RU2485664C1 - Reversible one-phase bridge transistor converter - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: device contains two reversible switch solid-state blocks interconnected by common points connected to the beginning and ending of DC motor winding and equipped with two electronic switches in each block. Common connection point of two switches in the first block is connected to the phase of the AC supply mains and common connection point of two switches in the second block is connected to a zero conductor of the AC one-phase supply mains. Solid-state transistors with symmetrical structure are used as electronic switches. Emitters of solid-state transistors in the first block are joined and connected to the phase of the AC one-phase supply mains and emitters of solid-state transistors in the second block are joined and connected to a zero conductor of the AC one-phase supply mains. Common connection point of collectors of solid-state transistors in the first and second blocks is connected to the beginning of DC motor winding and the other common connection point of collectors of solid-state transistors in the first and second blocks is connected to the ending of DC motor winding.

EFFECT: reversible start-up and reverse operation of DC motor; extended capabilities of DC motor; reversible start-up and reverse operation of DC motor from one circuit of bridge converter that simplifies both main circuit and control circuit; prevention of potential short-circuiting; reduction of dimensions and costs, increase of the device reliability.

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Description

The present invention relates to a reversible semiconductor transistor rectifier devices and can be used in a controlled DC electric drive for power from a reversible bridge converter connected to a single-phase AC voltage supply network.

Known single-phase bridge diode converter for powering a DC motor, containing two semiconductor blocks connected by common points connected to the beginning and end of the armature winding of a DC motor, and equipped with two electronic keys in each block. As electronic keys used diodes. The common point of connection of the cathode and anode of the diodes of the first block is connected to the phase of the supply network of a single-phase alternating voltage. The common point of connection of the cathode and anode of the diodes of the second unit is connected to zero the supply network of a single-phase alternating voltage. One common point of combining the terminals of the cathodes of the diodes of the first and second blocks is connected to one terminal of the load or the beginning of the armature winding of the DC motor. Another common point of combining the terminals of the anodes of the diodes of the first and second blocks is connected to another terminal of the load or to the end of the armature winding of the DC motor (Nemtsov M.V., Nemtsova M.L. Electrical Engineering and Electronics / M.V. Nemtsov, M.L. Nemtsova . - Academy, 2007. - P.338, Fig. 14.6).

The disadvantages of this device are the lack of the ability to control the speed of the DC motor, the inability to reverse, which requires another bridge circuit, as well as low profitability and reliability due to the large number of elements.

The closest to the proposed invention in terms of technical nature and the achieved result (prototype) is a thyristor bridge converter, i.e. a single-phase bridge circuit containing two reversing key semiconductor blocks connected by common points connected to the beginning and end of the armature winding of a DC motor, and equipped with two electronic keys in each block. Each unit is connected to a single-phase AC voltage supply network. Thyristors are used as electronic keys. The common point of connection of the terminals of the cathode and anode of the two thyristors in the first block is connected to the phase of the AC mains. The common point of connection of the terminals of the cathode and anode of the two thyristors in the second block is connected to zero the AC mains. The common point of connection of the terminals of the thyristor cathodes of the first and second blocks is connected to one load terminal or the beginning of the armature winding of the DC motor, and the common point of the connection of the terminals of the thyristor anodes of the first and second blocks is connected to another load terminal or end of the armature winding of the DC motor. At the same time, a second single-phase bridge circuit is required for reversing (G. Zinoviev, Fundamentals of Power Electronics. / G.S. Zinoviev. - NSTU, 2001. - P.66, Fig. 2.2.3a).

The main disadvantages of the described thyristor bridge converter are the impossibility of reversing the start and operation of the DC motor in the opposite direction, which leads to a reduction in functionality, to the need to use another single-phase bridge circuit to reverse, which leads to an increase in the number of thyristors and fuzzy control of bridges of different polarity , namely, with the untimely shutdown of one bridge and the inclusion of another technological short circuit between Do bridges, to the complexity of the control system, as well as to increase the dimensions of the device, low efficiency and reliability due to the large number of elements.

The present invention solves the problem of reversing the start and operation of the DC motor in the opposite direction, expanding the functionality of the DC motor, realizing the reverse start and operation of the DC motor from one circuit of the bridge converter, which simplifies both the power circuit and the control system, eliminates the possibility of technological short circuit, and also reduces the size and cost, increases reliability.

To solve the problem in a reversible single-phase bridge transistor converter, containing two reversing key semiconductor blocks, interconnected by common points connected to the beginning and end of the armature winding of a DC motor, and equipped with two electronic keys in each block, and the common point of connection of two keys in the first block is connected to the phase of the supply network of a single-phase alternating voltage, and the common point of connection of two keys in the second block is connected to zero supply with five-phase AC voltage, according to the invention as electronic keys used semiconductor transistors symmetric structure, the emitters of semiconductor transistors of the first block are connected and are connected to phase supply single-phase AC voltage, and an emitter semiconductor transistors of the second unit are connected and are connected to the zero-phase mains alternating voltage network. One common point for combining the collectors of semiconductor transistors of the first and second blocks is connected to the beginning of the armature winding of the DC motor, and another common point for combining the collectors of semiconductor transistors of the first and second blocks is connected to the end of the armature winding of the DC motor.

The reverse start-up and operation of the DC motor in the opposite direction is achieved by using the transistor due to its symmetrical structure (p-n-p, n-p-n) to pass current in the forward and reverse directions in the key mode.

The expansion of the functionality of the DC motor due to the fact that the use of a reversible single-phase bridge transistor converter determines the implementation of not only the regulation of the rotational speed of the DC motor shaft, but also the reverse.

Simplification of the power circuit and control system, eliminating the possibility of technological short circuits are achieved through the use of a single bridge reversible transistor converter for reversing.

The reduction in size, improving the efficiency and reliability of the device is ensured by eliminating the use of a second thyristor bridge converter while reducing the number of elements of the device.

The invention is illustrated in the drawing, where Fig. 1 shows a circuit diagram of a reversible single-phase bridge transistor converter when currents flow that provide the DC motor shaft to move in the forward direction; figure 2 is a circuit diagram of a reversible single-phase bridge transistor converter in the direction of the currents, ensuring the movement of the DC motor shaft in the "back" direction; figure 3 is a timing diagram of the operation of pairs of transistors in a reversible bridge transistor converter with the direction "forward" and the opening of pairs of transistors throughout the half-period of the rectified voltage; figure 4 is a timing diagram of the operation of pairs of transistors in a reversible bridge transistor converter in the forward direction and partial opening of transistor pairs during each half-period of the rectified voltage; figure 5 is a timing diagram of the operation of pairs of transistors in a reversible bridge transistor converter when the direction is "back" and the opening of pairs of transistors throughout the half-period of the rectified voltage; figure 6 is a timing diagram of the operation of pairs of transistors in a reversible bridge transistor converter with the direction "back" and the partial opening of the pairs of transistors during each half-period of the rectified voltage.

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

- Uc - source of alternating voltage;

- U _dv - voltage on the engine;

- f - phase;

- O is zero;

-t - current time;

- I _dv - current flowing through the motor;

- VT1-VT4 - transistors;

- C1 and C2 - ends of the armature winding of a DC motor;

- solid arrows - the direction of current flow into the positive half-periods of the supply alternating voltage;

- dashed arrows - the direction of current flow into the negative half-periods of the supply alternating voltage;

- dash-dotted arrows - schematic borders of reversing key semiconductor blocks.

The reversible single-phase bridge transistor converter contains reversing key semiconductor blocks 1 and 2, equipped with two electronic keys in each block. As electronic keys, semiconductor transistors of a symmetric structure (p-n-p or n-p-n) are used. So, the semiconductor block 1 contains transistors 3 (VT1) and 4 (VT2), and the semiconductor block 2 contains 5 (VT3) and 6 (VT4).

The collector of the transistor 3 (VT1) of the semiconductor block 1 is connected to the collector of the transistor 5 (VT3) of the semiconductor block 2, and their common point of association is connected to the beginning 7 (C1) of the armature winding of the DC motor. The collector of the transistor 4 (VT2) of the semiconductor block 1 is connected to the collector of the transistor 6 (VT4) of the semiconductor block 2, and their common point of association is connected to the end 8 (C2) of the armature winding of the DC motor. Thus, blocks 1 and 2 are connected by common points connected to the beginning 7 (C1) and the end 8 (C2) of the anchor winding of the DC motor.

In the semiconductor unit 1, the emitter of transistor 3 (VT1) is connected to the emitter of transistor 4 (VT2), and their common connection point is connected to the phase of the supply network of a single-phase alternating voltage. In the semiconductor unit 2, the emitter of the transistor 6 (VT4) is connected to the emitter of the transistor 5 (VT3), and their common connection point is connected to zero the supply network of a single-phase alternating voltage (Fig. 1, Fig. 2).

Using a reversible single-phase bridge transistor converter, it is possible to control the rotation speed of the DC motor shaft by partially opening the transistors, as well as reversing the rotation of the DC motor by using the possibility of the transistor due to its symmetrical structure (pnp, npn) to pass current as in forward and backward in key mode.

To rotate the DC motor shaft in the forward direction, it is necessary to apply control pulses to the transistors in accordance with the diagram shown in FIG. 3.

In the positive half-cycle, at time t1 of the alternating voltage, transistors 3 (VT1) and 6 (VT4) turn on and work.

In the negative half-period, at time t2 of alternating voltage, transistors 3 (VT1) and 6 (VT4) are turned off, transistors 5 (VT3) and 4 (VT2) turn on and work.

In the next positive half-cycle, at time t3 of the alternating voltage, transistors 5 (VT3) and 4 (VT2) are turned off, transistors 3 (VT1) and 6 (VT4) turn on and work.

Starting at time t3, the switching cycle of the transistors is repeated, providing rotation of the DC motor shaft in the forward direction.

The regulation of the rotational speed of the DC motor with the direction of rotation of the shaft "forward" is achieved by the incomplete opening of the pairs of transistors during the entire half-cycle according to Fig.4.

In the positive half-cycle, at time t1 of alternating voltage, transistors 3 (VT1) and 6 (VT4) turn on and work, at time t2, transistors 3 (VT1) and 6 (VT4) are turned off.

In the negative half-period, at time t3 of alternating voltage, transistors 5 (VT3) and 4 (VT2) turn on and work, at time t4, transistors 5 (VT3) and 4 (VT2) are turned off.

Starting from the next positive half-cycle, at time t5, the transistor switching cycle is repeated, providing rotation of the DC motor shaft.

This switching circuit and the control sequence of transistors (Fig.3, Fig.4) allows you to adjust the speed of rotation of the DC motor shaft during rotation "forward".

To implement the rotation of the DC motor shaft in the "back" direction, it is necessary to apply control pulses to the transistors in accordance with the diagram shown in Fig.5.

In the positive half-cycle, at time t1 of the alternating voltage, transistors 4 (VT2) and 5 (VT3) turn on and work.

In the negative half-period, at time t2 of the alternating voltage, transistors 4 (VT2) and 5 (VT3) are turned off, transistors 6 (VT4) and 3 (VT1) are turned on and work.

In the next positive half-cycle, at time t3 of the alternating voltage, transistors 6 (VT4) and 3 (VT1) are turned off and transistors 4 (VT2) and 5 (VT3) turn on and work.

Starting at time t3, the turn-on cycle of the transistors is repeated, providing rotation of the DC motor shaft.

The regulation of the rotational speed of the DC motor shaft with the direction of rotation of the shaft "back" is achieved by incomplete opening of the pairs of transistors during the entire half-cycle, according to Fig.6.

In the positive half-cycle, at time t1 of alternating voltage, transistors 4 (VT2) and 5 (VT3) turn on and work, at time t2, transistors 4 (VT2) and 5 (VT3) are turned off.

In the negative half-period, at time t3 of alternating voltage, transistors 6 (VT4) and 3 (VT1) turn on and work, at time t4, transistors 6 (VT4) and 3 (VT1) are turned off.

Starting from the next positive half-cycle, at time t5, the transistor switching cycle is repeated, providing rotation of the DC motor shaft.

This switching circuit and the control sequence of transistors (Fig.5, Fig.6) allows you to adjust the speed of rotation of the DC motor shaft in the direction of "back".

Thus, based on the foregoing, it can be seen that the present invention has advantages over the known thyristor bridge converter due to the possibility of a stable reverse with an equivalent value of efficiency in both directions and the operation of the device in both forward and reverse directions, increased reliability, efficiency and reduced dimensions by reducing the number of power elements.

Claims (1)

A reversible single-phase bridge transistor converter containing two reversing key semiconductor blocks, connected by common points connected to the beginning and end of the armature winding of a DC motor, and equipped with two electronic keys in each block, and the common connection point of two keys in the first block is connected to phase of the supply network of a single-phase alternating voltage, and the common point of connection of two keys in the second block is connected to zero the supply network of a single-phase alternating voltage characterized in that the semiconductor transistors of a symmetric structure are used as electronic keys, the emitters of the semiconductor transistors of the first block are connected and connected to the phase of the supply network of a single-phase alternating voltage, and the emitters of semiconductor transistors of the second block are connected and connected to zero of the single-phase alternating voltage supply, one the common point of the union of the collectors of semiconductor transistors of the first and second blocks is connected to the beginning of the armature winding of the motor a DC coupler, and another common point for combining the collectors of semiconductor transistors of the first and second blocks is connected to the end of the armature winding of the DC motor.

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