抄録
This paper describes an application of an improved optimal regulator technique developed on the basis of original optimal regulator theory to synthesis of speed control system of static Scherbius induction motor system. Theoretical results are compared with the experimental results. As the processing time required to execute the employed control algorithm in a microprocessor employed as a controller of the control system is not short enough compared with the fast transient motion of the induction motor, input delay time due to the processing time is taken into account when designing the control system. In order to improve the steady state characteristics of the designed control system, integral action is introduced in the designed control system, which results in zero steady state error, unlike the original optimal regulator system. The sampling period is chosen to be 20ms which is very short compared with the mechanical time constant and is one-fifth of the electrical time constant of the controlled object. Experiments are carried out using 8-bits microprocessor connected a high speed arithmetic element in order to make floating calculations in the microprocessor system very fast and to avoid overflows in the calculations in the microprocessor system. Feedback gains obtained theoretically by means of optimal regulator technique are used in the simulation study and in the experimental study as well. The steady state error of the control system of the experimental setup is recognized to zero in spite of step change with reasonable magnitude in the desired signal and the generator type load. The transient response, however, is not improved because the control input variable corresponding to controlling angle of the cycloconverter is restricted to with in some values in order to avoid the commutation failure of the cycloconverter used in the induction motor system. That is, the magnitude of the control input variable at the transient state cannot be allowed to grow up very large value to make the system response fast. This is inevitable situation in the present controlled object. The experimental results are compared with the simulation results, and fairy close agreement is obtained which confirms the effectiveness of the improved optimal regulator technique and the exactness of the experiments.
