Arm cortex M4 microprocessors based ± 100 kVAR energy quality regulator for reactive power/neutral current compensation, load balancing and harmonic mitigation

Abstract

In this work, the design and implementation of a three-phase ± 100 kVAR energy quality regulator (EQR) which is capable of providing reactive power/neutral current compensation, load balancing as well as low order current harmonic mitigation is presented. The proposed EQR is based on three-leg four-wire voltage source converter topology with split capacitors in the DC link. At first, the power stage and the control system of the EQR are modelled and verified in PSCAD/EMTDC by extracting the compensation reference currents in synchronous reference frame. After that, the hardware of the EQR based on naturel air forced IGBT modules switching at 5 kHz is developed and practically implemented. The developed EQR control card is based on two Arm Cortex-M4 microprocessors © which handles all control and protection functions. Closed loop operation of the EQR is ensured with P, PI and PR type controllers due to their simplicity and reliability in practical applications. The field tests in a 50 Hz live distribution circuit are carried out by connecting the EQR to the low voltage side of a three-phase 34.5/0.4 kV 400 kVA distribution transformer. It is verified by real-time measurements that the EQR is able to perform the aforementioned compensation functions simultaneously.