The Challenge
As a core piece of equipment in the industrial sector for achieving "solid-liquid separation, liquid-liquid separation, and solid-solid classification" (e.g., chemical crystallization separation, food starch dehydration, sewage treatment sludge dehydration, and mineral separation in mines), centrifuges operating in the traditional fixed-frequency mode rely on "contactor start-stop + pulley speed regulation". This traditional mode suffers from pain points such as energy waste, low speed regulation accuracy, and large start-stop shocks. By leveraging the vector control technology of inverters, this solution adapts to the load requirements of centrifuges under different operating conditions (start-up, acceleration, stable separation, and deceleration discharge), enabling full-process intelligent control.
The Solution
With the goals of "adapting to load characteristics, ensuring separation efficiency, and reducing comprehensive costs", the design is carried out from four aspects: working condition analysis, hardware selection, system architecture, and control logic. The full operation cycle of a centrifuge is divided into 4 core stages, and the load and speed regulation requirements vary significantly in each stage, so it is necessary to design targeted inverter control strategies.
Start-up stage: Static resistance is high, and the demand for starting torque is high (requiring 1.2-1.5 times the rated torque).
Acceleration stage: The load gradually stabilizes as the speed increases, and it is necessary to quickly reach the target separation speed.
Stable separation stage: It is a constant torque load, and precise maintenance of speed stability is required (deviation ≤ ±1%).
Deceleration and discharge stage: The inertial load is large, and rapid yet smooth deceleration is necessary to avoid material residue.