Voltage Balancing Svpwm Algorithm For Diode-Clamped Multileve Statcom

Multi-level inverter has been widely used in power quality, power transmission frequency control and new energy technologies etc. This technology has become one of the important research orientations in the power electronics technology. Nowadays, the study of voltage balancing for Diode-clamped three-level inverter has been relatively mature. However, for the high number lever inverter, with the increase of support capacitors, the voltage balancing control is more difficult. In this paper, to solve the problem of support capacitors voltage unbalancing in the diode-clamped five-level inverter, the research works are as follows.First, analysis the causes of support capacitors voltage unbalancing of the diode-clamped five-level inverter and different effects to the voltage of capacitor while transmission active power and reactive power. While inverter in different switching state, the capacitance charge and discharge time is also different, that causes voltage unbalancing. By selecting the appropriate redundant space vector, a voltage balancing Space Vector Pulse Width Modulation algorithm was given. This algorithm can well realize the capacitor voltage balancing control within a certain range.Then, voltage balancing SVPWM algorithm was using in the diode-clamped five-level STATCOM system, STATCOM control system design was introduction as well. The simulation verified the reliability of the algorithm in STATCOM system to ensure the voltage balancing. By having compared with the SPWM and tradition SVPWM modulation method, further verification the algorithm guarantee the effectiveness of the voltage balancing.Last, the experiment design of FPGA-based systems was given. Including, the implementation of voltage balancing SVPWM algorithm and STATCOM control system. In order to verify the reliability of the SVPWM algorithm, the experiment of Diode-clamped five-level three-phase rectifier was established and the pre-experiment was studied. The main experimental results are two-level three-phase STATCOM, five-level STATCOM based on SPWM and voltage balancing SVPWM.