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 (noninteractive) 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.