RU2168119C2 - Medium parameters controller - Google Patents

Abstract

FIELD: air-conditioning systems. SUBSTANCE: device has temperature and relative humidity transducers and setters, regulators consisting of comparison elements and transducer amplifiers, and actuating mechanisms with adjusting controls located in the heat-transfer agent supply lines and a sprinkling chamber. Introduction in the device of series-connected discrete differentiators with a storage, whose inputs are connected to the respective comparison elements, and feedback units containing logical elements, quick-operating relays and delayed relays, whose outputs are connected to the respective regulator units makes it possible to follow the variation of the setting, reduce the fluctuations of transients in the conditions of tracing of the setting, reduce the duration of transients, partially compensating for considerable sluggishness properties of the controlled object. EFFECT: enhanced quality of control. 1 dwg

Description

 The invention relates to the field of environmental control, for example, in air conditioning systems.

 A device for regulating the parameters of air conditioning [1, 2], containing sensors and controllers of temperature and relative humidity, is connected to the corresponding regulators, consisting of comparison elements and amplifier-converting units, and actuators with regulating bodies located on the coolant supply line and irrigation chambers.

 The disadvantages of the known device are the low quality of regulation (the duration of the transient process and significant fluctuations of the regulated values) due to the large inertia of the control object and the need for frequent changes in the task of adjustable parameters.

 The objective of the invention is to increase the speed and reduce the oscillation of transients of controlled values. The result is achieved by the fact that the device for regulating environmental parameters in air conditioning systems contains sensors and adjusters of temperature and relative humidity, regulators, consisting of comparison elements and amplifiers-converters, actuators with regulating bodies installed respectively on the coolant supply line and the irrigation chamber, equipped with sequentially connected discrete differentiators with memory, the inputs of which are connected to the corresponding elements and comparisons, and feedback blocks containing logic elements, high-speed relays and relays with a delayed response, the outputs of which are connected to the corresponding amplifier-converting blocks of the regulators.

 The existing technical solutions for regulating the environmental parameters did not use discrete memory differentiators connected to feedback blocks containing logic elements, high-speed relays with a slowdown in response to the proposed combination with previously known blocks, which gives a new positive effect, namely, it improves the quality of regulation (decrease in duration and decrease in the oscillation of transients).

 The drawing shows a structural diagram of the proposed device for controlling environmental parameters in air conditioning systems.

 The device contains: an object of regulation - room 1; sensors: respectively - air temperature 2 and relative humidity 3; adjusters: respectively - air temperature 4 and relative humidity 5; regulators: respectively - air temperature 10 and relative humidity 11, containing comparison elements 6, 7 and amplifier-converting blocks 8, 9; discrete differentiators with memory 12, 13; feedback blocks 20, 21, containing logic elements 14, 15, high-speed relays 16, 17, relays with a delay in operation 18.19; actuators with regulatory bodies 22, 23 installed on the coolant supply line and the irrigation chamber.

 We will consider the operation of the device using the example of stabilization of air temperature in a room. Stabilization of relative humidity is carried out similarly.

 The signal from the temperature sensor 2, proportional to the current value of the air temperature in the room, and the signal from the setter 4, proportional to the currently set value of the air temperature, are sent to the comparison element 6 of the air temperature controller 10, where these two values are compared and their difference is determined, those.

ε (t) = x (t) - x ₀ , (1)
where x (t) is the current temperature value taken from sensor 2;
x ₀ - the signal of the driving action, taken from the setpoint value of the adjustable parameter 4;
ε (t) is the error signal.

 The mismatch signal ε (t) obtained on the comparison element 6 of the controller 10 is fed to the input of the amplifier-transforming unit 8 of the controller 10, where it is amplified and, in accordance with the selected control algorithm (proportional, proportional-integral, or proportional-integral-differential), the control signal z entering the actuator with a regulating body 22 located on the coolant supply line, changing the coolant supply so as to reduce the amount of mismatch ε (t). This is how the device for controlling environmental parameters works, selected as a prototype.

 The proposed device operates as follows. The mismatch signal ε (t) from the comparison element 6 of the controller 10 is fed simultaneously to the discrete differentiator with a memory of 12, which compares with the mismatch ε (tT) stored by the discrete differentiator at the previous controller response time, where T is the repetition period of the pulse control signal z of controller 10. At the same time, a new mismatch value ε (t) is stored instead of ε (tT) in the memory cells of the discrete differentiator with memory 12.

In the discrete differentiator with memory 12, an auxiliary control signal is generated
z ₁ (t) = [ε (t) -ε (tT)] + ε (t), (2)
Let us consider expression (2) in more detail. The first two terms of the right-hand side of expression (2) are an approximate signal of the derivative of the signal ε (t), and the third term is the signal of the mismatch module ε (t).

 The output signal of block 12 consists of the sum of the approximate value of the derivative of the mismatch signal ε (t) and the modulus of the mismatch value ε (t).

The signal z ₁ (t) from the discrete differentiator with memory 12 is supplied to the logic element 14 of the feedback block 20. Depending on the sign z ₁ (t), the logic element 14 of the feedback block 20 switches the parameters of the block 20 to the state of forced or moderate regulation, in accordance with which the latter gives a feedback signal z _about (t) of one or another intensity to the amplifier-converting unit 8 of the controller 10.

где

- приближенное значение производной сигнала ε(t). На логический элемент 14 величина z₁(t) может поступать с дискретного дифференциатора с запоминанием 12 в четырех видах:
- производная возрастает, модуль возрастает;
- производная убывает, модуль возрастает;
- производная убывает, модуль убывает;
- производная возрастает, модуль убывает.Consider in more detail the operation of the feedback unit 20. Rewrite the expression (2) in the following form

Where

is the approximate value of the derivative of the signal ε (t). On the logic element 14, the value z ₁ (t) can come from a discrete differentiator with a memory of 12 in four forms:
- the derivative increases, the modulus increases;
- the derivative decreases, the modulus increases;
- the derivative decreases, the module decreases;
- the derivative increases, the module decreases.

(t) и модуля величины ε(t).The logic element 14 of the feedback block 20 in the first two cases will send the signal z ₁ (t) to the high-speed relay 16, in the third and fourth cases - to the relay with a delay in operation 18. Thus, from the feedback block 20 an additional control signal z _about (t) enter the amplifier-converter unit 8 of the controller 10, where it will have its corrective effect on the quantity ε (t) received from the comparison element 6 on the amplifier-converter unit 8, depending on the size and sign of the derivative

(t) and the modulus of ε (t).

If the task x _{0 of the} control parameter in the time interval between pulses T does not change, or changes very little, then the difference between ε (t) and ε (tT) will be small, and the value of the additional signal coming from the feedback block 20 to the amplifying block 8 of the controller 10 will also be small, i.e. in practice, we can assume that ε (t) = ε (tT). This value of the mismatch appears at the time of the steady-state value of the controlled variable equal to the specified value of the controlled variable.

If during the transient at the time between the pulses T, the difference between ε (t) and ε (tT) will be significantly different from zero, then in the feedback block 20 using the high-speed relay 16, an additional signal z _ob (t) is generated, arriving at the input of the amplifier-converting unit 8 of the controller 10, which compensates for the significant inertia of the control object, reduces the transition process and smoothes the fluctuations of the adjustable value.

 If, at the time between the pulses T, a preset value of the controlled variable changes, then the difference between ε (t) and ε (t) will be significant and the role of the feedback unit will increase even more to accelerate the transition process and the controlled variable reaches a new preset value.

Moderate regulation, i.e., the inclusion of feedback relay block 20 by logic element 14 of the relay with a deceleration of 18 will be in the case if the derivative increases or decreases, and the mismatch module decreases, and the relay with a deceleration of operation allows you to avoid transient oscillations due to additional feedback signal z _о (t) to the amplifier-transforming unit of the controller. This mode of operation of the device is observed closer to the end of the transition process.

 The introduction of a discrete differentiator with memory and a feedback block containing a logic element, a high-speed relay and a relay with a delayed response into the device for controlling the parameters of the air conditioning environment makes it possible to monitor the change in the task, reduce the oscillation of transients in the tracking mode, change the task, reduce the duration of the transition modes, partially compensating for the significant inertial properties of the control object, and thereby ensure high quality of the control ligation.

Sources of information
1. Halameiser MB Automatic installations of artificial climate. M.: Mechanical Engineering, 1969, p. 139.

 2. Nefelov S. V., Davydov Yu.S. The technique of automatic regulation in ventilation and air conditioning systems. M .: Stroyizdat, 1984, p. 22 - 40.

Claims (1)

 A device for controlling environmental parameters, containing sensors and temperature and relative humidity sensors, regulators, consisting of comparison elements and amplifiers-converters, and actuators with regulatory bodies located on the supply lines of the coolant and the irrigation chamber, characterized in that it is equipped with series-connected discrete differentiators with memory, the inputs of which are connected to the corresponding elements of comparison, and feedback blocks containing logical elements, high-speed relays and relays with a deceleration on response, the outputs of which are connected to the corresponding amplifying and converting blocks of the regulators.