RU2566671C1 - Rotor electromagnet suspension control system - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention pertains to electrical engineering and can be used in rotor mechanisms on electromagnet supports. In a rotor electromagnet suspension control system every control system channel incorporates a rotor position transducer (1), an integral regulator (3), a proportional controller (3), a differentiating element (4), a PD controller (5), a power transducer (6), two electromagnets (7 and 8), a setting unit (9), a proportional link (10), subtracting units (11 and 12), a sign extraction unit (13), a register (4), an adder unit (15) and a multiplexor (16).

EFFECT: faster operation, higher dynamic precision of the rotor electromagnet suspension.

4 dwg

Description

The invention relates to mechanical engineering and can be used in rotor mechanisms on electromagnetic supports.

The closest in technical essence is the control system of the electromagnetic suspension of the rotor (see patent of the Russian Federation No. 2395150, publ. 07/20/2010, bull. No. 20), in which each channel of the control system contains a rotor position sensor, an integral regulator, a proportional regulator, differentiating link, proportional-differential controller, power converter and two electromagnets.

The disadvantage of the closest control system for the electromagnetic suspension of the rotor is that in the ascent mode from the safety bearings when adjusting the regulators selected from the conditions for ensuring high speed, it becomes unstable. As a result, we have to deliberately reduce the speed of the system to ensure the operability of the electromagnetic suspension in all modes.

The essence of the invention lies in the fact that in the control system of the electromagnetic suspension of the rotor, each channel of which contains a rotor position sensor, an integral regulator, a proportional regulator, a differentiating element, a proportional-differential regulator, a power converter, two electromagnets, and the output of the rotor position sensor is connected to inverse the inputs of the integral and proportional regulators and the input of the differentiating element, the output of the proportional controller is connected to the direct input of the proportional of a national differential controller, the inverse input of which is connected to the output of the differentiating link, the output of the proportional differential controller is connected to the input of the power converter, to the output of which the windings of the electromagnets are connected, each channel is additionally equipped with a reference unit, a proportional link, the first and second subtraction blocks, and a selection block sign, register, adder and multiplexer, and the first output of the job block is connected to the input of the proportional link and the first input of the first block subtraction eye, the output of the rotor position sensor is connected to the second input of the first subtraction unit, the output of which is connected to the input of the sign extraction unit, the output of the integral controller is connected to the first inputs of the second subtraction and register unit, the output of which is connected to the first input of the adder, the second output of the task unit is connected with the first input of the multiplexer, the output of the proportional link is connected to the second input of the adder, the output of which is connected to the second input of the multiplexer, the output of the sign extraction unit is connected to the second input register and the third input of the multiplexer, the output of which is connected to the second input of the second subtraction unit, and the output of the second subtraction unit is connected to the direct input of the proportional controller.

Significant differences are expressed in a new set of connections between the elements of the device. The specified set of connections allows you to increase the speed and dynamic accuracy of the control system of the electromagnetic suspension of the rotor.

In FIG. 1 is a functional diagram of each channel of the rotor electromagnetic suspension control system; in FIG. 2 shows the connection of electromagnet windings to a power converter; in FIG. 3 is a structural diagram of one channel of a rotor electromagnetic suspension control system; in FIG. Figure 4 shows the graphs of transients in the control system of the electromagnetic suspension of the rotor.

Each channel of the control system (Fig. 1) contains a rotor position sensor 1, an integral controller 2, a proportional controller 3, a differentiating element 4, a proportional-differential controller 5, a power converter 6, two electromagnets 7 and 8, a reference unit 9, a proportional element 10 , subtraction blocks 11 and 12, sign extraction block 13, register 14, adder 15 and multiplexer 16. The rotor position sensor 1 is connected to the inverse inputs of integral 2 and proportional 3 regulators and the input of the differentiating link 4. The output is proportional controller 3 is connected to the direct input of the proportional-differential controller 5, the inverse input of which is connected to the output of the differentiating link 4. The output of the proportional-differential controller 5 is connected to the input of the power converter 6, the output of which is connected to the windings of the electromagnets 7 and 8. The first output of the task unit 9 connected to the input of the proportional link 10 and the first input of the subtraction unit 11. The output of the rotor position sensor 1 is connected to the second input of the subtraction unit 11, the output of which is connected to the input of the sign extraction unit 13. The output of the integral controller is connected to the first inputs 12 of the subtraction unit and register 14, the output of which is connected to the first input of the adder 15. The second output of the task unit 9 is connected to the first input of the multiplexer 16. The output of the proportional link 10 is connected to the second input of the adder 15, the output of which is connected to the second input of the multiplexer 16. The output of the sign extraction unit 13 is connected to the second input of the register 14 and the third input of the multiplexer 16, the output of which is connected to the second input of the subtraction unit 12. The output of the subtraction unit 12 is connected to the direct input of the proportional controller 3.

The integral regulator 2, the proportional regulator 3, the differentiating link 4, the proportional-differential regulator 5 and the proportional link 10 can be implemented, for example, by a.s. USSR No. 1649501, publ. 05/15/91, bull. No. 18. Parameter setting block 9 can be performed, for example, on K555TM8 microcircuits, the bit inputs of which are connected via switches to logical zeros or ones. The subtraction blocks 11 and 12 and the adder 15, for example, are made on K555IM6 microcircuits. The sign extraction unit 13 can be implemented, for example, in the form of a trigger connected to the high-order bit of the output of the subtraction unit 11. Register 14, for example, can be performed on K555TM8 microcircuits. The multiplexer 16 can be implemented, for example, on K555KP11 chips. The above blocks of the electromagnetic rotor suspension control system can also be performed programmatically on a microprocessor or programmable controller. As the sensor 1 of the position of the rotor can be applied, for example, an inductive eddy current sensor with a measurement unit, made, for example, according to the patent of the Russian Federation No. 2191346, publ. 10/20/2002, bull. No. 29. Power converter 6, for example, is a transistor pulse-width converter, consisting of a pulse-width modulator (see Russian patent No. 2172062, publ. 10.08.2001, bull. No. 22) and a transistor bridge. The electromagnets 7 and 8 are located on the stator of the rotor machine, for example, on the same axis on opposite sides of the rotor and can be performed, for example, as explicit pole or with distributed windings. The electromagnet windings are connected to a transistor bridge, for example, as shown in FIG. 2.

The control system of the electromagnetic suspension of the rotor operates as follows. In each control channel, the rotor position sensor 1 measures the deviation of the rotor from the central position, which is taken as zero. The signal about the measured deviation is fed to the inverse inputs of the integral and proportional controllers 2 and 3 and to the input of the differentiating link 4. In accordance with the transfer functions implemented by the regulators 2, 3 and 5, the differentiating link 4, the proportional link 10, blocks 11 and 12 of subtraction, by block 13 of the allocation of the sign, register 14, adder 15 and multiplexer 16, from the output of the proportional-differential controller 5 to the input of the power converter 6, a signal is proportional to which the power converter 6 is regulated uet voltage on the windings of the electromagnets 7 and 8. As a result of such currents are generated in the windings of the electromagnets 7 and 8, which creates a resultant force that returns the rotor to the center (Sensor 1) position.

- передаточная функция интегрального регулятора 2; k_П - коэффициент передачи пропорционального регулятора 3; k_OCC - коэффициент передачи (постоянная времени) дифференцирующего звена 4; W_ПД(p) - передаточная функция пропорционально-дифференциального регулятора 5; k_И - коэффициент передачи пропорционального звена 10; х_З(p), F_B(p) и х(р) - изображения сигналов задания, возмущающей силы и перемещения (отклонения от центрального положения) ротора, соответственно. Причем, для системы управления электромагнитным подвесом ротора принципиально х_З(p)=0. Δх₀ - величина рассогласования, задаваемая блоком 9 задания. х_И(-0) - значение выходного сигнала интегрального регулятора, фиксируемое регистром 14 в момент смены знака на выходе блока 11 вычитания. Блок 9 задания также формирует нулевой сигнал на соответствующем входе мультиплексора 16. Мультиплексор 16 представлен на структурной схеме переключателем, управляемым нелинейным звеном, представляющим собой блок 13 выделения знака.The processes occurring during the operation of the proposed control system for the electromagnetic suspension of the rotor can be represented by a structural diagram (Fig. 3). Here k _DP is the transfer coefficient of the position sensor 1; $$\frac{\mathrm{one}}{T_{\mathrm{and}}p}$$

- transfer function of the integral controller 2; k _P - gear ratio of the proportional controller 3; k _OCC is the transmission coefficient (time constant) of the differentiating element 4; W _PD (p) is the transfer function of the proportional differential controller 5; k _And - gear ratio of the proportional link 10; x ₃ (p), F _B (p) and x (p) are images of reference signals, disturbing force and displacement (deviation from the center position) of the rotor, respectively. Moreover, for the control system of the electromagnetic suspension of the rotor fundamentally x _W (p) = 0. Δx ₀ - the value of the mismatch specified by block 9 of the job. x _AND (-0) is the value of the output signal of the integral controller, fixed by the register 14 at the time of the sign change at the output of the subtraction unit 11. The task unit 9 also generates a zero signal at the corresponding input of the multiplexer 16. The multiplexer 16 is represented in the block diagram by a switch controlled by a non-linear link, which is a sign extraction unit 13.

The remaining dynamic links in the aggregate are a linearized mathematical model of the process of moving the rotor in the field of the electromagnetic bearing under the action of a control signal at the input of the power converter 6. The transmission coefficients k _PWM and U characterize the parameters of the power converter 6: the transmission coefficient of the pulse-width converter and the supply voltage of the transistor bridge .

(Т_Э - постоянная времени электрической цепи обмоток электромагнитов) связывает приращение соотношения токов в электромагнитах 7 и 8 с приращением напряжения на обмотках, причем заведомо принимается такой закон коммутации транзисторов моста, что увеличение напряжение на одной из обмоток приводит к такому же уменьшению напряжения на другой. Коэффициент передачи k_ЭМ связывает силу, действующую со стороны электромагнитов на ротор при его центральном положении, с соотношением токов в электромагнитах. Коэффициент передачи k_F характеризует изменение силы, действующей на ротор, при его отклонении от центрального положения. Динамическое звено $$\frac{1}{m{p}^2}$$

в соответствии со вторым законом Ньютона определяет перемещение ротора под действием результирующей силы. Коэффициент передачи k_E характеризует приращение наводимой в обмотках электромагнитов ЭДС со скоростью перемещения ротора в магнитном поле.Dynamic link with transfer function $$\frac{\mathrm{one}}{U(T_{E}R+\mathrm{one})}$$

(T _E is the time constant of the electric circuit of the electromagnet windings) relates the increment of the ratio of currents in electromagnets 7 and 8 to the increment of voltage on the windings, and the law of switching transistors of the bridge is obviously adopted such that an increase in voltage on one of the windings leads to the same decrease in voltage to the other . The transmission coefficient k _EM connects the force exerted by the electromagnets on the rotor with its central position, with the ratio of currents in the electromagnets. The gear coefficient k _F characterizes the change in the force acting on the rotor when it deviates from its central position. Dynamic link $$\frac{\mathrm{one}}{\mathrm{<figure-callout\; id="2"\; label="m\; p"\; filenames="00000008.png"\; state="\{\{state\}\}">m\; </figure-callout>}{p}^{}{}^2}$$

in accordance with the second law of Newton determines the movement of the rotor under the action of the resulting force. The transfer coefficient k _E characterizes the increment induced in the windings of the electromagnets EMF with the speed of movement of the rotor in a magnetic field.

The value of the time constant of the proportional differential controller 5

W _PD (p) = k _PD (T _PD p + 1)

determined, for example, from the relation

T _PD = 3T _E ,

and the transmission coefficient k _{PD of} this controller can vary widely. The values of the transfer coefficient k _{P of the} proportional controller 3 and the time constant T _{AND of the} integral controller 2 in accordance with the stability condition can also be selected from a wide range of values.

A feature of the proposed electromagnetic suspension control system is that at the moment of switching on, the output of the subtraction unit 12 contains a zero signal. In the process of the ascent of the rotor, the output signal of the subtraction unit 12 changes depending on the output signal of the integral controller 2. At the time when the mismatch at the input of the integral controller becomes equal or becomes less than Δx ₀ , the output signal of the allocation unit 13 changes its status, is recorded in register 14 the value of x _AND (-0) from the output of the integral controller 2. This value using the adder 15 is added to the product k _AND Δx ₀ . At the same time, the multiplexer 16 switches and passes to the input of the subtraction unit 12 the output signal of the adder 15, which at this moment has become equal to the sum of x _AND (-0) + k _AND Δx ₀ . As a result, at the output of the subtraction unit 12, at the time of switching the multiplexer 16, a signal equal to -k _AND Δx ₀ appears. A further change in the output signal of the subtraction unit 12 is determined only by the operation of the integral controller 2. The steps taken by the blocks 9-16 additionally introduced into the control system of the rotor electromagnetic suspension of the rotor allow achieving stable operation without changing the time constant T _{AND of the} integral controller 2 due to only a one-time adaptation of the output signal of this controller . The value of the coefficient k _{And the} transmission of the proportional link 10 can be selected, for example, from the relation

where k ₁ = k _PD k _PWM k _EM k _OCC k _DP , k ₂ = k _P k _PD k _PWM k _EM k _DP .

Computer simulation shows the achievable performance of the proposed rotor electromagnetic suspension control system.

Figure 4 shows graphs of transients during the ascent of the rotor from the safety bearings and under the action of a disturbing force at the initial central position of the rotor. In the calculations, the following parameters of the electromagnetic suspension of the rotor, for example, a turbine, were taken: k _E = 1461 Vs / m; k _EM = 1306 N; k _F = 1315900 N / m; m = 36 kg; T _e = 0.038233 s; k _PWM = 1.9608 · 10 ^-3 ; U = 57.7 V; k _PD = 8; T _PD = 0.115 s; k _P = 8; k _OSS = 0.0032 s; k _And = 0.843; T _And = 0.0032 s; k _DP = 1,000,000 discrete / m; Δx ₀ = 250 discret.

Analysis of the graphs shows that in the control system of the electromagnetic suspension of the rotor there is a high speed in all operating modes. The rotor emerges from the safety bearings having a clearance in the working state δ = 0.5 mm, for a time t _PP = 0.03 s. The dynamic failure of the rotor with an impact force of 1 N is Δx _max = 0.002 μm. It should also be noted that the rotor returns to its center position after application of the load. To achieve such speed in the control system, taken as a prototype, it is impossible.

Thus, the proposed control system allows to increase the speed and dynamic accuracy of the electromagnetic suspension of the rotor.

Claims (1)

The control system of the rotor electromagnetic suspension, each channel of which contains a rotor position sensor, an integral regulator, a proportional regulator, a differentiating element, a proportional-differential regulator, a power converter, two electromagnets, the rotor position sensor output being connected to the inverse inputs of the integral and proportional regulators and the differential input link, the output of the proportional controller is connected to the direct input of the proportional differential controller, inv whose input is connected to the output of the differentiating link, the output of the proportional-differential controller is connected to the input of the power converter, the output of which is connected to the windings of electromagnets, characterized in that each channel is additionally equipped with a reference unit, a proportional link, the first and second subtraction blocks, a sign extraction unit , register, adder and multiplexer, and the first output of the job block is connected to the input of the proportional link and the first input of the first subtraction block, the output of dates the rotor position sensor is connected to the second input of the first subtraction unit, the output of which is connected to the input of the sign extraction unit, the output of the integral controller is connected to the first inputs of the second subtraction and register block, the output of which is connected to the first input of the adder, the second output of the task unit is connected to the first input of the multiplexer , the output of the proportional link is connected to the second input of the adder, the output of which is connected to the second input of the multiplexer, the output of the sign extraction unit is connected to the second input of the register and the third input m multiplexer whose output is connected to a second input of the second subtracting unit, and a second subtracter output is connected to the direct input of the proportional regulator.

Images