Z-source Neutral Point Clamped Inverter Research Articles

Shoot-Through Control-Based Space Vector Modulation Approach for a Modified Z-Source NPC Power Inverter

Z-source Neutral Point Clamped (NPC) inverter is a converter topology that combines the benefits of both the impedance network by storing temporary energy released to the load for voltage boosting and NPC inverter by guaranteeing lower Total Harmonic Distortions (THDs) and reducing voltage stresses of switching devices. In this context, this paper deals with a modified three-level Z-source NPC inverter topology with simplified command to generate shoot-through states and reduce switching losses. For this reason, an extra power switch Insulated Gate Bipolar Transistor (IGBT) is added to insert shoot-through, thus eliminating the need for full-shoot-through on any of the three branches of the inverter. On the other hand, a modified Space Vector Modulation (SVM) strategy is proposed. This gives a number of benefits, both in terms of implementation and harmonic performance. Effectiveness of the proposed topology is verified through simulations using Matlab toolbox Simulation and laboratory experiment.

Simulation of Single Phase 3-level Z-source NPC Inverter with PV System

This paper elucidates simulation of single phase 3-level z-source neutral point clamped (NPC) inverter with PV system. single phase NPC inverter employed due to its advantages like less voltage stress, reduced harmonic content, minimsed CMV and voltage stress is low. Z-source network is engaged to boost input voltage getting from the photovoltaic system, which is manoeuvre in shoot through and non-shoot through conditions. This proposed scheme utilized to enhance the output voltage, minimise THD and the leakage current can be avoided with help of split inductor connected with output of inverter system. sinusiodal pulse width modulation (SPWM) used as control technique for the proposed 3-level z-source NPC inverter. The simulation results of this scheme has been verified using matlab/simulink.

Three phase z-source neutral point clamped inverter with multicarrier PWM technique

Purpose The purpose of this paper is to present the three phase seven-level Z-source neutral point clamped (NPC) inverter with multicarrier pulse-width modulation (PWM) technique. Despite numerous topologies and modulation methods, there is a dire need of developing PWM techniques that can be deployed in multilevel inverters. These inverters decrease the total harmonic distortion and it has a good performance for various electrical power system applications. The proposed inverter is investigated for its performance by executing it in shoot through and non-shoot through modes. Design/methodology/approach The purpose is validated through MATLAB/Simulink software platform for implementing the proposed seven-level Z-source NPC inverter outlined with multicarrier based phase disposition technique. The experimental results are verified using SPARTAN 3E FPGA controller with the same control strategy. Findings The efficiency of the proposed inverter is confirmed in terms of increased and faster conversion in the shoot-through mode. By using PDPWM technique the maximum boost gain is achieved with lower modulation index. High control of DC voltage is obtained with only one DC voltage source and one Z network. Originality/value Three phase multilevel inverters are widely used in improving the output voltage quality and reducing the encountered electromagnetic interference in electronic device or circuitry. They are employed in medium and high –power applications to attain increased power ratings while decreasing the switching losses. The performance results shown in this paper will satisfy the above needs of usage in certain applications and less switching losses.

Novel Cascaded Z‐Source Neutral Point Clamped Inverter

Z-source Neutral point clamped (NPC) inverter inherits the advantages of Z-source inverter, which can buck-boost energy and allow the shoot-through states. At the same time, Z-source NPC inverter has high running efficiency and less harmonic content. Hence, it can be widely used in motor drives and fuel cell applications. When increasing the modulation index, one can only get smaller shoot through value in Z-source NPC inverter, therefore the output voltage of the inverter can not be boosted very high. In this paper, a novel cascaded Z-source neutral point clamped inverter is proposed by cascading two Z-source networks in series. An Alternative phase opposition disposition (APOD) carrier-based modulator is applied to control the proposed Z-source inverter. To confirm the operating principle of the new Z-source NPC inverter, a generic APOD carrier-based modulator for the cascaded Z-source NPC Inverter under Matlab/Sinmulink is built. The simulation results show that the boost factor has been increased from 1/(1 − 2D) for the traditional Z source NPC inverter to 1/(1 − 4D) for the proposed cascaded Z-source NPC inverter. A prototype of the cascaded Z-source NPC inverter has been set up. The experimental results verify that the new topology can increase the boost factor and expand the voltage regulation range of the inverter.

Z-SOURCE NEUTRAL POINT CLAMPED INVERTER FED MOTOR DRIVE

Z-source inverter is a recently invented new power conversion concept mainly developed for fuel vehicular applications by advantageously utilizing the shoot through states to boost the DC-bus voltage. The impedance network contains two inductors and three diodes and is connected in between the DC source and inverter bridge. This shoot through state provides the unique buck-boost feature to the DC-link voltage and hence the AC output voltage of the inverter. By varying the boost factor and modulation index, the output AC voltage can be maintained at any value between zero and infinity regardless of DC voltage giving a wide range of voltage. Thus Z-source inverter overcomes the conceptual and theoretical barriers and limitations of the traditional inverters and provides high efficiency single stage structure for buck and boost operation. Previous publications have shown speed control of BLDC motor by controlling the DC link voltage of voltage source inverter using bridgeless buck boost converter. This paper presents the speed control of BLDC motor by controlling the shoot through states of Z-source neutral point clamped inverter using a space vector modulation technique which possess advantage of reduced harmonics with boosted output voltage. The proposed technique is demonstrated in simulation by using MATLAB software.

FPGA Implementation of Z-Source Multilevel Inverter Fed Induction Motor Drives

Multilevel Inverter (MLI) has been recognized as an attractive topology for high voltage DC-AC conversion. Function of a multilevel inverter is to synthesize a desired voltage wave shape from several levels of DC voltages. But the main drawback of MLI is its output voltage amplitude is limited to DC sources voltage summation. To overcome this limitation, a five level neutral point clamped inverter of FPGA based Z-source inverter has been proposed in this paper. In the proposed topology output voltage amplitude can be boosted with Z network shoot-through state control. It employs Z network between the DC source and inverter circuitry to achieve boost operation. The output voltage of proposed inverter can be controlled using modulation index and shoot through state. This paper focuses on multicarrier pulse width modulation (MCPWM) strategy for the three phase five level FPGA based Z-source neutral point clamped inverter have been analyzed. A simulation model of five level FPGA based Z-source neutral point inverter developed using MATLAB/SIMULINK and its performance has also been analyzed.

A Comparison Of Multi Carrier Pwm Techniques Using Z-Source Five Level Diode Point Clamped Inverter

Multilevel Inverter (MLI) has been recognized as an attractive topology for high voltage DC-AC conversion. Function of a multilevel inverter is to synthesize a desired voltage wave shape from several levels of DC voltages. But the main drawback of MLI is its output voltage amplitude is limited to DC sources voltage summation. To overcome this limitation, a Z-source five-level neutral point clamped inverter has been proposed in this work. In the proposed topology output voltage amplitude can be boosted with Z network shoot-through state control. It employs Z network between the DC source and inverter circuitry to achieve boost operation. The output voltage of proposed inverter can be controlled using modulation index and shoot through state. This research work focuses on multicarrier pulse width modulation (MCPWM) strategy for the single phase five level Z-source neutral point clamped inverter. Performance parameters of five-level Z - source neutral point clamped inverter have been analyzed. A simulation model of five level Z-source neutral point clamped inverter developed using MATLAB/SIMULINK 7.13 and its performance has been analyzed.

Space-Vector-Modulated Three-Level Inverters With a Single Z-Source Network

The Z-source inverter is a relatively recent converter topology that exhibits both voltage-buck and voltage-boost capability. The Z-source concept can be applied to all dc-to-ac, ac-to-dc, ac-to-ac, and dc-to-dc power conversion whether two-level or multilevel. However, multilevel converters offer many benefits for higher power applications. Previous publications have shown the control of a Z-source neutral point clamped inverter using the carrier-based modulation technique. This paper presents the control of a Z-source neutral point clamped inverter using the space vector modulation technique. This gives a number of benefits, both in terms of implementation and harmonic performance. The adopted approach enables the operation of the Z-source arrangement to be optimized and implemented digitally without introducing any extra commutations. The proposed techniques are demonstrated both in simulation and through experimental results from a prototype converter.

Analysis and carrier-based modulation of Z-source NPC inverters

Multi-level neutral-point-clamped (NPC) inverters are widely used in high and medium voltage applications. However, these inverters are only buck-type converters. Recently z-source NPC inverters have been proposed as the buck-boost three-level inverter. New inverters use a z-source network as the input stage. This article analyses the features and limitations of two main topologies of z-source NPC inverters (dual z-source network NPC inverter and single z-source network NPC inverter). The low-frequency ripple of the inductor current and the capacitor voltage of the z-source networks in the z-source NPC inverters are surveyed. This article also proposes two novel PWM methods for the z-source NPC inverters, which can be easily implemented experimentally. In the proposed methods, generated switching signals for the conventional NPC inverter are modified for the z-source NPC inverter using a simple logic circuit considering the boost factors and the power sharing ratio. The performance of the proposed simple PWM methods is verified by simulation and experimental results.

Comparative Evaluation of Pulsewidth Modulation Strategies for Z-Source Neutral-Point-Clamped Inverter

Z-source neutral-point-clamped (NPC) inverter has recently been proposed as an alternative three-level buck-boost power conversion solution with an improved output waveform quality. In principle, the designed Z-source inverter functions by selectively "shooting through" its power sources, coupled to the inverter using two unique Z-source impedance networks, to boost the inverter three-level output waveform. Proper modulation of the new inverter would therefore require careful integration of the selective shoot-through process to the basic switching concepts to achieve maximal voltage-boost, minimal harmonic distortion, lower semiconductor stress, and minimal number of device commutations per switching cycle. To date, the theoretical background on Z-source NPC modulation has not been fully established, and it is the theme of this paper to propose a number of enhanced voltage-boost pulsewidth modulation (PWM) strategies for controlling the Z-source NPC inverter. While developing the PWM techniques, attention has been devoted to carefully derive them from a common generic basis for improved portability, easier implementation, and most importantly, assisting readers in understanding all concepts that have been presented. The presented strategies are also comparatively evaluated to identify their individual advantages and disadvantages, which are subsequently summarized in a comprehensive reference table. Last, simulation and experimental results are included for validating the performances and practicalities of the presented modulation schemes

Pulsewidth-Modulated $Z$-Source Neutral-Point-Clamped Inverter

This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology for designing a three-level inverter with both voltage-buck and voltage-boost capabilities. The designed Z-source NPC inverter uses two unique X-shaped inductance-capacitance (LC) impedance networks that are connected between two isolated dc input power sources and its inverter circuitry for boosting its AC output voltage. Through the design of an appropriate pulsewidth-modulation (PWM) algorithm, the two impedance networks can be short-circuited sequentially (without shooting through the inverter full DC link) for implementing the ldquonearest-three-vectorrdquo modulation principle with minimized harmonic distortion and device commutations per half carrier cycle while performing voltage boosting. With only a slight modification to the inverter PWM algorithm and by short-circuiting the two impedance networks simultaneously, the designed NPC inverter, with no requirement for deadtime delay, can also be operated with a completely eliminated common-mode voltage. Implementation wise, a detailed vectorial analysis interestingly shows that the same generic set of carrier-based modulation expressions can be used for controlling the -source two-level inverter and NPC inverter with and without reduced common-mode switching. All findings presented in this paper have been confirmed in simulation and experimentally using an implemented laboratory prototype.