SU1606279A1 - Apparatus for controlling electric drive for feeding electrode wire - Google Patents

Abstract

The invention relates to electrical engineering, namely to electric drives of mechanized hand tools, and can be used in welding engineering, in electric drives for feeding electrode and filler materials. The purpose of the invention is to improve the quality of the welded joint by increasing the accuracy and speed in controlling the output parameters of the motor for the material feed drive. The device comprises a motor electric parameter sensor connected in series, a matching device, an adder, an integrator, a logic unit, a driver for the control signal and a power converter. The monitoring of the measured parameter of the electric motor is carried out in each step of the power converter operation with the change of this parameter according to the functional law necessary in the given drive. 2 Il.

Description

The invention relates to welding, in particular, to electric drive control devices for supplying electrode and filler material, and can be used in drives of moving mechanisms, in mechanized hand tools, as well as in drives for other purposes.

The aim of the invention is to improve the quality of the welded joint by increasing the accuracy and speed of the electric drive of the supply of electrode or filler material.

Figure 1 presents the block diagram of the proposed device; FIG. 2 is an example of a flowchart of a logic block.

The control unit contains (1) an electrical parameter sensor 1 interconnected in series, connected to the core winding of the electric motor 2, matching device 3, adder 4. integrator 5, logic unit 6 and driver 7 of the control signal, as well as unit 8 of the speed , the output of which is connected to the input of the adder 4, the power converter 9, the input of which is connected to the output of the former 7 and the synchronization unit 10 connected by the output to the synchronizing input of the integrator 5. The synchronization unit 10, in depending on the type of power converter 9 and the type of electricity supplied to it, may have

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your sync input. For example, when using a controlled rectifier powered by an alternating voltage as the power converter 9, the synchronization unit 10 must be synchronized with it. In this case, its input is connected to a source of electrical energy. When constructing a power converter 9 on the basis of a frequency-pulse converter powered by a constant voltage, the synchronization unit 10 must be connected to the output of the driver 7 of the control signal. In the case of using a pulse-width converter, with the same type of power supply, the synchronization unit 10 must realize the complete synchronization of the operation of the device and the inputs may not have.

Logic block 6 may contain (FIG. 2) a functional converter 11, the input of which is the input of the unit, and the output connected to the first input of the comparator 12, to the second input of which the output of the reference voltage source 13 is connected. The output of comparator 12 is the output of block 6.

In order to obtain the output characteristic of the simplest type of drive (stabilization of the speed or torque on the motor shaft), the functional converter must perform a linear transformation. In this case, its functions can be transferred to other elements of the device (for example, matching device 3 or integrator 5 as a constant integration coefficient), and it itself is excluded from the logic block 6.

The device works as follows.

When a control signal is applied to the control input of the power converter 9, a voltage pulse is applied to the main winding of the electric motor 2, the duration of which is determined by the moment the control signal is applied and the moment of the end of the current device operation cycle. Under the action of the current flowing in the core winding, the measles of the electric motor 2 begins to rotate. At the end of the current clock cycle, and, accordingly, at the end of the voltage pulse from the power converter 9 to the main winding of the electric motor 2, its measles continues to rotate by inertia. The current in the root winding does not decrease immediately, due to the inductive nature of its resistance. The time during which the current decreases to zero increases with increasing load on the motor shaft. Integral value of the current-i of the core winding in the time interval from the beginning of the cycle to the achievement of K1 with the current value of zero

directly proportional to the magnitude of the load on the motor shaft. From the sensor 1, the instantaneous value of the current of the crust winding through the matching device 3 is continuously fed to the input of the adder 4. At the second

0 the input of the adder 4 receives a signal from the setpoint 8, whose detection determines the number of revolutions of the engine shaft with the minimum load values at the last. The total signal arrives at the information

5 integrator input 5, from the beginning of the next clock cycle, i.e. after the expiration of the pulse reset, coming to the sync input of the sum signal from the output of the adder 4, With the minimum load on the motor shaft 2 current values of the core winding in the integration interval are close to zero and therefore the rate of increase of the signal at the output of the integrator 5 is determined by the signal from the output of the setpoint 8. With an increase in the load on the shaft of the electric motor 2, the instantaneous values of the core winding in the integration interval increase and, therefore, the growth rate increases no signal

0 at the output of the integrator 5, which is fed to the input of the logic unit 6. Logic unit 6 processes the incoming information taking into account the real time scale, as a result of which

5, the moment of application of the control signal to the power converter 9 is determined taking into account the formation of the required output characteristic of the electric drive. Information about the moment of supplying the control signal is fed to the input of the driver 7 of the control signal, where it is converted into a signal with the parameters necessary to control the key elements of the power converter 9. In the logic unit 6

5, to determine the moment of supplying the control signal, a comparator 12 (FIG. 2) can be used, one of the inputs of which receives a reference Signal from the source 13 of the reference voltage. The second input of the comparator 12 receives a signal from the output of the integrator 5, converted by a predetermined relationship in the functional converter 11. The moment when both input signals reach

5, the comparator 12 has the same value and is the moment the control signal is applied. The type of functional relationship by which the signals are converted in the functional converter 11 is determined based on the specific load characteristics of the electric motor, the intrinsic external characteristics of the power converter and the required form of the output characteristic of the electric drive.

The proposed device makes it possible to achieve an increase in the quality of the welded joint, since the accuracy and speed of the drive of the supply of electrode or filler material reduces the number of defects (the flaking decreases, the stability of the seam shape increases, and the metal loss for spatter decreases).

Claims (1)

The invention The device for controlling the electric drive of the electrode wire, containing an electric motor with a sensor of its electrical parameter, 0 five 0 a power converter, an integrator, a logic unit, a rotational speed adjuster and a synchronization unit, characterized in that, in order to improve the quality of welding by increasing the accuracy and speed of the electric drive, a matching device, an adder and a driver of the control signal are inserted into it, while the sensor output electrical parameter is connected via a matching device. The first input of the adder, the second input of which is connected to the output of the speed setting knob, the output of the adder is connected to the information input of the integrator, the synchronization input of which is connected to the synchronization unit, the output of the integrator is connected to the control input of the power converter via a logic block and driver.