Active and reactive power compensation of Data Center using Multi-Level STATCOM Inverter

Abstract

Data Center (DC) is one of the largest and fastest growing consumers of electricity in the world. In 2013, US DCs consumed an estimated 91 billion kWhr of electricity - enough electricity to power all the households in NY City twice over - and are on-track to reach 140 billion kWhr by 2020 [1]. Paper presents development of ‘Multi-Level Static Synchronous Compensator Inverter’ (MLSTATCOMI) for DC application using Space vector PWM (SVPWM) based digital controller at Medium Voltage (MV) application. MV operation reduces overall electrical losses and reduces Power Usage Effectiveness (PUE) of DC. Reactive power STATCOM compensator along with battery energy storage provides active power compensation also. Capacitor voltage balancing of ML inverter is not an issue with reactive power STATCOM compensator as active power transfer is almost zero. Capacitor voltage balance depends on net transfer of active power between Inverter DC-link voltage source and AC grid source [2]. Capacitor voltage balancing is an issue of MLSTATCOMI compensator as it needs to compensate both active and reactive power. DSP and FPGA based SVPWM digital controller is developed to compensate simultaneous active and reactive power compensation. ML capacitor voltage balancing is achieved by developing a unique switching sequence of Inverter space vectors. The modulator performance using SVPWM control strategy can be extended to five-level inverter using space vector [3] for DC application.