Simple control strategy for balancing the DC-link voltage of neutral-point-clamped inverter at low modulation index

A Method for the Suppression of Fluctuations in the Neutral-Point Potential of a Three-Level NPC Inverter With a Capacitor-Voltage Loop

“…According to (2), (10) In order to clarify the impacts of the modulation index and load power factor on the NPP fluctuation, an analysis of the three-level NPC inverter supplying a three-phase symmetrical RL load is made here. It is assumed that the load power factor is constant cos 0.866 (a) m=0.533 Regarding the impact of the load power factor, it is assumed that m=1, the phase impedance phase 6.…”

Direct dead-time control - a novel dc-link neutral-point balancing method for the three-level neutral-point-clamped voltage source inverter

“…00+) part of the neutral-point currents. Moreover, it can be noticed that the redundant switch states of the small vectors drive the neutral-point voltage in opposite directions [10], [1], [2]. The space vector based methods to control the neutral-point are based on the variation of the distribution of the duty cycle of the small vectors.…”

“…The space vector based methods to control the neutral-point are based on the variation of the distribution of the duty cycle of the small vectors. The suitable selection of the small vectors allows the neutral-point balancing [2], [10]. Basically, carrier based methods add a common mode dc-offset to the references of the voltages in order to control the neutral-point voltage without affecting the line-to-line output voltages [10], [12], [4], [3].…”

Model predictive current control of DSTATCOM with simplified weighting factor selection using VIKOR method for power quality improvement

“…The distinct leakage currents, asymmetrical charging of dc-link capacitors during compensation of loads with higher unbalance factor initiate voltage unbalance across the capacitors of TPSC topology, which deteriorate the DSTATCOM performance [18,19]. In the literature, the switching of the inverter is adjusted to overcome this limitation; however, it further increases the control complexity [19][20][21]. As mentioned that, the advantage of MPC is, easy inclusion of control parameters; therefore, the voltage unbalance problem can be eliminated by taking the difference between capacitor voltages as an additional control parameter and it is added to the cost function using a weighting factor.…”