The Control Method Of Softstarter And Its Application

Currently there are many traditional starting modes in the field of motortechnology, such as direct full pressure starting, Y/△, using the autotransformers.But there still exist a lot of defects. Some of the starting modes have too largevoltage drop because of too big starting current, which impacts other equipments inthe same network and asks for a large capacity of the top transformers. Some of themhave too many starting equipments, leading to a complex wiring network in thestarting circuit, or have too small starting torque.Therefore, a new soft starter was developed, which can effectively alleviate theabove defects by using the phase angle control technique in which power electroniccomponents such as SCR were controlled. Modern soft starters mostly usemicroprocessors as the core controlling components, with a wide variety of hardwarecircuits and all kinds of testing methods and algorithms. The microprocessorsprecisely control these power electronic components and then make the soft starterswith a high controlling accuracy and many displaying modes. Some high-end softstarters even have communication and remote control functions, which make the softstarters can be more easily used in all kinds of system, as well as improve theirutilization and expand the range of their applications.The proposed soft starter in this paper is an intelligent device, which uses amicro-controller as the controlling master and thyristors as the master components tobe controlled. Angle control technology is used and start-up parameters can be set inthe soft starter. Firstly, the control technology of the core components is studied andthree phase and two phase controlling methods to three-phase motors are described.Secondly, the experiment data show that the proposed soft starter is superior to sometraditional starting methods and can effectively solve their defects at the applicationlevel. Finally, the technology direction can be guided and leaded by all kinds of softstarters used in different loads, which makes the soft starter can be more widely andcorrectly applied in all industries.