RU2557805C1 - Pulse inductive dynamic drive - Google Patents

Abstract

FIELD: motors and pumps.

SUBSTANCE: invention relates to inductive dynamic drives used for the creation of pulse actions of required values and durations, in particular for non-explosive sources of seismic waves. A pulse inductive dynamic drive contains an inductive dynamic engine, to the excitation winding of which through an operated key a capacitive storage with a charger is connected. A series connected diode and resistor are connected to leads of the engine winding, in parallel to which a capacitor is connected.

EFFECT: reduction in thermal losses and heating of the excitement winding of the inductive dynamic engine and reduction of duration of the back front of the force created by the engine.

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Description

The invention relates to induction-dynamic drives used to create pulsed effects of the required size and duration in technological devices for general industrial use, for example, in electrical apparatuses, during stamping and molding of parts, pressing, and also in pulse seismic sources in which the induction-dynamic drive provides a pulse impact on soil or water in order to form seismic waves in them.

Known accepted as an analog induction-dynamic drive [L.N. Karpenko "High-speed electrodynamic tripping devices." (Energia Publishing House, Leningrad Branch, 1973, pp. 8-9, Fig. 156)], which contains a capacitive energy storage device equipped with a charger, a controlled key for discharging the storage device to the motor excitation winding, and a diode connected in parallel to the motor winding . This device works as follows: a capacitive storage pre-charged from a charger through a key is discharged to the motor excitation winding. When the current passes through the field winding, the motor creates an electromagnetic force, the value of which is proportional to the quadratic value of the current. At the time of the full discharge of the capacitive storage, the voltage on the diode changes sign, it opens and the current flowing through the motor winding closes through the diode. In this case, the key is turned off and the capacitive storage is de-energized, which ensures a decrease in the required power of the charger during the next subsequent charge of the capacitive storage.

The disadvantages of the analogue include significant heat in the winding when it flows through it from the moment the diode turns on an exponentially decreasing current, which leads to its additional heating. The analog drive does not provide the ability to quickly change the duration of the generated mechanical impulse. These shortcomings reduce the technical characteristics of the drive and limit its application.

Known adopted for the prototype technical solution of the induction-dynamic drive [Invention RU 2485614 C2, publ. 06/20/2013], which, like the analogue, contains a capacitive energy storage device with a charger, a controllable key for discharging the capacitance to the field winding of the motor, and a diode connected to the terminals of the winding. Unlike the analog, the capacitive storage is made of the main capacity and additional capacity connected to it through the diode. This solution allows you to expand the peak of the current in the field winding and, accordingly, increase the mechanical impulse created by the drive applied to the process load by the motor armature.

However, as in the analogue, during the period of time when the winding current flows through a diode connected to its terminals, a significant portion of the winding magnetic field that is not converted into mechanical energy is released in the form of heat in the winding. In addition, the current flowing through the winding and the diode is characterized by a significant, several times greater than the duration of the discharge of the capacitive storage to the winding constant time. As a result, after the force is generated during the discharge time of the capacitive storage, the drive creates a significant exponentially decreasing force.

These shortcomings reduce the technical characteristics of the drive and limit the possibility of its application.

The objective of the invention is to improve the technical characteristics of a pulse induction-dynamic drive and expand the scope of its application.

The technical result consists in reducing heat losses and heating the field winding of the induction-dynamic motor and reducing the duration of the trailing edge of the force generated by the motor.

The proposed pulsed induction-dynamic drive contains a capacitive energy storage device with a charger, an induction-dynamic motor with an excitation winding and a controlled key for discharging a capacitive storage device to the excitation winding. A series-connected diode and a resistor with a capacitor connected in parallel to it are connected to the winding conclusions.

The technical result is achieved due to the fact that between the terminals of the field winding are connected series-connected diode and resistor, in parallel to which a capacitor is connected.

Figure 1 shows the electrical circuit of the proposed drive, and figure 2 is a graph of the voltage on the field winding of the motor, the current of the field winding and the force generated by the motor.

The pulse drive contains a capacitive energy storage device 1 with a charger 2. A controlled key 3 is included in the discharge circuit of the capacitive storage device on the excitation winding 4 of the motor, which is placed in the groove of the inductor 5 of the induction-dynamic motor, and the motor armature is made in the form of plates adjacent to the plane of the winding 4 6 made of high conductivity material. To the conclusions of the winding 4 through the diode 7 is connected a resistor 8, in parallel with which a capacitor 9 is connected.

The drive operates as follows. Before starting work, the capacitive storage device 1 (Fig. 1) is charged from the charger 2 to the required voltage. When you open at the time t ₀ (Fig. 2) from the control system (not shown in Fig. 1) the controlled key 3, the drive _{1 is} discharged to the excitation winding 4 of the motor for a time t ₁ , which leads to the application of a voltage pulse 10 to the winding, flowing along winding a current pulse 11 (FIG. 2) and creating a magnetic flux 12 around the winding (FIG. 1). Due to the shielding of the magnetic flux by the conductive plate 6 of the armature, the flux passes through the region where the armature fits to the winding, and an electrodynamic force 13 repelling them is created between the armature and the armature (FIGS. 1 and 2).

where i (t) is the current 11 of the field winding;

L _e - the equivalent value of the inductance of the winding, depending on the gap between the winding and the plate and the coefficient of magnetic coupling between them.

Force 13 has a quadratic dependence on the current in the winding. Due to the influence of the active resistance 14 of the winding, the current 11 and, accordingly, the force 13 reach a maximum value somewhat earlier than the time t _{1 of the} change in sign of voltage 10 on the winding 4.

From the moment t _{1 of} turning on the diode 7 and, accordingly, turning off the controlled switch 3, the current 11 of the winding passes through the diode 7 and the resistor 8 and decreases according to an exponential law with a time constant τ.

where I ₁ is the current in the winding at time t ₁ , a

, где r₁ - сопротивление обмотки 4, а r₂ - добавочного резистора 8.In (3) L _E - inductance coil, which value can be assumed constant, and

where r ₁ is the resistance of the winding 4, and r ₂ is an additional resistor 8.

The losses A _r in the winding and resistor are proportional to the quadratic value of the current:

In view of (3)

and, therefore, the losses A _r are independent of the value of the additional resistance r ₂ and are equal to the energy of the magnetic field of the motor winding with inductance L _E at current I ₁ at time t ₁ .

Их относительные значенияDue to the inclusion of a resistor 8 with resistance r _{2 in} series with diode 7, the total losses A _r are divided into losses A _r1 in the resistance r _{1 of the} winding and losses A _r2 in the resistor 8, depending on the value

Their relative values

в обмотке уменьшаются до 1/3, а при n=4 - до 1/5 от потерь A_r, выделяемых в обмотке при n=0 (r₂=0).In real technical solutions, the resistance value r ₂ can be 2-4 or more times higher than the value r ₁ , i.e. n≈2 ÷ 4. For n = 2 losses

in the winding are reduced to 1/3, and for n = 4 - to 1/5 of the losses A _r allocated in the winding at n = 0 (r ₂ = 0).

The force P developed by the motor is proportional to the quadratic value of the current and can be written as

those. force P varies with time constant

Figure 2 for comparison shows the force 13 developed by the engine from time t ₁ at values n = 0 and n = 2. Compared with the case n = 0 at n = 2, the trailing edge of the generated force 13 is characterized by a faster decrease in force, with a time constant τ / 6.

With increasing n, the mechanical impulse N created from time t ₁ decreases between the inductor 5 with the winding 4 and the armature of the motor 6. Its value N is proportional to the integral value of the generated force and decreases with increasing τ.

The relative value of the mechanical impulse, characterized by the ratio of its values at n ≠ 0 and n = 0:

в обмотке возбуждения двигателя.which is similar to relation (6) for determining the relative value of losses

in the field winding of the motor.

Managed key 3 can be performed using one or more series-parallel connected (depending on drive power) single-operation or two-operation (turn off) thyristors. The use of a capacitor 9 connected in parallel to an additional resistance 8 reduces the switching losses in the thyristors and increases the reliability of their operation.

Thus, the proposed technical solution of a pulsed induction-dynamic drive ensures the achievement of the task by reducing heat loss in the excitation winding of the drive motor and decreasing the force generated by the engine after the controlled key is turned off.

Claims (1)

A pulse induction-dynamic drive containing an induction-dynamic motor, to the excitation winding of which a capacitive storage device with a charger is connected via a controlled key, characterized in that a series-connected diode and a resistor are connected to the winding leads, in parallel with which a capacitor is connected.

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