Variable speed drives (VSDs)‐based direct photovoltaic (PV) fed water pumping systems (WPS) are of increasing importance for the socio‐economic growth in remote areas. Due to the absence of windings and magnets on the rotor, switched reluctance motor (SRM) is emerging as a viable economic alternative in VSD systems. Thus, this study proposes and presents a simplified pulse width modulation‐based maximum power point tracking (MPPT) control for direct PV‐fed SRM‐WPS using modified lookup table (MLUT) approach. The proposed control technique offers lesser phase peak, near same phase rms, reduced torque ripple and noise, better efficiency and reduced DC‐link current ripple in contrast to single pulse mode technique. In addition, the proposed system does not require an intermediate converter and current sensors. Thus, results in reduced noise, reduced size and hence the cost of WPS. Further, it also provides a reduced memory size due to MLUT and an effective MPPT with the good dynamic response for a change in atmospheric conditions. The proposed system is modelled and simulated in MATLAB/Simulink environment and the prototype is built to validate experimentally using field programmable gate array controller. The performance analysis of the proposed system has been carried out and presented.
This study proposes a novel space-vector pulse width modulation scheme for an induction motor with open-end windings. The proposed PWM scheme requires two two-level inverters with isolated power supplies. This PWM scheme uses instantaneous phase reference voltages for the generation of gating signals. Open-end winding induction motor (OEWIM) offers significant switching redundancy. Thus, with the proposed scheme the required gating pulses can be generated to reduce the voltage stress on the switching devices. In addition, the switching scheme is capable of equalising the junction temperature rise during the switching and conduction state of the devices. In the present switching scheme when one inverter is switching while the other inverter is clamped and vice versa. The proposed scheme is simulated using MATLAB/Simulink. The PWM scheme is experimentally validated on dSPACE for a threelevel OEWIM.
This paper presents a single-stage solar photovoltaic (SPV) fed light-emitting diode (LED) street lighting system (LED-SLS) using a novel soft-switched buck-boost bidirectional DC-DC converter (BDC). A coupled inductor (CI) based auxiliary circuit is used in the proposed BDC to achieve soft switching, which leads to improved efficiency with reduced ripple. As SPV power is available during day time alone, a battery storage system (BSS) is used. The BSS is charged from SPV during day time through the proposed CI-BDC. The BSS powers the LED-SLS during night time through the same CI-BDC. The proposed CI-BDC provides various advantages like buck/boost operation in either direction of power flow, zero voltage switching (ZVS) soft-switching, use of single magnetic core, high efficiency, reduced ripple in output current, and simple control. Also, it provides an illumination control of the LED-SLS using pulse-width modulation (PWM) dimming. To maintain high efficiency even at light loads, the proposed CI-BDC works as conventional BDC by turning OFF the auxiliary circuit. Thus, avoiding the high conduction losses in it at light loads. The detailed working principle and design analysis are presented along with simulation results. A prototype of 40 W LED lighting system has been developed, and experimental validation is presented.
KEYWORDSbidirectional, buck-boost, coupled inductor, LED driver, soft switching 1990
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