A fast hysteresis current-controlled (HCC) permanent magnet synchronous motor (PMSM) drive based on field orientation is presented. The objectives of this research are to develop and utilize HCC algorithm for field orientation control (FOC) of a complete closed loop speed-controlled PMSM drive system, optimize the HCC algorithm to obtain fast speed response with step and ramp speed inputs to examine the effectiveness of current and torque tracking, identify the optimal control variables of the HCC on the PMSM, examine the performance with ramp and step reference speed inputs. The response of the developed model is compared with the speed response of the standard AC6 of MATLAB Simpower systems in terms of rise time, settling time and effectiveness of current and torque tracking. Compared to the standard AC6 of MATLAB Simpower systems, the developed model achieved rise time and settling time of 0.0108 seconds and 0.0143 seconds respectively while the corresponding values for AC6 model are 0.1944 seconds and 0.1984 seconds respectively. The developed model, therefore, offered superior performance over the AC6 model in terms of rise time, settling time and tracking capability.

A comprehensive comparison of the dynamic and steady state performance characteristics of permanent magnet synchronous motors (PMSM) with interior and surface rotor magnets for line-start operation is presented. The dynamic model equations of the PMSM, with damper windings, are utilized for dynamic studies. Two typical loading scenarios are examined: step and ramp loading. The interior permanent magnet synchronous motor (IPMSM) showed superior asynchronous performance under no load, attaining faster synchronism compared to the surface permanent magnet synchronous motor (SPMSM). With step load of 10 Nm at 2 s the combined effect of the excitation and the reluctance torque forced the IPMSM to pull into synchronism faster than the SPMSM which lacks saliency. The ability of the motors to withstand gradual load increase, in the synchronous mode, was examined using ramp loading starting from zero at 2 s. SPMSM lost synchronism at 12 s under 11 Nm load while the IPMSM sustained synchronism until 41 seconds under 40 Nm load. This clearly suggests that the IPMSM has superior load-withstand capability. The superiority is further buttressed with the steady state torque analysis where airgap torque in IPMSM is enhanced by the reluctance torque within 90E to 180E torque angle.

Abstract:A high performance hysteresis current control of a permanent magnet synchronous motor (PMSM) drive is developed in this paper. The core advantage of field orientation control (FOC) is utilized to separate the flux and torque control components of the stator current of the PMSM. Specifically, the objectives of this work are to develop and utilize the HCC algorithm for FOC of a complete closed-loop speed-controlled PMSM drive system, optimize the control algorithm to obtain fast speed response while maintaining effective current and torque tracking, and examine the hysteresis current control action clearly showing the inverter switching and the effects of hysteresis band selection. Being a speed-controlled system, the suitability of the developed model with constant, step, and ramp reference speed inputs is examined. The results obtained show that the developed model and algorithm based on hysteresis current control offer effective current and torque in all scenarios tested.

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In this paper, a new grid tied short-through proof solar photovoltaic (PV) inverter that is short-through proof is presented. Detailed presentation of this new solar inverter is preceded by a brief explanation of the generalized solar PV inverter, its types and some representative grid tied solar inverters (mainly micro-inverters) that are currently trending in the solar PV power conversion industry. The merits of each of these briefly explained solar inverter types and power circuits are emphasized. The new grid tied galvanic isolated solar inverter power circuit is then explained in detailed, analyzed and the steady state time varying circuit voltages and currents given. In addition to being short through proof, the new grid tied solar inverter is scalable from solar PV micro-inverter to solar PV central inverter in output power capability unlike the conventional grid-connected single phase inverters.