SU686134A1 - Synchronized dc electric drive - Google Patents

Description

one

This invention relates to the field of adjustable DC electric motors. The drive is intended for use in frequency synchronization systems.

A synchronized DC motor 1 is known. It contains a switch through which power is supplied to the motor, a synchronization unit connected to the switch, one of the inputs of which is supplied with a synchronizing frequency, and the other is connected to a frequency rotation speed sensor connected to the motor shaft.

The speed sensor signal has a frequency proportional to the speed of rotation. The synchronization block, which controls the motor through the switch, ensures that the frequency signal of the speed sensor and the synchronization frequency are equal by phase locking. In this way, proportional to the rotational speed of the synchronizing frequency, i.e. synchronization is in progress.

However, at low values of the synchronization frequency, i.e. At low speeds, the frequency of information on the phase position of the rotor is low, which degrades the quality of regulation and leads to a breakdown of the phase-locked loop (sensor signal). This narrows the adjustment range.

Thus, the disadvantages of the known device are narrow

0 synchronization range and low control quality at low speeds.

Closest to the invention

5 The technical solution is a non-contact DC motor with a synchronous rotation speed of 2. It contains a t-phase switch, a unit connected to it

0 synchronization, to which a rotational speed sensor is connected, such as inverted contactless selsyn, connected to the t-phase frequency reference oscillator and connected to

5 by the switch through the decoders, each of which with two inputs is connected to the output of the sensor, and the other inputs - to the corresponding phase of the reference frequency generator.

0

The frequency f of the output signal of the speed sensor is determined by the expression

f fo F, (1) where fj, the reference frequency,

F is the frequency of rotation of the electric motor.

The sign before the value of F is determined by the direction of rotation. The output signal of the speed sensor carries information about the direction of rotational speed and the phase position of the rotor. With the help of a synchronization unit, a phase self-tuning of the rotational speed is provided, that the frequency of the output signal of the speed sensor and synchronization frequency f are equal to

f f (,, FO ± F f о (2)

Thus, the frequency of rotation of the motor is determined by the expression

F / fc - fo / (3)

As can be seen from expression (3), the instability of the reference frequency causes the instability of the rotational frequency, which violates the uniqueness of the relationship between the magnitude of F and the synchronizing frequency, t leads to a synchronization error.

The speed of such an electric motor is synchronized with an error related to the instability of the reference frequency generator.

The purpose of the invention is to improve the synchronization accuracy by eliminating the synchronization error associated with the instability of the reference frequency generator.

The goal is achieved by the fact that a 3 synchronized DC drive containing a power unit, to the control input of which a synchronization unit is connected, a rotational speed sensor with an output characteristic of the form ff ± kF, the output of which is connected to one of the inputs of the synchronization unit, is t-phase a reference frequency generator, connected to a rotational speed sensor, and a frequency setting device, a frequency adder is inserted, one input is connected to the output of the reference frequency generator, the other is connected to the rear device frequency, and the output is connected to the synchronization unit.

Due to the introduction and the indicated switching on of the frequency adder, the influence of the instability of the reference frequency generator on the engine speed is eliminated. At the same time, the synchronization unit operates at a frequency close to the reference frequency, which means that the frequency of information about the phase position of the rotor at all frequencies of rotation is high, which, in turn, provides a wide range of synchronization and high quality control.

On the preface. block diagram of the proposed electric drive; in fig. 2 shows the cyivtMHpoBaHHH block.

The electric drive contains electric motors 1p power unit 2, sensor 3, frequency of frequency, frequency, generator of frequency reference 4, synchronization unit 5, frequency adder 6 and device 7 for setting frequency of turn 11.

The outputs of the power unit are connected to the motor winding, and a rotational speed sensor is connected to the motor shaft, to the input of which the phase generator of the reference frequency is connected. The output of the synchronization unit 5 is connected to the power unit 2, one of the inputs of the synchronization unit is connected to the output of the sensor 3, the other to the output of the frequency adder 6, one of the inputs of which is connected to the home of the reference frequency generator 4, and the other input receives the synchronizing frequency from the device 7 set rotational speed.

The scheme works as follows.

The signals from the t-phase generator 4 of the reference frequency are fed to the inputs of the rotation frequency sensor 3. The signal of the frequency sensor vralen, arriving at one of the inputs of the synchronization unit 5, has a frequency

f fo ± F (4) The sign before the value of F is determined by the direction of rotation.

The cyT.CvsaTopa frequency inputs are 6 posg, the signals from generator 4 and the clock frequency from the rotational speed reference device 7 are fed. At the output of the adder frequency signal has a frequency f J defined by the expression

(five)

f fn ±

with ,

where FP is the sync frequency

speed setting devices,

The sign before the F value is determined by the direction of rotation,

Using the synchronization unit 5, which controls the electric motor 1 through the power unit 2, phase rotation of the rotational frequency is controlled so that the frequencies of the input signals of the synchronization unit, t, e,

f 4 F fo ± FP (6)

The reference frequency is included as a term in both parts of equality (6) Thus, the instability of the reference frequency does not violate equality (b) in any way and does not cause synchronization errors. The rotation frequency is determined only by the synchronization frequency.

(7;

F fe

Claims (2)

The frequency adder b can be constructed, for example, according to the scheme (FIG. 2) containing controls of the local oscillator 8, frequency mixer 9, the node of the phase-locked frequency control 10. The output of the local oscillator is the output of the adder and is connected to one of the inputs of the mixer; is one of the inputs of the adder connected to the output of the generator 4 of the reference frequency The output of the mixer is connected to one of the inputs of the phase locked loop 10, the other input of which is the input of the adder to which the clock frequency of the device 7 is fed and the output of the nodes avtopodstroy ki and phase is coupled to a control input of the local oscillator 8, node C via a phase-locked loop, control hetero din, a mixer 9 and a synchronizing frequency output signal frequency provided equality, i.e. FCM FC (8) The mixer output signal has a difference frequency (beat frequency) of the signals coming from the local oscillator and the 4 reference frequency generator. Thus, the frequency at the mixer output is also determined by the expression FCH-I 1-fo / (9) From the expressions (8 ) and (9} follows, f fo t FC (10) The sign before the value of Fp is determined by the sign of the difference (9). In accordance with expressions (6) and (9), the local oscillator frequency must be correspondingly greater or less than the frequency f depending on from the voltage of the motor to the motor “From the comparison of expressions (10) and (5 it can be seen that the circuit in Fig. 2 has provided There is no cy / I frequency operation, the use of a frequency adder specified in the description of its inclusion in the circuit is favorably distinguished by a synchronized non-contact direct current electric motor since it ensures the synchronization of the argive speed without error associated with the inherent stability of the reference frequency generator. A synchronized motor will facilitate the construction of precision adjustable and synchronized drives used in various fields of technology. Claims of the invention. Synchronized DC drive containing a power unit, to the control input of which a synchronization unit is connected, a rotational speed sensor with an output characteristic of the form ff (jt kF, where f is the output frequency, fo is the reference frequency, k is the coefficient, F - rotational frequency, the output of which is connected to one of the inputs of the synchronization unit, m - phase reference frequency generator, connected to the rotational speed sensor, and a frequency setting device, characterized in that, in order to increase exactly This synchronization is performed by eliminating the influence of the instability of the reference frequency generator, a frequency adder is inserted into it, one input of which is connected to the output of the reference frequency generator, the other is connected to the frequency setting device, and the output is connected to the synchronization unit. attention in the examination 1. US patent number 3553555, CL 318-314, 05.01,71. 2. USSR author's certificate number 379031, cl. H 02 P 5/16, 1970 (prototype). Figg