EPE Association: EPE 2011 - DS1h: Topic 06: Converter Control Sets and Modulation Strategies

EPE 2011 - DS1h: Topic 06: Converter Control Sets and Modulation Strategies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 06: Modulation Strategies and Specific Control Methods for Static Converters > EPE 2011 - DS1h: Topic 06: Converter Control Sets and Modulation Strategies

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   A CURRENT SYMMETRICAL HYBRID MULTILEVEL DC-AC CONVERTER
By Samir Ahmad MUSSA, Tiago Kommers JAPPE, Marcelo Lobo HELDWEIN, Domingo Ruiz CABALLERO, Carlos PAREDES [View]
[Download]

Abstract: This work presents the analysis of new symmetrical hybrid current source-type multilevel inverter topologies. A three-level current cell (TCC) and its respective modulation pattern are proposed. The purpose of the circuits presented here is to reduce current stresses that affects the power semiconductor devices and improve harmonic distortion of the voltages applied to the load. This is done by distributing currents among the switches in the three-level cell. As a characteristic of the proposed cells, some of the switches operate at low frequency while others are switched at high frequency. To validate the operating principle a single-phase circuit has been simulated, operating at 1.0 kHz for the fast switches and 50 Hz for the slow switches. Also featured in this paper is the extension to three-phase versions of the proposed converter.

   A New Unequal DC link Voltage Configuration for a Single Phase Multilevel Converter to Reduce Low Order Harmonics
By Negareh GHASEMI, Firuz ZARE, Christian LANGTON, Arindam GHOSH [View]
[Download]

Abstract: Multilevel converters are used in high power and high voltage applications due to their attractivebenefits in generating high quality output voltage. Increasing the number of voltage levels can lead toa reduction in lower order harmonics. Various modulation and control techniques are introduced formultilevel converters like Space Vector Modulation (SVM), Sinusoidal Pulse Width Modulation(SPWM) and Harmonic Elimination (HE) methods. Multilevel converters may have a DC link withequal or unequal DC voltages. In this paper a new modulation technique based on harmonicelimination method is proposed for those multilevel converters that have unequal DC link voltages.This new technique has better effect on output voltage quality and less Total Harmonic Distortion(THD) than other modulation techniques. In order to verify the proposed modulation technique,MATLAB simulations are carried out for a single-phase diode-clamped inverter.

   A PWM strategy dedicated to RMS current reduction in DC link capacitor of an embedded three phase inverter
By Thê Dung NGUYEN, Nicolas PATIN, Guy FRIEDRICH [View]
[Download]

Abstract: This article presents an extension of the Double Carrier Pulse Width Modulation strategy (DCPWM)presented in [1] called Extented DCPWM (Ext-DCPWM) strategy aiming at reducing the RMS currentowing through DC link ltering capacitors on embedded systems. Instead of utilizing two adjacentactive vectors as classic PWM strategies, this new strategy utilizes two non-adjacent active vectors in thecase of low modulation index or three consecutive active vectors in the case of high modulation index.Analytical calculations show that this new strategy is particularly eective in terms of ltering capacitorRMS current for high power factor compared to space vector PWM (SVPWM) which is used as thestrategy of reference. It is also shown that induced switching losses of this new strategy can be 50\%lower than that of SVPWM. The implementation on DSP boards can be done easily with help of currentsensors.

   A Space Vector PWM Algorithm for a Three-Level Seven-Phase Voltage Source Inverter
By Emil LEVI, Obrad DORDEVIC, Martin JONES [View]
[Download]

Abstract: The paper develops for the first time a space vector PWM technique for a seven-phase, three-level voltage source inverter (VSI), based on vector space decomposition (VSD). The algorithm represents an extension of a recently introduced VSD-based space vector algorithm for a three-level five-phase VSI. However, due to the increase of the phase number from five to seven, which simultaneously increases the number of planes that have to be considered from two to three and the number of switching states from 35 = 243 to 37 = 2187, the development of the space vector PWM is here much more involved. Using the ordering-per-sector law in time domain, the number of switching states that have to be considered is reduced to an acceptable number of 297. Choice of switching sequences and division of sectors into sub-sectors are further done in such a manner that space vector projection cancelation in the second and the third plane is achieved, where the references are zero. Each of the fourteen sectors in the first plane (with non-zero reference) is divided into 18 sub-sectors, meaning that each sector is characterised with 18 specific switching sequences. Developed space vector PWM method requires a lot of preliminary calculations for selection of sequences and for sub-division of sectors, but the algorithm is rather straightforward. Once when the appropriate constants have been established, development of the software for real-time implementation is simple. Validity and implementation simplicity of the proposed algorithm are proved at this stage by simulations.

   Analysis of Space Vector Modulation Techniques Applied in Voltage Source Converters of Ultrahigh Speed Induction Motor Drives
By Peter STUMPF, Istvan NAGY, Rafael Kalman JARDAN, Zoltan VARGA [View]
[Download]

Abstract: The paper investigates the Space Vector Modulation (SVM) technique applied in Voltage Source Converter(VSC) supplying Ultrahigh Speed Induction Machine (USIM). Two different sampling techniques,the Regular Sampled (RS) and the Naturally Sampled (NS) are investigated by simulations and tests. Itwas found that subharmonic flux with considerable amplitudes can be generated in USIM, which couldlead to the damage of the USIM. The paper focuses on the generation of subharmonics. A digitallyimplemented NS-SVM algorithm is also introduced in the paper.

   Control of the Modular Multi-Level Converter for Minimized Cell Capacitance
By Stefan P. ENGEL, Rik W. DE DONCKER [View]
[Download]

Abstract: The Modular Multi-Level Converter (M2C) is an emerging multi-level topology for medium-voltage inverters. The drawback of this topology is the high expense on capacitors in the inverter cells. This paper describes a method to minimize the required cell capacitance for a given point of operation (modulation index, displacement factor) by means of injecting harmonics into the circulating current. The required cell capacitance is significantly reduced by the proposed method.

   Evolutive Discontinuous SVM for Variable Speed Electric Drive
By Hamid KHAN, Youssef TOUZANI, Khalil El Khamlichi DRISSI [View]
[Download]

Abstract: Space Vector Modulation (SVM), with its many advantages over classical Pulse Width Modulation (PWM) techniques, is gaining popularity. Different Discontinuous-PWM with harmonic injections were developed during the past few years with the objective of reducing switching losses in power converters. However discontinuous modulation based on space vector calculations tends to be more complicated than injecting zero sequence voltage with the required phase angle. The proposed method extends the DPWM concept to tackle the temperature imbalance amongst the inverter legs and optimize switching losses for unbalanced loads. Switching losses also mean increased thermal stress on the power switches, which reduces the life of the power switches and requires an appropriate cooling system. A discontinuous auto-adjusting SVM technique intended for HEV oriented Electric-Drives is presented in this paper.

   Gating Signal Generator for Multiphase Voltage Source Inverters Using Space Vector PWM
By Jwu-Sheng HU, Keng yuan CHEN, Chi-Him TANG , Te-Yang SHEN [View]
[Download]

Abstract: This work systematically analyzes space vector pulse-width modulation (PWM) for a multiphasevoltage source inverter (VSI). The instantaneous output voltages of the VSI, which are called spacevectors, can be classified according to the switching states of the VSI. By applying the eigen-spacedecomposition of the system matrix, the n-phase VSI control problem can be solved analytically. Thisanalysis leads to a switching strategy that uses the fewest space vectors and minimum total conductiontime. This yields a maximum linear modulation index and minimum switching number. The analysisreveals that the implementation of the modulator needs only adders and comparators and thecomputation complexity is independent of the phase number. Simulation results confirm theeffectiveness of the proposed algorithm.

   Generalized Integration Duty Cycle Conversion Pulse-Width Modulation (IPWM) Algorithm for Multilevel-PV DC-Link Inverter
By Imadeddin ABDALLA [View]
[Download]

Abstract: In this paper the 3-level integration PWM is developed to a simplified generalized PWM algorithmwhich can be used to control higher level photovoltaic (PV) inverters. The proposed algorithm isimplemented practically by using eZdsp™ F28335 to control the multi-level DC-link inverter and tomaintain the operation of input PV sources at their maximum power point (MPP). The inverter hasbeen tested under different loads and irradiance conditions and the obtained results are verified bycomparison with the space-vector PWM (SVPWM) strategy. The introduced algorithm is simple forimplementation and produces satisfactory results in the open and closed-loop systems.

   Model Predictive Current Controller for Four-Leg Converters under Unbalanced Conditions
By Aziz Choubail ZIANI, Ana M. LLOR, Maurice FADEL [View]
[Download]

Abstract: In this paper, current predictive controller is proposed for grid connected 4-leg VSCs which generatescontrol signals without voltage reference calculation. This direct control of switch control signals isbased on geometrical approach where the predicted and reference currents are projected in a 3-Dspace. To reach the reference, an association of three active control and two null vectors is used. Thisassociation constitutes a control profile. The profile projections divide the action zone of the converterinto 24 different volumes. The appropriate control profile is selected according to a criterionoptimization. For this task, geometrical properties of current projections are used.

   Parametric Study of Dead Time Effect on Three Phase AC Output Impedance of Voltage Source Inverter (VSI)
By ZHIYU SHEN, Marko JAKSIC, Sara AHMED, Paolo MATTAVELLI, Dushan BOROYEVICH [View]
[Download]

Abstract: This paper reports that the output impedance of a VSI measured in experiments differs from the results derived from the traditional small-signal model known in the literature. A parametric study of this effect is conducted by simulation, and then verified by experiment. The result reveals that dead time is the main contributor to the difference in impedance between simulation and experimentation. Dead time adds a resistive part to the VSI output impedance.

   Power Conditioning System with Cascaded H-Bridge Multilevel Converter – DC-link Voltage Balancing Method
By Marcin ZYGMANOWSKI, Boguslaw GRZESIK, Jaroslaw MICHALAK [View]
[Download]

Abstract: Multilevel converters have become an attractive choice for high voltage and high power applications. One of the most popular multilevel converter topologies is the cascaded H-bridge converter. Besides its simplicity this topology requires separate DC sources. In electric drive applications these DC sources are normally performed by multi-winding transformers with diode rectifiers. In STATCOM or PWM rectifiers there is no need to utilize multi-winding transformers but the DC-link is distributed. This feature can be exploited in the power conditioning system (PCS) with distri¬buted energy storage e.g. supercapacitors. The paper focuses on the DC-link voltage balancing method in the multilevel cascaded H-bridge converter. This method is based on additional voltage components generated at the output of the cascaded H-bridge converter. It is assumed that the proposed method does not affect the AC-side currents of the PCS. Inserting the voltage components of fundamental frequency, together with AC-side currents, allows exchanging active power between the H-bridge converters and results in balancing the DC-link voltages. In the paper, balancing voltage components are distinguished into two types. The first components can balance DC-link voltages in each phase of the cascaded H-bridge converter separately and the second components allow exchanging the energy between the phases

   Space Vector Modulation Scheme for Six-Switch Two Three-Phase Output Inverter
By Nobukazu HOSHI, Tomohisa OGAWA [View]
[Download]

Abstract: Several three-phase inverters which have two three-phase outputs with less number of switching devices have been proposed. A six-switch two three-phase outputs inverter (six-switch inverter is used as the abbreviation) have been proposed as one of the inverters. In addition, pulse width modulation (PWM) scheme for the inverter was proposed. However, in PWM scheme, switching frequency of the middle arm devices is twice as high as that of the other devices. As a solution of the problem, instantaneous current control (ICC) method was proposed. ICC requires current sensors and the THD of the output current was not so good in the previous work. Then, this paper proposes a space vector modulation (SVM) scheme for six-switch inverter. In addition, the characteristics of the scheme are verified by simulations. Moreover, controller configuration of the proposed SVM scheme and experimental verification using the controller are described.

   Space Vector Modulation Scheme to Minimize Common-Mode Voltage generated by a Three-Phase Hybrid Multilevel Inverter
By Tiago Kommers JAPPE, Samir Ahmad MUSSA, Marcelo Lobo HELDWEIN, Domingo Ruiz CABALLERO, Antonio CASTILLO [View]
[Download]

Abstract: This paper proposes the implementation of a space vector modulation (SVM) scheme to reduce thecommon-mode voltage of a symmetrical hybrid five-level inverter operating at high modulation index.The proposed modulation is implemented in a DSC–Digital Signal Controller. It employs vectors thatprevent voltage vectors that impose high common-mode voltages at the converter load. Experimentalresults are presented in order to validate the proposed modulation scheme.

   Space Vector Modulation Strategy applied to Interphase Transformers-based Five-Level Current Source Inverters for Electric Propulsion
By Bruno DUPCZAK, Marcelo HELDWEIN, Arnaldo PERIN [View]
[Download]

Abstract: A propulsion system based on the multilevel current source inverter (MCSI), which enables voltage-boosting and high current handling capabilities, is an interesting solution for electric propulsion. In sucha system, the associated capacitance values are small and the voltages at the motor terminals are nearly sinusoidal. Such a MCSI employing interphase transformers to produce different input current levels presents the advantage that the employed magnetic cores are separately optimized and volume reduction is achievable through the choice of proper magnetic core materials. However, a suitable modulation strategy is required to minimize input and output ripples, while providing input dc currents balancing, high quality load voltages, reduced dc and/or low frequency voltage components at the interphase transformers and good losses distribution among the power semiconductors. This work proposes a novel space vector modulation strategy that addresses these challenges.

   The Application of the SHE-PWM Based on Particle Swarm Optimization for the Improvement of the Cascaded H-Bridges Inverter Output Voltage
By Abdellah KOUZOU, Stolze PETER, Mohaned Oulhadj MAHMOUDI, Mohamed Seghir BOUCHERIT, Ralph KENNEL [View]
[Download]

Abstract: In the present work Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM)based on Particle Swarm Optimization is proposed for the enhancement of the H-Bridge multilevelinverter output voltage quality. The problem of the SHE-PWM is presented by a constrained nonlinearobjective function which has to be minimized. The main aim is the calculation of the switching anglesvector solution representing the best minimal value for the objective function. The results obtainedwith the present application show the effectiveness of the proposed method.

EPE 2011 - DS1h: Topic 06: Converter Control Sets and Modulation Strategies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 06: Modulation Strategies and Specific Control Methods for Static Converters > EPE 2011 - DS1h: Topic 06: Converter Control Sets and Modulation Strategies
	[return to parent folder]

	A CURRENT SYMMETRICAL HYBRID MULTILEVEL DC-AC CONVERTER By Samir Ahmad MUSSA, Tiago Kommers JAPPE, Marcelo Lobo HELDWEIN, Domingo Ruiz CABALLERO, Carlos PAREDES	[View] [Download]
Abstract: This work presents the analysis of new symmetrical hybrid current source-type multilevel inverter topologies. A three-level current cell (TCC) and its respective modulation pattern are proposed. The purpose of the circuits presented here is to reduce current stresses that affects the power semiconductor devices and improve harmonic distortion of the voltages applied to the load. This is done by distributing currents among the switches in the three-level cell. As a characteristic of the proposed cells, some of the switches operate at low frequency while others are switched at high frequency. To validate the operating principle a single-phase circuit has been simulated, operating at 1.0 kHz for the fast switches and 50 Hz for the slow switches. Also featured in this paper is the extension to three-phase versions of the proposed converter.

	A New Unequal DC link Voltage Configuration for a Single Phase Multilevel Converter to Reduce Low Order Harmonics By Negareh GHASEMI, Firuz ZARE, Christian LANGTON, Arindam GHOSH	[View] [Download]
Abstract: Multilevel converters are used in high power and high voltage applications due to their attractivebenefits in generating high quality output voltage. Increasing the number of voltage levels can lead toa reduction in lower order harmonics. Various modulation and control techniques are introduced formultilevel converters like Space Vector Modulation (SVM), Sinusoidal Pulse Width Modulation(SPWM) and Harmonic Elimination (HE) methods. Multilevel converters may have a DC link withequal or unequal DC voltages. In this paper a new modulation technique based on harmonicelimination method is proposed for those multilevel converters that have unequal DC link voltages.This new technique has better effect on output voltage quality and less Total Harmonic Distortion(THD) than other modulation techniques. In order to verify the proposed modulation technique,MATLAB simulations are carried out for a single-phase diode-clamped inverter.

	A PWM strategy dedicated to RMS current reduction in DC link capacitor of an embedded three phase inverter By Thê Dung NGUYEN, Nicolas PATIN, Guy FRIEDRICH	[View] [Download]
Abstract: This article presents an extension of the Double Carrier Pulse Width Modulation strategy (DCPWM)presented in [1] called Extented DCPWM (Ext-DCPWM) strategy aiming at reducing the RMS currentowing through DC link ltering capacitors on embedded systems. Instead of utilizing two adjacentactive vectors as classic PWM strategies, this new strategy utilizes two non-adjacent active vectors in thecase of low modulation index or three consecutive active vectors in the case of high modulation index.Analytical calculations show that this new strategy is particularly eective in terms of ltering capacitorRMS current for high power factor compared to space vector PWM (SVPWM) which is used as thestrategy of reference. It is also shown that induced switching losses of this new strategy can be 50\%lower than that of SVPWM. The implementation on DSP boards can be done easily with help of currentsensors.

	A Space Vector PWM Algorithm for a Three-Level Seven-Phase Voltage Source Inverter By Emil LEVI, Obrad DORDEVIC, Martin JONES	[View] [Download]
Abstract: The paper develops for the first time a space vector PWM technique for a seven-phase, three-level voltage source inverter (VSI), based on vector space decomposition (VSD). The algorithm represents an extension of a recently introduced VSD-based space vector algorithm for a three-level five-phase VSI. However, due to the increase of the phase number from five to seven, which simultaneously increases the number of planes that have to be considered from two to three and the number of switching states from 35 = 243 to 37 = 2187, the development of the space vector PWM is here much more involved. Using the ordering-per-sector law in time domain, the number of switching states that have to be considered is reduced to an acceptable number of 297. Choice of switching sequences and division of sectors into sub-sectors are further done in such a manner that space vector projection cancelation in the second and the third plane is achieved, where the references are zero. Each of the fourteen sectors in the first plane (with non-zero reference) is divided into 18 sub-sectors, meaning that each sector is characterised with 18 specific switching sequences. Developed space vector PWM method requires a lot of preliminary calculations for selection of sequences and for sub-division of sectors, but the algorithm is rather straightforward. Once when the appropriate constants have been established, development of the software for real-time implementation is simple. Validity and implementation simplicity of the proposed algorithm are proved at this stage by simulations.

	Analysis of Space Vector Modulation Techniques Applied in Voltage Source Converters of Ultrahigh Speed Induction Motor Drives By Peter STUMPF, Istvan NAGY, Rafael Kalman JARDAN, Zoltan VARGA	[View] [Download]
Abstract: The paper investigates the Space Vector Modulation (SVM) technique applied in Voltage Source Converter(VSC) supplying Ultrahigh Speed Induction Machine (USIM). Two different sampling techniques,the Regular Sampled (RS) and the Naturally Sampled (NS) are investigated by simulations and tests. Itwas found that subharmonic flux with considerable amplitudes can be generated in USIM, which couldlead to the damage of the USIM. The paper focuses on the generation of subharmonics. A digitallyimplemented NS-SVM algorithm is also introduced in the paper.

	Control of the Modular Multi-Level Converter for Minimized Cell Capacitance By Stefan P. ENGEL, Rik W. DE DONCKER	[View] [Download]
Abstract: The Modular Multi-Level Converter (M2C) is an emerging multi-level topology for medium-voltage inverters. The drawback of this topology is the high expense on capacitors in the inverter cells. This paper describes a method to minimize the required cell capacitance for a given point of operation (modulation index, displacement factor) by means of injecting harmonics into the circulating current. The required cell capacitance is significantly reduced by the proposed method.

	Evolutive Discontinuous SVM for Variable Speed Electric Drive By Hamid KHAN, Youssef TOUZANI, Khalil El Khamlichi DRISSI	[View] [Download]
Abstract: Space Vector Modulation (SVM), with its many advantages over classical Pulse Width Modulation (PWM) techniques, is gaining popularity. Different Discontinuous-PWM with harmonic injections were developed during the past few years with the objective of reducing switching losses in power converters. However discontinuous modulation based on space vector calculations tends to be more complicated than injecting zero sequence voltage with the required phase angle. The proposed method extends the DPWM concept to tackle the temperature imbalance amongst the inverter legs and optimize switching losses for unbalanced loads. Switching losses also mean increased thermal stress on the power switches, which reduces the life of the power switches and requires an appropriate cooling system. A discontinuous auto-adjusting SVM technique intended for HEV oriented Electric-Drives is presented in this paper.

	Gating Signal Generator for Multiphase Voltage Source Inverters Using Space Vector PWM By Jwu-Sheng HU, Keng yuan CHEN, Chi-Him TANG , Te-Yang SHEN	[View] [Download]
Abstract: This work systematically analyzes space vector pulse-width modulation (PWM) for a multiphasevoltage source inverter (VSI). The instantaneous output voltages of the VSI, which are called spacevectors, can be classified according to the switching states of the VSI. By applying the eigen-spacedecomposition of the system matrix, the n-phase VSI control problem can be solved analytically. Thisanalysis leads to a switching strategy that uses the fewest space vectors and minimum total conductiontime. This yields a maximum linear modulation index and minimum switching number. The analysisreveals that the implementation of the modulator needs only adders and comparators and thecomputation complexity is independent of the phase number. Simulation results confirm theeffectiveness of the proposed algorithm.

	Generalized Integration Duty Cycle Conversion Pulse-Width Modulation (IPWM) Algorithm for Multilevel-PV DC-Link Inverter By Imadeddin ABDALLA	[View] [Download]
Abstract: In this paper the 3-level integration PWM is developed to a simplified generalized PWM algorithmwhich can be used to control higher level photovoltaic (PV) inverters. The proposed algorithm isimplemented practically by using eZdsp™ F28335 to control the multi-level DC-link inverter and tomaintain the operation of input PV sources at their maximum power point (MPP). The inverter hasbeen tested under different loads and irradiance conditions and the obtained results are verified bycomparison with the space-vector PWM (SVPWM) strategy. The introduced algorithm is simple forimplementation and produces satisfactory results in the open and closed-loop systems.

	Model Predictive Current Controller for Four-Leg Converters under Unbalanced Conditions By Aziz Choubail ZIANI, Ana M. LLOR, Maurice FADEL	[View] [Download]
Abstract: In this paper, current predictive controller is proposed for grid connected 4-leg VSCs which generatescontrol signals without voltage reference calculation. This direct control of switch control signals isbased on geometrical approach where the predicted and reference currents are projected in a 3-Dspace. To reach the reference, an association of three active control and two null vectors is used. Thisassociation constitutes a control profile. The profile projections divide the action zone of the converterinto 24 different volumes. The appropriate control profile is selected according to a criterionoptimization. For this task, geometrical properties of current projections are used.

	Parametric Study of Dead Time Effect on Three Phase AC Output Impedance of Voltage Source Inverter (VSI) By ZHIYU SHEN, Marko JAKSIC, Sara AHMED, Paolo MATTAVELLI, Dushan BOROYEVICH	[View] [Download]
Abstract: This paper reports that the output impedance of a VSI measured in experiments differs from the results derived from the traditional small-signal model known in the literature. A parametric study of this effect is conducted by simulation, and then verified by experiment. The result reveals that dead time is the main contributor to the difference in impedance between simulation and experimentation. Dead time adds a resistive part to the VSI output impedance.

	Power Conditioning System with Cascaded H-Bridge Multilevel Converter – DC-link Voltage Balancing Method By Marcin ZYGMANOWSKI, Boguslaw GRZESIK, Jaroslaw MICHALAK	[View] [Download]
Abstract: Multilevel converters have become an attractive choice for high voltage and high power applications. One of the most popular multilevel converter topologies is the cascaded H-bridge converter. Besides its simplicity this topology requires separate DC sources. In electric drive applications these DC sources are normally performed by multi-winding transformers with diode rectifiers. In STATCOM or PWM rectifiers there is no need to utilize multi-winding transformers but the DC-link is distributed. This feature can be exploited in the power conditioning system (PCS) with distri¬buted energy storage e.g. supercapacitors. The paper focuses on the DC-link voltage balancing method in the multilevel cascaded H-bridge converter. This method is based on additional voltage components generated at the output of the cascaded H-bridge converter. It is assumed that the proposed method does not affect the AC-side currents of the PCS. Inserting the voltage components of fundamental frequency, together with AC-side currents, allows exchanging active power between the H-bridge converters and results in balancing the DC-link voltages. In the paper, balancing voltage components are distinguished into two types. The first components can balance DC-link voltages in each phase of the cascaded H-bridge converter separately and the second components allow exchanging the energy between the phases

	Space Vector Modulation Scheme for Six-Switch Two Three-Phase Output Inverter By Nobukazu HOSHI, Tomohisa OGAWA	[View] [Download]
Abstract: Several three-phase inverters which have two three-phase outputs with less number of switching devices have been proposed. A six-switch two three-phase outputs inverter (six-switch inverter is used as the abbreviation) have been proposed as one of the inverters. In addition, pulse width modulation (PWM) scheme for the inverter was proposed. However, in PWM scheme, switching frequency of the middle arm devices is twice as high as that of the other devices. As a solution of the problem, instantaneous current control (ICC) method was proposed. ICC requires current sensors and the THD of the output current was not so good in the previous work. Then, this paper proposes a space vector modulation (SVM) scheme for six-switch inverter. In addition, the characteristics of the scheme are verified by simulations. Moreover, controller configuration of the proposed SVM scheme and experimental verification using the controller are described.

	Space Vector Modulation Scheme to Minimize Common-Mode Voltage generated by a Three-Phase Hybrid Multilevel Inverter By Tiago Kommers JAPPE, Samir Ahmad MUSSA, Marcelo Lobo HELDWEIN, Domingo Ruiz CABALLERO, Antonio CASTILLO	[View] [Download]
Abstract: This paper proposes the implementation of a space vector modulation (SVM) scheme to reduce thecommon-mode voltage of a symmetrical hybrid five-level inverter operating at high modulation index.The proposed modulation is implemented in a DSC–Digital Signal Controller. It employs vectors thatprevent voltage vectors that impose high common-mode voltages at the converter load. Experimentalresults are presented in order to validate the proposed modulation scheme.

	Space Vector Modulation Strategy applied to Interphase Transformers-based Five-Level Current Source Inverters for Electric Propulsion By Bruno DUPCZAK, Marcelo HELDWEIN, Arnaldo PERIN	[View] [Download]
Abstract: A propulsion system based on the multilevel current source inverter (MCSI), which enables voltage-boosting and high current handling capabilities, is an interesting solution for electric propulsion. In sucha system, the associated capacitance values are small and the voltages at the motor terminals are nearly sinusoidal. Such a MCSI employing interphase transformers to produce different input current levels presents the advantage that the employed magnetic cores are separately optimized and volume reduction is achievable through the choice of proper magnetic core materials. However, a suitable modulation strategy is required to minimize input and output ripples, while providing input dc currents balancing, high quality load voltages, reduced dc and/or low frequency voltage components at the interphase transformers and good losses distribution among the power semiconductors. This work proposes a novel space vector modulation strategy that addresses these challenges.

	The Application of the SHE-PWM Based on Particle Swarm Optimization for the Improvement of the Cascaded H-Bridges Inverter Output Voltage By Abdellah KOUZOU, Stolze PETER, Mohaned Oulhadj MAHMOUDI, Mohamed Seghir BOUCHERIT, Ralph KENNEL	[View] [Download]
Abstract: In the present work Selective Harmonic Elimination Pulse Width Modulation (SHE-PWM)based on Particle Swarm Optimization is proposed for the enhancement of the H-Bridge multilevelinverter output voltage quality. The problem of the SHE-PWM is presented by a constrained nonlinearobjective function which has to be minimized. The main aim is the calculation of the switching anglesvector solution representing the best minimal value for the objective function. The results obtainedwith the present application show the effectiveness of the proposed method.