Operating Performance of Pure Electric Loaders with Different Types of Motors Based on Simulation Analysis

1. Introduction

Wheel loaders are widely used for earth-moving work in construction projects, such as roads, buildings, ports and mines, and are important machines, that are in construction in large numbers [ 1 ]. With air pollution and oil shortages becoming increasingly serious, traditional diesel-powered loaders have gradually attracted attention due to their weak emissions, high-energy consumption and low efficiency during operation. Electric-powered drive technology is an effective energy-saving and emission-reduction technology. Electric construction vehicles such as loaders using high-efficiency motors as power units can effectively reduce energy consumption [ 2 4 ]. With reference to the types of electric-powered vehicles [ 5 ], three routes are available if the loader is to be electrified according to their different power sources, i.e., hybrid-electric loaders, battery-electric loaders and fuel cell loaders. Of these, battery-electric and fuel cell loaders can be classified as purely electric-powered loaders. Most researches have focused on hybrid-electric loaders. However, hybrid systems still use the engine as the power source, leaving the problems of oil consumption and pollutant emissions unresolved. Pure electric technology has the advantages of a wide range of power sources, less pollution, low noise and high efficiency [ 6 7 ], making this source become the primary choice for energy saving and emission reduction [ 8 ].

The motor is one of the core components of all three types of electric loaders. Different types of power motors have a special performance, and different choices will directly lead to different working performances of the electric-powered loaders. Jin, Shi and Bian [ 9 ] designed and tested a power-distributed Wheel Loader with the travel and braking system using two permanent magnet synchronous hub motors and the hydraulic system driven by using an induction motor. Li, Liu, Zhao and Wang [ 10 ] designed a fuel-cell hybrid loader with two AC synchronous motors to drive the walking system and the hydraulic system respectively. Moreover, Liu, Liu and Chen [ 11 ] studied the application of switched reluctance motors (SRM) in heavy-duty vehicles, such as loaders, and showed that SRM can effectively improve the performance and reliability of heavy-duty vehicles. The above-mentioned studies showed that permanent magnet synchronous motors (PMSM), induction motors (IM) and SRM are all available options for electric loaders. However, previous researchers did not quantitatively consider the impact of the motor type on loader performances when designing the electric loader. They only summarise the advantages of the selected motor and consider that the selected motor can meet the basic work requirements of the loader. Currently, no literature investigates the most suitable motor for a loader’s operational performance.

Therefore, this study examines the operating performance of a ZL08 electric-powered loader under three types of motor drive, aiming to provide a theoretical basis for the design of electric-powered loaders. The contribution of this paper is summarised as follows. (1) The pure electrification of construction vehicles is currently in its infancy, and this paper provides a feasible solution for the selection of motor types and parameters for pure electric loaders. (2) Based on the “Matlab/Simulink-MBD-DEM” combined method, this paper proposes a set of accurate and complete loader performance simulation test plan. The vehicle performance can be known in advance before the actual vehicle manufacturing of the loader. Compared with previous studies, the model established in this paper comprehensively considers mechanical assembly, hydraulic system, multi-body dynamics, material dynamics, etc., and the degree of simulation is more higher than before. Based on this approach, key technologies such as parameter matching and control strategies can also be further investigated to reduce the time-consuming and costly development of pure electric engineering vehicles.