Due to the proliferation and development of power electronics equipments (nonlinear loads) in utility power system, the current quality problems such as reactive power, current harmonics and neutral current in power system are deteriorated. These current quality problems may affect the safety operation and increase the loss of the electrical equipments and power system especially the Three-phase Four-wire system. In order to solve the current quality problems, power filters are widely used. Considering the cost, compensation performance, power loss and physical size, the shunt LC coupling hybrid active power filter (LC-HAPF) seems to be the best choice as current quality compensator. Due to the dc-link voltage directly affects the cost, compensation performance and the power loss of the LC-HAPF, therefore, in this thesis, the researchers are mainly focused on reducing the dc-link voltage and analyzing the dc-link voltage control. Based on the single-phase equivalent circuit of the LC-HAPF, the minimum dc-link voltage for the LC-HAPF can be deduced according to the loading currents and the parameters of the LC-HAPF passive part. However, in order to further reduce the requirement of the LC-HAPF minimum dc-link voltages, according to the average large-signal mathematical model of three-phase four-wire center-split LC-HAPF in d-q-0 coordinate, a tuned coupling neutral inductor is possible to further reduce the requirement of the dc-link voltage, so as further reducing switching loss and switching noise. Simulation results indicated that the harmonic, reactive and neutral currents in Three-phase Four-wire system can be good compensated under a low dc-link voltage LC-HAPF. For the conventional APF, when the APF works under current-mode control scheme, the dc-link voltage control is done by adding the dc voltage control signal to the compensation current as an active component. However, based on the hysteresis PWM mathematical mode and simplified LC-HAPF model, it can be deduced that adding the dc-link voltage control signal as an instantaneous reactive component is more efficient than adding the dc-link voltage control signal as an instantaneous active component in controlling the dc-link voltage of the LC-HAPF. Moreover, in order to make the dc-link voltage control process become more effective, a start-up process for the LC-HAPF is introduced. Simulation results indicated the validity about the dc-link voltage control analysis. Finally an experimental prototype of low dc-link voltage 220V-10KVA Three-phase Four-wire LC-HAPF for reactive power, current harmonic and neutral current compensation is designed, built and tested. Based on the testing results, all the analyses and proposed solutions are verified.