Abstract:Aiming at the problems of the typical pump-controlled motor system in hydrostatic driven construction and agricultural equipment, such as the continuous power losses of the low-pressure circuit and that the loop temperature is subjected to the varying loads and tank temperature greatly, an energy-saving thermal management method was proposed based on the cooperation control of adjustable charging and flushing circuit (ACFC). Firstly, electric proportional constant-pressure variable pump and electric proportional throttle valve were introduced into the low-pressure circuit of the pump-controlled motor system to realize the adjustment of the flushing flow and the automatic adaptation of the charging flow, which provided the freedom for the loop temperature control. Secondly, based on the experimental data, the heat generation model of the pump-controlled motor system was established through the power loss method. Thirdly, a thermal management method based on feedforward+ PD feedback control algorithm and system heat generation model was introduced to control the loop temperature. Finally, the pump-controlled motor speed control strategy based on power following was introduced to carry out experimental comparison tests at different loads and different initial temperatures between typical pump-controlled motor system and the pump-controlled motor system based on ACFC. The results indicated that the established heat generation can realize the real-time estimation of the heat generation power of the pump-controlled motor system, and the estimation accuracy was within ±10%, which verified the correctness of the established system heat balance model. Furthermore, under the premise that the ACFC had certain margin of heat dissipation, the thermal management method can effectively reduce the power consumption of the low-pressure circuit by 24.7%~66.7%, while making the loop temperature control accuracy up to±0.5℃, and increasing the total efficiency by 0.9%~3.9%, which verified performance of the proposed method in terms of loop temperature control and energy saving. The thermal management method based on ACFC can provide an idea and method for the energy saving control and thermal management of the hydrostatic driven construction and agricultural equipment.
