Grid fault ride-through in matrix converters for adjustable speed drives

Abstract

A novel ride-through approach for matrix converters in adjustable speed drives is presented, utilizing the input filter capacitors as an energy transfer mechanism to support motor flux during grid fault events. The addition of three bi-directional switches is required to isolate the input filter capacitors from the collapsed grid voltages. The additional input switches, a new ride-through vector control strategy, and the post fault reconnection logic are shown to enable ride-through of many cycle faults without the use of an additional energy storage devices. The proposed architecture is verified in theory, simulation, and hardware.The architecture is valid for both indirect and direct matrix converters, provides full bi-directional power flow, and requires no additional reactive components. Additional benefits include reduced in-rush current, reduced transient voltage overshoot at plug-in, reduced damping losses, and potential harvesting of energy from remaining active grid phases.To support the work, a review of power quality assessments is included. Through this review it is shown that the proposed architecture allows matrix converter-based adjustable speed drives to successfully operate in >95% of grid fault events.