In this paper, the principle, structure of the Active Power Filter (APF) system and PWM control are all discussed, and based on the improved instantaneous reactive power theory, a kind of fast feasible algorithm for distortion currents detection, harmonic current suppression and reactive power compensation in shunt active power filter is put forward, meanwhile, considering the problem of power devices active power loss in the main circuit, compensating current feedback and DC bus link voltage control are added, finally, a shunt active power filter for typical current harmonic source with thyristor rectifier load is simulated based on MATLAB/Simulink toolbox, by the detailed simulation experiments, in-depth research and analysis of the simulation results, the correctness and feasibility of the compensation scheme for harmonic current detection and APF system are all verified. The proposed scheme of the harmonic current suppression and reactive power compensation is achieved, which can provide a good reference to the research and design of APF.

Highly enhanced pump power density inevitably results in a profound rise in pump temperature, which seriously influences both power loss and service performance. Heat loss analysis is an important part of analyzing the mechanical and cooling efficiency of a 2D piston pump. This paper focuses on heat loss analysis of this pump’s transmission. Firstly, theoretical and experimental studies are carried out on the thermal–hydraulic model to investigate the heat loss of the pump’s transmission. A pump test rig is developed and thermal experiments are conducted, from 1000 rpm to 6000 rpm. Furthermore, its transient thermal simulation model is implemented with Ansys software to capture the pump’s thermal status. The test convective heat transfer coefficients and temperature data are set in the model, and the simulation results are mutually validated with the experimental ones. Finally, the transmission’s heat loss is compared with its reference churning loss formula. The distribution of the transient heat loss is 49.66% into the end cap, 27.74% into the cylinder head, 13.30% into the inner cylinder, and 9.30% into the oil. The heat loss simulation results agree with the churning loss below 4000 rpm; therefore, the transmission thermal model is accurate and efficient.