Space vector modulation and control of a unidirectional three-phase/level/switch VIENNA I rectifier with LCL-type AC filter

This paper presents a novel three-level space vector modulation method applied to a vector controlled VIENNA I rectifier with LCL-type AC filter. The principle modulation algorithm operation, basic assumptions and restrictions due to the main circuit are analysed in case of conventional L filter. Then the analysis is extended to include the LCL filter. On the basis of the key equations derived from the system examined, the vector control system is realised. The theoretical analysis of the proposed modulation technique and vector control system is verified by Simplorer and Matlab Simulink simulations, taking into consideration the total harmonic line current distortion, the losses in the active and passive components, delays and switching transients of the semiconductor devices. The rectifier system is designed to operate at a nominal DC link output power of 50kW, DC link voltage 650V and applied switching frequency 3.5kHz. The LCL filter is designed so that the total harmonic line current distortion is 1% while the rectifier current distortion is 4%.