Analysis and Proposal of Capacitor Voltage Control for an Asymmetric Cascaded Inverter

Single-phase distributed generation system based on asymmetrical cascaded multilevel inverter

“…The lowest voltage cell (22.95V) operates with a 3-level PWM modulation strategy to cover all the possible voltage range among levels and to reduce the voltage error. The highest and middle voltage cells operate at low switching frequency with a special modulation strategy presented in (Lipo & Manjrekar, 1999;Pimentel, 2006;Rech & Pinheiro, 2005;Silva et al, 2005a).…”

“…Others are related to power quality and conducted EMI. The main disadvantages of the used multilevel inverter are: many switching devices; the DC voltages should be isolated from each other; the DC voltage value of the highest voltage Hbridge cell rises rapidly if the numbers of levels increases fairly; and its control system and www.intechopen.com modulation strategy are not simple (Rech & Pinheiro, 2005;Silva et al, 2005a). However the asymmetrical topology produces an output voltage v c waveform with lower THD than the standard PWM 3-level inverter.…”

Cascaded two level inverter based grid connected photovoltaic system: Modelling and control

“…The variations of output voltage of photovoltaic systems are usually controlled by dc-dc converters, connected with the link capacitors. Various control strategies are available in literature to control the converters [7], [8], and [9]. In this paper, however, one control technique is proposed to keep the dc link voltages constant for the isolated sources by balancing the active power flow.…”

A 6.6‐kV transformerless cascade PWM STATCOM. Experimental verification by a three‐phase 200‐V, 10‐kVa laboratory system

“…Therefore, a transformerless STATCOM based on a multilevel converter would be preferable. In a STATCOM [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] that uses cascade connections [1] to a single-phase voltage-type converter, the number of steps can be more easily extended compared to a STATCOM [21] using a diode clamp-type converter. However, regulating the imbalance in the voltage of several independent DC capacitors is difficult.…”