Three-Phase Z-Source AC-AC Converter for Motor Drives

This paper presents a Z-source ac-ac converter system and control for general-purpose motor drives. The Z-source ac-ac converter system employs a unique LC network to suppress the over-current and surge voltage due to the shoot-through or the open-circuit of the two switches. By controlling the duty cycle, the Z-source can provide buck-boost function, produce greater or less voltage than the line voltage. As a result, the new Z-source ac-ac converter system provides ride-through capability under voltage sags, reduces line harmonics, and improves power factor and reliability. Analysis, simulation and experimental results will be presented to demonstrate these new features