SU586534A1 - Dc electric drive - Google Patents

Description

(54) DC ELECTRIC DRIVE

In addition, due to overshooting, the drive operation will be characterized by insufficient reliability. The overshoot speed is due to the fact that the reverse flow of the engine will start at an engine speed close to the specified rotational speed. Due to the inertia of the excitation circuit to a change in the direction of flow, and consequently, the engine torque, a certain time is required. During this time, the engine speed continues to increase under the action of the active load torque, and it will exceed the specified rotational speed. Due to speed overshoot, the transient time increases. The overshoot of the speed also reduces the reliability of the drive, since it can lead to accidents in the mechanical part of the drive and cause a so-called “inverter breakthrough” due to an increase in voltage on the motor.

The aim of the invention is to reduce the overshoot speed and the adjustment time when the engine is running with the load moment active. To achieve this goal, the DC motor is provided with an additional speed controller and a non-linear element having a gain factor for one of the input signal polarities less than the other, with the first input of the additional speed controller connected to the speed reference signal source through a non-linear element, the second input is to the speed sensor, and the output is to the input of the block for setting the excitation current.

FIG. 1 shows a functional diagram of the proposed electric drive; in fig. 2 is a diagram of the change of its basic coordinates when the engine speed is reversed in the direction coinciding with the action of the active load moment.

The electric drive contains the DC motor 1 and its excitation winding 2, the non-reversing converter of the core 3 and the reversing converter 4 of the excitation circuit, the regulator 5 of the core, the regulator 6 of the excitation current, the main regulator 7 of speed, the additional regulator 8 of speed, a module 9 allocation unit, a key element 10, an AND control unit, a field current reference unit 12, a nonlinear element 13, a speed sensor 14. A key element 10 and a control device 11 form a logic device for blocking the current and cor. The input of the speed reference signal 15 is connected to the input of the controller 8.

The choice of non-linear element is determined as follows.

The gain of the nonlinear element for one of the polarities of the input signal should be less than for the other. A higher gain factor or, equivalently, a higher speed setpoint for the additional speed controller, corresponds to the drive operating in the direction opposite to the active torque on the IpyjKH.

Offered electric pad. as follows.

5 When reversing at the time point i of the source cnrna.ia set the speed at its input, the polarity of the t / pci and 6pc2 voltages changes at the outputs of the main 7 and additional 8 speed regulators, respectively. A change in the voltage field t / pc2 causes, in turn, a change in the direction of the setpoint value of the motor flux at the input of the excitation current command block 12, as a result of which the reverse of the flux F of the motor starts at the same time / 1. In the period ti / 2, the logical device for blocking the current of the cor reduces the current of the corr IH to zero, since the current direction of the motor flow, controlled by the control device 11, does not correspond to the required direction of its moment, which is determined by the polarity of the voltage 6pc1 the main speed controller 7 and is controlled by the key element 10; At this time, the reduction in engine speed occurs under the action of a moment of static load. From the moment of time tz flow. Acquires the desired direction, the logical device stops blocking

0 current core, and since that time the speed reduction and its reverse occur already under the action of the total torque of the engine and the moment of static load. Due to the fact that in the direction of the reverse, the additional speed controller 8 has a lower setpoint than the main 7, the polarity of the voltage Upc2 at its output changes when the engine speed 2 2 is less than the speed and at which the voltage polarity changes f / pci

0 at the output of the main controller. In time, the engine torque decreases from maximum value to zero due to a decrease in engine flow. From time t logical device 11.lp

5 blocking the current of the core again reduces the current of the core to zero, since the direction of flow of the engine no longer corresponds to the required direction of its moment, and further the speed of the engine increases due to the effect of the active moment created by the load. At time t, when the motor accelerates to a speed of the seam close to the steady speed Shust, the polarity of the voltage fypci at the output of the main speed controller changes, and the logic device stops blocking the current of the core. By this time, the engine's flow is already growing enough to a sufficient size in the required direction, and therefore the engine is capable of

0 to develop a moment sufficient to balance the moment created by the load. All; 1 the consequence of this transition to the steady speed of rotation of the platform is smoothly, the oc-i overshoot the speed and with a small transition time of the process.

Thus, the invention makes it possible with simple means to eliminate the overshoot}, the use of engine speed, shorten the transient process and increase the reliability of the electric drive.

Claims (2)

1. Express information “Automated electric drive, electrical technologies and power supply of industrial enterprises, M., 1974, No. 44, ref. 214. p. 14-21. 2. Express information “Automated electric drive, electrical technologies and power supply of industrial enterprises, M., 1974, No. 9, ref. 50, s. 26-29. (Y-, ts Shust ; t