular rotating field of the stator of an asynchronous motor;

Umains - supply voltage;

arcuate lines with an arrow - the direction of rotation of the stator magnetic field;

t1, t2…t4 - moments of switching time of transistors;

and - source;

s - drain;

a - anode;

k - cathode;

straight lines with arrows - directions of the magnetic induction vector of the circular rotating field of the engine stator.

A device for capacitor-free starting of a single-phase two-winding asynchronous electric motor from a single-phase network contains two pairs of semiconductor switches powered by a single-phase alternating current network, intended for connection to a load representing the stator windings of a single-phase two-winding asynchronous electric motor. Two transistors and two diodes are used as each of the semiconductor switches. In the first semiconductor switch 1 (K1) of the first pair, the drain of the first 2 (VT1) transistor is connected to the cathode of the first diode 3 (VD1) and with the phase of a single-phase AC network, the drain of the second 4 (VT2) transistor is connected to the cathode of the second diode 5 (VD2) and with the end 6 (C2) of the first stator winding 7 (L1), the sources of the first 2 (VT1) and second 4 (VT2) transistors are combined and connected to the anodes of the first 3 (VD1) and second 5 (VD2) diodes. In the second semiconductor switch 8 (K2) of the first pair, the drain of the third 9 (VT3) transistor is connected to the cathode of the third 10 (VD3) diode and to the zero of a single-phase AC network, the drain of the fourth 11 (VT4) transistor is connected to the cathode of the fourth 12 (VD4) diode and with the end 6 (C2) of the first stator winding 7 (L1), the sources of the third 9 (VT3) and fourth 11 (VT4) transistors are combined and connected to the anodes of the third 10 (VD3) and fourth 12 (VD4) diodes. In the third semiconductor switch 13 (K3) of the second pair, the drain of the fifth 14 (VT5) transistor is connected to the cathode of the fifth 15 (VD5) diode and to the phase of a single-phase AC network, the drain of the sixth 16 (VT6) transistor is connected to the cathode of the sixth 17 (VD6) diode and with the beginning 18 (C1) of the first stator winding 7 (L1), the sources of the fifth 14 (VT5) and sixth 16 (VT6) transistors are combined and connected to the anodes of the fifth 15 (VD5) and sixth 17 (VD6) diodes. In the fourth semiconductor switch 19 (K4) of the second pair, the drain of the seventh 20 (VT7) transistor is connected to the cathode of the seventh 21 (VD7) diode and to the zero of a single-phase AC network, the drain of the eighth 22 (VT8) transistor is connected to the cathode of the eighth 23 (VD8) diode and with the beginning 18 (C1) of the first stator winding 7 (L1), the sources of the seventh 21 (VT7) and eighth 22 (VT8) transistors are combined and connected to the anodes of the seventh 20 (VD7) and eighth 23 (VD8) diodes. The beginning 24 (C3) of the second stator winding 25 (L2) is connected to the supply line phase, the end 26 (C4) of the second stator winding 25 (L2) is connected to the supply line zero.

The operation of a device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network is carried out as follows. To ensure that the magnetic induction vector of the rotating circular field of the motor stator rotates clockwise, in accordance with the vector diagram shown in Fig. 2, it is necessary to apply control signals to the gates of transistors 2 (VT1), 4 (VT2), 9 (VT3), 11 (VT4), 14 (VT5), 16 (VT6), 21 (VT7), 22 (VT8) as follows order (Fig. 3).

1. In the positive half-wave of the supply voltage, in the period from 0 to t1, transistors 2 (VT1) and 22 (VT8) open, providing the first I fixed position of the magnetic induction vector of the stator field when current flows through windings 7 (L1) to the right and 25 ( L2) down in the direction shown by the arrows.

2. During the positive half-wave of the supply voltage, in the period from t1 to t2, transistors 14 (VT5) and 11 (VT4) open, while transistors 2 (VT1) and 22 (VT8) close, providing a second II fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the left and 25 (L2) down in the direction shown by the arrows.

3. During the negative half-wave of the supply voltage, in the period from t2 to t3, transistors 21 (VT7) and 4 (VT2) open, while transistors 14 (VT5) and 11 (VT4) close, providing the third III fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the left and 25 (L2) up in the direction shown by the arrows.

4. In the negative half-wave of the supply voltage, in the period from t3 to t4, transistors 9 (VT3) and 16 (VT6) open, while transistors 21 (VT7) and 4 (VT2) close, providing the fourth IV fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the right and 25 (L2) upward in the direction shown by the arrows.

The stator field turns out to be rotating, circular, spatial, and time-varying. When the next positive half-wave passes, the cycle repeats, ensuring clockwise rotation of the stator field.

To ensure that the magnetic induction vector of the rotating circular field of the motor stator rotates counterclockwise, in accordance with the vector diagram shown in Fig. 4, it is necessary to apply control signals to the gates of transistors 2 (VT1), 4 (VT2), 9 (VT3), 11 (VT4), 14 (VT5), 16 (VT6), 21 (VT7), 22 (VT8) as follows order (Fig. 5).

1. In the positive half-wave of the supply voltage, in the period from 0 to t1, transistors 14 (VT5) and 11 (VT4) open, providing the first I fixed position of the magnetic induction vector of the stator field when current flows through windings 7 (L1) to the left and 25 ( L2) down in the direction shown by the arrows.

2. In the positive half-wave of the supply voltage, in the period from t1 to t2, transistors 2 (VT1) and 22 (VT8) open, while transistors 14 (VT5) and 11 (VT4) close, providing a second II fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the right and 25 (L2) down in the direction shown by the arrows.

3. In the negative half-wave of the supply voltage, in the period from t2 to t3, transistors 9 (VT3) and 16 (VT6) open, while transistors 2 (VT1) and 22 (VT8) close, providing the third III fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the right and 25 (L2) upward in the direction shown by the arrows.

4. In the negative half-wave of the supply voltage, in the period from t3 to t4, transistors 21 (VT7) and 4 (VT2) open, while transistors 9 (VT3) and 16 (VT6) close, providing the fourth IV fixed position of the magnetic induction field vector stator when current flows through windings 7 (L1) to the left and 25 (L2) up in the direction shown by the arrows.

The stator field turns out to be rotating, circular, spatial, and time-varying. When the next positive half-wave passes, the cycle repeats, ensuring counterclockwise rotation of the stator field.

Thus, the device for capacitorless starting of a single-phase two-winding asynchronous electric motor from a single-phase network allows both starting, operating and reversing the motor.

Based on the foregoing, we can conclude that the proposed utility model has advantages over the known ones due to higher reliability and energy efficiency.

Claims (1)

A device for capacitor-free starting of a single-phase two-winding asynchronous electric motor from a single-phase network, containing two pairs of semiconductor switches, the first and second stator windings, with the beginning of the second stator winding connected to the supply network phase, the end of the second stator winding connected to the supply network zero, the first outputs of the first semiconductor switch of the first pair and the third semiconductor switch of the second pair are connected to the phase of the supply network, the first outputs of the second semiconductor switch of the first pair and the fourth semiconductor switch of the second pair are connected to the zero of the supply network, the combined second outputs of the first and second semiconductor switches of the first pair are connected to the end of the first stator winding, and the combined second outputs of the third and fourth semiconductor switches of the second pair are connected to the beginning of the first stator winding, characterized in that two transistors and two diodes are used as each of the semiconductor switches, while in the first semiconductor switch the drain of the first transistor is connected to the cathode of the first diode and to phase of a single-phase AC network, the drain of the second transistor is connected to the cathode of the second diode and to the end of the first stator winding, the sources of the first and second transistors are combined and connected to the anodes of the first and second diodes, in the second semiconductor switch the drain of the third transistor is connected to the cathode of the third diode and to zero of a single-phase AC network, the drain of the fourth transistor is connected to the cathode of the fourth diode and to the end of the first stator winding, the sources of the third and fourth transistors are combined and connected to the anodes of the third and fourth diodes, in the third semiconductor switch the drain of the fifth transistor is connected to the cathode of the fifth diode and to phase of a single-phase alternating current network, the drain of the sixth transistor is connected to the cathode of the sixth diode and to the beginning of the first stator winding, the sources of the fifth and sixth transistors are combined and connected to the anodes of the fifth and sixth diodes, in the fourth semiconductor switch the drain of the seventh transistor is connected to the cathode of the seventh diode and to zero of a single-phase AC network, the drain of the eighth transistor is connected to the cathode of the eighth diode and to the beginning of the first stator winding, the sources of the seventh and eighth transistors are combined and connected to the anodes of the seventh and eighth diodes.