Traditional Voltage Source Inverter Research Articles

Real-time performance analysis of modified z-source inverter-fed induction motor drives using xilinx system generator

This paper contributes to the performance evaluation of modified z-source inverter (ZSI) for medium voltage induction motor drives using the Xilinx System Generator. Controlling the shoot-through duty ratio of the modified ZSI, can boost the inverter output voltage during input voltage sags and maintain the desired output voltage level at the motor terminal. The proposed drive system eliminates voltage sag problem and surpasses the demerits of the traditional voltage source inverter drives. The proposed system is executed in FPGA based real-time digital simulator at fixed step solver with fixed-time step and constant switching frequency. Real-time simulation results show the performance of 225 KW, 3.3 kV induction motor for modified ZSI based adjustable speed drives during steady and dynamic states.

Model Predictive Control of Quasi-Z-Source Four-Leg Inverter

This paper presents a model predictive control (MPC) scheme for quasi-Z-source (qZS) three-phase four-leg inverter. In order to cope with the drawbacks of traditional voltage source inverters (VSIs), a qZS three-phase four-leg inverter topology is proposed. This topology features a wide range of voltage gain which is suitable for applications in renewable energy-based power systems, where the output of the renewable energy sources varies widely with operating conditions such as wind speed, temperature, and solar irradiation. To improve the capability of the controller, an MPC scheme is used which implements a discrete-time model of the system. The controller handles each phase current independently, which adds flexibility to the system. Simulation and experimental studies verify the performances of the proposed control strategy under balanced and unbalanced load conditions as well as single-phase open-circuit fault condition.

Analysis and Design of Solar Photo voltaic Grid Connected Inverter

This paper presents common mode voltage analysis of single phase grid connected photovoltaic inverter. Many researchers proposed different grid tie inverters for applications like domestic powering, street lighting, water pumping, cooling and heating applications, however traditional grid tie PV inverter uses either a line frequency or a high frequency transformer between the inverter and grid but losses will increase in the network leading to reduced efficiency of the system. In order to increase the efficiency, with reduced size and cost of the system, the effective solution is to remove the isolation transformer. But common mode (CM) ground leakage current due to parasitic capacitance between the PV panels and the ground making the system unreliable. The common mode current reduces the efficiency of power conversion stage, affects the quality of grid current, deteriorate the electric magnetic compatibility and give rise to the safety threats. In order to eliminate the common mode leakage current in Transformerless PV systm two control algorithms of multi-carrier pwm are implemented and compared for performance analysis.The shoot-through issue that is encountered by traditional voltage source inverter is analyzed for enhanced system reliability. These control algorithms are compared for common mode voltage and THD comparisons. The proposed system is designed using MATLAB/SIMULINK software for analysis.

High-efficient three-phase on-line UPS by using T-source inverter with third harmonic injected maximum constant boost PWM control

This paper presents the analysis of three-phase on-line uninterruptible power supply (UPS) by employing T-source inverter (TSI) with third harmonic injected maximum constant boost PWM control and the results are compared with traditional UPS. Traditional UPS consists of step-up transformer or DC–DC booster along with voltage source inverter which decreases the efficiency and increases energy conversion cost. The proposed three-phase UPS using TSI has high-voltage boost capability through shoot-through zero state which is not present in traditional voltage source inverter (VSI) and current source inverter. This proposed UPS with TSI increases the efficiency with fewer components, reduces the harmonics, increases the voltage gain, and reduces the voltage stress. The performance of three-phase on-line UPS based on TSI is analyzed and evaluated in MATLAB/SIMULINK software and the results are compared with Z-source inverter-fed UPS and VSI-fed UPS. Experimental results are presented for the validation of the simulation and theoretical analysis.

Design and implementation of maximum constant boost switched inductor z-source inverter for three-phase on-line uninterrupted power supply

Purpose – The purpose of this paper is to present the Switched Inductor Z-Source Inverter (SLZSI) topology for three-phase on-line uninterruptible power supply (UPS) by employing third harmonic injected maximum constant boost pulse width modulation (PWM) control. Conventional UPS consists of step-up transformer or boost chopper along with voltage source inverter (VSI) which reduces the efficiency and increases energy conversion cost. The proposed three-phase UPS by using SLZSI has the voltage boost capability through shoot through zero state which is not available in traditional VSI and current source inverter. Design/methodology/approach – Performance of three-phase on-line UPS based on ZLZSI by using third harmonic injected maximum constant boost PWM control is analyzed and evaluated in MATLAB/Simulink software and the results are compared with Z-source inverter (ZSI) fed UPS. Experimental results are presented for the validation of the simulation and theoretical analysis. Findings – The output voltages, currents, THD values, voltage stress and efficiencies for different loading condition are determined and compared with the theoretical values and UPS with ZSI. The experimental results validate the theoretical and simulation results. Originality/value – Compared with the traditional ZSI, the SLZSI provides high-voltage boost inversion ability with a very short shoot through zero state. This proposed UPS by using SLZSI increases the efficiency with less number of components, reduces the harmonics, increases the voltage gain and reduces the voltage stress.

Losses in Medium-Voltage Megawatt-Rated Direct AC/AC Power Electronics Converters

Direct ac/ac topologies for ac-to-ac power conversion benefit from the absence of dc-link capacitors, and therefore, are highly reliable and have low cost as compared to the traditional voltage-source inverter (VSI)-based topologies. This paper deals with one of the more important tradeoffs considered in designing highly efficient converters: Losses. It is shown in this paper that the direct ac/ac converters have an inherently higher efficiency than their VSI-based back-to-back counterparts due to a dramatic reduction in switching losses (nearly 60%). Further, this paper compares the performance of three different device types (SiC MOSFETs, hybrid Si IGBT/SiC diode, and Si IGBTs) using wide-range device characterization that help to create detailed loss models. It is conjectured that traditional datasheets lack the level of detail needed for computing losses in direct ac/ac converters, and the availability of a multivalue voltage, current, and temperature-based loss profile is advocated. Using the obtained loss models, a comparison is drawn between the considered devices through simulations when operated in a 13-kV/1-MW direct ac/ac power flow controller, the controllable network transformer (CNT). The same loss-models are also used to compute losses in an experimental prototype of a 720-V, 10-kVA CNT and the results are compared with direct efficiency measurements. A similar computation is carried out for another experimental prototype at a 6.7-kV, 400-kVA, three-level, paralleled CNT. These experimental tests are used to confirm the validity of the analytical results presented in this paper.

T Source Inverter Based Shunt Active Filter with LCL Passive Filter for the 415V 50 Hz Distribution systems

The inverter topology is being used as an active filter to reduce the harmonics in the power system. The traditional voltage source or current source inverters are having the disadvantages of limited output voltage range hence it may not be able to supply enough compensating currents during heavy switching surges, Vulnerable to EMI noise and the devices gets damaged in either open or short circuit conditions and the main switching device of VSI and CSI are not interchangeable. The active filters are the type of DC-AC system with wide range of voltage regulation and integration of energy storages is often required. This cannot be achieved with conventional inverters and hence the impedance source inverters have been suggested. The T source inverters are basically impedance source inverters which can be used as an active filter in the power system. The MATLAB simulation is done and the results are discussed in this paper for both the types. The proposed dampening system is fully characterized by LCL based passive filters and T source inverter based shunt active filter. The disturbances in the supply voltage and load current due to the non linear loads are observed in the simulation. The same is studied after connecting the designed hybrid shunt active filter in the distribution system. The simulation results obtained from the proposed method proves that it gives comparatively better THD value.

Fuel Cell Fed Induction Motor Speed Control Through Z Source Inverter

This paper presents the Z- source inverter feeding to an Induction motor (IM). This Z-source inverter is also be used to boost up the available low voltage DC supply from the fuel cell. This paper has been proposed the speed control of fuel cell fed induction motor through z source inverter. The speed control of an induction motor is a highly efficient this can be used in numerous adjustable speed applications. To achieve transient performance, the peak DC link voltage is employed, which improves rejection of disturbance. SVPWM is used in switching algorithm. The closed loop SVPWM control technique of an induction motor is shown. This technique is widely used in industry. The performance of the proposed speed control method is verified through MATLAB/simulation. The simulation results of proposed scheme present good dynamic and steady state performance over the traditional voltage source inverter fed induction motor drive.

Healthcare Solution Using Machine to Machine Communication

This paper provides a prototype which uses machine to machine communication to provide healthcare solution. ECG and PPG is an important tool to interpret a wide range of heart conditions. Early warning and patient awareness are critical in preventing permanent heart damage and saving much of the heart muscles. These critical conditions motivated us to develop a prototype that provides a long term ECG and PPG monitoring. This prototype consists of ECG and PPG sensors at the patient’s side, that monitors the ECG and PPG and record the signals, this readings are then transmitted with the help of internet to the hospital server. These readings can be accessed in real time by the doctor’s smart phone with the help of android app. Our approach is to provide healthcare solution which can process large amount of biomedical signals through the network that is a combination of internet and sensors. performance over the traditional voltage source inverter fed induction motor drive.

A comprehensive study of space vector pulse‐width modulation technique for three‐phase Z‐source inverters

SummaryThe space vector pulse width modulation (SVPWM) technique has received much attention for three‐phase Z‐source inverters (ZSIs). The differences and connections between the SVPWM technique for ZSIs and for traditional voltage source inverters have been discussed as well. By selecting different null state and shoot‐through state, three switching patterns with different switching numbers have been studied, and the harmonic spectrums of these three patterns are demonstrated. In this paper, the solutions of maximum boost control and constant boost control methods using SVPWM techniques with less switching actions have been proposed and compared with the carrier‐based strategies. Selected experimental results have been provided to validate the theoretical analysis. This work will be beneficial for understanding the SVPWM concept and modulation techniques of the three‐phase ZSIs. Copyright © 2015 John Wiley & Sons, Ltd.

Phase‐shift control and harmonics elimination for H‐bridge Z‐source inverter

Phase-shift control is a common approach to voltage control of traditional H-bridge inverters, but this method has not been used to voltage control of H-bridge Z-source inverter (ZSI) so far. This study proposes a new phase-shift control method for H-bridge ZSI, which its main difference with phase-shift control of traditional H-bridge inverters is existence of four shoot-through states (short circuit of the H-bridge) in each switching cycle. One of the advantages of the proposed method is simultaneous elimination of several harmonics by choosing the appropriate switching angles. Moreover, by using this phase-shift control method, the amplitude of low-order harmonics for many values of switching angles is less than the amplitude of low-order harmonics in traditional H-bridge voltage source inverter (VSI). Total harmonic distortion and distortion factor, as two important indexes for quantifying the merits of the proposed method, are calculated and compared with their values in traditional H-bridge VSI. A detailed description of suggested method and comparison with the traditional method are presented in this study. Simulation and experimental results are also given to demonstrate the new features of the proposed method.

Z-Source Inverter Based Motor Drives for Industrial Medium Voltage Application

This paper presents an application of z-source inverter for industrial medium voltage drives. Z-source inverter based drive has advantages like boosting the output voltage during voltage sag, reducing harmonic distortion and improving the input power factor. Adjustable speed drives (ASD’s) are interrupted due to voltage sag, reducing the manufacturing and financial losses. The medium voltage ac drives are limited to low value of switching frequency because of dynamic losses of the power devices. Using the proposed technique, it can remove those limitations. In this paper, the performance of traditional voltage source inverter is compared to that of z-source inverter for medium voltage drives under different operating conditions. Simulation results show the dynamic performance of z-source inverter based 225KW, 3.3KV induction motor drives during input supply fluctuation. The proposed closed loop control method provides nearly zero steady state speed error at any operating frequency.

Symmetric and Asymmetric Design and Implementation of New Cascaded Multilevel Inverter Topology

Nowadays, use of multilevel inverters in high-power applications clearly can be seen. High quality and lower distortion of the output voltage and low blocking voltage of semiconductor switches are being presented as the major privileges of the multilevel inverter compared to the traditional voltage source inverter. In this paper, a new topology of multilevel inverter is proposed as fundamental block. The proposed topology is generalized using series connection of the fundamental blocks. The proposed multilevel inverter has been analyzed in both symmetric and asymmetric operation modes. A great perfection in voltage levels number with minimum switching devices has been obtained in both symmetric and asymmetric modes. Thereafter, a detailed study of losses and peak inverse voltage (PIV) of the proposed multilevel inverter is given. Also, in continuation, a comparison between the proposed topology and the traditional one and a recently developed topology is carried out. Finally, a computer simulation using MATLAB/Simulink is presented and a laboratory prototype implementation verifies the results.

Z-Source\/Quasi-Z-Source Inverters: Derived Networks, Modulations, Controls, and Emerging Applications to Photovoltaic Conversion

The current and emerging investigations on Z-source/quasi-Z-source inverters (ZSIs/qZSIs) are presented. The ZSI/qZSI fulfills buck/boost capability in single-stage topology and overcomes the limits of traditional voltage source inverters (VSIs). Hence, high reliablity, high efficiency, and low cost can be achieved. The recently derived impedance networks with improved voltage gain are discussed. The classic and newly proposed modulations and feedback controls for ZSIs/qZSIs are compared. Finally, the emerging applications and trends of ZSIs/qZSIs to photovoltaic (PV) power generation are discussed. This study offers a comprehensive and systematic reference for the future development of the high-performance ZSI/qZSI.

Impedance network design and its critical value prediction of tapped‐inductor single‐stage boost inverter

This study proposes a high inversion gain single-stage boost inverter, which introduces a tapped inductor impedance network, including one tapped inductor and two diodes, to add to the front end of traditional voltage-source inverter, called tapped-inductor single-stage boost inverter (TISSBI). The TISSBI has the merits of high inversion gain, common ground of input and dc-bus, continuous input current and reduced capacitor voltage stress. This study also presents all the possible steady states of the TISSBI proposed. It is shown that, in addition to the desired three steady states, an operating cycle can contain another four abnormal states that do not contribute to the power conversion process. These four states can be avoided by selecting suitable value of capacitance and inductance. By using the equations derived in the steady-state analysis, this study presents guidelines to design the impedance network accurately. Experimental results are provided to verify the effectiveness of the proposed circuit, the design method of impedance network and demonstrate the appearance of the four states when the capacitors and inductors are smaller than their critical values.

Z Source Inverter Using Renewable Energy System

This paper presents a high performance, low cost inverter for Photo voltaic systems based on Z-source concept. Traditional Voltage-source inverter and Current Source Inverter has improved to the new Z-Source Inverter. This impedance source inverter can provide a single stage power conversion concept where as the traditional inverter requires two stage power conversion. A new low cost solar cell powered Z-source inverter system is simulated and the results are compared with the traditional Voltage Source Inverter system. Performance analysis confirms that Z source inverter system is more appropriate for photo voltaic applications. The Z-source concept can be applied to all dc-to-ac, ac-to-dc, ac-to-ac, and dc-to-dc power conversion.

An Off-line Battery Charger based on Buck-boost Power Factor Correction Converter for Plug-in Electric Vehicles

This paper presents an off-line battery charger based on the buck-boost power factor correction (PFC) converter for plug-in electric vehicles (EV). The integrated battery charger is obtained from the traditional three-phase voltage source inverter (VSI) for EV, which operates as buck-boost converter with power factor correction ability. The PFC controller is regulates the battery voltage and controls the supply current of the converter to achieve unity power factor which is very simple and gives good performance. The proposed buck-boost PFC converter is operating in buck mode and boost mode, which is alternatively carried out according to the relationship between the rectified input voltage and battery voltage. The practicality and performance of the battery charger of the proposed converter topology has been verified via simulation.

Different Types of PWM Techniques analysis for Z-Source Inverter

This paper presents a recent popular power inverter which is impedance source or Z-source inverter (ZSI) and the comparison and analysis of two conventional PWM techniques of Z-source inverter. Due to the impedance network it couples inverter main circuit to the power source thus providing special features that can overcome the limitations of traditional voltage source inverter (VSI) and current source inverter(CSI).In this paper we discussed and analyzed about the different conventional PWM techniques like Simple Boost Control, Maximum Boost Control, Maximum Boost Control with third harmonic injection, Maximum Boost Control with triplen injection where it is observed that the Maximum Boost Control with triplen injection is much better than other techniques in respect of load current ripple, inductor current ripple and capacitor voltage ripple for different modulation index and same switching frequency.

Analysis and PWM Control of Switched Boost Inverter

The Z-source inverter (ZSI) employs an <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> impedance network between the main inverter bridge and the power source. The unique feature of the ZSI is that it can operate either in buck or boost mode with a wide range of obtainable output voltages from a given input voltage. This topology also exhibits better electromagnetic-interference noise immunity when compared to a traditional voltage-source inverter (VSI). However, the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> impedance network of ZSI significantly increases the size and cost of the power converter and can make it unsuitable for low-power applications. This paper proposes a novel topology called switched boost inverter (SBI) which exhibits similar advantages of ZSI with lower number of passive components and more active components compared to ZSI. The steady-state and small-signal analyses of SBI, along with its pulsewidth modulation (PWM) control strategies, have been discussed in this paper. This paper also presents a comparison of SBI and ZSI with the same input and output parameters. The theoretical analysis given in this paper has been validated using a laboratory prototype of SBI, and the experimental results are presented for verification. The experimental harmonic spectrum of the inverter's output voltage with the proposed PWM technique is also plotted and compared with that of a traditional VSI. All the experimental results show good correlation between theory and experiments.

IMPLEMENTATION OF IMPEDANCE SOURCE INVERTER SYSTEM FOR PHOTOVOLTAIC APPLICATIONS

This paper presents a high performance, low cost inverter for photovoltaic systems based on Impedance-source concept. Traditional Voltage-source inverter and Current-source inverter has improved to the new Z-source inverter, with a unique X-shaped network in it. This Impedance-source inverter can provide a single stage power conversion concept where as the traditional inverter requires two stage power conversion for renewable energy applications. A new low cost solar cell powered Z-source inverter system is simulated and the results are compared with the traditional Voltage-source inverter system. Performance analysis, simulation and comparison have been confirmed that the Z-source inverter system is more appropriate for photovoltaic application than their counterparts. Hardware implementation is done to validate the proposed system.