Permanent Magnet Synchronous Machine Sizing: Effect on the Energy Efficiency of an Electro-Hydraulic Forklift

Abstract

The energy efficiency of an electro-hydraulic forklift is significantly improved by using a permanent-magnetsynchronous-motor-servo-drive-based direct pump control to control the position of the fork without control valves. This paper provides a short evaluation of the hydraulic system and a more detailed analysis of the losses of the electric machine drive system. A theoretical approach is taken and the results are verified by practical measurements. Finally, possible improvements of the energy efficiency in the suggested system are discussed.

Energy-Saving Adaptive Robust Control of a Hydraulic Manipulator Using Five Cartridge Valves With an Accumulator

“…Defining the load force as p L = p 1 A 1 − p 2 A 2 , it is seen from (2) and (6) that, to achieve accurate motion tracking, the desired value of the load force (denoted as p Ld ) should be chosen at first such that q accurately tracks q d (t). Then, the desired flow rates into the two chambers Q 1m and Q 2m are chosen such that the actual load force tracks the desired one accurately.…”

“…The widespread applications of hydraulic actuators have drawn the attention of the engineers to apply the state-of-art system design, control, and fault detection techniques [2]- [10]. The control of electrohydraulic actuator systems is very challenging not only because of the high-order and highly nonlinear nature of the plant but also because the hydraulic energy consumption is a big issue that needs to be taken into account for the controller design.…”

Effect of an Electric Motor on the Energy Efficiency of an Electro-Hydraulic Forklift

“…The electric power loss analysis is based on the testing and redesign of the PMSM and the IM (Pyrhönen, 2008). A detailed description and calculations using the machine parameters measured in a fixed temperature for the PMSM are given in (Minav, 2011a). The PMSM data including the manufacturer's data, measured and calculated motor parameters are shown in Figure 6 shows the calculated efficiency of the PMSM CFM112M with some measured efficiency points.…”

“…The PMSM data including the manufacturer's data, measured and calculated motor parameters are shown in Figure 6 shows the calculated efficiency of the PMSM CFM112M with some measured efficiency points. A procedure similar to (Minav, 2011a) to produce theoretical system efficiency was performed for the induction machine test setup. This induction machine is the original safe voltage induction motor with which the lifting function of the original battery operated forklift was equipped.The electric power loss analysis for the IM is based on testing and redesign of the machine based on (Pyrhönen, 2008).…”

Improving Hydraulic System Energy Efficiency With High-Performance Hydraulic Fluids

“…Others state that, in general, in manufacturing equipment, daily operations and machine maintenance play even more important roles in improving energy efficiency [5], [6]. Permanent magnet synchronous motors have been proposed to be used in mediumsized injection molding [7] and in an electrohydraulic forklift [8] as a means of improving efficiency. Another alternative for improving hydraulic system energy efficiency is by using highperformance hydraulic fluids.…”