A Limited Common-Mode Current Switched-Capacitor Multilevel Inverter Topology and Its Performance and Lifetime Evaluation in Grid-Connected Photovoltaic Applications

Abstract

In this paper, a switched-capacitor multilevel inverter with voltage boosting and common-mode-voltage reduction capabilities is put forth. The proposed inverter is synthesized with one-half bridge and several switched-capacitor cells. Due to the voltage boosting and common-mode current reduction features, the proposed multilevel inverter is suitable for grid-connected PV applications. In addition, an analytical lifetime evaluation based on mission profile of the proposed inverter has been presented to derive lifetime distribution of semiconductors. Whereas in the proposed inverter, any components failure can bring the whole system to a shutdown. The series reliability model is used to estimate the lifetime of the overall system. The performance of the suggested multilevel inverter in grid-connected applications is verified through the simulation results using the grid-tied model in Matlab/Simulink. Moreover, the viability and feasibility of the presented inverter are proven by using a one kW lab-scaled prototype.

A switched‐capacitor multilevel inverter topology employing a novel variable structure nearest‐level modulation

“…Moreover, the voltage boosting is also lower than the proposed topology. Voltage boosting in Reference 32 is higher than the proposed MLI.…”

An Improved Overmodulation Strategy for a Three-Level NPC Inverter Considering Neutral-Point Voltage Balance and Common-Mode Voltage Suppression

“…The traditional SVPWM method and VSVPWM method considering common-mode voltage rejection in [28] are adopted for comparison. As shown in Figure 7a, when the SVPWM method is adopted, the magnitude of the leakage current reaches 400 mA, which fails to comply with the standard level of 300 mA [29]. When the other two methods are adopted, the magnitude of the leakage current is limited effectively within the 300 mA.…”

“…Shaft voltage and bearing current will be generated by the common-mode voltage (CMV), which may destroy the motor insulation in motor drive applications and increase the leakage current in the distributed generation applications [22][23][24][25]. Virtual space vector PWM (VSVPWM) provides a new idea for the NP voltage control and the CMV suppression [26][27][28][29][30][31][32][33]. A novel VSVPWM considering NP voltage balance and CMV suppression is proposed in [23].…”

“…In [26], a control strategy to realize the asymmetric control of the DC-bus voltages with VSVPWM is studied. In [29], a switched-capacitor multilevel inverter with voltage boosting and CMV reduction capabilities has been studied. In [31], a novel modulation method has been proposed to reduce the CMV and balance the NP voltage and apply to the line voltage coordinate system.…”

A Generalized Switched-Capacitor Multilevel Inverter Topology with Voltage Boosting Ability and Reduced Inrush Current

“…Thus, switched-capacitor inverters are commonly accepted. The switched-capacitor inverters were created as a result of a topology described in [4][5][6]. Many more topologies have emerged in the case of switched-capacitor MLIs [7][8][9][10][11].…”