GREP - Grup de Recerca en Electrònica de Potència
http://hdl.handle.net/2117/3399
2024-03-29T12:09:00Z
2024-03-29T12:09:00Z
Comparison of modulations and dc-link balance control strategies for a multibattery charger system based on a three-level dual-active-bridge power converter,
Campos Salazar, José Manuel
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
http://hdl.handle.net/2117/373794
2023-11-12T13:51:36Z
2022-09-30T12:04:07Z
Comparison of modulations and dc-link balance control strategies for a multibattery charger system based on a three-level dual-active-bridge power converter,
Campos Salazar, José Manuel; Busquets Monge, Sergio; Filbà Martínez, Àlber; Alepuz Menéndez, Salvador
This paper focuses on the study of a charger for two batteries connected in series. From the three-phase grid, the batteries are charged through a three-level neutral-point-clamped (NPC) ac-dc converter in cascade with a three-level NPC dualactive-bridge converter. The system provides galvanic isolation and allows bidirectional power flow. A simple control strategy to charge the batteries is considered, based on the regulation of the common- and differential-mode components of the batteries charging currents. In addition, the proposed control system regulates the total dc-link voltage and the dc-link voltage balance in the two systems dc-links. This work is particularly focused on the comparison of the charger performance under two competitive ac-dc converter modulations, in terms of the ac-side voltage harmonic content, the number of switching transitions, the dc-link voltage balance, and the charging current control capacity. Simulation results with the performance comparison are provided and the merits and demerits of each option are highlighted.
© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
2022-09-30T12:04:07Z
Campos Salazar, José Manuel
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
This paper focuses on the study of a charger for two batteries connected in series. From the three-phase grid, the batteries are charged through a three-level neutral-point-clamped (NPC) ac-dc converter in cascade with a three-level NPC dualactive-bridge converter. The system provides galvanic isolation and allows bidirectional power flow. A simple control strategy to charge the batteries is considered, based on the regulation of the common- and differential-mode components of the batteries charging currents. In addition, the proposed control system regulates the total dc-link voltage and the dc-link voltage balance in the two systems dc-links. This work is particularly focused on the comparison of the charger performance under two competitive ac-dc converter modulations, in terms of the ac-side voltage harmonic content, the number of switching transitions, the dc-link voltage balance, and the charging current control capacity. Simulation results with the performance comparison are provided and the merits and demerits of each option are highlighted.
Benefits of finer semiconductor device granularity on power converter thermal stress and MTTF
Rafiezadeh, Roya
Busquets Monge, Sergio
Alepuz Menéndez, Salvador
http://hdl.handle.net/2117/366109
2023-10-15T10:26:46Z
2022-04-20T10:12:50Z
Benefits of finer semiconductor device granularity on power converter thermal stress and MTTF
Rafiezadeh, Roya; Busquets Monge, Sergio; Alepuz Menéndez, Salvador
This article explores the thermal and reliability benefits of configuring the power semiconductor block of power converters with several small standard power semiconductor devices instead of a few larger ones at a fixed total chip area. The effectiveness of a finer power semiconductor device granularity is analyzed in the context of a synchronous buck converter design under different operating conditions and employing a recently proposed component, the switching-cell array, to implement the semiconductor-component block of the converter. Comparative evalua tions are undertaken under different degrees of granularity and in terms of semiconductor loss distribution, semiconductor temperature distribution, and converter mean time to failure. The article also discusses the thermo-electrical and reliability models employed, and the assumptions made for a fair and straightforward comparison in a generic case. The comparison results reveal that a finer granularity can potentially provide remarkable benefits, although the incremental improvements decrease as the granularity becomes finer. A tradeoff solution must be sought in each specific case balancing the benefits achieved with the added complexity
2022-04-20T10:12:50Z
Rafiezadeh, Roya
Busquets Monge, Sergio
Alepuz Menéndez, Salvador
This article explores the thermal and reliability benefits of configuring the power semiconductor block of power converters with several small standard power semiconductor devices instead of a few larger ones at a fixed total chip area. The effectiveness of a finer power semiconductor device granularity is analyzed in the context of a synchronous buck converter design under different operating conditions and employing a recently proposed component, the switching-cell array, to implement the semiconductor-component block of the converter. Comparative evalua tions are undertaken under different degrees of granularity and in terms of semiconductor loss distribution, semiconductor temperature distribution, and converter mean time to failure. The article also discusses the thermo-electrical and reliability models employed, and the assumptions made for a fair and straightforward comparison in a generic case. The comparison results reveal that a finer granularity can potentially provide remarkable benefits, although the incremental improvements decrease as the granularity becomes finer. A tradeoff solution must be sought in each specific case balancing the benefits achieved with the added complexity
A Simple Virtual-Vector-Based PWM Formulation for Multilevel Three-Phase Neutral-Point-Clamped DC–AC Converters including the Overmodulation Region
Busquets Monge, Sergio
http://hdl.handle.net/2117/364299
2022-03-20T17:11:00Z
2022-03-16T16:52:30Z
A Simple Virtual-Vector-Based PWM Formulation for Multilevel Three-Phase Neutral-Point-Clamped DC–AC Converters including the Overmodulation Region
Busquets Monge, Sergio
Neutral-point-clamped (NPC) power conversion topologies are among the most popular multilevel topologies in current industrial products and in industrial and academic research. The proper operation of multilevel three-phase NPC DC–AC converters requires the use of specific pulse-width modulation (PWM) strategies that maintain the DC-link capacitor voltage balance and concurrently optimize various performance factors such as efficiency and harmonic distortion. Although several such PWM strategies have been proposed in the literature, their formulation is often complex and/or covers only particular cases and operating conditions. This manuscript presents a simple formulation of the original virtual-vector-based PWM, which enables capacitor voltage balance in every switching cycle. The formulation is presented, for the general case, in terms of basic phase voltage modulating signals, with no reference to space vectors, involving any number of levels and for any operating conditions, including the overmodulation region. The equivalence of the presented formulation to the original PWM strategy is demonstrated through simulation under different scenarios and operating conditions. Thus, this manuscript offers in a one-stop source a simple, effective, and comprehensive PWM formulation to operate multilevel three-phase NPC DC–AC converters with any number of levels in any operating condition.
2022-03-16T16:52:30Z
Busquets Monge, Sergio
Neutral-point-clamped (NPC) power conversion topologies are among the most popular multilevel topologies in current industrial products and in industrial and academic research. The proper operation of multilevel three-phase NPC DC–AC converters requires the use of specific pulse-width modulation (PWM) strategies that maintain the DC-link capacitor voltage balance and concurrently optimize various performance factors such as efficiency and harmonic distortion. Although several such PWM strategies have been proposed in the literature, their formulation is often complex and/or covers only particular cases and operating conditions. This manuscript presents a simple formulation of the original virtual-vector-based PWM, which enables capacitor voltage balance in every switching cycle. The formulation is presented, for the general case, in terms of basic phase voltage modulating signals, with no reference to space vectors, involving any number of levels and for any operating conditions, including the overmodulation region. The equivalence of the presented formulation to the original PWM strategy is demonstrated through simulation under different scenarios and operating conditions. Thus, this manuscript offers in a one-stop source a simple, effective, and comprehensive PWM formulation to operate multilevel three-phase NPC DC–AC converters with any number of levels in any operating condition.
Multibattery charger system based on a three-level dual-active-bridge power converter
Campos Salazar, José Manuel
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
http://hdl.handle.net/2117/363081
2023-11-12T11:05:03Z
2022-02-25T09:24:51Z
Multibattery charger system based on a three-level dual-active-bridge power converter
Campos Salazar, José Manuel; Busquets Monge, Sergio; Filbà Martínez, Àlber; Alepuz Menéndez, Salvador
A charger for two batteries connected in series is presented in this work. From the three-phase grid, the batteries are charged through a three-level neutral-point-clamped ac-dc converter in cascade with a three-level dual active bridge converter. The system provides galvanic isolation and allows bidirectional power flow. A simple control strategy to charge the batteries is presented, based on the regulation of the commonand differential-mode components of the batteries’ charging currents. With this control approach, each battery bank can be charged independently, allowing it to reach full battery bank capacity, even under different battery initial state-of-charge values or different battery nominal capacities. Moreover, the proposed control system also regulates the total dc-link voltage and the dc-link voltage balance in both dc-links of the system. The simulation results verify the feasibility of the proposed implementation and control system approach.
© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
2022-02-25T09:24:51Z
Campos Salazar, José Manuel
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
A charger for two batteries connected in series is presented in this work. From the three-phase grid, the batteries are charged through a three-level neutral-point-clamped ac-dc converter in cascade with a three-level dual active bridge converter. The system provides galvanic isolation and allows bidirectional power flow. A simple control strategy to charge the batteries is presented, based on the regulation of the commonand differential-mode components of the batteries’ charging currents. With this control approach, each battery bank can be charged independently, allowing it to reach full battery bank capacity, even under different battery initial state-of-charge values or different battery nominal capacities. Moreover, the proposed control system also regulates the total dc-link voltage and the dc-link voltage balance in both dc-links of the system. The simulation results verify the feasibility of the proposed implementation and control system approach.
Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models
Busquets Monge, Sergio
Rafiezadeh, Roya
Alepuz Menéndez, Salvador
Filbà Martínez, Àlber
Nicolás Apruzzese, Joan
http://hdl.handle.net/2117/360473
2023-10-15T07:21:48Z
2022-01-24T11:24:35Z
Fast Reliability Assessment of Neutral-Point-Clamped Topologies through Markov Models
Busquets Monge, Sergio; Rafiezadeh, Roya; Alepuz Menéndez, Salvador; Filbà Martínez, Àlber; Nicolás Apruzzese, Joan
This article presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for a higher number of levels and other topology variants. In addition, this article also proposes an extremely fast calculation method to obtain the precise value of the system's mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. The comparison reveals that multilevel ANPC leg topologies inherently present a potential for higher reliability than the conventional two-level leg, questioning the suitability of the traditional search for topologies with the minimum number of devices in order to improve reliability. Experimental results are presented to validate the fault-tolerance assumptions upon which the presented reliability models for the three-level and four-level ANPC legs are based. This article is accompanied by supplementary MATLAB scripts.
2022-01-24T11:24:35Z
Busquets Monge, Sergio
Rafiezadeh, Roya
Alepuz Menéndez, Salvador
Filbà Martínez, Àlber
Nicolás Apruzzese, Joan
This article presents detailed Markov models for the reliability assessment of multilevel neutral-point-clamped (NPC) converter leg topologies, incorporating their inherent fault-tolerance under open-circuit switch faults. The Markov models are generated and discussed in detail for the three-level and four-level active NPC (ANPC) cases, while the presented methodology can be applied to easily generate the models for a higher number of levels and other topology variants. In addition, this article also proposes an extremely fast calculation method to obtain the precise value of the system's mean time to failure from any given formulated system Markov model. This method is then applied to quantitatively compare the reliability of two-level, three-level, and four-level ANPC legs under switch open-circuit-guaranteed faults and varying degrees of device paralleling. The comparison reveals that multilevel ANPC leg topologies inherently present a potential for higher reliability than the conventional two-level leg, questioning the suitability of the traditional search for topologies with the minimum number of devices in order to improve reliability. Experimental results are presented to validate the fault-tolerance assumptions upon which the presented reliability models for the three-level and four-level ANPC legs are based. This article is accompanied by supplementary MATLAB scripts.
Neutral-point-clamped DC-AC power converters
Busquets Monge, Sergio
http://hdl.handle.net/2117/357098
2021-11-25T12:50:32Z
2021-11-25T12:49:02Z
Neutral-point-clamped DC-AC power converters
Busquets Monge, Sergio
This article reviews the fundamentals of multilevel multiphase neutral-point-clamped DC–AC power converters. These converters are configured with one or more legs and a common DC-link. Each leg is functionally equivalent to a single-pole multiple-throw switch (n¿=¿3 positions) and it is implemented with a combination of only power semiconductor devices. The main leg topologies are initially presented, both active(transistor) clamped and passive(diode) clamped, for any number of levels. The leg switching states enabling all possible leg positions are subsequently discussed. Then, the set of all possible converter switching states and their standard representation in the converter space vector diagram is systematically derived, starting from the simplest converter (single-phase single-leg) up to the most complex converter with an arbitrary number of phases. The space vector diagram is illustrated for three-, four-, and n-levels in the usual single-phase and three-phase cases. Once the converter states have been characterized, the most common converter control approaches are introduced on the basis of the space vector diagram, including space vector control, space vector modulation, programmed pulse width modulation, hysteresis control, and predictive control. These control strategies are illustrated in simple and conventional DC–AC converter configurations. Finally, the article discusses the DC-link capacitor voltage balance problem, which is inherent to these topologies whenever the DC-link is configured with a capacitive voltage divider. The basics of the different solutions to guarantee the balancing are presented, both through the inclusion of additional hardware and through the application of a suitable converter control strategy
2021-11-25T12:49:02Z
Busquets Monge, Sergio
This article reviews the fundamentals of multilevel multiphase neutral-point-clamped DC–AC power converters. These converters are configured with one or more legs and a common DC-link. Each leg is functionally equivalent to a single-pole multiple-throw switch (n¿=¿3 positions) and it is implemented with a combination of only power semiconductor devices. The main leg topologies are initially presented, both active(transistor) clamped and passive(diode) clamped, for any number of levels. The leg switching states enabling all possible leg positions are subsequently discussed. Then, the set of all possible converter switching states and their standard representation in the converter space vector diagram is systematically derived, starting from the simplest converter (single-phase single-leg) up to the most complex converter with an arbitrary number of phases. The space vector diagram is illustrated for three-, four-, and n-levels in the usual single-phase and three-phase cases. Once the converter states have been characterized, the most common converter control approaches are introduced on the basis of the space vector diagram, including space vector control, space vector modulation, programmed pulse width modulation, hysteresis control, and predictive control. These control strategies are illustrated in simple and conventional DC–AC converter configurations. Finally, the article discusses the DC-link capacitor voltage balance problem, which is inherent to these topologies whenever the DC-link is configured with a capacitive voltage divider. The basics of the different solutions to guarantee the balancing are presented, both through the inclusion of additional hardware and through the application of a suitable converter control strategy
Reliability assessment of a fault-tolerant PV multistring inverter
Renaudineau, Hugues Jean-Marie
Paradell-Solà, Pol
Trilla Romero, Lluís
Filbà Martínez, Àlber
Cardoner, David
Domínguez García, José Luis
http://hdl.handle.net/2117/334801
2020-12-22T13:31:26Z
2020-12-22T13:29:41Z
Reliability assessment of a fault-tolerant PV multistring inverter
Renaudineau, Hugues Jean-Marie; Paradell-Solà, Pol; Trilla Romero, Lluís; Filbà Martínez, Àlber; Cardoner, David; Domínguez García, José Luis
In photovoltaic (PV) systems, the reliability of the system components, especially the power converters, is a major concern in obtaining cost effective solutions. In order to guarantee service continuity in the case of failure of elements of the PV converter, in particular, semiconductor switching devices, a solution is to design power converter with fault-tolerance capability. This can be realized by aggregating hardware redundancy on an existing converter, providing the possibility of replacement of faulty elements. This paper evaluates the reliability of a fault-tolerant power electronics converter for PV multistring application. The considered fault-tolerant design includes a single redundant switching leg, which is used in order to reconfigure the structure in case of a switch failure either on DC-AC or DC-DC stages. This paper details the reliability estimation of the considered PV multistring fault-tolerant converter. Furthermore, a comparison with a conventional structure without fault-tolerant capability is provided. The results show that the introduction of a single redundant leg allows for improving the converter mean time to failure by a factor of almost two and it reduces, by half, the power loss due to system-failure shutdowns in PV applications, while only increasing the converter cost by 2–3%.
2020-12-22T13:29:41Z
Renaudineau, Hugues Jean-Marie
Paradell-Solà, Pol
Trilla Romero, Lluís
Filbà Martínez, Àlber
Cardoner, David
Domínguez García, José Luis
In photovoltaic (PV) systems, the reliability of the system components, especially the power converters, is a major concern in obtaining cost effective solutions. In order to guarantee service continuity in the case of failure of elements of the PV converter, in particular, semiconductor switching devices, a solution is to design power converter with fault-tolerance capability. This can be realized by aggregating hardware redundancy on an existing converter, providing the possibility of replacement of faulty elements. This paper evaluates the reliability of a fault-tolerant power electronics converter for PV multistring application. The considered fault-tolerant design includes a single redundant switching leg, which is used in order to reconfigure the structure in case of a switch failure either on DC-AC or DC-DC stages. This paper details the reliability estimation of the considered PV multistring fault-tolerant converter. Furthermore, a comparison with a conventional structure without fault-tolerant capability is provided. The results show that the introduction of a single redundant leg allows for improving the converter mean time to failure by a factor of almost two and it reduces, by half, the power loss due to system-failure shutdowns in PV applications, while only increasing the converter cost by 2–3%.
Multibattery-fed neutral-point-clamped DC-AC converter with SoC balancing control to maximize capacity utilization
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
Nicolás Apruzzese, Joan
Luque Acera, Adrià
Conesa Roca, Alfons
Bordonau Farrerons, José
http://hdl.handle.net/2117/333553
2023-09-10T11:10:28Z
2020-12-01T07:32:37Z
Multibattery-fed neutral-point-clamped DC-AC converter with SoC balancing control to maximize capacity utilization
Busquets Monge, Sergio; Filbà Martínez, Àlber; Alepuz Menéndez, Salvador; Nicolás Apruzzese, Joan; Luque Acera, Adrià; Conesa Roca, Alfons; Bordonau Farrerons, José
This paper studies a multilevel multiphase dc-ac conversion system configured by a neutral-point-clamped converter fed by multiple battery packs connected in series. A virtual-vector modulation is selected and a state-of-charge (SoC) balancing control is designed to be able to employ the full battery bank capacity, even under different battery initial SoC values or different battery nominal capacities. The SoC balancing among battery packs is accomplished through the multilevel converter operation in a lossless manner, by simply distributing the dc-to-ac power flow among the batteries according to their SoC. A simple average system model is also presented, which allows performing very fast system simulations over long periods of time and serves as a convenient tool to tune the compensator parameters. The satisfactory performance of the proposed system configuration and control, which can be applied with any number of levels and phases, has been verified through simulations and experiments in a four-level three-phase dc-ac converter fed by three lithium-ion battery packs. The results prove the feasibility and advantages of the proposed system configuration, which can be used to implement conversion systems with different specifications combining several instances of a standard battery pack and a standard power semiconductor device
2020-12-01T07:32:37Z
Busquets Monge, Sergio
Filbà Martínez, Àlber
Alepuz Menéndez, Salvador
Nicolás Apruzzese, Joan
Luque Acera, Adrià
Conesa Roca, Alfons
Bordonau Farrerons, José
This paper studies a multilevel multiphase dc-ac conversion system configured by a neutral-point-clamped converter fed by multiple battery packs connected in series. A virtual-vector modulation is selected and a state-of-charge (SoC) balancing control is designed to be able to employ the full battery bank capacity, even under different battery initial SoC values or different battery nominal capacities. The SoC balancing among battery packs is accomplished through the multilevel converter operation in a lossless manner, by simply distributing the dc-to-ac power flow among the batteries according to their SoC. A simple average system model is also presented, which allows performing very fast system simulations over long periods of time and serves as a convenient tool to tune the compensator parameters. The satisfactory performance of the proposed system configuration and control, which can be applied with any number of levels and phases, has been verified through simulations and experiments in a four-level three-phase dc-ac converter fed by three lithium-ion battery packs. The results prove the feasibility and advantages of the proposed system configuration, which can be used to implement conversion systems with different specifications combining several instances of a standard battery pack and a standard power semiconductor device
High–efficiency power amplifiers
Velasco Quesada, Guillermo
Martínez García, Herminio
Conesa Roca, Alfons
http://hdl.handle.net/2117/181593
2020-07-23T20:36:38Z
2020-03-26T13:11:55Z
High–efficiency power amplifiers
Velasco Quesada, Guillermo; Martínez García, Herminio; Conesa Roca, Alfons
This chapter describes amplifiers or amplification output stages that are capable of delivering high-output power levels. Since power amplifier stages may deliver high output power to low-impedance loads, they are significantly different from the low-power small signal amplifiers. Class-A operation is the only configuration that will yield low distortion signals. Class-B and class-AB power amplifiers assure signal continuity by making use of arrangements of two transistors that allow each transistor to share portions of the input signal conduction angle. The high-efficiency amplifiers based on this approach are usually classified as class-D, class-E and class-F, being also referred to as switching amplifiers or digital amplifiers. To compare the design of power amplifiers, different figures of merit or parameters can be utilized. Large input signal to power amplifiers causes the amplifier to yield distorted output signals. In fact, in large-signal operation, the signals overtake the limits of the transistor forward-active region, causing distortion at the output.
2020-03-26T13:11:55Z
Velasco Quesada, Guillermo
Martínez García, Herminio
Conesa Roca, Alfons
This chapter describes amplifiers or amplification output stages that are capable of delivering high-output power levels. Since power amplifier stages may deliver high output power to low-impedance loads, they are significantly different from the low-power small signal amplifiers. Class-A operation is the only configuration that will yield low distortion signals. Class-B and class-AB power amplifiers assure signal continuity by making use of arrangements of two transistors that allow each transistor to share portions of the input signal conduction angle. The high-efficiency amplifiers based on this approach are usually classified as class-D, class-E and class-F, being also referred to as switching amplifiers or digital amplifiers. To compare the design of power amplifiers, different figures of merit or parameters can be utilized. Large input signal to power amplifiers causes the amplifier to yield distorted output signals. In fact, in large-signal operation, the signals overtake the limits of the transistor forward-active region, causing distortion at the output.
Generic design and implementation of multi-cell multi-phase voltage source inverters
Busquets Monge, Sergio
Nicolás Apruzzese, Joan
http://hdl.handle.net/2117/180980
2023-09-10T13:46:09Z
2020-03-24T08:19:58Z
Generic design and implementation of multi-cell multi-phase voltage source inverters
Busquets Monge, Sergio; Nicolás Apruzzese, Joan
This paper deals with generic design and implementation of multi-cell multi-level multi-phase voltage source inverters. Based on a well-known topology, the paper focuses on place and route design to enable V and/or I scalability while ensuring high performance and high power densities. The topology is studied to define how conversion cells should be designed to ease and automate scalability in I and V. A prototype is built and tested, and the performances are benchmarked
2020-03-24T08:19:58Z
Busquets Monge, Sergio
Nicolás Apruzzese, Joan
This paper deals with generic design and implementation of multi-cell multi-level multi-phase voltage source inverters. Based on a well-known topology, the paper focuses on place and route design to enable V and/or I scalability while ensuring high performance and high power densities. The topology is studied to define how conversion cells should be designed to ease and automate scalability in I and V. A prototype is built and tested, and the performances are benchmarked