Design and stability analysis of a high-performance three-phase inverter for photovoltaic applications

The paper discussed the design of low cost inverter using SG3525A IC and IRF3205 MOSFET in H-Bridge configuration. The implementation of the real construction involved the use of IC SG3525A for generation of output pulses; the totem pole arrangement of transistors was used in the driver section of the inverter to boost signals as well as switching purposes. The H-bridge configuration was employed to effectively switch the four MOSFETs, this switching produced an alternating potential of 220V. Pre-set conditions such as load condition, low battery cut, overcharge cut and constant output were set at 1700W, 10V, 13.3V and 220V respectively so as to ensure effective and long lasting usage of the inverter. The battery used for the operation of the inverter was 12V maintenance free battery in order to reduce the cost of using the inverter. The various tests carried out on this inverter were tests on inductive loads, resistive loads, home appliances, overload condition, low battery and charging control. The aim of this work is to achieve inverter design analysis under resistive loads and inductive loads for efficient power usage at lowest possible cost. This was achieved by connecting various resistive and inductive loads on the inverter. The results show that the system can operate under both the resistive and inductive loads but operates better under resistive loads, the reason for this is that inductive loads always draw large currents during start-ups which always result to power losses. Graphs were plotted and analyzed; the results also showed that this inverter can take up to 1700W of resistive load and inductive load of 1020W. The inverter produced no humming sound from inductive loads and home appliances such as fan, television, refrigerator e.t.c that were within its maximum capacity of 1700W.

This paper presents a modified sinusoidal pulse width modulation (SPWM) switching method for one-phase and investigated two-phase impedance-source inverter structures. The proposed structure generates pulses for a quasi- Z-source converter and this block produces a unilateral voltage sine wave in the block's output. This signal is applied to the inverter as its input wave. For this purpose, the novel SPWM method is proposed for power switches while being switched complementarily. Two power switches are used in the structure to generate the pure sinusoidal output voltage and to minimize total harmonic distortion (THD), which is an essential parameter in inverter design. The results show that the proposed method generates the pure sinusoidal voltage and current signals for resistive and inductive loads and pure voltage and improved current waves for capacitive loads in comparison with existing techniques, since the THD of the output voltage and current signals is strongly affected by the dynamic loads. This method leads to final cost improvement and reduction of the size of the system with fewer number of components, which are essential parameters for renewable energy resource applications. A mathematical model is validated with the 2017a version of MATLAB/Simulink and 1.51% and 1.33% THD values are reported for low and high power loads, respectively, in the one-phase structure and 0.95% and 0.87% in the two-phase system. Finally, a 120 W prototype has been implemented and tested. A sine-wave with 620 Vac peak to peak amplitude and 50 Hz frequency has been gained in the inverter?s output and the quality of the voltage and current waveforms has been evaluated for different two 1.8 k$\Omega$ and 600 $\Omega$ resistive loads in the one-phase structure. Experimental results confirm all mathematical and simulation results.

DC/AC inverter topologies having reduced numbers of switches to reduce costs, total inverter size and switching losses have previously been proposed. In addition, these topologies reduce the likelihood of semiconductor switch damage, and have lower common-mode currents. This paper proposes new designs for inverters with reduced switch numbers. For three-phase systems, the proposed inverters use four switches instead of the six used in the traditional three-phase Voltage Source Inverter (VSI). Compared to the traditional Four-Switch Three-Phase (FSTP) inverter, the proposed FSTP inverters improve the voltage utilisation factor of the input dc supply, without the need for triplen injection. Sliding-mode control is used to demonstrate the dynamic response and robustness of the inverters. Also the paper presents new single-phase inverters with two switches instead of the four used in the traditional VSI. The capability of suppressing the 2nd order current harmonic from the input dc side is discussed. The basic structures of the proposed inverters and their operation, switch ratings, controller design with supporting mathematical equations, and MATLAB/SIMULINK results are presented. Practical results, based on laboratory prototype circuitry controlled using a Texas Instruments TMSF280335 DSP, are presented to demonstrate the design flexibility and operation of the proposed topologies.

Solar energy is one of the renewable energy that has a large potential in Indonesia. Solar energy can be converted into electrical energy using PV. According to the increasing energy demand in Indonesia and the enactment of the feed-in tariff by the government, it will be easier for the sale and purchase of electricity through the on-grid system. This study discusses the design and implementation of a three-phase grid-connected inverter. This three-phase inverter circuit uses sinusoidal pulse width modulation for input signal (SPWM) is used to input the IR2113 circuit a three-phase inverter driver. SPWM used is also a synchronization method to connect the inverter to the grid. Grid synchronization in this study is equating the phase angle and inverter output frequency to the grid. In this design add DC to DC converter type push-pull converter as a three-phase inverter supply and also as a control to adjust the inverter output voltage to fit the grid. The push-pull converter uses an SG3525 PWM IC generator. The circuit can be adjusted according to the voltage you want to produce. The circuit uses a high-frequency transformer as a step up the voltage. The result of the system design is the PV output voltage is increased by the push-pull converter and then to supply threephase inverter.

This paper work aims at design and implementation of a three-phase Voltage Source Inverter. DC to AC Converter are widely used in the area of renewable energy and in Industrial Drives. Generally, Inverters are used in high power applications for driving Industrial based Motors. Speed Control of Induction Motor is widely done through three-phase Inverter and Inverter convert the DC input from the solar panel to the mains. Hence designing the cost-effective inverter with less harmonics has always been a challenge in the area of Power Converter. This paper explores the design methodology and focuses on designing a simple and cost-effective control circuit for a three-phase Voltage Source Inverter. The switching logic is implemented in a microcontroller (Arduino) and the driver circuit is designed using TLP350 (optocoupler). MATLAB/Simulink and Hardware Design of Three-phase Voltage Source Inverter for 120° mode has been done and it is use to drive 1H.P Three-phase Induction Motor. Designed Inverter was studied and its Harmonic Analysis was done and compare using power analyzer. Both the Hardware and Simulation of three-phase VSI has been explained, compared and is verified.

This article proposes a novel approach to design sliding-mode control (SMC) for an induction motor (IM) in the presence of operational constraints. Different from the traditional techniques in SMC, the proposed method assumes the existence of a constant input disturbance and incorporates it in the switching current control law. Effectively, this leads to integral action through disturbance estimation together with an antiwindup mechanism naturally occurring when the control signal reaches its operational limits. The finite-time convergence of the SMC law is established through a Lyapunov analysis. Experimental evaluations are performed on an industrial-sized IM, where the current dynamics of the motor are controlled using SMC, and a velocity proportional–integral (PI) controller is used for the outer-loop control system. Experimental results reveal that the proposed sliding-mode current control systems provide much improved closed-loop control performance over the traditional SMC system. Further comparative experimental studies with well-designed PI current controllers provide insight into the characteristics of the proposed current control systems.

Sliding mode control (SMC) is recognized as robust controller with a high stability in a wide range of operating conditions, however it suffers from chattering problem. Damping the chattering effect is to smooth the discontinuity of SMC. Nevertheless it also limits the performance of SMC. Moreover in the real implementation of SMC, the sliding surface that is a linear combination of the system state variables and the generated references would drift while the system parameters change or external disturbance exists, which affects the tracking error and THD of system output seriously. In this paper, a fixed switching frequency integral resonant SMC (IRSMC) based on pulse width modulation (PWM) under d-q rotate frame is proposed for three-phase grid-connected inverter with LCL-filter. The chattering problem of SMC is eliminated by adopting Gao's reaching law. In order to obtain an optimal trade-off between the elimination of chattering and the guarantee of performance of SMC, the parameters of SMC are optimized according to the ripple of the system output based on PWM. Moreover, an extra integral term of grid current error is introduced in sliding surface to eliminate the fundamental component of the tracking error. In order to suppress the grid current THD effectively, multiple resonant terms of the grid current error are added to the sliding function. Experimental results on a 30-kVA three-phase grid-connected inverter prototype show the effectiveness of the proposed control strategy.

16 - DC–AC inverters

<span lang="EN-US">In recent years, the demand for energy generated by photovoltaics has increased because of the cheapness of this energy, especially in the Middle East. This study focuses on the design and implementation of a three-phase photovoltaic inverter system for distribution of generator applications. The three-phase inverter used in this study was designed using GWM 100-01X1 as a three-phase full bridge MOSFET package. The MOSFET full bridge of the three-phase inverter is driven using IR2104 gate driver IC, and the Hall sensors of the voltage and current are used to measure the AC and DC voltage and current. The SPWM signal is generated using a PIC24FJ256GB110 as a microcontroller and interfaced to the full bridge package. Simulation and experimental results are presented to validate the three-phase inverter design.</span>

The reliability and security of multicellular converters have become crucial tools for safeguarding electrical power conversion and ensuring the continuity of electrical drives. This concern has always been paramount in numerous industrial applications. Ensuring the reliability, continuity, and robustness of the three-phase multicellular inverter critically depends on accurately diagnosing faults in insulated gate bipolar transistor (IGBT) switches; these failures carry both technical and economic consequences for electrical system conversion. Therefore, detecting and diagnosing faults is crucial to preserving converters against these potential issues. This study aims to investigate the operational behavior of the three-phase multicellular inverter under normal and faulty conditions, more precisely focusing on open-circuit and short-circuit faults in converter switches. To achieve this objective, the paper introduces a fault diagnosis technique based on a sliding mode observer for power switches in the three-phase multicellular inverter. The research is divided into two main sections. The initial segment concentrates on the aspects of sliding mode control, aiming to attain regulated output voltages, output currents, and floating capacitor voltage. This control strategy is essential for maintaining a stable and consistent operation of the inverter. The second segment focuses on fault diagnosis, analyzing the impact of a defective three-phase multicellular inverter on the overall functionality of the electrical system. The performance of the proposed algorithm is assessed and validated through simulations in the MATLAB/Simulink environment.

Power converters (PCs) with their control techniques help regulate voltages of nodes in microgrids with different types of loads such as resistive, inductive, nonlinear, constant power, or critical loads. However, constant power loads (CPLs) affect the stability of the voltage in the output of PCs and are usually difficult to regulate with traditional control techniques. The sliding-mode control (SMC) with the washout filter technique has been recently proposed to address this issue, but studies that consider the phenomenon and parameters present in real systems are required. Therefore, this paper focuses on evaluating the dynamic behavior of an SMC based on a washout filter using three different loads: A constant impedance load (CIL), a nonlinear CPL, and a combination of CIL and CPL. The CIL considered a resistance connected to the circuit, whereas the nonlinear CPL was designed by using a buck converter with zero average dynamics and fixed-point induction control techniques (ZAD-FPIC). The tests consisted of creating some variations in the reference signals to identify the output voltage and the error that the control brings according to the different loads. Besides, this study focuses on representing the dynamic behavior of signals when loads change, considering quantization effects, system discretization, delay effects, and parasitic resistors. Additionally, bifurcation diagrams are created by changing the control parameter k and plotting the regulated voltage and the error produced in the output signals. To illustrate the advantages of the SMC with the washout filter technique, a comparison was made with other techniques such as the proportional–integral–derivative (PID) and conventional SMC by varying the load. The results showed that SMC with the washout filter technique was superior to the PID and the conventional SMC because it stabilizes the signal faster and has a low steady-state error. Additionally, the control system regulates well the output voltage with the three types of load and the system remains stable when changing the parameter k for values greater than 1, with a low error in the steady-state operation.

Two-wheeled balancing robot is a highly nonlinear system that needs a good controller to maintain stability. The linear controller can not anticipate the disturbances such are the uncertainties parameters and hard nonlinearities. Sliding mode control (SMC) is one of the nonlinear control that is robust from disturbances. This paper proposes a way to simplify the designs of control. The movements of balancing robot are controlled with SMC strategy by decoupling the input and designed via Lyapunov analysis. The simulations are presented for evaluating the effectiveness of SMC and compared with the linear controller.

Compared with traditional two-level inverter, three-level inverter has the advantages of low output voltage harmonic distortion, and small switch voltage stress, so it attracts more and more attention in high power applications. In this paper, the bifurcation and chaos in a single-phase three-level inverter are studied. The one-dimensional discrete iterated mapping model under proportional control is established, and the stroboscopic maps in different periods of time are obtained. The bifurcation phenomena in the single-phase three-level inverter are studied when the proportional coefficient k, load resistance R, load inductance L and input voltage E are used as changing parameters. Effects of all these parameters on the system dynamical performances are analyzed on a slow scale using the bifurcation diagram and Lyapunov index spectrum. The bifurcation processes on a fast scale caused by changing values of proportional coefficient and load resistance are visually observed using folded diagram. Finally, the time-domain waveforms with different proportional coefficients are obtained by Matlab/Simulink, which corresponds with the theoretical analysis. The results show that the correct circuit parameters of single-phase three-level inverter are very important for its stable operation.

One of the most significant current studies in DG applications is controlled DC-DC converters. The aim of this paper is to assess the converter performance in the presence of inductive load. It is given an account of and the solution for the drawbacks of using DG resources with inductive load. The purpose of the current study is undertaken to simulate a Phase-shifted Full-Bridge (PSFB) implementing Sliding Mode Control (SMC) with inductive load and evaluate its performance in both tracking a reference current and in system speed. SMC is employed because of its robustness and ability to perform with system uncertainties. Moreover, SMC parameters were optimized using PSO algorithm in order to enhance significantly tracking capability especially in accuracy and speed. A thorough scenario is investigated to show the entire system performance. The results clearly reveal the robustness of the proposed method.

This paper proposes a combined fuzzy adaptive sliding-mode voltage controller (FASVC) for a three-phase UPS inverter. The proposed FASVC encapsulates two control terms: a fuzzy adaptive compensation control term, which solves the problem of parameter uncertainties, and a sliding-mode feedback control term, which stabilizes the error dynamics of the system. To extract precise load current information, the proposed method uses a conventional load current observer instead of current sensors. In addition, the stability of the proposed control scheme is fully guaranteed by using the Lyapunov stability theory. It is shown that the proposed FASVC can attain excellent voltage regulation features such as a fast dynamic response, low total harmonic distortion (THD), and a small steady-state error under sudden load disturbances, nonlinear loads, and unbalanced loads in the existence of the parameter uncertainties. Finally, experimental results are obtained from a prototype 1 kVA three-phase UPS inverter system via a TMS320F28335 DSP. A comparison of these results with those obtained from a conventional sliding-mode controller (SMC) confirms the superior transient and steady-state performances of the proposed control technique.