Improved current regulation for voltage source inverters using zero crossings of the compensated current errors

This paper presents a consolidated strategy for closed loop current regulation of voltage source inverters by considering the zero crossings of the compensated (non-interactive) current errors. This approach leads to algorithms that can either vary a hysteresis bandwidth or directly modulate the phase leg switching times, and are implementable either with analogue hardware or digitally on a DSP. Two alternative approaches for generating the compensated current errors are presented. The merits and implementation of each scheme are examined and lead to a novel continuous switching delta current control scheme that minimises the current error, maintains a constant switching frequency with minimum harmonic generation, provides a rapid transient response and fully utilises the DC bus. The effectiveness of the consolidated control strategy has been verified by detailed simulation and experimental investigations.