SIMULATION OF A CLOSED SYSTEM OF A DC ELECTRIC DRIVE WITH A WIDTH-PULSE CONVERTER

This article investigates the regulation of the angular speed of an electric drive (ED) with a pulse-width converter (PWC) and a direct current motor (DC motor) of independent excitation (NV) when controlled in a closed-loop system. A proportional-integral (PI) -regulator was used as a regulator of the angular velocity. To analyze the processes in the closed-loop SHIP-DPT system, the methods of simulation are used. The principle of operation of an electric drive with control from a PWM is described. Developed and modeled EP circuits with PWM in the Matlab environment using blocks from the Simulink / SimPowerSystem library. A model block has been modeled that calculates the static and dynamic power losses of the PWP IGBT. To calculate the static and dynamic losses, the method of approximating the loss graphs was used. The obtained mathematical dependences describe quite accurately the graphs of the power losses of the IGBT transistor. It is shown that when using a PI-controller, the angular speed of the electric drive is set according to a given speed reference signal.

Flying Capacitor Inverter Integration in a Renewable Energy System

This chapter presents a three-cell flying capacitor converter photovoltaic (PV) system. This system consists of a DC-DC boost power converter connected in series with a multicell inverter. The perturb and observe MPPT technique has been used to extract the maximum power from the solar panel and generate the duty signal to control the switch of the DC-DC converter. The three-cell flying capacitor inverter ensures the conversion of the output voltage of the boost chopper to the alternative voltage. This topology is made up of hybrid association of commutation cells, which makes it possible to share the voltage constraint on several switches. A closed loop control based on PWM has been proposed to control the capacitor voltages of the inverter. The output current is controlled using a PI regulator. The aim of the proposed three cell inverter is to produce an approximate sinusoidal output current with a very low THD. The simulation results assess the effectiveness of the control.

Laboratory Stand for Simplified Verification of Missile Dynamics for Didactic Purposes

The purpose of this study was to describe dynamics of missile based on bibliography, simplify the model to the easiest form, and verify it with the use of a designed laboratory stand. Next, a simple control system of the missile was designed. The stand is prepared for didactic purposes. A mathematical model was derived by applying Newton's second law together with the earth's coordinate system and the base coordinate system. Parameters of the actual rocket model were determined using the created laboratory stand. Synthesis of the rocket roll system was designed using Simulink PID Tuner application (MathWorks, Inc. Natick, Massachusetts, USA). A control system was based on a proportional-integral (PI) regulator. The designed control system was subjected to simulated tests in MATLAB Simulink (MathWorks, Inc. Natick, Massachusetts, USA).

Performance improvement of the variable speed wind turbine driving a DFIG using nonlinear control strategies

In this research paper, a nonlinear Backstepping controller has been proposed in order to improve the dynamic performance of a doubly fed induction generator (DFIG) based Wind Energy conversion System, connected to the grid through a back-to-back converter. Firstly, an overall modeling of proposed system has been presented. Thereafter, three control techniques namely backstepping (BSC), sliding mode (SMC) and field-oriented control (FOC) using a conventional PI regulator have been designed in order to control the stator active and reactive powers of the DFIG. In addition, the maximum power point tracking (MPPT) strategy has been investigated in this work with three mechanical speed controllers: BSC, SMC and PI controller with the aim of making a synthesis and a comparison between their performances to determine which of those three techniques is more efficient to extract the maximum power. Finally, a thorough comparison between the adopted techniques for the DFIG control has been established in terms of response time, rise time, total harmonic distortion THD (%) of the stator current, static errors and robustness. The effectiveness and robustness of each control approach has been implemented and tested under MATLAB/Simulink environment by using a 1.5 MW wind system model.

Interval Type-2 Fuzzy Dynamic High Type Control of Permanent Magnet Synchronous Motor with Vector Decoupling Method

This paper presents an interval type-2 fuzzy dynamic high type (IT2FDHT) control based on vector decoupling method for permanent magnet synchronous motor (PMSM) to improve the dynamic characteristics of the system. Firstly, to address the shortcomings of the traditional PI regulator used in the current loop of PMSM, an improved PI regulator based on voltage feed-forward decoupling is used. Then, considering the characteristics that the higher the system type, the smaller the steady-state error and the shorter the regulation time, the high type control structure is added. However, a purely high type structure amplifies the oscillations of the system and is extremely sensitive to perturbations, which can easily lead to system divergence. Therefore, in order to solve the problems caused by high type structure, finally we designed dynamic high type control with the help of fuzzy logic systems (FLSs), which successfully achieved automatic switching of system type while improving response speed and steady-state accuracy. Meanwhile, quantum-behaved particle swarm optimization (QPSO) algorithm is employed to determine the parameters of FLSs. In summary, five methods including conventional PI, feed-forward decoupling PI (FDPI), FDPI high type (FDPI-HT), FDPI type-1 fuzzy dynamic high type (FDPI-T1FDHT), and FDPI-IT2FDHT, are compared to show the superiority of the proposed method. By means of simulations, the excellence of proposed FDPI-IT2FDHT is verified.

New Optimized Control of Cascaded Multilevel Converters for Grid Tied Photovoltaic Power Generation

This paper proposes a new optimized control of photovoltaic two stages conversion cascade composed by Three Levels Boost (TLB) and Three Levels Neutral Point Clamped (TLNPC) inverter. In order to extract the maximum power from photovoltaic generator and get a balanced DC bus voltage, the duty cycles of the two TLB switches are determinate from a Fuzzy Logic Controller (FLC) for the first switch and by adding to the first duty cycle an additional duty cycle obtained by integration of the error between the two capacitors voltages of DC bus. Balancing the bus voltages by the TLB using a single regulator avoid us to use a complex balancing algorithm by the redundant vectors of TLNPC inverter. For the control of the inverter, we used a Proportional Integral (PI) regulator optimized by PSO. This command allows us to have on one side a constant DC bus voltage and a current injection in phase with the grid voltage. To have an efficient follow-up of the TLNPC inverter reference voltages, the Space Vector Pulse Width Modulation (SVPWM) is applied. The simulation is carried out in MATLAB/SIMULINK platform. The results obtained from the application of the FLC command associated with PI PSO are better compared to the simulation without optimization in terms of sum of the absolute values of the errors at the inputs of the three PI regulators.

Improved Rotor Flux and Torque Control Based on the Third-Order Sliding Mode Scheme Applied to the Asynchronous Generator for the Single-Rotor Wind Turbine

In this work, a third-order sliding mode controller-based direct flux and torque control (DFTC-TOSMC) for an asynchronous generator (AG) based single-rotor wind turbine (SRWT) is proposed. The traditional direct flux and torque control (DFTC) technology or direct torque control (DTC) with integral proportional (PI) regulator (DFTC-PI) has been widely used in asynchronous generators in recent years due to its higher efficiency compared with the traditional DFTC switching strategy. At the same time, one of its main disadvantages is the significant ripples of magnetic flux and torque that are produced by the classical PI regulator. In order to solve these drawbacks, this work was designed to improve the strategy by removing these regulators. The designed strategy was based on replacing the PI regulators with a TOSMC method that will have the same inputs as these regulators. The numerical simulation was carried out in MATLAB software, and the results obtained can evaluate the effectiveness of the designed strategy relative to the traditional strategy.