RU160467U1 - ELECTROMAGNETIC DRIVE WINDING CURRENT CONTROL DEVICE WITH ANCHOR RETURNING AND ACCESSIBLE MOVEMENT - Google Patents

Abstract

A current control device for the windings of an electromagnetic drive with a reciprocating movement of the armature, containing two chains of a transistor switch, a current sensor and a reverse diode for each of the two windings, characterized in that negative feedback on the difference of currents in the windings is introduced through the differential amplifier, the output of which is connected to the inverting input of the comparator, and the inputs to current sensors, the second transistor switch being controlled by the comparator through the inverter, and the reverse diodes are switched on parallel to the windings connected in series with current sensors.

Description

The proposed utility model relates to electrical engineering, in particular to direct current electromagnetic drives (DC) with controlled reciprocating movement of the working body and can be used to create electromagnetic forces directed in opposite directions, for example, in devices such as spool valves or electromagnetic bearings.

To control the magnitude of the current of the winding of power electromagnetic converters (EMFs), a number of different electronic devices are known, for example, US patents 4381532, 4556926, 4764840, 4949215 and 5345181. A common characteristic feature in these devices is the use of a transistor connected in series with the winding, a voltage source and current sensor (resistor). To protect the transistor against overvoltage, a reverse diode is connected in parallel with the winding. The voltage across the sensor resistor indicates how much current flows through the EMF coil. Differences in transistor control devices are due to differences in control objectives. Usually it is necessary to control the current through the winding so that this current does not exceed the set value, otherwise the solenoid will fail. To control the EMF force in the EM, a control device is required that provides, if not stabilization of the force at the armature, then at least stabilization of the current in the winding.

Also known is a current control device for windings of an electromagnetic drive with reciprocating armature (US Pat. No. 4,546,403 (Switching driver with solenoid current proportional to an analog voltage "), which is a prototype of the proposed utility model. It contains a series-connected power source (battery), a transistor switch, a winding and a current sensor (resistor). To control the transistor switch, there is a hysteresis comparator and a single-shot that forms the duration of the off state of the switch. The voltage from the current sensor is applied to and the comparator’s inverting input. The reference voltage is applied to the comparator non-inverting input. A closed key leads to an increase in the current in the winding. When the voltage at the current sensor exceeds the reference voltage, the signal at the comparator output switches the transistor switch to the closed state and starts the one-shot. The current in the winding starts to decrease, flowing through the reverse diode. Closing the transistor switch will occur after the operation of a single-shot.

The disadvantage of this device is the limited functionality of providing a pulse mode with stabilization of the average current value in the winding of only one EMF. For EF, two EMFs must be used. The application of the above circuitry to power two-winding electric motors with two windings is unacceptable due to the fact that when moving the armature there is a different change in the inductances of the windings, and, consequently, the rate of increase and decrease of currents and, accordingly, the pulse rate of current pulses and electromagnetic forces. This causes beats in the resulting electromagnetic force with a constant control signal. It is also significant that the efforts in the electric field are determined not by the absolute values of the currents in the windings, but by their difference.

The objective (technical result) of the proposed utility model is to expand the functionality of the current control device of the windings of an electromagnetic drive with reciprocating arm movement, as well as the elimination of beats in the electromagnetic forces created by them with a constant control voltage.

The task is achieved in that in the known device for controlling the currents of the windings of an electromagnetic drive with reciprocating armature containing two chains of a transistor switch, a current sensor and a reverse diode for each of the two windings, negative feedback on the difference of the currents in the windings through a differential amplifier the output of which is connected to the inverting input of the comparator, and the inputs to current sensors, the second transistor switch being controlled by the comparator through the inverter, and the inverse These diodes are connected in parallel with the windings connected in series with current sensors.

The drawing shows a functional diagram of a device for controlling the currents of the windings of an electromagnetic drive.

The proposed device contains: 1, 2 - windings; 3, 4 - current sensors; 5, 6 - transistor switches; 7, 8 - reverse diodes; 9 - differential amplifier; 10 - a comparator; 11 - inverter.

The device operates as follows. The logical signal from the output of the comparator 10 is transmitted to the transistor switch 6, which, when closed, provides an increase in the signal at the output of the amplifier 9 and the inverting input of the comparator 10. The inverter 11 provides alternating closure of the transistor switches 5, 6. Both currents in the windings 1, 2 and their difference, have a sawtooth shape. At the same time, a sawtooth signal proportional to the difference in currents is provided at the output of amplifier 9. The upper point of this signal is determined by the sum of the control signal U _y and the hysteresis of the comparator 10, and the lower - by their difference. Thus, the stabilization of the average value of the difference of the currents in the windings at the level of U _{y is} ensured. The magnitude of the hysteresis is determined by the ripple of the current difference necessary for the excitation of the armature vibration in the electric field. The elements of the device operate at the same frequency, which, in accordance with the provisions of the theory of oscillations, eliminates the possibility of beats.

Thus, the technical result is:

- expanding the functionality of the electromagnetic drive when performing it not only with one, but also with two EMFs, the creation of which is necessary to ensure controlled movement of the working body;

- the exclusion of beats in the force applied to the working body of a controlled electromagnetic drive, which improves the quality of its movement by stabilizing the average current difference in proportion to the control voltage and reduces the cost of control.

Claims (1)

A current control device for the windings of an electromagnetic drive with a reciprocating movement of the armature, containing two chains of a transistor switch, a current sensor and a reverse diode for each of the two windings, characterized in that negative feedback on the difference of currents in the windings is introduced through the differential amplifier, the output of which is connected to the inverting input of the comparator, and the inputs to current sensors, the second transistor switch being controlled by the comparator through the inverter, and the reverse diodes are switched on parallel to the windings connected in series with current sensors.

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