RU2011287C1 - D c electric motor drive - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: in given D. C. electric motor drive reduction of power losses is obtained by insertion of signal proportional to rotational speed into system of nonlinear conversion which takes into account consumption of reactive power. EFFECT: expanded application field in industrial mechanisms. 1 dwg

Description

 The invention relates to electrical engineering.

 The known electric drive [1] contains a series-connected rectifier, current sensor, electric motor, tachogenerator, a converter in the field circuit and a nonlinear converter.

 The disadvantage of this device is the relatively low efficiency.

 The closest in technical essence and the achieved results is a direct current electric drive [2], containing an electric motor connected to a thyristor rectifier, setpoint units connected in series, a speed controller and a current controller, the output of which is connected to the input of a thyristor rectifier, current and speed sensors, the outputs of which are connected to the feedback inputs of the current controller and speed controller, respectively, the pathogen, the output of which is connected to the outputs of the winding uzhdeniya motor.

 The disadvantage of this device is the relatively large energy losses, since it does not take into account the energy losses in the network and, above all, losses caused by the consumption of reactive power.

 The purpose of the invention is to reduce energy loss.

, где ω- частота вращения;
a, b, d - константы;
ω_о - частота вращения идеального холостого хода.The goal is achieved due to the fact that an adder is introduced into the electric drive, the output of which is connected to the exciter’s input, an exposure unit to the fourth degree, a quadrator, a flow sensor and three multipliers, the output of the first and second of which are connected directly to the inputs of the adder, and the third through a quadrator, the first input of the first multiplier is connected to the output of the fourth degree block, the input of which is connected to the current sensor, the first inputs of which and the third multiplier are connected to the output of the flow sensor and the input of the block the fourth degree, the second input of the third multiplier is connected to the output of the current sensor, the second inputs of the first and second multipliers coupled respectively through first and second function generators to the input speed sensor, said first and second function generators respectively implement the following functional relationships
U ₁ = a + b ω ^d ;
U ₂ =

where ω is the rotation frequency;
a, b, d are constants;
ω _about - ideal idle speed.

 Significant differences of the proposed technical solution are that it takes into account the loss component associated with the flow of reactive power in the network. As you know, the energy loss in the network is proportional to reactive power. This proposal takes into account this component of energy.

 The drawing shows a diagram of the device.

 Motor 1, sensor 2, thyristor rectifier 3, current controller 4, frequency controller 5 and setpoint unit 6 are connected in series. The flow sensor 7 is installed next to the field winding 8. The tachogenerator 9 is connected to the frequency controller 5, the first 10 and the second 11 functional converters, which are connected through the multipliers 12, 13 to the adder 14. The multiplier 15 through the quadrator 16 connects the output of the tachogenerator 9 and the flow sensor 17 with the input of the adder 14. The output of the latter is connected with the exciter 17 connected by the output to the field winding 8. The flow sensor 7 is also connected to the block 18 raising to the 4th degree.

 The device operates as follows.

 Engine 1 operates at an adjustable speed. Frequency control is carried out by changing the setpoint signal received from the output of block 6. Regulator 5 compares this signal with the actual frequency value coming from the output of the tachogenerator 9 and generates a regulatory effect on the frequency stabilization. This signal through the controller 4 is fed to the control of a thyristor rectifier 3, which changes the value of the armature voltage. This control channel (frequency) has a high speed. Along with this, there is a second excitation control channel. This channel has significantly lower speed (an order of magnitude). Therefore, the operation of this channel is manifested mainly in steady-state modes.

 The amplifier 14 sets the voltage value of the exciter 17, at which the drive operates with minimal loss of electricity. For this, the adder 14 has integral properties (such as a PI or AND controller).

 We show the conditions under which a minimum of energy loss is achieved.

+ C

f(ω)U

и постоянные потери энергии
ΔP₂= aΦ²+bω^dΦ²+K_Mωⁿ, где R - сопротивление якорной цепи;
М, Φ, ω- момент, поток и частота вращения двигателя;
С - коэффициент перевода реактивной мощнсти в потери энергии (С≈0,1-0,3 кВт/кВар);
b - коэффициент потерь в стали;
d= 1,2-1,5;
n - коэффициент механических потерь,
n≈1-1,5, a = R

Здесь R_B - сопротивление обмотки возбуждения;

- тангенс наклона характеристики намагничивания;
f(ω) - зависимость относительной реактивной составляющей тока от напряжения якоря или что практически тоже от скорости.Variable energy loss [2]
ΔP ₁ = R

+ C

f (ω) U

and constant energy loss
ΔP ₂ = aΦ ² + bω ^d Φ ² + K _M ω ⁿ , where R is the resistance of the anchor chain;
M, Φ, ω- moment, flow and engine speed;
C is the conversion factor of reactive power into energy loss (C≈0.1-0.3 kW / kVar);
b is the loss coefficient in steel;
d = 1.2-1.5;
n is the coefficient of mechanical loss,
n≈1-1.5, a = R

Here R _B is the resistance of the field winding;

- the slope of the magnetization characteristic;
f (ω) is the dependence of the relative reactive component of the current on the voltage of the armature or, practically, also on speed.

- максимальное напряжение выпрямителя;
ω_о - скорость идеального холостого хода двигателя при U

.U

- maximum voltage of the rectifier;
ω _о - ideal idle speed of the engine at U

.

+

= 1
Минимум потерь достигается при

, что достигается при
условии Φ⁴(a+bω^d)-

-RM²= 0
. На выходе преобразователей 10 и 11 формируются сигналы U₁= a+ bω^d и U₂=

соответственно. Усилитель 14 осуществляет решение последнего уравнения. В случае отклонения упомянутого равенства от нуля на выходе усилителя 14 появляется сигнал, который изменяет значение потока в сторону, вызывающую исчезновение неравенства нулю суммы входных сигналов. Таким образом благодаря нелинейному преобразованию сигнала в блоке 11, пропорционального напряжения или что тоже частоте вращения учитывается потребление реакционной мощности и связанные с ней потери энергии в сети. Благодаря этому снижаются суммарные потери энергии. (56) 1. Ильинский Н. Ф. и др. Энергосбережение в электроприводе. М. : Высшая школа, 1989, с. 90, рис. 81.For example, for a symmetrical controlled rectifier
f

+

= 1
The minimum loss is achieved when

what is achieved when
condition Φ ⁴ (a + bω ^d ) -

-RM ² = 0
. At the output of the converters 10 and 11, signals U ₁ = a + bω ^d and U ₂ =

respectively. Amplifier 14 solves the last equation. In the case of a deviation of the said equality from zero at the output of the amplifier 14, a signal appears that changes the value of the flow to the side, causing the disappearance of the inequality to zero of the sum of the input signals. Thus, due to the nonlinear conversion of the signal in block 11, proportional to the voltage, or even to the rotational speed, the consumption of reaction power and the associated energy loss in the network are taken into account. Due to this, the total energy loss is reduced. (56) 1. Ilyinsky N. F. et al. Energy Saving in an Electric Drive. M.: High School, 1989, p. 90, fig. 81.

 2. Lebedev E. D. Control of valve DC electric drives. M.: Energy, 1980, p. 97. Fig. 42.

Claims (1)

A DC electric drive containing an electric motor connected to a thyristor rectifier, a setpoint unit connected in series, a speed controller and a current controller, the output of which is connected to the input of a thyristor rectifier, current and speed sensors, the outputs of which are connected to the feedback inputs of the current controller and controller frequency of rotation, the pathogen, the output of which is connected to the terminals of the field winding of the electric motor, characterized in that, in order to increase the efficiency, input we have an adder whose output is connected to the exciter input, a fourth degree block, a quadrator, a flow sensor, and three multipliers, the outputs of the first and second of which are connected directly to the inputs of the adder, and the third through a quadrator, the first input of the first multiplier is connected to the output of the block fourth degree expansion, the input of which is connected to the flow sensor, the first inputs of the second and third multipliers are connected to the output of the flow sensor and the input of the fourth degree block, the second input of the third soybean multiplier dinene with the output of the current sensor, the second inputs of the first and second multipliers are connected through the first and second functional converters respectively to the input of the speed sensor, and the first and second functional converters respectively implement the following functional dependencies:
U _f.p1 = a + b ω ^c ,
U

=

,
where ω is the rotation frequency;
a, b, c are constants;
ω ₀ - ideal idle speed.

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