The permanent magnet synchronous motor (PMSM) driven by an inverter is widely used in the industrial field, but the inverter has a significant impact on the operational stability of the PMSM. The torque ripple of the PMSM is directly affected by the coupling of multiple harmonic voltages in the motor windings. In order to analyze its influence, a water-cooled PMSM with 20 kW 2000 r/min is taken as an example to establish the finite element model of the prototype, and the correctness of the model is verified by experiments. Firstly, based on the finite element method, the electromagnetic field of the PMSM is numerically solved in different operating states, and the performance parameters of the PMSM are obtained. Based on these parameters, the influence of the harmonic voltage amplitude on the torque ripple is studied, and the influence law is obtained. Secondly, combined with the decoupling analysis method, the influence of harmonic voltage coupling on the torque ripple is compared and analyzed, and the variation law of harmonic voltage coupling on the torque ripple is obtained. In addition, the influence of different harmonic voltage coupling on the average torque of the PMSM is studied, and the influence degree of different harmonic voltage amplitude on the torque fluctuation is determined. The conclusion of this paper provides reliable theoretical guidance for improving motor performance.
Many parts of remote locations in the world are not electrified even in this Advanced Technology Era. To provide electricity in such remote places renewable hybrid energy systems are very much suitable. In this paper PV/Wind/Battery Hybrid Power System (HPS) is considered to provide an economical and sustainable power to a remote load. HPS can supply the maximum power to the load at a particular operating point which is generally called as Maximum Power Point (MPP). Fuzzy Logic based MPPT (FLMPPT) control method has been implemented for both Solar and Wind Power Systems. FLMPPT control technique is implemented to generate the optimal reference voltage for the first stage of DC-DC Boost converter in both the PV and Wind energy system. The HPS is tested with variable solar irradiation, temperature, and wind speed. The FLMPPT method is compared with P&O MPPT method. The proposed method provides a good maximum power operation of the hybrid system at all operating conditions. In order to combine both sources, the DC bus voltage is made constant by employing PI Controllers for the second stage of DC-DC Buck-Boost converter in both Solar and Wind Power Systems. Battery Bank is used to store excess power from Renewable Energy Sources (RES) and to provide continuous power to load when the RES power is less than load power. A SPWM inverter is designed to convert DC power into AC to supply three phase load. An LC filter is also used at the output of inverter to get sinusoidal current from the PWM inverter. The entire system was modeled and simulated in Matlab/Simulink Environment. The results presented show the validation of the HPS design.
An integrated Z-source inverter for the single-phase single-stage grid-connected photovoltaic system is proposed in this paper. The inverter integrates three functional blocks including maximum-power-point-tracking, step-up/down DC-side voltage and output grid-connected current. According to the non-minimum-phase characteristic presented in DC-side and the functional demands of the system, two constant-frequency sliding-mode controllers with integral compensation are proposed to guarantee the system robustness. By using two controllers, the effects caused by the non-minimum-phase characteristic are mitigated. Under the circumstance of that the input voltage or the grid-connected current changes suddenly, the notches/protrusions following the over-shoot/ under-shoot of the DC-bus voltage are eliminated. The quality of grid-connected current is ensured. Also, a small-signal modelling method is employed to analyze the close-loop system. A 300W prototype is built in the laboratory. A solar-array simulator (SAS) is used to verify the systematic responses in the experiment. The correctness and validity of the inverter and proposed control algorithm are proved by simulation and experimental results.
The problem of mathematical modelling and indication of properties of a DIP has been investigated in this paper. The aim of this work is to aggregate the knowledge on a DIP modelling using the Euler-Lagrange formalism in the presence of external forces and friction. To indicate the main properties important for simulation, model parameters identification and control system synthesis, analytical and numerical tools have been used. The investigated properties include stability of equilibrium points, a chaos of dynamics and non-minimum phase behaviour around an upper position. The presented results refer to the model of a physical (constructed) DIP system.