SU738080A1 - Device for regulating dc electric motor speed - Google Patents

Description

The invention relates to electrical engineering and can be used to regulate the speed of direct current drives with AC power through a gate converter. Devices are known for regulating the speed of a DC electric drive of a DC drive, including an analog or discrete setting device, analog or discrete controllers and position and velocity sensors, analog controllers and current sensors. Control devices built on analogue controllers and sensors can be divided into three types having different structures. The simplest device consists of one controller, the input of which receives the error signal between the specified and actual values of the controlled parameter (voltage or speed of rotation of the motor) and a non-linear current feedback signal 1. At a current less than the specified limit value, the circuit It works as a voltage regulator or speed regulator, and when this value is exceeded - as a current regulator, such a single-loop control circuit does not allow the regulator to be optimally adjusted, since Meth function of current and voltage circuits (speed) are different. It is also known a device for regulating the speed of an electric motor, which contains two independent of them alternately operating ch circuits with separate regulators 2. However. the disadvantage of such schemes is their complexity. The most common at the present time are the schemes of subordinate adjustment of parameters. In terms of their dynamic performance, the LEDs are almost equivalent to dual-circuit systems, parallel to the action, but their number of elements are exchanged, are simpler and easier to set up. 3. Control devices on analog elements do not meet the increased requirements for the accuracy of industrial units. They lack the ability to directly interface with digital computing units and various kinds of software by notifying devices.

738080 Closest to the invention. The technical solution is a device for controlling the speed of a direct current electric motor connected to the AC network through a valve converter containing a discrete reference unit, a digital calculating unit that performs the function of a speed controller, a discrete speed sensor, Shb and Bb regulators of current speed and 5b6t are related sensors of speed and current 4, -; - - A disadvantage of the known device is the presence of significant (HOLICHES elements made on various components, complicates the technology of manufacture, operation and reduces the reliability of the device. The purpose of this invention is to improve the reliability and simplification of the device. .. -. This goal is achieved By that, 5N6Jyo6dyshkryt G average value of the current of the motor core, switches, serially connected by the synchronization unit, input, connected to the power supply unit and the frequency division unit, you One of which is connected to a digital computing unit, a serially connected conversion unit and a pulse distribution unit, the output of which is connected to a valve converter, and the input of the converter unit is connected via a switch to a digital computing unit to which a speed sensor and a jail is a job, and the control inputs of the digital-to-voltage code conversion unit, the pulse distributor and the switch In their circuit are interconnected and connected The output of the synchro sync block and the digital computing unit, and the interconnected control inputs of the sensor of the average current of the core of the electric motor and other switches to the output of the frequency division block. The invention is illustrated in the drawing, which shows a block diagram of a device for a regulator and a dc electric device. The device contains a digital computation module, a discrete speed sensor 2, mechanically connected ; with a coil 3 eLectrodvigotatG - direct current, connected via valve converter 4 to an AC network and through switch 5 to digital computer to computing unit 1. Input of digital computing unit 1 through switch 6 arrives: Disconnect from Discrete unit 7 tasks, Device is equipped with an in-synchronization unit 8, the input of which is connected to an AC network, a frequency divider 9, connected to a digital comp. The digital unit 1. .. A discrete atch 10 of the mean current value of the motor armature, the pulse distribution unit 11 and the digital code-to-voltage conversion unit 12 are entered into the device. The input of the discrete sensor 10 is connected to the motor current sensor 13, and the output is via a switch 14c with a digital computing unit 1. The input of the block 12 through the switch 15 is connected to a digital computing unit and the output is connected to the input of a pulse distribution unit 11 connected to the valve converter 4. The control inputs of the pulse distribution unit 11, the digital code conversion unit 12 into a voltage pulse are interconnected and connected to a digital computing unit. 1 and to the output of block 8 synchronization. The control inputs of the discrete sensor 10 of the average current of the motor core and the switches 5, 6, 14 are also interconnected and connected to the digital computing unit 1 and to the output of the frequency dividing unit 9. A device for controlling the speed of an electric motor operates as follows. In block 8, synchronization is allocated at times corresponding to, precisely: the natural switching of the gates, the synchronizing pulses. The points of the actual commutation are determined by comparing the anode voltages of two adjacent valves in the sequence. . The moment of equality of the corresponding stresses characterizes the indicated point. The output signals of the synchronization unit are supplied to the pulse distribution unit 11, the digital code conversion unit 12 to the voltage pulse, the switch 15, the frequency division block 9 and the computing unit 1. The output of the block 9 is fed to the control inputs of the comp. mutators 5,6,14, digital computing unit 1 and discrete sensor 10 of the average value of the current of the engine core. The frequency of these signals is a multiple of the frequency of the clock pulses of block 8. For each signal of block 9, information from the discrete sensor 10 of the average value of the motor current yor, the discrete speed sensor 2 and the task block 7 is entered into the computing unit 1 via switches 5, 6, 14. In addition, the information of the sensor 10 is reset to zero and the measurement of the average current of the trigger voltage to the arrival time of the signal from block 9 begins. Measurement of the average value of the motor current is performed by integrating (summing) the instantaneous values of the current. By the signals of block 8 from computing unit 1, a switch 15 is output to block 12 to convert a code into a voltage pulse code corresponding to the angle of control of the converter converter. In block 12, the numeric code converts to a voltage pulse shifted from the point of natural switching of the gates by time, efficient to the code. The voltage pulse goes to the unit.

The distribution of pulses, where it is amplified in power, is galvanically released and supplied to the corresponding valves. Switching the output signals of block 11 in different directions is carried out on the signals of blocks 12 and 8. If in block

12, the code corresponding to the control angle, exceeding the following period of the clock pulses produced by block 8, the next received clock stops the conversion of previously received information to the arrival of the next clock pulse, and the new corrected code is entered from the computing block and begins its conversion.

The frequency of the clock pulses is equal to the ratio of the frequency of the mains supply to the phase of the converter. For a whole range of electric drives, for example, mine lifting electric drives, rolling mill conveyors of rolling mills, drilling rigs, etc. the maximum adjustment frequency can be 2-3 times less than the clock frequency. Therefore, in order to reduce the speed requirement of the computational unit, the division unit is executed with an adjustable division factor, which at the same time allows, if necessary, control by means of the computation unit by several independent actuators. I

The advantages of this device are in high reliability with small dimensions and weight, high degree of unification; measurement of the transfer functions of the controllers implemented in the computer is carried out by changing its work program; possibly

control one device by a group of electric motors; the accuracy of adjusting complex modes is high; possible direct communication of local digital regulators with control devices of the highest level; Tf3 prepared device is not difficult.

Claims (1)

1. USSR author's certificate 5 № 316104, class, G About J 3/00, 1971, 2, USSR Copyright Certificate №416670, cl. G 05 B 13/00, 1974, 3, USSR Author's Certificate No. 436425, class, H 02 P 5/50, 1974, 0 4, Slezhanovsky O.V., and others. The device of a unified block system regulation, M, Energie, 1975, s, 8-15,