SU1334340A1 - Device for controlling current of d.c.electric motor - Google Patents

Abstract

This invention relates to electrical engineering and can be used in direct current drives. The aim of the invention is to reduce losses in a bridge reversing converter and to ensure the linearity of the adjustment characteristic of the electric drive in braking conditions. The device contains a difference calculator 9, the first input of the differential calculator 9 is connected to the input of the polarity indicator 7 and the driver input of the relay current regulator 3, the rotational speed sensor 4, the output of which is connected to the second input of the differential calculator 9. The output of the computer of the difference 9 is connected to the input of the indicator 6 mode. The operation of the bridge reversing converter in one of the programs and the transition from one program to another is provided by the distribution of pulses depending on the current reference signal and the signal determining the difference between the measured rotational frequency and the magnitude of the static drop in the rotational speed of the motor shaft. 2 Il. 00 00 4 00 4

Description

 1334340

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

The purpose of the invention is to reduce losses in the bridge reversing converter and to ensure the linearity of the adjustment characteristic of the electric drive in braking conditions.

Figure 1 shows a diagram of a device for controlling the current of a direct current drive electric drive; Fig.2 is a diagram of a bridge reversing converter with a reverse diode bridge.

The device for controlling the current 15 of the direct current motor comprises an electric motor 1 connected to a bridge reversing converter 2 with a reverse diode bridge, a relay current regulator 3, a sensor 4 rotating speed 4 connected to the output of the electric motor 1, a current sensor 5, an output which is connected to the feedback input of current regulator 3, indicators of mode 6 and 25 polarities 7, pulse distributor 8, the output output chip of which is connected to the inputs of bridge reversing converter 2, difference calculator 9. Moreover, the first input of the computer of the difference difference 9 is connected to the input of the polarity indicator 7 and the driver input of the relay current regulator 3. The output of the rotational speed sensor 4 is connected to the second input of the differential calculator 9, the output of which is connected to the indicator indication of the 6th mode, the output connected to the first input of the distributor 8 pulses, the second input of which is connected to the output of the polarity indicator 7, and the third input connected to the output of relay control current 3.

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The device works as follows

Four switching programs of the bridge reversing converter are used to control the motor current. The operation of the bridge reversing converter in one of the programs and the transition from one program to another is provided by the distribution of pulses depending on the signal for the current I and the signal determining the difference between the measured rotation frequency w and the magnitude of the static drop in the rotation frequency of the motor shaft

/ 1 W

g and

TO,

de g- - the resistance of the core chain.

M

Kg - engine emf coefficient.

In the case when the sign of the specified current coincides with the sign of the specified difference

Ij70, w-iiu) 70 (I O, w-y) O), for controlling the current, the first (third) program of switching keys of the bridge reversing converter 2 is used, which means that the core winding is connected to the power source to increase the current keys 10. and 11 (12 and 13). The current from the power source flows through the circuit: (+) power source, key 10, measles engine 1, shunt current sensor 5, key 11., (-) power source, ((+) power source, key 12, shunt current sensor 5 Measles of electric motor 1, key 13 (2) of the power source). To decrease the current, switch off key 11 (13), which provides current flow circuit: key 10, measles of electric motor 1, shunt of current sensor 5, diode 14 (key 12, shunt of current sensor 5, measles of electric motor 1, diode 15).

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In the case where the sign is given

current does not match the sign of the specified difference

I G 0, (l) -LS1 0 (1h

Oh, w-dw: 0),

for current control, the second (fourth) program is used, namely, to ensure the increase of current in the winding of the core in the dynamic braking mode, they include

key 13 (11), which provide current flow circuit: key 13, diode 16, shunt of current sensor 5, measles motor 1 (key 11, diode 17, measles of electric motor 1, shunt of current sensor 5).

To ensure the decay of the current in the regenerative mode, switch off key 13 (1 1) provides the current flow circuit: (-) power source, diode 16, shunt of current sensor 5, measles electric motor 1, diode 15, (+) power source ((()) power source, diode 17, measles of electric motor 1, shunt of current sensor 5, diode 14D + (power supply source).

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Let the motor shaft 2 be in a stationary state and 0. When a positive reference signal is applied to the current at the output of the difference calculator 9, which performs the operation, a positive signal appears (multiplication Ij by the value of Gd / Kp is carried in the calculator). At the output of the mode 6 and polarity 7 indicators, logical units (X 1, X2 1) appear. With such values of X and X, the distributor 8 pulses provides pererazm-

Switching bridge reversing converter 2 according to the first program. The switching times of the keys are determined by the relay current regulator 3 with a hysteresis characteristic that supports a given current within a given range of its deviation, which is determined by the loop width of this characteristic. The same program switches the keys in the case where JU) 7 0.

} When a signal is applied for braking Ij 0, a positive signal remains at the output of the difference calculator 9. At the output of the mode indicator 6, the level of the logical unit X 1 remains. At the output of the indicator 7 polarity, a logical zero X2 0 appears. The pulse distributor 8 provides switching of the keys of the bridge reversing converter 2 according to the second program. As a result of the deceleration, the rotation frequency drops and at the output of the calculator 6 times the positive signal decreases, and

drive behavior in the brake modes of its operation, a difference calculator is entered into it, with the first input of the difference calculator connected

at the moment when, due to O, it becomes the linearity of the adjusting character - with a negative one. At the output of the mode indicator 6, zero (X 0) appears.

Pulse distributor 8 switches the keys of the bridge-45 input of the polarity indicator and the driver input of the relay current controller, the output of the rotation speed sensor is connected to the second input of the differential calculator, the output of which is connected to the mode indicator input, the output connected to the first input of the pulse distributor, the second input which is connected to the output of the polarity indicator, and the third input is connected to the output of the relay current regulator.

go reversive converter .2 according to the third program. The current rises within the specified limits of its deviation in opposition mode, and decreases in dynamic braking mode, and the motor continues to decelerate.

If the reference signal is saved Ij 0, then after stopping the electric motor 1 goes into a motor mode and starts its acceleration

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th (third key switch program). The pulse distributor 9 provides the state of its output signals Y - Y4, depending on the input signals X and X, in accordance with the table.

X 1 X Т У, T УЛ УЗ Г У in .L -.

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Claims (1)

Invention Formula A device for controlling the current of a DC motor, comprising a motor, connected to a bridge reversing converter with a reverse diode bridge, a relay current controller, a rotational speed sensor connected to the motor output, a current sensor whose output is connected to the input feedback current controller, mode and polarity indicators, pulse distributor, four outputs of which are connected to the inputs of a bridge reversing converter, characterized in that, in order to reduce losses obespecheteristiki brake actuator in its working modes, it is entered in the difference calculator, with a first input coupled to the difference calculator  linearity of the adjusting  the input of the polarity indicator and the driver input of the relay current regulator, the output of the rotational speed sensor is connected to the second input of the differential calculator, the output of which is connected to the input of the mode indicator, the output connected to the first input of the pulse distributor, the second input of which is connected to the output of the polarity indicator, and the third input is connected to the output of the relay current regulator. 45 50 45 55 (rig 2