Discrete pulse modulation strategies for high-frequency inverter systems

High-performance high-frequency inverter systems for UPS (uninterruptible power supply) applications represent a demanding application which cannot easily be realized using conventional hard-switched PWM (pulse-width-modulated) inverter topologies. Adoption of typical soft-switched inverters such as the resonant DC link inverter requires the use of discrete pulse modulation strategies. New controller structures are necessary to cope with stringent voltage regulation and distortion constraints in the presence of unbalanced and nonlinear loads. A controller is presented which utilizes a load-current feedforward strategy with a cost function current regulator to achieve excellent transient performance characteristics. Voltage regulation is ensured using a synchronous frame regulator. Detailed simulation results are presented.<
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