阅读说明：本技术 双变频差速控制方法和控制电路 (Double-frequency-conversion differential control method and control circuit ) 是由 孙芳 史锡才 *** 于 2019-12-05 设计创作，主要内容包括：本发明公开了一种双变频差速控制方法,其特征在于它将主电机和辅电机分别通过对应的主电机变频器G1和辅电机变频器G2后接入电源；基于主电机变频器G1和辅电机变频器G2的频率设置,实现主电机和辅电机的电机差速。双变频控制差速的方法采用主变频器和辅变频器来调节让主电机和辅电机保持一定的差速来实现差速器的功能,变频器调速精度高,只要通过变频器改变差速电机的转速就可以调节差速,差速直接驱动系统可在整个差速范围内实现瞬间全自动精确控制。(The invention discloses a double-frequency-conversion differential control method which is characterized in that a main motor and an auxiliary motor are respectively connected into a power supply after passing through a corresponding main motor frequency converter G1 and an auxiliary motor frequency converter G2; based on the frequency setting of the main motor frequency converter G1 and the auxiliary motor frequency converter G2, the motor differential speed of the main motor and the auxiliary motor is realized. The method for controlling the differential speed by double frequency conversion adopts a main frequency converter and an auxiliary frequency converter to adjust and enable the main motor and the auxiliary motor to keep a certain differential speed to realize the function of a differential mechanism, the speed regulation precision of the frequency converter is high, the differential speed can be adjusted only by changing the rotating speed of the differential motor through the frequency converter, and the differential direct drive system can realize instant full-automatic accurate control in the whole differential speed range.)

1. A double-frequency-conversion differential control method is characterized in that a main motor and an auxiliary motor are respectively connected to a power supply through a corresponding main motor frequency converter G1 and an auxiliary motor frequency converter G2; based on the frequency setting of the main motor frequency converter G1 and the auxiliary motor frequency converter G2, the motor differential speed of the main motor and the auxiliary motor is realized.

2. The dual-inverter differential control method as claimed in claim 1, wherein the rectified DC power source of the main motor inverter G1 is connected to the DC bus box of the auxiliary motor inverter G2, the mechanical energy transmitted by the main motor is converted into electric energy, and the regenerated energy is fed back to the DC bus of the auxiliary motor inverter through the auxiliary motor inverter.

3. The dual variable frequency differential control method according to claim 1, wherein the frequency of the inverter determines the motor speed, and is obtained by the following formula:

n＝60f(1-s)/p

where f is the motor frequency, n is the rotational speed, s is the slip, and p is the pole pair number.

4. The dual variable frequency differential control method according to claim 1, wherein the differential speed of the centrifuge is monitored and compared with a set differential speed; the auxiliary motor frequency converter G2 adjusts the frequency of the auxiliary motor, so that the differential error of the centrifuge is adjusted in the direction of reducing.

5. The dual-frequency-conversion differential control method according to claim 4, characterized in that:

when the differential speed of the centrifuge is reduced compared with a set value, the frequency of an auxiliary machine frequency converter is automatically adjusted downwards, so that the differential speed is increased;

when the differential speed of the centrifugal machine is increased compared with the set value, the frequency of the auxiliary frequency converter is automatically adjusted upwards, so that the differential speed is reduced.

6. A double variable frequency differential control circuit for implementing a double variable frequency differential control method according to any one of claims 1 to 3, characterized in that it comprises a main loop and a control loop:

a main loop: the power supply correspondingly accesses the main motor and the auxiliary motor after passing through a main motor frequency converter G1 and an auxiliary motor frequency converter G2 respectively, and a circuit breaker Q1 is arranged between the power supply and the frequency converters;

a control loop comprising:

a main power supply connection loop: the power supply is connected with a FAN power supply FAN of the frequency converter cabinet after passing through an auxiliary contact of a breaker Q1;

start/stop loop: the power supply is sequentially connected with a main motor frequency converter G1 switch, an auxiliary motor frequency converter G2 switch, a stop switch S12, a start switch S11 and an electromagnetic coil of an electromagnetic relay KA1 which are connected in series; a normally open contact of the electromagnetic relay KA1 is connected with the normally open switch S11 in parallel;

main motor operation/set rotation speed: the normally open contact of the KA1 of the electromagnetic relay controls the on-off of the main motor frequency converter G1, and the DCS is used for setting the rotating speed of the main motor frequency converter G1;

auxiliary motor operation/set rotation speed: the switch of the main motor frequency converter G1 controls the on-off of the auxiliary motor frequency converter G2, and the rotating speed is set for the auxiliary motor frequency converter G2 through DCS.

7. The dual-frequency-conversion differential control circuit as claimed in claim 6, wherein the rectified DC power supply of the main motor frequency converter G1 is connected with the DC bus box of the auxiliary motor frequency converter G2; parallelly connected time relay KT 1's solenoid on converter cabinet FAN power FAN, control circuit still includes the feedback brake circuit: the power supply is connected with the electromagnetic coil of the electromagnetic relay KM1 through the normally open contact of the time relay KT 1; the normally open contact of the electromagnetic relay KM1 was set on the connection line of the main motor frequency converter G1 and the auxiliary motor frequency converter G2.

Technical Field

The invention relates to the field of differential control of centrifugal dehydrator equipment, in particular to a double-frequency-conversion differential control method and a control circuit.

Background

The differential device that uses in the centrifugal dehydrator equipment in the engineering is mostly hydraulic pressure differential mechanism, and hydraulic pressure differential mechanism is that a second grade planetary gear reducer constitutes, and this mechanism passes through the fix with screw on the centrifuge drum, provides suitable differential rotation speed for centrifuge's spiral and drum in centrifuge working process. Hydraulic differentials are one type of variable displacement radial piston motor. The pressure exerted on the piston ball by the oil inlet of the pump station is transmitted through the cam disc. While the tangential separation causes the rotor to rotate. Pressure is applied to the piston by the dispenser causing the piston to move. And then the hydraulic oil is conveyed back to the hydraulic pump station through a loop, and the oil cylinder alternately acts the high pressure of the oil inlet system on the differential mechanism, so that the differential mechanism piston is driven to move, and the differential mechanism is further operated. The high pressure of the oil inlet is decompressed after acting, and then is conveyed back to the pump station, so that the spiral and the rotary drum generate a constant differential rotation speed, the dehydrated solid-phase sediment is pushed out from a small-end sediment outlet of the conical rotary drum, and the liquid with light specific gravity flows out from an overflow port at the cylindrical end. The lubrication of the hydraulic differential is a lubrication mode combining dipping bath and splashing, and during operation, the oil temperature is high, the oil is easy to leak under the action of centrifugal force, the oil storage amount needs to be checked frequently, and the oil is supplemented timely.

Fig. 1 is a conventional differential. The hydraulic differential mechanism has the defects of high failure rate of the planetary gear and the planetary gear sliding bearing in the using process, easy tooth breakage due to increased tooth surface abrasion, difficult processing, short service life, high noise, difficult maintenance and the like.

Disclosure of Invention

The invention provides a novel differential control method, which mainly solves the defects of a differential in use and solves the problems existing in the operation of a centrifugal dehydrator.

The technical scheme is as follows:

the invention discloses a double-frequency-conversion differential control method, which comprises the steps that a main motor and an auxiliary motor are respectively connected into a power supply through a corresponding main motor frequency converter G1 and an auxiliary motor frequency converter G2; based on the frequency setting of the main motor frequency converter G1 and the auxiliary motor frequency converter G2, the motor differential speed of the main motor and the auxiliary motor is realized.

Preferably, the rectified dc power source of the main motor inverter G1 is connected to the dc bus box of the auxiliary motor inverter G2, and the mechanical energy transmitted by the main motor is converted into electrical energy, and the regenerated energy is fed back to the dc bus of the auxiliary motor inverter through the auxiliary motor inverter.

Preferably, the frequency of the frequency converter determines the motor speed, and is obtained by the following formula:

n＝60f(1-s)/p

where f is the motor frequency, n is the rotational speed, s is the slip, and p is the pole pair number.

Preferably, the differential speed of the centrifuge is monitored and compared with the set differential speed; the auxiliary motor frequency converter G2 adjusts the frequency of the auxiliary motor, so that the differential error of the centrifuge is adjusted in the direction of reducing.

Specifically, the method comprises the following steps:

when the differential speed of the centrifuge is reduced compared with a set value, the frequency of an auxiliary machine frequency converter is automatically adjusted downwards, so that the differential speed is increased;

when the differential speed of the centrifugal machine is increased compared with the set value, the frequency of the auxiliary frequency converter is automatically adjusted upwards, so that the differential speed is reduced.

The invention also discloses a double-frequency-conversion differential control circuit, which is used for realizing the double-frequency-conversion differential control method, and comprises a main loop and a control loop:

a main loop: the power supply correspondingly accesses the main motor and the auxiliary motor after passing through a main motor frequency converter G1 and an auxiliary motor frequency converter G2 respectively, and a circuit breaker Q1 is arranged between the power supply and the frequency converters;

a control loop comprising:

a main power supply connection loop: the power supply is connected with a FAN power supply FAN of the frequency converter cabinet after passing through an auxiliary contact of a breaker Q1;

start/stop loop: the power supply is sequentially connected with a main motor frequency converter G1 switch, an auxiliary motor frequency converter G2 switch, a stop switch S12, a start switch S11 and an electromagnetic coil of an electromagnetic relay KA1 which are connected in series; a normally open contact of the electromagnetic relay KA1 is connected with the normally open switch S11 in parallel;

main motor operation/set rotation speed: the normally open contact of the KA1 of the electromagnetic relay controls the on-off of the main motor frequency converter G1, and the DCS is used for setting the rotating speed of the main motor frequency converter G1;

auxiliary motor operation/set rotation speed: the switch of the main motor frequency converter G1 controls the on-off of the auxiliary motor frequency converter G2, and the rotating speed is set for the auxiliary motor frequency converter G2 through DCS.

Preferably, the direct current power supply rectified by the main motor frequency converter G1 is connected with a direct current bus box of the auxiliary motor frequency converter G2; parallelly connected time relay KT 1's solenoid on converter cabinet FAN power FAN, control circuit still includes the feedback brake circuit: the power supply is connected with the electromagnetic coil of the electromagnetic relay KM1 through the normally open contact of the time relay KT 1; the normally open contact of the electromagnetic relay KM1 was set on the connection line of the main motor frequency converter G1 and the auxiliary motor frequency converter G2.

The invention has the advantages of

The method for controlling the differential speed by double frequency conversion adopts a main frequency converter and an auxiliary frequency converter to adjust and enable the main motor and the auxiliary motor to keep a certain differential speed to realize the function of a differential mechanism, the speed regulation precision of the frequency converter is high, the differential speed can be adjusted only by changing the rotating speed of the differential motor through the frequency converter, and the differential direct drive system can realize instant full-automatic accurate control in the whole differential speed range. The double-frequency-conversion control differential system can save electric energy at the same time, the auxiliary motor converts mechanical energy transmitted by the main motor into electric energy, and regenerated energy is fed back to a direct-current bus of the auxiliary-motor frequency converter to complete energy recovery.

Drawings

FIG. 1 is a hydraulic differential in the background art

FIG. 2 shows a dual frequency differential control circuit

Detailed Description

The invention is further illustrated by the following examples, without limiting the scope of the invention:

with reference to fig. 2, a dual-frequency-conversion differential control circuit includes a main circuit and a control circuit:

a main loop: the power supply correspondingly accesses the main motor and the auxiliary motor after passing through a main motor frequency converter G1 and an auxiliary motor frequency converter G2 respectively, and a circuit breaker Q1 is arranged between the power supply and the frequency converters;

a control loop comprising:

-a mains power-on loop: the power supply is connected with a FAN power supply FAN of the frequency converter cabinet after passing through an auxiliary contact of a breaker Q1;

-start/stop loop: the power supply is sequentially connected with a main motor frequency converter G1 switch, an auxiliary motor frequency converter G2 switch, a stop switch S12, a start switch S11 and an electromagnetic coil of an electromagnetic relay KA1 which are connected in series; a normally open contact of the electromagnetic relay KA1 is connected with the normally open switch S11 in parallel;

main machine running/set speed: the normally open contact of the KA1 of the electromagnetic relay controls the on-off of the main motor frequency converter G1, and the DCS is used for setting the rotating speed of the main motor frequency converter G1;

auxiliary motor operation/set rotation speed: the switch of the main motor frequency converter G1 controls the on-off of the auxiliary motor frequency converter G2, and the rotating speed is set for the auxiliary motor frequency converter G2 through DCS.

The control method comprises the following steps:

the control loop circuit breaker Q1 assists a contact to close and connect a FAN power supply FAN of the frequency converter cabinet and a time relay KT1, and at the moment, a FAN in the frequency converter cabinet runs; after the time relay KT1 delays, the KM1 coil gets electricity, the KM1 main contact is closed, and the main motor frequency converter G1 is communicated with the auxiliary motor frequency converter G2 through a direct-current bus to form a feedback brake loop.

When a starting button S11 is manually pressed, KA1 is electrified, a normally open contact of the starting button is closed, a main motor frequency converter G1 is connected with a starting loop, and the main motor operates; the running state of the main motor frequency converter G1 is connected to the starting loop of the auxiliary motor frequency converter G2, and the auxiliary motor runs.

The main motor and the auxiliary motor set different 4-20 mA speed signals for a main motor frequency converter G1 and an auxiliary motor frequency converter G2 through DCS according to the requirements of a process system, the rotating speed (n is 60f (1-s)/p) and the frequency are in a direct proportion relation, the main motor frequency converter and the auxiliary motor frequency converter respectively operate at corresponding frequencies after the DCS is subjected to speed regulation, different frequencies correspond to the rotating speeds of the respective corresponding motors, and when the frequencies of the two frequency converters are kept to be different, the operating speed of the motors is kept to be different.

Monitoring the differential speed of the centrifuge, and comparing the differential speed with a set differential speed; the auxiliary motor frequency converter G2 adjusts the frequency of the auxiliary motor, so that the differential error of the centrifuge is adjusted in the direction of reducing.

Preferably:

when the differential speed of the centrifuge is reduced compared with a set value, the frequency of an auxiliary machine frequency converter is automatically adjusted downwards, so that the differential speed is increased;

when the differential speed of the centrifugal machine is increased compared with the set value, the frequency of the auxiliary frequency converter is automatically adjusted upwards, so that the differential speed is reduced.

The method for controlling the differential speed by double frequency conversion adopts a main frequency converter and an auxiliary frequency converter to adjust and enable the main motor and the auxiliary motor to keep a certain differential speed to realize the function of a differential mechanism, the speed regulation precision of the frequency converter is high, the differential speed can be adjusted only by changing the rotating speed of the differential motor through the frequency converter, and the differential direct drive system can realize instant full-automatic accurate control in the whole differential speed range.

In a preferred embodiment, a direct current power supply rectified by a main motor frequency converter G1 is connected with a direct current bus box of an auxiliary motor frequency converter G2; parallelly connected time relay KT 1's solenoid on converter cabinet FAN power FAN, control circuit still includes the feedback brake circuit: the power supply is connected with the electromagnetic coil of the electromagnetic relay KM1 through the normally open contact of the time relay KT 1; the normally open contact of the electromagnetic relay KM1 was set on the connection line of the main motor frequency converter G1 and the auxiliary motor frequency converter G2.

The control loop circuit breaker Q1 assists a contact to close and connect a FAN power supply FAN of the frequency converter cabinet and a time relay KT1, and at the moment, a FAN in the frequency converter cabinet runs; after the time relay KT1 delays, the KM1 coil gets electricity, the KM1 main contact is closed, and the main motor frequency converter G1 is communicated with the auxiliary motor frequency converter G2 through a direct-current bus to form a feedback brake loop.

The double-frequency-conversion control differential system can save electric energy at the same time, the auxiliary motor converts mechanical energy transmitted by the main motor into electric energy, and regenerated energy is fed back to a direct-current bus of the auxiliary-motor frequency converter to complete energy recovery.

When the main motor or the auxiliary motor is mechanically dragged, the main motor or the auxiliary motor can be used as a generator to feed back energy to the frequency converter, and most of the stored energy is converted into electric energy by the motor and fed back to the frequency converter in the speed reduction stage of the alternating current motor and the load. When the main motor or the auxiliary motor works in an electric state, the frequency converter obtains electric energy from the bus; when the main motor or the auxiliary motor works in a power generation state, energy is directly fed back to the power grid through the bus and the feedback device, so that the aims of saving energy, improving the running reliability of equipment, reducing the maintenance amount of the equipment, reducing the floor area of the equipment and the like are fulfilled.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.