Experimental Investigation on Ride through Capability of Closed Loop Controlled Matrix Converter Fed Cage Drive

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Three phase matrix converters have received considerable attention in recent years because they may become a good alternative to voltage-source inverter pulse widthmodulation (VSI-PWM) converters. In fact, the matrix converter provides bidirectional power flow, sinusoidal input/output waveforms, and controllable input power factor. Furthermore, the matrix converter allows a compact design due to the lack of dc-link capacitors for energy storage. The matrix converters are more sensitive to input power disturbances than conventional PWM voltage source inverters due to the absence of dc-link. With the rapid increase of adjustable speed drives (ASDs) in commercial and industrial facilities, the susceptibility of ASDs under power disturbances such as sags, swells, transients and short term power interruption (STPI) has become more important issue. A matrix converter laboratory prototype of 250 VA, 230 V capacity has been developed with the embedded PWM VSI part, to investigate the ride through capability. The ride through approach has been shown to maintain the rotor flux and keep synchronization between the motor and matrix converter during momentary power interruption. It has been shown that by regenerating the mechanical energy stored in load inertia and transferring it to dc-link capacitor within the embedded PWM VSI part, successful ride-through operation is accomplished. The duration of the ride-through operation depends on initial motor shaft speed level, load torque type and load inertia and so the approach is more effective for applications with sufficient load inertia. The ride-through capability has been achieved by the minimal addition of hardware and software into the matrix converter.Energy efficient data transfer is the key factor for the design of energy efficient wireless sensor network (WSN). In this paper, an energy efficient cooperative MIMO (C-MIMO) technique is proposed in the WSN where fixed constellation size is considered in transmitting both the local and long-haul communication. A selection criterion is used based on the channel conditions where a selected number of sensors in a cluster is used to form a multiple input multiple output (MIMO) structure wirelessly connected with multiple antennas of a data gathering node (DGN). The selected approach is tested on the correlated data scenario. Experimental results show that the selected C-MIMO structure outperforms the unselected C-MIMO in terms of total energy consumption and they show energy efficient performance over existing one when they are compared with SISO structure. Energy models are evaluated for this scenario while energy consumption and efficiency are compared for different combination of cluster sizes and selected number of sensors. Comparisons are shown for different fixed number of constellation sizes. The effect of correlation coefficient and intersensor distance are analyzed. Later, a delay analysis is shown considering optimal constellation size.