SU411599A1 - - Google Patents

Description

Invented by the RSDP .. and sobromatic is regulated; speeds of multi-motor electric drives with three-phase asynchronous short-circuited electric motors and static frequency converters1 1. The special feature of tahnh drives is that. That xinhroppie engines have a rigid mechanical connection between themselves through the coupling of the wheel with the rail. In the general case, the angular velocities of rotation of the rotors of individual engines are different (even with the same machine parameters) due to technological and operating deviations of the BajaG diameters: wheel sets around the circle, so special measures should be taken; 1; Direct loading between traction motors.

Known ma-iBO length servo cKopocii multi-motor drive AC separated koiturami reguliropmsh-i: voltage and frequency comprising a frequency zidayuiy generator iredvaritelnym usilntelem for uiravleii inverter and sensors motor current acting through the logic "OR on controller 5ozbuzhdenn synchronous generator.

For control, pacnjHpcHiiii of the range of the regulator,) osI, and at the same time, at the same time, aviivan nag (1u:; o); | ect) move 2

ycTpoiicTBO offered by the magnetic flux sensors and permanent sensors for each position of the onorp signal, which, through the additional logic circuit OR or the unit of the motor current sensors, act on the preamplifier of the driving oscillator.

FIG. 1 is a block diagram of the device described; in fig. 2 - mechanical characteristics of the asynchronous drive.

The synchronous generator 1, via driver 2 and inverters 3, supplies the induction traction motors 4. The motor currents are measured by current sensors 5, the output signals of which are fed to the input of the OR 6 logic circuit, which selects the largest of the signals. A sigpal, normal to the current of the most loaded engine, is fed to the input of the excitation controller 7, which forms the family of the required external characteristics of the power unit 1-3. To control the inverters 3, a master oscillator 8 and a control unit 9 are used.

The selection of the error signal acting on the master oscillator 8 is based on compensating for the deviation of the real correlation between the phase voltage and the frequency of the supply of the traction motors from the one specified by the introduction of negative feedback on the magnetic flux of the motors. A signal proportional to the magnetic flux is generated by means of the magnetic flux sensor 10, made, for example, in the form of a simplified physical model of a replacement engine for a traction motor. The signal from sensor 10 is fed to one of the inputs of an additional OR OR logic circuit, to the other input of which a reference signal is constant for each position from sensor 12. The largest of these signals in comparison unit 13 is compared with a signal proportional to the current of the motor taken from sensor 5. The differential signal amplified by preamplifier 14 is fed to the input of master oscillator 8, which converts the analog electrical signal B to a sequence of pulses of the required frequency.

When starting the locomotive, when the generator current is limited through the excitation channel. The speed control system maintains the magnetic flux of the traction motor at a predetermined level. In a constant power zone, the magnetic flux decreases in proportion to the motor current, due to the fact that the frequency at the output of the inverter unit increases faster than the voltage. In the startup and constant 1n-1 power modes, the traction motors operate at almost constant absolute slip, close to optimal. The setting in the control system is sigpal for the current of the traction motor of this control channel.

At output B, the nanopart restriction zone signal proportional to the motor magnetic flux becomes less than the constant reference signal received at the second input of the PLI 11 logic circuit. Then the motor current signal in the error meter is compared with a constant onor signal, which in this mode Drive operation setpoints for speed control system5. In the event of a decrease in the current of the traction motor 4, for example, when the moment of resistance decreases, the device produces such a frequency of the supply voltage to maintain the current of the engine at a low level. In this mode, the engine is running at constant voltages on the current and at a non-temporary power frequency.

Thus, the proposed device provides a wide control of the speed of the traction motors, which is necessary to obtain a high transmission ratio. Three zones of speed control of traction engines are clearly expressed:

one,

1. - - const, /: const.

Ii.

 const, PI const.

VI

Iii. / var, I,: const, / 1 const.

Satisfactory dynamic indices of a traction electric drive are obtained by introducing into the circuit a frequency control of a serial corrective element. It also improves the anti-blocking properties of the locomotive, allowing the dynamic modes to use the natural hard mechanical characteristics of asynchronous motors. The role of the successive corrective element is performed by the preamplifier 14, while giving it an appropriate transition characteristic.

In order to reduce the response time of the system when powering on after run-up or during start-up, a locomotive speed tracking unit 15 is used, for example, powered by a locomotive speed meter.

The advantage of the device is also the tendency to equalize the loads between the osmotor blocks when individually controlling the frequency of the power of the traction motors due to the regulation of the magnetic flux of each of the motors is proportional to the current of the same motor. When the current of any motor decreases from the current of the most loaded motor, the frequency of the first motor's motor automatically rises and compensates for the difference in currents.

Subject invention

An apparatus for automatically controlling the speed of a multi-motor AC drive, mainly for traction purposes, comprising a frequency master oscillator with a pre-amplifier for controlling the inverter and motor current sensors acting through the OR circuit on the synchronous generator excitation regulator,

that, in order to simplify, expand the speed control range and improve the dynamic qualities of the drive, it is equipped with magnetic flux sensors and constant signals for each position of the reference signal, which, through an additional OR or logic circuit, compare the preamplifier specifying a cheperator.