RU2439774C1 - Semiconductor gear guided by mains for speed control of one-phase double-winding asynchronous motor - Google Patents

Abstract

FIELD: electricity. ^ SUBSTANCE: semiconductor gear guided by mains for speed control of one-phase double-winding asynchronous motor is related to frequency converters and intended for use with AC controlled electric drive for supply from one-phase mains of one-phase double-winding asynchronous motor. Three inverse semi-conductor switch-boards are made at semi-conductor switch based on four thyristors. One-phase AC voltage is used. At each switch-board anode of the first thyristor and cathode of the second thyristor are connected to zero lead of AC supply mains and anode of the third thyristor and cathode of the fourth thyristor are connected to phase of AC supply mains. Common mid point of the first semi-conductor switch-board that connects in this switchboard cathode of the first thyristor with anode of the second thyristor and cathode of the third thyristor with anode of the fourth thyristor is connected to the first united output of stator windings of single-phase double-winding asynchronous motor. Common mid point of the second semi-conductor switch-board that connects in this switchboard cathode of the first thyristor with anode of the second thyristor and cathode of the third thyristor with anode of the fourth thyristor is connected to the second united output of stator windings of single-phase double-winding asynchronous motor. Common mid point of the third semi-conductor switch-board that connects in this switchboard cathode of the first thyristor with anode of the second thyristor and cathode of the third thyristor with anode of the fourth thyristor is connected to the second united output of stator windings of single-phase double-winding asynchronous motor. ^ EFFECT: power supply of single-phase double-winding asynchronous motor is provided from single-phase mains with option of low-frequency control of its rotation speed in broad band. ^ 9 dwg

Description

The present invention relates to frequency converters and can be used in a controlled AC drive for power from a single-phase network of a single-phase two-winding asynchronous electric motor.

A single-phase capacitor motor is known in which the first output of the first winding is connected to zero of the supply network, and the second output of the first winding is connected to the first output of the second winding and to the phase of the supply network. The second output of the second winding is connected to the first capacitor plate. The second lining of the capacitor is connected to zero of the supply network (IP Kopylov Electric machines. Textbook for universities / IP Kopylov. M .: Higher school, 2006. - P.343, Fig. 3.96).

The disadvantages of this device are the lack of the ability to control the speed of rotation of the electric motor, increased dimensions and low efficiency, as well as low reliability due to the need to use paper capacitors of large capacity.

The closest to the proposed invention by technical nature and the achieved result (prototype) is a single-phase bridge circuit of a current inverter, with which the frequency of the voltage supplied to each of the motor windings is controlled, which contains reversed semiconductor switches made on semiconductor switches implemented on thyristors, connected to the DC supply network, as well as a smoothing power reactor and a blocking capacitor connected to the coil engine track. Moreover, each reversible semiconductor switch is implemented on four thyristors. One output of the smoothing power reactor is connected to the plus of the DC supply network, and the second output is connected to the anodes of the two thyristors. The cathodes of these thyristors are connected to the first and second outputs of one of the stator windings of the electric motor, respectively, as well as to the anodes of another pair of thyristors. The cathodes of this pair of thyristors are connected to the minus of the DC supply network. The first and second capacitor plates are connected to the first and second terminals of one of the motor windings, respectively (V. A. Labuntsov, G. A. Rivkin, G. I. Shevchenko. Autonomous thyristor inverters / M.: Energy, 1967, - M. - L., p.20, fig. 7c).

The main disadvantages of the described single-phase bridge current inverter - frequency converter are the inability to provide direct power to the single-phase two-winding induction motor from an alternating voltage of a single-phase network due to the presence of a direct current source, that is, the need for a rectification device, increased dimensions, as well as low cost and reliability due to the use paper capacitors to provide capacitive locking tori that leads to no danger of closing thyristors when changing direction of current flow through the coil and, as a result, the inverter breakthrough, i.e. short circuit the DC source of power and the availability of smoothing reactors that reduce pulsation of the rectified voltage.

The present invention solves the problem of providing power to a single-phase two-winding asynchronous electric motor from an alternating voltage of a single-phase network with the possibility of low-frequency regulation of the rotation speed of the electric motor while simplifying the power part of the device, reducing the size, increasing the efficiency and reliability of the device.

To solve the problem in a semiconductor gearbox driven by a network for controlling the speed of a single-phase two-winding asynchronous electric motor, which contains reversible semiconductor switches made on semiconductor switches implemented on four thyristors, which are connected to the mains and stator windings of a single-phase two-winding asynchronous motor, according to the invention single-phase alternating voltage and three reversible semiconductor switches. In each switch, the anode of the first thyristor and the cathode of the second thyristor are connected to zero AC voltage supply, and the anode of the third thyristor and cathode of the fourth thyristor are connected to the phase of the AC voltage network. The middle common point of the first semiconductor switch, connecting the cathode of the first thyristor in this switch with the anode of the second thyristor, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the combined first outputs of the stator windings of a single-phase two-winding induction motor. The middle common point of the second semiconductor switch, connecting the cathode of the first thyristor in this switch with the anode of the second thyristor, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the second output of the first stator winding of a single-phase two-winding induction motor. The middle common point of the third semiconductor switch connecting the cathode of the first thyristor to the anode of the second thyristor in this switch, as well as connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the second output of the second stator winding of a single-phase two-winding induction motor.

Low-frequency regulation of the rotation speed of the electric motor is carried out due to the vector-algorithmic switching of thyristors.

The reduction in size, improving the efficiency and reliability of the device is ensured by eliminating the direct current source and smoothing reactors, eliminating locking capacitors in the power part of the device and reducing the consumption of electric energy for capacitor locking.

The use of a network-driven semiconductor reducer to control the speed of a single-phase two-winding asynchronous electric motor causes the creation of various types of rotating stator magnetic fields by algorithmic switching of thyristors, which makes it possible to obtain not only the required current direction in the stator windings, but also the frequency control of the stator rotating magnetic field, and therefore , and motor speed.

The invention is illustrated in the drawing, where Fig. 1 is a circuit diagram of the proposed semiconductor gearbox driven by a network for controlling the speed of a single-phase two-winding asynchronous electric motor; figure 2 is a vector diagram of the rotation of the magnetic flux of the stator field, consisting of three fixed positions; figure 3 is a vector diagram of the rotation of the magnetic flux of the stator field, consisting of four fixed positions; figure 4 is a vector diagram of the rotation of the magnetic flux of the stator field, consisting of six fixed positions; figure 5 is a vector diagram of the rotation of the magnetic flux of the stator field, consisting of eight fixed positions; figure 6 - phase-by-phase change in magnetic flux in the stator windings in accordance with the vector diagram shown in figure 2; in Fig.7 - phase-by-phase change in the magnetic flux in the stator windings in accordance with the vector diagram shown in Fig.3; on Fig - phase-by-phase change in the magnetic flux in the stator windings in accordance with the vector diagram depicted in figure 4; figure 9 - phase-by-phase change in magnetic flux in the stator windings in accordance with the vector diagram shown in figure 5.

In addition, the drawing shows the following:

- U _network - voltage coming from an AC voltage power source;

- t is the current time;

- f - phase;

- About - zero;

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

- L1, L2 - stator windings;

- VS1-VS12 - thyristors;

- 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 double-winding induction motor;

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

- straight lines with arrows - directions of the magnetic flux and current in the stator windings.

A network-driven semiconductor gearbox for controlling the speed of a single-phase two-winding asynchronous electric motor contains three reversible semiconductor switches made on semiconductor switches implemented on four thyristors using a single-phase alternating voltage. These switches are designed for vector-algorithmic switching of the windings of a single-phase two-winding asynchronous motor. In each switch, the anode of the first thyristor and the cathode of the second thyristor are connected to zero AC voltage supply, and the anode of the third thyristor and cathode of the fourth thyristor are connected to the phase of the AC voltage network. The middle common point of the first semiconductor switch, connecting the cathode of the first thyristor in this switch with the anode of the second thyristor, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the combined first outputs of the stator windings of a single-phase two-winding induction motor. The middle common point of the second semiconductor switch, connecting the cathode of the first thyristor in this switch with the anode of the second thyristor, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the second output of the first stator winding of a single-phase two-winding induction motor. The middle common point of the third semiconductor switch connecting the cathode of the first thyristor to the anode of the second thyristor in this switch, as well as connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the second output of the second stator winding of a single-phase two-winding induction motor.

An example of a semiconductor gearbox driven by a network for controlling the speed of a two-phase asynchronous electric motor.

The network-driven semiconductor gearbox for controlling the speed of a single-phase two-winding asynchronous electric motor contains thyristors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (VS1-VS12) connected in opposite parallel two thyristors.

Thus, in the first reversible semiconductor switch, the anode of thyristor 1 (VS1) is connected to the cathode of thyristor 2 (VS2) and their common output is with zero supply voltage of the alternating voltage network; the anode of thyristor 3 (VS3) is connected to the cathode of thyristor 4 (VS4) and their common output is connected to the phase of the ac supply network; the cathode of thyristor 1 (VS1) is connected to the anode of thyristor 2 (VS2) and their common output is with the first output 13 (C1) of the winding 14 (L1) and the first output 15 (C2) of the winding 16 (L2); the cathode of thyristor 3 (VS3) is connected to the anode of thyristor 4 (VS4) and their common output is with the first output 13 (C1) of the first stator winding 14 (L1) and the first output 15 (C2) of the second stator winding 16 (L2). In this case, the middle common point of the first reverse semiconductor switch connecting the cathode of thyristor 1 (VS1) with the anode of thyristor 2 (VS2) and connecting the cathode of thyristor 3 (VS3) with the anode of thyristor 4 (VS4) is connected to the combined first output 13 (C1) of the first the stator winding 14 (L1) and the first output 15 (C2) of the second stator winding 16 (L2).

In the second reversible semiconductor switch, the anode of thyristor 5 (VS5) is connected to the cathode of thyristor 6 (VS6) and their common output is connected to zero of the AC mains; the anode of thyristor 7 (VS7) is connected to the cathode of thyristor 8 (VS8) and their common output is connected to the phase of the ac supply network; the cathode of thyristor 5 (VS5) is connected to the anode of thyristor 6 (VS6) and their common output is with the second output 17 (C3) of the first stator winding 14 (L1); the cathode of thyristor 7 (VS7) is connected to the anode of thyristor 8 (VS8) and their common output is with the second output 17 (C3) of the first stator winding 14 (L1). The middle common point of the second reversing semiconductor switch connecting the cathode of thyristor 5 (VS5) with the anode of thyristor 6 (VS6) and connecting the cathode of thyristor 7 (VS7) with the anode of thyristor 8 (VS8) is connected to the second output 17 (C3) of the first stator windings 14 (L1).

In the third reversing semiconductor switch, the anode of the thyristor 9 (VS9) is connected to the cathode of the thyristor 10 (VS10) and their common output is with zero supply voltage of the AC voltage; the anode of thyristor 11 (VS11) is connected to the cathode of thyristor 12 (VS12) and their common output is connected to the phase of the AC mains; the cathode of thyristor 9 (VS9) is connected to the anode of thyristor 10 (VS10) and their common output is with the second output 18 (C4) of the second stator winding 16 (L2); the cathode of thyristor 11 (VS11) is connected to the anode of thyristor 12 (VS12) and their common output is with the second output 18 (C4) of the second stator winding 16 (L2). The middle common point of the third reversing semiconductor switch connecting the cathode of thyristor 9 (VS9) with the anode of thyristor 10 (VS10) and connecting the cathode of thyristor 11 (VS11) with the anode of thyristor 12 (VS12) is connected to the second output 18 (C4) of the second stator winding 16 (L1).

Using a network-driven semiconductor gearbox to control the speed of a single-phase two-winding asynchronous electric motor, it is possible to carry out vector-algorithmic control of a single-phase two-winding asynchronous electric motor, creating several types of rotating stator fields: passing three, or four, or six, or eight consecutive fixed positions of the magnetic flux vector circular rotating field of a stator motor.

To ensure rotation of the magnetic flux vector of the stator field of a two-phase asynchronous electric motor in accordance with the vector diagram shown in figure 2, in the sequence I-II-III, it is necessary to apply control pulses to thyristors 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (VS1-VS12) in the following order (Fig.6);

- in the positive half-period, at time t ₁ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn on and work, providing I a fixed position of the stator magnetic flux when current flows through winding 14 (L1) in the direction shown in figure 6;

- in the negative half-period, at time t ₂ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn off, thyristors 5 (VS5), 12 (VS12) turn on and work, providing II a fixed position of the stator magnetic flux when current flows through windings 14 (L1), 16 (L2) in the direction shown in figure 6;

- in the next positive half-cycle, at time t _{3 of} alternating voltage, thyristors 5 (VS5), 12 (VS12) turn off, thyristors 7 (VS7), 11 (VS11), 2 (VS2) turn on and work, providing III a fixed magnetic position the stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 6;

- in the next negative half-cycle, at time t _{4 of} alternating voltage, thyristors 7 (VS7), 11 (VS11), 2 (VS2) turn off, thyristors 1 (VS1), 8 (VS8) turn on and work, providing I a fixed magnetic position stator flow when current flows through winding 14 (L1) in the direction shown in FIG. 6;

- in the next positive half-cycle, at time t ₅ , of an alternating voltage, thyristors 1 (VS1), 8 (VS8) turn off, thyristors 7 (VS7), 10 (VS10) turn on and work, providing II a fixed position of the stator magnetic flux when current flows along the windings 14 (L1), 16 (L2) in the direction shown in figure 6;

- in the next negative half-cycle, at time t ₆ , of an alternating voltage, thyristors 7 (VS7), 10 (VS10) turn off, thyristors 5 (VS5), 9 (VS9), 4 (VS4) turn on and work, providing III a fixed magnetic position stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 6.

Starting from the next positive half-cycle, at time t ₇ , the thyristor switching cycle is repeated, providing a circular rotation of the stator field.

To ensure rotation of the magnetic flux vector of the stator field of a single-phase two-winding induction motor in accordance with the vector diagram shown in figure 3, in the sequence I-II-III-IV, it is necessary to apply control pulses to thyristors 1, 2, 3, 4, 5, 6 , 7, 8, 9, 10, 11, 12 (VS1-VS12) in the following order (Fig.7):

- in the positive half-cycle, at time t ₁ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn on and work, providing I a fixed position of the stator magnetic flux when current flows through winding 14 (L1) in the direction shown in figure 7;

- in the negative half-period, at time t ₂ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn off, thyristors 1 (VS1), 12 (VS12) turn on and work, providing II a fixed position of the stator magnetic flux when current flows through winding 16 (L2) in the direction shown in figure 7;

- in the next positive half-cycle, at time t ₃ , of an alternating voltage, thyristors 1 (VS1), 12 (VS12) turn off, thyristors 7 (VS7), 2 (VS2) turn on and work, providing III a fixed position of the stator magnetic flux when current flows winding 14 (L1) in the direction shown in figure 7;

- in the next negative half-cycle, at time t _{4 of} alternating voltage, thyristors 7 (VS7), 2 (VS2) turn off, thyristors 9 (VS9), 4 (VS4) turn on and work, providing IV a fixed position of the stator magnetic flux during current flow winding 16 (L2) in the direction shown in figure 7.

Starting from the next positive half-cycle, at time t ₅ , the thyristor switching cycle is repeated, providing a circular rotation of the stator field.

To ensure rotation of the magnetic flux vector of the stator field of a single-phase two-winding induction motor in accordance with the vector diagram shown in figure 4, in the sequence I-II-III-IV-V-VI, it is necessary to apply control pulses to the thyristors 1, 2, 3, 4 , 5, 6, 7, 8, 9, 10, 11, 12 (VS1-VS12) in the following order (Fig. 8):

- in the positive half-cycle, at time t ₁ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn on and work, providing I a fixed position of the stator magnetic flux when current flows through winding 14 (L1) in the direction shown in figure 8;

- in the negative half-period, at time t ₂ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn off, thyristors 1 (VS1), 8 (VS8), 12 (VS12) turn on and work, providing II a fixed position of the magnetic flux the stator when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 8;

- in the next positive half-cycle, at time t _{3 of} alternating voltage, thyristors 1 (VS1), 8 (VS8), 12 (VS12) turn off, thyristors 7 (VS7), 10 (VS10) turn on and work, providing III a fixed magnetic position the stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 8;

- in the next negative half-cycle, at time t _{4 of} alternating voltage, thyristors 7 (VS7), 10 (VS10) turn off, thyristors 5 (VS5), 4 (VS4) turn on and work, providing IV a fixed position of the stator magnetic flux during current flow winding 14 (L1) in the direction shown in figure 8;

- in the next positive half-cycle, at time t _{5 of} alternating voltage, thyristors 5 (VS5), 4 (VS4) turn off, thyristors 7 (VS7), 11 (VS11), 2 (VS2) turn on and work, providing V a fixed magnetic position the stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 8;

- in the next negative half-cycle, at time t ₆ , of an alternating voltage, thyristors 7 (VS7), 11 (VS11), 2 (VS2) turn off, thyristors 9 (VS9), 8 (VS8) turn on and work, providing VI a fixed magnetic position the stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 8.

Starting from the next positive half-cycle, at time t ₇ , the thyristor switching cycle is repeated, providing a circular rotation of the stator field.

To ensure rotation of the magnetic flux vector of the stator field of a single-phase two-winding induction motor in accordance with the vector diagram shown in figure 5, in the sequence I-II-III-IV-V-VI-VII-VIII, it is necessary to apply control pulses to the thyristors 1, 2 , 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (VS1-VS12) in the following order (Fig. 9):

- in the positive half-period, at time t ₁ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn on and work, providing I a fixed position of the stator magnetic flux when current flows through winding 14 (L1) in the direction shown in figure 9;

- in the negative half-period, at time t ₂ , of an alternating voltage, thyristors 3 (VS3), 6 (VS6) turn off, thyristors 1 (VS1), 8 (VS8), 12 (VS12) turn on and work, providing II a fixed position of the magnetic flux the stator when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 9;

- in the next positive half-cycle, at time t _{3 of} alternating voltage, thyristors 1 (VS1), 8 (VS8), 12 (VS12) turn off, thyristors 3 (VS3), 10 (VS10) turn on and work, providing III a fixed magnetic position the stator flow when current flows through the winding 16 (L2) in the direction shown in figure 9;

- in the next negative half-cycle, at time t ₄ , of an alternating voltage, thyristors 3 (VS3), 10 (VS10) turn off, thyristors 5 (VS5), 12 (VS12) turn on and work, providing IV a fixed position of the stator magnetic flux during current flow along the windings 14 (L1), 16 (L2) in the direction shown in figure 9;

- in the next positive half-cycle, at time t _{5 of} alternating voltage, thyristors 5 (VS5), 12 (VS12) turn off, thyristors 7 (VS7), 2 (VS2) turn on and work, providing V a fixed position of the stator magnetic flux during current flow winding 14 (L1) in the direction shown in figure 9;

- in the next negative half-cycle, at time t ₆ , of an alternating voltage, thyristors 7 (VS7), 2 (VS2) turn off, thyristors 5 (VS5), 9 (VS9), 4 (VS4) turn on and work, providing VI a fixed magnetic position the stator flow when current flows through the windings 14 (L1), 16 (L2) in the direction shown in figure 9;

- in the next positive half-cycle, at time t ₇ , of an alternating voltage, thyristors 5 (VS5), 9 (VS9), 4 (VS4) turn off, thyristors 11 (VS11), 2 (VS2) turn on and work, providing VII a fixed magnetic position the stator flow when current flows through the winding 16 (L2) in the direction shown in figure 9;

- in the next negative half-cycle, at time t ₈ , of an alternating voltage, thyristors 11 (VS11), 2 (VS2) turn off, thyristors 9 (VS9), 8 (VS8) turn on and work, providing VIII a fixed position of the stator magnetic flux when current flows along the windings 14 (L1), 16 (L2) in the direction shown in figure 9.

Starting from the next positive half-cycle, at time t ₉ , the thyristor switching cycle is repeated, providing a circular rotation of the stator field.

Thus, in accordance with the sequence of turning on the thyristors (Fig.2-5), you can reduce the speed of the motor in accordance with the formula:

,

,

;Where

;

ω is the rotation speed of the electric motor;

f _o - network frequency;

f _reg - adjusting frequency;

n is the number of half-periods involved in organizing a full 360 ° rotation of the stator's rotating magnetic field;

p is the number of pairs of poles.

Thus, the present invention can be used for vector-algorithmic regulation in a wide range of rotational speeds of a single-phase two-winding asynchronous electric motor when powered by AC voltage. At the same time, the thyristor switching control system is greatly simplified, which increases the reliability and efficiency of the entire installation and leads to the absence of the need to use a mechanical gearbox to reduce the speed of the electric motor.

Claims (1)

A semiconductor reducer driven by a network for controlling the speed of a single-phase two-winding asynchronous electric motor, comprising reversible semiconductor switches made on semiconductor switches implemented on four thyristors that are connected to the mains and stator windings of a single-phase two-winding asynchronous electric motor, characterized in that a single voltage alternating voltage is used and three reversible semiconductor switches, and in each switch the anode is not the thyristor and the cathode of the second thyristor are connected to zero the AC mains, and the anode of the third thyristor and the cathode of the fourth thyristor are connected to the phase of the AC mains, the middle common point of the first semiconductor switch connecting the cathode of the first thyristor to the anode of the second thyristor in this switch, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, it is connected to the combined first outputs of the stator windings of a single-phase double-winding asyn electric motor, the middle common point of the second semiconductor switch, connecting the cathode of the first thyristor to the anode of the second thyristor in this switch, and also connecting the cathode of the third thyristor and the anode of the fourth thyristor in this switch, is connected to the second output of the first stator winding of a single-phase two-winding asynchronous motor, the average common point of the third semiconductor switch connecting the cathode of the first thyristor in this switch with the anode of the second thyristor, as well as connecting The cathode of the third thyristor and the anode of the fourth thyristor that is connected in this switch are connected to the second output of the second stator winding of a single-phase two-winding asynchronous electric motor.

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