1. Masterless Interleaving Scheme for Parallel-Connected Inverters Operating with Variable Frequency Hysteretic Current-Mode Control
- Author
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Olivier Trescases, Mojtaba Ashourloo, Miad Nasr, and Samantha K. Murray
- Subjects
Interleaving ,Computer science ,Automatic frequency control ,0211 other engineering and technologies ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Inductor ,Power (physics) ,Control theory ,Harmonics ,Inverter ,Digital control ,021108 energy ,0210 nano-technology - Abstract
This paper describes a new masterless interleaving scheme for parallel sub-inverters operating in variable frequency Hysteretic Current-Mode Control (HCMC). The proposed digital control scheme enables the development of fault-tolerant, modular, efficient, and power dense inverters. A feed-forward controller is used to instantaneously correct for phase error at each switching cycle, while a compensator corrects for the systematic difference in sub-inverter switching frequencies caused by inductor mismatch. The control is verified by simulation up to 2 kW in an inverter system consisting of three parallel sub-inverters. Experimental results are presented for the same system operating in Boundary Conduction Mode (BCM) at 895 W. Activation of the interleaving controller shows a reduction in peak current into the system EMI filter, while maintaining the soft-switching benefits of BCM operation. The proposed interleaving scheme reduces the magnitude of the lowest switching frequency harmonics by a peak of 35 dB and an average of approximately 10 dB, which is demonstrated by comparing the inverter system’s current spectrum with and without interleaving.
- Published
- 2019