Abstract: The paper presents the design and parameter selection of main circuit of the shearer traction converter system, gives its circuit structure and the implementation of the system hardware and software based on DSP, realize the synchronous PI decoupling current control of 4-Quadrant Converter. Experiment results show that the system provides the steady DC voltage as well as the 1ow harmonic line current，unity power factor and bidirectional power flow．The 4-Quadrant Converter improve the reliability and traction performance of the shearer, meet requirements of AC traction frequency operation of the shearer.