SU1701990A1 - Method and apparatus for controlling output of electric compressor - Google Patents

Abstract

1. A method of controlling the performance of an electrically driven compressor by varying the pressure and gas flow rate at the outlet of the compressor, determining the measured values of control power by changing the position of the throttle valve and control power by changing the frequency of rotation of the rotor of the compressor, comparing the obtained power and changing the frequency of rotation of the rotor

Description

This invention relates to compressor control.

The aim of the invention is to increase the reliability of the operation of the compressor at modes close to surge.

The drawing shows the block diagram of the device that implements this method.

A device for controlling the performance of compressor 1 with electric drive 2 contains a sensor 3 for gas flow rate at the compressor outlet, a first functional converter 4, a block 5 for controlling the frequency of rotation of the electric drive, a block 6 for controlling the throttle valve, a sensor 7 for gas pressure at the outlet of the compressor, the first block multiplying 8 , the second functional converter 9, the first comparator 10, the third functional converter 11, the fourth functional converter 12, the setting device 13, the second multiplication unit 14 and the second one comparator 15.

In addition, the drawing shows contactors 16 to 18. Synchronizer 19, frequency converter 20, inverter controller 21, rectifier controller 22, frequency lock 23, converter current sensor 24, nonlinear element 25. converter model 26 and switch 27. input Units in control unit 5 of the frequency of rotation of the drive.

The method is implemented as follows.

When the drive 2 of the compressor 1 from the mains sensor signals

3 and 7, the flow rate and pressure of the gas at the outlet of the compressor go to the first multiplication unit 8, the output of which produces a signal proportional to the hydraulic power of the compressor N. At the same time, the signal from the gas flow sensor 3 is fed to the inputs of the first and third function transducers 4 and 11. at the outputs which form signals proportional to

v + v / a o T fFTirH 7T n

n aQ2 + bQ + s

where Q is the gas flow rate at the outlet of the compressor;

n - compressor efficiency: a, b, c, d, h, H, f - coefficients, v - rotation frequency of the compressor rotor.

The signals from the output of the first multiplication unit 8 and the third functional converter 11 are fed to the second functional converter 9, the output of which produces a signal proportional to the power consumed by the electric actuator 2 under throttling Pi Pi.

1 n 0.97

From the output of the first functional converter 4, the signal enters the latch 23 of the frequency of the control unit 5, providing the required rotational speed of the compressor rotor. In addition, from the output of the first functional converter

4, the signal is fed to the fourth functional converter 12, at the output of which a signal is generated that is proportional to the P2 power consumed by the drive from the network depending on the rotational frequency

P2 Kv2, where K is a coefficient.

Signals proportional to the powers PI and P2 arrive at the first comparator 10, where they are compared. At P2 Pi, a relay signal is generated at the comparator output, arriving at block 5, disconnecting the contactor 16 and turning on the contactors 17 and 18, resulting in a change in performance by varying the frequency of rotation of the electric drive by acting on the frequency converter 20 with current control and operating time. transducer using 24 current sensor of nonlinear element 25, converter model 26 and switch 27.

At P2, the PI signal at the output of the first comparator disappears, the actuator 2 is connected to the network, the mine is transformed

A frequency is fed, while the throttle control unit 6 receives a control signal, thereby realizing the performance control by changing the position of the throttle valve.

At the same time, the signal from the gas flow sensor 3 at the compressor output goes to the second comparator 15, to another input of which a signal is output from the second multiplication unit, proportional to the limiting flow rate value obtained by multiplying the signal of the setpoint 13 by the output signal of the first functional converter 4

Qi f -v, where Qi is the limit value of the flow,

f - coefficient.

When the current Q QoO Qi value decreases, the second comparator 15 operates and generates a surge signal, which is fed to the alarm and protection elements (for example, block 5 in order to open the throttle valve and increase the compressor rotor speed)

Claims (2)

1. The method of regulating the performance of the compressor with electric drive by changing the pressure and gas flow rate at the outlet of the compressor, determining the measured power of the regulation by changing the throttle position and the power of regulation by changing the rotor speed of the compressor, comparing the obtained power and changing the rotor speed Ό ΙνΟόόΙΟΖΙ 3 1701990 four of the compressor and the position of the throttle valve according to the results of the comparison ^ t l and c with the fact that, in order to increase the reliability of the compressor operation at modes close to surging, additionally by the measured value of the gas flow rate at the compressor outlet, the maximum permissible gas flow rate is determined, compare the obtained and measured values, and when the maximum permissible measured value of the gas flow is exceeded, a surge signal is generated. 2. A device for controlling the performance of the compressor by an electric actuator, comprising a series-connected gas flow sensor at the compressor outlet, a first functional converter, an electric drive speed control unit and a throttle valve control unit connected in series with the gas pressure sensor at the output of compressor, the first multiplication unit, the second functional converter and the first comparator, as well as the third and fourth functional converters connected by inputs to the gas flow sensor and the first functional converter, respectively, and the outputs to the second inputs of the second functional converter and the first comparator, respectively, the latter is connected to the frequency control unit, the second input of the first multiplication unit is connected to the flow sensor, and the second output of the frequency control unit It is compatible with the electric drive of the compressor, characterized in that it further comprises a serially connected unit, a second multiplication unit and a second comparator connected by a second input to the flow sensor, with the second input of the second multiplication unit connected to the first functional converter.