Virtual-Space-Vector PWM for a Three-Level Neutral-Point-Clamped Inverter With Unbalanced DC-Links

In this paper, the properties and operation of the virtual-space-vector pulse-width modulation (PWM) for a three-level neutral-point-clamped inverter with unbalanced dc-links are studied. By quantitatively analyzing the characteristics of the revised space-vector diagram (SVD) with unbalanced dc-links, the defined virtual SVD (VSVD) for the unbalanced case is theoretically proven identical to the VSVD of the conventional virtual-space-vector PWM (VSVPWM) strategy with balanced dc-links. The well-developed and fast-processing methods to calculate the durations of the nearest three virtual vectors for the conventional VSVPWM can be directly utilized. In addition, a control strategy to realize the asymmetric control of the dc-link voltages with VSVPWM is also studied, and this method can adjust the unbalancing degree with a high accuracy for any modulation indexes and load power factors. Simulated and experimental results are given to validate the effectiveness.

[1]  Hirofumi Akagi,et al.  A New Neutral-Point-Clamped PWM Inverter , 1981, IEEE Transactions on Industry Applications.

[2]  C. Won,et al.  A Method to Compensate the Distorted Space Vectors in the Unbalanced Neutral Point Voltage of 3-level NPC PWM Inverters , 2016 .

[3]  Seung-Ki Sul,et al.  Asymmetric Control of DC-Link Voltages for Separate MPPTs in Three-Level Inverters , 2013, IEEE Transactions on Power Electronics.

[4]  Pragasen Pillay,et al.  A Hybrid PWM-Based DC-Link Voltage Balancing Algorithm for a Three-Level NPC DC/AC Traction Inverter Drive , 2015, IEEE Journal of Emerging and Selected Topics in Power Electronics.

[5]  Kai Yao,et al.  Three-level saddle space vector pulse width modulation strategy based on two-level space vector pulse width modulation for neutral-point-clamped three-level inverters , 2016 .

[6]  June-Seok Lee,et al.  Novel Discontinuous PWM Method of a Three-Level Inverter for Neutral-Point Voltage Ripple Reduction , 2016, IEEE Transactions on Industrial Electronics.

[7]  Hu Wenbin,et al.  A New DPWM Method to Suppress the Low Frequency Oscillation of the Neutral-Point Voltage for NPC Three-Level Inverters , 2015 .

[8]  Joan Rocabert,et al.  Closed-Loop Control of a Three-Phase Neutral-Point-Clamped Inverter Using an Optimized Virtual-Vector-Based Pulsewidth Modulation , 2008, IEEE Transactions on Industrial Electronics.

[9]  June-Seok Lee,et al.  Time-Offset Injection Method for Neutral-Point AC Ripple Voltage Reduction in a Three-Level Inverter , 2016, IEEE Transactions on Power Electronics.

[10]  Dushan Boroyevich,et al.  A comprehensive study of neutral-point voltage balancing problem in three-level neutral-point-clamped voltage source PWM inverters , 2000 .

[11]  Xing Zhang,et al.  Carrier-based generalised discontinuous pulse-width modulation strategy with flexible neutral-point voltage control and optimal losses for a three-level converter , 2016 .

[12]  C. Xia,et al.  Synchronized Space-Vector PWM for Three-Level VSI With Lower Harmonic Distortion and Switching Frequency , 2016, IEEE Transactions on Power Electronics.

[13]  Fred C. Lee,et al.  Switching Performance Optimization of a High Power High Frequency Three-Level Active Neutral Point Clamped Phase Leg , 2014, IEEE Transactions on Power Electronics.

[14]  Changliang Xia,et al.  Discontinuous Space Vector PWM Strategy of Neutral-Point-Clamped Three-Level Inverters for Output Current Ripple Reduction , 2017, IEEE Transactions on Power Electronics.

[15]  D. Boroyevich,et al.  The nearest three virtual space vector PWM - a modulation for the comprehensive neutral-point balancing in the three-level NPC inverter , 2004, IEEE Power Electronics Letters.

[16]  D. Boroyevich,et al.  A Carrier-Based PWM Strategy With Zero-Sequence Voltage Injection for a Three-Level Neutral-Point-Clamped Converter , 2012, IEEE Transactions on Power Electronics.

[17]  Kashem M. Muttaqi,et al.  Solar PV and Battery Storage Integration using a New Configuration of a Three-Level NPC Inverter With Advanced Control Strategy , 2014, IEEE Transactions on Energy Conversion.

[18]  Xinghuo Yu,et al.  An Improved Virtual Space Vector Modulation Scheme for Three-Level Active Neutral-Point-Clamped Inverter , 2017, IEEE Transactions on Power Electronics.

[19]  D. Boroyevich,et al.  Capacitor Voltage Balance for the Neutral-Point- Clamped Converter using the Virtual Space Vector Concept With Optimized Spectral Performance , 2007, IEEE Transactions on Power Electronics.

[20]  S. S. Jayasinghe,et al.  Diode-Clamped Three-Level Inverter-Based Battery/Supercapacitor Direct Integration Scheme for Renewable Energy Systems , 2011, IEEE Transactions on Power Electronics.

[21]  C. Xia,et al.  A Method for the Suppression of Fluctuations in the Neutral-Point Potential of a Three-Level NPC Inverter With a Capacitor-Voltage Loop , 2017, IEEE Transactions on Power Electronics.

[22]  S. Busquets-Monge,et al.  Pulsewidth Modulations for the Comprehensive Capacitor Voltage Balance of $n$-Level Three-Leg Diode-Clamped Converters , 2009, IEEE Transactions on Power Electronics.

[23]  Dushan Boroyevich,et al.  Fast-Processing Modulation Strategy for the Neutral-Point-Clamped Converter With Total Elimination of Low-Frequency Voltage Oscillations in the Neutral Point , 2007, IEEE Transactions on Industrial Electronics.

[24]  U. Choi,et al.  Simple Neutral-Point Voltage Control for Three-Level Inverters Using a Discontinuous Pulse Width Modulation , 2013, IEEE Transactions on Energy Conversion.

[25]  Joan Rocabert,et al.  Multilevel Diode-Clamped Converter for Photovoltaic Generators With Independent Voltage Control of Each Solar Array , 2008, IEEE Transactions on Industrial Electronics.

[26]  Kaushik Rajashekara,et al.  A New SVPWM for the Phase Current Reconstruction of Three-Phase Three-level T-type Converters , 2016, IEEE Transactions on Power Electronics.

[27]  S. Bernet,et al.  A comparison of three-level converters versus two-level converters for low-voltage drives, traction, and utility applications , 2005, IEEE Transactions on Industry Applications.

[28]  Zongbin Ye,et al.  Simplified PWM Strategy for Neutral-Point-Clamped (NPC) Three-Level Converter , 2014 .

[29]  Khalifa Al-Hosani,et al.  Space-Vector-Based Synchronized Three-Level Discontinuous PWM for Medium-Voltage High-Power VSI , 2014, IEEE Transactions on Industrial Electronics.

[30]  F. Lee,et al.  Space Vector Modulation for Three-Level NPC Converter With Neutral Point Voltage Balance and Switching Loss Reduction , 2014, IEEE Transactions on Power Electronics.

[31]  Pragasen Pillay,et al.  Modified DC-Bus Voltage-Balancing Algorithm Based Three-Level Neutral-Point-Clamped IPMSM Drive for Electric Vehicle Applications , 2016, IEEE Transactions on Industrial Electronics.

[32]  Changliang Xia,et al.  Adjustable Proportional Hybrid SVPWM Strategy for Neutral-Point-Clamped Three-Level Inverters , 2013, IEEE Transactions on Industrial Electronics.

[33]  Pragasen Pillay,et al.  Modified DC-bus voltage balancing algorithm based three-level neutral point clamped (NPC) IPMSM drive for electric vehicle application , 2014, IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society.

[34]  Shi Weng Gui,et al.  A Varied VSVM Strategy for Balancing the Neutral-Point Voltage of DC-Link Capacitors in Three-Level NPC Converters , 2015 .

[35]  Yiming Xu,et al.  A Simplified PWM Strategy for a Neutral-Point-Clamped (NPC) Three-Level Converter With Unbalanced DC Links , 2016, IEEE Transactions on Power Electronics.

[36]  Dushan Boroyevich,et al.  New feedforward space-vector PWM method to obtain balanced AC output voltages in a three-level neutral-point-clamped converter , 2002, IEEE Trans. Ind. Electron..