A photovoltaic-fed z-source inverter motor drive with fault-tolerant capability for rural irrigation

In recent years, photovoltaic (PV) systems have emerged as economical solutions for irrigation systems in rural areas. However, they are characterized by low voltage output and less reliable configurations. To address this issue in this paper, a promising inverter configuration called Impedance (Z)-source inverter (ZSI) is designed and implemented to obtain high voltage output with single-stage power conversion, particularly suitable for irrigation application. An improved and efficient modulation scheme and design specifications of the network parameters are derived. Additionally, a suitable fault-tolerant strategy is developed and implemented to improve reliability and efficiency. It incorporates an additional redundant leg with an improved control strategy to facilitate the fault-tolerant operation. The proposed fault-tolerant circuit is designed to handle switch failures of the inverter modules due to the open-circuit and short-circuit faults. The relevant simulation and experimental results under normal, faulty and post-fault operation are presented. The post-fault operation characteristics are identical to the normal operation. The motor performance characteristics such as load current, torque, harmonic spectrum, and efficiency are thoroughly analysed to prove the suitability of the proposed system for irrigation applications. This study provides an efficient and economical solution for rural irrigation utilized in developing countries, for example, India.