Abstract:

With the rapid development of new energy generation, the issue of intermittency and uncertainty in the output power of new energy generation is becoming increasingly prominent. In order to enhance the grid's ability to absorb new energy, a type I three level energy storage converter has been designed. On the basis of in-depth analysis of its working principle, a mathematical model was constructed and a constant current charging and discharging control strategy was provided. In response to the problem of midpoint potential imbalance in the three level energy storage converter, a space vector pulse width modulation (SVPWM) algorithm with variable distribution factor was proposed to achieve rapid response to midpoint potential fluctuations. The experimental results of prototype show that under constant current charging and discharging control strategy, the designed prototype has good steady-state and transient performance under grid connection conditions. The used SVPWM algorithm with variable allocation factor can quickly suppress midpoint potential fluctuations and has a significant inhibitory effect.

Key words: new energy, three-level energy storage converter, midpoint potential balance control, space vector pulse width modulation(SVPWM)