Query: loss balancing SVPWM for active NPC converters

Candidate papers:

abstract: This paper presents a novel loss balancing modulation method for more evenly distributing semiconductor losses in multilevel active neutral point clamped (ANPC) converters. The presented method is achieved by optimally utilizing the redundant switching states of space vector pulse width modulation (SVPWM) in ANPC converters. A comparison of the effect of losses distribution between the proposed loss balancing SVPWM (LB SVPWM) method and the conventional phase shifted PWM (PS PWM) methods is carried out in simulation. The effectiveness of the presented LB SVPWM method is also verified in ANPC converters based on all SiC MOSFETs. The results show that the proposed method can distribute the device losses more evenly, especially for all SiC based ANPC converters, which can in turn improve the output power capacity and switching frequency. In addition, with utilization of the introduced loss balancing SVPWM method in ANPC converters, 15% higher output voltage and lower harmonic distortion can be achieved compared to PS PWM modulated ANPC converters.
author_names: Xin Jing

Jiangbiao He

Nabeel A O Demerdash
title: Loss balancing SVPWM for active NPC converters
venue: 2014 IEEE Applied Power Electronics Conference and Exposition APEC 2014
year: 2014

abstract: The three level neutral point clamped (NPC) converter has attracted much attention in high power medium voltage applications, but it is well known that the NPC topology suffers from unequal power loss distribution among its semiconductor devices. The power loss unbalance problem becomes especially severe when the converter is operating at low fundamental frequencies. To overcome the loss unbalance problem of the NPC converter, the active NPC (ANPC) technique was introduced. However, it is demonstrated in this paper that in many cases, the conventional modulation method for the ANPC converter only marginally relieves the loss unbalance problem. This paper proposes a new modulation scheme (named the adaptive doubled frequency modulation) for the three level ANPC converter, which significantly improves the power loss and thermal sharing among the semiconductor devices. The basic idea of the proposed scheme is adaptively adjusting the duty cycles of the switching states for every switching cycle, so as to optimize the power loss distribution. Simulation and experimental results verify this new method.
author_names: Yi Deng

Jun Li

Kee Ho Shin

Tero Viitanen

Maryam Saeedifard

Ronald G Harley
title: Improved Modulation Scheme for Loss Balancing of Three Level Active NPC Converters
venue: IEEE Transactions on Power Electronics
year: 2017

abstract: This paper describes the operation of modular multilevel converter, an emerging and highly attractive topology for medium and high voltage applications. A new pulsewidth modulation (PWM) scheme for an arbitrary number of voltage levels is introduced and evaluated. On the basis of this PWM scheme, the semiconductor losses are calculated, and the loss distribution is illustrated.
author_names: Steffen Rohner

Steffen Bernet

Marc Hiller

Rainer Sommer
title: Modulation, Losses, and Semiconductor Requirements of Modular Multilevel Converters
venue: IEEE Transactions on Industrial Electronics
year: 2010

abstract: The three level neutral point clamped voltage source converter (NPC VSC) is widely used in high power medium voltage (MV) applications. To overcome its major drawback the unequal loss distribution among the semiconductors the use of active NPC (ANPC) switches was previously proposed. In this paper, a simple feedforward loss control scheme for the ANPC converter is presented. The principle of operation of the ANPC VSC is experimentally verified for the first time. Electrical measurements on a low voltage test bench prove the proper function of the ANPC converter. Infrared junction temperature measurements confirm the improved loss distribution using the new loss control scheme. Finally, the authors demonstrate the superior performance of the loss controlled ANPC converter in various MV applications.
author_names: Thomas Bruckner

Steffen Bernet

Peter K Steimer
title: Feedforward Loss Control of Three Level Active NPC Converters
venue: IEEE Transactions on Industry Applications
year: 2007

abstract: Neutral point (NP) voltage drift is the main technical drawback of NP clamped (NPC) three level inverters. Traditional space vector pulsewidth modulation (SVPWM) is incapable of controlling the NP voltage for high modulation indexes and low power factors. Virtual SVPWM (VSVPWM) is capable of controlling the NP voltage under full modulation indexes and full power factors. However, this modulation strategy is more complex than SVPWM, increases the switching frequency, and deteriorates the output waveforms of the inverter. A novel PWM concept that includes NP voltage balancing conditions is proposed. Based on this concept, a hybrid modulation scheme that uses both SVPWM and VSVPWM is presented for complete control of the NP voltage in NPC three level inverters. The performance of this new modulation approach and its benefits over SVPWM and VSVPWM are verified by simulation and experiments.
author_names: Weidong Jiang

Shao-wu Du

Liu Chang

Yi Zhang

Qing Zhao
title: Hybrid PWM Strategy of SVPWM and VSVPWM for NPC Three Level Voltage Source Inverter
venue: IEEE Transactions on Power Electronics
year: 2010

abstract: The matrix converter is an array of controlled semiconductor switches that connects directly the three phase source to the three phase load. This converter has several attractive features that have been investigated in the last two decades. In the last few years, an increase in research work has been observed, bringing this topology closer to the industrial application. This paper presents the state of the art view in the development of this converter, starting with a brief historical review. An important part of the paper is dedicated to a discussion of the most important modulation and control strategies developed recently. Special attention is given to present modern methods developed to solve the commutation problem. Some new arrays of power bidirectional switches integrated in a single module are also presented. Finally, this paper includes some practical issues related to the practical application of this technology, like overvoltage protection, use of filters and ride through capability.
author_names: Patrick William Wheeler

Jose R Rodriguez

Jon C Clare

Lee Empringham

Alejandro Weinstein
title: Matrix converters: a technology review
venue: IEEE Trans. Ind. Electron.
year: 2002

abstract: This paper presents a neutral point voltage control strategy for the three level active neutral point clamped (ANPC) converter using selective harmonic elimination pulsewidth modulation (SHE PWM) The control strategy introduces a small change in the switching angles, which varies the duty cycle of the zero level switching state, controls the neutral point current and, therefore, the neutral point voltage. The decision to vary a given switching angle takes into account the polarity of the output currents and the voltage across the lower dc link capacitor. The effectiveness of the proposed strategy is verified through extensive simulation studies and experimentally validated using a low power laboratory prototype.
author_names: Sridhar R Pulikanti

Mohamed S A Dahidah

Vassilios G Agelidis
title: Voltage Balancing Control of Three Level Active NPC Converter Using SHE PWM
venue: IEEE Transactions on Power Delivery
year: 2011

abstract: The neutral point (NP) potential of the three level neutral point clamped converters is needed to maintain balancing. Zero sequence voltage is the only freedom degree when carrier based pulsewidth modulation is utilized. Appropriate zero sequence voltage should be identified to control the NP potential. The relationship between the neutral current and injected zero sequence voltage is studied comprehensively, and two balancing algorithms of NP potential, respectively adopting searching optimization and interpolation methods, are presented. The theoretical optimum zero sequence voltage for controlling NP potential can be obtained by the latter proposed algorithm. Simulation and experimental results are shown to verify the validity and practicability of the proposed algorithms.
author_names: Chenchen Wang

Yongdong Li
title: Analysis and Calculation of Zero Sequence Voltage Considering Neutral Point Potential Balancing in Three Level NPC Converters
venue: IEEE Transactions on Industrial Electronics
year: 2010

abstract: About the Authors. Preface. Acknowledgements. 1 Introduction. 1.1 Wind Power Development. 1.2 Photovoltaic Power Development. 1.3 The Grid Converter The Key Element in Grid Integration of WT and PV Systems. 2 Photovoltaic Inverter Structures. 2.1 Introduction. 2.2 Inverter Structures Derived from H Bridge Topology. 2.3 Inverter Structures Derived from NPC Topology. 2.4 Typical PV Inverter Structures. 2.5 Three Phase PV Inverters. 2.6 Control Structures. 2.7 Conclusions and Future Trends. 3 Grid Requirements for PV. 3.1 Introduction. 3.2 International Regulations. 3.3 Response to Abnormal Grid Conditions. 3.4 Power Quality. 3.5 Anti islanding Requirements. 3.6 Summary. 4 Grid Synchronization in Single Phase Power Converters. 4.1 Introduction. 4.2 Grid Synchronization Techniques for Single Phase Systems. 4.3 Phase Detection Based on In Quadrature Signals. 4.4 Some PLLs Based on In Quadrature Signal Generation. 4.5 Some PLLs Based on Adaptive Filtering. 4.6 The SOGI Frequency Locked Loop. 4.7 Summary. 5 Islanding Detection. 5.1 Introduction. 5.2 Nondetection Zone. 5.3 Overview of Islanding Detection Methods. 5.4 Passive Islanding Detection Methods. 5.5 Active Islanding Detection Methods. 5.6 Summary. 6 Grid Converter Structures forWind Turbine Systems. 6.1 Introduction. 6.2 WTS Power Configurations. 6.3 Grid Power Converter Topologies. 6.4 WTS Control. 6.5 Summary. 7 Grid Requirements for WT Systems. 7.1 Introduction. 7.2 Grid Code Evolution. 7.3 Frequency and Voltage Deviation under Normal Operation. 7.4 Active Power Control in Normal Operation. 7.5 Reactive Power Control in Normal Operation. 7.6 Behaviour under Grid Disturbances. 7.7 Discussion of Harmonization of Grid Codes. 7.8 Future Trends. 7.9 Summary. 8 Grid Synchronization in Three Phase Power Converters. 8.1 Introduction. 8.2 The Three Phase Voltage Vector under Grid Faults. 8.3 The Synchronous Reference Frame PLL under Unbalanced and Distorted Grid Conditions. 8.4 The Decoupled Double Synchronous Reference Frame PLL (DDSRF PLL) 8.5 The Double Second Order Generalized Integrator FLL (DSOGI FLL) 8.6 Summary. 9 Grid Converter Control for WTS. 9.1 Introduction. 9.2 Model of the Converter. 9.3 AC Voltage and DC Voltage Control. 9.4 Voltage Oriented Control and Direct Power Control. 9.5 Stand alone, Micro grid, Droop Control and Grid Supporting. 9.6 Summary. 10 Control of Grid Converters under Grid Faults. 10.1 Introduction. 10.2 Overview of Control Techniques for Grid Connected Converters under Unbalanced Grid Voltage Conditions. 10.3 Control Structures for Unbalanced Current Injection. 10.4 Power Control under Unbalanced Grid Conditions. 10.5 Flexible Power Control with Current Limitation. 10.6 Summary. 11 Grid Filter Design. 11.1 Introduction. 11.2 Filter Topologies. 11.3 Design Considerations. 11.4 Practical Examples of LCL Filters and Grid Interactions. 11.5 Resonance Problem and Damping Solutions. 11.6 Nonlinear Behaviour of the Filter. 11.7 Summary. 12 Grid Current Control. 12.1 Introduction. 12.2 Current Harmonic Requirements. 12.3 Linear Current Control with Separated Modulation. 12.4 Modulation Techniques. 12.5 Operating Limits of the Current Controlled Converter. 12.6 Practical Example. 12.7 Summary. Appendix A Space Vector Transformations of Three Phase Systems. A.1 Introduction. A.2 Symmetrical Components in the Frequency Domain. A.3 Symmetrical Components in the Time Domain. A.4 Components 0 on the Stationary Reference Frame. A.5 Components dq0 on the Synchronous Reference Frame. Appendix B Instantaneous Power Theories. B.1 Introduction. B.2 Origin of Power Definitions at the Time Domain for Single Phase Systems. B.3 Origin of Active Currents in Multiphase Systems. B.4 Instantaneous Calculation of Power Currents in Multiphase Systems. B.5 The p q Theory. B.6 Generalization of the p q Theory to Arbitrary Multiphase Systems. B.7 The Modified p q Theory. B.8 Generalized Instantaneous Reactive Power Theory for Three Phase Power Systems. B.9 Summary. Appendix C Resonant Controller. C.1 Introduction. C.2 Internal Model Principle. C.3 Equivalence of the PI Controller in the dq Frame and the P+Resonant Controller in the Frame. Index.
author_names: Remus Teodorescu

Marco Liserre

Pedro Rodriguez
title: Grid Converters for Photovoltaic and Wind Power Systems
year: 2011

abstract: This paper presents transformerless multilevel power converters as an application for high power and/or high voltage electric motor drives. Multilevel converters: (1) can generate near sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference or common mode voltage; and (3) are suitable for large voltampere rated motor drives and high voltages. The cascade inverter is a natural fit for large automotive all electric drives because it uses several levels of DC voltage sources, which would be available from batteries or fuel cells. The back to back diode clamped converter is ideal where a source of AC voltage is available, such as in a hybrid electric vehicle. Simulation and experimental results show the superiority of these two converters over two level pulsewidth modulation based drives.
author_names: Leon M Tolbert

Fang Zheng Peng

Thomas G Habetler
title: Multilevel converters for large electric drives
year: 1999