Енергозберігаюче керування електроприводом насоса гідравлічного крана

Abstract

На основі аналізу можливих режимів роботи палубного крана, а також на підставі розрахунків необхідної потужності насоса був обґрунтований, розроблений і запропонований алгоритм допустимого зниження оборотів двигуна головного насоса, що забезпечує суттєве зниження споживаної потужності без втрат в продуктивності при роботі неповного числа механізмів і під час технологічних пауз.

The use of hydraulic drives in deck cranes is quite common practice, since the hydraulic crane in capital costs is significantly cheaper compared to a similar functional and load-carrying electric crane. However the control of the hydraulic crane is devoid of energy saving advantages, primarily because of the archaic approach to managing the engine of the main pump, in fact, in the absence of control as such. Even modern cranes have only a contactor start circuit with the switch "star - delta". Further, the speed of the electric drive is not regulated. The speed of the mechanisms is regulated by hydraulic means using the scheme "regulated volume pump –constant volume hydraulic motor". This means that regardless of the loading of the working mechanisms hydraulic drives the main pump operates at a speed close to the nominal, creating in the system an excess pressure that is continuously dumped through the bypass valves even at the work of all mechanisms with a load lower than the nominal, since the operating point of the system "Hydraulic pump - Hydromotor" is calculated on condition of nominal loading and simultaneous operation of all mechanisms. In all other cases, the pressure in the system is redundant. Based on the analysis of possible operating modes of the deck crane, as well as on the basis of calculations of the required power of the pump, the algorithm of the allowable reduction of engine speed of the main pump was substantiated, developed and proposed, which provides a significant reduction in the power consumption without loss in productivity at work of an incomplete number of mechanisms and during technological pause The results of the proposed upgrade were supported by simulation of the processes in an upgraded scheme using the Matlab Simulink software environment. The simulation results fully confirmed the feasibility and effectiveness of the proposedreplacement of the basic framework for a modernized using VFD to reduce energy consumption according to the number of working mechanisms as well as during the technological pauses. It should be noted that the proposed use of VFD provides for setting operating speed of the main pump assuming nominal load each of the mechanisms. More precise control of the main pump can be realized by the task in the pressure system required to work with the specific value of the load moment of each of the mechanisms. But such a decision will involve some interference with the hydraulic system of the crane to install the necessary operating pressure sensors in the circuits of individual hydraulic drives.

На основе анализа возможных режимов работы палубного крана, а также на основании расчетов необходимой мощности насоса был обоснован, разработан и предложен алгоритм допустимого снижения оборотов двигателя главного насоса, обеспечивающего существенное снижение потребляемой мощности без потерь в производительности при работе неполного числа механизмов и во время технологических пауз.