Voltage Source Inverter Switching Research Articles

Analysis and Measurement of Non-Intrinsic Differential-Mode Noise in a SiC Inverter Fed Drive and Its Attenuation Using a Passive Sinusoidal Output EMI Filter

The analysis, measurement, and attenuation of non-intrinsic differential-mode (NDM) and common-mode (CM) noise in an induction motor (IM) drive are discussed in this paper. In a voltage source inverter (VSI) fed drive, the NDM noise is caused by the excitation of the CM capacitance paths by the line to ground voltage. A measurement method at the input side of IM is proposed to separate intrinsic differential-mode (IDM), NDM, and CM noise from the total line current. It is substantiated that the NDM noise constitutes a significant portion of the measured DM noise. Hence, a passive sinusoidal output electromagnetic interference (EMI) filter (PSOEF) is presented to attenuate the NDM and CM noise. PSOEF is designed using line inductor & capacitor with the same resonance frequency to attenuate the NDM and CM noise. PSOEF has an advantage of reduced size and number of CM components as compared to conventional sinusoidal output EMI filter (CSOEF). The designed PSOEF is presented with space vector pulse width modulation (PWM) and CM voltage reduction PWM to analyze the attenuation performance, circulating current, and filter loss. The proposed measurement method and the design of PSOEF are experimentally validated on a SiC VSI switching at 200 kHz.

The Improved Unified Power Quality Conditioner with the Modular Multilevel Converter for Power Quality Improvement

Nowadays, researchers focus on the modular multilevel converter (MMC), due to its modularity structure, effective sharing of voltages among the submodule switches, and betterment in the quality of the voltage and current waveforms. First, the conventional unified power quality conditioner is developed with two level voltage source converters connected back-to-back, which are proposed to mitigate both the voltage and current related power quality problems. Later, to improve the performances (voltage sag, swell, current harmonics, etc.) of the conventional method, multilevel inverters are used. In this paper, a modified unified power quality conditioner based on a modular multilevel converter is implemented to mitigate the voltage and current related power quality issues. The design of the MMC is very simple with a modular structure, and it also improves the performance of the system compared to the conventional methods. In this proposed topology, the voltage related compensation is implemented with a seven-level MMC, and the current compensation is achieved with a reduced four switch voltage source inverter. The developed system is simulated in the MATLAB platform, and results are validated by hardware implementation with a FPGA controller. It is observed that the developed system has less % of total harmonic distortion and reduction in voltage sag as per the prescribed IEEE 519–2014 standards and practices.

SAPF for Power Quality Improvement Based on PSODE Optimization Algorithm

PQ phenomenon has gain an overwhelming attention in recent years for extensive use of complicated industrial processes. In the modern world, the usage of intelligent algorithms to enhance power quality is increasing gradually as the present day utility system as a linear model is unsatisfactory and ineffective. This paper emphasis on comparative analysis of PSODE with traditional PSO and DE for the harmonic reduction in source current with optimal tuning of proportional integral (PI) controller gain values. The SAPF is dominant among the power quality conditioners used to limit the current variations that are induced in the utility system because of nonlinear loads. The reference current generation is based on PQ theory. The instantaneous switching of voltage source inverter (VSI) is taken care by hysteresis band current controller (HBCC). The pro-effective simulations are implemented in the MATLAB/SIMULINK environment, which even supports the efficacy of the present day power system.

BLDC Motor Drive Based on Bridgeless Landsman PFC Converter With Single Sensor and Reduced Stress on Power Devices

The Landsman converter based on a power factor correction (PFC) in bridgeless (BL) configuration feeding a brushless dc motor (BLDCM) drive is proposed for low-power household appliances. The conduction losses associated with diodes are reduced by BL configuration and switching losses of solid-state switches of voltage source inverter are reduced by the use of low frequency switching signals in electronic commutation for the BLDCM. The front-end BL PFC based Landsman converter operating in the discontinuous inductor current mode is used for controlling the dc link voltage, and PFC is attained naturally with reduced conduction losses and switch stress. A single voltage sensor is used for controlling the dc bus voltage. A prototype is developed to study performance of the system for wide range speed control and power quality improvement. The experimental performance of BLDCM is presented for its functions at varying voltages of ac mains (90–265 V) to adhere to the limits defined by IEC61000-3-2 standard.

Digital predictive current control of multi‐level four‐leg voltage‐source inverter under balanced and unbalanced load conditions

This study investigates the experimental validation of finite control set–predictive current control (FCS-PCC) of a multi-level four-leg voltage-source inverter (VSI) operating under balanced and unbalanced conditions. The proposed topology is a combination of conventional four-leg VSI with an additional four switches circuit serving as dc voltage synthesiser. Unification of both circuits can supply energy to unbalanced three-phase loads by providing the path for a zero-sequence load while maintaining appropriate load voltage to the system. The proposed control strategy takes advantage of the discrete nature of the power converter system to predict the future behaviour of the output current. FCS-PCC is based on an optimal approach that selects the most accurate switching signals among 48 valid switching states by computing cost function and applying switching state that minimises the tracking error to the next sampling time. The proposed control has been experimentally verified to assert the robustness of the control. The prominent outcomes of the experiments confirm the ability of independent load current reference tracking with harmonics distortion lower than the conventional eight switches VSI.

A general model for 6 switch voltage source inverter

While simulating electrical systems it is often important to determine all the current and voltage signals in a 6 switch voltage source inverter. Typically, the inverter model structure depends on the application it has to supply. As a consequence only a limited number of switching state combinations are modeled. Simulation software often offers black box blocks able to handle all switching states. However, such methods often involve iterative solvers because the voltage and current signals affect each other which results in a high computational cost. In this paper, a general model, which considers all possible switching states is introduced. Using this model it is possible to determine all current and voltage signals using only one single matrix inverse regardless of the application and with a reasonable computational effort. Both balanced and unbalanced time dependent load behavior can be considered. The model is validated with measurements on a test setup with an unbalanced load and a brushless DC motor.

Mathematical Derivation of Switching Angles of Multilevel Voltage Source Inverter based on Alternative Phase Opposition Disposition (APOD)

Modular structured multilevel inverter is very useful for electrical application especially in high voltage and high power applications. The main function of this multilevel inverter is to produce multilevel AC output voltage from several separate DC sources. This project is to derive a newmathematical formulation of multilevel voltage source inverter switching instants. The proposed method for this project is based on the sinusoidal natural sampling PWM (SPWM) by comparing several modified modulation signal with a triangular carrier signal. This resulting intersection points between this modulation and carrier signal become the switching instants of the PWM pulses. Derivation also based on Alternative Phase opposition disposition (APOD). A cascaded multilevel inverter is selected as a topology for this project due to major advantages compare with other topology. The derived formula is analyzed by using MATLAB simulation software. It is found that the results that use the derived formula are almost identical to simulation result.

Brushless DC motor drive with power factor regulation using Landsman converter

This study presents a novel configuration of power factor regulation (PFR)-based Landsman converter feeding a brushless DC motor (BLDCM) drive for low-power (400 W) white goods applications. The speed control of the drive is achieved through adjusting the DC bus voltage of voltage source inverter (VSI) feeding to a BLDCM. Moreover, low-frequency switching signals are used for electronic commutation of BLDCM, which reduces the switching power losses of six solid-state switches of VSI. This Landsman converter-based front-end power factor corrector operating in discontinuous inductor current mode is used to control DC bus voltage and PFR is achieved inherently. The DC bus voltage of the drive is controlled by using a single DC voltage sensor. For evaluating the performance of proposed drive, a prototype is developed in the laboratory. The performance of the BLDCM is also analysed for its operation at varying AC mains voltage (90–265 V). Experiential results for power quality indices are found within the limits of power quality standard IEC 61000-3-2.

Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

A Soft Switching Control Strategy Based on Interleaved Boost Converter for BLDC Motor Drive

In this paper, Zero-Voltage-Transition (ZVT) two-cell interleaved boost Power Factor Correction (PFC) converter for voltage source Inverter (VSI) fed permanent magnet brushless DC motor (PMBLDCM) drive has been proposed Scheme reduce the torque ripple of BLDC motor drive and also reduce the switching losses of VSI for Which an auxiliary circuit is designed and added to the interleaved boost converter. For achieving soft switching, only one switch is used in auxiliary circuit which reduces the torque ripple and switching losses. In this proposed control strategy, the DC link voltage is controlled with interleaved boost converter which is proportional to the desired speed of the BLDC motor. In this paper, six switch and four switch VSI is also implemented with interleaved boost converter topology. A comparison is made between the six switch and Four Switch VSI fed PMBLDC Motor drive and Torque Analysis as been done. To validate the proposed work, results are presented. The results showed that proposed converter control strategy operating under soft switching mode improves the efficiency of the drive system with PFC feature in wide range of the speed control.

Mathematical Formulation of Multilevel Voltage Source Inverter Switching Instants

Modular structured multilevel inverter is very useful for electrical application especially in high power and high voltage applications. The main function of this multilevel inverter is to produce multilevel AC output voltage from several separate DC sources. This project is to derive a new mathematical formulation of multilevel voltage source inverter switching instants. The proposed method for this project is based on the sinusoidal natural sampling PWM (SPWM) by comparing several modified modulation signal with a triangular carrier signal. This resulting intersection points between this modulation and carrier signal become the switching instants of the PWM pulses. Derivation also based on Phase opposition disposition (POD). A cascaded multilevel inverter is selected as a topology for this project due to major advantages compare with other topology. The derived formula is analyzed by using MATLAB simulation software. It is found that the results that use the derived formula are almost identical to simulation result.

Improved three‐phase, five‐level pulse‐width modulation switched voltage source inverter

This study presents an improved three-phase, five-level pulse-width modulation (PWM) switched voltage source inverter. The single-carrier, multilevel PWM scheme is employed to generate the gating signals for the power switches. Operational principles with switching functions are given. By controlling the amplitude modulation index, three- and five-level output phase voltage waveforms can be achieved. For modulation indices of 0.45, and 0.9, the proposed inverter topology was subjected to an R–L load and the respective number of output voltage level were synthesised. For a step change in the modulation index, the response of the proposed multilevel inverter circuit topology is demonstrated. Fast Fourier transform analyses of the output line voltage waveforms, at the indicated depth of modulation, were carried out and the corresponding total harmonic distortion values were obtained. Comparison of the proposed inverter configuration and the classical 3-ϕ topologies is given based on the power circuit component count. Moreover, analysis of the conduction power losses in the power semiconductor switches of the proposed inverter topology is given. To verify the performance of the proposed inverter architecture, simulations and experiments are carried out on a 3.46 kW rated prototype of the proposed inverter for an R–L load; and adequate results are presented.

PFC Cuk Converter-Fed BLDC Motor Drive

This paper deals with a power factor correction (PFC)-based Cuk converter-fed brushless dc motor (BLDC) drive as a cost-effective solution for low-power applications. The speed of the BLDC motor is controlled by varying the dc-bus voltage of a voltage source inverter (VSI) which uses a low frequency switching of VSI (electronic commutation of the BLDC motor) for low switching losses. A diode bridge rectifier followed by a Cuk converter working in a discontinuous conduction mode (DCM) is used for control of dc-link voltage with unity power factor at ac mains. Performance of the PFC Cuk converter is evaluated under four different operating conditions of discontinuous and continuous conduction modes (CCM) and a comparison is made to select a best suited mode of operation. The performance of the proposed system is simulated in a MATLAB/Simulink environment and a hardware prototype of the proposed drive is developed to validate its performance over a wide range of speed with unity power factor at ac mains.

English

The tradition of non-linear loads in Electrical power system has sparked the research in power quality (PQ) concern like voltage flicker, voltage sag and swell, harmonics, etc., Among all the other concerns, one of the major significant PQ problem is Harmonics. The inception of Nonlinear Load into the power system will have the effect of harmonics. These nonlinear loads appear to be prime sources of harmonic distortion in a power distribution system. Harmonics have a number of undesirable effects like Voltage flicker, voltage sag and swell, harmonics etc., on the distribution system. These harmonics are to be mitigated for Power Quality Enhancement. The STATCOM is one of the FACTS Devices which can be used to mitigate the harmonics. The necessity of using intelligent tools in power quality analysis is increasing day by day to enhance power quality in the utility. This paper deals with analysis and comparison of optimized PI based Differential Evolution (DE) technique and controlled fuzzy-PI controller with conventional PI controller used in STATCOM for harmonic reduction in the source current. SRF theory is used to generate the reference compensating currents. Hysteresis Band Current Controller (HBCC) is used to control the switching of Voltage Source Inverter.

Balancing Switching Losses in Three-phase, Five-level Pulse-width Modulation Switched Voltage Source Inverter Using Hybrid Modulation Techniques

This article proposes a new switching strategy for a three-phase, five-level switched voltage source inverter. The single-carrier, multi-level pulse-width modulation (PWM) scheme is employed to generate gating signals for the power switches. The proposed modulation scheme is hybridized to enable the output voltage of the inverter configuration, inheriting the features of switching-loss reduction from fundamental PWM and good harmonic performance from multiple sinusoidal PWM. A sequential switching scheme is embedded with the already-employed hybrid modulation to overcome unequal switching losses and, therefore, differential heating among the power devices. Operational principles with switching functions are given. For an R-L load, Fast Fourier Transform (FFT) analyses of the output voltage waveforms were carried out, and the corresponding total harmonic distortion value of 26.09% was obtained. To verify the performance of the proposed modulation scheme, simulations and experiments are conducted on a 1.2-kW rated prototype of the inverter; adequate results are presented.

Cascaded three‐phase pulse‐width modulated switched voltage source inverter

A cascaded three-phase pulse-width modulated (PWM) switched voltage source inverter topology is proposed. Each of the two cascaded units in a phase-leg is an H-bridge, whose switch legs are separated by a switched capacitor and a diode. Three upper H-bridges in this inverter configuration have separate dc inputs; whereas the lower three H-bridges share a common dc input. A single-carrier, multilevel PWM scheme is employed to generate the gating signals for the power switches. The implemented modulation scheme is hybridised to enable the output voltage of the proposed inverter configuration inherit the features of switching-loss reduction from fundamental PWM, and good harmonic performance from multiple sinusoidal PWM. A sequential switching scheme is embedded with the already employed hybrid modulation in order to overcome unequal switching losses. Furthermore, a simple base PWM circulation scheme is also introduced to get a resultant sequential switching hybrid PWM circulation that balances power dissipation among the two cascaded power modules. The proposed inverter configuration was subjected to an R–L load. Fast Fourier transform analyses of the output voltage waveforms gave total harmonic distortion value of 12.64%. Simulations and experiments are carried out on a 4.89 kW rated prototype of the proposed inverter.

The modified space vector PWM for three-phase voltage source inverter with AC decoupling circuit

This paper proposes the modified space vector pulse width modulation (SVPWM) control algorithm for the three-phase voltage source inverter (VSI), which consists of traditional six switches VSI and three bidirectional switches for creating the ac decoupling circuit. This topology has some advantages such as the ability to reduce the leakage ground current from PV panel and therefore improve the efficiency of photovoltaic (PV) energy conversion based on the principle of decoupling when the zero space vectors occur. Likewise, no current flows through six traditional switches in zero space vectors, thus they operate at lower average temperature. In this case, the conduction losses are reduced. For avoiding shoot-through states between six traditional switches and three bidirectional switches, a delay time has been added to switching time and managed carefully to guarantee THD of output voltage. Operating of the inverter with the modified SVPWM method is simulated by using Matlab/Simulink software and implemented in the experimental prototype by using FPGA Virtex 5 (Xilinx).

Pulse width modulation schemes enabling single DC power source driven dual two‐level voltage source inverter with single voltage source inverter switching

Three-level voltage space phasor can be obtained using a dual two-level voltage source inverter (VSI). Two zero sequence voltage elimination pulse width modulation (PWM) switching variants are proposed in this paper for complete elimination of zero sequence voltage (ZSV) in the dual-VSI scheme. Both the PWM variants are designed in such a way that only one inverter is switched at any instant of time; to ensure that switching power losses in the dual-VSI is limited to one inverter only at any instant of time. Analytical expressions for the dwell times of the dual-VSI are developed and presented that successfully forces the ZSV in the dual-VSI to zero; at all instants of time. As a result, both the PWMs facilitate the dual-VSI to be driven from a single DC power source only. The implementation of the proposed PWM algorithms is greatly simplified and involves just the use of instantaneous magnitudes of the reference space vector. The implementation of PWMs totally avoids the time consuming task of sector identification and do not use look up tables. The PWMs proposed in this paper are first analysed, simulated using MATLAB/SIMULINK and then verified experimentally to validate the proposed PWMs.

Power quality improvements in power factor correction Luo converter fed brushless direct current motor drive

Summary This paper presents a power factor correction (PFC) Luo converter based voltage source inverter (VSI) fed brushless direct current (BLDC) motor drive using a single voltage sensor. A single-phase diode bridge rectifier followed by a Luo converter operating in discontinuous inductor current mode (DICM) is used for the direct current link voltage control and PFC operation at alternating current (AC) mains. The speed control is achieved by varying the direct current link voltage of VSI and electronically commutating the BLDC motor using fundamental frequency switching of VSI for reduced switching losses. The proposed PFC-based Luo converter fed BLDC motor drive is designed, and its performance is simulated and validated experimentally for achieving a unity power factor at AC mains over a wide range of speed control at universal AC mains. The achieved power quality indices are observed under the acceptable limits of international power quality standard such as IEC 61000-3-2. Copyright © 2014 John Wiley & Sons, Ltd.

An improved power quality boost-flyback SSIPP fed BLDC motor drive

This paper presents a single-stage isolated power factor corrected power supply (SSIPP) fed permanent magnet brushless DC (BLDC) motor drive. An advantage of fast voltage regulation with single voltage control loop of SSIPP is utilised to develop a power factor correction (PFC) based BLDC motor drive. The speed of BLDC motor is controlled by varying the DC link voltage of the voltage source inverter (VSI) feeding BLDC motor using a single voltage sensor. A boost-flyback SSIPP operating in discontinuous inductor current mode (DICM) is used for the voltage control with improved power quality at AC mains. A fundamental frequency switching of VSI is used instead of pulse width modulation (PWM) switching to avoid high frequency switching losses in it. The performance of the proposed BLDC motor drive is evaluated for wide range of speed control with power quality indices with-in the recommended limits of international power quality standards such as IEC 61000-3-2.