| Excitation system is an important part of synchronous motor running system ,it affects the operating characteristics of motor directly. Especially in the excitation system of synchronous motor powered by converter ,it needs more reliability, security and communication functions. This paper introduces a kind of design and research of the excitation control system of synchronous motor powered by converter.In order to satisfy the requirement of naval vessels drive to reliability and security of regulator, the design adopts two-channel architecture strategy i.e. it consists of two identical completely and independent channels. Each channel of microcomputer excitation regulator is spare for the other, it is consisted of separate control unit, power unit and signals unit. The key to exerting merit of dual channels excitation regulation is that they track one another and exchange information so as to switch smoothly when one failure takes place. In the same time, the control unit adopts PLC, because of its reliability and communicating ability. In order to protect losing steps, the way that prejudging power angel protects losing steps was brought forward and simulated by MATLAB.According to the scheme, the paper discusses the hardware and software of the regulator, introduces the design of center control unit adopted S7-200 and signal conversion circuit (4~20mA) excitation current given circuit, current conversion circuit and voltage conversion circuit; in this paper it describes the software of regulator, introduces programmed logic, subroutine and module design methods of asynchronous timing interrupt in details and makes experiment, for example, improved PID and parameters adjustment, communication between channels, communication with upper computer and converter, A/D and D/A conversion, nixie display. These experiments succeed and achieved waveform.In order to inspect the currents, voltages, errors in two channels in real time, the design adopt "kingview" soft. Through the soft, we can know the operating states of the excitationsystem, in the same time the soft can also record all kinds of data. It can adjust the parameters of PID and provide research and study with data.The experiment proves that the regulator has good performance,simple hardware, high reliability and strong ability to resist disturbment,it has high practical and using value. |
