Research and Design of an Intelligent Liquid-State Softstarter

An intelligent liquid-state soft starter is made by connecting in series a special resistance to motor stator circuit. Using embedded control technology and an intelligent control algorithm, the speed, the rise and fall of the movable polar plate can be changed, and the resistance can be changed accordingly. With liquid-state resistance reducing gradually from maximum to zero, motor can be accelerated evenly and started smoothly until its speed reaches rated speed, soft start can be realized. All experiments indicated that the liquid-state softstarter can help the high-voltage motor start smoothly. The liquid-state softstarter has many characteristics such as low starting current, start smoothly, little impact on grid and high cost performance.