Harmonic Current Compensation Using Constant DC-Capacitor Voltage-Control-Based Strategy of Three-Level Neutral-Point-Clamped Inverter-Based STATCOM with Reactive Power Control

抄録

This paper proposes a constant dc-capacitor voltage-control (CDCVC)-based reactive power control strategy of a static synchronous compensator (STATCOM) with a three-level neutral-point-clamped (NPC) inverter, in which the source-side harmonic currents are also compensated. The CDCVC-based reactive power control strategy uses only a CDCVC, which is always used in the grid-connected inverters, STATCOMs etc. Calculation blocks of fundamental active, reactive, and harmonic components are not needed. Thus, the authors offer a simplified strategy for a source-side reactive power control with source-side harmonic current compensations. The instantaneous power flowing into the STATCOM with a three-level NPC inverter is discussed in detail. The instantaneous power flow shows that using the CDCVC-based strategy for the STATCOM achieves sinusoidal source currents using the controlled source-side reactive power compensating the harmonic currents on the source side. A digital computer simulation is implemented to confirm the validity and high practicability of the CDCVC-based strategy. A reduced-scale prototype experimental model is constructed and tested. The simulation and experimental results demonstrate that sinusoidal source currents are obtained with the CDCVC-based strategy controlling the reactive power on the source side.