SU1601729A2 - Method of controlling single-winding motor of oscillating motion - Google Patents

Abstract

The invention relates to electrical engineering, in particular to the control of electrical machines and can be used to create drives for compressors and pumps. The purpose of the invention is to increase the stability of the magnitude of the working stroke of the moving part of the engine. A method of controlling a single-winding motor of oscillating motion is to periodically change the polarity of the supply voltage. Moreover, in each half-period, the changes in the supply voltage interrupt the power supply to the motor winding, after the current stops, the EMF is measured on the winding, the instant of change of its sign is recorded, and at this moment the power is turned on by the voltage of the opposite polarity, then the EMF derivative is measured on the winding the motor and the time interval between these moments, multiply the measured values among themselves, compare the resulting product with its reference value and maintain their equality by adjusting the amplitude of the pit present voltage. 2 Il.

Description

The invention relates to the control of electric machines, in particular for a gearless drive of piston pumps and compressors and is an improvement of the invention according to the authors. St. Ns 1398063.

The purpose of the invention is to increase the stability of the magnitude of the working stroke of the moving part of the engine.

FIG. 1 shows a block diagram of a device implementing the method; FIG. 2 - time diagrams.

The method of controlling a single-winding motor of oscillatory motion consists in periodically changing the polarity of the supply voltage, with each half-period of change in the supply voltage interrupting the power supply to the motor winding, after the current winding stops, the EMF is measured on the winding, and the moment of its change is recorded sign and c. this moment includes supplying the winding with a voltage of opposite polarity, measuring the derivative of the EMF on the motor winding and the time interval between these moments, multiplying the measured values with each other, forming a signal equal to the reference value of the product of these values, comparing the resulting product with the reference one and maintaining them equality by adjusting the amplitude of the supply voltage. Switching the polarity of the supply voltage of the engine at

its movable part of the extreme positions provides the resonant mode of operation, and the regulation of the amplitude of the supply voltage allows stabilizing the magnitude of the working stroke of the movable part of the engine, which increases the efficiency and stability of the operating characteristics of the systems in varying operating conditions.

A device for powering an electrodynamic motor of an oscillating system drive contains a constant voltage regulator 1 and a single-phase bridge connected to it with 1-switch elements 2-5 and shunt diodes 6-9, the output of which is connected to a load — an electrodynamic motor 10 with differentiating element 11 and a sensor 12 polarity of the voltage at its terminals, the output of which through the control unit 13 is connected to the control inputs of the driver 14 of the control signals, the differentiating link 11 and the timer 15, while the outputs of the pho The impeller 14 is connected to the key elements 2-5 and the feedback input of the control unit 13, the outputs of the differentiating element 11 and the timer 15 are connected to the inputs of the multiplier 16. The control input of the regulator 1 is connected to the output of the comparator 17, the inputs of which are connected to the outputs of the multiplier 16 and source 18 reference voltage.

The device works as follows.

A single-phase bridge converts a constant voltage at the output of regulator 1 into an alternating rectangular, zero-phase supply voltage for an electrodynamic motor 10 by alternately closing key elements 2-5 by a signal m Ua and UB of a calibrated duration (T), which is less than half the period natural oscillations (To) of a self-oscillating system of reciprocating motion, with a pause between them AT + Dg, Duration T is set so that until the moment of movement change of the moving part of the motor Atel voltage regulator is disconnected from its terminal and the transient reduction of the current engine 1dv (interval T A) is over.

The alternate generation of single-phase bridge control signals (Ua and UB) starts at the commands of unit 13 at the moments of polarity change of the EMF of the motor winding, which correspond to the extreme positions of its moving part and are fixed by changing the polarity of the signal at the motor terminals when there is no supply voltage ( zero stage), in block 13 using the output signal Ud of the polarity sensor 12. The output signal Uy of the block 13 supplied to the control inputs of the former 14, the differentiating link 11 and the timer 15 has the form of a short pulse of positive or negative polarity depending on the direction of the polarity of the emf

motor windings and, accordingly, the output signal Od of the sensor 12, which repeats the polarity of the signal at the terminals of the motor Udv. The polarity of the control pulse Uy determines one of the two outputs of the driver 14, which receives its signal, which eliminates the violation of the sequence of closure of the key elements of the bridge.

Simultaneously with the control signals of the single-phase bridge or the output of the driver 14, regardless of the polarity of the output pulses of block 13, the formation of feedback signals Uoc of a calibrated duration (T + Ac) begins, during which the polarity of the signal changes

at the terminals of the engine unit 13 is not fixed. The interval A t must be chosen from the condition:

thirty

-T

which eliminates the effect of the transient engine shutdown on the operation of the device and ensures the inclusion of the corresponding key elements 2-5 of the bridge at the extreme positions of the moving part of the engine.

At these moments, the differentiating link 11 and the timer 15 measure the derivative of the EMF on the motor winding and the time interval between these moments, the multiplied values are multiplied by the multiplier 16, the comparator 17 compares the resulting product with a signal equal to the reference value of the specified values from source 18 the reference voltage, and the output of the comparator is fed to the control input of the regulator

1 motor supply voltage.

When forming the supply voltage of the electrodynamic motor, for example, in the range from 0 to To / 2 (Fig. 2), the control signal Ua of the driver

14 during the time T, the key elements 2 and 5 are open, and the voltage regulator 1 is connected with the corresponding polarity to the terminals of the engine 10. Under the action of the applied voltage Upit

A 1d8 current flows in the motor winding, which, interacting with the excitation magnetic field, generates an electromagnetic force driving the moving part of the motor.

At time ti, corresponding to the end of signal Ua, the key elements 2 and 5 are closed. The energy stored by the inductance of the motor winding during the time of the transient AT for its shutdown (up to the moment ta) is recovered into the supply circuit in the form of a falling current 1dv through the shunt diodes 7 and 8. The voltage at the motor terminals (Unep) is doubled (at times ti and t2 of the beginning and end of the transient process changes its polarity. The signals from the polar sensor 12 by the control unit 13 are not recorded (pulses Uy, Fig. 2, shown by dashed lines), since the latter is blocked by the feedback signal Uoc of the former 14 until the moment rz overlapping the transient time AT.

At time t2, the motor current drops to zero. Since the moving part of the engine continues to move in the magnetic field of excitation, in the interval A g it works as a generator, the polarity of the EMF of the winding of which is not repeated by the output signal of the sensor 12, and the time t4 of its change corresponding to the extreme position of the moving part of the engine is fixed by the block 13.

Under the influence of the control pulse Uy, at time t4, the outputs of the former 14 show the signal UB to open the key elements 3 and 4 and the feedback signal Uoc for unit 13. The polarity of the voltage regulator connected to the motor terminals is opposite and its mobile part starts moving to another extreme position. Thus, fixing of the moments of reaching the extreme positions by the moving part of the electrodynamic engine and connection of the supply voltage to the motor terminals with alternating polarity at these moments is provided. The product of the values of the derivative of the emf at the motor winding (em) measured at the same time and the time interval between the beginnings of the adjacent half-periods of the supply voltage (To / 2) is maintained / constant by adjusting the amplitude of the voltage supplying the motor under the influence of the output signal of the comparator 17 to the control input of the constant voltage regulator 1.

Maintaining a given value of the specified product under any conditions of operation allows stabilizing at a given level the magnitude of the stroke of the engine's movable part, which, in accordance with the mathematical expression of the law of electromagnetic induction

.Vm

is proportional to this product, determined by the ratio

s - about Em I about. TO

AT

where Yesh is the amplitude of the EMF (motion) on the motor winding, the law of which changes over time is:

e EmSlnurt,

9

and the derivative at the time of changing the sign of the emf is equal to its amplitude

25 ei EmCosGrt | al l:

 E

; t

B - magnetic induction in the working gap of the magnetic system of the engine; i is the length of the motor winding;

30 (y-maximum value of the speed of a subspecies part of the engine;

S / 2 - the amplitude of the working stroke of the moving part of the engine;

w 2n: / That is the circular frequency of the own oscillations of the system.

Adjusting the amplitude of the motor supply voltage allows you to vary the amplitude of the EMF on its winding (Em) and thereby maintain the same value of 40 of the specified product and the working stroke of the moving part of the engine.

The process of forming the voltage of the electrodynamic motor power in the time interval from To / 2 to To is similar to 45 described, and then all the processes in the circuit are periodically repeated.

The proposed control method increases, in comparison with the known stability, the magnitude of the working stroke of the movable part of a single-winding motor of an oscillating system and is able to provide it with the required accuracy, increasing the stability of the system performance, by maintaining the specified value of the EMF amplitude on its winding and half-life duration

natural oscillations of the system in a wide range of load variations, supply voltage and environmental conditions.

Claims (1)

Invention Formula The control method of a single-winding motor oscillating motion on the author. St. No. 1398063, distinguished by the fact that, in order to increase the stability of the magnitude of the working stroke of the moving part of the engine, the derivative of the emf is measured on the motor winding at the moments of change of the EMF sign and the time interval between these moments, multiply the measured values among themselves, compare the product with its reference value and maintain their equality by adjusting the amplitude of the supply voltage.