Double-frequency-conversion common-direct-current brake control system of horizontal screw centrifuge

Abstract

The utility model relates to the field of centrifugal machines, and discloses a double-frequency-conversion common-direct-current brake control system of a horizontal screw centrifugal machine, which mainly comprises a main frequency converter, an auxiliary frequency converter, a brake unit (energy consumption brake or regenerative brake), a contactor, a diode, a fuse and the like. Under the condition that an original double-frequency-conversion common-direct-current-bus control system is not changed, through the mode of the utility model, the quick stopping and braking function of the horizontal spiral centrifugal machine can be realized, and the problems of long stopping time and high stopping speed of the horizontal spiral centrifugal machine controlled by the double-frequency-conversion common-direct-current-bus in the prior art are solved. And emergency braking and stopping of equipment due to abnormal vibration and other conditions cannot be effectively met.

Description

Technical Field

[0001] The utility model relates to the field of centrifuges, in particular to a double-frequency common DC braking control system for a horizontal spiral centrifuge. Background Art

[0002] In the double-frequency control system of a horizontal spiral centrifuge, the main frequency converter and the auxiliary frequency converter often adopt a common DC bus control method. The purpose is that during the separation of materials by the centrifuge, the spiral driven by the auxiliary motor lags behind the drum driven by the main motor. Through the friction of the materials, the spiral brakes the drum, and the drum pushes the spiral. Therefore, the drum drive motor (main motor) is in the electric state, while the spiral drive motor (auxiliary motor) is in the power generation state. With this structure, the energy generated by the spiral drive motor can be sent back to the main frequency conversion inverter circuit through the common DC bus via the auxiliary frequency conversion inverter circuit, acting as part of the electric energy of the drum drive motor, realizing the recycling of electric energy.

[0003] However, a horizontal spiral centrifuge is a high-speed rotating device. To meet the needs of industrial development and so on, horizontal spiral centrifuges are also developing in the direction of large specifications, large processing capacities, and high separation factors. In this way, the rotating part of the equipment will be larger and heavier, and the moment of inertia of the equipment will also be larger. Although the double-frequency common DC bus control can recycle the electric energy generated by the auxiliary motor drive during the normal operation of the equipment for braking, the braking ability of this system is almost the same as free parking during the emergency stop of the equipment, with a long parking time. The parking time cannot effectively meet the need for emergency braking and parking of the equipment due to abnormal vibration and other situations, and there are still deficiencies in the safety guarantee control of the equipment. Summary of the Utility Model

[0004] The utility model aims to provide a double-frequency common DC braking control system for a horizontal spiral centrifuge to solve the problem that the parking time of a horizontal spiral centrifuge controlled by the double-frequency common DC bus in the prior art is long and cannot effectively meet the need for emergency braking and parking of the equipment due to abnormal vibration and other situations.

[0005] To achieve the above object, the utility model adopts the following technical scheme: A double-frequency common DC braking control system for a horizontal spiral centrifuge, comprising:

[0006] A main motor connected to a main frequency converter, the main motor is connected to the drum of the horizontal spiral centrifuge for driving the drum to rotate;

[0007] An auxiliary motor connected to an auxiliary frequency converter, the auxiliary motor is connected to the spiral of the horizontal spiral centrifuge for driving the spiral to rotate; the power of the auxiliary frequency converter is less than that of the main frequency converter;

[0008] A braking unit, which brakes the horizontal spiral centrifuge for parking under the drive of electric energy;

[0009] A DC bus circuit is connected between the main frequency converter and the auxiliary frequency converter. A braking unit is connected in series on the DC bus circuit. A fuse is connected between the braking unit and the DC bus circuit. A contactor and a diode are also connected to the DC bus circuit, and the diode conducts unidirectionally to the main frequency converter.

[0010] Preferably, as an improvement, the contactor is linked with the starting electrical signal of the horizontal screw centrifuge.

[0011] Preferably, as an improvement, the braking unit is an energy consumption braking unit or a feedback braking unit.

[0012] The principle and advantages of this solution are as follows: In practical applications, in the double-frequency control system of the horizontal screw centrifuge, the main frequency converter and the auxiliary frequency converter often adopt the control method of sharing a common DC bus. The purpose is that during the separation process of the centrifuge for materials, the spiral driven by the auxiliary motor lags behind the drum driven by the main motor. Through the friction of the materials, the spiral plays a braking role on the drum, while the drum plays a pushing role on the spiral. Therefore, the main motor is in the electric state, while the auxiliary motor is in the generating state. The energy generated by the auxiliary motor can be sent back to the inverter circuit of the main frequency converter through the shared DC bus via the inverter circuit of the auxiliary frequency converter, acting as a part of the electrical energy of the main motor, realizing the recycling of electrical energy. In this solution, a diode that conducts unidirectionally to the main frequency converter is set on the DC bus circuit to prevent the voltage of the main frequency converter from flowing back and impacting the auxiliary frequency converter under abnormal conditions. A contactor is set on the DC bus to be linked with the starting signal of the horizontal screw centrifuge to be attracted, ensuring the synchronous operation of this system during the normal operation of the horizontal screw centrifuge. The fuse serves as a guarantee mechanism for the braking unit to avoid damage to the braking unit due to excessive current in the braking circuit. During the deceleration and shutdown process of the horizontal screw centrifuge, both the main frequency converter and the auxiliary frequency converter are in the braking state. At this time, the DC voltage of the DC bus circuit will increase, triggering the braking unit to work and quickly consuming the braking electrical energy during the shutdown process, realizing the rapid braking and stopping of the horizontal screw centrifuge, and thus meeting the requirement of emergency braking and stopping due to abnormal vibrations and other situations. In this way, the technical solution of the present utility model is compatible with the original double-frequency common DC bus control function without changing the original double-frequency common DC bus control system, and designs and optimizes to add a rapid braking and stopping function, improving the safety guarantee of equipment operation. Description of the Drawings

[0013] Figure 1 It is a structural schematic diagram of an embodiment of the present utility model.

[0014] Figure 2 It is a circuit schematic diagram of an embodiment of the present utility model. Detailed Embodiment

[0015] The following is further detailed through specific embodiments:

[0016] The reference numerals in the accompanying drawings of the specification include: horizontal screw centrifuge 1, main motor 2, main frequency converter 3, auxiliary motor 4, auxiliary frequency converter 5, braking unit 6, power supply 7, DC bus circuit 8, contactor 9, diode 10, fuse 11.

[0017] The embodiment is basically as shown in the attached Figure 1 , Figure 2 figures: A double-frequency common DC braking control system for a horizontal screw centrifuge, including a main motor 2 connected to a main frequency converter 3, and the main motor 2 is connected to the drum of the horizontal screw centrifuge 1 for driving the drum to rotate; an auxiliary motor 4 connected to an auxiliary frequency converter 5, and the auxiliary motor 4 is connected to the screw of the horizontal screw centrifuge 1 for driving the screw to rotate. The power of the auxiliary frequency converter 5 is less than that of the main frequency converter 3, and the main frequency converter 3 and the auxiliary frequency converter 5 are connected in parallel in the power supply 7 circuit. A braking unit 6, which brakes the horizontal screw centrifuge 1 to stop under the drive of electric energy. In this embodiment, the braking unit 6 is preferably an energy consumption braking unit 6. A DC bus circuit 8 is connected between the main frequency converter 3 and the auxiliary frequency converter 5, the braking unit 6 is connected in series on the DC bus circuit 8, a fuse 11 is connected between the braking unit 6 and the DC bus circuit 8, a contactor 9 and a diode 10 are also connected on the DC bus circuit 8, and the contactor 9 is linked to the start signal of the horizontal screw centrifuge 1 to close, and the diode 10 conducts unidirectionally to the main frequency converter 3.

[0018] The specific implementation process is as follows: The diode 10 is a protection circuit. Since the power of the auxiliary frequency converter 5 of the horizontal screw centrifuge 1 is less than that of the main frequency converter 3, in order to prevent the DC bus voltage of the main frequency converter 3 from flowing back and impacting the auxiliary frequency converter 5 under abnormal conditions, the diode 10 is added to ensure the unidirectional conduction of the DC bus circuit 8. At the same time, in order to ensure the controllability of the common DC bus of the control system, a contactor 9 is added to the DC bus circuit 8, and the contactor 9 will only be linked to close during the normal operation of the horizontal screw centrifuge 1. The fuse 11 is a guarantee device for the braking unit 6 circuit to avoid damage to the braking unit 6 due to excessive braking circuit current.

[0019] During the normal operation of the horizontal screw centrifuge 1 in this control system, the contactor 9 will be linked to the equipment start signal to close. At the same time, the electric energy generated by the rotation of the drum at the auxiliary motor 4 is fed back to the main frequency converter 3 inverter circuit through the DC bus via the inverter circuit of the auxiliary frequency converter 5 for electric energy recycling. During the deceleration and shutdown process of the horizontal screw centrifuge 1, both the main frequency converter 3 and the auxiliary frequency converter 5 are in the braking state. At this time, the DC voltage of the DC bus circuit 8 will rise and trigger the braking unit 6 to work, quickly consuming the braking electric energy during the equipment shutdown process (through the braking resistor or energy feedback method), realizing the fast braking and stopping function of the horizontal screw centrifuge 1. This is compatible with the original double-frequency common DC bus control function, and the design is optimized to add a fast braking and stopping function, improving the safety guarantee of equipment operation.

[0020] The above are only embodiments of the present utility model, and common general technical solutions and / or characteristics in the solutions are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solutions of the present utility model, several modifications and improvements can be made, which should also be regarded as the protection scope of the present utility model, and these will not affect the implementation effect of the present utility model and the practicability of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners and the like recorded in the specification can be used to interpret the content of the claims.

Claims

1. A double-frequency common DC braking control system for a horizontal scroll centrifuge, characterized in that: including a main motor connected to a main frequency converter, the main motor being connected to a scroll centrifuge drum for driving the drum to rotate; a secondary motor connected to a secondary frequency converter, the secondary motor being connected to a scroll of the scroll centrifuge for driving the scroll to rotate; the power of the secondary frequency converter is less than that of the main frequency converter; a braking unit that brakes the scroll centrifuge to stop under electric drive; a DC bus circuit is connected between the main frequency converter and the secondary frequency converter, the braking unit is connected in series on the DC bus circuit, a fuse is connected between the braking unit and the DC bus circuit, a contactor and a diode are also connected to the DC bus circuit, and the diode conducts unidirectionally to the main frequency converter.

2. The double-frequency common DC braking control system of a scroll centrifuge according to claim 1, characterized in that: The contactor is linked with the start electric signal of the scroll centrifuge.

3. The double-frequency common DC braking control system of a scroll centrifuge according to claim 2, characterized in that: The braking unit is an energy consumption braking unit or a regenerative braking unit.

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