SU1365321A1 - D.c. electric drive - Google Patents

Abstract

The invention relates to electrical engineering and can be used. for controlling DC motors. The aim of the invention is to improve the quality of regulation. The actuator contains a filter 8 and a second diode 9, the anode of which is connected to the second output of the winding core of the electric motor 1 and the input of the filter 8. The output of the filter 8 is connected to the engine and the second output of the variable resistor 7. Anode of the thyristor 6 and the cathode of the second diode 9 are combined. The introduction of the second diode 9 and filter. 8 reduces the amplitude of self-oscillations and increases the stability of the auto-oscillation process. 1 il.

Description

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This invention relates to electrical engineering and can be used in direct current drives.

The aim of the invention is to improve the quality of regulation.

The drawing shows the scheme of the proposed electric drive.

The DC motor comprises an electric motor 1, a constant voltage source 2, a first diode 3, an inductor 4, a capacitor 5, a thyristor 6, a variable resistor 7, the first terminal of which is connected to the control electrode of the thyristor 6, the anode of which is connected to the first terminal inductance coil 4, and the cathode is connected to the first plate of the capacitor 5 and to the minus terminal of the source 2 of constant voltage J, the positive terminal of which is connected to the first terminal of the motor winding core

1 and the cathode of the first diode 3, the second terminals of the inductor 4 and the capacitor .5 are combined and connected to the anode of the first diode 3, the Electra drive also contains a low-pass filter 8 and a second diode 9, the anode connected to the second terminal of the electric motor 1. and the input of the low-frequency filter 8, the output of which is connected to the engine and the second output of the variable resistor 7, the common point to the negative terminal of the constant voltage source, the cathode of the second diode is connected to the anode of the thyristor 6,

The direct current drive operates as follows.

The self-oscillation cycle begins when the voltage on capacitor 5 is equal to the voltage of power supply 2 and the thyristor 6 opens. When the thyristor 6 is unlocked, the capacitor 5 overcharges. When the current through the thyristor 6 becomes zero, it closes, and the capacitor 5 now has opposite polarity, then the charge of the capacitor 5 from the source

2 nutrition. When the voltage on the capacitor 5 reaches the value of the voltage of the power source 2, the diode 3 is unlocked and the circuit including the winding of the electric motor 1, the diode 9, the coil 4 and the diode 2 flows through the circuit due to the magnetic energy stored in the inductance of this

653212

chains. When this current drops to zero, diodes 9 and 3 are locked by the action of emf. Next, the core brakes under the action of the moment of resistance on the shaft of the electric motor 1 until the thyristor 6 is turned on. When the current of the core flows, the rotational speed of the motor increases and the EMF of the core increases, while the voltage at the output of the low-frequency filter 8 decreases. If the filter time constant 8 is equal to the electromechanical

If the motor constant, the voltage at the output of the filter 8 is proportional to the voltage difference of the power supply source 2 and the EMF of the core 1, When the current of the core becomes equal to zero,

20, the EMF of the core 1 decreases and the voltage increases at the output of the filter 8. When a value is reached at which the control current becomes equal to the unlocking current, it turns on 25 seconds to thyristor 6 and then the self-oscillation cycle repeats. Since the switching on of the thyristor 6 occurs at the same value of the EMF and the same voltage at the output of the filter 8, set by the current of the thyristor unlocking and the set resistance value of the variable resistor 7, (which determines the rigidity of the mechanical characteristics of the detector | then with the growth of the moment switching frequency of the thyristor increases and at a certain value of the frequency the current of the core becomes continuous, a further increase in

40 load and frequency leads to an increase in the constant component of the current core and the disappearance of the interval in which diode 3 is turned on. This frequency is the maximum, which ensures reliable operation of the electric drive 3 and corresponds to the maximum load on the motor shaft.

An even greater increase in load

5Q and frequency leads to a decrease in the voltage to which it is charged. capacitor 5, which at a certain ypoBiie of this voltage leads to the breakdown of self-oscillations. Inductance

The gg of coil 4 must be much less than the inductance of the core of the electric motor 1, then during the recharge time the current of the core does not have time to change, which ensures stable locking

thyristor 6 at the end of the recharge and densator 4.

Claims (1)

Invention Formula A DC motor containing a motor, a DC voltage source, a first diode, an inductor, a capacitor, a thyristor, a variable resistor, the first terminal of which is connected to the control electrode of the thyristor, the anode of which is connected to the first terminal of the inductor, and the cathode is connected to the first plate of the capacitor and the negative terminal of the source of constant voltage, the positive output of which is 13653214 is connected to the first terminal of the motor winding and the cathode of the first diode, the second inductance and the second capacitor plate are combined and connected to the anode of the first diode, characterized in that, in order to improve the quality of regulation, a low filter is inserted into it frequency and the second diode, the anode of which is connected to the second output of the motor winding and the input of the low-frequency filter, the output of which is connected to the engine and the second output of the variable resistor, the cathode of the second diode is connected to the anode of the thyristor.