阅读说明：本技术 一种空压机的两级压缩控制方法、控制器和空压机 (Two-stage compression control method and controller of air compressor and air compressor ) 是由 陈欣佩 卢衍林 韩文翰 于 2020-06-11 设计创作，主要内容包括：一种空压机的两级压缩控制方法、控制器和空压机,空压机启动时,检测二级主机排气口的压力值,若该压力值小于设定的目标压力值,则提高一级电机的转速,若压力值大于设定的目标值则降低一级电机的转速,直至相等,同时,根据预设的转速比控制二级电机的转速；空压机正常运行时,采用PID控制方法调整该转速比,具有高效、可靠、性价比高的优点。(A two-stage compression control method of an air compressor, a controller and the air compressor are provided, when the air compressor is started, a pressure value of an exhaust port of a secondary host is detected, if the pressure value is smaller than a set target pressure value, the rotating speed of a primary motor is increased, if the pressure value is larger than the set target value, the rotating speed of the primary motor is reduced until the pressure value is equal to the set target value, and meanwhile, the rotating speed of the secondary motor is controlled according to a preset rotating speed ratio; when the air compressor normally operates, the rotating speed ratio is adjusted by adopting a PID control method, and the air compressor has the advantages of high efficiency, reliability and high cost performance.)

1. A two-stage compression control method of an air compressor is characterized in that: when the air compressor is started, detecting the pressure value of the exhaust port of the secondary host, if the pressure value is smaller than a set target pressure value, increasing the rotating speed of the primary motor, if the pressure value is larger than the set target value, reducing the rotating speed of the primary motor until the pressure value is equal to the set target value, and simultaneously controlling the rotating speed of the secondary motor according to a preset rotating speed ratio; when the air compressor normally operates, the rotating speed ratio is adjusted by adopting a PID control method.

2. The two-stage compression control method of the air compressor as claimed in claim 1, wherein: the rotation speed ratio is the rotation speed of the secondary motor/the rotation speed of the primary motor.

3. The two-stage compression control method of the air compressor as claimed in claim 1, wherein: the PID control method has the calculation formula as follows:

u(k)＝(Kp*e(k)²)+Ki*T*∑e(i)+(Kd/T)*[Pv(k)–Pv(k-1)]

wherein: u (k) is the output value of the current rotating speed ratio, e (k) is the current deviation, Σ e (i) is the accumulated steady-state error, sv (k) is the current set target pressure value, Pv (k) is the current feedback pressure value, Pv (k-1) is the previous feedback pressure value, T is the sampling time, Kp is the proportional gain, Ki is the integral gain, and Kd is the differential gain.

4. The two-stage compression control method of the air compressor as claimed in claim 3, wherein: the differential gain Kp is determined according to the current deviation, specifically:

e(k)≥5 kp＝100

1≤e(k)≤5 kp＝50

0.2≤e(k)＜1 kp＝5

5. the two-stage compression control method of the air compressor as claimed in claim 3, wherein: for the current deviation e (k), the values are set as follows: e (k) ═ sv (k) — pv (k); when the direction is reversed: e (k) ═ pv (k) — sv (k).

6. The two-stage compression control method of the air compressor as claimed in claim 1, wherein: when the air compressor normally operates, the relationship between the pressure of the first-stage exhaust and the pressure of the second-stage exhaust is set to satisfy:

P1＝((P2+1)^0.5)-1

wherein: p1 is the pressure value of the primary exhaust gas, and P2 is the pressure value of the secondary exhaust gas.

7. The utility model provides a two-stage compression controller of air compressor machine which characterized in that: the two-stage compression control method of the air compressor of any one of claims 1 to 6 is adopted.

8. The utility model provides an air compressor machine which characterized in that: a two-stage compression controller for an air compressor having the compressor of claim 7.

9. The air compressor as claimed in claim 8, wherein: and a double-permanent magnet driving double-compression main machine is adopted.

Technical Field

The invention relates to the field of air compressors, in particular to a two-stage compression control method, a controller and an air compressor.

Background

With the continuous development of the technology, the stability requirement of the air-using equipment on the air compressor is higher and higher, the efficiency requirement on the air compressor is higher and higher, and the air compressor of the secondary compression is favored by customers more and more.

At present, two stages of compression air compressors are roughly provided with two schemes,

scheme 1: one motor drives 2 main machines, the motor drives a primary compression main machine and a secondary compression main machine through gears, and the relative rotating speed of the primary compression main machine and the secondary compression main machine cannot be adjusted in the process of fixed operation of the gear teeth. By adopting the scheme, 3 gears and one gear box need to be contained through gear transmission, the whole manufacturing cost is high, and the relative rotation speed of the first stage and the second stage cannot be adjusted in the operation process. The first stage exhaust pressure is not adjustable, and the efficiency is poor.

Scheme 2: two motors drive 2 main machines, the two motors respectively drive the primary main machine and the secondary main machine in a coaxial/direct connection transmission mode, and the relative rotating speed of the primary main machine and the secondary main machine is controlled by PID (proportion integration differentiation), so that the loads of the primary main machine and the secondary main machine are consistent. By adopting the scheme, the PID is controlled only by the PID, and the rotating speed of the secondary motor does not accord with the required rotating speed in the starting process due to the untimely PID adjustment, so that the primary exhaust pressure is too high, and further faults are reported.

Disclosure of Invention

The invention mainly aims to overcome the defects in the prior art, provides a two-stage compression control method, a controller and an air compressor, and has the advantages of high efficiency, reliability and high cost performance.

The invention adopts the following technical scheme:

a two-stage compression control method of an air compressor is characterized in that: when the air compressor is started, detecting the pressure value of the exhaust port of the secondary host, if the pressure value is smaller than a set target pressure value, increasing the rotating speed of the primary motor, if the pressure value is larger than the set target value, reducing the rotating speed of the primary motor until the pressure value is equal to the set target value, and simultaneously controlling the rotating speed of the secondary motor according to a preset rotating speed ratio; when the air compressor normally operates, the rotating speed ratio is adjusted by adopting a PID control method.

Preferably, the rotation speed ratio is the rotation speed of the secondary motor/the rotation speed of the primary motor.

Preferably, the calculation formula of the PID control method is:

u(k)＝(Kp*e(k)²)+Ki*T*∑e(i)+(Kd/T)*[Pv(k)–Pv(k-1)]

wherein: u (k) is the output value of the current rotating speed ratio, e (k) is the current deviation, Σ e (i) is the accumulated steady-state error, sv (k) is the current set target pressure value, Pv (k) is the current feedback pressure value, Pv (k-1) is the previous feedback pressure value, T is the sampling time, Kp is the proportional gain, Ki is the integral gain, and Kd is the differential gain.

Preferably, the differential gain Kp is determined according to the current deviation, specifically:

e(k)≥5kp＝100

1≤e(k)≤5kp＝50

0.2≤e(k)＜1kp＝5

preferably, for the current deviation e (k), the values are set as follows in the forward direction: e (k) ═ sv (k) — pv (k); when the direction is reversed: e (k) ═ pv (k) — sv (k).

Preferably, when the air compressor operates normally, the pressure relation between the primary exhaust pressure and the secondary exhaust pressure is set to satisfy:

P1＝((P2+1)^0.5)-1

wherein: p1 is the pressure value of the primary exhaust gas, and P2 is the pressure value of the secondary exhaust gas.

The utility model provides a two-stage compression controller of air compressor machine which characterized in that: the two-stage compression control method of the air compressor is adopted.

The utility model provides an air compressor machine which characterized in that: have the two-stage compression controller of an air compressor machine of foretell.

Preferably, a double-permanent magnet is adopted to drive a double-compression main machine.

As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following advantages:

1. according to the method, in the starting process of the air compressor, the rotating speed of the primary motor is adjusted according to the comparison structure of the pressure value of the exhaust port of the secondary host and the target pressure value, the rotating speed of the secondary motor is controlled through the preset rotating speed ratio, the problem that the rotating speed of the secondary motor does not accord with the required rotating speed, and the primary exhaust pressure is too high is avoided, and the method has the advantages of high efficiency, reliability and high cost performance.

2. According to the method, in the operation process of the air compressor, the pressure of the primary exhaust and the pressure of the secondary exhaust meet the preset relation, the pressure of the primary exhaust can be adjusted, and the working efficiency is improved.

3. According to the air compressor, the primary motor and the secondary motor are adopted to respectively control the primary main machine and the secondary main machine, so that a gear transmission structure is saved, the size is reduced, and the cost is reduced.

Drawings

Fig. 1 is a flowchart of the air compressor of the present invention when starting.

The invention is described in further detail below with reference to the figures and specific examples.

Detailed Description

The invention is further described below by means of specific embodiments.

Referring to fig. 1, a two-stage compression control method of an air compressor detects a pressure value of an exhaust port of a secondary host when the air compressor is started, increases the rotation speed of a primary motor if the pressure value is smaller than a set target pressure value, decreases the rotation speed of the primary motor until the pressure value is equal to the set target value, and controls the rotation speed of the secondary motor according to a preset rotation speed ratio; and when the air compressor normally operates, the rotating speed ratio is adjusted by adopting a PID control method.

When the motor is started, the rotating speed of the primary motor is adjusted by adopting a PID control method, namely, the pressure value of the exhaust port of the secondary host is detected, if the pressure value is smaller than a set target pressure value, the rotating speed of the primary motor is increased, and if the pressure value is larger than the set target value, the rotating speed of the primary motor is reduced until the pressure value is equal to the set target value.

Wherein, the rotating speed ratio is the rotating speed of the secondary motor/the rotating speed of the primary motor. And when the air compressor is started, controlling the rotating speed of the secondary motor according to a preset rotating speed ratio. For example, when the rotation speed ratio is set to 2, the primary motor rotation speed is 1000 revolutions, the secondary motor rotation speed is 2000 revolutions, and so on. The rotating speed of the first-stage motor is increased or reduced, and the increasing or reducing numerical value is not limited and can be preset according to needs.

The preset rotation speed ratio is effective only in the starting process of the air compressor, and the preset rotation speed ratio is invalid after the starting process (or the stopping process) is finished. When the air compressor normally operates, the rotating speed of the primary motor is adjusted according to the secondary exhaust pressure, namely the rotating speed is the same as that during starting, the rotating speed of the secondary is the primary rotating speed and the rotating speed ratio, the rotating speed ratio is adjusted by adopting a PID control method, and the rotating speed ratio is automatically adjusted according to the actual condition.

The specific calculation formula of the PID control method is as follows:

u(k)＝(Kp*e(k)2)+Ki*T*∑e(i)+(Kd/T)*[Pv(k)–Pv(k-1)]

wherein: u (k) is the output value of the current rotating speed ratio, e (k) is the current deviation, Σ e (i) is the accumulated steady-state error, sv (k) is the current set target pressure value, Pv (k) is the current feedback pressure value, Pv (k-1) is the previous feedback pressure value, T is the sampling time, Kp is the proportional gain, Ki is the integral gain, and Kd is the differential gain.

The differential gain Kp is determined according to the current deviation, and specifically includes:

e(k)≥5kp＝100

1≥e(k)≤5kp＝50

0.2≤e(k)＜1kp＝5

for the current deviation e (k), which is a difference value between the currently set target pressure value and the currently fed back pressure value, specifically, when the value is set to be the forward direction: e (k) ═ sv (k) — pv (k); when the direction is reversed: e (k) ═ pv (k) — sv (k).

Further, e (i) is a steady state error value each time, Σ e (i) is an accumulated steady state error value, and the error value is a steady state error between a target pressure value set at the time of operation and a currently fed back pressure value, and is determined by an error in actual operation.

In addition, after the starting process is finished, in order to enable the pressure of the first-stage exhaust gas to meet the required pressure when the air compressor normally operates, the pressure relation between the pressure of the first-stage exhaust gas and the pressure of the second-stage exhaust gas is set to satisfy the following conditions:

P1＝((P2+1)^0.5)-1

wherein: p1 is the pressure value of the primary exhaust gas, and P2 is the pressure value of the secondary exhaust gas. The pressure values are gauge pressures in bar.

The invention further provides a two-stage compression controller of the air compressor, and the two-stage compression control method of the air compressor is adopted to control the rotation speed ratio of the first-stage motor and the second-stage motor.

The invention further provides an air compressor, and the two-stage compression controller of the air compressor is provided. The two-stage compression controller is connected with the first-stage host and the second-stage host and is used for controlling the rotating speed ratio of the two-stage compression control method.

In practical application, the air compressor of the invention can adopt double permanent magnet to drive double compression main machines, namely a primary motor and a secondary motor adopt permanent magnet motors, but the invention is not limited to the permanent magnet motors.

Referring to fig. 1, the working principle of the air compressor of the present invention is as follows:

when the air compressor is started, detecting the pressure value of the secondary host exhaust port, and if the pressure value is smaller than a set target pressure value, increasing the rotating speed of the primary motor; if the pressure value is larger than the set target value, reducing the rotating speed of the primary motor; the rotating speed of the primary motor is not adjusted until the pressure value is equal to the set target value; and in the whole process, controlling the rotating speed of the secondary motor according to a preset rotating speed ratio.

And then, the air compressor normally runs, the rotating speed of the primary motor is adjusted according to the secondary exhaust pressure (the same as that in starting), the rotating speed of the secondary motor is equal to the rotating speed of the primary motor and the rotating speed ratio, and the rotating speed ratio is adjusted by adopting a PID control method.

The above description is only an embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any insubstantial modifications made by using the design concept should fall within the scope of infringing the present invention.