RU2656999C1 - Swivel platform multi-motor drive - Google Patents

Abstract

FIELD: electrical equipment.

SUBSTANCE: invention relates to the field of electrical equipment and can be used in control servo-systems. Swivel platform multi-motor drive contains n of identical motors uniformly placed along the platform perimeter, each of which is equipped with m-phase rotor position and its rotation speed sensors, as well as control unit. At that, adjoining motors rotors (or stators) are identically turned in space (clockwise or counterclockwise) by the angle

providing these sensors output voltages phase shift to the electric angle of radians

.

EFFECT: technical result is increase in the platform (and load) rotation smoothness and expansion of the drive bandwidth.

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Description

The invention relates to electrical engineering and can be used in servo control systems.

Known drives of rotary devices containing control units and electric motors [1], the disadvantage of which is the complexity and cumbersome design of the engines when used in drives of rotary platforms [2].

Closest to the proposed solution is a multi-motor drive of a rotary platform, containing n identical motors equally spaced along the platform perimeter, equipped with m-phase sensors of rotor position and speed of rotation, as well as a control unit [3].

The disadvantage of this drive is the limited smoothness of rotation (mainly caused by the non-sinusoidality of the stator currents), especially when using discrete (or analog, but with a discrete output [3]) rotor position sensors, as well as a large time constant of the smoothing filter at the output of the speed sensor, limiting the band drive transmission.

, обеспечивающий сдвиг фаз указанных датчиков на электрический угол

радиан, где n - число двигателей, Z - число зубцов магнитопроводов двигателей, m - число фаз датчиков положения ротора.The technical result of this proposal is to increase the smooth rotation of the platform and expand the bandwidth. The specified technical result is achieved by reducing current ripple in the motor windings and reducing ripple at the output of the speed sensor. For this, in the well-known multi-motor drive of a rotary platform, containing n uniformly uniformly distributed motors along the platform perimeter, equipped with m-phase sensors for rotor position and rotational speed, according to the invention, the rotors or stators of adjacent motors are equally rotated in space

providing a phase shift of these sensors by an electric angle

radian, where n is the number of motors, Z is the number of teeth of the magnetic circuits of the engines, m is the number of phases of the rotor position sensors.

In FIG. 1 shows (conditionally) the placement of multi-motor drive motors on a platform. In FIG. 2 presents a structural diagram of the proposed drive. In FIG. 3 shows the electrical circuit of one phase of a three-phase power amplifier with a shaper of control signals at the input. In FIG. 4 shows a diagram of a speed sensor with an inlet filter.

The drive contains four (in the general case) n identical actuating engines 1-4 (Fig. 1), placed evenly around the perimeter of the platform, in the center of which the load 5 is located along its rotation axis (for example, theodolite [2]). Motor windings are connected in series in order to evenly distribute the load across all motors.

, где Z - число зубцов статора двигателя, например, с зубцовым шагом обмотки, при этом электрический угол

радиан. В качестве измерителя скорости вращения двигателя используют тахометрические обмотки, размещенные на зубцах с ДХ.Actually, the drive is made with a torque control method [3], in which the engine moment corresponds to the input signal, in this case, the total moment of four engines. As motors, asynchronous motors with a tooth pitch of the winding are usually used, and as a rotor position sensor, a set of Hall sensors (DC) located on the teeth of the motor [3]. In this case, each motor is equipped with three (by the number of phases m) DCs, which are usually located on three adjacent teeth of the magnetic circuit. The stators (or rotors) of the motors are rotated in space at a certain angle Δβ, for example, clockwise. Therefore, with respect to the first, the second engine is rotated at an angle Δβ, the third at an angle of 2Δβ, and the fourth at an angle of 3Δβ. In the case when the DC are located on three adjacent teeth (which is not always the case), then the angle

where Z is the number of teeth of the stator of the engine, for example, with a tooth pitch of the winding, while the electric angle

radian. As a measure of engine speed, tachometric windings are used, which are located on the teeth with DC.

The engines are controlled from the control unit, which, in addition to electronic devices, also contains a power supply. The block diagram of the drive is shown in FIG. 2.

It contains an executive motor 1 (equal in power to four engines of a real drive), a rotor 6 position sensor at N = n⋅m = 12 DX, a rotation speed meter 7 on twelve sections of tachometric windings, a power amplifier 8 with a control signal shaper 9 at the input, a voltage converter 10 of the speed meter 7 into a DC reverse signal with a filter 11 at the output, as well as an input device 12. In addition, the circuit includes a power reducer 13, load 5, instrument gear 14 and an angle sensor 15, which is a g sensor avnoy feedback.

, то форма сигнала i_y и статорного тока двигателя будет иметь вид квазисинусоидальной ступенчатой кривой с n⋅m ступенями в полупериоде (см. фиг. 3).The power amplifier 8 (Fig. 3) in torque drives is performed as a current regulator, for which it is covered by negative current feedback using a current transformer 16. The power amplifier is controlled from a control signal shaper 9 that sets the magnitude and shape of the stator current curve of the motors. Shaper 9 is built on n⋅m resistive-key circuits [3], the keys of which are controlled by the DX signals of FIG. 3, where n⋅m is chosen equal to 4⋅3 = 12. The total signal of these circuits is the control signal i _{y of the} power amplifier. Since the output signals of the DX are phase shifted by an angle

, then the waveform i _y and the stator current of the motor will have the form of a quasi-sinusoidal step curve with n⋅m steps in the half-cycle (see Fig. 3).

With this form of current and a sinusoidal form of flow, the expression for the moment has the form [3]:

In this case, the amplitude of the pulsation of the moment is determined by the formula:

For the case under consideration, when n = 4, m = 3, the value ΔM` = 0.85%.

A voltage transducer 10 of the rotational speed meter 7 was built in a similar way, the combination of which forms a DS speed sensor.

In FIG. 4 shows a diagram of a DS with a filter 11 at the output. The converter 10 is built as a synchronous detector (rectifier) of the output voltages n⋅m of the tachometric winding section of the motors and contains n⋅m (12) resistor-key circuits controlled by DX signals. The output signal DS is the total current i _DS n Дm resistor-key circuits, the expression for which has the form [3]:

and the range of velocity pulsation will be determined by the formula:

In FIG. 4 shows the shape of the output signal, where i _ДС values n⋅m = 12. If it is necessary to reduce the value Δi _DS at the output of the converter 10, you can turn on the filter 11 on the operational amplifier, as shown in FIG. four.

The input device 12 (Fig. 2) contains two comparison nodes to which are supplied: a reference signal U _α1 , a signal U _α2 from the output of the angle sensor 15 and a signal from the speed sensor U _Ω from the output of the filter 11. In addition, the input device contains amplifiers that form voltage ± U _y (Fig. 3) for the shapers of the control signals 9.

The drive operates as follows. When a reference signal U _{α1 is} supplied to the drive input, the input device generates a voltage ± U _s at the output to supply control signals to the driver input. The latter generates a control current i _y , providing the required output current of the power amplifier. The consequence of this is the formation of torque on the shaft of the engine (or engines). If the value ΔU _Ω = U _α1 -U _α1 -U _αΩ turns out to be positive, the drive starts to gain speed, and if it is negative, then the drive starts to slow down with a subsequent reverse when the value of U _{α1 is} negative.

Thus, the proposed multi-motor (four-motor in this case) drive provides higher smoothness of rotation (the ripple of the moment and the output voltage of the speed sensor is reduced by 16 times compared with a multi-motor drive without reversing the ID stators with an increase in the ripple frequency by 4 times). The latter, in particular, makes it possible to reduce the filter time constant, thereby expanding the drive bandwidth.

Information sources

1. A.c. USSR No. 978242. Drive slewing device. B.N. Karzhavov, V.N. Brodovsky, Yu.P. Rybkin et al. 1982, No. 44.

2. High-precision control systems and drives for weapons and military equipment / Edited by V.L. Solupina. M.: Publishing House of MSTU. Bauman, 1999

3. Baranov M.V., Brodsky V.N., Zimin A.V., Karzhavov B.N. Electric servo drives with torque control of executive motors. M.: Publishing House of MSTU. Bauman, 2006

Claims (1)

A multi-motor drive of a rotary platform, containing n identical motors equally spaced along the platform perimeter, equipped with m-phase sensors for rotor position and speed of rotation, characterized in that the rotors or stators of adjacent motors are equally angled in space

providing a phase shift of these sensors by an electric angle

radian, where n is the number of motors, Z is the number of teeth of the magnetic circuits of the engines, m is the number of phases of the rotor position sensors.

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