SU860247A2 - Device for regulating electric motor anchor current - Google Patents

Description

(54) DEVICE FOR REGULATING ANCHOR CURRENT

one

The invention is fireproof to control devices of direct current electric drives and can be used in high-speed electric pilots with optimal control, in which the duration of electromagnetic and electromechanical transients plays a decisive role.

According to the main author. St. N 656169 a device is known for controlling the current of a motor core, comprising an adjustable valve converter, a current regulator of the core and a current sensor of the core, a reference aperiodic link with feedback on switching and dynamic parameters and a control element connected between the output and input of the current regulator cor. Moreover, the input of the reference aperiodic link is connected to the input of the current regulator cor, and the output of the link is connected to the regulating input of the control element, to which the current sensor kor is connected via an inverting amplifier. ELECTRIC MOTOR

The known device minimizes the deviation of the current of the core from the optimal one and the invariance of the regulation of the current of the core. In this case, in the possible range, the changes and disturbances acting on the current circuit of the core l are compensated.

However, the known device does not provide the limitation of the current in the event of a malfunction of the reference aperiodic link, the controller and the current sensor, the excitation winding, etc., which limits the functionality of the device.

The purpose of the invention is to extend the functionality by providing protection of the electric motor in case of malfunction of the device elements.

The goal is achieved by the fact that two chains are inserted into the device on a series-connected selector that exceeds the signal above a given level, the adder, the integrator and the relay winding, the switch terminal of which is connected by a common point to the integrator output

The raster, the closing part of the switching contact is connected through the input resistor to the integrator input, and the opening part of the switching contact through the input and counter-connected zener diodes to the adder, while the connections of the mentioned chains are connected separately to the device input and to the input of the control element.

FIG. 1 shows a functional diagram of the proposed device; Fig.2circuit integrator ..

The device contains ave points 1 and 2, with point 1 being the input and the devices, and point 2 being the input to the control element. Points 1 and 2 are connected to identical chains consisting of each of the series-connected separator 3 (4) exceeding the signal above a given level, the adder 5 (6), the integrator 7 (8), the windings of the relay 9 (1О). In parallel with the winding of the relay 9 (10), a capacitor 11 (12) is connected. The closing contact 13 (14 relays 9 (10) is connected through a resistor

15 (16) to the input of the integrator 7 (8), and its disconnecting part 17 (18) is connected via a series and counter-connected zener diodes 19 (2O) to the input of the adder 5 (6). Other contacts of this relay are included in the protection circuit (not shown in the drawing). In addition, the input of the current regulator 21 of the cor, the output of the sensor 22 of the current of the cor and the reference aperiodic link 23 with feedback through switching and dynamic parameters, the input of the inverting amplifier 24 and the output of the control element 25 are connected to point 1. To point 2. which is the input of the control element 25, the outputs of the reference aperiodic link 23, the amplifier 24 and the regulating input of the control element 25 are connected whose second input together with the input of the converter 26 is connected to the output of the current regulator 21. The output of the valve Converter 26 successively with the input of the sensor 22 is connected to the bark 27 of the electric motor. The integrator 7 (8) contains an operational amplifier 28 spanned by an integrating aepochi (from capacitor 29 and non-linear feedback from resistors AOR and 31 and diodes 32. The proposed device works as follows. If there is no signal at point 1, the signal is absent at the output of the regulator 21 current k.or, valve converter

26, the current sensor 22 of the core, aperiodic reference link 23 and on the regulating section of the control element 25. The feedback between the output and the input of the regulator 21 is minimal and the gain of the regulator 21 is maximum.- Therefore, when a signal appears at the input of the device i.e. at point 1, the maximum signals appear at the output of the regulator 21, the converter 26 and the terminals of the core 27, which causes a rapid increase in the current of the core 27, the signal at the output of the sensor 22, the inverting amplifier 24, i.e. at point 2. The signal at point 1 also acts on the input of the reference link 23 and the signal begins to rise at a given speed at the output. In normal mode, point 2 quickly becomes balanced and the signal of the inverting amplifier 24 exceeds the output signal of the reference signal. link 23. The gain of the regulator 21 is limited, which stabilizes the magnitude and law of current change in the core 27. When a large signal is applied to the input of the device (point 1) or a large mismatch occurs at point 2, selector 3 (4) exceeds signal above a given level separates this excess, which leads to the appearance of a signal at the input of adder 5 (6)., its output and the input of integrator 7 (8). In the absence of disturbances in the mode of operation of the electromechanical system (for example, jamming in the mechanism, an open circuit in the field windings, etc.), the signal level at points 1 and 2 rapidly decreases, the capacitor 29 is discharged through resistor 31, diodes 32 and integrator 7 (8) returns to its original state. This discharge is accelerated due to the nonlinear nature of the direct resistance of diodes 32. If there is a violation (malfunction of the reference aperiodic link 23, jamming in the mechanism, etc.) in the electromechanical system or elements of the control circuit, the signal level at points 1 and 2 does not decrease in a timely manner. The excess of the signal over a predetermined level is integrated and the voltage at the output of the integrator 7 (8) reaches a value sufficient to open the zener diodes 19 (20). Through the zener diodes 19 (20) and the adder 5 (6), a positive feedback is formed (since it covers an even number of links), which ensures a rapid further increase in the voltage on the winding of the relay 9 (10) and the condenser 11 (12). Relay 9 (10) is activated and its contacts in the protection and alarm circuit (not shown) make the necessary switchings. At the same time, the switching contact of the relay breaks its disconnecting part 17 (18) and the positive feedback acting through the zener diodes 19 (2O) is cut off, and the closing contact 13 (14) of the relay 9 (10) discharges the capacitor 11 (12) through a resistor 15 (16 ). After that, i "tegrator 7 (8) returns to its original state. At this time, the relay 9 (1O) remains on until the voltage on the capacitor 11 (12) drops to the release voltage of the relay 9 (10).

Claims (1)

1. USSR author's certificate number 656169. cl. H 02 P 5 / OO, H O2 P 5 / O6, 1977.