An Improved T-type Switched-Capacitor Based 3-level 3-Phase Inverter with Common Mode Voltage Elimination and Voltage Boosting Capability

<p>Zero common mode voltage (ZCMV) space vector modulation (SVM) strategy applied to a three-phase multilevel inverter (MLI) eliminates the common mode voltage (CMV). However, the usage of ZCMV-SVM strategy reduces the number of levels in the output voltage and requires higher magnitude dc voltage source due to the reduced modulation depth of the employed PWM scheme. Moreover, the usage of a single dc-source in such systems may have issues with respect to capacitor voltage balancing. Taking into account all the above issues, a 3-level inverter solution is proposed in this manuscript. The complete details of the method used for developing the proposed solution using the ZCMV space vectors is also included in this paper. The proposed topology utilizes a unique combination of a T-type 3-level inverter and a switched-capacitor (SC) circuit to achieve ZCMV performance with a single dc-source of low magnitude at a reduced component count. Analysis of the CMV and terminal voltages along with the design of the SCs are presented in this paper. The proposed topology is compared with the existing topologies to prove its unique merits over the other 3LI solutions with ZCMV capability. All the claims are validated using simulation and experimental results.</p>

An Improved T-type Switched-Capacitor Based 3-level 3-Phase Inverter with Common Mode Voltage Elimination and Voltage Boosting Capability

<p>Zero common mode voltage (ZCMV) space vector modulation (SVM) strategy applied to a three-phase multilevel inverter (MLI) eliminates the common mode voltage (CMV). However, the usage of ZCMV-SVM strategy reduces the number of levels in the output voltage and requires higher magnitude dc voltage source due to the reduced modulation depth of the employed PWM scheme. Moreover, the usage of a single dc-source in such systems may have issues with respect to capacitor voltage balancing. Taking into account all the above issues, a 3-level inverter solution is proposed in this manuscript. The complete details of the method used for developing the proposed solution using the ZCMV space vectors is also included in this paper. The proposed topology utilizes a unique combination of a T-type 3-level inverter and a switched-capacitor (SC) circuit to achieve ZCMV performance with a single dc-source of low magnitude at a reduced component count. Analysis of the CMV and terminal voltages along with the design of the SCs are presented in this paper. The proposed topology is compared with the existing topologies to prove its unique merits over the other 3LI solutions with ZCMV capability. All the claims are validated using simulation and experimental results.</p>

A Generalized Space Vector Modulation for Cascaded H-Bridge Inverters under Faulty Conditions

In this research, a new space vector modulation control algorithm is proposed to increase the reliability and the accuracy of the cascaded H-bridge multilevel inverters in case of faulty situations where one or several power cells do not function. When one or more switches of a cell are opened or shorted, that cell is considered faulty. By giving a detailed analysis on the impact of the faulty power cells on the voltage space vectors, the inapplicable voltage vectors are removed precisely. Consequently, the optimal redundant switching states are chosen such that the highest possible output voltage can be achieved. In addition, the balance of the three phases line-to-line voltage and current are maintained. The proposed algorithm is also generalized so that it can be applied to any level of H-bridge inverters. The validity of the method is verified by numerical simulations using MATLAB Simulink with an 11-level cascaded H-bridge inverter.

Vector control strategy of the five-phase VSI

The paper describes an example of the vector control strategy applied to five-phase two-level inverters. Two base methods are discussed. The first one is based on the standard space vector transformation, while the other uses state vectors which enable the definition of the basic physical quantities of the inverter. The proposed notation system offers an universal simplification of vector identification. It comprises a standardized proposal of notation and vector marking. This tool may be really useful for the description of inverter states and makes it possible to reach correlation between state and space vectors. All vectors are defined by use of the same digits. The proposed mathematical tool has been verified during simulation tests performed with the use of the PLECS program.