Chepkunov R. Improving of the quality of control of the electric drives with indirect speed measuring

The thesis is devoted to the research of the limits associated with stability of the control system of electric drives with indirect speed measuring and to basing of the increase of quality of control of direct current drive and asynchronous electric drive by strengthening of the positive current feedback for full compensation of statyzma of mechanical characteristics of the motor with the assumption of overcompensation in case of temperature changing of parameters. It is defined the stability factors of the control system at overcompensation of statyzma of mechanical characteristics of the motor. It is defined limitations wich are associated with the stability of regulation contour with thyristor converter at digital smoothing of pulses by the way of multiple measuring and averaging of the feedback signal in the period of discreteness with definition of middle value, which allows to reduce the voltage and current sensors inertia. It is developed a new scheme for speed control, which ensures increasing of quality of regulation by the introduction the positive current feedback to the input of the limitation of the current regulator set circuit. It is shown that indirect speed measuring in asynchronous electric drive impairs stability of induction motor. The parameters of induction motor, at which self-oscillations are possible, are determinated. It is developed the scheme of their suppression with the help of feedback of the reactive component of current, which does not degrade the quality of speed regulation. The results of research are applied in medium and high power direct current drives and alternating current drives at Zaporozhye elektroapparatus plant and the Ukrainian Institute of Power Electronics "Preobrazovatel".