Ship Power Plants 
DOI: http://www.dx.doi.org/10.24866/2227-6858/2020-2-7

Khannanov A., Chupina K., Usoltcev V.

ANDREY KHANNANOV, Candidate of Engineering Sciences, Associate Professor, e-mail: hanr@mail.ru
KIRA CHUPINA, Candidate of Engineering Sciences, Associate Professor, e-mail: chupina.kv@dvfu.ru
VALERY USOLTCEV, Candidate of Engineering Sciences, Associate Professor, e-mail: usvalerij@yandex.ru
Department of Ship Energy and Automation, School of Engineering
Far Eastern Federal University
Vladivostok, Russia

Increasing the astatism of the automatic control system
by introducing positive feedback

Abstract: Question status: Subordinate automatic control systems (SACS) are widely used in engineering inclusive of ship power plants. The need to limit specific parameters of the object makes them non-linear.
The use of proportional-integral regulators leads to the problem of integral saturation, the emergence of free movements in SACS when the regulators descend from the limit. The authors propose to increase astatism of SACS and solve the problem of integral saturation by introducing additional positive feedback.
Materials and methods: Analysis of mathematical models of non-linear SACS and their digital modeling are used.
Results: A mathematical model of one of the ACS loops with additional positive feedback is described. It is confirmed that introduction of positive feedback can increase astatism of SACS and eliminate the effect of integral saturation with first-order astatism, which increases the accuracy of SACS when processing control signals. A new method is proposed to eliminate the effect of integral saturation in wide-range voltage regulators of onboard synchronous generators of field lighting systems without the use of hardware protective equipment.
Conclusions: the efficiency of introducing additional positive feedback to increase the accuracy of SACS and eliminate the effect of integral saturation is duly evidenced. Low sensitivity of the effect of positive feedback introduction to the change of SACS parameters is as well noted.
Keywords: automatic control system, subordinate regulation, saturation of the regulator, positive feedback, mathematical model, digital modeling, astatism.

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