RU157687U1 - REVERSE CONDENSOR-FREE DEVICE STARTING A SINGLE-PHASE TWO-WAY ASYNCHRONOUS MOTOR - Google Patents

Abstract

A reversible non-capacitor starting device for a single-phase two-winding induction motor containing two pairs of semiconductor switches, a first and second stator winding, the combined collectors of the first and second semiconductor switches of the first pair connected to the first terminal of the first stator winding, and the combined collectors of the third and fourth semiconductor switches of the second pair connected to the second output of the first stator winding, emitters of the first semiconductor switch of the first pair and the third semiconductor the second key of the second pair are connected to the mains phase, and the emitters of the second semiconductor key of the first pair and the fourth semiconductor key of the second pair are connected to zero of the mains, characterized in that the first terminal of the second stator winding is connected to the phase of the mains, and the second terminal of the second stator winding connected to zero power supply.

Description

The proposed 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 asynchronous motors from a single-phase network that do not require speed control.

A device is known for starting a single-phase asynchronous motor from a single-phase network using a capacitor shift in the stator circuit, powered by a single-phase network of a single-phase asynchronous motor, in which, to obtain a rotating stator field, one winding of a single-phase asynchronous motor is connected to a single-phase network via capacitors, and the other winding is directly to a single-phase network (IP Kopylov Electric machines. Textbook for universities / IP Kopylov. - M.: Higher school, 2006. - S. 343, Fig. 3.96).

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

The closest to the proposed utility model in terms of technical nature and the achieved result (prototype) is a frequency converter driven by a single-phase AC network for starting a single-phase asynchronous motor containing four pairs of semiconductor switches, as well as the first and second stator windings. Eight transistors are used as semiconductor switches, passing current in both directions and designed to operate in key mode. The combined collectors of the first and second semiconductor switches of the first pair are connected to the first terminal of the first stator winding, the combined collectors of the third and fourth semiconductor switches of the second pair are connected to the second terminal of the first stator winding, the combined collectors of the fifth and sixth semiconductor switches of the third pair are connected to the first terminal of the second stator windings, combined collectors of the seventh and eighth semiconductor switches of the second pair are connected to the second terminal of the second winding of st ator. The emitters of the first semiconductor key of the first pair, the third semiconductor key of the second pair, the fifth semiconductor key of the third pair and the seventh semiconductor key of the fourth pair are connected to the mains phase, and the emitters of the second semiconductor key of the first pair, the fourth semiconductor key of the second pair, the sixth semiconductor key of the third pair and of the eighth semiconductor key of the fourth pair are connected to zero power supply (patent RU No. 109938, IPC H02P 27/04 (2006.01), H02P 27/18 (2006.01), H02M 5/275 (2006.01), H02M 5/297 (2006.01 )).

The main disadvantages of this frequency converter driven by a single-phase AC network for starting a single-phase asynchronous motor are reduced reliability, increased dimensions and cost due to the introduction of a large number of semiconductor switches, which are used as eight transistors connected to two stator windings and a supply network.

The proposed utility model solves the problem of starting a single-phase two-winding asynchronous motor from a single-phase AC network with a decrease in size and increased reliability of the device through the use of two semiconductor switches associated with only one stator winding and a supply network, connecting the second stator winding to the supply network directly, and also with increased efficiency by reducing energy consumption with semiconductor switches.

To solve this problem, in a reversible non-capacitor starting device for a single-phase two-winding induction motor containing two pairs of semiconductor switches, the first and second stator windings, the combined collectors of the first and second semiconductor switches of the first pair connected to the first output of the first stator winding, and the combined collectors of the third and fourth the semiconductor switches of the second pair are connected to the second terminal of the first stator winding, the emitters of the first semiconductor switch are the first pair and the third semiconductor key of the second pair are connected to the phase of the mains, and the emitters of the second semiconductor key of the first pair and the fourth semiconductor key of the second pair are connected to zero of the mains, according to a utility model, the first terminal of the second stator winding is connected to the phase of the mains, and the second terminal the second stator winding is connected to the supply network zero.

The proposed utility model is illustrated in the drawing, where in FIG. 1 shows a circuit diagram of a reversible non-capacitor starting device for a single-phase two-winding induction motor; in FIG. 2 is a vector diagram of a circular rotating field of a motor stator, consisting of four fixed positions of the magnetic flux, while simultaneously turning on two stator windings of the motor starting the engine; in FIG. 3 - phase-by-phase change of the magnetic flux in the stator windings at a frequency freg = fnetwork in accordance with the vector diagram shown in FIG. 2; in FIG. 4 shows the directions of the magnetic flux and the current flowing through the stator windings of the motor in accordance with the vector diagram shown in FIG. 2; in FIG. 5 is a vector diagram of a circular rotating field of a motor stator, consisting of four fixed positions of the magnetic flux, while turning on two motor stator windings that reverse the motor; FIG. 6 - phase-by-phase change of the magnetic flux in the stator windings at a frequency freg = fnetwork in accordance with the vector diagram depicted in FIG. 5; in FIG. 7 shows the directions of the magnetic flux and the current flowing through the stator windings of the motor in accordance with the vector diagram depicted in FIG. 5.

In addition, the drawing shows the following:

F - phase;

0 is zero;

E - emitter;

K - collector;

- C1-C4 - conclusions of the corresponding stator windings of a single-phase two-winding asynchronous motor;

VT1-VT4 - transistors operating in key mode;

- I, II, III, IV - sequential fixed positions of the magnetic flux vector of the circular rotating field of the stator of a single-phase asynchronous motor;

- straight lines with arrows - the direction of the magnetic flux vector of the circular rotating field of the stator of a single-phase asynchronous motor;

- Uset = f (t) - change in the supply voltage of the AC network in the second stator winding in time;

- straight lines with arrows along the stator windings of a single-phase asynchronous motor - the direction of magnetic flux and current in the stator windings;

- VT1, VT2, VT3, VT4 - open transistors for the first winding of a single-phase two-winding asynchronous motor at each moment in time to ensure rotation of the stator field.

A reversible non-capacitor starting device for a single-phase two-winding induction motor contains two pairs of semiconductor switches, and each of the switches uses two transistors that transmit current in both directions and are designed to operate in key mode.

In the first pair of semiconductor switches, the emitter of the first transistor 1 (VT1) is connected to the phase of the supply network, and the emitter of the second transistor 2 (VT2) is connected to zero of the supply network. The collector of the first transistor 1 (VT1) and the collector of the second transistor 2 (VT2) are combined and connected to the first terminal 3 (C1) of the first stator winding.

In the second pair of semiconductor switches, the emitter of the third transistor 4 (VT3) is connected to the phase of the supply network, and the emitter of the fourth transistor 5 (VT4) is connected to zero of the supply network. The collector of the third transistor 4 (VT3) and the collector of the fourth transistor 5 (VT4) are combined and connected to the second terminal 6 (C2) of the first stator winding.

The second stator winding is connected directly to the network, and the first terminal 7 (C3) is connected to the phase of the supply network, and the second terminal 8 (C4) is connected to zero of the supply network.

Using a reversible non-capacitor starting device for a single-phase two-winding induction motor, it is possible to vectorly control a single-phase two-winding asynchronous electric motor, creating several types of rotating stator fields: passing four consecutive fixed positions of the magnetic flux vector of a circular rotating field while simultaneously turning on two motor stator windings that start the engine (see Fig. 2), and the passage of four consecutive GOVERNMENTAL positions of the magnetic flux of the circular rotating field is turned on while two stator windings of the motor, the motor carrying reverse (see. Fig. 5).

Vector control of a single-phase two-winding induction motor by passing four consecutive fixed positions of the stator field magnetic flux vector for one revolution of the motor while simultaneously turning on the two stator windings of the motor that start the engine is performed as follows.

To ensure the rotation of the magnetic flux vector of the circular rotating field of the stator of a single-phase induction motor in accordance with the vector diagram shown in FIG. 2, taking into account the constant current flow through the second stator winding, it is necessary to apply control pulses to the transistors in the following order:

- in the first positive quarter of the supply voltage period, transistor 4 (VT3) and transistor 2 (VT2) open, providing current flow through the first stator winding, - I fixed position of the stator field magnetic flux vector;

- in the second positive quarter of the supply voltage period, transistor 4 (VT3) and transistor 2 (VT2) close and transistor 1 (VT1) and transistor 5 (VT4) open, ensuring the flow of current along the first stator winding, - II fixed position of the magnetic field flux vector stator;

- in the first negative quarter of the supply voltage period, transistor 1 (VT1) and transistor 5 (VT4) close and transistor 2 (VT2) and transistor 4 (VT3) open, providing current flow along the first stator winding, - III fixed position of the magnetic field flux vector stator;

- in the second negative quarter of the supply voltage period, transistor 2 (VT2) and transistor 4 (VT3) are closed and transistor 5 (VT4) and transistor 1 (VT1) are opened, providing current flow through the first stator winding, - IV fixed position of the magnetic field flux vector stator.

With these sequences of switching on transistors, the proposed reversible non-capacitor starting device for a single-phase two-winding induction motor allows the engine to start.

Vector control of a single-phase two-winding induction motor by passing four consecutive fixed positions of the stator field magnetic flux vector for one revolution of the motor while simultaneously turning on two stator windings of the motor that reverse the motor is performed as follows.

In order to ensure rotation of the magnetic flux vector of the circular rotating field of the stator of a single-phase two-winding induction motor in accordance with the vector diagram shown in FIG. 5, taking into account the constant current flow through the second stator winding, it is necessary to apply control pulses to the transistors in the following order:

- in the first positive quarter of the supply voltage period, transistor 1 (VT1) and transistor 5 (VT4) open, providing current flow through the first stator winding, - I fixed position of the stator field magnetic flux vector;

- in the second positive quarter of the supply voltage period, transistor 1 (VT1) and transistor 5 (VT4) close and transistor 4 (VT3) and transistor 2 (VT2) open, providing current flow along the first stator winding, - II fixed position of the magnetic field flux vector stator;

- in the first negative quarter of the supply voltage period, transistor 4 (VT3) and transistor 2 (VT2) close and transistor 5 (VT4) and transistor 1 (VT1) open, providing current flow through the first stator winding, - III fixed position of the magnetic field flux vector stator;

- in the second negative quarter of the supply voltage period, transistor 5 (VT4) and transistor 1 (VT1) close and transistor 2 (VT2) and transistor 4 (VT3) open, providing current flow through the first stator winding, - IV fixed position of the magnetic field flux vector stator.

With these transistor switching sequences, this reversible non-capacitor starting device for a single-phase two-winding asynchronous motor allows the motor to be reversed.

Thus, with the above-described transistor switching sequences, this reversible non-capacitor starting device for a single-phase two-winding induction motor allows both starting, operation, and reverse of 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 economy, as well as small dimensions

Claims (1)

A reversible non-capacitor starting device for a single-phase two-winding induction motor containing two pairs of semiconductor switches, a first and second stator winding, the combined collectors of the first and second semiconductor switches of the first pair connected to the first terminal of the first stator winding, and the combined collectors of the third and fourth semiconductor switches of the second pair connected to the second output of the first stator winding, emitters of the first semiconductor switch of the first pair and the third semiconductor the second key of the second pair are connected to the phase of the mains, and the emitters of the second semiconductor key of the first pair and the fourth semiconductor key of the second pair are connected to zero of the mains, characterized in that the first terminal of the second stator winding is connected to the phase of the mains, and the second terminal of the second stator winding connected to zero power supply.

Images