Networked PFC drive for SPPSCIM air conditioners to enable elastic load operation in constrained power systems

Large HVAC systems are good candidates for elastic loads in demand side management optimization of smarter grid infrastructures. There is an increaseing trend of using Split-type Air Conditioners (ACs) in residential, commercial and industrial setups for fine granularity temperature control. The traditional control in each unit is through duty-cycle based hysteretic method which is simple but inefficient and requires power spikes at every start-up of the compressor. In developing countries with weak grids, people rely on backup sources like generators and UPS. Large power surge at each turn-on inflicts huge pressure on these constrained resources. Limited work has been reported that aims at energy optimization and controlled operation of Split-type ACs constructed using single phase permanent split capacitor induction machine (SPPSCIM). Our work targets operational optimization, efficiency enhancement and increased load handling capability of contrained power systems in setups employing multiple AC units. This is done through networked Variable Frequency Drives (VFD) for conventional ACs which allow elimination of surge current at turn-on and tighter set-point control while drawing sinusoidal current near unity power factor from the constrained source. Furthermore, the networked operation allows integration of existing installed base of standalone units through Building Management System (BMS) with the central control infrastructure. The prototype networked VFD is tested on a 2.3kW Mitsubishi Electric Split-type AC through Wi-Fi and the results are presented to confirm the expected results in network mode of operation.