Research On Power Quality Of Ship Electric Propulsion System Based On Matrix Convertor

The AC converter of the ship electric propulsion system has the AC-AC converter and the AC-DC-AC converter,but both have serious disadvantages such as serious harmonic pollution and low power factor.The matrix converter has good input and output characteristics,DC energy storage element is not needed,and input power factor always is 1 and so on.So it has a good application prospect in the frequency conversion system of ship propulsion motor.Therefore,it is very important to study the working principle and application of matrix converter from the aspects of matrix converter principle and modulation strategy,motor vector control and power quality analysis.The main contents are included as following:1)Research on the working principle of matrix converter,analysis of dual space vector modulation(dual SVPWM-Space Vector Pulse Width Modulation)theory,in Matlab / Simulink set up a matrix converter and its modulation circuit simulation model,simulation experiments,The experimental results show that the input and output characteristics of the matrix converter and the adjustable power factor are good.2)The principle of vector control of PMSM-Permanent Magnet Synchronous Motor is studied,and the vector control system of ship permanent magnet synchronous motor based on AC-DC-AC converter and matrix converter is established,and the two systems are simulated and analyzed comparatively.The experimental results show that the electromagnetic torque and the load torque of the two systems are well followed,and the system response is fast and smooth,and the vector control characteristics are realized.3)The ship electric propulsion system based on AC-DC-AC converter and matrix converter is established by the China Railway Bohai Railway ferry as the mother ship.Based on the different working conditions,the PMSM vector control system is used,and the harmonic problem of the electric propulsion system based on two converters is compared and analyzed respectively.The experimental results show that the matrix converter is better than the AC-DC-AC converter in the electro-push system,and can achieve good vector control under different working conditions.Moreover,the AC-DC-AC converter has better input and output characteristics,the input voltage harmonic distortion rate is lower.